. -nw . . I ll Ll mu; llzllfllflllll in in 11! will" Ill in"; II This is to certify that the thesis entitled Niagara Pinnacle Reefs of South Central Michigan presented by Frank E. Walles has been accepted towards fulfillment of the requirements for MaSte I'S (levee in GeO'OgY Major professor Date JUIX 3) 1980 0-7639 SUPPLEMENTARY - MATERIAL fin ghelued gcfatm’t'dy rm“ PLACE N RETURN BOX to remove“. checkout from your record. DATE DUE DATE DUE DATE DUE NIAGARA PINNACLE REEFS OF SOUTH CENTRAL MICHIGAN by Frank E. Walles AN ABSTRACT OF A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Geology 1980 ABSTRACT NIAGARA PINNACLE REEFS OF SOUTH CENTRAL MICHIGAN by Frank E. Walles Twelve maps were constructed (2 structure, 3 lithofacies and 7 isopach) of the units of the Niagara and Lower Salina. A north-south stratigraphic cross- section was also constructed. Through careful examination of the maps, a number of conclusions were made concerning the depositional history and environments of deposition during the Niagara and Lower Salina in the defined area of study. In the center of the area of study, a distinct widening of the Niagara isopach contours occurs. Reef debris is likely to have been funneled basinward by several submarine channels in the barrier reef in this area. The massive barrier reef and the pinnacle reefs grew to their near full height by the end of Niagara time. With the resulting isolation of the Michigan Basin accompanied with arid conditions, the A-l Evaporite was deposited. Deep water (>50) deposition of the A-1 and later evaporites occurred in the central basin area simultaneously to shallow water ("sabkha") deposition of basin margin evaporites. A rise in sea level during A-l Carbonate time resulted in minor supratidal algal mat deposition on the pinnacle reefs. Late carbonate (A-2) and evaporite units (A-2 and B) were deposited similarly to the younger A-l units. Differential subsidence throughout Niagara and Lower Salina time is well exhibited by the relation of thickness of these units along the Lucas Monroe monocline which enters the eastern half of the study area. The eastern half of the study area is shown to have subsided more rapidly than the western half of the study area. DEDICATION I would like to dedicate this study to my entire family, and especially to my Mother and Father (Carrie A. and Wilhelm E. Walles) for all of the support and faith they have given me throughout my life. For without their guidance and love, this study could not have been even begun. I wish to thank my parents for all of the good influence they have exerted on me through the years. ACKNOWLEDGMENTS Special thanks and deep appreciation go to Dr. James H. Fisher for his help, his support, and his friendship he has given me in this study. I would also like to express my appreciation to the other committee members, Dr. Duncan F. Sibley and Dr. F. W. Cambray for their time and help. I am also very grateful to Jack Oswald of Tenneco Oil Company for his generous financial support of my thesis and graduate studies. I would also like to express my thanks to the Michigan Geological Survey for the use of their facilities and data. Finally, I would also like to thank my fellow graduate students and all those people around the Geology Department (especially Loretta Knutson for her many hours of typing and retyping my thesis). iii TABLE OF CONTENTS LIST OF FIGURES . LIST OF PLATES INTRODUCTION. General History. . . . . . . . . . ...... Purpose and Scope of Study. . . . . . . . . . . . Method of Study . ...... . . . . . ..... Previous Work . . . REGIONAL STRUCTURAL SETTING . GENERAL STRATIGRAPHY AND SEDIMENTATION . DESCRIPTION AND DISCUSSION OF MAPS . Clinton Structure Map . . . . . . . . . ..... Clinton Isopach Map . ..... . . . . . . . . . . . Niagara Isopach Map . . ..... Salina A- 1 Evaporite Isopach and Lithofacies Maps . Salina A- l Carbonate Isopach Map. . . ...... Salina A- 2 Evaporite Isopach and Lithofacies Maps Salina A- 2 Carbonate Isopach Map. . . Salina A-2 Carbonate Structure Map . . . Salina B-Unit Isopach and Lithofacies Maps . PETROLEUM PRODUCTION . . Reference Key to Producing Niagara Pinnacle Reefs . CONCLUSIONS . BIBLIOGRAPHY . .33 .45 19 23 23 25 26 36 40 .42 44 .48 51 55 .60 LIST OF FIGURES Niagaran Depositional Environments . Area of Study . Stratigraphic Section with Typical Gamma— —Ray Curve of StudyArea.................... Regional Stratigraphic Cross Section . Michigan Basin and Surrounding Structural Elements Profile Through a Northern Michigan Pinnacle Reef. Depositional Model of the Niagara, A- l Evaporite, and A- l Carbonate in the Pinnacle Reef Trend . . . . . . . . Producing Niagaran Pinnacle Reefs of South Central Michigan......... 10. ll. 12. 13. LIST OF PLATES (In Pocket) Cross-section (South to North Across the Central Michigan Basin) Structure Map - Clinton Isopach Map - Clinton Isopach Map - Niagara . Isopach Map - A-l Evaporite Lithofacies Map - A-l Evaporite . Isopach Map - A-l Carbonate . Isopach Map - A-Z Evaporite Lithofacies Map - A-2 Evaporite ISOpaCh Map - A-2 Carbonate Structure Map - A-2 Carbonate Isopach Map - B-Unit Lithofacies Map - B-Unit vi INTRODUCTION General History The Niagara pinnacle reefs of South Central Michigan have recently become significant producers of oil and gas. During 1974 total annual production of oil from all zones for the entire state of Michigan was 18,101,812 barrels. The cumulative annual production from the South Central Michigan pinnacle reefs during 1974 was 1,145,000 barrels of oil. By the end of 1978 total cumulative production from the South Central Michigan pinnacle reefs had jumped to 18,667,566 barrels of oil. Comparable increases in the production of natural gas have also occurred. Presently oil and gas production from the South Central Michigan Niagara pinnacle reefs is obtained from 71 producing reefs. This can be compared to the approximately 400 producing reefs in the Niagara Pinnacle Belt in Northern Michigan. By comparing the production rise between 1974 and 1978 of the Niagara pinnacle reefs of South Central Michigan it can be seen that this area is being more intensely explored by the petroleum industry. Furthermore, this production rise has shown the great production potential of the Niagara and Lower Salina of the Michigan Basin. The area under study is not only of interest to the petroleum industry, it has attracted the attention of researchers world wide who are concerned with the relationship between cyclic carbonates and evaporites (Figure 1). The first producing Niagara pinnacle reef in the United States was discovered in St. Clair County, Michigan in 1927. Earlier producing Niagara pinnacle reefs had already been discovered in Canada in the late 1800's. The uuuuuu \\\\~.. k mmmmm 254m 240.755 wxh 2— mr2m2205>2u JdZOrtwOmwo 25.3 \k . . sssks sk skss\ss\\ss\s.ss . It ill-‘Uilll‘ Wm aha-sill FIGURE I (MODIFIED AFTER MANTEK1973) 3 active search for the pinnacle reefs in Michigan began in the 1950's. During the 1950's the primary prospecting tool for these pinnacle reefs was the gravity meter. This tool was initially fairly successful in locating the pinnacle reefs by the variation in the density contrast between carbonates and evaporites. However, full scale exploration did not become prevalent until the advent of sophisticated seismic investigations. The carbonate and evaporite units proved to be excellent reflectors, once the problems of the Michigan glacial drift were overcome. The combination of both gravity measurements with conventional and vibroseis seismology is the superior exploration method used today. In the area of study, Mobil Oil along with Michigan Gas Utilities, Amoco Production Company, and other independents such as Kulka and Schmidt, Inc., have been particularly active. During the most intense exploration which occurred along the Niagara pinnacle reef belt in Northern Michigan, Mobil Oil quietly leased up considerable tracts in South Central Michigan. Mobil Oil, with many early failures in South Central Michigan, discovered the Mason field in Ingham County in 1970 - the first of many discoveries. The potential for further production along the South Central Michigan pinnacle reef belt is evidenced by the many recent discoveries along this trend. Purpose and Scope of Study The Silurian Cayugan strata and the Niagara are well defined in the central basin area of the Michigan Basin. This well defined stratigraphic sequence occurs along the northern edge of the area of study. Niagara carbonate clearly underlies Lower Salina evaporites in the central basin. Most of the Salina carbonate units are separated by the alternating evaporites. This is not the case along the massive barrier reef trend where the evaporites wedge out. Both non-deposition and/or solution have been postulated to account for the absence of evaporites on the barrier reef. 4 Niagara carbonates are largely organic framework and detritus associated with reef platform and reef pinnacle growth. A critical question associated with these carbonates is whether reef growth had ceased throughout the Michigan Basin when the deposition of cyclic evaporites began. The age of the pinnacle reefs is important in solving this critical question. Another important question concerns the origin of the pinnacle reefs: Are the pinnacle reefs simply uncoalesced massive barrier reef, or are they associated with Middle Ordovician faulting as suggested by Shaw (1975)? In trying to solve these problems, many conflicting opinions have been offered. Mesolella et. al. (1974), Huh (1974, 1977), (3111 (1975, 1979), Jodry (1969), Sharma (1966), Felber (1964), and 51033 (1964) have suggested solutions based on geologic evidence from separate environmental complexes in the basin. It is crucial to understand, with respect to this study, that it is probable that different parts of the Michigan Basin experienced slightly different histories and that, therefore, each area must be directly studied to determine its structural and depositional history with respect to pinnacle reef growth. A regional study of Niagara pinnacle reefs by Mesolella et. al. (1974), established the general pinnacle reef belt in Michigan. Later research by Gill (1975, 1979) and Huh (1974, 1977) furnished detailed reef descriptions and a better definition of the reef belts in both northern and southeastern Michigan. However, the productive pinnacle reefs of south-central Michigan (Figure 2) have received little attention as compared to the northern pinnacle reefs, and they are anomalous with reference to the rest of the reef belt. The barrier reef in south- central Michigan has a series of major reentrants which may represent submarine reef channels. The 200 to 300 foot interval on Niagara isopach maps widens considerably opposite the reentrants. The belt of pinnacle reefs swings away from the barrier reef and has a convoluted trend which is unlike the remainder of the reef belt in Michigan. CNAllIVUI ; "”00! IS“ ' mourn: “RNA 0 mum orsroo mum» f cum nun“ ammo oscooa “com Mum mm! mnmu mm» Immune taco-non 0“,.“ Iosco ”son lAI! oscrou can «Am urcom mum manna uomcam manor "I" Ginsu IONIA cumon mun Auto“ ”In won mom: I my I van m I numzool cum mason "A I _— _ m FIGURE 2 AREA OF STUDY 6 The primary thrust is to determine how the depositional environment has influenced reef location and petroleum production. In addition this study will hopefully give some indication as to the deep vs. shallow water origin of the marginal Salina evaporites as determined for south-central Michigan Method of Study The successful mapping and correlation of seven different stratigraphic and lithologic units of the Niagara and Lower Salina in the area of study was a major goal of this study. Conventional geologic procedures were used in gathering the data. All data were derived from reports of subsurface drilling operations for oil and gas and include information derived from geophysical logs; principally: Compensated Neutron, Formation Density, Borehole Compensated Sonic Log- Gamma Ray, Dual Laterolog, Gamma Ray-Neutron, and Neutron Porosity Logs. Descriptive logs and drillers logs were used to help verify data. The State Survey and the Michigan State University collection of logs was the major source for the geophysical and mechanical logs. The Gamma Ray log, in conjunction with either a Sonic or Density log, was the most consistent and accurate source for picking formational tops. The Sonic and Density logs had as an advantage the distinct separation of carbonates and evaporites. The separation of these evaporites and carbonates was crucial to this study. Another 109 which gave fairly reliable separation of these cyclic units was the Neutron Porosity log. The Neutron Porosity log is useful for looking for porosity changes which are generally well defined when comparing evaporites and carbonates. The study was not simply a separation of evaporite and carbonate units. It included the separation of quite comparable carbonate units when the evaporites disappeared as they reached the basin margin. Consistent picking of the Gamma Ray response was a major method of combating this unit separation problem. 