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V x, ‘1 fl _; ”3'; \th ’ i -, a L" ‘ . ~'~\ ‘.Lufz- ' ’ ;.- _. ffi.‘.) .§g ! I This is to certify that the thesis entitled Lithologic Control of Pressure Solution; Alpena Limestone, Alpena, Michigan presented by Timothy Montrose Buxton has been accepted towards fulfillment of the requirements for Masters degree in Geology Date May 17. 1983 0-7639 MS U is an Affirmative Action/Equal Opportunity Institution ’i- 7 LEN 21.41993l‘ MSU LIBRARIES an RETURNING MATERIALS: Place in book drop to remove this checkout from your record. FINES will be charged if book is returned after the date stamped below. LITHOLOGIC CONTROL OF PRESSURE SOLUTION; ALPENA LIMESTONE, ALPENA, MICHIGAN By Timothy Montrose Buxton A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Geology 1983 ABSTRACT LITHOLOGIC CONTROL OF PRESSURE SOLUTION; ALPENA LIMESTONE, ALPENA, MICHIGAN BY Timothy Montr ose Buxton Three distinct types of pressure solution features are f01md in the Alpena limestone (Devonian, Michigan): Stylolites, solution seams, and fitted fabric or intergranular pressure solution. Cementation is the fimdamental control on the type of features which deveIOp during pressure solution. Well cemented crinoidal grainstones typically have stylolites, whereas solution seams and fitted fabric texture are more common in poorly cemented grainstones, packstones, wackestones, and mudstones. Pressure solution occurs preferentially at lithologic transitions between rock types, due to competency contrasts of the units, rather than within homogeneous units. Material dissolved at pressure solution features does not appear to be locally reprecipitated, probably because the rate of fluid flow in the sediment exceeded the solute diffusion rate during pressure solution. The style of pressure solution in the Alpena limestone, and its relationship to cementation, is also observed in sandstones. TABLE OF CONTENTS List of Tables List of Figures Introduction Previous work on pressure solution Procedure Pressure solution in the Alpena limestone Lithologies in the Alpena limestone Cementation of the Alpena limestone Data Interpretation Comparison to a sandstone Conclusions BibliOgraphy Appendix A Dunham's classification according to depositional texture Appendix B Raw data and raw data summary tables Appendix C Comparison of distributions of pressure solution features in fitted fabric and non-fitted fabric lithotypes of the major lithologies in the Alpena limestone Appendix D Comparison of distributions of pressure solution features in all lithotypes of grainstones, packstones, and wackestones in the Alpena limestone ii ... iii iv 13 13 31 36 38 41 42 65 68 Table 1. Table 2. Table 3. Table 4. LIST OF TABLES Sample traverse line data Distribution of pressure solution features in fitted and nonfitted fabric grainstones Distribution of pressure solution features in grainstones vs. packstones Comparison of the percentage of each type of pressure solution feature within each lithology iii 19 20 22 Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7a. Figure 7b. Figure 7c. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. LIST OF FIGURES Classification of pressure solution features Dominant cement types in the Alpena limestone Fitted fabric grainstone Relict structure of partially obliterated stromatOporoid boundstone Recrystallized wackestone imit Syntaxial cement on echinoderm fragments Cementation predates pressure solution features Pressure solution removing cement and allochem Pressure solution removing cement and allochem Lack of reprecipitation of dissolved carbonates in fitted fabric texture zone. Type IA stylolite in neomorphosed wackestone Type IA stylolite in the Tuscarora sandstone Fitted fabric pressure solution in the Tuscarora sandstone Fitted fabric and solution seam pressure solution features in the Tuscarora sandstone iv 10 11 14 15 16 17 28 29 32 34 35 INTRODUCTION The purpose of this study is to determine the relationship between lithology and style of pressure solution in a shallow water carbonate se- quence. Because grain size and the presence of clay along grain boundaries will enhance the rate of pressure solution (Weyl, 1959), me could expect these variables to be important in determining the nature of pressure solution in sedimentary rocks. Also, thorough cementation during early diagenesis has been emphasised as the principal variable controlling the distribution of stylolites (in well-lithified wits) and solution seams (in less well-lithified mits) in chalks (Garrison and Kennedy, 1977). Although one would expect to observe predictable interrelations between lithology, cementation, and the style of pressure solution in limestones, such rela- tionships have not previously been defined. This paper is an attempt to define the relationships between lithologic variation, which is expressed by variations in texture and cementation, and pressure solution. This has been dme by a quantitative analysis of stylolites, solution seams, and intergranular pressure solution in the various lithologies of the Alpena limestone (Devonian, Michigan). The Alpena limestone was chosen for this study because of its abimdant pressure solution features, lithologic variability, and lack of deformation. Maximum depth of burial of the Alpena is 1500 meters (Hathon, 1979). 