A STRUCTURAL AND MGRP'HQGENSTIC ENVESTiGATEQN OF THE VAQGHAN LEWES GLACiER ARE} MjAQEHT SKTGRS OF THE jUNEAU ECEFEELD, ALASKA; 1961 - W64 “vests §or H19 Degree of M. S. MIEEEEGAN STATE UNEVERSETY Theodore F‘ Freers 196-6 u WWn L ’ 3 University ABSTRACT A STRUCTURAL AND MORPHOGENETIC INVESTIGATION OF THE VAUGHAN LEWIS GLACIER AND ADJACENT SECTORS OF THE JUNEAU ICEFIELD, ALASKA, 1961-1964 by Theodore F. Freers This three—year study of the Vaughan Lewis Glacier in the Boundary Range north of Juneau, Alaska, involved investi— gations of the structure and deformation of a series of unique strain features, including surface wave—bands and associated two—dimensional ogives or arch bands (Forbes' bands). Three morphologic units in the glacier are described: (1) an accumulation névé zone at 5400 to 6000 feet, with an area of Siisquare miles; (2) an icefall zone, a mile long with a descent of 1600 feet; and (3) a negative wastage zone extending from the mean névé—line (4200 feet) a distance of 6 miles to the terminus. Wave—ogives are first exposed on the icefall's apron and are increasingly revealed down— glacier as successive hyperbolic ogive arcs, with crests up to 800 feet apart. In plan, they are convex downglacier. In cross—section, the waves have a maximum apparent amplitude of 80 feet. Measurements have been made on an array of move- ment stakes placed in the accumulation and ablation zones. Comparative firn structure studies and surface movement records have also been obtained on both the Vaughan Lewis and adjoining Taku Glacier. A regime comparison is also Theodore F. Freers developed by area—elevation analyses, showing the Taku with a 6 to 1 ratio of névé to wastage area, opposed to a 2 to 1 ratio on the Vaughan Lewis Glacier. With respect to the Vaughan Lewis bands, alternating zones of clean and debris-entrained ice accentuate the pattern although, in fact, the bands consist of myriads of tectonic folia, apparently slice or flow-crystallization structures. White-ice layers or aerated "veins" occur as inlays in the folia. They appear on the surface as fine—grained, non- foliated stripes of white—ice, l to 2 feet wide and several hundred feet long. They are intermittent and usually dip steeply upglacier, or inward towards the center from the sides. In the icefall zone, folds of ice are found separated in places by white-ice layers similar to, but wider than, those of the wave—bands. Planimetric and ice-core studies, as well as cross-sectional plotting of these structures, provide clues to the genesis of the wave—bands and ogives. The white-ice layers between folds in the icefall, and the white-ice layers within the wave-bands, are indicated to have originated as winter snow compressed between the folds. At the base of the icefall, where the surface gradient falls off sharply, the complex of folds is raised above the glacier surface by increased compression. The structures are seemingly abetted by summer ablation on the downglacier side, thus furthering the wave appearance. As the deformed ice moves downvalley, differential ablation at the surface continues to reveal the white-ice structures as embossed features Theodore F. Freers extending across—glacier in the remarkable arcuate patterns described. The combined character of the waves and ogives, which in this study specifically defines the wave-ogive, is considered to be the result of rhythmic discontinuous englacial movements and stresses, probably reflecting annual climatic perturbations in the névé zone. On this basis the total of 73 wave-bands and ogives measured in the negative wastage zone suggests that ice presently exposed at the terminus is less than a century old. The empirical and structural observations and streaming flow profiles described corroborate that the lower glacier area is in a state of down-wastage and slow regression in spite of the vigorous regime of the upland néve and the dynamic stresses revealed by wave—band development below the icefall. The explanation reverts to the area-elevation statistics, which illustrate the proportionately small nourishment zone involved. .A STRUCTURAL AND MORPHOGENETIC INVESTIGATION OF THE VAUGHAN LEWIS GLACIER AND ADJACENT SECTORS OF THE JUNEAU ICEFIELD,.ALASKA, l961-l96h By Theodore F. Freers A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Geology 1966 ACKNOWLEDGMENTS This study was supported primarily by the Glaciological Institute of the Department of Geology at Michigan State University in cooperation with the Juneau Icefield Research Program (JIRP) of the Foundation for Glacier Research, Seattle, Washington. .Additional support was also rendered by funds from the Alaska Glacier Commemorative Project of the National Geographic Society, washington, D. c. During the later phases of this research the writer also gained the advantage of being a participant in the MSU Summer Institute of Glaciological Sciences; aided by the National Science Foundation. Sincere appreciation is extended to Professor Maynard M. Miller for suggesting the ihesis tOpic, for making many use- ful suggestions in the fietd and in the office, for helping to integrate this study wifh related investigations in.Alaska, and also for his never-endirg enthusiasm and encouragement. Specific thanks is given to all of the 1961 JIRP participants, eSpecially to Edward C. And'ess, for information obtained during our joint firn stratf raphy studies and to Douglas K. Bingham for his calculatiins of the movement data. The writer also eSpecially appreéiates the help given him by the 1 staff and research associate: of the i963 JIRP eXpedition and I participants in the allied Giaciologicai Institute of that year. ii To other investigators in other years of the Juneau Icefield program, from whose reports I have drawn useful information, I am likewise indebted. Thanks is also extended to Dr. Hugh Bennett, Dr. Chilton Prouty, and Dr. James H. Trow for serving with Dr. Miller on the writer's thesis committee and for critically reviewing the manuscript and making helpful suggestions. .And last but not least, the writer greatly appreciates the many hours Spent by his wife, Petra, in editorial help and in typing the manuscript. iii CONTENTS Page ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . ii LIST OF FIGURES . . . . . . . . . . . . . . . . . . . vi LIST OF APPENDED DATA . . . . . . . . . . . . . . . . ix PREVIEW OF THE RESEARCH PLAN. . . . . . . . . . . . . 1 I. INVESTIGATIONS ON THE VAUGHAN LEWIS GLACIER . . . 6 PHYSICAL SETTING .~. . . . . . . . . . . . . . 6 THE 1961—6h INVESTIGATIONS OF THE VAUGHAN LEWIS GIACIER o o o o o o o o o o o o o o o o 7 1. Area and Hypsometric Relationships . . . . 2. Glaciomorphic Sectors. . . . . . . . . . . 8 a. The Crestal Néyé or Prime Accumulation zone. 0 O O O O O O O O O O O O O O O O 9 (l) Firn Stratigraphy . . . . . . . . . 10 (2) Glaciothermal Measurements. . . . 15 (3) Interpretation of Stratigraphy and DenSity o o o o o o o o o o o o o 17 (4) Interpretation of Electrothermal Bore-Rates and Englacial Tempera- tures . . . . . . . . . . . . . . . 18 b. The Icefall Zone. . . . . . . . . . . . 21 c. The Wave-Band Zone. . . . . . . . . . . 26 d. The Ogive Zone. . . . . . . . . . . . . 30 e. Terminal Sector . . . . . . . . . . . . 32 3. Névé-Line Characteristics and Positions. . 33 u. Surface Movement Records . . . . . . . . . 37 a.Surveyed Observations . . . . . . . . . 37 b. Strain-Rate Analysis. . . . . . . . . . hi iv Page C. Structural Analysis . . . . . . . . . . LIZ II. COMPARISONS WITH OBSERVATIONS ON THE TAKU AND OTHER JUNEAU ICEFIELD'GLACIERS. . . . . . . . . ES HIGHER TAKU NEVE. . . . . . . . . . . . . . . us INTERMEDIATE TAKU NEVE. . . . . . . . . . . . Lib VLOHERTAKUNEVE’...............11,6 OTHER BANDED GLACIERS ON THE JUNEAU ICEFIELD. us III. WORKING HYPOTHESIS ON WAVE-BANDS OF THE VAUGHAN LEWIS GLACIER O O O C O O O O O O O O O 0 O O 0 ’49 OTHER THEORIES. . . . . . . . . . . . . . . . R9 DISCUSSION WITH RESPECT TO THE VAUGHAN LEWIS PROBLEM O O C O O O O O O O O O O O O i. O O O 53 SUMMARY or RESULTS AND CONCLUSIONS. . . . . . 55 Iv. SUGGESTED.ADDITIONAL INVESTIGATIONS . . . . . . 62 SELECTED REFERENCES . . . . . . . . . . . . . . . . . 6h ILLUSTRATIONS . . . . . . . . . . . . . . . . . . . . 68 APPENDED DATA . . . . .,. . . . . . . . . . . . . . . 106 G LOSSARY o o o o o o o o o o o o o o o o o o o o o o 13 1 Figure 1. 2. 10. II. 12. LIST OF FIGURES Juneau Icefield, Alaska, with index map. . . . Oblique aerial photo of the Vaughan Lewis Glacier icefall and wave-bands (Photo by C. P. Egan, 27 September 1963) . . . . . . . . Vertical aerial photo of lower Vaughan Lewis Glacier showing ogives in Sector D and the terminal area Sector E. Note ice-dammed lake at each of termini. (U. S. Navy Photograph, 11 July 19h8). . . . . . . . . . . . . . . . . Vaughan Lewis-Gilkey Glacier Complex . . . . . Cumulative area curves of the Vaughan Lewis and Taku Glaciers representing total areas below successive ZOO-foot (60 m) contours. . . Vaughan Lewis Glacier area-elevation histo- grams showing area between successive 200- foot (60 m) contours . . . . . . . . . . . . . Glaciomorphic sectors or regime zones of the Vaughan Lewis Glacier. . . . . . . . . . . . . Schematic map of zone.AnA' Taku-Vaughan Lewis Glaciers, showing neve limits and location of main research sites. .. . . . . . . . . . . Stratigraphy of main test pit at Camp BB in late August, 1961. (In cooperation with “dress, 1962) O O C . O O O O O O O O O O O O O 1961 density profiles of upper firn in Vaughan Lewis-Taku glaciomorphic Sector A} (Camp BB) . Density profile in 1963 firn, Site BB (Taku Glacier) and rammesonde profile, Sector A (vaughan Lewis Glacier). . . . . . . . . . . . Stratigraphy of crevasse wall, upper Taku Glacier, Site 8D, elev. 5700 feet (1750 m), September, 1961. (After.Andress, 1962). . . . vi Page 68 7O 72 73 7‘4- 75 76 77 78 79 80 81 Figure 13. 1h. 15. 16. 17. 18. 19. 20. 21. 22. 23. 2h. Stratigraphy at Site 8A and firn thickness at Site 108 measured from hand auger cores (Adler Andress, 1962). . . . . . . . . . . . . Density profile, Sector A}, Sites 8A and 83, upper Taku GlaCier (Dave. 0 o o o o o o o o o o Electrothermal glacier drill, 2000-watt element; 120-volt wiring detail as used at Site 8A, Upper Taku Glacier, elev. 5900 feet (1800 m), August-September, 1961. (After .Andress, 1962) . . . . . . . . . . . . . . . . Electrothermal borer bore rate and depth of enetration time at Site 8A, 29 August to E September 1961 o o o o o o o o o o o o o o o Englacial temperature profile in electrothermal bore hole at Site 8A, Sector.A', as of h Sep- tember 1961. O O 0 O O O O O O O O O O O O O O Recumbent isoclinal fold in bubbly glacier ice, north side of glacier, near base of Vaughan Lewis icefall (Photo by T. F. Freers, 9 Sep- temer 1961) O O 0 0 O O O O O O O O O 0 O O 0 Surface expression of white-ice layers on crest of_wave-band in Sector C. View looking across glacier toward south. (Photo by T. F. Freers, 10 September 1961). . . . . . Schematic representation of the Vaughan Lewis icefall, Sector B, showing relationship of main structural features between #000 and 5000 feet (1225 and 1675 m) elevation. . . . . Ages of wave-bands, Sector C, on the Vaughan Lewis Glacier. . . . . . . . . . . . . . . . . Cross-sectional surface profile of Wave-Bands 1 to 5 along the centerline of the Vaughan Lewis Glacier (September, 1963). . . a . . . . Wave-Band 2 showing foliation and non-foliated white-ice along a crevasse wall (September, 19 3). O O O O O O O O O O O O O O O O O O O O Wave-Band u showing foliation and non-foliated white-ice along a crevasse wall (September, 1963). O O O O O O O O O O O O O O O O O O O 0 vii Page ‘82 83 8h 85 86 88 90 91 92 93 9h 95 Figure 25. 26. '27. 28. 29. 3o. 31. 32. 33. Page Photo of smooth relatively unbroken white- ice cores and rough broken bubbly glacier ice cores. Cores taken within a yard (meter) of each other in Sector C. (Photo by T. F. Freers, 10 September 1961). . . . . . 97 1961 surface velocities and movement in the icefall and wave-band zones of the Vaughan Lewis Glacier. . . . . . . . . . . . . . . . . 98 Two-year, 1961 to 1963, velocities and movements in the wave-band zone of the Vaughan Lewis Glacier. . . . . . . . . . . . . 99 196E velocities, movements and stress tensor in the wave-band zone of the Vaughan Lewis Glacier. . . . . . . . . . . . . . . . . . . . 100 1960 and 1961 surface movement along Profile V111 on the North Branch, Taku Glacier in the Camp 8 Sector. . . . . . . . . . . . . . . 101 1961 surface movement along Profile VII on the North Branch, Taku Glacier in the Camp 9 SeCtor O O O O O O O O O O O O O O O 0 O O O O 102 1960 and 1961 surface movement along Profile IV on the Main Branch, Taku Glacier in the Camp 10 Sector . . . . . . . . . . . . . . . . 103 Hypothetical sequence of events in the development of a white-ice layer in the Vaughan Lewis Glacier (cross-sectional views). 10h Hypothetical sequence of events in the development of a white-ice anticline in the Vaughan Lewis Glacier (plan views) . . . . . . 105 viii Appendix A. LIST OF APPENDED DATA Page Area Between Successive ZOO-foot (60 m) Contourg From the Terminus to the Upper Neve Zone on the Vaughan Lewis Glacier. . . . . . . . . . . . . . . . . 106 Firn Density Measurements and Upper Firn Stratigraphy of the Vaughan Lewis- Taku Névé, 6000 Feet (1825 m), September, 1961. . . . . . . . . . . . . 107 Part 1 - Site 88 (Hand Auger Cores). 107 Part 2 - Site 83 (Test Pit, 250- 500 CC Hand Corer). . . . . 108 Firn Density Measurements and Upper Firn Strati raphy of the Van han Lewis- Taku Névé, 000 Feet (1825 m , August, 1963 O O O O O O O O O O O O - O O O O O O 109 Part 1 - Siteg8B Firn Stratigraphy (Hand,Auger Cores). . . . . 109 Part 2 - Site 88 (Test Pit, 250- 500 cc Hand Corer). . . . . 110 Firn Density Measurements and Upper Firn Strgti raphy of the Vaughan Lewis- Taku Néve, 000 Feet (1825 m), July, 1962 O O O O 0 O O O O O O O O O O O O O 111 Part 1 - Site 8A 0 o o o o o o o o o 111 Part 2 "‘ Site BB 0 o o o o o o o o o 111 Camp 8A - Thermal Bore Drilling Rate Readings, 1961 C O O O C O O C O O C O O 112 Camp 83 - Thermistor Measurements - 151-foot (E6 m) que Hole. . . . . . . . 118 Camp 8B - Thermistor Measurements - 60-foot (20 m) Bore Hole . . . . . . . . 121 ix .Appendix H Page Surface Movement in the Icefall and Wave-Band Sectors of the Vaughan Lewis Glacier, 1961 and 1961 to 1963. . . 123 Part 1 - wave-Band Zone . . . . . . . 123 Part 2 - Icefall Zone . . . . . . . . 12h Surface Movement and Stress Tensor in the Have-Band Zone of the Vaughan Lewis GlaCIQI', 1961-L O O O O 0 O O O O O O O O O 125 Surface Movement Measurements Along Profile VIII, North Branch Taku Glacier in the Camp 8 Sector. . . . . . . . . . . 126 Part 1 - 1960 Measurements. . . . . . 126 Part 2 - 1961 Measurements. . . . . . 127 Surface Movement Measurements Along Profile V11, North Branch Taku Glacier in the Camp 9 Sector, 1961. . . . . . . . 128 Surface Movement Measurements.Along Profile IV, Main Branch Taku Glacier in the Camp 10 Sector. . . . . . . . . . . . 129 Part 1 - 1960 Measurements. . . . . . 129 Part 2 - 1961 Measurements. . . . . . 130 PREVIEW OF THE RESEARCH PLAN The Vaughan Lewis Glacier1 is nourished by the crestal névé of the Juneau Icefield in the.Alaska-Canada Boundary Range (Fig. 1). This glacier displays one of the most striking series of ogives or Forbes' bands of any glacier in the world. The spectacular nature of these bands (Figs. 2 and 3) has invited the attention of early researchers on the Juneau Icefield both on the ground and during many aerial reconnaissance and survey flights over the region (Miller, 1952a). Such has also stimulated the present Investigation carried out intermittently between 1961 and 196h (Freers, 1965a)- The Vaughan Lewis Giacier with its pronounced pattern of crevasses, surface undulation, and internal structures presents an array of complex problems in structural glaciology and glacier mechanics. From the accumulation zone to the terminus, this glacier involves many areas of stress--the most prominent of which is the icefall. Among other unusual characteristics is the termination of a large part of the glacier in interior drainage basins (ice-dammed lakes) while the rest flows on toward Berners Bay and the ocean (Fig. 3). + 1Named for William.Vaughan Lewis (1907-1961) eminent British glaciologist from Cambridge University, who was tragically killed in an automobile accident while enroute to Alaska as one of the first visiting professors of the Glaciological Institute and the Juneau Icefield Research Program during the summer of 1961 (Journal of Glaciology, 1963). I 2 The unique glaciological problems on this glacier are too complex to be resolved by the reconnaissance-type investi- gation herein involved, but it is hOped that this investi- gation will at least provide some fundamental information essential to future glaciological studies of the Vaughan Lewis Glacier or any other glacier having similar structural characteristics. The Vaughan Lewis Glacier problems were brought to the author’s attention in 1961 by Dr. Maynard M. Miller, Director of the Juneau Icefield Research Program (JIRP) and also of the Glaciological Institute at Michigan State University. He suggested that a brief survey of the glaciomorphology, structure, and surface movement be made during the 1961 field season with additional data gathered during a subsequent summer season. .A number of descriptive notes were made on this glacier's characteristics in.August and September 1961 in addition to initiating a program of surface movement records. In 1963, the glacier was again studied with the emphasis on obtaining more quantitative data. ‘With the help of other participants in the Juneau Icefield Research Program in 196R, further information has becOme available for incorpo- ration in this study (Havas, 1965; Kittredge, 1965). The surface movement measurements have yielded data that can be compared with other wave-band glaciers elsewhere in the world and which, when fully analyzed, will reveal the nature of stresses present at the surface of such glaciers. 