91.». 8 UNIT : A-2 C n: A'ZE ; f: M c M E g -NIAGARA CLINTON FIGURE 3 STRATIGRAPHIC SECTION WITH TYPICAL GAMMA-RAY OF STUDY AREA 8 It is important to note that this study is based on lithostratigraphic units, not on time stratigraphic units. Correlations are based on similar lithologies and of gradation of facies which are rock stratigraphic. The formational tops picked are comparable to those of Lilienthal (1978), Fisher (1973), Autra (1977), and Fincham (1975). Overall these tops were quite consistent in the area of study (Figures 3 c3: 4). Over 600 geophysical logs were used in the study. Twelve maps were plotted using the data gathered. The data collection included the measurement of the stratigraphic units by thickness, by elevation and by lithology. An isopach map was constructed of each of the seven units studied. Isopach maps were used in helping to determine the depositional environment and distribution of each unit. Structure maps of the Clinton shale and the A-2 Carbonate were constructed to determine whether any structural control existed on any of the units under study, especially the Niagara pinnacle reefs. Lithofacies maps of the B-Unit, A-2 Evaporite, and the A-l Evaporite were constructed to determine what control, if any, existed with respect to the pinnacle and barrier reefs of the Niagara. Oil and gas production, with respect to the Niagara pinnacle reefs, was plotted on each map to help determine the trends of production with respect to structure, thickness, and lithofacies of the units. On each map, the 300 foot isopach line of the Niagara barrier reef was plotted. This barrier reef limit is as defined by Fisher (1973). Once all of the maps were contoured and studied, ideas and conclusions were developed as to the different depositional and lithologic trends. An overall view was developed based upon the 12 maps, the stratigraphic cross- section, and related research. It must be remembered that in a detailed study of such a large area, as in this study, that the best data are obtained from geophysical logs. With geophysical logs, the problems of sample lag, lost samples, sample mixing and lost E 1% ’ [no ‘31-! 10 circulation do not occur. Cores are useful in a general standpoint for this study; however, core descriptions were much more available than the cores themselves. In general, systematic core coverage was not available for this study. A north-to—south stratigraphic cross—section was constructed using Compen- sated Neutron Formation Density logs. The cross-section gives a detailed type log for each of the environmentally important areas of the study. They include: deep basinal, pinnacle reef, interreef, and barrier reef. The cross-section illustrates the pr0posed model for the growth sequence of the Niagara pinnacle reefs and the surrounding Lower Salina units of south-central Michigan. The cross-section shows the value that the geophysical logs have for research and petroleum exploration. Previous Work The Silurian strata of Michigan have been intensely studied over the years. The first definition of Silurian subsurface stratigraphy in the Michigan Basin was by Landes (1945). He divided the Salina into eight units (A-H) and included a regional study of these units. Evans (1950) further subdivided the A unit into four separate units which we presently use in the Michigan Basin. Works by Cummings and Shrock (1928) and Lowenstam (1950) provided early, detailed faunal descrip- tions of Niagara reefs which created the base for further studies. Further contributions to the general understanding of the regional stratigraphy and paleogeography of the Middle and Upper Silurian were published by Cohee (1948), Ailing and Briggs (1961), Melhorn (1958), Ehlers and Kesling (1962), Pounder (1962), Ells (1967, 1969), Burgess and Benson (1969), Huh (1973, 1977), Briggs and Briggs (1974), Shaver (1974), Mesolella et. al. (1974, 1975), Meloy (1974), Mantek (1973), Gill (1975, 1977), Potter (1975), Nurmi (1975), Sears et. al. (1979), and Autra (1977). Stratigraphic relations of carbonate rocks of Niagara reefs and of the strata of the lower Salina Group in southern Michigan were studied by Felber 11 (1964), Sharma (1961, 1966), Jodry (1969), Ells (1960, 1962, 1969), Gill (1973, 1977), Johnson (1971), Kiddoo (1962), and Fincham (1975). Controversial studies include those by Gill (1973); a detailed study of the Belle River Mils pinnacle reef in southeastern Michigan, and by Huh (1973), who provided an in-depth study of the northern Michigan pinnacle reefs. Three basic models have been proposed, called Models 1, II, and III to try to explain the growth sequence of the Michigan pinnacle reefs. Models 1 and III are presently the most popular models among geologists today. Good explanations and comparisons of the three models are illustrated in work done by Fincham (1975) and Mesolella et. al. (1974). Model I proposes that the major growth of the pinnacle reefs occurred during the Niagara and that the alternating carbonates and evaporites occurred after the pinnacle reefs had grown to almost full height. This model proposes that reef growth had stopped during the deposition of evaporites. In-depth studies by Gill (1973) and Huh (1973, 1977) generally support this model. Model I depicts the pinnacle reefs as having been fully developed to a height of several hundred feet during Niagara time. The presence of Pentamerus sp. (Wenlockian or older) 8 well as Ludlow age fossils within the pinnacle reefs is consistent with this model. Model II proposes that the pinnacle reefs are simply lateral facies changes within the cyclic Lower Salina interreef sequence. Therefore, the carbonates of the pinnacle reef are facies changes of cyclic evaporites and carbonate. This means that while marine organisms were forming the framework pinnacle reefs, extensive halite deposition was taking place in the deeper interreef areas. While Model I depicts hundreds of feet of depositional topography, Model II proposes minimal depositional topography. Based on earlier work by Jodry (1969) in St. Clair County, Mesolella et. al (1974) proposed a third model (Model III) for the depositional sequence of the 12 Niagara pinnacle reefs. Model III has been favored in the regional studies performed by Fincham (1975) and Autra (1977). Model III supports the idea that a separate growth stage of the pinnacle reefs occurred during A-l Carbonate time. Mesolella attributed from 10' to 150' of the pinnacle reefs to A-1 Carbonate sedimentation. An actual rejuvenation of the pinnacle reefs must occur for this model to be accepted. The paleontological evidence mentioned by Mesolella includes the presence of Niagara-Salina brachiopods (Howellella smith waite) in the upper algal zone and above that, the later Salina brachiopods (Howellella corallinensis grabau). It is important to understand that these fossils are only in the top portions of the pinnacle reefs and that the exact age relationship has not been determined. The presence of A-l Carbonate age organisms on the reef crest is not enough evidence to support the idea that a full rejuvenation of the pinnacle reefs occurred. The pinnacle reefs are simply overlain by younger sediments that have been affected by the original pinnacle reefs. Evidence required for the support of model III should include unconformities in the pinnacle reefs associated with A-l evaporite time. As shown by this study and the work of Huh et. al. (1977), definite A—l Carbonate sediments do overlie the pinnacle reefs. But they are primarily tidal flat sediments, and probably not a major organic pinnacle regrowth sequence. The primary growth sequence did occur during the Niagara. It is highly likely, however, that depending on the local rate of subsidence and local environmental conditions that variations in the pinnacle reef growth sequence do occur. This is demonstrated by the work of Gill (1973) on the Belle River Mils pinnacle reef in Southeastern Michigan. He found thaat there was no A-1 Carbonate on the reef crest and that debris from the reef crest occurred below the A-l Evaporite on the reef flanks. This proved, in this case, that this pinnacle reef was entirely Niagara in age. Gill also showed that the A-1 13 Evaporite flanked the lower areas of the pinnacle reef which possibly suggests that exposure of the pinnacle reef during A-l evaporite time. Mesolella et. al. (1974) allows the lower portions of the pinnacles to be surrounded by A-l Evaporite in Model 111. Huh (1973) found a similar situation as Gill (1973) in the northern pinnacle reefs, but also found that a thin tidal flat section of A-l Carbonate covered the reef crests. The evaporite facies relationship of the A-1 and A-2 Evaporites have important effects on the growth and production capabilities of the pinnacle reef belt. Fisher (1973) and Mantek (1973) have described the reef trend and its relationship to the salt zero line of both of these evaporites. In certain areas in the Michigan Basin, this contact determines the type of production and possibility of production. Many reefs found in North America have a direct application to the Niagara pinnacle reefs of south-central Michigan. Fuller and Porter (1969) and Klingspor (1969) have described a Devonian reef and evaporite sequence in the Williston Basin which is very similar to that of the Michigan Basin. The Michigan Basin reefs have been compared to those in the Illinois Basin where the reefs are believed to be of later Silurian age. Major works on evaporite and carbonate sequences include those by Dellwig and Evans (1969), Goldsmith (1969), Scruton (1953), Kinsman (1969), Raup (1970), King (1947), Schmaltz (1969), and Fisher (ed., 1977). Studies of the Silurian salt sequence of the Michigan Basin by Dellwig and Evans (1969) and Schmaltz (1969) imply a deep water origin of the evaporites. Salt precipitation is thought to occur when the brine concentration becomes supersaturated with respect to a particular salt. $1033 (1969) and Raup (1970) propose the existence of layered solutions where, if the hypersaline brine underlying a less saline brine becomes suddenly exposed to subaerial evaporation, 14 massive halite deposition can occur. A mechanism for this exposure could involve high winds pushing less saline brines from the dense hypersaline brines underneath. Raup (1970) has shown that the mixing of a bottom layer 94% MgCl2 solution and a top layer of 94% NaCl solution will create rapid salt precipitation. Shallow water deposition of evaporites has often been the most popular model. Simple evaporation concentrates brines in shallow areas with the resulting deposition of evaporites. This has become the most popular model because at the present time no one has identified a locality where large scale deep water precipitation of salts is occurring today. The modern environments of gypsum, anhydrite and halite deposition is in the supra-tidal and "sabkha" environments such as those found in the Persian Gulf (Kinsman, 1969; Shearman, 1971). The shallow water limit for the deposition of evaporites is believed to be in water depths of less than 50 feet. It has been argued that the present day areas of evaporite deposition are very small in comparison to the Michigan Basin and other basins where masive evaporites have been deposited. Nurmi (1974) advocates a