1 PREVIOUS WORK ON PRESSURE SOLUTION Pressure solution of well lithified rocks has been generally accepted as the mechanism responsible for formation of stylolites and solution seams since the early work of Stockdale (1926, 1943). Kerrich (1978) has recently comprehensively reviewed the subject. Pressure solution has been noted in many rock types, but is most commonly found in carbonates. Weyl (1959) suggested the most accepted view of the mechanism of pressure solution: solute ions migrate down chemical potential gradients, through a thin, quasi-liquid "solution film", capable of supporting a shear stress. Variations in chemical potential, and, therefore, chemical potential gradients, may be created by variations in contact pressure, structural state, impurity distribution, and crystallographic orientation. Rutter (1976), DeBoer (1977), DeBoer, et a1 (1977), and Robin (1978) strcmgly support Weyl's solution film hypothesis on thermodynamic and experimental grounds. Pressure solution has often been suggested as a cement-generating mechanism in sands and limestones (Waldschmidt, 1941; DLmnington, 1954, 1967; Oldershaw and Scoffin, 1967; Trurnit, 1968; Durney, 1972; Scholle, 1977). Many workers have stated that clay minerals may promote pressure solution by serving as avenues for diffusion (Heald, 1956; Weyl, 1959; Sibley and Blatt, 1976; DeBoer, 1977; Garrison and Kennedy, 1977), or by inhibiting cementation (Sibley and Blatt, 1976). Wanless (1979) attempted to relate pressure solution features to structural resistance (competentcy) and presence of clays in carbonates. He found that structurally resistant 3 units with little clay content deve10p sutured pressure solution features, whereas structurally responsive units with high clay contents deve10p solution seams and intergranular pressure solution. PROCEDURE All samples studied in this investigation were collected from the Middle Devonian Alpena limestone, exposed in the Huron Portland Cement quarry, located in R31N, T8E, section 31 in Alpena County, Michigan. A vertical sequence of samples was collected at one location and supplemental samples from the entire quarry were selected to obtain specimens of all lithologies at the site. Thin sections and acetate peels were prepared. Acetate peels were used because preliminary investiga- tions revealed that thin sections were often too small a sample of the rock to be useful in the analyses undertaken. Acetate peel procedures are out- lined in Bouma (1969). Ferroan calcite was known to occur in the Alpena materials and was differentiated by the application of a potassium ferri- cyanide stain (Lindholm and Finkleman, 1972) to thin sections and polished slabs before peels were taken. Methods of data collection and analysis are described in a latter section. PRESSURE SOLUTION IN THE ALPENA LIMESTONE There are three fimdamental styles of pressure solution in the Alpena limestone: stylolites, solution seams, and pervasive grain-to-grain solu- tion. Stylolites are serrated boundaries between units; the boundary usually has an accumulation of clay, oxides, and/or organic matter. The boundary 4 between two grains may be serrated, but is not considered to be a stylolite unless the feature extends beyond the individual grains. Solution seams are smooth, undulating boundaries between units, lacking the sutured form of stylolites; they also have an accumulation of clay or other material. These two major types of pressure solution features are recognized by Wanless (1979) in his classification. A third type of pressure solution feature, called "fitted fabric" pressure solution in this paper, consists of zones of intense intergranular pressure solution. Wanless (1979) includes this type in the solution seam group. The importance of "fitted fabric" textures as a major category of pressure solution features was recognized by Logan and Semeniuk (1976). Fitted fabric pressure solution differs from pressure solution along stylolites and solution seams in that fitted fabric dissolution occurs perva- sively throughout a zone, effecting all grains, whereas stylolites and solution seams are planar features. At stylolites and solution seams, only grains at the pressure solution surface are removed or presolved, while adjacent grains are uneffected. For the purposes of data collection, it was convenient to further subdivide the major categories (see Figure 1). There are two types of stylolites: type 1A and 1B. Type lB features are sutured, as are type 1A features, but the serrations are of higher frequency and lower amplitude. Fitted fabric pressm'e solution