3 .A significant factor in the study is the wealth of glaciological data gathered for the past 20 years on the upper Taku Glacier, the north branch of which adjoins the Vaughan Lewis névé (Fig. h). These data should eventually be invaluable as control for comparative analysis of the mass transfer of the Vaughan Lewis and Taku Glaciers. Also invaluable are the JIRP field station meteorological records from Camps 8 and 10, which are representative of the high and low névé zones of the Juneau Icefield. Previous morphological investigations of glaciers on the Juneau Icefield and elsewhere in the Boundary Range provide further information which can be closely allied to the Vaughan Lewis Glacier study. In addition glaciological studies in other cordilleran regions of the world provide a basis for some comparison outside of the Alaskan region (e.g., Vareschi, 19h2; King and Lewis, 1961; and Miller and Prather, 1965). Studies of the Vaughan Lewis and Taku Glaciers centered around two main camps on the Juneau Icefield. One of these was Camp 10 (Fig. 1), a permanent reSearch station comprising a half-dozen aluminum covered buildings situated on a granitic nunatak about hOO feet (120 m) above the 3500-foot (1075 m) névé of the Taku Glacier. This was the main base of Operations,. particularly for the lower névé studies. The upper névé head- quarters was Camp 8, lying three miles (5 km) from the eastern edge of the Vaughan Lewis névé (Figs. 1 and E). Camp 8 has several large permanent buildings and served as the main base of operations for the upper névé studies of the Taku and h Vaughan Lewis Glaciers. Temporary field camps were also occupied on the upper Taku névé, 6000 feet (1825 m) for Camps 8A.and 8B, and at the tOp of the Vaughan Lewis icefall, 5600 feet (1700 m) for Camp 18. During fair weather personnel worked from these various field camps making glaciological, geological, botanical and meteorological observations and measurements. Even summer storms are not uncommon in the high Boundary Range, so fortunately during the more severe storms with winds up to 100 miles (160 km) per hour, the field parties were able to take refuge in the permanent station facilities. In the course of these studies, travel on the glacier was done on skis and by oversnow vehicles. Of course, in areas below the névé-line, all travel was on foot with mountaineering safety precautions constantly invoked. The combination of oversnow vehicles, permanent campsites, and long summer daylight often permitted up to 12 full hours of field work each day. Initially the investigation plan regarding the vaughan .Lewis Glacier involved surface movement measurements by theodolite in and below the icefall, and the obtaining of structural orientation data on in-ice structures of the apron of the icefall with Special attention to the wave-bands and ogives. The essential reconnaissance observations and measurements were accomplished in 1961. During the subsequent field seasons additional data were gathered on the stratigraphy of the upper vaughan Lewis firn-pack and adjoining upper Taku S névé, as well as on the inlaid structures of the lower part of the glacier and in its terminal zones. Some of these data are incorporated as a matter of record as well as for purposes of this present study. The raw data and notes have now been analyzed and a literature survey completed. These analyses comprise the main element of this presentation. The hOpe is reiterated that the conclusions drawn from the analyses may be of value in the continuing phases of these icefield investigations. I. INVESTIGATIONS ON THE VAUGHAN LEWIS GLACIER Physical Setting The Vaughan Lewis Glacier as part of the Juneau Icefield is located in the Northern Boundary Range of the Alaska-Canada Coast Mountains. Its Latitude is about 58°h8' N., Longitude 13h°12'W (Fig. 1). Its drainage is westward from the summit névé of this icefield, and its nourishment as well as wastage areas lie entirely in southeastern.Alaska. The glacier's cirque névé is on the south flank of Mt. Ogilvie, 7780 feet (2375 m), a boundary peak on the British ColumbiaeAlaska border (Fig. u).1 Regionally the Coast Mountains, in this sector referred to as the Boundary Range (Bostock, 19h8), comprise a northwest-trending cordillera with a central core of a granitic lntrusive--the Coast Range Batholith. On both flanks of the Boundary Range, the surface geology grades outward from this crystalline core into metamorphic and then sedimentary rocks (Buddington and Chapin, 1929). The Juneau Icefield is a large area of coalesced valley and mOuntain glaCiers embracing upwards of 1200 square miles (3000 sq km). Two main glacial trunks flow from the crestal ’ 1Note recently published U. S. Geological Survey Juneau (D-l) Quadrangle 1960 showing this glacier also bounded on the north by the Storm Peaks (Gale, Typhoon, and Blizzard) and on the east by the Matthes Glacier (equivalent to what has been referred to by JIRP for many years as the North Branch, Taku Glacier); In.this study, for consistency with other published reports, the older terminology is applied. 6 7 névé at 6200-6500 feet (1900—1975 m); these are the Taku Glacier, draining south to Taku Fiord in Alaska, and the Llewelyn Glacier which drains northward to terminate at 2500 feet (750 m) near Lake Atlin in northern British Columbia (Fig. 1). On the Taku Glacier, studies have been conducted by the Juneau Icefield Research Program since 19h6 in three primary zones. .A lower hOOO-foot (1225 m) zone, a broad intermediate 5000-foot (1525 m) bench zone, and an upper 6000-foot (1825 m) crestal plateau. Part of this upper névé plateau nourishes the Vaughan Lewis Glacier, as noted in figure 1. The 1961-6h Investiggtions of the Vaughan Lewis Glacier 1. Area and Hypsometric Relationships The Vaughan Lewis Glacier (Fig. h) is an "alpine” glacier as defined by.Ah1mann(l9h8). Actually, the glacier's shape, when plotted on an area-elevation graph (Fig. 5), is that of a valley glacier of the alpine type. The combined surface ice and firn of the Vaughan Lewis Glacier cover an area of about 9 square miles (25 sq km)(Appendix A). The prime area of positive or net acCumulation above the 1961-65 mean seasonal névé-line at h200 feet (1275 m) has an area of approximately 6.10 square miles (15.20 Sq km) (Fig. 6). The prime ablation zone, from an altitude of h200 feet (1275 m) to the terminal area, covers an area of about 2.9M square miles (7.37 sq km). This zone is well illustrated in figure A. From the figure 6 plot it is also seen that by far the greatest 8 area, 5.65 square miles (1h.18 sq km), lies between the Shoo-foot (1650 m) and 6000-foot (1825 m) contours, with the least in the icefall sector or spillway zone where an area of less than 0.08 square miles (0.20 sq km) lies between 3800 feet (1150 m) and 5u00 feet (1650 m). Regime-wise this spillway may therefore be considered of negligible import. 2. Glaciomorphic Sectors The morphology of this glacier encompasses three major divisions: the high-level cirque basin, the intermediate level icefall section, and the main lower level valley glacier segment. The total, in fact, represents the Vaughan Lewis- Gilkey Glacier complex (see again Figs. 2 and 3). Detailed description of each of these general morphologic units is facilitated by further breakdown into six glaciomorphic and regime sectors as shown in figure 7. One of these, Sector.AqA', ‘is common to the Vaughan Lewis and the upper Taku Glaciers. The other four (B, C, D, and E) lie only on the Vaughan Lewis Glacier. Area A-A' is 'a 5800 to 6000-foot (1775-1825 :11) névé zone on the vaughan Lewis—Taku Glacier divide (see map in Fig. 7). In this zone the only pertinent research with respect to this present study involved measurements on firn stratigraphy, density, glaciothermal conditions, and ablation. Movement records were also obtained on an across-glacier transect bearing approximately due west from Camp 8, as discussed later. In figure 7, Sector.A represents the prime accumulation zone lying above the tap of the icefall; i.e., above 5500 9 feet (1675 m). In this zone the first indications of strain from tensile stresses in the icefall are seen as arcuate crevasses, exposed in some years at elevations down to about 5500 feet (1675 m). Sector B represents the highly crevassed and seracced and relatively narrow area of the icefall ranging from 5500 feet (1675 m) down to h000 feet (1225 m). Sector C is the apron-like zone of wave-bands extending fan-wise out from the foot of the icefall. This apron is longitudinally about 1.5 miles (2.5 km) in length lying between the elevations of #000 feet (1225 m) and 3600 feet (1100 m). Sector D is the narrow zone of ogives (Forbes' bands) which extends into the terminal sector of the glacier. .Arbitrarily this zone ends when the ice has become so ablated and cregassed that the bands are no longer recognizable; i.e., below an elevation of approximately 2100 feet (6&0 m). Sector E is defined as the area of the terminus lying between the elevations of 2100 - 1600 feet (6&0 - #90 m). a. The Crestal Neva or Prime.Accumulation Zone “While part of this sector (Fig. 8) actually lies between 5600 - 5900 feet (1700 - 1800 m) on the crestal have of the Taku Glacier, it may be assumed that the general climatic conditions are comparable to those affecting the vaughan Lewis névé at 5600 - 5900 feet (1700 - 180mm).l For the present study, investigations in this sector were made on 1Some evidence, however, has been reported, based on recent weather observations at Camps 18 and 8 that the upper Taku segment is in fact slightly more continental in geophysical character than the vaughan Lewis névé in that it is higher and somewhat farther inland. 10 the firn stratigraphy, on glaciothermal conditions in the uppermost firn-pack, and on ablation and accumulation. These observations are applicable to both of these adjoining glaciers. (l) Firn Stratigraphy Investigation of the firn stratigraphy was made using ‘various techniques to obtain stratigraphic profiles. The most accurate but laborious method is to dig a test pit into the firn, but it usually gives only limited results because of the great time and energy involved in reaching significant depths. Crevasse wall studies are the next most reliable method and one which permits depths of 60 to 100 feet (18 to 30 m) to be obtained. The 3-inch (7.6 cm) diameter hand core auger (old S.1.P.R.E. model), hereafter referred to as hand auger, is almost as reliable a method. This hand auger allows penetration of the firn to nearly as great depths, but again at a considerable expenditure of time and energy. In this study a depth of only 58 feet (17.6 m) was reached using this technique. The fourth method is the Rsnunsonde or sounding probe technique which allows firmness character— istics of the firn to be determined to shallow depths; the maximum.being about 15 feet (h.5 m). The fifth and last method is the use of an electrothermal borer. This is the least reliable, but permits information at the greatest depths. .As such, it can furnish supplemental information which in conjunction with that from the four other methods is valuable. If possible, a combination of all of these 11 methods is desirable in such glaciological interpretations. The main accomplishments of these measurements were determination of density profiles and the amount of retained net accumulation (Figs. 7-12). Test pitsi--During the 1961 field season a test pit (83, Fig. 8) was dug at Camp 8B to a depth of 20 feet (6 m). The 1960 ablation surface was found at a depth of 18.5 feet (5.6 m) (Fig. 9). .At the time of this measurement (9 September 1961) there was nearly two feet (0.6 m) of snowcover on the 1961 ablation surface. Thus the firn thickness representing net retained accumulation for the 1960-61 budget year was 17.5 feet (5.3 m). Density in this 17.5-foot (5.3 m) increment ranges from 0.52 to 0.59 giving a mean or bulk density of 0.55. Density determinations (Appendix B, Part 2) were made in the pit wall using a 250-500 cc hand corer (Fig. 10). Figure 9 represents the south and west walls of the test pit (88-61). It is noted that the date of this field sketch was 9 September 1961. This was a week past the end of the 1961 effective ablation season at this elevation. Many diagenetic structures are shown in the 1960-61 firn increment. Among these were ice strata, columns and lenses and other irregular glands of diagenetic ice (Miller, 19553). A,similar test pit (8B-63) was dug in 1963 at Camp BB.‘ Again, density determinations were obtained by using a 250- 500 cc hand corer in the pit walls. The density profile for this pit (Fig. 11) reflects a significant depth-hoar stratum at about in feet (u m) (see Appendix C, Part 2). 12 Crevasse walls.--In 1961 the stratigraphy of a crevasse located at Site 8D (Fig. 8) about one-half mile south of Site 8A.was measured as a check against the results obtained by the other methods. The results are compared in the measured stratigraphy for Sites 8D and 8A.in figures 12 and 13. This crevasse reached a maximum apparent depth of 95 feet (29 m). The 1960—61 net retained accumulation measured in this crevasse is approximately the same as that given in test pit BB, in spite of the fact the 80 site was at a 200- foot (60 m) lower elevation. The retained accumulation segments for earlier years were also measured in this and adjoining crevasses with the results extending the record back with confidence to 1951 (Fig. 12, Site 8D at 5700-foot [1750 m] elevation.) ' Hand auger.-2A hand auger was used within 25 feet (7.5 m) of the 1961 Camp BB test pit and also as close to the electro- thermal bore site.l Core samples were taken at selected intervals for density determination. Because of compressive and torsional stresses exerted on the core samples by drilling, the accuracy of the deep bore-hole densities is considered to be less than the smaller hand corer densities obtained in test pits. Density determinations in the test pit and upper crevasse wall segments were made from two or more samples at the same level. Each density determination (Appendix B, Part 1) was made from single core samples representing one foet (0.3 m) or less in vertical length. A5 these were obtained by vertical drilling instead of the 13 horizontal samples taken in the test pits and crevasse wall measurements, this accounts for some of the variation between the readings obtained by these different methods. The 1962 summer density measurements were made using the hand auger to obtain cores of firn to a depth of about 30 feet (9 m). The two bore-hole sites were again at 8A and 83 (Fig. 8). Figure 1h shows the density profiles at these two sites and reveals the close correlation possible on a flattish névé surface over a distance of as much as a mile (1.6 km). The 1961 ablation surface is interpreted on the basis of the reduced density (depth-hear effect) at about 17 feet (5 m) (Egan, 1965; also.Appendix D). Ranunsonde.--Rennnsonde penetrations were made in Sector A.in 1963. The ranunsonde is an instrument which. measures resistance of snow or firn to penetration when a known weight is drapped a known distance forcing the pene- trometer (ram) into the firn. The resulting data were plotted as a ram profile.for comparison with the previously noted density curve in figure 11. The rough correSpondence of these curves is considered corroborative. Electrothermal borer.--The electrothermal borer (Fig. 15) was used to penetrate to 151 feet (M6 m). This particular borer, a type not previously used on the Juneau Icefield, was modified from a pattern employed on the glaciers of Mt. Rainier (Miller, 1959). The drill unit was operated from a 2.5 XV, 120 volt, Onan generator. The drill was started in a 22—foot (6.7 m) 11+ hand auger hole. It was suspended by a 7/16 inch (1.1 cm) manila rape, marked at 5-foot (1.5 m) intervals. Electricity was conducted to the drill bit by General Electric insulated cord (NP-1300) of 0.58 inch (1.5 cm) 0. D., consisting of double copper leads, embedded in composition and sheathed with black rubber. Theeflectrical leads were connected to the drill through a watertight coupling. Low power (1.5 KW) used in the borer allowed slow penetration. This slow rate of penetration with readings taken every one-half hour allowed an interpretation of sub- surface ice structures and density differences. Thermal boring began at 1815 hours on 29 August 1961 and reached the total depth of 151 feet 2 inches (h6.2 m) on u September 1961. The elapsed time was 137 hours. .A total of 6 hours during this period the borer was shut down for maintenance and other reasons. The shut down times are recorded in.Appendix E. A.large knot in the suspension line 20 feet (6 m) above the borer at times would freeze to the drill-hole wall. The times of the knot freezing are indicated in figure 16 by the letters K. F. The freeze-ins occurred at depths of 29 feet (8.8 m), 131 feet (39.9 m) and 120 feet (36.6 m). Freeing of the frozen knot was accomplished at the 29-foot (8.8 m) depth by using short, quick jerks on the suSpension ropes.' This method did not work for the other deeper freeze- ins. To loosen these, anti-freeze was poured into the bore hole. The problem might have been prevented by tying a less 15 bulky knot; however, the freezing-in was turned to an advantage as it proved that subfreezing conditions existed in the firn-pack at these depths. These observations are substantiated in a later section when the actual measurement of englacial‘temperatures is discussed. Figure 16 is a graphical representation of the bore-rates at various depths. 