sabkha-like environment for the Michigan Basin based on the sedimentary features observed in the Goderich Salt Mine of Ontario, Canada. The sedimentary features observed include ripple marks and many minor unconformities. An important fact is that the mine is located on the basin margin. This does not rule out the possibility of deep water deposition of evaporites in the central basin area. It is possible in a hypersaline basin to have sabkha-like deposition of evaporites on the basin margin along with deep water deposition of evaporites in the deeper central basin area. Important controls of this process are the confinement of the basin and the degree of salinity that is reached. A model is needed to explain thick evaporites in the basin center with contemporary thin evaporites on the basin rim. In the Michigan Basin, the control of evaporite deposition appears to include the rate of subsidence of the basin along with the continuous input of sea water into 15 the basin. High temperatures and high aridity are generally believed to have controlled the deposition of evaporites, whether they are of shallow water or deep water origin. REGIONAL STRUCTURAL SETTING The area of study, south-central Michigan, is located in the geologic structure known as the Michigan Basin. The Michigan Basin is defined as an intracratonic or autogeosynclinal basin. The Michigan Basin is centered on the Lower Peninsula of Michigan and includes portions of adjoining states (Fig. 5). The area of the Basin is 122,000 square miles (316,000 square kilometers). The Michigan Basin is surrounded by important positive structures which have influenced its sedimentational history. The basin is bounded on the north and east by the Canadian shield; on the south by the Findlay and Kankakee Arches; and on the west by the Wisconsin Arch and the Wisconsin Dome. During Niagaran and Lower Cayugan time these structures were inactive and of very low relief. The Michigan Basin includes a number of fault patterns, joint systems and subordinate structures of interest. A strong northwest to southeast trend of these structures suggests a dominant structural control on their origin. In southern Michigan the trends change from a clear north-south trend to a northwest to southeast trend. This could suggest a mechanism of basin faulting related to subsidence of the basin interior. This pattern includes such areas as the Albion- Scipio trend and the Howell-Northville Anticline which are present in southern Michigan. Early researchers believed that the Precambrian basement controlled these structural patterns (Pirtle, 1932). Cohee and Landes (1958) proposed that these structures came from minor folding throughout the Paleozoic with the major diastrophism occurring in the Late Mississippian. Shaw (1975) believed that Mid-Ordovician faulting had controlled the orientation and geometries of the Niagara reefs. He proposed that local tectonic activity as expressed by the Mid-Ordovician faults controlled the petroleum productivity, the lithologic constituents and the pinnacle reef height by differential subsidence. His conclusions held only for the pinnacle reefs and with 16 I7 ‘2‘ A I I‘ I I O ‘\ . 4- I t I : \ I I ‘\ Q‘ ‘ y. . - L'Lssqnsm \ ILL TFO} ' ' \\\\\ mm..- W t. - -... mm“! on homo MI '4'. _+—— magnum.» 1 ....- — m 0' ”new on. I . ‘I' \ | I . q-rv-n-n- 'MJow" anon-mm no \\ hv-uum Am ‘ I v' “ out. from I )1 ' ' . I Onto, cu Ito-.0000 . N“ I _k 00-. I!" .8000“. A... In! In! ”on mum“ macro In Inn at who...» an um. not out. a“ mom-QM“ o. I tum-.IOI ' Lump" Ion \1’2. ‘9 1., :- ‘\ M08. .01. NOMI- \\ \ MICHIGAN BASIN C'TM’I mu MICHIGAN BASIN AIID SURROUNDING STRUCTURAL ELEMENTS FIGURE 5 (AFTER ELLS 1959) 18 no reference to the barrier reef. The difference between the northern pinnacle reefs and the southern pinnacle reefs can be due to subregional structural influences (Shaw, 1975). Newcombe (1933) and Ells (1966) state that southeastern Michigan has been deformed structurally to a greater extent than the rest of Michigan. The Howell Anticline in southeastern Michigan (Newcombe, 1933) and the Washtenaw Anti- clinorium, also in southeastern Michigan (Ells, 1966), consist of folds and faults of high amplitude. These folds and faults are said to be of Silurian origin. The Chatham Sag is also believed to have been active at the end of the Silurian. This Silurian tectonism which was more active in northern Michigan could have created variations in water depth which could, therefore, explain the differences between the northern and southern pinnacle reefs and provide an answer for the cyclical nature of the carbonates and evaporites. It is important to note that both the northern and southern areas have the same cyclical nature of carbonate and evaporites deposition. Differential subsidence of each specific reef tract could control the effective elevations of the pinnacle reefs and thereby control the relationship of the lithologic units with respect to the pinnacle reefs. However, the controls are probably environmental; such as, rate of water influx or local energy conditions. Thus, according to Mesolella et. al. (1974), the A-1 Carbonate would be deposited in the north to a greater extent over the pinnacle reefs as compared to the deposition only around the pinnacle reef edges in the southeastern Michigan area. Cohee and Landes (1958) proposed that the basin underwent its greatest subsidence during the deposition of the Salina and Bass Islands units (Late Silurian) and during Detroit River time (Middle Devonian). This is evidenced by the great thicknesses of the units. However, because these units are mostly evaporites, the possibility exists that very rapid deposition took place in an already existing deep 19 basin. Evidence for the rapid subsidence theory includes the existence of a pseudohinge line along the northern pinnacle reef trend and of the thinning of the Salina F Salt along the Howell Anticline in southern Michigan (Paris, 1977). The massive growth of the barrier reefs during Niagara time helped to isolate the Michigan Basin from the surrounding seas. However, several major channels were maintained between the basin and the open sea. In the area of study, the existence of a major reentrant in the barrier reef is proposed. In the southeast, the Chatham Sag and the Midland Trough helped maintain circulation to the Appalachian Basin area. In the southwest, the Battle Creek Trough was a major link to the Illinois Basin (Melhorn, 1958). A major inlet termed the "Artic Seaway" by Briggs (1958) entered through the Georgian Bay area of Ontario, Canada. According to Fisher (1973), another major northern inlet is the Grand Traverse Bay area of Michigan. GENERAL STRATIGRAPHY AND SEDIMENTATION The stratigraphic succession in the Michigan Basin includes sedimentary units ranging in age from probable Precambrian sediments through Pleistocene glacial deposits. No Permian, Triassic or Cretaceous sediments are represented in the Michigan Basin. Of the total sedimentary thickness, fully 31% is of Silurian age (Ells, 1969) and one-third of these are evaporites. Niagaran rocks (Middle Silurian) are exposed in the southern part of the Upper Peninsula of Michigan, in southwestern Ontario, northwestern Ohio, northern Indiana, northeastern Illinois and eastern Wisconsin. Niagaran strata are within 550 feet (165 meters) of the ground surface in the southeastern and southwestern parts of Michigan. In northern Michigan, depth to Niagaran rocks ranges from 3800 feet to more than 7000 feet (Huh et. al., 1977). In south-central Michigan, the depth to Niagaran rocks ranges from 1500 feet to 3700 feet. The Niagara Group is composed of the Burnt Bluff, Manistique, Lockport, and Guelph formations (the Guelph is considered to be a reef facies of the Lockport). These formations are equivalent to the "Clinton", "White Niagara", "Gray Niagara", and "Brown Niagara" in the informal terminology of the oil industry. For convenience in this study, the "White", "Grey", and "Brown Niagara" are lumped under the term "Niagara." The "Brown" Niagara is equivalent to the Geulph formation. The Geulph formation is composed of the organic skeletal wackestones of the biohermal stage and boundstone of the organic reef stage of the pinnacle reefs. The barrier reef platform bank (Meloy, 1974) is composed of stromatoporoids, coarse-to medium-grained dolomite and arenitic wackestone. The Manistique formation is equivalent to the "Clinton" which consists of about 20 feet of light colored dolomitic carbonates and shales. According to Autra (1977), the Clinton thickens to about 400 feet of clean, cherty dolomite in northern Michigan. The whitish-gray to brownish-gray lower Lockport (White Niagara 20 21 grades into gray in the Upper Lockport - Gray Niagara). Toward the basin center, the Lockport becomes a hematitic red. Toward the basin margin, the Lockport is more than 300 feet thick in the barrier reef carbonate bank. The pinnacle reefs are located along a shelf area on the basinward side of the barrier reef. In south-central Michigan, the pinnacle reefs can attain thicknesses of up to 500+ feet. The Niagara is represented primarily by dolomite in the pinnacle and barrier reef trend and limestone in the more basinward facies. However, some basinward pinnacle reefs are composed of limestone. The Salina Group overlies the Niagara Group. At the crests of the pinnacle reefs, supra-tidal, island algal stromatolites of the lowermost carbonate unit of the Salina Group is represented (Huh et. al., 1977). In the basinal and interreef areas the Salina Group consists of cyclical evaporites, limestones, and dolomites divided into A-1 Evaporite, A-l Carbonate (Ruff formation), A-2 Evaporite, A—Z Carbonate, B-Unit evaporite, C-Shale, D-Salt, E-Unit (Marl and Dolomite), F-Salt and G-Unit (Landes, 1945; Evans, 1950; Ells, 1967; Budros and Briggs, 1977). This study is only concerned with the Lower Salina, B-Unit evaporite through A-l Evaporite. During the Lower Salina, alternating carbonates and evaporites were deposited with mainly anhydrite and dolomite being found in shelf and pinnacle trend areas and limestone and salt in the central basin areas. The thick barrier reef bank growth during the Niagara set the stage for deposition of the alternating evaporites and carbonates. The restriction and isolation of the basin from surrounding seas is greatest at the end of the Niagara (Dellwig, 1955). Barrier reef growth was important in restricting the basin to the point where thick cyclic evaporites could be deposited. A general thickening trend of the B-Unit Evaporite, A-2 Evaporite, and the A-l Evaporite toward the basin center and thinning toward the basin margins are 22 observed. The A-l Carbonate, A-2 Carbonate, and the Niagara show the opposite trend, thickening toward the basin margin and thinning toward the basin center. The cause for this is believed due to the intense biologic control of the carbonate units. According to Autra (1977) the total thickness of the units involved in this study (B-Unit through Clinton) varies from less than 600 feet along the basin margins to over 1500 feet in the depocenter of the basin. The thicker basinward sediments include almost 1200 feet of evaporites which are mainly salt. The depocenter for the Upper Silurian is in the Saginaw Bay area of the Lower Peninsula of Michigan. There are three basic models that try to explain the sequence of sedimen- tation of the Niagara and Lower Salina Section. Model I makes use of a relatively shallow basin that develops major reef growth along its margins which then becomes rapidly isolated followed by rapid subsidence in the basin interior. During this subsidence, thick evaporites accumulate and fill in the basin. Model II proposes an existing deep central basin and sea with shallow margins. As the barrier reef belt grows, the isolation of the basin becomes greater, thereby accumulating heavier brines in the central basin. With an arid climate, these hypersaline brines precipitate the evaporites. Deep water origin of evaporites is critical for this model. The evaporites are proposed to be simply lateral facies changes of the carbonates that make up the barrier and pinnacle reefs. Model III also makes use of a pre-existing