texture classification has also been subdivid- ed into two types. Intergranular pressure solution within a zone on the order of a few grains thick, and surrounded by material not showing 5 fitted fabric textures, is classified as a "limited fitted fabric" feature. "Unlimited fitted fabric" features are similar to the above, but are not constrained to a vertical dimension of a few grain diameters. Fitted fabric pressure solution is analogous to intergranular pressure solution and Trurnit's (1968) "network fabric". TYPE 1A STYLOLITE TYPE 1B STYLOLITE WW SOLUTION SEAM "LIMITED FITTED FABRIC" "UNLIMITED FITTED FABRIC" Figure 1: Classification of pressure solution features used in this paper. See text for discussion. LITHOLOGIES IN THE ALPENA LIMESTONE Alpena limestone deposition occurred in a shallow, normal marine environment (Ehlers and Kesline, 1970), during generally transgressive Traverse Group deposition (Gardner, 1974). Field work and examination of hand samples from the quarry indicate a generally shallow ing subtidal environment with possible tidal channel and minor reef deve10pment. The major lithologies sampled for this study are discussed below. Dlmham's (1962) classification of limestone has been used in this paper in a slightly revised form. Dunham's (1962) classificatim is shown in Appendix A. Grainstones consist primarily of clean, sand-sized skeletal material, dominantly crinoidal, with varying percentages of brachi0pods, bryozoans, corals, and other allochems. Two general types of grainstones can be distinguished within the Alpena materials; crinoid-dominated zones, with abtmdant syntaxial overgrowth cements and few pressure solution features, and pervasively presolved, less crinoid-rich units lacking evidence of substantial cementation. In the first type of grainstones, cementation by syntaxial overgrowths on crinoids is evident and abundant, while minor sparry cements are seen on multicrystalline substrates (see Figure 2). In the second type of grainstone, cementation is minor, and both crinoidal and other allochem grains are fitted in an interlocking pressure solution mosaic (see Figure 3). Packstones' contain a similar fossil assemblage in the sand-size fraction to the grainstones, although the percentage of crinoidal grains is lower. These sediments are poorly sorted, and commonly contain coarse 6 Figure 2: Dominant syntaxial overgrowth cements on crinoid fragments and minor sparry cement on brachio- pods. 80X scale = ISO/u Figure 3: Fitted fabric grainstone. Note fitted texture and lack of cementa- tion. 80X scale = 100 ,u 9 sand to pebble size bryozoan and coral fragments. The packstones contain 5 to 25% or more fine-grained matrix which reduces visible pore space. Where mud is locally absent, cementation appears well developed. Sparry cements are the dominant cement type in the packstones. Syntaxial over- growth cements occur on crinoid grains, but are less well-developed than in clean grainstones. Intergranular pressm‘e solution and solution seams are common features in packstones, generally found in zones apparently lacking cement. Well-cemented areas lack most pressure solution features. The wackestones in the Alpena limestone characteristically contain 10 to 50% coarse fossil fragments in a fine-grained carbonate matrix. Bryozoans, brachi0pods, stromatOporoids, and corals are the major fossils present, and generally show no sign of transport. Cementation features cannot be seen in the matrix of the wackestones, although intragranular cementation of the fossil fragments is commonly observed. Relict struc- tures from partially obliterated allochems and zones of increased grain size, due to recrystallization, are not Imcommon in the wackestones (see Figures 4 and 5). For the pm'poses of this paper, recrystallization is considered to be a form of cementation, whether or not sediment volume has been increased. Stylolites are virtually absent in the wackestones, and fitted fabric textures and solution seams are the most common pressure solutim fea- tures. Recrystallized wackestones show little deve10pment of pressure solution features, whereas recrystallization textures cannot be distinguished in highly presolved zones. 10 Figure 4: Relict structure of partially obliterated stromatOporoid bound- stone. 