'Also shown is a curve of total depth times total boring time. In other words curve A represents the bore-rates at Specific depths and indicates the variability of boring in the firn-pack as a result of density and temperature differences. Curve 3 represents the time it took to bore to any given depth. This latter curve also reveals the overall increase of the boring time with depth. Curve 3 is seen to approach an asymptote to the lower right corner of the graph. (2) Glaciothermal Measurements Data regarding the thermal characteristics in the upper 151 feet (h6 m) of firn on the 5950-foot (1825 m) neve (Sector A) were also gathered during the 1961 field season. This was done with the suSpicion that some knowledge of the englacial temperature characteristics of the crestal névé might prove to be germane to the long-term analysis of all factors possibly controlling mass transfer of ice through the Vaughan Lewis icefall. Because of logistical complications the data could be obtained, however, only on the adjoining Taku neve. Thermistor heat sensing devices were employed in the 151-foot (h6 m) electrothermal bore hole and the 60-foot 16 (18 m) auger hole, both at Camp 8A.(Fig. 8). The thermistor equipment was provided by the Foundation for Glacier Research. The GeOphysics Laboratory of the U. S. Geological Survey manufactured the equipment from Specifications established for the Juneau Icefield Research Program. The thermistors are ”small discs of sintered manganese and nickel oxide, 0.2 inches (0.5 cm) in diameter and 0.0a inches (0.1 cm) thick. .An axial copper lead, 0.02 inches (0.05 cm) in diameter, is secured to each with an intermediary spot of ceramic silver paste, all of which is enclosed in vulcanized cables. The resulting alloyed semi-conductor provides a h.h per cent negative change in electrical resistance per degree Centigrade in temperatures at room temperature and a 6 per cent change per degree Centigrade in the vicinity of -30°C. Western Electric Company manufactures this ther- mistor (Type 17A). Measurements can be made to an accuracy of 0.01°C by means of an appr0priate Wheatstone Bridge" (Miller, 1955b). ’ — Two thermistor cables (Nos. 332 and 333) were used at the site 8A. Each cable was identical, being 180 feet (53.9 m) with 18 thermistors placed at lO-foot (3 m) intervals. These cables were recalibrated in the spring of 1961 by the USGS Geophysics Laboratory and are believed accurate within the stated limits. Cable No. 332 was placed in the 60-foot, 3-inch (18.2 m) auger hole (Bore Hole No. 2, Fig. 8). Cable No. 333 was placed in the electrothermal bore hole (Bore Hole No. 1, Fig. 8). The bore holes were about no feet (12 m) apart 17 on an east-west line at Site 8A. .After the cables had been lowered into their respective holes, the tops of the bore holes were sealed to prevent significant air circulation. Readings were not made until the holes were thermally stabilized for periods from 2h to 72 hours. Readings were then made at all thermistor levels on a 6 to 2h hourly basis. All readings and times recorded are given in Appendices F and G, as previously listed by Andress (1962). For reasons made clear below, the interpretation of the above-noted glaciothermal records is given after discussion of the interpretation of the stratigraphic and density measurements. (2) Interpretation of Stratigraphy and Density Each of the techniques used to gather information on the Vaughan Lewis-Taku Glacier névé contributed to the overall knowledge of the net retained accumulation. Exami- nation of the data for each of the years (l96l-l96h) provides a basis of comparison in a later chapter, briefly considering aspects of mass transfer in the Vaughan Lewis and Taku Glaciers. As calculated from the area-elevation comparison in figure 5, over 60 per cent of the Vaughan Lewis Glacier accumulation zone lies at the same elevation as Site 83. Similarly, 30 per cent lies at the same elevation as the Site 8D crevasse south of 8A. This, added to their geographical proximitygmakes it reasonable to assume that the annual net retained accumulation on the névés of each of these glaciers is nearly the same. 18 in 1961 the net retained accumulation was 17.5 feet (5.3 m) of firn at the Camp 83 test pit, and 19.5 feet (5.9 m) of firn on a crevasse wall south of Camp 8A. Both of these accumulation increments had a bulk density of 0.56, or a water equivalent of 9.8 feet (2.98 m). .Although the 1962 measurements are not as complete, the densities determined from bore-hole cores taken at Sites 8A and 83 reveal a net retained accumulation of about 17 feet (5.2 m) of firn for the 1961-62 budget year. The 1963 test pit density profiles similarly reveal a total retained accumulation of 1h feet (h.3 m) of firn at Site 83 for the budget year 1962-63. The ram profile (Fig. 11) in Sector A also corroborates the stratigraphic similarity to the firn at Site 83. This additional evidence supports the conclusion of comparable net accumulation on the upper Taku néve and on the Vaughan Lewis néve. (h) Interpretation of Electrothermal Bore-Rates . andEngIacial Temperatures Data from the englacial temperature measurements reveal the presence of a retained 1960-61 winter's cold wave in Sector ArAf. The plotted depth profile of these temperatures in figure 17 shows a sharp temperature increase below 30 feet (9 m) which is presumed to be the effective depth of penetration by the previous winter's cold, as of 6 September 1961. Generally the density of firn systematically increases downward in a firn-pack, except for irregularities imposed by zones of depth-boar, diagenetic ice, or annual ablation surfaces. In a temperate glacier (in-ice temperature 0°C), 19 the boring rate of an ehxfirothermal drill would be expected to decrease gradually, as a function of progressive density increase as it descends deeper into the glacier. Curve 3 (Fig. 16) represents this asymptotic increase in density at Site 8A, in September 1961. Curve.A represents the bore- rates in inches per hour (cm/hr) at any given depth in the firn, and hence reveals that the initial boring rates between about 5 and 39 feet (2 and 12 m) are less than the boring rates between depths of 39 and 58 feet (12 and 18 m). This seemingly anomalous situation is best explained by reference to the englacial temperature plot in figure 17. Here the slower bore-rates may be attributed to the affects of retained winter chill (eSpecially between about 10 - 30 feet (3 - 9 m). On first examination one is tempted to conclude that lower ice temperatures would more rapidly conduct the heat away from the drill bit, hence slowing the rate. However, because it~takes only 0.5 calorie to raise the temperature of ice 1°C and because the subfreezing englacial temperatures are so slight (as shown in figure 17), in this case the chill zone may be concluded to affect the 1 Miller (1952b) shows that drill rate in some other way. the impediment of drilling through a relic cold zone is not necessarily attributed to the loss of heat alone. Instead the colder firn surrounding a borer may create a freezing condition along the unheated upper portion of a 1It is mentioned that Andress (1962) and Miller (1963) also discuss this phenomenom. .Andress and the writer worked together on this phase of the field work. 20 bore shaft causing some of the loose, partially-melted firn and snow to stick to the shaft and thereby to increase its frictional drag. Below ho feet (12 m) down to about 65 feet (20 m)(Fig. 16) a relatively higher bore-rate suggests that the cold zone was penetrated. Temperatures below 50 feet (15 m) (Fig. 17) vary between -0.10°C and -0.05°C also reflecting the attenuation of the cold zone at greater depth. However, as seen at the base of the figure 1? curve at a depth of 120-130 feet (36-h2 m), a slightly lower temperature reading was made. This is interpreted as a relic cold zone from a severe winter long ago. Corroborating these actual measure- ments of noticeable temperature depressions at 30 feet (9 m) and 120-130 feet (36-39 m) is the previously discussed freezing-in of the suSpension rope at these same three places or close within these zones; i.e., at 30 feet (9 m), 120 feet (36 m), and 130 feet (39 m). ‘Again note the relationship depicted in figure 17. ' Comparison of the englacial temperatures in Bore Hole No. 1 and No. 2 at Camp 83 reveals a similar trend, although Hole No. 2 (hand-angered hole) showed slightly higher tempera- tures. The difference is attributed to differences in the sizes of the bore holes. The hand auger had a bit diameter of 3 inches (7.6 cm), but the hole was enlarged to about 5 inches (12;? cm) by abrasion and peripheral compaction caused by drill rotation and the moving of drill tools in and out of the hole. Bore Hole No. 1 had an almost constant 21 2-inch (5 cm) diameter from the electrothermal bore. .A larger hole allows more air circulation and poorer ice/ thermistor contacts than in a smaller hole. For this reason the thermistor readings taken in the 151-foot (36 m) electrothermal hole are deemed more reliable. All temperature measurements below the t0p of the bore holes to a depth of 151 feet (M6 m) were subfreezing. There- fore, on the basis of the writer's previous discussion of similarity in climatic regimes on these adjoining névés, the upper Taku and Vaughan Lewis névés are both probably subtemperate. The significance of this interpretation and the need for further measurements of this kind directly on the Vaughan Lewis nevi will be considered at the end of this presentation. b. The Icefall Zone .An arbitrary criterion for denoting the tap of the ice- fall is that point where the tension crevasses are seen with their downglacier walls lower than their upglacier walls. In effect this is where vertical shear-strain is firSt noted. For the period of this study, this point is identified at an elevation of about 5500 feet (1675 m) (Fig. 20). The bottom of the icefall is arbitrarily-taken .t'.b..t u000 feet (1225 m), which is the lowest point immediately upglacler from the first undisputed wave-band. The line of this depression is easily seen in the photograph of figure 2, and is diagrammatically noted at the-hOOO-foot contour position in figure 20. THE 22 As the ice moves downglacier from the 5500-foot (1675 m) contour, larger crevasses develop and eventually the slape steepens with the glacier's surface virtually disintegrating into a zone of seracs and ice pinnacles. .Although crevasses near the tap of the icefall were generally arcuate and long and wide, none were seen to have survived this disintegrating movement within the icefall. Near the 1963 seasonal névé-line at thO-h500 feet (1350-1375 m), a distinct change in the type of surface movement was noted. The lack of transverse crevasses in this zone, during the field studies of 1961 and 1963 and also during the aerial photographic examinations, indicates a lack of extending and a dominance of compressive flow. In August, 1961, a significant structure in the ice was observed just below the névéLline. This structure was a distinct isoclinal, recumbent anticline, comprised of bubbly glacier ice and*serving as strong evidence of compression (Fig. 18). .An examination of similar folds was made and logged during, the 1961 field season. A,descriptlon of this phenomenon follows, starting with the first ice fold; i.e., the highest in the icefall, at an elevation of about thO feet (1350 m). Nine ice folds were counted in the icefall and are depicted as Fsl to F-9 in figure 20. Most of these were continuous although F;3, F-6, and F-8 were segmented or discontinuous at the surface. The reader is urged to note again the photo- graphic view of these features so well shown in figure 2. 23 Ice fold F-l lies at the bottom of the highly seracced zone of transverse crevasses depicted in figure 20. This fold was actually hardly discernable among the maze of seracs, some of which rest on its surface. It extended across the entire width of the glacier, about one-third mile (one-half km), and had an amplitude of about 10 feet (3 m) and a width of about 20 feet (6 m). On the crest of this fold, near its north end, several shallow crevasses were found, resulting from the lateral expansion of the ice as it emerged from.the narrow rock defile through which the icefall flowed. These crevasses lay in a radial pattern and characterized each of the folds in Sector 3. Here, also, englacial foliation along the crevasse walls was found to be nearly vertical. Fold F-Z was similar to F-l but with an amplitude of about 12 feet (3.6 m). It, too, was continuous across glacier with a few more shallow radial crevasses on both its north and south ends. Here again along the crevasse walls, foliation was found to be nearly vertical. Fold F-3 consisted of three segments in line across glacier, each of which is depicted in the schematic repre- sentation. The amplitude of each segment was about 10 feet (3 m). These folds had the appearance of symmetrical double plunging anticlines, a characteristic- which is difficult to see until virtually standing on top of them. Fold F-u was considerably larger than those previously noted. This one had an amplitude of 20 to 25 feet (6 to 8 m) and was about 100 feet (30 m) wide, and extended continuously 2h across glacier. On its crest were a few remnant seracs carried down from the seracced and crevassed zone above. On the north end of F—h, part of the ice had fallen away at the time of the 1963 observations eXposing a clean cross- sectional view of the fold. The fold was close to the position of the overfold photographed in 1961 (Fig. 18). As in the earlier observation this ice had folded, without visible fracturing, into a recumbent anticlinal structure. Fold F-5 was measured to be about 50 feet (15 m) wide and was found to be continuous across glacier. Radial crevasses were more numerous indicating a relatively greater lateral eXpansion of the ice. Foliation along the crevasse walls dipped downglacier near the surface and at depth was nearly vertical. Between Fold F-5 and F-6 an inlay of white, fine-grained, non-foliated ice was founde-hereafter referred to as a "white- ice layer.” The white-ice layer between these folds was about 12 feet (3.6 m) wide and was composed of fine-grained glacier ice, from a distance looking more like granular firn. On both sides this inlay had sharp contacts with the coarsely- grained, foliated bubbly glacier ice of the main~ice body, thus giving a characteristic dike-like appearance. Fold F-6 appeared to consist of two intermediate size segments each extending over one-half the glacier's width. These may possibly have represented two distinct folds. The two segments were widest, 80 to 100 feet (25 to 30 m), at the margin of the glacier and narrowest where they pinched out at 25 the center. From the margin to the center these structures resembled plunging anticlines with overlapping ends. Foliation, as observed along the radial crevasse walls, was seen to be much contorted and to dip both up and downglacier. A.white- ice layer, similar to that described above and about 10 feet (3 m) wide,extended across about one-half the width of the glacier between Folds F—6 and F-7. Again it is mentioned that this white-ice layer had no apparent foliation. Fold F-7 was another continuous structure with an ampli- tude of 10 to 15 feet (3 to 5 m). Radial crevassing was even more prominent in this case; and the foliation was expressed on each crevasse wall as a pattern radiating hub-like from a point below the surface, but each folium always dipped upglacier. Fold F-8,similar to F-3, consisted of three segments separated by white-ice layers. The white-ice inlays were notably wide between the plunging ends of each segment. This pattern is considered to be significant and will be discussed later. Fold F-9 was the largest fold of all, being 125 to 150 feet (38 to 35 m) wide and with an amplitude of about 30 feet (9 m). It was also continuous across glacier. What is designeted here as fold segment F-9a was seen as a rela- tively small structure about 160 feet (50 m) long and 15 feet (5 m) wide. Winter snow retained-in an elongated sur- face depression below F-9 and south of F-9a prohibited the examination of the area between Fold F-9 and wave-Band 1 (we-1) in figure 20. 26 c. The Wave—Band Zone The most striking morphologic feature of the Vaughan Lewis Glacier is the series of wave-bands which characterize Sector C (Fig. 21). In general, wave-bands or wave-ogives, as they pr0per1y might be termed (see glossary at end of 'paper), in plan view are seen as a series of hyperbolic- shaped structures having a wave-like cross-sectional surface, usually best develOped on the apron at the base of icefalls. Downglacier these surface waves attenuate and the two-dimensional ogive patterns accentuate. In the case of the Vaughan Lewis Glacier the wave- bands have exceptional amplitude. The magnitude of this amplitude is not fully appreciated until one descends to the glacier apron and sees the wave-bands from the side (Fig. 2). The apparent amplitude (Fig. 22) varies from 80 feetf(25 m) at the base of the icefall and decreases downglacier to 0 at a point about 1.5 miles (2.5'km) below the icefall. The maximum true amplitude may-be as much as half the values indicated in figure 22. The wave length of the bands varies from 300 to 500 feet (90 to 150 m). Five of the bands were measured and their average wave length computed at about uOO feet (120 m). In figure 22 the surfaee profile of wave-bands l - 5 is shown. This figure was constructed from measurements obtained with a hand level and a lOO-foot.