deep water basin, with restriction by reefing on the shallow basin margins along with an arid climate at the beginning of the Salina. Importantly, Model III proposes a "sabkha" and desication model for the basin rim evaporites and a deep water origin for the central basin evaporites. It can be seen that all three models have merits and 23 demerits. Models I and 111 could possibly occur in different environmental sections of the Michigan Basin. An overall important control appears to be the rate of subsidence of the particular area. For anyone not familiar with the units discussed in this section, it is suggested that a study of the north-south stratigraphic cross-section would be helpful. A standard geophysical log for each environmental section of the Niagara is represented on the cross-section. DESCRIPTION AND DISCUSSION OF MAPS Clinton Structure Map The Clinton structure map (Plate 1) was constructed on a 100 foot contour interval. The Clinton is the lowermost unit mapped. Availability of data was generally good; however, many of the wells drilled into the pinnacle reefs did not test the entire Niagara reef section. A good understanding of some of the features plotted on the Clinton structure map is important. Standard well symbols were plotted with respect to production from the Niagara pinnacle reefs. The stippled line across the map represents the limit of the Niagara barrier reef as defined by Fisher (1973) and Autra (1977). This barrier reef definition states that the barrier reef begins on or near the 300 foot isopach contour of the Niagara. The south-central basin outline of the Michigan Basin is well exhibited on the Clinton structure map. The elevation of the central basin area in the area of study is 4300 feet below sea level while the elevation of the basin margin area reaches 1500 feet below sea level. The slope of the basin margin area, which is located along the bottom of the map, averages 46 feet per mile. The slope of the central basin area, which is located near the top of the area of study, averages 66 feet per mile. The overall average 310pe of the basin in the area of study is 55 feet per mile. The increase in slope moving further into the basin exhibits the greater degree of subsidence in the central basin area. The slope change exhibited on the Clinton structure map is good evidence of differential basin subsidence, but not necessarily during Clinton time. In the region mapped, the area from R1W to R1E exhibits a fairly consistent basin hinge line oriented north 600 west. However, from RZE to R4E a radical change in the contours occurs. A structure known as the Lucas Monroe monocline is the source of this change. The structure appears to be made up of several left 24 25 lateral strike slip faults. According to Shaw (1975) the origin of this structure is related to Middle Ordovician faulting which has resulted in the differential subsidence of the overlying beds. The positive and negative areas located in T4N-R4E are likely offset continuations of the Lucas Monroe monocline. It can be postulated that a dip-slip relief fault trending parallel to the Lucas Monroe monocline exists in this area. Of major importance is the fact that the pinnacle reef belt and the barrier reef presently transect structure. If major subsidence had occurred during the deposition of the barrier reef, the barrier reef outline would follow closer with the structural outline of the present basin. It is well known that a continuous barrier reef grows in a stable depth of water. However, an important trend does exist in the barrier reef belt in TZN-RZE where the barrier reef noses out parallel to the Lucas Monroe monocline. Due to the lower structure surrounding this nose, we can postulate that a slight differential subsidence was occurring during Niagara (Cayugan). If subsidence was occurring during Niagara time, as evidenced by the Clinton structure map, there then could exist a slight age differential along the pinnacle reef belt. The pinnacle reefs higher on structure could be slightly older in age than those lower on structure. This is due to the idea that if the pinnacle reefs are close to the same height, both high and low on structure, the lower on structure pinnacles would have environmentally (deeper water depth) ceased to grow earlier than the structurally higher pinnacles. Some slight widening of the structure contours does occur along the central area pinnacle reefs. This widening could be the remains of a former stable shelf area meaning that the pinnacle reefs were located on a somewhat broader shelf area as compared to the rest of the basin. In the center of the area of study, the major pulling back of the barrier reef outline, with respect to the expected trend, appears to parallel structure. The 26 water movement of the postulated reentrant has moved across structure. This gives further evidence for the existence of some structural control during the Clinton and Niagara. The comparison of the northern pinnacle reef belt to the south-central pinnacle reef belt, with respect to Clinton structure, shows that the northern reef belt lies 2000 to 3000 feet deeper than the south-central reef belt. This difference exhibits the differential basin subsidence that has occurred within the Michigan Baisn. According to Fisher (1977) and Autra (1977) the highest degree of subsidence occurred during the Silurian and Devonian periods. Clinton Isopach Map The Clinton isopach map was constructed on a ten foot contour interval. The Clinton is the oldest unit mapped in this study. The Clinton is a shale and carbonate unit that lies directly below the Niagara carbonate reef. The reason for the isopach mapping of the Clinton was to determine whether the Clinton exerted any control on the location and type of production of the Niagara pinnacle reefs. According to core descriptions, the Clinton, as represented in the area of study, is composed of a thin gray shale and finely crystalline, hematite stained dolomite sequence. According to Autra (1977), the Clinton thickens to over 400 feet in the area of the northern Michigan pinnacle reefs and its lithology changes to a massive cherty dolomite and limestone. The Clinton, as contoured in the area of study, shows a slight thickening from 20 to 40 feet in thickness toward the central basin area. Along the entire shelf area which includes the pinnacle and barrier reefs, the Clinton appears to have very little meaningful control. No apparent structural control other than a slight thickening basinward occurs during Clinton time. Therefore, it appears that 27 the Clinton exerted no control on the location or production of the pinnacle reefs. In the area of study, Clinton time was a period of stability. Niagara Isopach Map The Niagara Isopach Map (Plate 3) was constructed on a 50 foot contour interval. Even with the detailed map that has been constructed, it was impossible to contour each individual pinnacle reef. The Niagara was contoured ignoring the pinnacle reefs; however, each producing pinnacle reef was indicated by standard production symbol employed by the petroleum industry. Where a well penetrated the complete pinnacle reef, the actual thickness of the reef was shown on the map. It can be observed from the map that the pinnacle reef belt occurs between the 150 foot contour and the 300 foot contour interval. The 300 foot contour (stippled line) is defined as the outer limit of the barrier reef (Fisher, 1973). The Niagara is an intensely biologically controlled sedimentary unit. As can be readily observed on the map, the greatest thickness occurs on the basin margin along with a thinning toward the basin center. The Niagara consists of four basic sedimentologic phases or stages: barrier, interreef, pinnacle and basinal. The barrier reef phase grew in a high energy shallow water environment of the basin margin. With continued consistent subsidence, the barrier reef in south-central Michigan grew to a thickness of over 500 feet. The thickness of the barrier reef is not constant over the area of study. The interreef phase and pinnacle reef phases occur basinward from the barrier reef. The pinnacle reefs are reefs which have grown in a more unstable or more rapidly subsiding area than that of the barrier reef. The pinnacle reefs are steep biohermal growths of carbonate sediments. The interreef sediments are carbonates composed primarily of reef rubble and fine dense unfossiliferous sediments. The fourth phase consists of the basinal Niagara carbonates which are a thin basinal, deeper water facies which covers the central basin area. By studying the north-south stratigraphic section, 28 an example of the relationships between the various units in each separate Niagara phase can be observed. According to Huh (1973), the massive barrier reef consists of coarse skeletal carbonate, abundant stromatoperoids, corals, and algal units. These units make up most of the massive reef core. Carbonate sands and skeletal allochems have been deposited within and on the slopes of the massive reef. The barrier reef consists of biostromal deposits which are overlain by biohermal deposits. This is compared to the pinnacle reefs which consist primarily of biohermal deposits in their lower sections. Framework organisms common in the barrier reef include F avosites, Halysites and Coenites. In the southern trend, the barrier reef attains widths of 50 miles (Fisher, 1973). The barrier reef along the southern trend attains, in some places, a thickness of 610 feet. In the area of study, the well control into the barrier reef is quite good due to the many oil fields (i.e., Albion Scipio) of Trenton age, which underlies the Niagara. The barrier reef has proved unproductive so far in southern Michigan. Mesolella et. al. (1974), Autra (1977) and most other researchers believe that the barrier reef is essentially all Niagara. The Salina A-1 Carbonate is thought by most Michigan geologists to pinch out along the barrier reef slopes and between the interreef passes. Fincham (1975) produced evidence that suggests that erosional unconformities occurred during A-l Evaporite time on the barrier reef and some of the pinnacle reefs. The barrier reef in most areas of the Michigan Basin exhibits a steep basinward slope and a gentle backward margin slope. In the center of the area of study a distinct widening of the isopach contours occurs indicating a more gentle slope of the barrier reef. Reef debris is likely to have been funneled basinward by several submarine channels in the barrier reef in this area. The observation of the barrier reef outline in the area of study shows that a major reentrant did exist. 29 The reentrant in the barrier reef amounts to more than ten miles from the expected barrier reef front. A lack of pinnacle reefs in this zone is further evidence for an area of rapid deposition and turbid waters unfavorable to reef growth. A submarine fan deposit of reef debris may account for this extension of the barrier reef into the basin. Earlier in the discussion, it was mentioned that some structural control occurred along the Lucas Monroe monocline. It is suggested that structural control combined with environmental factors controls the barrier reef trend. Pinnacle reefs are found between the 150 foot and 300 foot contour interval of the Niagara isopach map. Throughout the area of study, this trend carefully follows the barrier reef outline. Major breaks in the pinnacle reef belt are believed to be controlled by submarine fans and local tectonic stability. The pinnacle reef belt in northern Michigan, in comparison, is within the 200 to 300 foot contour interval, while the pinnacle reefs of the Allegan and St. Clair platforms are generally toward the basin margin from the 140 foot contour (Autra, 1977). The pinnacle reefs are located on the perimeter of the A-1 and A-2 and B-Salt basins, but are still located within the A-1 and A-2 and B-Anhydrite zones. Comparably the northern pinnacle reefs are located within the A-l, A-2 and B-Salt basins (Autra, 1977). As evidenced by the above data, the rate of subsidence within various segments of the basin are of extreme importance with respect to the determination of the depositional environment. Overall, in the area of study, differential subsidence was active in the Middle Niagara. This is based on the assumption that both the barrier and pinnacle reefs are close to the same age. Pinnacle reef growth varies from 300 to 500+ feet in northern Michigan (Figure 6). While pinnacle reefs in the area of study also vary from 300 to 500 feet they are, on the average, not as tall as their northern counter parts. Dips of the steep sides of the pinnacle reefs range between 200 to 40° on the 30 A2 CARDONATE ....._.;.; _.;. ....... ......... D O I . Al CARBONATE o no. ..... too. ..... no. ..... IO. 0000000000 ......................................... oooooooooooooooooooo .0 I o o oooooooo BROWN MAG CRINOIDAL LIMESTONE ( BOUDINAGE) . /fl///, '7’” GRAY NIAGARA'U I I / , .’