(30 m) tape during the 1963 field season. A brief description of these five wave-bands is given below. It is pointed out 27 that snow that has drifted into the swale between the bulges of the wave-bands obscured their true amplitude and precluded observation of the ice lying below the snow cover. Wave-Band WB-l in figure 22 designates the first large band at the foot of the icefall. The height of the band from the swale on the upglacier side was about u5 feet (1h m), and on the downglacier side about 80 feet (25 m) (Fig. 22). Within WB-l, and outcr0pping on its surface, were many white-ice layers (Fig. 19). These were much narrower than those between the folds in the icefall, and were 1 to 3 feet (0.3 to l m) wide and up to several hundred feet (meters) long. .Sometimes they extended across the entire glacier's width. They stood above the glacier's surface about 1.5 feet (0.5 m) as a result of differential ablation produced essentially by the difference in albedo between the white-ice and the coarse bubbly glacier ice of the band. It was observed on many of the waveLbands that two separate white-ice layers, as seen on the surface, would join and continue as a single white-ice layer. .Along a crevasse wall, which cut through the junction of these joining white-ice layers, it was also noted that the separate layers dipped in apposite directions. The pertinent geometric relationships are depicted in figures 23 and 2h, with respect to Wave—Bands WB-2 and WB-h. The appearance in many instances was of an eroded anticline. Thus, these features are hereafter called "white-ice anticlines.” In several places the white-ice layers of white-ice anticlines 28 were seen to join in more than one place giving, in plan view, a canoe-shaped pattern. During the 1961 field season, ice cores were taken with a hand auger from both a white-ice layer and from the coarse-grained bubbly glacier ice. Cores at depths of 3.3 feet (1 m) in the white-ice layers were found to be smooth and relatively unbroken. Conversely, the bubbly ice cores were short, rough and broken into short monocular segments of one-half to two—inch (1.3 to 5 cm) thickness (Fig. 25). The short monocular segments broke along the foliation planes in the bubbly ice. Seven idhite-ice layers were counted on WB-l and they penetrated into the ice as far as could be seen into a 50-to 60-foot (15 to 18 m) deep crevasse. The strike of the foliation followed the curved trend of the wave-band, and in most places the folia dipped upglacier. Wave-Band WB-2 as noted in figures 21 and 22 was another large band with an upglacier height of about 25 feet (8 m) and a downglacier height of about 50 feet (15 m). Its maximum width at the glacier center was h80 feet (135 m). White-ice layers on this band were long and continuous. Measurements were made on the dip of the master folia and the white-ice layers along a crevasse wall (cross-sectional view shown in Fig. 23). These structures generally dipped upglacier except in the area of the white-ice. Wave-Band WB-3 had an upglacier and downglacier height of about 20 feet (6 m) and a width of about hOO feet (120 m) (again see Figs. 21 and 22). Two white-ice layers on the 29 upglacier side of the band extended more than one-half the glacier's width. Wave-Band WB-h had an anomalous cross-sectional form, in that the amplitude on its upglacier side was higher than on its downglacier side. The relationship is shown in figure 22. In addition, the swale upglacier from WB-h is lower than the swale on its downglacier side. .Attention is drawn to this, as usually each successive swale downglacier is lower than the preceding one. Because of this there was ponding of a large volume of meltwater behind WB-h and deviation of a medial drainage channel toward the margin of the glacier (Fig. 2). The anomalous pattern of amplitudes described above could reflect a significant change in bottom topography below the icefall, although also it could connote stress variations in time.1 The sketch of the white-ice layers and foliation given in cross-section in figure 2h shows a case of dominantly vertical or steep upglacier dips. As in the inset sketch of figure 23, this figure also shows a diagrammatic view of the white-ice layers in plan. Here the two vertical white-ice layers strike along the surface parallel to the curve of the wave-band and join each other, suggesting a symmetrical anticline. LA recent preliminary seismic profile below the icefall has indicated that there is indeed a low yet definite bed- rock threshold below the area of Wave-Bands Nos. u 5 5 (Kittredge, 1965; and Miller, 1966). ‘- 30 Wave-Band WB-5 (Figs. 21 and 22)was more like the other wave-bands with a higher downglacier side of 15 feet (u.5 m) than the upglacier side of 10 feet (3 m). It had a width at the center of 350 feet (105 In). There were four white- ice layers on the upglacier flank. Foliation parallekm this band and generally dipped upglacier. W3-5 was the last of the wave-bands on which hand-level measurements were obtained. From this point to the terminus only descriptive field notes were made. Downglacier from WB-S the wave-bands rapidly lost amplitude. Wave—Bands 6 to 15 in Sector C all exhibited white-ice layers. Almost all of the white-ice layers were on the upglacier flank of the swell. .At Wave-Band 15 the crest or leading edge of the wave-band became the dark part of an ogive. The trailing side and trough became the light part of an ogive. d. The Ogive Zone .This sector includes that part of the glacier from Ogive 16 through Ogive 67. .As noted in the glossary, ogives (Forbes' bands) are similar to wave-bands in plan view, but do not have significant surface amplitude. They are alter- nating light and dark areas of ice, generally ogive-shaped but changing shape with the change in stress and type of glacier flow prevailing at the surface. In this zone the vaughan Lewis Glaciertmsaiesnsistently sloping surface of about 3°35' downglacier over a distance of about six miles (9.5 km). 31 Observation of the light and dark parts of the ogives revealed that the dark part never had any white-ice layers. The whiteLice layerShmme always in the light part of the ogive andwere observed all the way to Ogive 67 near the terminus. For the present interpretations this is a very significant observation, as will be shown. In a few instances the white-ice layers were foliated but they were generally non-foliated. Differential ablation on the dark part of the ogive resulted in a humpy surface, with the humps being quite irregular in form and a foot (0.3 m) or less in height. .A greater amount of dirt was observed on the ice on the upglacier side of these humps. The dirt material was not of large particle size on the ogives, except for one large boulder about 10 feet (3 m) high by 6 feet (2 m) long which is considered to be an erratic. Most of the debris was sand size or smaller. The texture of the bubbly glacier ice itself was relatively coarse, with individual ice crystals attaining centimeter size. No distinction could be made between the light and dark part of ogives, except for the above-noted white-ice layers being restricted to the light part_of the ogives. A,study was made of a set of U. S. Navy vertical aerial photographs taken of the glacier 11 July 19h8 one of which is shown in figure 3. On these photographs Ogive 16 had nearly equal areas of light and dark, while farther down- glacier the white part of the ogives had over twice the 32 surface area of the dark parts. .Also surface movements are reflected by changes in plan shape of the ogives as they move\downglacier. For example, when the wave-bands first emerge from the base of the icefall, they are ring-shaped and have a radius of curvature of about 900 feet (275 m). When they have moved about 7 miles (11 km) from the base of the icefall, they become as pointed arches (ogives) and have a radius of curvature of at least 6500 feet (1975 m). This is, of course, empirical evidence of a streaming type of flow or mode of mass movement. e. Terminal Sector Ogive 67 was the last recognizable ogive because of the large number of crevasses resulting from the flow of the glacier into side valleys (Fig. 3). Parts of ogives beyond 67 can be seen, however, so the total number of wave- bands and their downglacier counterparts, the ogives, is set at approximately 73. If these structures have time significance such a statistic can be important. In view of the drainage into the ice-dammed lakes shown in figures 3 and h, and because the vaughan Lewis-Gilkey Glacier complex is the main valley glacier system in this sector of the icefield, one might ask the question are the side valleys near the dual terminus lower than the Vaughan Lewis Glacier. The answer appears to lie in the self- dumping character of these lakes (Miller, 1952a), an annual event which could not take place if the side valley floors 33 were lower than the valley floor of the Vaughan Lewis-Gilkey Glacier complex. Thus it is only the Vaughan Lewis Glacier's ice surface which is higher. In other words these are hanging side valleys with their outlets at present blocked by ice. Therefore, the lower part of the Vaughan Lewis Glacier may be presumed to continue to flow along the main valley while only a portion of its upper part sloughs off into the referenced side valleys (Freers, 1965b). With respect to the periodic drainage of the ice-dammed lakes at the Vaughan Lewis termini the release of water is catastrophic, and takes place usually before mid-summer, via englacial and/or subglacial outlets. Detailed studies have not yet been made of this interesting phenomenon. 3. Néve-Line Characteristics and Positions Long-term changes in mean nave-line position are one of the useful indicators of a glacier's regime; but these changes should be interpreted together with stratigraphic information from the nave (Egan, 1965). The annual late summer position of the neveclinel is affected by many factors-~the most important of which are the amdunt of net retained accumulation, the length of the effective ablation season, and the orographical relationship, including the 1Referred to in J. I. R. P. reports as the seasonal neve- -line (Miller, 1963). The mean neve-line represents the average position over the latest decade. 33 glacier's size and gradient within the area of the névé-line's short-term variations. .As far as the glacier'stotal mass budget is concerned, the morphology, orientation, and area elevation factors must also be considered. On the Vaughan Lewis Glacier these considerations are of unique concern because the icefall and its basal apron may be considered to lie within a zone of maximum neve; line variation; i.e., from 3500 to 5300 feet (1075 to 1650 m). The U. S. Navy aerial photographs, taken on 11 July 1938, reveal the midsummer transient neveeline on the Vaughan Lewis Glacier to be well up within the icefall, at 3300 to 3500 feet (1350 to 1380 m); while on the adjacent Gilkey Glacier to the north, and the unnamed tributary merging with the Vaughan Lewis Glacier from the south, the nEVE-line rested somewhat lower respectively at about 3200 feet (1275 m) and 3100 feet (1250 m). .A similar difference in nevi-line elevations has been observed on these glaciers in subsequent years. It is of interest, therefore, that the Vaughan Lewis Glacier rises abruptly from Sector C, through the rock-bordered icefall (Sector 3) for about 1500 feet (350 m). Therefore, the effects of bedrock radiation as well as sunlight are less on the upper Gilkey Glacier where a gentler gradient and different orientation pertain (Fig. 3). Thus, confinement, morphology, gradient, and orientation seem to be the critical geographical factors in the nEVe-line positions of these adjacent glaciers. 35 The 1961 to 1963 seasonal néVE-line positions on the Vaughan Lewis Glacier were observed in late September of each year. Observations in 1963 placed the final seasonal nEVE-line position at about 395 feet (1203 m) due in part to a short ablation season (Miller, personal communication). This is the lowest on record also for the Taku Glacier as shown by the following table of comparisons. From J.I.R.P. records (Egan,l965b; and Miller, 1963 and,.1966) the positions since 1956 are also noted. This decade of record provides a basis for a mean névé-line determination. .Approximate Seasonal NévE-Line Positions on Vaughan Lewis and Taku Glaciers Over the Past Ten Years Vaughan Lewis Glacier Taku Glacier Feet Meters Feet Meters 1965 3100 1250 2800 853 1963 39501 1203 2350 737 1963 3350 1356 3000 913 1962 3200 1280 2950‘ 900 1961 3300 1331 2900 885 1960 3500 1372 3100 935 1959 3300 (est.)i 1331 3000 913 1958 3300 1311 3000 913 1957 3600 (est. ) 1302 3200 975 1956 3600 (est. )‘ 1302 3200 975 The five-year mean for the Vaughan Lewis nEVeLline position for the years 1961 to 1965 is about 3200 feet (1280 m), as opposed to about 2800 feet (853 m) on the Taku Glacierow The mean nave-line for the Vaughan Lewis Glacier over the past decade is approximately 3350 feet (1325 m); for the Taku Glacier, 2960 feet (903 m). Even though the 1Estimated from tabulated difference in known years, as well as from.Taku and Lemon Glacier neve- line trends (J. 1. R. P. ) 36 last several years have proved to be exceptionally positive in the regime sense (Egan, 1965b), and even though the current trend is toward a lowered névé-line, this still places the seasonal névé-line several hundred feet above the base of the Vaughan Lewis Icefall. Thus, within the range of present climatic pulsations even in abnormal years the wave-bands have been well eXposed at the end of summer. Using 3200 feet (1280 m) on the cumulative area-elevation graph (Fig. 5) as the average neve-line position for the present decade (i.e., since 1960), the area of the ablation zone is seen as 2.93 square miles (7.37 sq km) and the accumulation zone as 6.08 square miles (15.2 sq km). Thus, about a 2 to l accumulation- ablation area ratio pertains on the Vaughan Lewis Glacier. The Vaughan Lewis Glacier's total area is 9.02 square miles (25.07 sq km). The comparison with reSpect to the cumulative area-elevation characteristics, as previously noted, is given in figure 5. The mean nEVe-line positions of each glacier are also compared on this figure. That for the Taku Glacier, however, has been figured from the past 20 years of observation rather than only since 1956, as given in the foregoing table. This longer-term value is therefore cited, giving a mean position of 3000 feet (913 m). This means a 1200-to 1500-foot (365-396 m) lower nevé-line on the Taku Glacier than on the Vaughan Lewis Glacier. .Again, the difference is ascribed to the oro- graphical and geographical factors discussed. 37 On the Taku Glacier, the mean néve-line position on the graph indicates a lower glacier ablation zone of about 30 square miles (75 sq km) and a névé accumulation area of about 185 square miles (363 sq km). The result is an accumulation-ablation area ratio of 6 to l for the Taku Glacier compared with the 2 to 1 ratio on the Vaughan Lewis Glacier. Therefore, the fluctuation regimes of these two glaciers cannot be compared without detailed consideration of their area-elevation statistics-~an analysis clearly beyond the sCOpe of the present study. It is readily seen from this, however, that a considerably greater ablation relative to accumulation is to be eXpected on the Vaughan Lewis Glacier than on the Taku Glacier. Hence the lower glacier englacial structures on the vaughan Lewis Glacier should be expected to be exceptionally well exposed as, of course, has been amply illustrated in figures 2 and 3. 3, Surface Movement Records a. Surveyed Observations Measurements were made of the surface movement on the Vaughan Lewis Glacier during the summers of 1961, 1963, 1963, and 1965. The 1963 survey records, however, were obtained by Haves (1965); with supplementary mapping and geophysical data obtained in 1963 and 1965 by Kittredge (1965 and 1966).1 A.pattern of movement stakes was 7' 1The latest report by Kittredge is not discussed in this presentation as it Came to the writer's attention during the final typing of this manuscript. 38 initially established on the wave-bands in August 1961. These are shown in figure 26 with surface velocities and directions indicated. A.series of readings were made on prominent seracs and ice pinnacles in the icefall for purposes of comparison with the stake information as it was, of course, impossible to place stakes in the icefall. .A l38-foot (32 m) base line was established on a ridge adjacent to the foot of the icefall (Fig. 26). In 1961, the readings were taken from each end of the base line on each_stake (designated as F in the figure); and on the seracs, or ice pinnacles (designated as P-in the figures). Upon analysis of the data, some exceptionally high velocities were computed, as indicated on stakes F-l through F-6. This suggests either errors in measurement or unexpected conditions in the glacier below the icefall (see footnote regarding data for these movement stakes in Appendix H, Part 1). The results are included in Appendix H, Part 1, for future comparison. Some of the data, however, appear reasonable as do the relative movement values. For example, the relative movement between stakes F-l, F-2, and F-3 gives 20.8 feet (6.3 m) per day, 35.8 feet (13.0 m) per day, and 35.8 feet (10.9 m) per day. .As absolute values, these statistics may be Open to doubt, but as ratios they are not unreasonable. It is considered that the absolute readings are probably in error as the theodolite sights 'were made at distances of a mile or more, and almost directly along the line of stake movement. 39 The readings on stakes F-7 through F-ll, and on seracs P-l through P-3 and P-6 through P-8, give more favorable results (Appendix H, Part 2).' These summer velocities fall within the limits of glacier movement expected when compared with data on comparable icefalls elsewhere, as discussed below. From the measurements it is noted that no velocities were greater than 7.3 feet (2.3 m) per day for the movement stakes in the wave-band zone (Sector C), or 13.3 feet (3.1 m) per day for the ice pinnacles in the icefall (Sector 3). 3y projecting these summer velocities to a minimum annual figure, the pinnacles P-2 and P-3 would give respectively 2200 feet (670 m) per year and 3300 feet (1310 m) per year. These values are comparable to those cited by King and Lewis (1961) on the orographically similar icefall of the Odinsbreen and.Austerdalsbreen in Norway; i.e., where velocities of over 3000 feet (913 m) per year have been reported. The direction and magnitude of the movement vectors P-2 and P-3 corroborate the previous interpretations of extension flow in the upper part of the icefall. A.striking contrast in movement of the upper icefall segment compared with the lower segment is shown by the plotted vectors for the bottom half of the icefall (Fig. 26). Ice pinnacles P-1, P-6, P-7, and P-8 show movement in a direction almost perpendicular to the expected longitudinal flow direction of the glacier. This is explained by two considerations: (1) the change of movement from extension 30 to compression flow, as expressed by the closure of crevasses and the deve10pment of ice folds; and (2) the emergence of ice from the narrow defile valley of the icefall spillway allowing the lateral expansion of the glacier in its lower apron zone (Sectors 3 and C). Examination of movement stakes F-7 through F-ll (Fig. 26) reveals a similar situation. These vectors indicate that lateral expansion persists as the ice moves down valley. For purposes of discussion, hereafter all movement at right angles to the direction of the base line (Fig. 26) will be termed x-movement. .All movement parallel to the base line--essentially down valley in the Spillway itself-- will be referred to as y-movement. Any movement which is vectorally upward or downward (that is in a direction perpendicular to the plane defined by x and y) will be termed z-movement. These vectoral values are noted in .Appendix H, with reapect to the pertinent data on the 1961 stakes and seracs. No surveys were made on this glacier during the summer of 1962. In 1963, however, the survey stations were occupied and five of the 1961 movement stakes resurveyed. These measurements provide two-year averages for the velocities at these stakes as noted in Part 1 of Appendix H. In this period the average y-movement for the four stakes in the wave-band zone (Sector C, stakes F-8, F-9, F-10, and F-ll) was 13 feet (3.3 m) per day, with the x- movement averaging 1.6 feet (0.5 m) per day. These values 31 are plotted in figure 27, showing the initial 1961 positions, the final 1963 positions, and the average two-year velocity vector in feet per day. The dominance of y-movement indicated by the relative magnitudes in the x and y direction, and also shown by comparing the vector directions plotted in figures 26 and 27, demonstrateShow quickly lateral expansion dissipated the deformation effects as ice passed through the main apron sector during this two-year interval. During the 1963 field season, movement measurements were made on the Vaughan Lewis Glacier by Havas (1965) (Appendix I). The magnitude of movement near the foot of the icefall first decreases from about 1.38 feet (0.32 m) per day to 1.15 feet (0.35 m) per day and then increases to 1.38 feet (0.32 m) per day (Fig. 28). b. Strain-Rate Analysis In 1963 strain-rate measurements were made on the seventh wave-band, using a strain diamond on the crest (Fig. 28). Strain-rates were also determined in this year between movement stakes 7 and 8 (Havas, 1965). HavaS' analysis of the movement data,in terms of strain-rates in the strain diamond and movement ratio on stakes 7 and 8, shows reasonable agreement. In addition Havas shows that there are compressive stresses at and below the base of the icefall and tensile stresses farther downglacier in the vicinity of movement stakes 7 and 8. This agrees with the 32 structural interpretation given in the following section. Also these data have significant bearing on the inter- pretation of the develOpment of wave-bands to be considered in the summary chapter. c. Structural Analysis Crevasse patterns on a glacier are a reflection of the tensional, compressive and shear stresses in the upper part of a glacier. Analysis of crevasse patterns and other structural shapes can also tell us much about the type of flow occurring at a glacier's surface--particularly whether it is Block-Schollen or streaming flow (Miller, 1958), and extending or compressive flow. Nye (1952) has shown that transverse crevasses form during extending flow but not during compressive flow. He also shows that the shear stresses found at the margin of a glacier will, during compressive flow, form crevasses of less than 35 degrees with the valley wall. During extending flow, the shear stresses will form crevasses at an angle of 35 degrees with the valley wall, and pointing upglacier. .A longi- tudinal compressive stress could be caused by ablation, a concave bed, narrowing of the glacier valley, or movement around a topographic bend in a glacier. Similarly, a longitudinal tension can be caused by accumulation, a con- vex bed, widening of the valley, or by movement around the outside of a bend in the glacier. 1+3 The vaughan Lewis-Gilkey Glacier complex (Fig. u) involves all of the above mentioned types of flow. :ln a more descriptive sense these are alluded to as streaming (parabolic in plan view), Block-shollen (rectilinear in plan view), and composite (combining both of these geometric forms). .As pointed out in earlier J.l.R.P. reports (e.g., Miller, 1963), streaming flow connotes maximum relative movement within the ice and Block-Schoilen flow connotes maximum basal and marginal slippage. Thus, the structural configurations of the ogives in the lower glacier area may be diagnostic. The icefall of the Vaughan Lewis Glacier has many transverse crevasses due to a narrowing of the valley and the steepness of the sIOpe. In the lower one-third of the icefall, the transverse crevasses are replaced by many radiating crevasses due to the widening of the valley and the compressive build-up of ice in the apron area. It is reiterated that these structural patterns reflect the type of stress at the surface--dominantly tensile in the upper two-thirds of the icefall and compressive in the lower one-third, a fact corroborated by Havas' strain-tensor analyses.) The plan view of wave-bands as they are formed at the base of the icefall is symmetrically hyperbolic (streaming). This shape rapidly changes as the ice moves downglacier and as ablation effects dominate, resulting eventually in the display of pointed or ogive shapes. Crevasses along the uh valley wall in the lower glacier section indicate the move- ment of the glacier to be mostly extension flow--a fact again corroborated by Havas' strain-tensor analyses. In the terminal sector, the glacier takes a sharp turn into the two low side valleys previously described, and well shown in figures 3 and u. The result here is an extreme extension flow corroborated by the presence of a multitude of transverse tension crevasses. In summary, the general movement of the vaughan Lewis Glacier is by extending flow in the upper part of the icefall and by compressive flow in the lower part of the icefall and in the first mile (1.5 km) below the icefall. Ogive shapes indicate a streaming flow in the lower valley section from the first to last ogives. Thus the main mode of mass transfer in this glacier is concluded to be essentially a streaming type of flow (Freers, 1965b). .A comparison with the Taku and other glaciers in the region bears out the regime significance of this interpretation. II. COMPARISON WITH OBSERVATIONS ON THE TAKU AND OTHER JUNEAU ICEFIELD GLACIERS During 1961 and 1963 movement measurements and related stratigraphic studies and observations were made on adjoin- ing glaciers of the Juneau Icefield. These are abetted by previous and subsequent J.I.R.P. data. .A brief comparison is made with respect to the vaughan Lewis Glacier measure- ments which have been described. The statistics discussed below emphasize the particular measurements in which the writer was involved during the 1961 field season. Higher Taku NEVe Stratigraphy for the Camp 8, 6000-foot (1825 m) névé of the Taku Glacier has already been discussed (Figs. 12 and 13) in conjunction with the Vaughan Lewis Glacier stratigraphy. Movement measurements on Profile VIII (Fig. 1), extending from Camp 8 to the have divide between the Taku and vaughan Lewis Glaciers, were made in 1961 as a supplement to the summer of 1960 surveys by McLane (1960, and personal communication) (Part I,.Appendix J). The velocity profiles for 1960 and l96l are plotted-in figure 29. These velocities, as will be seen, are considerably less than the velocities found on the lower level cross- glacier transects in the Camp 9 and Camp 10 sectors. The maximum velocity measured in 1960 on the Camp 8 profile was 0.9 feet (0.3 m) per day and in 1961 it was 0.55 feet " 'Lis us (0.2 m) per day. .Also the shapes of these curves are much flatter than shown in the two graphs (Figs. 30 and 31) for the lower névés of the Taku Glacier. It should be noted that the Camp 8 profile is distinctly of streaming or shallow hyperbolic form, indicating dominance of englacial flow rather than maximum basal slippage effect. This is comparable to the lower Vaughan Lewis Glacier case. Intermediate Taku Nevé In 1961 no stratigraphic studies were carried out by the writer at the Camp 9 nave, which lies at approximately 5000 feet (1525 m). Surface movement measurements in Profile VII (Fig. 1 and Appendix K), however, were made and are plotted graphically in figure 30. Here the direction of the transect is westerly with the shape of the flow curve being intermediate between that cited for the upper néve and that for the Camp 10 (lower nevé) sector described below. These velocities are greater, than on the crestal hive, with a maximum of 1.2 feet (0.h m) per day expressed at the center of the glacier. It is interesting that the shape of this curve is comparable to the shape of the first wave-band on the Vaughan Lewis Glacier (Fig. 21). This wave-band may be presumed to reflect more dominantly surface movement than it does movement at depth. Lower Taku Néve In 1961 surface movement measurements were conducted by the writer, in company with D. Bingham, on the 3500-foot h? (1075 m) n§v€ along a line (Profile IV, Fig. 1) extending westerly across the glacier from Camp 10 (Fig. 31). These measurements reveal an average daily movement in the center of 2.1 feet (0.6 m) per day in 1961 compared with 2.5 feet (0.8 m) per day based on the 1960 survey (Appendix L). Supplemental to these records, net accumulation measurements were also made along a crevasse wall at the position noted in figure 31. The results of these measure- ments are given in.Andress (1962) and are plotted in figure 13 for comparison with Site 8A. These show a net of 5.7 feet (1.7 m) of 1960-61 retained accumulation. The bulk density was 0.60 which approximates the late-summer firn density. From this may be compiled a positive accumulation of 3.h feet (1.0 m) (water equivalent) which is deemed representative for the lower n5ve at this elevation. With respect to the Vaughan—Lewis Glacier study, these lower Taku névé regime and movement data reveal two points of interest. First, the annual retained accumulation in 1961 is seen to be substantially positive at 3500 feet (1075 m) elevation on the Taku Glacier, but is negative at a comparable elevation on the Vaughan Lewis Glacier, as the 3500-foot level was 700 feet (210 m) below the seasonal névé line in that year. Secondly, the surface movement on the Taku Glacier on Profile IV'(Camp 10 Sector) is not streaming, but a true Block»Schollen profile, indicating dominance of basal sliding. On the Vaughan Lewis Glacier in contrast, the maximum.mass transfer is considered to be en- glacial. A8 Other Banded Glaciers on the Juneau Icefield Many icefall glaciers flow from the periphery of the Juneau Icefield and at least 20 of these glaciers exhibit banding such as ogives or wave-bands (Miller, 19523.). To mention a few, for example the Battle Glacier (Fig. n) has wave-bands with a minimum of amplitude. However, the ogives are excellent examples, being distinct and persisting to the Junction with the Gilkey Glacier. The Herbert and Mendenhall Glaciers also exhibit prominent wave-bands and ogives, similar to those on the Vaughan Lewis Glacier. The East and West Twin Glaciers, near Taku Fiord,also have excellent exposures of wave-bands and ogives, with the best examples on the East Twin Glacier (Leighton, 1951, and Miller, 1952a). However, the shape in plan view of these ogives is distinctly different from the ogives and wave- bands of the Vaughan Lewis Glacier. The main distinction is that the Vaughan Lewis Glacier wave-bands emerge from the icefall as smooth hyperbolic curves and then rapidly deform to pointed arches or ogives. The East Twin Glacier ogives, in contrast,retain a more rounded, ring-like pattern all the way to its terminus. The significance of these differences may be important as revealing trends in overall regime of these separate glaciers,as will be explained later. III. WORKING HYPOTHESIS ON WAVE-BANDS OF THE VAUGHAN LEWIS GLACIER Other Theories Louis Agassiz was the first to use the term ogive for the structures of the type here discussed (Agassiz, l8u7). Since that time a number of other terms have been applied-- including such as dirt bands (Forbes, 18h2), Forbes' dirt bands (Quincke, 1905; Fisher, 19h2), and periodic annual banding (washburn, 1935). tAlso other features have been called ogives which have a different structural history (Russell, 1897). In the course of such earlier investi- gations a number of theories and hypotheses have been proposed to explain wave-bands (wave-ogives) and ogives. Several of these theories and hypotheses are now considered as a basis for understanding the hypothesis to be prOposed in the present study of the vaughan Lewis Glacier. 1. Porosity Difference Theogy J. D. Forbes (18h2) proposed that alternating light and dark areas of glaciers having what he called dirt bands are the result of in-ice porosity differences. His con- clusion was that the light part of dirt bands (in the present study, ogives) represents a more porous zone. 2. Primary Stratification Hypothesis Louis Agassiz (18h7) prOposed that ogives are the alternating summer ablation surface and winter snow surface #9 50 exposed by ablation. This hypothesis was supported later by Hess (190A) and by Vareschi (l9h2, also in Godwin, l9h9). Vareschi's support of this concept was based on the difference and abundance of pollen grains which he found in the light and dark part of the ogives. Deformed and some- times arcuate primary stratification structures have also been described by Miller (1952a) with respect to certain banded phenomena on the Juneau Icefield, but these have been carefully distinguished from the ogive-type of structure we are considering here. 3. Serac-Crevasse Hypothesis Observations by Washburn (1935) led him to believe that the dark part of an ogive is the result of dirt in- filling crevasses between seracs in the icefall. The wave of a wave-band he concluded to be a former serac ablated into a smooth round wave. .Another serac-crevasse hypothesis was proposed by Fisher (19h7). The mechanism here discussed is similar to that of Hashburn but instead of dirt accumulating in the crevasses, clean-ice debris gathers in them. The result below the icefall is the clean-ice debris representing lighter parts of the ogive and dirty ice of the serac representing darker parts of the ogive. Fisher also describes QAlaska bands” and attributes them to primary (sedimentary) stratification. 51 h. Shearing_§ypothesis F. B. Leighton (1951) stated that ogives on the East Twin Glacier on the Juneau Icefield, Alaska, are formed by the periodic occurrence of obstructed extrusion flow at the base of an icefall. In essence, he considers that the change in slope of the bedrock causes obstruction of the glacier flow resulting in low-angled shearing. This shearing movement forms transverse pressure ridges which are the wave-bands. The shearing also concentrates en- glacial and subglacial debris at the surface to form the dark part of an ogive. This idea of thrust shearing with respect to the East Twin Glacier was originally reported on (in the l9h9 J.I.R.P. field season report) by Miller (1952a, see Fig. 37 in this report), who also presented some evidence for the annual periodicity of the wave phenomena. 5. Winter-Summer Theory King and Lewis (1961) postulate that thin highly- crevassed ice in theicefall is subjected in summer to crystal changes, infusion of dirt and some freezing of meltwater in crevasses. In the winter, the icefaIl is ”protected” by winter snow. When the summer ice reaches the base of the icefall, it forms the dark part of the ogive and the winter ice forms the light part of the ogive. Fisher (1962) prOposed a similar hypothesis which differs only in that'the winter ice in the icefall is subjected to extreme cold temperature resulting in white 52 bubbly ice. He suggested that the waves are the result of differential ablation due to differences in thermal con- ductivity and greater albedo of the white bubbly ice. 6. Regelation Hypothesis .Atherton (1963) suggests that the dark part of the Ogive is the result of absorption of dust in coarse crystalline ice which formed by regelation on the closure of extension crevasses in the cirque area of icefall glaciers. He further suggests that the coarse crystalline ice is bunched by velocity fluctuations in the glacier at the tap of the icefall. These velocity fluctuations are attenuated by rock steps below the glacier in the icefall zone and this results in the waves of the wave-bands. .. 7. Compression_Hypothesis} Kamb (196k) and Shreve and Kamb (1963) state that waves are generated at the foot of icefalls where the change in sIOpe causes the ice above the base of the ice- fall to slow down to the speed of the ice on the gentler slepe below the icefall. The ice is greatly thinned in the summer and is not thinned as much in the winter as it passes through the icefall. The resulting difference in thickness between summer and winter ice is amplified by the great compression at the base of the icefall producing an annually repeating wave form. .A modification of these ideas is also considered by Kittredge (1966). 