/ ‘../.'/,; ,// /. M/ {/M , " /.M ’/./>;2v.’/»y:,-; /./;.--’///4.//*/ o ,. Jaw/'4; “If/IZZI/ 57441124: ;-:vW// “IV-3"? ,.//..~,-.' /,/,, - ///// ,.’/’/ //:'/’-'///" -//:/7 /’/7//' /’/' /, r/2/"'/”I’-"'v‘ ""r’-"/’-/"/”/"/ “’4'" I ' I”! //" ll"" L'I/“A’ ’l/ III ///;'//0 //Z/-Eo< cam oh cow—0.60.5 Hmma mwaa whoa whoa «Boa whoa qnma mnmfi whoa mnma mnma mhmfi mnma “baa Han chma Head Nwma Nun-$0020 am-zN-mn ”2:8 :88 sm-zN-mm 85mm :88 Bm-zN-R 83mm :88 sm-zN-Nm 83mm :88 sm-zN-B 838 :88 38283 838 :88 382.88. 838 :88 am-zN-Z 83mm :88 am-zN-k 83mm :88 26.2.8 868 382-3 228 26-3-2 .k 228 26-3-: 228 2 Bone 23.2.2 8:280 BN-zN-mm .mm .8 8:820: BN-zN-sm 8:83 23-3-: .93 3.. 23.3.2 .3 .2 .m 83 so 8:83 s m582 22... caumm acumm cme cgwm caumw cod—mm. acumm acumw confiw caofiwU cso£m0 cao£mO cao£m0 coon—m0 EmcmE Emzmcm cno£mO coon—mo Nucnoo .Cm@_50_2 —m.5C®U LuJOm-y $0 mwmmm m—OmCPZQ Ewpmmmmz mcmoDUOLQ Ou \AmVA mocmhmvmm .._.. MJm30< 000 0._. 003000000. Huaa nnma mnma whoa whoa mmma whoa NROH nnma whoa qnma qnma mnma mwma tha whoa whoa whoa 5030000 28-273 888:0 23-27.. 2.8-. .sm-mH-Nm 8-. a .800 23-3-8 8-_ 2 .800 23-07% 8-. 23-07% 8.. 23-2-8. 8-. 23-8-: 8-_ a .800 25-2-2 80 2 .800 2.872 80 2,372 8.. 23.3.3 80 2 .800 23.3.2 80 2,872 8-. 23-3-2 8.. 2 .800 25-2-: 8-. 25-2-: 8-. 2 .800 23-2-3 8-. 0030000 um 0E0Z 500.... 90.30000 .H 00m

00£D ....N-ZN-Nn .Hn .mN 8.0 832, B .800 BH-zN-mH 88> m. .800 BH-zN-mH 88> 2 .800 BH-zN-mH 88> aH-zN-NH 88> A0803: BTZN-wa >0>0> BH-zN-m 88> 0N-zH-e 882888 mN-zH-0 82.8.88 28.3.8 .8 .NN 8N 280880 2 .88 Edna-8N 38088 2.8.3.8 .mN 880880 E-mH-HN 380880 Hm. 2:00 2.N-zH-NN .HN .mH 88:80 2 2:00 2.N-zH-HN .NH .0H 88:80 SN-zH-ON 88:80 2 .800 2.N-zH-: 88:80 aN-zH-NH 88:80 0030000 8 0E02 50C 20.30000 .H 0150...- E0005 E0005 E0005 E0005 E0005 E0005 E0005 E0005 E0005 000500 000500 000500 000500 E0005 E0 005 E0005 E0005 E0005 50000 .... an on 00 mm mm mm mm 00 mm mm Ho 00 mm mm mm mm mm 0m .wmm CONCLUSION It is crucial to have understood, with respect to this study, that is is likely that different parts of the Michigan Basin have experienced slightly different histories and that, therefore, each area must be individually studied to determine its structural and depositional history with respect to pinnacle reef growth. This study has shown that the Niagara and Lower Salina of South Central Michigan has its own distinct depositional and structural history as compared to other separate pinnacle reef groups around the Michigan Basin margin. Local structural control as exhibited by the local rate of subsidence in combination with environmental controls such as basin reentrants determines the unique local depositional history of each particular pinnacle reef group. The barrier reef in South Central Michigan has a series of major reentrants which may represent submarine channels. In the center of the area of study, a distinct widening of the Niagara isopach contours occurs. Reef debris is likely to have been funneled basinward by several submarine channels in the barrier reef in this area. The reentrant in the barrier reef amounts to more than ten miles from the expected barrier reef front. A lack of pinnacle reefs in this zone is further evidence for an area of rapid deposition and turbid waters unfavorable to reef growth. Environmentally, the Niagara has been divided into four distinct zones: Basinal, Interreef, Pinnacle reef and Barrier reef. These environmental zones are exhibited in the north-south stratigraphic cross section. This cross section illustrates the proposed model for the growth sequence observed of the Niagara pinnacle reefs and surrounding Lower Salina units of South Central Michigan. The model for the growth sequence of the Niagara pinnacle reefs is basically Model I, but with major modifications. The major pinnacle and barrier reef growth occurred during the Niagara. High depositionaltopography did exist near the end 56 57 of the Niagara. The alternating Lower Salina carbonates and evaporites occurred after the pinnacle reefs had grown to almost their full height. Deep water evaporites of the central basin area occurred simultaneously with shallow water deposition of evaporites along the barrier reef margins. The A-l Carbonate did add to the pinnacle reefs crests, but not as a major reef regrowth sequence as pr0posed by Model III. Tidal flat algal mats do not constitute renewed framework pinnacle reef growth. A maximum of 60 feet of tidal flat algal mats of A-l Carbonate age do occur on the more basinward pinnacle reef crests in the area of study. Evaporites do not transect the pinnacle reefs. Evidence for deep water origin of the basinal evaporites includes the existence of very thick basinal salt which lacks sabkha sedimentary structures. High temperature and high aridity in combination with the restriction of the basin by the Niagara barrier reef was the primary mechanism for the deposition of the Lower Salina evaporites. A promising mechanism for evaporite deposition is where a hypersaline brine underlying a less saline brine becomes suddenly exposed to subaerial evaporation; through winds pushing the less saline brines from the dense hypersaline brines underneath. Little evidence of deep basement control of Niagara reefs has been found. However, mid-Ordovician faults could have been responsible for some pinnacle reef locations. Movement along the fault controlled Lucas Monroe monocline did occur throughout the Niagara and Lower Salina as evidenced by the thinning of the units studied. The Clinton structure and A-2 Carbonate structure maps have shown that extreme subsidence has occurred since Clinton and Niagaran deposition. This is illustrated by the Niagara barrier reef transcending structurally deeper into the basin. If no subsidence had occurred, it would have been expected that the barrier reef outline would follow lateral structure contours. The rapid increase in slope 58 basinward also exhibits the higher rate of subsidence that has occurred in the central basin area. It is proposed that subsidence did occur during the Niagara and that the origin of the pinnacle reefs are tied to this more rapidly subsiding interior. Differential subsidence of each specific reef tract did control the effective elevations of the pinnacle reefs with respect to sea level. This is reflected by the relationship of the lithofacies units of the evaporites positionwise with respect to the barrier reef. Due to the barrier reef outline transecting structure and the Lower Salina units overlapping the eastern barrier reef, it has been concluded that the western pinnacle reefs are therefore slightly older. This is due to the possibility that a lower rate of subsidence occurred in the western half of the area of study. The Clinton isopach map has effectively shown that the Clinton exerted no control on the location or production of the pinnacle or barrier reefs. No apparent stratigraphic control other than a slight thickening basinward occurred during Clinton time. The basinward thickening of the A-l Evaporite and its progressive facies changes which require higher brine concentrations basinward does show that subsidence did occur during A-l Evaporite time. A-l Evaporite does occur in the interreef areas, but due to elevational differences, the A-l Evaporite was unable to cover the pinnacle reef crests. Only the upper facies unit of the A-l Carbonate overlies the pinnacle reef crests. This distinction shows that the A-l Carbonate had to fill in between the pinnacle reefs until it was finally able to deposit tidal flat sediments on the pinnacle reef crests. The greatest thicknesses of the A-l Carbonate occur on the flanks of the pinnacle reefs. Importantly, the A-l Carbonate sea did not reconnect to the Illinois or Appalachian basins. This is contrary to the suggestion 59 of some geoloqists that the A-l Carbonate covers the barrier reef and connects to the southern basins. The A-Z Evaporite resulted environmentally from the lowering of the sea level after A-l Carbonate time. The rate of subsidence was slightly faster than that of A-l Evaporite time as evidenced by the thicker evaporites and the lack of sylvite deposition. This thickness could also be explained by a deposition of the evaporites over a longer period of time and by a less dense brine concentration than was characteristic of the A-l Evaporite. The A-2 Carbonate was again biologically controlled. This is evidenced by the thickest carbonates occurring in the interreef areas. Algal reef growth did occur during the A-2 Carbonate in the interreef areas as shown by the random thickening of the unit. A-2 Carbonate time included the rising of the sea level up and over the Niagara barrier reef. For the first time since Clinton time, the Michigan, Illinois and Appalachian basins were fully reconnected. Niagara pinnacle reefs are reflected in the A-Z Carbonate structure map as convoluted contours. This shows that during later differential subsidence, the pinnacle reefs behave as independently subsiding structural units. Thinning of the A-2 Carbonate over the Lucas Monroe monocline suggests positive movement along this structure. With the renewed lowering of the sea level, B-Unit evaporites were deposited. The B-Unit exhibits a unique lithofacies pattern. In contrast to the A-Evaporites, the B-Unit has its own basin margin dolomite equivalent. The B-Unit has a thickness pattern very close to that of the A-2 Evaporite and A-1 Carbonate. This pattern is that of thicker deposition in the east and thinner in the west. In the east, the Niagara barrier reef did control the lithofacies of the B-Unit so that only dolomite was deposited. This reflects the higher structural position of the eastern part of the area of study. All of the units of the Lower 60 Salina, including the B-Unit, show a progressive overlapping of the younger units toward the basin margin. This represents active basin subsidence throughout the time interval studied. Petroleum production, whether oil or gas or mixed has shown no observable depositional (other than A-l Evapi) and structural control. The random pattern of the type of production has at present no reasonable explanation. No such trend as observed in the northern Michigan pinnacle reef belt is found in South Central Michigan. Different depositional histories between these two areas offer the only explanation. The different geometries of the reefs in the area of study could have affected the type of production. It is hoped that a better understanding of the depositional and structural history of the Niagara pinnacle reefs of South Central Michigan has been accomplished by this study. With this study in hand, the location of promising areas for future exploration can be determined. The effective use of seismic in these promising areas should help narrow the search for potential pinnacle reefs. BIBLIOGRAPHY BIBLIOGRAPHY Ailing, H. L., and Briggs, L. l., 1961. Stratigraphy of Upper Silurian Cayugan evaporites: Amer. Assoc. Petrol. Geol. Bykk., v. 45, p. 515-547. Autra, M. D., 1977. A regional study of the Niagaran and Lower Salina of the Michigan Basin: Unpub. Master's Thesis, Michigan State University. Bates, E. R., 1970. The Niagaran Reefs and overlying carbonate evaporite sequence in southeastern Michigan: Unpub. Master's Thesis, Michigan State University. Bathurst, G. C., 1971. Carbonate sediments and their diagenesis: Developments in Sedimentology, v. 12, Elsevier Pub. Co., New York. Briggs, L. 1., 1958. Evaporite facies: Jour. Sed. Petrol., v. 28, p. 46-56. , and Briggs, D. Z., 1974. Niagara-saline relationships in the Michigan Basin: i_n Kesling, R. V. (ed.), Silurian Reef-evaporite facies, Michigan Basin (abs.): Mich. Basin Geol. Soc. Ann. Field Conf., p. 1-23. , and Briggs, D. Z., 1975. Petroleum potential as a function of tectonic intensity of reef-evaporite facies, Michigan Basin (abs.): Am. Assoc. Petrol. Geol. Ann. Mtg. Abstr., v. 2, p. 7. , Briggs, D. Z., and Elmore, D., 1978. Stratigraphic facies of carbonate platform and basinal deposits, Late Middle Silurian, Michigan Basin, in the north central section: Geol. Soc. Am., Field Excursions, p. 117-131. , and Budros, R., 1977. Depositional environment of Ruff Formation (Upper Silurian) in southeastern Michigan: i_n Fisher, J. H. (ed.), Reefs and evaporites, concepts and depositional models. Am. Assoc. Petrol. Geol. Stud., no. 5, p. 53- 71. Cohee, G. V., 1948. Thickness and lithology of Upper Ordovician and Lower and Middle Silurian rocks in the Michigan Basin: U.S. Geol. Surv. Prelim. Shart 33, 101 and Gas Inv. Serv. , 1965. Geologic history of the Michigan Basin: Jour. of Wash. Acad. of Sci., v. 55, p. 211-223. , and Landes, K. K., 1958. Oil in the Michigan Basin: in Weeks, L. G. (ed.), Habitat of Oil, Am. Assoc. Petrol. Geol. Catacosinos, P. A., 1973. Cambrian lithostratigraphy of the Michigan Basin: Am. Assoc. Petrol. Geol. Bull., v. 57, p. 2404-2418. Cumings, E. R., and Shrock, R. R., 1928. Niagaran coral reefs of Indiana and adjacent states and their stratigraphic relations: Geol. Soc. Am. Bull., v. 39, p. 579-620. Dellwig, L. F., 1955. Origin of the Salina Salt of Michigan: Jour. Sed. Petrol., v. 25, p. 83-110. 