53 Discussion With Respect to the Vaughan Lewis Problem (Although many of these hypotheses, or a combination of them, help to explain the genesis of wave-bands and ogives on other glaciers, none of them adequately explains the origin of the wave-bands and ogives on the Vaughan Lewis Glacier. These hypotheses will now be examined in the light of the field observations which have been described on the Vaughan Lewis Glacier. The explanation of the light and dark parts of the ogives via porosity differences is partly true on the Vaughan Lewis Glacier. The light part of the ogives, however, is not composed entirely of fine-grained, white- ice layers, although these are thought to give this part of the ogive its lighter appearance. Also, Forbes (18u2) said the light part is more porous and the dark part less porous. .As detailed porosity observations were not made on the Vaughan Lewis Glacier at the time of this field work, it is difficult at present to state categorically which part of the ogive is more ”porous.” The primary stratification hypothesis seems logical until it is remembered that ogives form only below an icefall. Also, the width of the dark part of the ogives must be considered. Almost all dirty layers in the stratification of firn are less than one foot (0.3 m) thick and normally cannot account for the considerable width which has been found in this case in the dark part of ogives. Primary stratification when exposed at glacier surfaces is generally Sh seen as a system of narrow lines, usually deformed by flow in valley glaciers and accentuated by differential ablation. These are not the smooth hyperbolic curves or pointed ogives with which we are here concerned. Miller (1952a and 19558) has adequately differentiated such morphogenetically different features on the Juneau Icefield. The serac-crevasse hypothesis of Washburn (1935) and Fisher (l9u7) is an unreasonable eXplanation for the wave- bands and ogives of the Vaughan Lewis Glacier for the following reasons. Observations made from above, below, and on the icefall itself, have shown that no crevasse can travel intact from the néve (Sector A) through the spillway (Sector 3) of the icefall (Sector c).’ The great churning action, fracturing, and ablation which take place during the descent completely destroy the crevasses and seracs. Leighton's (1951) and Miller's (1952a) original thrust- shearing hypothesis also appears to be inapplicable, at least to the vaughan Lewis Glacier case, because in spite of a thorough search of the apron and lower glacier surfaces, no evidence of discrete low-angled shearing or of upthrusting of debris could be found. The King and Lewis (1961) winter-summer theory has some merit, although it does not explain the wave-bands themselves. It is possible that the dark part of the ogive may be, in part, the result of dust being blown onto the ice surface during the transit through the icefall in the summer months. Atherton's ”regelation hypothesis” (1963) completely fails to explain the continuous white-ice layers in the 55 Vaughan Lewis Glacier wave-bands. .Also, his suggestion that wave-bands originate within the icefall,by attenuation of velocity fluctuations through the effect of bedrock steps beneath the glacier in the icefall zone, does not eXplain why the Vaughan Lewis Glacier wave-bands are formed only below the icefall. The compression hypothesis of Kamb (l96h) comes closest to fitting the evidence of the present study. In his case, the.Austerdals Glacier in Norway, he depicts the wave-bands as originating in the icefall prOper and shows how brecciated avalanche debris may become incorporated between the wave- bands. This again, however, does not explain the icefolds or white-ice layers described in the Vaughan Lewis Glacier. A modification of the compression concept, however, appears to have merit in the present case. Summary of Results and Conclusion Although the following hypothesis may be far from come plete, it provides what to the writer is a reasonable explanation of the sequence of events which could result in the genesis of the structural features which have been described on the Vaughan Lewis Glacier. It has already been shown that a great deal of compression is present in the glacier in the lower part of its icefall and in the apron area immediately below the icefall. Supporting evidences for this lie in the movement data, the lack of transverse crevasses, the folding of the ice, the lateral expansion of ice, and the overall curvilinear shape of the 56 icefolds and wave-bands. Such compressive flow is reflected in the icefall itself as far as the first fold, which has been described at the lower end of the main transverse or tension crevasses in the icefall. It is believed that the maximum compression, however, occurs farther down lepe, probably at the true base of the icefall at about h000 feet [(1225 m) elevation. It is at this point that the glacier's surface has been deformed upward to relieve the stress of this powerful compression. This rise of the glacier's surface is the bulge of the first wave-band. It is also considered that the maximum stress effect is expressed in late winter or early spring, details of which are yet to be discussed. To recapitulate, certain of the structural features which have been examined suggest an orderly and lagical sequence of events. These features are (I) the white-ice layers and white-ice anticlines on the wave-bands; (2) the folds of ice in the icefall itself; (3) the white-ice layers in the icefall (all of the above in the icefall and wave- band zones Sectors B and C); and (h) the ogives of the lower glacier area, exposed partially in Sector C but mainly in Sector D. The white-ice layers in the wave-bands consist of fineégrained, non-foliated, white-ice and are continuous, sOmetimes extending across the total width of the glacier. This ice is extremely white, with no contamination, and with crystal sizes quite uniform throughout. The white-ice layers between folds in the icefall are similar to the white-ice in the wave-bands, although much wider. The white-ice layers 57 occur between folds F-5 and F-9, while no white-ice layers occur between folds F-l and F-5 (refer again to Fig. 20). The relationship of these white-ice layers is important evidence with respect to the genesis of wave-bands. It is postulated that winter snow is trapped between the ice folds in the icefall during the accumulation season (see cross- sectional views in Fig. 32, Step I). .As these folds move with the glacier toward the base of the icefall, the compression increases thus forcing the icefolds closer together and initiating metamorphosis of the winter snow into fine-grained white-ice (Fig. 32, Step 2). As the folds reach the point of maximum compression at the base of the icefall (see Fig. 32, Step 3, depicting a hypothetical Step 2 segment moved onto a lower gradient section of the ice apron), two or more folds are raised into the initial bulge of a wave-band. Contemporaneous with this deveIOpment, lateral expansion takes place as the glacier emerges from the icefall depths resulting in elongation of and thinning of the white-ice into layers (Fig. 32, Step h). This does not, however, yet explain the white-ice anticlines. The process is the same as described above, but involves a discontinuity in the winter snow cover by protrusion of a small fold segment (see plan views in Fig. 33, Step I). This fold segment (Step 2) becomes enveIOped by the two larger folds resulting in development of a layer on either side of the small fold (Fig. 33, Step 3). These converge at the ends of the small fold into a single white-ice layer. 58 Then, when later elevated into the bulge of a wave-band, this structure resembles an eroded anticline (Fig. 33, Step h). The above explanation shows how the wave-band is com- prised of two or more ice folds, and eXplains the presence of the white-ice layers as inlays within the glacier. .As such, they persist for some distance down valley, eventually being ablated away-~50 that there should be no evidence of them even as relic structures in the terminal zone (Sector E). Examination of the ogives in glaciomorphic Sector D, however, did reveal that some white-ice layers occur in the light part, but few or none in the dark part of the ogives. No difference was noted between the ice crystals or foliation of the light and dark parts of these ogives except where white-ice layers have persited. It is believed that to a considerable extent the light part of the ogive in Sector D is due to presence of the white-ice layers and the dark part to the absence of white-ice layers. At the point of wave-band attenuation, it was noted that the white-ice layers were on the upglacier side of the ‘wave-bands. The transition from wave-band to ogive was subtle between Have-Band 15 and Have-Band (Ogive) 16 (Fig. 21). The leading edge of Have-Band 15 had become the dark part of an ogive and the trough and upglacier side of Wave-Band 16 had become the light part of the ogive. Using all of the above criteria, a hypothesis for the development of these banded structures in the Vaughan Lewis Glacier is presented as a concluding statement in this study 59 (also see Freers, 1965a). It is generally accepted that the lower end of a glacier below the névé-line will move faster in summer than in winter (Sharp, 1951). It is also to be expected that the glacier in its icefall segment thins more by ablation during the summer than during the rest of the year. Therefore, if we make the assumptions that the glacier at the base of its icefall moves slightly faster in summer than in winter, and that accentuated summer ablation results in less ice flowing into the apron area at the base of the icefall, then the least compression at the base of the ice- fall must occur in summer. During the winter the Opposite would pertain; i.e., the greatest compression. Such is reasonable also in that the greatest load (snowfall) would be at the end of winter. Thus the maximum bulge of the- primary wave-band would be formed during and at the end of winter. It is of corroborative interest that between the ice folds F-l through F-5 in figure 20, no white-ice layers were found. This indicates that these folds did indeed form during the ablation season when new snow was not available to incorporate between the developing folds. Folds F-5 through F-9 were observed to have white-ice layers between them and hence are believed to have formed during the previous winter season when much snow was available for incorporation in the depressions between the folds. If any part of the glacier between Folds F-5 and F-9, with white-ice layers between them (Fig. 32), becomes elevated into a wave-band, these white-ice layers will come to 60 represent the light part of a future ogive. Therefore, on this basis one wave-band with its swell and swale, will be formed each year; and the white-ice in this wave-band will represent the winter snow from the previous year. It follows that the 73 identifiable wave-bands in the glacier's total length may represent 73 Years. If true, this suggests that the terminal ice is probably about a century old, and hence that all of the ice and associated structures which have been described are of a correspondingly lesser age. .As discussed earlier, streaming flow is dominant on the lower Vaughan Lewis Glacier. This type of flow suggests a tendency towards a negative regime or negative total mass budget in the glacier. system. This would at first appear in error in view of the healthy néve zone conditions described. However, this can be explained by the previously cited area-elevation comparisons and the 2 to 1 nourishment to wastage ratio on the Vaughan Lewis Glacier versus the 6 to 1 ratio on the Taku Glacier, the latter of which is in a very healthy advancing state at its terminus. If the con- cept of one set of wave-bands produced annually is correct, with the corollary that the total age for the Vaughan Lewis Glacier is 73 Years to a century old, then the glacier's regime,at least oVer the past 73 years has been regressive or negative in total effect. The glacial geological, geomorphic, and geobotanical evidence cited by Beschel and Egan (1965), Miller (1956 and 1963), and Miller and Prather (1965) corroborates this conclusion;and in fact substantiates that this glacier and its neighboring glacier systems have 61 been in a downwasting state for most of the past four centuries. Such a conclusion is in marked contrast to that described elsewhere regarding the past regime of the adjoining Taku Glacier. For such reasons,a complete understanding of the wave-bands and ogive patterns so beautifully displayed in the Vaughan Lewis Glacieg is of greater significance than might be attached to a purely structural interpretation. IV. SUGGESTED.ADDITIONAL INVESTIGATIONS .As pointed out in the last paragraph of the previous chapter, a structural interpretation does not reveal all of the glaciological implications of wave-bands and their associated ogive structures. Further investigations will not only add to the knowledge of glaciotectonics in the structures described, but may also increase the understanding of the glacier's "open system” as related to climatic cycles. To accomplish these aims a sound program of investi- gation should include many techniques, some of which have already been invoked in a continuing study of this phenomenon by the Juneau Icefield Research Program. The technique of terrestial photogrammetry for precise mapping of wave-bands- and surface structures is essential, as there is no more accurate way to record changes of structure, orientation and form of individual wave-bands as they move downglacier. In this regard, motion parallax study of movement in the icefall itself might be rewarding. A.more comprehensive and thorough stress-tensor study at the base of the icefall and on the wave-bands also would clarify the type and magni- tude of stress at the surface of the glacier. In conjunction with these, knowledge of the bedrock topography, determined_ by very detailed geophysical depth soundings ea key“transects, would contribute to the overall information of the character- istics of the physical environment acting on the glacier. ' 62 63 Systematic analysis of entrained particulates, both organic and inorganic, and both in the néve and in the light and dark parts of the wave-bands and ogives,might result in additional evidence with reSpect to the concept of annual pulsation. .A petrofabric analysis of ice cores in the white-ice and bubbly glacier ice would eSpecially lead to significant results, as related to mechanics of deformation in the icefall and associated wave-band zones. And lastly, more detailed and continuous firn stratigraphy, glaciothermal, and movement studies should be conducted in the region of the Vaughan Lewis névé, to elucidate the control of weather parameters, especially englacial temperature effects, on the volume of ice passing into the lower valley. Such further studies so aimed should result in a fuller understanding of the combined effects of continuous versus discontinuous movements in icefall glaciers. They will also point the way toward a better understanding of the basic role of climatic pulsations and their effects on glaciers. SELECTED REFERENCES Agassiz, Louis, l8h7, Systéme glaciaire ou recherches sur les glaciers, pt. I of Nouvelles etudes et experiences sur les glaciers actuels: Paris, Masson. .Ahlmann, H. N., 19h8, Glaciological research on the North .Atlantic coasts: Royal Geog. Soc., Res. ser. 1, 83 p. Andress, E. C., 1962, NEVE studies on the Juneau Icefield, .Alaska, 1961 with special reference to glacio-hydrology on the Lemon Glacier: Michigan State Univ. (unpublished Master's thesis). ' .Atherton, David, 1963, Comparison of ogive s stems under various regimes: Jour. Glaciology, v. K, no. 35, p- 5&7-557. Beschel, R. E., and Egan, C. P., 1965, Geobotanical investi- gations of a 16th Century moraine on the Bucher Glacier, Juneau Icefield, .Alaska (abs. ): Alaska Sci. Conf., 16th, Juneau. Bostock, H. S., l9h8, Physiography of the Canadian Cordillera with special reference to the area north of the fifty- fizth parallel: Can. Geol. Survey, mem. 2A7, pub. 2h83, 10 p. Buddington, Al F., and Chapin, Theodore, 1929, Geology and mineral deposits of southeastern Alaska: U. S. Geol. Survey Bull. 800, 398 p. .Egan, C. 0., 1965a, Regime trends on the Juneau Icefield névé, .Alaska (abs.): Alaska Sci.~Conf., 16th, Juneau. - ----------- ”1965b, Firn stratigraphy and nEVE'regimt‘trends on the Juneau Icefield, Alaska, 1925-65: Michigan State Univ. (unpublished Master's thesis). Fisher, J. B., 19u2, Forbes' dirt bands on glaciers: New York, privately printed. -- ------------ l9h7, Forbes' and Alaskan dirt bands on glaciers and their origins: Am. Jour. Sci., v. 2&5, “Os 3, ps 137-ILLS. -------------- 1962, Ogives of the Forbes' type on glaciers and a study of their origins: Jour. Glaciology, v. u, no. 31, pa 53-61. 6h 65 Forbes, J. D., 18h2, Third letter on glaciers, addressed to Professor Jameson: Edinburg New. Philos. Jour., Va 32, p. 8“.“91. Freers, T. F., 1965a, Preliminary structural glaciological investigation of wave-bands on the Vaughan Lewis Glacier, Alaska (abs.): Michigan Acad. Sci., Ants and Letters, Ann Arbor. ------------- - 1965b, Significance of structural features of the Vaughan Lewis Glacier, Alaska: N. Dak. Acad. Sci., Proc., v. 19. (in press). Godwin, H., 1949, Pollen analysis of glaciers in special relation to the formation of various types of glacier bands: Jour. Glaciology, v. 1, no. 6, p. 325-329. Havas, T. F., 1965, Surface velocity and strain-rate measure- ments on several Alaskan glaciers, 196a: Michigan State Univ. (unpublished Master's thesis). Hess, H., 190h, Die gletscher: Braunschweig, F., Vieweg. Journal of Glaciology, 1963, Place-name note on the Vaughan Lewis Glacier: v. u, no. 36, p. 666-667. Kamb, Barclay, 196M, Glacier geophysics: Science, v. lh6, no. 36h2. p- 353-365. King, C. Al M., and Lewis, H.‘V., 1961, A tentative theory of ogive formation: Jour. Glaciology, v. 3, no. 29, p0 913 -9390 Kittredge, T. F., 1966, Glaciological and geophysical investigations in 196h and 1965 on arched bands of the Vaughan Lewis Icefall, Juneau Icefield, Alaska: Progress Report, J.I.R.P., Jan. 1966, mimeo. 23 p. Kittredge, T. F., Freers, T. F., and Havas, T., 1965, Structure and deformation study of wave-ogives on the Vaughan Lewis Glacier, Juneau Icefield,.A1aska (abs.): Alaska Sci. Conf., 16th, Juneau. Leighton, F. B., 1951, Ogives of the East Twin Glacier, Alaska-- their nature and origin: Jour. Geology, v. 59, no. 6, p- 578-589. McLane, D., 1960, Results of J.I.R.P. glacier movement surveys in 1960: Pro ress Report, J.I.R.P., Dec. 1960, (m.s.) Found. for GIacier Research. Mlller, M. M., 1952a, Preliminary notes concerning certain glacier structures and glacial lakes on the Juneau Ice- field Research Project, 19h9: J.I.R.P. Report No. 6, Mo Geog. SOC. p. 35-360 66 Miller, M. M., 1952b, The application of electro-thermic boring methods of englacial research: Arctic Inst. North America rept. no. 2, Office of Naval Research Rrojeét 86: .............. 