61 62 Bibliography (cont'd) Delwig, L. F., and Evans, R., 1969. Depositional processes in Salina Salt of Michigan, Ohio, and New York: Am. Assoc. Petrol. Geol. Bull., v. 53, p. 949-956. Ehlers, G. M., and Kesling, R. V., 1962. Silurian rocks of Michigan and their correlations: Mich. Geol. Soc. Ann. Field Excurs., p. 1-20. Ells, G. D., 1958. Notes on the Devonian-Silurian in the subsurface of southwest Michigan: Michigan Dept. of Conserv., Geol. Surv. Div. Prog., Dept. 18, 55p. , 1962. Silurian rocks in the subsurface of southern Michigan: i_n Fisher, J. H., Chairman, Silurian rocks of the southern Lake Michigan area: Mich. Basin Geol. Soc. Ann. Field Excurs., p. 39-49. , 1963. Information on Michigan Silurian oil and gas pools: Mich. Dept. of Conserv., Geol. Surv. Div., 34p. , 1967. Michigan's Silurian oil and gas pools: Rept. of Inv., no. 2, Geol. Surv., Div. Mich. Dept. Conserv., 49p. , 1969. Architecture of the Michigan Basin: Mich. Basin Geol. Soc. Ann. Field Excurs., p. 60-88. Evans, C. S., 1950. Underground hunting in the Silurian of southwest Ontario: Geol. Assoc. Can. Proc., v. 3, p. 55-85. Felber, B. E., 1964. Silurian reefs of southeastern Michigan: Unpub. Ph.D. Thesis, Northwestern University, 194p. Fincham, W. J., 1975. The Salina Group of the southern part of the Michigan Basin: Unpub. Master's Thesis, Michigan State University, 57p. Fisher, J. H., 1969. Early Paleozoic history of the Michigan Basin: Mich. Basin Geol. Soc. Ann. Field Excurs. Guidebook, p. 89-93. , 1973. Petroleum occurrence in the Silurian reefs of Michigan: Ontario Petrol. Inst., Tech. Paper 9, 10p. Fuller, J. G., , J. W., and Porter, J. W., 19698. Evaporite formations with petroleum reservoirs in Devonian and Mississippian of Alberta, Saskatchewan and North Dakota: Am. Assoc. Petrol. Geol. Bull., v. 53, p. 900-026. , 1969b. Evaporites and carbonates: Two Devonian Basins of Western Canada: Bull. Can. Petrol. Geol., v. 17, p. 182-193. Gill, D., 1973. Stratigraphy, facies evolutionm and diagenesis of productive Niagaran reefs and Cayugan Savkha deposits, the Belle River Mills Gas Field, Michigan Basin: Unpub. Ph.D. Thesis, University of Michigan, 262p. , 1975. Cyclic deposition of Silurian carbonate and evaporite in the Michigan Basin, Discussion: AAPG Bull, v. 59, p. 535-538. , 1977a. The Belle River Mills Gas Field: Productive Niagaran reef encased by Sabkha deposits, Michigan Basin: Mich. Basin. Geol. Soc. Spec. Pub., no. 2, 183p. 63 Bibliography (cont'd) Gill, D., 1977b. Salina A-01 Sabkha cycles and the Late Silurian paleogeography of the Michigan Basin: Jour. Sed. Petrol. Goldsmith, L. H., 1969. Concentration of Potash Salts in Saline Basins: Am. Assoc. Petrol. Geol. Bull., v. 53, no. 4, p. 790-797. Haxby, W. F., Turcotte, D. L., and Bird, J. M., 1976. Thermal and mechanical evolution of the Michigan Basin: Tectonophysics, v. 36, no. 1-3, p. 57-75. Hinze, W. J., 1963. Regional gravity and magnetic anomaly maps of the southern Peninsula of Michigan: Mich. Geol. Surv. Rept. Inv. 1, 26p. Hosler, W. T., 1966. Bromide geochemistry of salt rocks: Second Symposium of Salt, v. 2, p. 248-275. Huh, J. M. S., 1973a. Geology and diagenesis of the Niagaran Pinnacle Reefs in the northern shelf of the Michigan Basin: Ph.D. Thesis, University of Michigan, 266p. , 1973b. Stratigraphy and diagenesis of the Niagaran Pinnacle Reefs (Silurian) in northern Michigan Basin (abs): AAPG Bull., v. 57, p. 785. , Briggs, L. I., and Gill, D., 1977. Depositional environments of Pinnacle Reefs, Niagara and Salina Groups, Northern Shelf, Michigan Basin: i_n Reefs and Evaporite-concepts and depositional models: AAPG Studies in Geol., no. 5. Jodry, R. L., 1969. Growth and doldomitization of Silurian Reefs, St. Clair County, Michigan: AAPG Bull., v. 53, p. 957-981. Johnson, K., 1971. The interrelationship of the Lower Salina Group and Niagaran Reefs in St. Clair and Macomb Counties, Michigan: Unpub. Master's Thesis, Michigan State University, 34p. King, R. H., 1947. Sedimentation in the Permian Castille Sea: AAPG Bull., v. 31, no. 3, p. 470-477. Kinsman, D. J. J., 1969. Modes of formation, sedimentary associations and diagnostic features of shallow water and supratidal evaporites: AAPG Bull., v. 53, p. 830- 840. Klingspor, A. M. 1969. Middle Devonian Muskeg evaporites of western Canada: AAPG Bull., v. 53, p. 927-948. Landes, K. K., 1945. The Salina and Bass Islands rocks in the Michigan Basin: U.S. Geol. Surv., Prelim. Map, no. 40, Oil and Gas Inv. Serv. Lilienthal, R. T., 1978. Stratigraphic Cross-sections of the Michigan Basin: Geol. Surv. Div. Rept. of Inv. l9. Lowenstam, H. A., 1950. Niagaran Reefs of the Great Lakes area: Jour. Geol., v. 58, p. 430-487. Mantek, W., 1973. Niagaran Pinnacle Reefs in Michigan: Mich. Basin Geol. Soc. Ann. Field Excurs. Guidebook, p. 35-46. 64 Bibliography (cont'd) Mantek, W., 1976. Recent exploration activity in Michigan: Ontario Petrol. Inst., Proc. 15th Ann. Conf., 29p. Matthews, R. D., Anderson, R. J., Egleson, G. C., and majeske, E. C., 1973. The recent discovery and probably distribution of extensive deposits of potash in the Silurian in Michigan: 24th IGC, p. 445-454. , and Egleson, G. C., 1974. The origin and implications of a Michigan Basin potash facies in the Salina Salt of Michigan: 4th Symposium on Salt, Northern Ohio Geol. Soc., Cleveland, Ohio. Melhorn, W. M., 1958. Stratigraphic analysis of Silurian rocks in the Michigan Basin: AAPG Bull., v. 42, p. 816-838. Meloy, D. U., 1974. Depositional history of the Silurian northern carbonate bank of the Michigan Basin: Unpub. Master's Thesis, University of Michigan, 78p. Mesolella, K. J., Robinson, J. D., McCormick, L. M., and Ormiston, A. R., 1974. Cyclic deposition of Silurian carbonates and evaporites in the Michigan Basin: Am. Assoc. Petrol. Geol. Bull., v. 58, p. 34-62. , 1975. Cyclic deposition of Silurian carbonates and evaporites in the Michigan Basin: Reply: AAPG Bull., v. 59. p. 538-542. Nurmi, R. D., 1974. The Lower Salina (Upper Silurian) stratigraphy in a dessicated, deep Michigan Basin: Tech. Paper, no. 14, Ontario Petrol. Inst. Ann. Conf., 25p. Paris, R. M., 1977. Developmental history of the Howell Anticline: Unpub. master's Thesis, Michigan State University, 76p. Pirtle, G. W., 1932. Michigan structural basin and it relationship to surrounding areas: Am. Assoc. Petrol. Geol. Bull., v. 16, p. 145-152. Pounder, J. A., 1962. Guelph-Lockport Formation of southwestern Ontario: Ontario Petrol. Inst., First Ann. Conf. Proc. Potter, D. L., 1975. The Lower and Middle Silurian of the Michigan Basin: Unpub. Master's Thesis, Michigan State University. Raup, O. B., 1970. Brine mixing: an additional mechanism for formation of basin evaporites: Am. Assoc. Petrol. Geol. Bull., v. 54, p. 2246-2259. Schmalz, R. F., 1969. Deep-water evaporite deposition: a genetic model: Am. Assoc. Petrol. Geol. Bull., v. 53, p. 798-823. Scruton, L. P., 1953. Deposition of evaporites: Am. Assoc. Petrol. Geol. Bull., v. 37, p. 2498-2512. Sears, S. o., and Lucia, F. J., 1979. Reef growth model for Silurian Pinnacle Reefs, northern Michigan reef trend: Geology (Boulder), v. 7, no. 6, p. 299-302. Sharma, G. D., 1966. Geology of Peter Reef, St. Clair Cocunty, Michigan: AAPG Bull., v. 50, p. 327-350. 65 Bibliography (cont'd) Shearman, D. J., 1971. Marine evaporites: the Calcium sulfate facies: A.S.P.G. Seminar, 65p. Sloss, L. L., 1969. Evaporite deposition from layered solutions: AAPG Bull., v. 53, no. 4, p. 776-789. Wilson, J. 1., 1975. Carbonate facies in geologic history: Springer-Verlag Pub., New York, 662p. APPENDIX 66 .23 BR m . m < 2 SH 3 8 62 m2 2.. NR. 26-27: 8.5. $2 8% m m < c: 2 3 a: m: cm mam 2. aka $2 $3 m m < a 9: 2 an em ~2 em com 35-27% ~33 22 RR m m < a .2: o 8 EN «.2 2: Rm 26-292 as: 3: mo: mi m < 2 SH m 8 SN 2: «8 mm... 2 ~82 R.,: ER m.< m m+< S a: 3 NF 68 .22 a: a? 2 as: .5: SS m m 94 S a: 2 6... SN 62 :6 2 238 3: 29,. m m m+< 2 c2 3 2 SN 2: e3 E-ZN-Z is: $8 83 < m m.< 3 so 2 R on. E: a: N: 3 3:: 22. a: m.< < < NN a: 2 R mm m3 3 5. 26-27% RNmN 2% an m m m+< 2 6.: w an :2 w: a a? 2 3: max 4 < < =2 2 3 s3 62 62 R... 35-27: 928 in. R? m m m 8 8 .5 on 63 62 z: 36 2.. MR: SR 39 m m m 8 2. a: R an 2: SN N8 zm-zs-m 32 23 m m m on 2. o: 6m 8m E ZN N8 2:-ch ~32 RR. 38 m.< m m 2 2. 2. G ~o~ a: s: Rm 26-203 52 SR. :3 m m m a 8 an S EN 9: 3m 8a 2 BEN 23 29 Q.- m m on mm mm 8 RN «.2 RN Rm 5.203 S: m.< m m.< 3 S SN 62 as as 3.202 8ch go >253 u~< .u an m~< u? 6 9:2 of o_ u~< o~< .5 £35 a: dam a :Esfi 9.32me 8.03055 cooaofi COS—woo; dugu >0 (5‘0 4.03 €05ng A X—9w&< 67 32 8% o 2 is o e = S S 22 362A NEE ER 5% o S a: o c e on S Sm. 2 8m: :2 c .53 o o . c S 2 N2: wN-mn-s .303 $2 2.: o 2 23 c c o B 8 32 2 SEN can 2: o 2 :2 o c o S 2. 3.: a 862 2.2 3: o 8 NS. 6 c c 8 E m2: 2 262 so: 3: D cos c o o S 8 N2: 2 as: $5 on: o «N NS 6 o o E E 2.: 2 .5: No: 22 o 2 NR 6 o o 2: 3 N2: an-mn-m SRN SR 3% c 2 a: o o e 2 S So 22.2.2 :32 2% S: o 2 is o o a on E 68 2-3-2. 32:. 5.12 B: c 2 as o o 6 N6 2 Ba wN-ms-m SEN ER 82 o 2 in o o c 3 S 82 am-mn-N 2:2 E a can a 2 ea c o o 8 E 82,. EAR-mm ~32 SS :2 c B :R o o o 8 2 ea EAR-R ~22 NS N 2.5 o 2 is o o e on R. 2: an :2 8% o 2 as o o a R 3 8: 3 «SN.»- RE SS 0 2 :3 c a o R Q 8: 3 RR 2.8 o 2 :3 o a o am so 2: an RRN :2 EN 0 3 93 o o o 2 mm 2.2 R 232 22 :8 o 2 com o o o R 3 6:: R 262 SE 2% o 2 as o o o as so as: 23-min €388 tzaou 2030.2. o~< .0 am u~< 6 9:2 m5 of u~< o~< am 535 a? .93 21 ESE 838:...“ 6202053 £02.02 83.30.. 6.269 A x5592 68 EN EN 0 2 a: c e c .3 .3 NR. 2 :EN .2: N n _ N o S. cNm c o c S cm .32 R NKN MEN c E :3 e c o 3 as $2 2 EN 3.: c N. Na 6 c c E .5 E: 2 EN EN ONON c 2 :m o a o as NN. 8: 2 EN EN n. 2 N: c c 6 Nm 3 8: R DENN EN osmN o S E: o e 6 Na R. 82 3 EN EN c 2 E o = a Na 2. 2.2 R NRNN NSN mNoN o 2 6N». o o c 3 8 «a: R NSN NcoN o 2 S: o o c Nm 3 E: an-ms-R SsNN SsN EON 0 NS 6 o 6 N6 N: R: 373-2 EmN 22 o :N a? o o a on 2. «2: N. .RN NR c 8 N: o o 6 am 5 on: m NSN 2.2 c MN m: o e o 3 B 82 e mooNN émN 2% o 2 Ne o o o 8 E R2 6 smmN $2 0 NN is o o . o Z 2 E: e .52 6:: c 2 N2 c o o R 3 £2 6 SRN SEN an: o N. in o c o .3 2 22 o RmNN oNsN chN o S oNs o a o S 2. CNS : snoNN :NmN NEN c NN NS 6 o a No 2: 68: 2 SEN SON 0 ON EN 6 o c i so 22 2 $3 enoN c 2 NS 6 o o S no :2 S cNSN 5.69 E80 2099:. oN< C ..c qu 6 9:2 0 0 UN UN .5 53.5 a: 63 N :68“: eta-5:5 » 3332:: £958— 82¢qu III II'I'-‘ 6:58 A x52uou< 69 NmnN SEN O N. Nam o c o ow 2. N2: MN meg-N nmNN RNn O N :3 o o 9 nm E Rm Mc-mn-S :33 BEN O+< O+< 69 a a o .3 NH 26 N gmNn can 3mm < < 3 can a 3 mm 2.. Ni. mam we-meH 38m. $3 amen O 3 as o a o 2. B Nam m 83 «SN 0 ON mac 0 3 o N‘- om 8m w BEN 3.3 mnNn O «N Noe o o o co we <2 2 wommN cocN mBN C NN NR a 3 0 mm m: a; 2 SemN mQN «RN O N 93 a Na 9 on ms 5mm wc-mn-o NSNN 33 SN.” O R 9.3 o 3 o R a: no: 3 BEN each 0 NN Sc 9 mm o 2. cm Rm wm-mN-mN woneN RE 33 < < NN ON: c N a cm :2 So mn-mH-NN QSN >250 33;; RR m+< m+< < 2 cm N3 2: can m; N meN 33 m+< m+< 4 ma 3 ma m2 own NNN H ESN €259 >5 shag—.— N N a H H N N . U 4 .U :m w < w 4 .U 052 w < U 4 w < O < :m 5:30 a: com u :5qu 9.38:5 3.03653 guaca- c0368.. APucoUv A X—OZUQQ< 70 6666 6.6. 6.< < 6: 66 N6: 66: 66N N66 66-2N-N: 66:6N 6666 6 6:: < 6: 66 66N 66N 6N6 6N6 6: N666N 6666 6 6.< < 6N 66 66N 66: 666 666 N 6:66N 6666 6 6+< < 6 66 66: 66: 666 N66 66 6666N 6666 6;: 6.6: < 6: 66 66: 66: 666 666 66-26-66 6666N 6:66 6666 6 6 < 6: 66: NN 66 666 N6: 6:6 6:6 :N 6N66N 6666 6 6:6 < :N N6 666 66: NN6 666 NN 6666N 6666 6 6 < 6: :6 6:6 66: NN6 N66 6N 66N6N 6:66 66:6 6.9: 6:: < 6N: 6: 66 66N 6N: 6N6 666 66-26-66 6N66N 6666 6 6 < 6: N6 66N 66: . 6N6 666 66-26-66 :N66N 6666 :66 6:: < < :: 66: NN: 66 66 66N 66: 6:6 :N :N6:6 N666 6666 6 6 6-< 6: 66N 66 66: 66: N6N N6N :66 66-26-N6 666:6 6666 6 6;: < 6: N6 N6N 66N 666 6N6 6 6666N 6666 6.< 6.< < 6 66 66N 66: 6:6 6N6 66-266 66N6N 6666 BS 6 6.6: 6.< 66 66 66 666 66: 6:6 6:6 6 666N6 6666 66N6 6 6.6: < 66 6:: 6N 66 66N N6: :NN 666 66-26-6N N66NN 6:66 < 6.6. < 6: 66: 6 6 N6N 66N N6: 6N6 66 666:6 66N6 N666 6.4: < 6N NN: 6N 66 66N 66: 666 N 6N66N N:N6 N666 6 6 < 66 66: 6N 66: 66N 66: 66N 6N6 : :666N 6:66 6N66 6.< 6.4 < 6N 66: 6: 66 66: 66: N66 NN6 66 6666N 6666 6 < < 6: 66 NN: N6: 66: :N6 66-26-N: 6666N 6666 6:66 < < :6 66: 6: 66 NN: 6:N 666 666 66-zN-6: 6666N €680: >260 2066.623: oN< .o 66 uN< 6:< 0 9:2 6:6. o:< 6N< oN< 66 6360 m: .86 6 .6566 830266.. 620365... £0.68. c0268.. Atacama A X_OZan_< 7] 6666 66:6 6:6 < NN 666 6 6: . 66 66: 66: m 666 6N 6N6N6 6666 66N6 6:6 6:6 6N 66N 6 66 66 66N 666 _ 666 66-2N-6: N666N _ 6667500 2066022.: 666N 66:6 0 6: 666 6 6 6 66 N6 :66: 66 666:N 66 6N N6N6 o 6N 666 6 6 6 :6 66 666: 66 N666N 6:6N 66:6 0 6: :66 6 6 6 66 66: 666: :6 666NN 666N o +6N: 6 6 6 66 66 6N6: 5-66-: 6N6:N N66N N666 o 6: 666 6 6 6 66 66 666 6N 6::NN 666N 6666 o NN 666 6 6 6 66 66 666 :N 6666N 6N66 6666 o 6: 6N6 6 6 6 66 66 666 6: 6666N 66:6 6666 66 NN 6N6 6 6 6 N6 N6 666 3N-6N-6: 6666N 66N6 6666 6:6 < 6N 66N 6 N6 :6 66: :6N 666 36-676: 6666N 6NNN 666N o N: N66 6 6 6 66 66 6:6: N6 6666N 6NNN NN6N o 6: 666 6 6 6 66 66 6N6: :6 6N66N 666N 666N o 6: 6:6 6 6 6 66 66 666: 6N 66 66N 666N N66N o 6: 666 6 6 6 :6 66 6N:: 6N 666NN 66 6N 666N o 6: 6:6 6 6 6 66 66 666: :N 666N 666N o 6N 666 6 6 6 66 66: 666: 6: 6666N 666N 6:66 o 6: 666 6 6 6 66 66 :6:: 6: 666NN N66N :66N o 6: 666 6 6 6 66 66 6N6: 6 6NN:N €688 52300 203.966. UN< .66 6m 6N6. G 032 u:< U:< uN< uN< 66 6360 a: .86 6 :Eaa 6:30:63 62039.3... sundow— 859.60.. 6.688 .: 620266666 72 666N 666N 66 NN :66 6 6 6 66 66 N66: 6 :66NN 6:6N 666N o 6: N66 6 6 6 66 66 N:6: 6 6666N 666N 6666 66 NN 666 6 6 6 N6 66 666: 6 6:66N 666N 66:6 0 6N 666 6 6 6 66 66 666: 36-66-N 6666N 666N 6666 o 666 6 6 6 66 66 N66: 6N :6::N 666N 6666 o 66 666 6 6 6 :6 66 6:6: 6N N666N 666N N666 o 6N 666 6 6 6 66 66 :66 6N 666:N 6666 6666 o 6N 6N6 6 6 6 6:: 66 6N6: 6: 666:N 6666 6666 o 6N 666 6 6 6 66 66 6:6: 6: 6666N 6666 6N66 o < 6N 666 6 6 66 :6 66 6:6: 6 666NN 6N66 6666 o 6N 666 6 6 6 66 :6 :66 36-6N-6 6666N 666N 66N6 o 6: 666 6 6 6 66 66 666 6:-66-6N 666:N :666 :666 o < 6N 666 6 6: 6N :6 66 666 6:6:-6 :6666 ::6N 6666 o 66N 666 6 6 6 :6 66 6N6: 6 N66:N :66N 6666 o N: 666 6 6 6 66 N6 666: 6 6N666 666N 6666 o 6: 666 6 6 6 :6 N6 666: :: 666:N 6:6N 6666 o :: 666 6 6 6 66 66 666: 6: 666NN N66N 6666 o 6N 666 6 6 6 N6 66 66:: 3N-66-:N :6N6N 666N 6666 o 6: 666 6 6 6 66 66 666: NN 666:N N66N 6:66 o N: 666 6 6 6 66 N6 666: 6N 6666N N66N 666N o 6: 666 6 6 6 :6 66 666: 66 6:6:N 6N6N 666N o 6N 666 6 6 6 66 66 2:: 66 66:6N 66.6668 >50 20663. UN< .u 66: wN< .0 9:2 m:< 0:< 6N< uN< 66 5360 E6 .86 6 66:66 23826 66.666933 5868: 8:684 APucoUv A X_OZUQQ< 73 666N 666N o 6: 666 6 6 6 66 66 :N6: 6: 666NN N66N N66: 0 6: 6:6 6 6 6 66 66 666: 6N :66NN 666N N86 0 6 666 6 6 6 66 66 66:: 6N 6:6N 666N o 6N 666 6 6 6 66 N6: ::6: 3666-6: NN66N 666N o 6 6 6 66 N6 666: 6N 666N 6666 o 6N 666 6 6 6 66 66 666 26.66-66 :66NN 666N 6666 o NN6 6 6 6 66 66 6N6: 66 6666 o :N :N6 N66: 36-66-66 6:6N 6666 66 NN 666 6 6 6 66 66 N66: 5-66-6: 6:66N 666N N6:6 o 6: 666 6 6 6 66 N6 666 3:-66-6N 66NNN 666N 66:6 0 6: 666 6 6 6 66 66 666: 36-66-66 6666N 6N6N 66:6 0 :N 666 6 6 6 66 66 666 36-666: 66:NN 6N:6 N666 6+< < 6N 66N 6 :6 66 66 6N: 666 3N-6:-N6 6666N 6N6N 6666 o 6N 666 6 NN 6 N6 66 :66: uN-66-6N 6666N :66N N666 < 66 6:6 6 6: 6 66 66 N66: 36-6N-6N 6:66N N::6 6666 o < < NN 666 6 6 6: 66: N6 666 3N-6N-6: :666N :666 6666 o 6N 666 6 6 6 66 66 6N6 6N N66:N 6N66 6666 o 6N 666 6 6 6 66 66 666 6: 6N666 :666 :666 o < 6N 666 6 6: 6N :6 66 666 6:6:-6 :6666 66N6 6+< < 66 66 66: 66N 666 N 666:6 66:6 6666 616 < 6N 66N 6 66 66 N:: 6N: 6N6: 66 6666N 66:6 6+< < +66: 6 66 66 6:: N6: 666: 66 6::66 66.688 >260 209.966. 0N4 6 66 uN< u .0 9:2 u:< U:< wN< UN< 66 5360 E6 .86 6 :6an 330363 6286053 5006.03 c0308.. GLCOUV A X_OZUQQ< 74 66:6 6N66 < < 66N 6 66 66 6:: 6N: 6N 66666 6NN6 6666 6;: < 66N 6 66 66 66: 66: 666 6: 66666 6:N6 6666 636 < 6N 66N 6 66 66 66: N6N 666 :: 66N6N 6NN6 6N66 636 < 6: N6N 6 66 66 N6: 66N 666 6: 6:6NN 66N6 :666 6+< < < 6N 66N 6 :6 :6 66: 66N 666 6 :666N 6666 66.6 < < 66 66 66 :6: 66N N66 36.6: 66666 6:N6 6:66 .6 < 6: 66N 6 66 N6 N6: 66 666 3N6:-6N 6:666 6666 6666 < < 6N 666 6 6: 66 66 66: N66 N: :66N6 6666 :666 < < 6N 666 6 6: 66 66 66: 6N6 :: 666N6 N666 6666 < < 666 6 6: 66 66: 6:: 666 6 :666N 6666 6666 < < 6N 666 6 6: 66 66 6:: :66 3:-6:-N 6666N >260 206x05. 6N6N 666N o 6N 6:6 6 6 6 66 66 666 6N 6666N 666N 6N6N o :N 666 6 6 6 66: 66 6N6 36-66-6N N6N6N 66:N 666N o 6N 666 6 6 6 N6 66 666 6: 6666N 66NN 6:6N o 6: 666 6 6 6 66 66 N66 3666-6: 6666N N6NN 666N 66 NN :66 6 6 6 N6 66 :66 6N 6666: N6NN 666N o 6: 6:6 6 6 6 :6 :6 N66 3666-6 N666N 666N 666N o NN 666 6 6 6 66: 66 666 366N-6N 6666N 6: 6N 66:6 0 NN 666 6 6 6 :6 66 666 36-6N-6: 6666N 66.66606 >260 2:61.20 0N< .0 66 uN< u .0 0662 u:< 0:< mN< 0N< 66 6.360 E6 .86 6 66:66 0630365 620305... £02.06— 663000.. APEOUV .n X—OZU&< 75 666N < < +66 6 6: 66 66 N6: :66 66 N6666 666N 6666 < .6 N66 6 6: 66 66 66: 666 66 66666 666N < 6. +66 6 6N 66 66 6:: 666 6N 666:6 666N 6. < +66 6 6N 66 66 66 666 6N 666N6 666N < < +66: 6 6N 66 66 66: 666 NN 6N: :6 666N < .6 +66 6 66 6N 66: ::: 666 6: 6:666 6666 < .6 +66: 6 6: 66 66: 6:: 666 6: 66666 666N < < +66 6 6N 66 N6 66: 6.66 6: N6666 666N < .6 +66 6 6: 66 66: 66: 666 6 66666 666N < .6 +66: 6 6N 66 N:: 6:: 666 6.6.6:-6 66666 666N N666 q < < 6N 66N 6 66 N6 N6: 6:: 666 66 66666 666N 6666 6. < 6: 666 6 66 6 66 N6 :66 66 666NN 666N < .6 +66: 6 6N 66 66 66: N66 66 666N6 :66N 6666 < < 666 6 6N 66 66 66 N66 N6 66666 666: N666 < 4 N66 6 6N 66 66 ::: 666 :6 66666 666N6 < 6. +66: 6 6N 66 66 66: 666 66 666:6 666N 6666 < < 66N 6 N6 66 66: 6:: 666 6N 6666N 6N6N < .6 +66: 6 :N 66 N6: 66 666 6N 66NN6 666N < < +66: 6 :N 66 66: N6: N66 6N 66:66 666N < < +66N 6 6N 66 66 66: 666 :N N66N6 :66N < 4 +66 6 6N 66 66 66: 666 6: 666:6 666N < < +66: 6 66 66 N6: 6N: 666 6: 66666 .6680. >260 261.20 0N< .0 66 6N< u .0 052. 6:4 0:... UN... 0N< 66 6360 E6 .86 6 26:66 238.56 66.66665... 5668. 8:68.. €380. .H X—OZUQQ< 76 666N < < .6 +66 6 :6 66 66: 6N: 666 6: :66:6 666: < < +66: 6 6: 66 66 66 666 6: 666:6 666N < .6 +66: 6 6N 66 66 66 N66 6: 666:6 6:66 < < +66: 6 66 66 66: :6: 666 6: 6N6N6 N666 < .6 +66 6 66 66 66: 66: :66 :: N66:6 6666 < < +66N 6 6: 66 66 66: 666 6: N666N 6666 < < +66N 6 6N 66 66 66 666 6 N666N :66N < .6 +666 6 NN N6 66 66 666 6 6N66N :666 < < 6. +66 6 6: 6N 66N 6:: N66 6 66666 66:6 6N66 < < 6N :6: 6 66 6N 6:N 6:: NN6 6 666NN N::6 6666 < < 6: 6:N 6 66 6N ::N 6:: 666 6 6666N 66:6 6. < +66: 6 66 66 6N: 66: 666 6 6:666 N6:6 < < < +66 6 66 66 N6N N:: 666 36.6: 6666N 666N < .6 +66: 6 6N N6 66 66: :66 6N 66:66 :66N < 6. +66 6 66 66 N6: 6:: 666 26673 66666 :66N < .6 +66: 6 6 6N 66: 66: 666 6N 666N6 666N 66N6 < < :6N :: 66 :N 6:N 66: 666 6N 66666 666N < 6. +8 6: 66 :N 66N N:: 666 NN 666:6 N66N < 6. +66: 6 66 66 66N 6N: 666 6: 66666 :66N N666 < < 6N 66: 6 66 6: N:N 66: 666 N: 666NN 666N < .6 +66: 6 NN 66 N6 6N: 666 66 66:66 N66N < .6 +66: 6 6N 66 66 66: 666 66 66N66 5:80. >260 156.20 0N< .0 66. uN< 6:6. .0 032 6:6. 0:< 6N6. 0N< :6. 5360 E6 .86 6 .6an 230:..3 60.0305... 6.0.66.8— 8:08.. GLSUV .m X_OZU&< 77 666N < .6 +66: 6 NN 66 66: 66 :66 6N 6666N 666N N6N6 < < 6N 666 6 6N 66 66 66 N66 6N 66:6N 666N < 6. +66: 6 6N 66 6:: 6:: 6:6: 6.6-6:-6N 6:6:6 6666 :666 o < N: 66: 6 66 6N 6:N 66: 666 6 6666N N66N 6666 o < 6: 66N 6 N6 6N 6NN 66 666 2.6-6:-6 666:6 6:NN 666N o 6: 666 6 6 6 N6 66: 666 :6 6666N 66N: N:6: n. 6: 666 6 6 6 66 66: 6:6: 6N 6666N N:6N 666N o 6: 666 6 6 6 66 66 <2 36-66-: 66:6N N:66 6666 < < < 6: 66N 6: 6 6N N6: 66: :66 6N :66:6 666N < < 6N 66 66: 66 666 6N 6N:66 6N:6 < < 66 66: 6:: 666 6 6666N 6N:6 6N66 < < 6+< 66: 6: 66 6N 66: 66: 666 6: 666N6 NN:6 < < < 66 N: 6N 6N 66: 6:: 666 6.6.6:-6 6666N 66NN 666N o 6N 666 6 6 6 66 66 666 6.6.66-6 N666N 66:N 666N o 6: 666 6 6 6 66 66: 666 66 :N66N 66:: N66N o 6: 6:6 6 6 6 66 66 6N6 6 66 66N 66NN 666N 6. 6N 666 6 6 6 66 66 :66 6.6-66-6 666NN N:6N :66N o 6N 666 6 6 6 66 66 6:6: 36.6666 6666N 66:N 666N o NN 666 6 6 6 66 66 666 :N 6666N 6:NN 666N o 6N 666 6 6 6 66 66: N66 6: :6666 6:NN 666N o 6N 666 6 6 6 :6 66 666: 6: 6666N :6NN 666N 0 6N 666 6 6 6 :6 66 666 6.6.66-6: 6666N 66.680. 5:60 2.61.20 0N< .0 66 uN< 6:... .0 052 6:... 0:... 6N< 0N< 66. £6.60 at. .86 6 ::an 8302...... 66.0505: 6.00606— 6630004 9.66.00. A X_DZU&Q< 78 666N 666N o 6: 666 6 6 6 66 :6: <2 :6 :6:6N 666N 666N o 6: 666 6 6 6 66 6:: 6:6: 6N 666:6 666N 666N 6. 6: 666 6 6 6 66 N6: 6N6: NN 666N 666N o 6: 666 6 6 6 66 66 666: 6N 6:66N 666N 6:6N o 6N 666 6 6 6 66 66 666 6: 666NN 666N 6:66 o 6N 666 6 6 6 66 66 6:6: 6 66N6N NN6N 6666 o 6N 666 6 6 6 66 66 666: : 666N 6666 o 6N 666 6 6 6 66 66 666: : 66N6N N66N 6666 66 NN 666 6 6 6 66 66 666: : 666N 6666 o 6N N66 6 6 6 66 66 666: : 666N 6666 66 NN 666 6 6 6 :6 :6 666: : 6666N 6:6N 6666 o 6N :66 6 6 6 N6 66 666: : 6:6N 6666 o 6N 666 6 6 6 66 66 N66: 36-66-: 666N 666N o :N 6:6 6 6 6 :6 66 666 6: 6666N 666N 666N o 6N N:6 6 6 6 66 66 :66 6.6-66-6 :666N 666N NN6N o 6: 666 ,6 6 6 66 66 :66 66 N66N6 666N 6:6N 6. 6: 666 6 6 6 66 66 N66 36-66-66 6666N 666N 66N6 o 6: 6:6 6 6 6 66 66 :66 6 :6.NN 666N 6:66 o 6: 666 6 6 6 66 66 666: 66 66:6N 6666 66:6 0 6: 6:6 6 6 6 66 66 666: 6N 6666N N66N 66N6 o 6N N66 6 6 6 N6 N6 666 N: 666:N 666N 66:6 0 NN 666 6 6 6 66 N6 666: :: 6666N 6.680. >260 7561-20 0N< .0 66 uN< .0 052 u:< 0:< mN< 0N 66. 5366. E6 .86 6 6.6.6.. 83626 8.66.65... 6868. 8:68.. 93:00. A X_OZUQQ< 79 666N :6:6 0 6: :66 6 6 6 :6 66 666 6 :666N N66N 66:6 0 6N 666 6 6 6 66 66 666 6: 6:6N 66:6 0 NN 666 6 .6 6 :6 66 666 6: 66NNN N:6N 66:6 6. 6N 666 6 6 6 66 66 666 6: :6:6 :N N66 6.6.66-6: 6:6N 66:6 6. 6N 666 6 6 6 66 66 N66: 2.6-66-6: NN6NN NN6N 66:6 0 :N 666 6 6 6 66 66 6N6: 6: 666NN N66N 66N6 o 6: 666 6 6 6 N6 N6 666: 6: :66N 66N6 o :N 666 6 6 6 66 66 6N6: 6: 666N 66:6 0 6N 666 6 6 6 N6 66 6:6: 6: 666N N:N6. o 6: 666 6 6 6 66 66 666: 6: 666N 6NN6 o 6N N66 6 6 6 66 66 :66: 6: 6N6NN 666N 6:N6 66 NN 666 6 6 6 66 66 N66: 6: 6:6N 66:6 0 NN 666 6 6 6 66 66 666: 6N 666N 66:6 6. 6N 666 6 6 6 66 66 N66: NN 6666N 6666 66:6 6. :N 666 6 6 6 6:: 66 666 6: 6:6N 66N6 o 6: 666 6 6 6 66 66 666 6 6:6N 6:N6 o 6: 6N6 6 6 6 66 66 666 6 666N NNN6 o 6N NN6 6 6 6 66 66 666 6 6N6N 6NN6 o 6N 6N6 6 6 6 66 66 666 6 666N 6NN6 o 6N 666 6 6 6 66 66: :66 6 666N 6666 o 6N 666 6 6 6 66 N6 6N6: 66 6666N 66.6806 >260 g3 0N< .0 :6 0N< u .0 052 u:< 0:< 0N< 0N< :6. 6360 at .86 6 6.5666. 9.302% 6203053 £006.06— 653000.. 6.6.6660. .: 50206.6( 80 666N :666 o 6N :66 6 6 6 66 :6 6N6: 66 6666N 6:6N 6666 o NN 666 6 6 6 66 66 N66: 66 666NN 6:6N N666 o 6N N66 6 6 6 66 N6 666: 66 N666N 6N6N :6:6 0 6N 666 6 6 6 66 66 666: 66 6666N 666N 66:6 0 6N :66 6 6: 6 6N 66 :N6: 6N 6:6N 66:6 0 :N 666 6 6: 6 66 66 666: 6N 666:N 666N :6:6 6. 6N 666 6 6: 6 66 66 666 6: 666NN 666N 6N:6 o 6N NN6 6 6 6 6:: 66 N66 6: 666N 66:6 6. 6N 666 6 6 6 66: N6 666 2.6.66-6: N66:N 6N6N . 66:6 0 6: 666 6 6 6 66 66 666 6: 666N N:N6 o 6N 6:6 6 6 6 66 66 666 6 666N 66N6 o 6N 666 6 6 6 66 66 666 6 666:N 666N :6:6 6. 