195A: Geological observations: J.I.R.P. Report No. 7, Aml Geog. Soc., p. 79-93. -------------- 1955a, A nomenclature for certain englacial structures: .Acta Geogy, v. 1h, p. 291-299. -------------- 1955b, Glaciothermal studies on the Taku Glacier, southeastern Alaska: pgb. no. 39, de liAssoc. Internat. d'Hydrolo ie, Assemblee Generale de Rome, V. h, p. 309‘3270 -------------- 1956, Glaciology of the Juneau Icefield, South- eastern Alaska: Office of Naval Research Report on Task Order 83001, 2 v. 800 p. -------------- 1958, Phenomena associated with deformation of a glacier bore-hole: Internat. Geod. GeOph s. Union, Assoc. Sci. Hydro., Gen. Assembly, Teronto, 19 7, v.4h, P . 14-37-152 . -------------- 1959, Summary report, geophysical investigation of Project Crater (Classified, U. S. Air Force,.Air Research and DeveIOpment Command), Foundation for Glacier Research, 217 p. - -------------- I963, Taku Glacier evaluation study: State of Alaska, Dept. of Highways, rept., 200 p. -------------- 1966, Preliminary report on field research projects of the Alaskan Glacier Commemorative Program: Rept. to the Committee for Research and EXploration, Nat. Geog. Soc., Foundation for Glacier ReSearch, Seattle. , Miller, M. M., and Prather, B. N., 1965, Teleconnection problems in the glaciation of the Himalaya and of the North Pacific Coast Ranges (abs. ): Alaska Sci. Conf., 16th, Juneau. Nye, J. F., 1952, The mechanics of lacier flow: Jour. Glaciology, v. 2, no. 12, p. 2-93. Quincke, G., 1905, The formation of ice and the grained ' structure of glaciers: Nature, v. 72, p. 5h3-5h5. Russell, 1. C., 1897. Glaciers of North.America: Boston, Ginn Sharp, R. P., 1951, Thermal regimen of firn on upper Seward Glacier, Yukon Territory, Canada: Jour. GlaCIOIOSZ, Vo 1., n0. 9, p. “76-14.87. 67 Sharp, R. P., 1951, Accumulation and ablation on the Seward-Malaspina glacier system, CanadaeAlaska: Geol. Soc. America Bull., v. 62, no. 7, p. 725-7h3. Shreve, R. L., and Kamb, U. B., 1963, Structure of Austerdals Glacier, Norway (abs.): Geol. Soc. America, Ann. Meeting, 76th, Program, p. 150a. Vareschi, V., l9h2, Die pollenanalytische Untersuchung der ‘ Glelscherbewegung, Verbffenthchunger des Geobotanischen: Instituts Rubel in Zurich, no. 19, lh2 p. Washburn, H. B., 1935. Morainic banding of Malaspina and other Alaskan glaciers: Geol. Soc. America Bull., ['10. 14.6, p. 1879-1890. 68 134° 30' I33° 30' 00 .mm .8 .mm P L. D l. T Wu F. T S m N E Y E H E .O l U m \ LR IN: s V 3 III.UI. . m 0 T H 0 '0 A .\ mm WCME 3 S L m C F l A No. 0 S .. m. e m .. . .............u.... . \A’" f r I \ 4.x . Amazmtmorkl . ”J /PI 0 U i x / G ..\..1 n n. a.“ r. —W-\V » .. an \ r...» \s~_/ do: I - 1 o .282 2/ mm rw an x . e i \ \\/.\\,Knl.l elf .. m W \\ .... .. m I ‘0 .... .... In“ 01 .. ... (uh... .o.w M % l ..t....... .L‘r‘ 1 02on 1.--Juneau Icefield, Alaska, with index map Fig. 1112,! ll .lll I181.ll [ll 69 Fig. 2.--0blique aerial photo of the Vaughan Lewis Glacier icefall and wave-bands (Photo by C. P. Egan, 27 Sep- tember 1963). N opaque .9‘/ a los‘“o“\‘¢ . ‘3‘ "A... \‘r. i V. \ \. . ..v\\\ \‘xflt ‘m ow; ‘3! $.\ , ..., \\\: ...... t. .x \ . 8. .d a.\ I‘tiA “New I‘. \i“ \\ t x \\ \\.\.\\\ \\\\\H..) ......V. “x”. . .........eu”...t\v4\\iwfif i \.. .\t\an.H\ ..ss.‘ w . - \:.\,.L. ‘ . in}. ..‘1, ex \7... 71 Fig. 3.--Vertical aerial photo of lower Vaughan Lewis Glacier showing ogives in Sector D and the terminal area Sec- tOr E. Note ice-dammed lake at each of termini (U. S. Navy Photograph, 11 July 1948). FIGURE 4 "Uri“. Elli Bed k roc VAUGHAN LEWIS- GILKEY GLACIER [ J» Debris on ice and medial moraines {6C4 Crevasses and bergschrunds in névé zone _ Crevasses in ice below mean névé-line E Wave-bonds and Forbe's bands(ogives) L'j Névé divide 3?.) .———s Q: Li; Survey point ' Field camp :13“ if; ’" tidy}: a ‘5: ~~’ - I I . ’\\/’.“.'r: i/ Approxrmaie mean neve-line l948-64 r9133; :1 XS": 3 /\i/ 1:5 il,‘ /\// ' :‘ i /\ , ll, \/\i/ \x‘\ s ’\’\/‘7‘/ / \’\/l\‘\/\\‘//K . ‘/—\,\\-\l--l ,\|/ ‘-/\\\\/’,I’/’:\ | ~ ~ \/ \ / ’ ,/\\/\I’\/ ~/\:/‘//’\ \i \\I I\/\\ /\ //|\’\ )’//’\,\i .'/""\ // /\\\\/\ \ I//"/\///, '\ l/ I\//\/\ ,ll/I\\/|\’.\ \ I \\"/\’ \.\/\‘\\\/\//\ ‘lx77/’/I’:I ’, "“ \ H, Gilkey GI. /\"\ i/‘I/ / i’I " 7:".‘y'fx/zxx//,,. _ _ u: v \ "‘v/-/"/./.‘/¢%/.//3 -. . \ l /' _. _ . . ‘ ' J -.".- / I ~ I\ I \ I, \f‘ . l o‘ . . ' I\ .\/l - / \ / " 1W” dice-dammed _ \' /(x \ \ 7 !’/ I /\/‘— 'akes I i I \ \\ _\\’_\ . ‘I . f I . - - , /\\"‘/ ~_ -, TerranSO Gor on Ron e>’—/ ’5‘ -. \ / " . 'xg\’/ \l\’ \//\\g\/\/\/_.:\\Lf 3.1:".- ’\7l\|/ '/ |/\ \ ,_\\ \ \Vaughon LeWIS \’\I.\\’/\’\//\\_\ '///’.- {—IT/ T’\\'/I\/\/' \-—/I\ \/ ’\—/\l/ I 4" \ V~ GlaCIer .' /I \” ///\"/:/ \ l’\\/\,/‘\;Berners /|\/\ \//\’/ [\I\I\\ ’l‘ ‘ \.‘\‘/ I‘\\\\ i/l\' \\ /, ///1/\/ “ I, ,\ \ /'i S \ \ \ ‘\ 3.: \ \T\’/ //\ \,\\\\ ’ ' ‘H ‘_\ \/\/,\i\(-‘ ,-.Ra gel/pox» \/"’-\—" ‘3'-" 7‘ l’xl‘H/ ’ ’ /\\ /\ '\/\\/ \l— \|’\\ \’ ’l Tartarus O O K 73 Figure 4 COMPLEX - \ Mi. Ogilvie R 7780'i237im) aughan Lewis GI. .'~.C-BB raj/V; A] ///j s: /// :0 / Vaughan ; Vaughan Lewis GI. Lewis N évé Range Miles l/2 l 0.8 " l.6 ilomeiers 71L TAKU VAUGHAN LEWIS GLACIER GLACIER kmz mi2 mi2 km2 SOI -2OO TAKU // '- _ LACIER ‘ G \/ __ 439 -I75 ,I " - I — 7.2 - l8.0 - I ~ _ VAUGHAN _ 376 ISO I LENS - / GLACIER " _ I ‘/ ... sis -l25 ,——— — 5.4 — l3.5 _ l — ‘ I 25l -IOO I - _ t: _ / VAUGHAN_ _ / LEwIs 3.6 9.0 I88 - 75 / GLACIER , ‘- — S—YEAR MEAN NEVE— — .. LINE POSITION, — |25 - so 4zoO'IIstmI — ' '7/ I 1 LB '- 4.5 - / TAKU GLACIER MEAN " 53 ‘25 / NEVé-LINE 0F LAST TWO “ - ’ OECAOES, SOOO'ISIOIII) " O - o t 0 —o §e§8§8§95$§z33 s $.88v:_==°58‘66 :oggg§§88oogg <1) 8 ¢ 0 N 8 V 0 N ‘0 0 If «Irv on N) ‘¢ " " “5 "‘° Fig. 5.--Cumulative area curves of the Vaughan Lewis and Taku Glaciers representing total areas below successive 200-foot (60 m) contours. PRIME IACCUMULATION | I I | I OR "SPILLWAY" ICEFALL ZONE 75 IPRIME ABLATION Z ONE 2 LG I 4 O _ // .o.o~.oom..oooo-¢o .omo...ooo=oovo-~o .omo.-ono=oo~o6o I .ono.6t...oooo-oh V//////A.///////////I IN. 8:. 6.56898 a I I I .7 I I [a II II I . 6:._Iooo..ooom-¢m .Omw_-00m:oo¢mlmm Don-ION0300NMIOAL. awn-Iowwsooom lav 83.63.5636,. 86:63:83.: / 836336??? .. .oa~..o-=oo~+6v 83.62.5636» .8: 69:88.3 39.6.6. .88...» 83.68 .oooniun 836:... .oownion .6668 .ooonow I .6862. 568.8 ( 826.2 .oooNIcN nonhIOhw VOO¢NINN .20 I05 VOONNION T .6668 .886. _ .onnI . 68.6. O $3.52. 5...... 0.7 “—0 I lAreo m ZONE I I I S-YEAR MEAN SEASONAL NEVE-I LINE POSITION I I I I I I l i I I l I I I | I I I I km2 3 5 2.8 I 8 0.3 T— Area 4.5 Fig. 6.--Vaughan Lewis Glacier area-elevation histograms showing area between successive 200-foot (60 m) contours. 76 TAKU I VAUGHAN LEWIS GLACIER IGLACIERI GLACIOMORPHIC SECTORS L fi Campl Z 7000 IéZIBOI ~ 000 B30) ~ 000 0520) ~4000 $220) , - 000 Z 9IO) ~2000 (6IO) GLACIOMORPHIC SECTORS bIOOO I I I (300) h \ ) Q- ‘ Z VAUGHAN LEW‘IS"¢ 54 Cam” *- ' GLACIER ,5 <37 \ Sector A-A' Accumulation Zone 2 B Icefall Sector C Wave-band Sector 0 LS D Ogive SecIor kilometers E Terminal Zone Vertical Exaggeraflon 5.3 X Fig. 7.--Glaciomorphic sectors or regime zones of the vaughan Lewis Glacier. Elevation Feel (Meters) 77 w>wc mcwzonm .mpmfiomfio . é \\ 562.52.... \L 9562 am 9:00 .. / 2.303— % \.‘ I: @6560 // €996.33. /mu“V 40 ano .moofim coumomoa cwms no cofipmoofi 6cm mpfiefid 336... swam3m>iaxmh .46. one». go one oflpmsmcumiié .3... . £235 £32 \ / T \ I \ / . 6.. /\ . 2...: . \ . _ ... / my... .3629 3.6... f\\I/Q 22666.3. 0. .6 o o N : .\//.Eooo_..oomn D. . . ._ /: .. Toes-62m / VG, mm 9.30 3.466 \ 1’.. 8.6“:0 ....on . - 22%.”. // \wv/ . m . . . 552; ll OllhfoM/v “ < LO~OOm // \‘ ..-- II// I V? \‘ a / ......... I _ /../ // /. f 26......668 //M\A/ ) .3... . \ 6. 9:8 «0. / Eonuzm \ .5826: 33:6 .6 5.835 All ////I \ /_. faucaom 3.93 623662620 II lb . 0mm0>0L0 “H! 0. :00 a) \ 25 oucoarEEom D x a zo/o.P any E .2; D .. A. To? ) 0.0: onom a ///// ozm sea—comma ..o ano L 5.65 Elam G \ W 32.66.. . / Feet (Meters) 2(O.6) 40.2) 6Il.8) 8(2.4) IOI3.0) I2(3.7I l4(4.2) I6(4.9I I8(5.5) 78 IS September I96l Fiducial Surface New Snow I——-—II——-I Old Snow l I- blatio Surf c III i EXPLANATION' Ice stratum > 0.15103ch I I I — .... :I- "'——= | ‘ Ice column I : ~ Ice lens _____, +4 'Terminology from Miller(l955) I960 Ablation Surface II‘I 20(6.0I south Wall I West Wall Fig. 9.--Stratigraphy of main test pit at Camp BB in late August, 1961. (In c00peration with Andress, 1962) 79 DENSITY (am/cc) 0.350 0.400 0.1150 0.590 (LSLSO 06.00 0.6150 /1 ° 9 September l96l Fiducial Surface '0 _ (3) 20 (6) \ l96| Hand auger core \\ l96l 250-5000c corer in .30 (9) test pit +40 “2) ....50 “5) .60 U8) Fig. lO.--l961 density profiles of upper firn in Vaughan Lewis-Taku glaciomorphic Sector A' (Camp BB). FEET (METERS) IN DEPTH 80 SECTOR A SECTOR A' VAUGHAN LEWIS NEVE TAKU NEVE Ram Resistance Density (amkc) 20 60 I00 I40 ISO .460 500 .540 .580 .620 .660 O I 1 1 I l r r I rfi O l T l I 5; m. U ... UJ E 3 ti 0, U) m m UJ .— 3 uI 6 2 (2) I p P E In 9 in u) (3) 3 I2 (4) I ,_ IS a_ (5) IL) 0 l8 (6) Fig. ll.--Density profile in 1963 firn, Site BB (Taku Glacier) and rammésonde profile, Sector.A (Vaughan Lewis Glacier). 81 I3 SEPTEMBER I96I FIDUCIAL SURFACE I96| A. S. NOTATIONS I0(3) I7'6" (5.3m) I950 A.S. 20(6) 4'5" 8 I958 A.S. . .. .. I cm I.S.,D.l_, E . u 5 (I3cm)I.S. )- — — — — — — ‘ —5"(I3cm)l.s.(Im.I h.) 30(9) '957 A5. (I.6m) z _ V 6 I- I956 A.S. ("8”“) In 4, If 40"2’ I955 A.s. (|.?.m) .. — — — - — -5l6u(l 7—‘4 (IochI-S-(InI-I . In . 5 I937. ATS-T "" — — — . I.$..(I‘I'II.I 50([5’ — — — — — _ _ — —2”(5cm)|.S.(int) 1 I953 A.S. (I.8.MI V.V.D.L. ... a I“ O 6008) I952 A.S. (Leum) V.D.L. 6'6 I A. . .0 '95 s (2 .m) V.D.L. 8 70(2l) I950 A.5.(?I (2.4m) I.S.(inl.) -'- ICE STRATUM (INTERMITTENTI IS. = ICE STRATUM D.L. ‘-' DIRTY LAYER V.D.L. = VERY DIRTY LAYER V.V.D.L. = VERY VERY DIRTY LAYER AS. = ANNUAL ABLATION SURFACE STRATIGRAPHIC TERMINOLOGY FROM MILLER (I955) Fig. 12.--Stratigraphy of crevasse wall, upper Taku Glacier, Site 8D, elev. 5700 feet (1750 111), September, 1961. (After Andress, 1962) I0(3) 20(6) 30(9) IN FEET (METERS) 40(I2) DEPTH s TRATI GRAPHY CAMP eA elev. sssp'IIaIOmI Fiducial Surface 82 FIRN THICKNESS CAMPIOB elev. 3650'“ I I5m) FiducIaI Surface 8 September I96I I9 August l96l WW /W\M~\MM4 IZZZZLL'_—---—- 9// ..-____--_.. 0V / WW I— ————————————— 9Q) / / \ / ‘9' / ............. q? _____________ . e" / / / _______________ ‘0' Q)? 0) a, /‘ _________________/ == Ice strata < I"(2.5cm) thick = Ice strata > I"(2.5cm) thick A.S. Annual ablation surface Fig. 13.--Stratigraphy at Site 8A and firn thickness at Site 103 measured from hand auger cores. (After Andress, 1962) 83 DENSITY (gm/cc) METERSO .200 .400 .600 800 FEET I I ) I 0 27-28 July I962 FiducialSurface | —I0 DENSITY PROFILE FROM HAND AUGER SAMPLES SITE 8A, 27 JULY l962 DENSITY PROFILE FROM HAND AUGER SAMPLES SITE 88, 28 JULY I962 Fig. luv-Density profile, Sector A', Sites 8A and BB, upper Taku Glacier néve. MAIN DRILL ‘ \ ale—SWIScha‘ GALVANIZED PIPE E 2 2! :0 I0 MACHINED BRASS TIP 1 ___ I L L75" (44cm) Fig. lS.--Electr0thermal glacier drill, ZOOO-watt element; lZO-volt wiring detail as used at Site 8A, upper Taku Glacier, elev. 5900 feet (1800 m),.August-September, 1961. (After.Andress, 1962) 8S .Hooa peasauaam : 60 amsma< om .dw Spam um 05"» cowamuaacoaimoIcuaaa 6cm mampiauon canon amenonpopuoaamII.o~ .mwm manor 2. m2; ozEOm 4435.04 0~_ 0: 00. 00 00 0h 00 on 0... 0m 0w 0. 0 4 dI .— d u 4 J A d d + 4 _ _ _ mxkdmo mmmrk ...4 m..0: z. .3309 uNomu maom zofizudmam z. kozximi .330! M. _d _ .8300 W. £0303 I . 896.. N .92: 65.66 .26. SE: 66:38:66 06 5866 8.6% 3 ... .8066. n. IIIMIIJI .2066 M - W 2:68 _ W 3900 3 3.2.66 66.: 62268653 _ f :80» M... 6.6. 6.9.3 662666 6:... I/ 8.000 .w w .28 _ 2866 6:82.» .6 .56.. .2. 26.35:. 5 26.6.8 :3\ _ .mcoe . Saw . 8.6» _I III L . AoVON ooatam I I I I I c2334 000. J. 43.0. 3256 6.63.... .66. .334 mm)! IIIIII $686.. agmflwam 862.? Stan 28.8 $.06. 6 .36: 5... 23.66.62. 2. 3.2.38 4425:7656me 86 -O.9 -O.7 -O.5 -O.3 -O.| 0°C 0 A 1 L ‘ 1 ‘ ‘ ' 1 I 4 September l96I I Fiducial Surface IO(3)- : _. .1... I960 Ablotlon Surface 20(6) I- I L I Extrapolated effective ;. _ _ | depth of penetration of 50(9) _ _ _ _“ _|— I960-6I cold wave as | of 4 September l96l 4002) - I I - 5005) I I m I “ some) » I u: ._ l 70(2l) r I m I z I - 30(24) I I | I ’- 90(27) " I “’ l u: IOO(30) - I | u I “cum » I z | I20(36) ~ K.E-— I |30(39) - | : K.E- I a I K.E-Depth at which |4o(42) _ | knot in suspension “’ I rope was frozen 0 in hole 150(45I ~ : I60(48’ I l I T v r I _l r J -O.9 -O.7 -O.5 - O .3 -O.I 0°C Fig. l7.--Englac1al temperature profile in electro- thermal bore hole at Site 8A, Sector A', as of I; September 1961. 1. not?» 3.5.35.5; .. r Ln 87 Fig. 18.—-Recumbent isoclinal fold in bubbly glacier ice, north side of glacier, near base of Vaughan Lewis icefall (Photo by T. F. Freers, 9 September 1961). Figure 18 89 Fig. l9.--Surface expression of white-ice layers on crest of wave—band in Sector C. View looking across glacier toward south (Photo by T. F. Freers,lO September 1961). fl, 1 ’ A . ‘l-{yfly ‘w.’ _- r‘ I g \f’ '_'. .1 'V. - x -: ...l ‘ n. 0‘ H ” h '5 00 a... (1.. 91 TOP OF ICEFALL ///:/=—4——\\\ .. MM Rodiol crevasses f... .. a .... ”"5“?“ "“0559 H I G H L Y .23232'2233323'233'2232': Bed’oc" — White—ice F-z ' Ice told L E] Wave-bond S E R A C C E D \ 232325=E=E:E:;:;;;;;zgs§3izézisisiz A N D , — -- s:22222222323223:ésisiséséséézésis. ,/’ “‘ * rifles; CREVASSED gfifig ififififii? ZONE zfiiflififi 4soo'usvsm) -_ iii???5f‘if;f;2;§;:§§§§§§§§§§§§‘giii; 0000 ‘~‘ ,\ - zisis$3253;313:???35532325252323:is :;;;;;sisisisizis§2§3§2§2§2§2§s§2§3§3§2§:, V , F-I .iiiiii:3§§§§§§§§§§§§§§§§§§E§i§§§33523232335E oaoo F-a I I 0' eaaagfigfinqui>> «IE5... Anninr- gnaggggg .............................. ooooooooooooooooooooooooooooo oooooooooooooooooooooooooooooo oooooooooooooooooooooooo ......................... uuuuuuuuuuuuuuuuuuuuuuuu ......................... ------------------------ ......................... --------------------------- ........................... .......................... .......................... ......................... ooooooooooooooooooooooooo 66666666666 ........... cccccccccccc ............... nnnnnnnnnnnnnnn ---------- ........ ' A a/’///,/ F- “It“ ‘ 4000'I225m)-—-~ -- 7% OF ICEFALL \ ' , - ‘6 / WW, “SE Fig. 20.--Schematic representation'of the Va u ban Lewi icefall, Sector B, showing relationship of main stguctural s features between 000 and 000 f elevation. LI- 5 eet “225 and 1675 m) r) BEDROCK E WAVE- BANDS N MEDIAL MORAINE 65§ Névé Camp l8 (Sector A) lcetaH (Sector 8) Individual bands numbered for purposes of discussion in text Miles 0 Q5 g I fl 0 0.8 Kilometers Fig. 21.--Area of wave-bands, Sector C, on the Vaughan Lewis Glacier. 93 .Amood .6on8ouaomv uoaowflo maze; cmcmsm> any mo oaflmaoacoo may mcoam.m o» a mocmmuo>mz no ogqhona commune HmcofluoomimmoaUai.NN .mfim x6 26.25633 63:3; .6553 Emu BEVOOON 80.0009 803000. Aomzoom 23:32. mom: __ .65 2.6.6 8.2.." .5222... .mm.\ 5200.0 AIII 0’00 0 oz<3 voz<>> m02<3 N oz<3 50>00|30cw 20.36.... _ 024m Im>< 3 . a: 0m '89 oo. (883.13") 133.4 III .II {If i .Amoofi quanEauaomV ”H63 omwm>o66 a mcoflm 660166653 uopaflfiouicoc 6:6 cofiumfiflou 6663656 N 6cmmio>m3in.mm .66m .6. / / / .16. 872...; \ / 8. 3.2.8-8.. 2...; \ 36.) 66.6.. .4 62.2.3 06 6.0 \ . N 6666.363 06 :62 £3: 06 223.6 626566.665 5.656 II' 1 < 2366 ..u. / 9 I x . .3 . / one xom 26.2566qu .. mmwkmz on m _ O .. T « IJ. /m~. 00— on 0 .E .66\ hum... cozoem 669.0 95 .Ammma .aonamaaom. ”an: ommm>ouo a anode ooflnouflc3 6u66m~60icoc 6:6 aouumfigou 6663656 : 666mi6>63in.:m .mam xm 20.k mmMFmZ 0m m__ Io nXu_ hum mu mem «mm L: aNm\ own .66 06» com cozoom 666.0 mm_0<40 AIIIIIIII 2300 8. 622.678: 223 \ cozoEx 06 az.‘\\ e26.8.-223 \\ 32> can. c 6666.363 *6 :6; £666 *6 :23..." 6.3652620 96 Fig. 25.--Photo of smooth relatively unbroken white- ice cores and rough broken bubbly glacier ice cores. Cores taken within a yard (meter) of each other in Sector C. (Photo by T. F. Freers, 10 September 1961). mm shaman 98 63630 336..— 665666> 6:6 .66 66666 6666n6>63 666 “.6666“ 6:6 66 66686>os 6:6 moaafloo~6> 6066666 goofini.om .mam 9.6.6.665. m. 6240 2 6.0 No 0 66.6 66.6 6 . 2.... 66:2 .. _ 660m ». wozeFmE .. . . .. C 6-“. . . ..II s ‘ ‘I‘I )6 i o n... Y\w+ .\ xx . \ . mlafi OVA/A7 \\\\ AVA? A)o \ 6... Au \65 mi \ \Tn .va kcx ...“... 07“. k .06. 86.66.63,. 0. 666 m \\ 6.6.; :6 69.6. 2665266662 \ huu\ & .... .63; 5.66.6> ) £3 3.6.6 26526.... 6.... m/q7xw \ .26; 3.66.; x ......... 5.... 6.66656 66. ..a\ >60 3.. 8222 6-6 0430 6.6. 66 6 6... / q fl M H u H a $0 66 66 6 e6 mmadjo >60 can. .66.... 0924223 x >.—._00...m> 99 £36660 66364 666663, of .66 6666 vcmnnu>63 6:6 :6 mpcmso>oa 6:6 mmmufioo~6> .moo~ 6» goo~ .666hnozhnn.wm .mmm 22666:: m. 6266B 6.6[ 6.6 6 2 66.6 66.6 6 . 8: .86 I 66:2 .. . > 66265.6 \L< ’ . Q!!! 0 .... )U. . q, .4 .. 3 . . 94 J: ...n. . .w 4/0 ...x. .. RH. \\ $4 ,.\6 A)& .. A1.\\|L. \ x &/0 xx R IV \. u x ‘\\\\\b 6.. .262, »._66_6> \ \W) 622666 $1.7 666. $525 .6 .65... x - .. )0 665666 .. . Ob .. . . . r - .66. 3622666 6 .265 o L. / - - ,- I .. 4vxw >60 .66 26.6: ... 6.6 6.6 6 \.6 n u H L A— . O.N 0.. O >._._U.OJM> 100 .6666660 66364 666666>.666 no 6666 6666u6>63 666 66 666666 666666 666 666656>os .666666666> :oo~uu.mm .666 .. ..w z .... .6. >60 .66 6.262 ... ..w 6.6 6.6 6 ... ..... 0A 7 F . J .. .6 o N — o m o. . I... 4‘ >60 .60 .666. ...x ......a..... ¢ CBS? 0 ... ....n \// .36. . 6+ 4. .. . > x . ) 666. £35236 ...»: W\ \w 666 666664 c. 6>66 Nu >0 ......n m @/47 66.56 6665 266663666! Auk \\ \ 9 0.: 0 & ...... 4 .. q . . .. .6662 666.3% X 3... 4 ... .3. ., ... .. .66... N ,. . 66.66., >:6o_6> \\ 6.. ... . «U 0 m\ Ob) ¢¢ )0 6 / AMA 226.66.. x [WW/GA 6.. $9 Oxv v.0 N .o o .... 666 66. .6 6 ,1 «0:2 \v 66236.6 65... 6660 6 101 x l6000 6F8 ’ P (4880) / |4poo 604' r (4270) l2,000 (3660) l0,000 (3050) How D'wec‘mn ‘ 8000 (2440) FEET (METERS) IN 6000 ([830) I960 PROFILE (Surveyed 2| and 30 July) DISTANCE ,l96l PROFILE l" (.2500, 1’ (Surveyed l9 August and 5 September) I —_ —_ .6 ___.6 2000 -r (GKD I Comp 8 Survey 2(O.6) “0.3) 0.5(OJ5) 0 Point VELOCITY IN FEET(METERS) PER DAY Fig. 29.--1960 and 1961 surface movement. along Profile VIII on the North Branch, Taku Glacier in the Carnp 8 Sector. 102 Surveyed on I? August and l2 September I96I - I2,000 (3660) . l0,000 (3050) < 8000 F‘°“' (2440) DiyeCTIon FEET (METERS) . 6000 (I830) . 4000 0220) DISTANCE 4 2000 (6IO) , j L 1 A Camp 9 2(05) No.3) 0 Survey point ' VELOCITY m FEET(METERS) PER DAY Y Fig. 30.--1961 surface movement along Profile V11 on the North Branch, Taku Glacier in the Camp 9 Sector. 103 X 060'I2 l _I4pOO (4270) 604I ‘/96P9 6040 ,, //// .lZpOO /// (3660) I960 PROFILE (Surveyed 60-9 / / 20 July and 6 August) 06l-8 / l96l PROFILE (Surveyed 4 [0,000 / / 25 July and I2 (3050) . 60-8 ( September f‘l96l - a) 60-7 . 8000 33 J ‘ (2440)::I 6I-6 5 Flow 60’6 “\ ‘— ... Direciion \ .6000 6 60-5 . \ (I330) t2 /|960 Site of crevasse stratigraphy 6l-3 \\ ‘ 60-4 I discussed in max I \ 44000 5 \ I (I220) \ . 60-3 ~\\ . \\\ |u \ 60-2 0 '\\ z \ ‘ .2000 : 60-l . (GIO) (2 SH ° O I I ComplO Y J g ikSul’VOy 2(O.6) “0.3) Point VELOCITY IN FEET (METERS) PER DAY (Sto.l9) Fig. 3l--l960 and 1961 surface movement along Profile IV on the Main Branch, Taku Glacier in the Camp 10 Sector. 101; .Am3mfi> flmcowuoomummOnov uofiomfio mwzoq cmcmsm> on» cw uo%m~ oofinopmcz a mo acoan~m>oo 020 cm muco>o Mo oocosvom flmofiuocpoazmau.mm .wfim \oo.-o::3/ .33. 02-223 \ 50>Oo 30cm Eofico: 989.033 30:». L2c_3\ 30:06 was .960 30cm .23 22.2 23.303 0 Lo 22.32260 00_IO:£3 UGO UCODIO>O3|¢ lug—Um UCO CO_MWOLQEOU LQ£~LDK I awn—um 02-223 2c. «23 co. c3325 30:... .82.: .0 5.303500 IN Qme. 30:» .25) *0 05.5... 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H...H.H...H.H.Hfiuu. _ awhw 106 .00.000.00 000.000.00 .00.000.00 000.0.0.0. 0.0.00..0. 0.0.000.0 000.00..0 000.000.0 .00..00.0 .00.000.. 000.0.... 00...00.. 000.000.. 000.000.. 00...00.0 000.0.0.0 0...000.0 000.000.0 000.000.0 .00..00.0 000.0...0 0.0..00.0 .00.000.0 000...0.0 000008 mumsum .0...00..00 000.0.0.000 .0...00.0.0 .0....0.00. 000.00..00. 00..000.00. 00..000.00 000.000.00 0.0.000.00 000..00.00 .00.000.00 000.000.00 .00..00.00 000.000..0 000.000... 000.000.00 000.000.00 0.0.000.00 000.000.00 000.00..00 000.0.0.00 000.000.00 000..00..0 00..000.00 0000 mumsum HNEQUGH “SCH—$.00 0000 summaom 000< 0>Humaaaao 0H.H mm.H Nm.H do.m NH.m Hm.o a0.o 0m.o 0H.o comm .... 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Q .... mmH zo mZON W>mz mmmmb Mme OH szHZMMH mmH 20mm mmDOHzoo Aa_oov HOOhuoom m>HmmMUUDm zmm3Hmm O\P‘€>U1BDK>O\U1C>€)¥‘$‘P‘UJW>$‘3‘WD3‘P‘GDNDWDBJBJBJ\JP‘U1¢>$‘GDBJ\JWDQDC>O\h‘\lP*¢>U)¥‘ Date 8/31/61 9/1/61 Time 1515 1545 1615 1645 1715 1745 1815 1845 1915 1945 2015 2045 2115 2145 2215 2245 2315 2345 0015 0045 0115 0145 0215 0245 0315 0345 0415 0445 0515 0545 0615 0645 0715 0745 0815 0845 0915 0945 1015 1045 1115 1145 1215 1245 1315 1345 1415 1445 1515 1545 Advance In. Cm 04 10 04 10 04 10 06 15 03 08 04 10 04 10 06 15 04 10 03 08 03 08 03 08 03 08 03 08 03 08 02 05 0 0 0 0 03 08 03 08 01 03 01 03 03 08 06 15 02 05 03 08 02 05 06 15 03 08 02 05 05 13 04 10 04 10 O4 10 01 03 03 08 04 10 01 03 02 05 04 10 04 10 02 05 02 05 02 05 05 13 03 08 03 08 04 10 03 08 01 03 Ft. 112. 112. 113. 113. 113. 114. 114. 115. 115. 115. 115. 116. 116. 116. 116. 117. 117. 117. 117. 117. 117. 117. 117. 118. 118. 118. 119. 119. 119. 119. 120. 120. 121. 121. 121. 121. 122. 122. 122. 122. 122. 123. 123. 123. 123. 124. 124. 124. 124. 125. ML; Depth OONDHODWHQOWHONb-PONJ-‘KOCDUOKDC‘bOVO‘UWOOOQC‘bHOO-POMN\OO\l—‘CDJ-\ 34. 34. 34. 34. 34. 34. 34. 35. 35. 35. 35. 35. 35. 35. 35. 35. 35. 35. 35. 35. 35. 35. 36. 36. 36. 36. 36. 36. 36. 36. 36. 36. 36. 37. 37. 37. 37. 37. 37. 37. 37. 37. 37. 37. 37. 37. 37. 38. 38. 38. Meters BJFJI>G>\JO\UIDWJ Remarks VVO‘U‘PWW Generator left running for total advance of one foot eight inches. I—‘HOOOGJO‘O‘KDUI-L‘wNNHooomNO‘UTUIwWNl-‘OOOCDCDNN Generator not running during this period. Date 9/1/61 9/2/61 Time 1615 1645 1715 1745 1815 1845 1915 1945 2015 2045 2115 2145 72215 2245 2315 2345 0015 0045 0115 0145 0215 0245 0315 0345 0415 0445 0515 0545 0615 0645 0715 0745 0815 0845 0915 0945 1015 1045 1115 1145 1215 1245 1315 1345 1415 1445 1515 1545 1615 1645 Advance In. Cm 04 10 03 08 04 10 02 05 02 05 04 10 05 13 04 10 05 13 04 10 04 10 04 10 0 0 0 0 0 0 0 0 03 08 03 08 02 05 02 05 02 05 03 08 03 08 02 05 O3 08 04 10 02 05 O6 15 0 0 02 05 03 08 02 05 02 05 02 05 02 05 04 10 02 05 05 13 02 05 04 10 0 0 03 08 06 15 03 08 02 05 02 05 01 03 02 05 02 05 02 05 115 Depth Remarks Ft. Meters 125.4 38.2 125.6 38.3 125.9 38.4 126.1 38.5 126.3 38.5 126.6 38.6 127.0 38.7 127.4 38.9 Generator left running for 127.8 39.0 total advance of two feet 128.1 39.1 six inches. 128.4 39.2 128.8 39.3 128.8 39.3 128.8 39.3 Generator not running 128.8 39.3 during this period 128.8 39.3 129.0 39.3 129.3 39.4 129.4 39.5 129.6 39.5 129.8 39.6 130.0 39.7 130.3 39.7 130.4 39.8 130.7 39.9 131.0 40.0 131.2 40.0 131.7 40.2 131.7 40.2 131.9 40.2 132.1 40.3 132.3 40.4 132.4 40.4 132.6 40.4 132.8 40.5 133.1 40.6 133.3 40.7 133.7 40.8 133.9 40.8 134.2 40.9 134.2 40.9 134.4 41.0 134.9 41.1 135.2 41.2 135.4 41.3 135.5 41.3 135.6 41.4 135.8 41.4 135.9 41.5 5 136.1 41. Date 9/2/61 9/3/61 9/4/61 Time 1715 1745 1815 1845 1915 1945 2015 2045 2115 2145 2215 2245 2315 2345 0015 0745 0815 0845 0915 0945 1015 1115 1145 1215 1245 1315 1345 1415 1445 1515 1545 1615 1645 1715 1745 1815 1845 1915 1945 .2015 2045 2115 2145 2215 2245 2315 2345 0015 0045 Advance In. Cm 02 05 04 10 03 08 03 08 03 08 03 08 05 13 05 13 05 13 05 13 05 13 05 13 05 13 0 0 0 0 0 0 06 15 04 10 02 05 02 05 02 05 02 05 02 05 02 05 03 08 03 08 01 03 04 10 06 15 05 13 04 10 02 05 05 13 04 10 01 03 01 03 02 05 02 05 03 08 02 05 03 08 02 05 02 05 0 0 0 0 0 0 O4 10 02 05 02 05 116 32923159. Generator left running for total advance of two feet eleven inches. Generator not running. No advance, rope frozen in hole. Leer-E Ft Meters 136.3 41.6 136.6 41.7 136.9 41.8 137.1 41.8 137.4 41.9 137.6 42.0 138.0 42.1 138.4 42.2 138.9 42.4 139.3 42.5 139.7 42.6 140.1 42.7 140.5 42.9 140.5 42.9 140.5 42.9 140.5 42.9 141.0 43.0 141.4 43.1 141 5 43.2 141.7 43.2 141.9 43.3 142.2 43.4 142.4 43.4 142.5 43.5 142.8 43.6 143.0 43.6 143.1 43.6 143.4 43.7 143.9 43.9 144.4 44.0 144.7 44.1 144.9 44.2 145.3 44.3 145.6 44.4 145.7 44.4 145.8 44.5 145.9 44.5 146.1 44.6 146.4 44.7 146.5 44.7 146.8 44.8 146.9 44.8 147.1 44.9 147.1 44.9 147.1 44.9 147.1 44.9 147.4 45.0 147.6 45.0 Generator left running for total advance of one foot four inches. Generator not running during this period. Date 9/4/61 Time 0115 0145 0215 0245 0315 0345 0415 0445 0515 0545 0615 0645 0715 0745 0815 0845 0915 0945 1015 1045 1115 Advance In. Cm 03 08 04 10 04 10 04 10 01. 03 01 03 0 0 02 05 02 05 02 05 02 05 02 05 02 05 02 05 01 03 02 05 01 03 02 05 02 05 02 05 Depth Ft Meters 148.0 45.1 148.4 45.3 148.7 .45.4 149.0 45.4 149.1 45.5 149.2 45.5 149.2 45.5 149.4 45.6 149.5 45.6 149.7 45.7 149.9 45.7 150.0 45.8 150.2 45.8 150.4 45.9 150.4 45.9 150.6 45.9 150.7 46.0 .9 .0 .0 .1 .2 1 117 Remarks Rope frozen in hole; drilling completed. 118 .0.0: upon m0 008* k. w. .0 0H m. 0H m. N. H. OH HNm0-tnxowooox 00.0- 0000 00.0 - 0000 .0.0- 0000 00.0 - 0000 00.0- .000 0..0- 0000 ..00 00.0- 0.00 00.0 - 0.00 00.0- 0.00 00.0 - 0.00 .0.0- .000 0..0- 0000 0.00 00.0- 0000 .0.0 - 0.00 ...0- 0000 00.0 - 0000 00.0- .000 0..0- .000 0.00 00.0- 0000 00.0 - 0000 .0.0- 0000 00.0 - 0000 .0.0- 0.00 0..0- 0000 0.00 00.0- .000 00.0 - 0000 00 0- 0000 00.0 - 0000 00.0- 0000 0..0- 0.00 0.00 00.0- 0.00 00.0 - 0.00 00.0- 0.00 00.0 - 0.00 00.0- 0.00 0..0- .000 0.00 00.0- 0000 00.0 - 0000 00.0- .000 00.0 - 0000 00.0- 0000 .. 0- 0000 ..00 00.0- 0.00 00.0 - 0.00 ...0- 0.00 00.0 - 0.00 00.0- 0000 0..0- .000 0.00 00.0- 0000 00.0 - 0000 00.0- 0000 00.0 - .000 00.0- 0000 00.0- .000 0000 00.0- 0.00 .0.0 - 0.00 0..0- .000 00.0 - 0.00 .0.0- ..00 00.0- 0000 0000 0..0- 0000 0..0 - .000 0..0- 0.00 0..0 - 0.00 00.0- 0.00 0..0- ..00 .000 00.0- 0000 00.0 - 0000 00.0- 0.00 00.0 - 0.00 00..- 0000 00..- 0000 0000 00..- 0000 00.. - 0000 00..- 0000 00.. - 0000 00.0- 0000 ...0- 0..0 0000 00.0- 0000 00.0 - .000 ....- 0000 00.. - 0000 .0..- 0000 0..0- 0000 0000 00.0- 0.00 00.0 - ..00 0..0- 0000 00.0 - .000 00..- 0000 .0..- .000 0000 00.0- 0000 00.0 - 0000 ...0- .0.0 00.. - .000 .0..- 00.0 .0..- 0000 0000 ..00- 00.0 00.0 + 00.0 00..- 0000 .0.. - 0000 00.0- 0.00 00.0- .000 .000 00.0+ 0000 00.0.+ .0.. .0 0- 0000 00.0.+ 0.0. 00.0- 0.00 0..0+ 0000 0000 m .0 .H .m .H .m .H .m .H .m .H .m .02 .Euona .000 000. .000 000. .00: 000. .000 0000 .0.0 000. .0.0 000. 0:.0 .0\0\0 .0\0\0 .0\0.0 0000 Esoum cone 000 0.000 .3 0.0.0 .00. 0000 .>0.0 MACE-mmom A8 00v Boom-”ma n mHZMZHMDmh~a>0\sz 00.0 - 0000 00.0 0000 ..00 00.0 - 0.00 00.0 0.00 0.00 ...0 - 0000 0..0 0000 0.00 00.0 - 0000 00.0 .000 0.00 00.0 - 0000 00.0 0000 0.00 00.0 - 0.00 00.0 ..00 0.00 00.0 - 0000 .0.0 0000 ..00 00.0 - 0.00 00.0 0.00 0.00 00.0 - 0000 00.0 0000 0000 .0.0 - 0.00 00.0 0.00 0000 0..0 - .000 0..0 0000 .000 00.0 - 0.00 00.0 ..00 0000 0..0 - .000 0..0 0000 0000 ...0 - .000 ...0 0000 0000 00.0 - 0000 00.0 0000 0000 00.0 - 0000 00.0 0000 0000 00.0 + .000 0..0 .000 .000 00.0.+ .00. 0....+ 000. 0000 .H .m .H .m .02 .EHmSH .0.0 00.. .00: 000. 02.0 .0.0..0 .0.0..0 00<0 121 .000: 0000 no 009% 0..0 0.0.0 000.0 000.0 ...0 .00.0 ..0.0 000.0 00.0 - 00.0 00.0- 00.0 00.0 - 00.0 00.0- 00.0 00.0- 0000 0000 0. 00.0 - 0.00 00.0- 0.00 00.0 - ..00 00.0- 0.00 .0.0- .000 0000 0. 00.0 - 0000 0..0- 0000 0..0 - 0000 0..0- .000 00.0- 0000 0000 0. 00.0 - 0000 00.0- 0000 .... + 0000 00.0- 0000 00.0+ 0000 0000 0. ...0.+ 000. 00 ..+ 000. .0.0- .000 00.0- 0000 .000 ... 0..0.+ 000. 0000 0. 00.0 + 0000 0000 0 .H .m .m .m .H .m _H .m .H .0 .oz . EHwSH. .0.0 00.. .000 000. .00: 0000 .00: 000. .00: 000. 02.0 .0.0000 .0\0\0 .00000 .0.0.0 ma<0 mBSOflM 0 "0 000 0.000 .a 0.0.0 0000 0000 .>o.m O mqomummom A8 may Hoomnoo n mfizmzmm3m00\0m 200\2_%00\0m 000\2.%00\0m 000002. 0000 000002. 0000. 000002. 0000 0000 02000 0008 0.00-0 0.x<-m, 0.000m, 0.x<-0. 0.x<-0_ 0.00-0T1, -0>oz m0.0.00.0> 00000000000 00.0.mom .moa. 000w0< .m 000 .00. 003800000 0. 000 m 00 00m0>0am 000M 00mm-0>03 - . 00mm mom. OH .00. Qz< .00. .mmHo mmfi mo Hzm22>02_mu08 oz 0:00 0000000 - m 0000 -- - -- -- -- -- -- -- 00.000 0..0000 00.000 00.0000 m0\0m\0 «0.0 0..0 .0.0 00.0 00.0 00.0 00.000- 00.0N0- 00.000 ~0.00m 00.000 00.0000 00\00\0 00-0 -- -- -- -- -- -- .0.000- 00.000- 0..000 00..00 N0.~00 00.0000 00\0\0 -- - 00.0 00.0 00.0 00.0 -- -- 0~.000 00.0000 ...000 0~.00.0 00\0nw0 00.0 0..0 00.0 .0.N 00.0 00.0 .0.000- 00.000- N0..0 NN..00 .0.0N0 00.00.0 00\00\0 00-m -- -- -- -- -- -- 00.000- 00.000- 00.00 mm.~00 00..00 00.0000 00\0\0 .0z 000\2 000\0m 000\2.000\0m 000\2 000\0m 000002 0000 000002. 0000 000002. 0000 0000 00000 0008 0000-0 00x<-0 00x<-x 00x<-N 0004-0 0000-0 -0>o= 000000000> 00wm0000000 00000000 125 APPENDIX I SURFACE MOVEMENT AND STRESS TENSOR IN THE WAVE-BAND ZONE OF THE VAUGHAN LEWIS GLACIER, 1964 1964 movement measurements (Havas, 1965) surveyed 22 days in August and September 1964. Y-Movement X~Movement Movement Stake No. Feet Per Day .Meters Per Day Feet Per Day Meters Per Day 4 1.38 0.42 0.36 0.11 5 1.15 0.35 0.36 0.11 6 1.15 0.35 0.30 0.09 7 1.28 0.39 0.13 0.04 8 1.38 0.42 0.07 0.02 126 APPENDIX J SURFACE MOVEMENT MEASUREMENTS ALONG PROFILE VIII, NORTH BRANCH TAKU GLACIER IN THE CAMP 8 SECTOR Part 1 - 1960 Measurements (after D. McLane, J.I.R.P., 1960) Surveyed on 21 July and 30 July 1960 Position Coordinates Velocity X-Axis Y-Axis Y-Axis Movement Stake No. Feet Meters Feet Meters Ft/Day M/Day 1 5514.00 1680 0 0 5514.00 1680 2.57 0.8 0.26 0.08 2 6197.00 1889 0 0 6197.00 1889 4.75 1.5 0.48 0.15 3 6295.00 1919 0 0 6295.00 1919 2.64 0.8 0.26 0.08 4 7035.00 2144 0 0 7035.00 2144 4.81 1.5 0.48 0.15 5 7665.00 2336 0 0 7665.00 2336 5.29 1.6 0.53 0.16 6 8402.00 2561 0 0 8402.00 2561 7.63 2.3 0.76 0.23 7 9250.00 2819 0 0 9250.00 2819 8.52 2.6 0.85 0.26 8 10225.00 3117 0 0 10225.00 3117 7.61 2.3 0.76 0.23 9 10871.00 3313 0 0 10871.00 3313 9.09 2.8 0.91 0.28 10 11730.00 3575 0 0 11730.00 3575 7.96 2.4 0.80 0.24 11 13490.00 4112 0 0 13490.00 4112 7.26 2.2 0.73 0.22 127 Part 2 - 1961 Measurements Surveyed on 19 August and 5 September 1961 Position Coordinates Velocity X-Axis Y-Axis Y-Axis Movement Stake No. Feet Meters Feet Meters Ft/Day M/Day 1 5959.15 1816 0 0 5959.15 1816 7.12 2.2 0.40 0.12 2 7177.73 2188 0 0 7177.73 2188 7.68 2.3 0.43 0.13 3 8347.08 2544 0 0 8347.08 2544 9.06 2.8 0.50 0.15 4 9626.98 2934 0 0 9626.98 2934 8.89 2.7 0.49 0.15 5 11035.86 3364 0 0 11035.86 3364 7.19 2.2 0.40 0.12 6 12654.08 3857 .0 0 12654.08 3857 6.63 2.0 0.37 0.11 7 14298.97 4358 0 0 14298.97 4358 4.20 1.3 0.23 0.07 8 15866.38 4836 0 0 15866.38 4836 2.17 0.7 0.12 0.04 128 APPENDIX K SURFACE MOVEMENT MEASUREMENTS ALONG PROFILE VII, NORTH BRANCH Surveyed on 17 August and 12 September 1961. TAKU GLACIER IN THE CAMP 9 SECTOR, 1961 Position Coordinates Velocity X-Axis Y-Axis Y-Axis Movement Stake No. Feet Meters Feet Meters Ft/Day MjDay 1 3249.83 990 0 0 3249.83 990 3.77 1.15 0.15 0.05 2 4151.49 1265 0 0 4151.49 1265 9.15 2.79 0.34 0.10 4 6073.25 1851 0 0 6073.25 1851 26.31 8.02 0.98 0.30 5 7422.45 2262 0 0 7422.45 2262 28.61 8.72 1.06 0.32 6 8522.99 #2598 0 0 8522.99 -2598 30.68 9.35 1.14 0.35 7 10409.26 3173 0 0 10409.26 3173 29.82 9.09 1.10 0.34 8 12055.04 3674 0 0 12055.04 3674 6.04 0.73 0.22 129 o~.o oo.o : : m¢m¢ o.NoN¢H o 0 NH om.o mH.H u a snow m.¢¢NMH o o u s mmoq ¢.om~mH o 0 HH ¢m.o mm.H : 3 «non m.ooouH o o u I Noon ¢.mHoNH o 0 0H Hw.o mo.~ : u mama w.wm¢m o o u u «emu «.munm o o w mo.c mo.m n 1 menu «.muum o o a u NHmN N.o¢Nw o c m No.o No.m n a ONHN m.¢nmo o o u u wNHN n.um¢o o o o om.o mw.H u u HoNH n.wnnm o o u 1 NouH «.mmnm o o m ¢¢.o m¢.H u u mH¢H ¢.~mo¢ o o n n quH ¢.¢nm¢ o o q mm.o «5.0 n a omoH o.ummm o o a a HmcH m.qwmm o o m mo.o 0H.o n u «no N.oo- o o u a who o.oo- o o N mn.o H¢.~ u a mm¢ m.mH¢H o o - u a qu w.m¢mH o , o H .‘x- hma\z ammem humus hmn\um muumoz uoom muoumz pooh .oz madam use; 35-x was; 35...» “c2082. .wammmmw moumnHvuooo doauHmoN . .oomH umsma< o vow hHah om so voho>ham moxmum unoao>oz uuauaoudmwmz oomH u H uuwm A Nanmmm¢ MOHumm oH mzH mHHhQMm UZOH< mHZmEMMDmQz mupz coHuouuHm wx Hufloon> mouwchuooo dOHunom uonfiounom NH and hHsh nu no coho>u5m moxmum uamao>oz muauaousmmuz H oaH I N uumm GLOSSARY Arched bands. See wave-bands. Ablatibn. The wasting or surface-lowering of a glacier by e combined processes of melting, evaporation, and sublimation. (Also some avalanching and calving.) Bergschrund. The crevasse occurring at the head of a glacier or margins of an icefield, which separates the moving firn and ice of the glacier from the relatively immobile firn and ice adhering to the headwall or nunatak. This crevasse commonly penetrates to the headwall or bed of the glacier. It usually has a lower lip on the down- valley side. Bubbly glacier ice. The main material of glaciers variably containing air pockets and entrapggd water bubbles, and having a density approximating 0. -0.90 gm/cc. Cirgue. A.deep, steep-walled ”amphitheater” or recess in a mountain, caused by glacial erosion. Depth-hear. Stratum of relatively softer autumn "snow" lying Just above the annual ablation surface, characterized by low density and cupshaped crystals. Dia enesis. Alprocess of across-stratum changes which take place in Iirn due to accumulation above it, or perco- lation of rain and melt-water through it; e.g., compaction and recrystallization, the latter by metamorphismsnd refreezing, Firn. Compacted, granular, but still pervious material metamorphosed from old snow, and in transition to glacier ice. Characterized by a density approximating 0050-0075 gin/CC 0 Forbes' bands. See wave-bands. lcefold. .A fold of ice, anticlinal in shape, with its long axis across glacier in the lower Vaughan Lewis icefall. Mean névéLline. The average elevation of the névé-line taken over a period of 10 years. Névg. The net accumulation area of a temperate glacier. 131 132 Néve-line. The elevation of the most stable pos tion of the lower limit of firn or the neve. The demarcation line dividing the areas of net accumulation and negative dissipation or wastage. Ogive. See wave-band. Regime. The materialknuance (budget) of a glacier involving the total accumulation and the gross wastage in one or more budget year. The long-term state of health of a glacier. Seasonal neve- line.‘ The elevation of the lower geographical lImTt of the firn or neve at the end of a Specific ablation season. Usually the year involved is prefixed. Wave-band. The curved light and dark bands, arched or convex in plan view downglacier, that in cross-section have surface wave length and amplitude and are found below icefalls on some glaciers. Actually these also include a pattern of englacial folia which become accentuated downglacier by the process of ablation. The accentuation of the ogive character (Plan) parallels the attenuation of the surface wave (cross-section), hence these terms can be used together or separately. However, where the wave character dominates,the term wave-band is applied; and where the inlaid structures dominate, the term ogive is applied. The term arched bands is sometimes applied for general reference, where it is desired not to detail the geometry of the plan view. The descriptive term Forbes' bands is general, and applies to the feature as a combination of wave-bands and ogives (arched bands). Have-ogive. Same as wave-band but more pointed in plan view. White-ice. White, fine- -grained, non- -foliated glacier ice that is in sharp contrast to fabric- oriented bubbly glacier ice. , White-ice anticline. The surface expression of two white- ice layersfithat Join and continue as a single layer thus giving a "canoe-shaped” or eroded anticlinal appearance. White-ice layer. The near vertical inlays of white-ice found associated with ice folds in the icefall and in the wave-bands of the Vaughan Lewis Glacier. "1111111111 ”1117111111 15