6: 666 6 . N: 6 66 66 ::6: 2.6-66-2 N666 6666 < < 6N 6:6 6 N: 66 66: 6N: 666 6: N66:N NN66 6666 < < 6N 6N6 6 6: 66 66: NN: 666 2.6.6:-6: 6666N N:6N < < < 6: 6: 66 6:N 6:: 666 :N :N::6 666N < < < 6 6N 66 66: 6:: 666 :N 6666N 666N < < 6 6 66 66 66 N66 6N 6666N 666N < < 6 6N 66 6N: 66: 666 6N 66666 6666 66N6 < < NN 66N 6 66 6: 66N N:: 6N6 2.6.6:-6N 6N66N 666N 6N6N o 6N 6:6 6 6 6 66 66: N66 6.6-66-6: N66NN 666: 666N 6N . 666 2.6.66-6 :666: 66680. C7500 2:61.20 06< .0 66 mN< u .0 032 0:6. 0:< uN< 0N< 66 5366. E6 .86 6 6.6.666. 0.63023 8.03053 £06606. 83000.. 93:38 A X-OZUQQ< 81 N6NN 666N 6. 6N 666 6 6 6 66 66 666 2.6-66-6: 6666N N66N 666N 6. 66 :66 6 6 6 66 66 6N6: NN :666N 666N 666N 6. NN 666 6 6 6 66 66 N:6: N: 666NN .66N 6666 6. 6N 666 6 6 6 66 66 666: : 666NN 666N NN66 o 6: :66 6 6 6 66 66 666: 36-66:. 6::6N 666N 66N6 o 6: 666 6 6 6 66 66 :N6: 6: 666N N6:6 o 6N 6N6 6 6 6 66 66 666 6: 6. 6N 66N6 6. 6: :66 6 6 6 66 66 666 6 666N :NN6 o :N :N6 6 6 6 66 66 666 6 666N 66:6 6. NN 666 6 6 6 66 66 N66: 6N 6666N 666N 66:6 6. NN 6N6 6 6 6 66 66 N66: 6N 666N 6666 6. 6N 666 6 6 6 66 66 666: NN 6666 66:6 6. :N N66 6 6 6 66 66 6:6: 6: 6:66N .66N 66:6 6. NN 666 6 6: 6 66 :6 6N6: 2.6-66-6: 666NN 666N 6:N6 < 6 N66 6 6N 66 66 6:: 666 2.6-6N-6: 66666 6.: 6N N6N6 < < 666 6 6: 66 66 N:: :66 36-6N-N :6666 666N 66N6 6. 6: N66 6 6 6 N6 66 666 66 6666N 666N 66N6 6. 6: N66 6 6 6 N6 66 666 6N 666NN 666N :6N6 6. < 6: 666 6 6N 6 66 66 666 6N N666N 666N 6N66 < 6: 666 6 6 6 N6 66 666 6: ::N6N 666N 6666 < < 6N 6NN 6: N6 66 66: 66 666: N: 6N6N6 666N 6666 < < 6: 66N 6 66 66 6N: 66: N66 6 6N66N 66.6660. >950“. 7:86.30 0N< .0 66. 6N< .0 032 6:6 0:... 6N< 0N< =6 56.66. m? .86 6 6656 6:30:63 60.03053 6.006606— 6.2.3001. .6680. .: x.6.zu.n.6.< 82 NmON eOnn O OH OOn O AN O am No 0OO~ BcnmNuhN OOON annn O OH ONQ O 6N O No OO Ohm : nOONN NmON O Rm 0 mm oOn O ON O mm NO new w O~ON Tim 0 MN. 960 O O O NO OO who On ~OOnN NONN ::Nm 0 ON One O O O NO 0O Nha NN meNN cmON {Omn 0 ON Ohm O O O Nu OO cam a. mncNN NNON emNn 0 ON can O O O OO wO nna MA nOmnN OOON Ownn O Na OOn O O O NO OO New NH OchnN mmON ONMM O OH OOM O QN O Om nO MNo Na OOOMN nnON O33 O < ON nON O nm Na Na OO GOO gnumNn~ MNNNN NOON NmNn O Na mom O On O mm mO new mm NmanN NNNN mwNm O 6: ON Own O on n :3 mO mum mm NMONN nNON anm O OH Ann O Na O mm NO who Mm OQNNN OOON NOmn < 6. OH wen O an OH 63 0O MOO ~N thN Ownn D < mm OO: O ON 6 ma NO Ohm ON omOmN QOON Hmnn < NH Nhn O On O mm NO GOO OON mchN OOmN 6.0mm O 6. NH OOM O :N O on .NO mOm m~ ONON nann O < < m~ Omn O :N Nu ma wO OOm OH OOON ennm OH «On O MN O OO mOO ma unhnN ccON Ommn < cm wOn O ON O O0 ON mnm goumNuOH NmmNN 2 ON hmnn < < < NH man O Na MA 00 MO Nnm BouwNnh mmmMN ooON Ommm 66.34 < < mmq : me HN m: an cmO Na ~OOQN ADOSUV >5 :5..an 0N< .0 :6. 6N< 6:.6 . .0 c<.z 6.:< 0:< 6N... 0N< :6. 8366. E6 .666 6 66:66 230:...5 62039:... £069.6— c0268.. 66.260. .: 66.6.2092 83 666N 66N6 6:6 6. < 6N 66: 6: 66 6N 66: 66: 666 36-676 6:N6N 666N 66N6 < < 6N 666 6 N: 66 66 66 N66 6N 66:6N 666N < < 6: 66 N6: 66 666 6N 66666 666N < < < 6 6N 66 66: N:: 666 :N 66666 666N < < 6: 66 66: 66 666 36-6:-:N :6666 666N 6666 < < 6N :66 6 6: 66 66: 6:: 666 N6 66666 666N 6N66 < < 666 6 6: N6 66 66: 666 6N 66666 N66N < < :: :6 66 N6: ::6 6N ::666 666N < < 6: 66 N6 66: 666 6: 66666 666N 6666 < < < 66N 6 66 66 N6: N:: 666 6 N6666 N66N 6666 < < 666 6 6: 66 66 66: 666 6.6.6:-6 66666 666N 6666 < < 666 6 6N N6 66 N:: N66 6N 66666 666N 6666 < < 6N 66N 6 66 N6 66: 66: 666 6N 6N66N 666N 6:66 < < NN 66N 6 66 :6 66: ::: 666 6N 666NN 666N 6666 < < 666 6 66 66 66: 66: 66 NN 6666N 6N66 6666 < < 6: 666 6 66 N6 66: 6:: 666 6: 6666N 6666 6666 < < :N :6N 6 66 NN N6: 6:: 666 N: 666NN 6666 < < N6 N6 66: :66 N: 6666N 66:6 6N66 < < < 6N 66: 6 66 6N 66N 6N: NN6 6 666NN 6NN6 6666 < < < 6N 66: 6 66 6N 6NN 6:: :66 : 6:66N 66.6 < < < 6 66 6N 66N 66: N66 36-676 6NN66 666N N666 < < N: 66N 6 N6 66 66: 66: 666 66 6N66N 66.680. .5250 759.960 0N< .0 :6 6N< 6: m0 0<.z m:< 0:< 0N... 0N6. :6. 5366. E6 .86 ... 6.6.66. 23025 620305... 6.06006— 8368.. Cuzco“: .m van—2&6; 84 666N 6666 < < < 6: 66N 6 66 :6 66: 6:: 666 N6 6666 < < 66 66: ::: 666 36-676: 6666N >250 2301.30 :666 6666 6.6. < NN 666 6 6: :6 66: NNN 666 6.72:6: 6666N 6666 6:6 < +66N 6 N6 66 :6: NN6 666 66 6:66N 6666 6+< 6:6 6+4 6: 66: 66: 66N :66 :66 6 66: 6N 6666 6.... .6 N6 66 :6: 66N 666 6N :666N 6666 6666 6+< < < 6N N6N 6 NN 66 66: 666 666 6N 6::6N 6666 626 < +66N 6 6: 66 66: :6N 666 6N 66666 N6N6 66.6 6+< < NN 666 6 66 66 6N: N6N 666 3N-zN-:6 6666N 6666 626 .6 +66: 6 NN 66 6N: 66N 666 66 666N6 6666 6.4 < +66: 6 6N 66 6N: N6N 666 :6 6N66N 6666 636 < +66: 6 6N 66 6N: 6:6 N66 N6 666N6 66N6 6666 6+6. < 6N 6N6 6 6N N6 6:: 66N 666 66 666N6 :666 6+4 < +66: 6 NN 66 :N: 66N 666 6N 6N666 6:66 6:66 636 < 6 666 6 NN 66 6N: 66N 666 6N 66N66 6.66 6+6. 6. 66 66: 666 666 6N-2N-6N 66N66 6666 6:: < +66: 6 NN 66 6:: 66N 666 6 666N6 :666 N:66 6+6. 4 6: 666 6 6N 66 66: 6N6 666 6 6:66N 66 66 :666 6+< < 66 6:6 6 66 66 N:: 66N 666 6 6666N 6666 6N66 636 < 6: 666 6 6N 66 6:: 66N :66 6 6666N 5.660. 66,500 2512 0N< .0 :6. 0N< 0:6. .0 9:2 0:... 0:< 0N< 0N< :6 E366. E6 .86 6 6.5666. 0.56025 6206605... 6.066.06— 65:600.. ADLCOUV A X—OZwQQ< 85 :666 6:6 < +66: 6 6: 66 6:: 666 666 6N-2:-6 6666N 6:66 636 < 6: 6N 66 66: N6N 666 :6 6.666 6N66 6+... .6 66 66: 66N N66: N6 666:6 < +66N 6 6: 66 666 NN :666N 6666 6::: < +66N 6 N: N6 66: N6N 6:6 .2276: 6:666 6666 6666 6+6. 6. 66N 6 6: 66 N:: N6N N66 6: 6666N 6:66 626 < +66N 6 6: 66 6:: :6N 666 :: 6666N 6666 66:6 62 < 6.6 6 6: :6 N:: 6NN :66 26.276 :666N 6666 62 < +66: 6 :N N6 NN: N66 666 0:.2N-6N 6666 < < .6 66: NN 66 N6 66: :N: 6N6 uN.z6-:N 6:66N 66N6 :666 6+... 6.6. < :: N6: 6: :6 66: 66: N6: :66 0N.z6-6N 66:6N 6666 6666 6:: < N: 6N6 6 N6 6: :6: 66: N66 6 N6N6N 6666 6+4 .6 66: 6 NN 66 66: N:N 666 6 6666N 6666 6N66 < < 6: 666 6 66 66 66 6N6: 372:6 6666N 6N66 636 < 66N . 6 66 N6 6:: 66N 666 N 666:6 :666 :666 < < < N: 66: 66 66: 66 :6: 66: 666: 3N2:-: 6666N 6666 6+< < 66 66: 666 666 :N . 666:6 6666 6;. < +66: 6 NN 66 N6: 66N 666 6: 6666N :666 63 < +66: 6 6N 66 6N: 66N 666 6 6666N 66:6 6666 6.... < < 6: 6:6 6: 6 66 6:N 66N 666 0N.zN.6 66:66 66N6 6666 6 < < 6: 66: 6N 66 :6 66N N66 N66 0:26-66 66N6N 6666 636 .6 +66 6 6: 66 66: :6: N66 N6 6N66N 66.6660. >260 33.9. 0N< .0 =6. 0N... 6:4 .0 04.2 u:< 0:< 0N< 0N< :6. 5366. E6 .86 6 .6an 2303.56,. 60.03053 6.066.8— 53600.. APucoUv A X—Q‘E 86 6:66 6666 6:6 .6 < 6: 6:N 66 66 66 66: 6:6 666 6N 6666N N666 6+< .6 +666 6 6: 66 ::: 66N 6:6 6 :6666 6666 6;. .6 N6: 6NN N:6 6:6 6 6666N 6666 6:66 6+... < 66: 6 :6: 66 6NN 666 666 6: 6666N 6N66 6.6. .6 +666 6 6N 66 66: 66N 6:6 6: 6666N 6666 6:6 .6 +66N 6 6: 66 NN: 6NN 6:6 6: 6666N N666 6+< < +66N 6 6: 66 6N: 66N 666 3:-2N-6: 6666N 6:66 6:6 .6 6 :: 66 6:: 6NN 666 6: 666N6 6666 626 < 6 N: 66 6N: 66N 666 3N-2:-6: 6666N N666 6666 6+< < 66 666 6 6: 66 66 66: 666 372.66 N666N 6666 6666 6+< < 6 N6 6 66: 66: N66 3:276 N6N6N 6666 66:6 6.... < 66 666 6 N: 66 66: 66: 666 :6 6666N 6666 6N66 636 < 666 6 6N 66 66: 66N 666 6: 6:66N 66N6 6666 616 .6 N6 666 6 6N 66 6N: 66N N66 6N-2:-6: 666NN 6666 < < +666 6 6N 6 66 66 666 3:-2:-:: 6:66N 6:66 6666 6+6. .6 < :6: 6 66 NNN 6:: 66 666 6N-26-6: 6666N N666 6N66 6;. 6 N66 6 6: 66 6N: 666 6N6 6: 6666N 6666 6:6 6 66 66: 6:6 666 N: 6666N 6666 N666 6 < 6N 6:N 66N 666 N6 66666 6N66 6666 6+< < < 66: 6: 66: 66 66: 6N6 666 6:-2N-6N N6:66 6666 66:6 .6 < 6N 666 6 6: :6 66 66: :66 66 6666N :666 N66 6 < 666 6 6: 66 66: 666 6.72:6 N666N 66.260. £360 25,62. 0N< .0 6:. 0N< u .0 0.6.2 6:... 0:< 0N< 0N< 66 $6.60 at .86 6 .6an 9.30:...m 620505... guano»— 6.2.000.— 3.ucoUv A X_QLUQQ< 87 6N66 6666 6;... < 66: 6 66: 66 66N 66N 6N6 :N 6666N 6666 6N66 6+< < 66: 6: 66 66 :6N N6N 666 6: 6:66 6666 63. .6 6:6 6 6: 66 66: N6N 666 66 6666N 6666 6:66 636 < 66 666 6 N: 66 6N: :6N 6N6 6N <-:666N 66 66 N666 6+6. .6. 66 666 6 6: N6 6:: 6NN N66 6N 66N6N 6666 6666 6+< < 66 6:6 6 6: 66 6N: 6:N 666 3:-2N6N 6666N N666 6666 6+4 6+< 6:: 6N ::: 6N: 6:N 6:6 6:6 :: N666N 6666 NN66 6 6+< 66 NN: 6N 66 N6: 6:N 6N6 6:6 6: 6:66N 6666 < 6 N6 6:N 666 666 66 6666N 6666 6:N6 6+< < :6 66: 6: 6N: 66 N:N N6N 666 >.N-2N-66 6N66N 6N66 6N66 6:6 .6 6N 666 6 6: 66 66: 66N 666 6N :666N 6666 6666 6:6 6. 66 66: 6 66 66 66: 66N :66 :N 6666N 6666 6+< < :: 66 66: 6NN 6:6 6N 66666 6N66 6+6. 6. N: 66 6:: 66N 6N6 3N-2:-6: 6N6N6 :666 6:6 .6 N: 66 6:: 66N 6N6 6: 666:6 6666 N6:6 6:6 .6 N66 6 6: 66 66 66N 666 6: 6666N N666 636 < 66 N6 66: 66N 666 6: 6666N 6666 66:6 6:6 .6 6N 666 6 6: 66 6:: 66N 666 6. 6666N 6666 66:6 6::: .6 N66 6 6N 66 66: 66N 666 6 6666N 6666 6:6 < N: 66 6:: 66N 666 6: :N66N 6:66 N666 6+6. .6 N66 6 N: N6 N:: 6NN 666 3N-2:-6 6N66N 6666 6666 6+< < 66 666 6 6: 66 66: 66: 666 32:66 6:66N >6z60 25.6.2. 0N< .0 :6. UN... 6. .0 0.6.2 0:< 0:< 6N< 0N< :6 6366. E6 .666 6 .6566 2302.5 62039:... £066.06: 662000.. ApacoUV A X_OZUQQ< 88 66N6 < < < 6 66 N: 66: 66: 6:6 36-2766 6666N 6:66 6666 6:6 < 6: N66 6 6: 66 6N: 66: 6N6 N 666N6 6:66 6666 6+< < 6;: 66: 6N 66 6N N:N 66: 666 36.276 666:6 :666 < 6;: 6 6N 66N 66 666 :6 666N6 N666 6:66 62 < < 66: NN N6 66 6NN 66: 666 66 6N6N6 :666 6666 63 < 6:6 6 6N 66 :6: N6: 6:6 66 :6:66 6666 626 < 6:6 +66: N6 66 66 66N 66N 666 36-2N-66 66666 6666 6666 < < < :N 66: 6: 66 6: 66: 6:: 666 N: 6666N 6666 6666 < < 6;: 6N 66: 6: N6 NN 66: 66 666 6: 6666N 66N6 < < 626 +66: 6: 66 6N 666 66: 666 66 66666 66N6 6:66 .6 < 636 NN 66: 6N 66 6N 66N 6:: 6:6 36-2766 6666N N666 66:6 6;: < 6N 6N6 6 6: N6 6N: 66N 6N6 : 666N6 6666 6+< < +666 6 6: 66 6N: N6N 666 6 66666 N666 6:66 6+< < 666 6 6: 66 66: 66N N:6 36.276 :6666 6666 636 .6 +66: 6 6: 66 6:: 66N 6N6 6: 6:66N 6666 6:6 :6 +66N 6 6: 66 N6: 66N 6N6 :: 6N66N 6666 6:6 4 +66: 6 N: 66 6N: 66N 6:6 N: 666N6 6666 6.6. :6 +66: 6 :: 66 6N: N6N 666 6: 66N6N 6666 636 < +66: 6 6: 66 6N: N6N 666 6: 6::66 6:66 6+< 6. +66N 6 6: 66 6:: 66N NN6 6: 666N6 66.6806 >958 295 oN< .U :6 uN< 6:< .u 052 6:6: o:< uN< uN< :6 8360 E6 .86 6 =an 230356.. 620069.21. guano... 66:08.. GLSUV A X_OZm—n_&< 89 6N66 6+< < +66N 6 6: 66 6:: 66N :66 6N :666N 6666 6+6: 6: < +66: 6 N6 66 66: 66N 666 36.276N 666:6 6N66 6+< 6+< < +66N 6N 66 66 66N 666 6N6 . :N 666N6 6666 636 .6 +666 6 6: 66 6N: 66N 6:6 6N N:66 6+4: :6 +66N 6: 6: 66 66: 66N 666 6N 6666 6+< < +666 6 N: 66 6:: 66N 6:6 N6 666N6 6666 6+< < 6+< 6N N6 66 NNN 6:6 666 66 66666 N:66 636 < +666 6 N: 66 6N: 66N 666 66 6666N 6666 6:6 < < 6: 66 N6 N6N 666 666 36-2N-6N 6:666 N666 6666 6+< 6 6+< 6: 66: 6: 66 66N N6: 6NN 6N6 6N 6:N66 6666 6:66 6:6 6 6:6 NN 6N: 6: 66 66N 66: 6:N 666 36-2N-6 6:6NN 6666 N666 6+< 6 6+< 6N 6N: 6N :6 66N 66: 66N 6N6 6: N66NN 6666 N666 < 6 6:6 NN 66: 6N N6 6NN N6: 66 6:6 NN 6N66 N666 6+< 6 < :6: 6: 66 6:N :6: 66 6N6 36-2N-NN 6:66N 6: 66 66N6 6:6 :6 6+< N6: 6: 66 6N 66N 66: 6:6 36-2N-6N 6666N N666 N666 6+< 6 < 6N 66: 6 N6 6:N 66: 6N: 666 6: :66NN 66N6 6666 < < < 6N N6: 6 66 NN 66: 66: N66 6N N666N 6666 < < 6N 66: 6 66 6N 666 6N 6666N 6666 66 N66 6: :666N 6NN6 6666 6:6. 6 < 6N 66: 6: 66 N:N 66: N6: 666 36-2:-N 66:6 N666 < < < NN 66: 6: 66 NN 66: 66 666 36.2766 66:6 N666 < 6 < 6N 66: 6: 66 66: 66: 66 :66 6: 66.688 >260 295 uN< .0 =6 6N:6 6:6: .0 052 u:< U:< wN< UN< 66 8360 E6 .86 6 66:66 232:3. 63039:... £86.06. 53.68.. GzcoUv .H X—nzuuax‘ 90 66N6 :666 < < < 6N 66: 6: 66 _ NN 66: 66: 6N6 36-Z:-6N 66N6N 6666 6666 < 636 6 66: 6: 66: 6 66N 66N ::6 6: 6666N 6666 66N6 6+< < < 66 N6: 6 66 6N N6N 6:N 666. 36-2N-6N 6::6N N666 66N6 6 6 .6 N6 66: 6: N:: N: :6: 66: 666 36-2N-6: N666N 6666 N666 6 6 6 N6 66 66: 66 NN6 :6: 66N 666 36-266: 66:6N 6N66 6+< 6+< < 66 66 66: 6NN :6N 666 36-26-N6 6666N N666 N666 6+< 6 6 :6 66: N6 66 :6N 66: 66N 666 36-26 -6: N6666 6:66 < 6. N6 6:N 66: 666 6 :6NN6 6N66 < < 66 66: 66 N66 6 666:6 6666 6:6 .6 +666 6 6: 66 6NN 66N 666 36-2N-6: 6NN6N :666 N666 6+< < 66 666 6 6: 66 6N: 66N 666 36-2N-66 6666N 6666 6666 < < :6 N6: 6: N6 66 66N 66: 666 6N N6N66 6NN6 6666 < < < 6: 66: 6: 66 6N 66: 66: 6:6 6N :6N66 . 6666 < < :: N6 66 66 666 66 6666N 66N6 6666 < < < 6N 66: 6 66 NN :6: 66 666 66 N6666 66:6 N666 6:6 6 < 66 66: N: 66 66: 66: 6:: 666 36-276: 66:6N 6666 N666 < < < 6: N6: 6: N6 6N 66: 6:: 666 6: 6666N 6666 < < 6: N6 NN 6NN 66 6:6 36-2:6 6666N 6666 6666 6+< < 666 6 6: 66 6:: 6NN 6N6 NN 6N6:6 N666, 6666 6:6 - < 66 N6N 6 66 66 66: 6:6 6:6 6 6666N 6666 6666 6+< < < 6N N6N 6 66 N6 N6N 66N :66 6 6:666 6666 6666 6+< < 6N 66N 6 6: 66 N6N 666 666 36-276 6666N 5295 uN< .u 66. 6N< u: _u 032 u:< U:< 6N< UN< 66 5360 E6 .86 6 66:66 6:30:65 630305: 50:66:06. 83000... GLSUV .u X-OZUQQ<