25X. Scale = 500 ,u 11 Figure 5: Recrystallized wackestone imit. 100x scale = 100 ,u 12 The mudstones from the Alpena contain few allochems (less than 10%); these are ostracods. Two distinctly different mudstones are found at the Alpena quarry and are not associated on the outcr0p. The first is a clean, porous, pelletal mudstone in which the ostracods are found, and the second is a shaley member of the Alpena which contains small horizmtal burrows, giving the rock a mottled, slightly nodular appearance. In thin section, fine, sparry cement can be seen in the pelletal rocks; cementation cannot be distinguished in the shaley Imit. Fitted fabric, solution seams, and limited fitted fabric pressure solution features are pervasive in the shaley member, although burrow-filling material lacks these pressure solution features. Btn'rows are accentuated by dissolution in the surrmmd- ing rock. Where pressure solution is seen in the pelletal unit, it common- ly occurs in well-defined planes or thin zones between porous, well- cemented areas. Units which can be classified as batmdstones are common throughout the other lithologies. Batmdstone units consist of intergrown skeletal matter. In the Alpena, these units are bryozoans, corals, and stromato- poroids. Sparry, intragranular cement is common in the interstices of the fragments. Pressure solution features deve10p around bomidstone imits in the surrounding sediments. Pressure solution features developed within boundstones, although very rare, have been observed in the rocks; in these cases, porous boundstones have been crushed by overburden, and pressure solution has occurred between fragments. CEMENTATION OF THE ALPENA LIMESTONE Most visible cement in the Alpena is rim cement on crinoid fragments in clean, well-sorted crinoidal grainstones (see Figure 6). Rim cements on crinoid fragments in other lithologies are less well developed, presum- ably because of inhibition of overgrowths by mud (Lucia, 1962) or other impurities. Intraparticle porosity in fossil fragments is often filled with sparry calcite. No evidence of vadose marine cements was fomd; i.e., no meniscus or gravitational cements, no vadose silt, no acicular or bladed spar, no micritic cements. Potassium ferricyanide staining revealed ferrous iron- rich zonation in both the rim and sparry cements. Cement, therefore, was probably formed in a fresh water, phreatic environment subject to fluctuating Eh/pH conditions. Where pressure solution features are in contact with cement, the featm'es trtmcate, and, therefore, postdate the cement (see Figures 7a, 7b, and 7c). DATA A comparison of the distribution of pressure solution features in various lithologies from the Alpena quarry has been imdertaken. Data were collected by traversing acetate peels of grainstones, packstones, and wackestones, normal to bedding, and counting the transitions from one lithotype to another lithotype, or to a pressure solution feature. Mud- stmes were not included in the data collection due to difficulties in dis- tinguishing individual pressure solution features in the pervasively presolved rocks, and lack of resolution in acetate peels. Thin sections were too 13 14 Figure 6: Syntaxial cement on echinoderm fragments. Note dominance of this type of cement over sparry cements developed on multi-crystalline sub- strates. Typical of clean crinoidal grainstones. 20X scale : 500 [a 15 Figure 7a: Cementation was essentially complete before development of pressure solution features. Note type 1A pressure solution feature cutting both allochem and cement, and note cement supporting allochem imder- going dissolution. 45X scale = 100 ,a 16 Figure 7b: Note pressure solution removing both cement and allochem in this photo- graph. ISOX scale = 30 fl 17 Figure 7c: Note pressure solution re- moving both cement and allochem in this photograph. Note fitted fabric texture developed above and beneath central pressure solution feature. Pressure solutiai of a distinctly dif- ferent style than Figures 7a and 7b. 25X scale = 500 ’44 18 small as samples of the rock for this quantitative evaluation. Type 1A, 1B solution seams and limited fitted fabric pressure solution features were recorded as separate variables, while the unlimited fitted fabric type features were listed with reference to the lithology in which they occm‘ed; e.g., fitted fabric grainstone (FFG). Unlike the other four pressure solution features, unlimited fitted fabric textures are units within which stylolites and/or solution seams may occur; hence, they were essentially recorded as a lith010gic type. Lithologies lacking fitted fabric type tex- tures were simply referred to as grainstones, packstones, or wackestones. During data collection, each feature or lithotype was defined at the point of intersection of the feature or lithotype with the traverse line, regard- less of lateral changes in the form of pressure solution or the lith010gic variables. An example of a traverse line is shown in Table 1. This traverse has three 1A grainstone transitions, two 1A b01mdstone transitions, one 1B grainstone transition, and one 1B fitted fabric grainstone transition as well as foru transitions between various lithotypes. Two himdred transi- tions were counted for each of four wackestones, 100 transitions for each of ten packstones, and 100 transitions for each of six grainstones. The raw data are found in the appendices. The data were analyzed by constructing 2 by 4 contingency tables such as Table 2. This table shows the number of transitions between the four pressure solution features and unlimited fitted versus nonfitted fabric grainstones. The chi-square statistic demonstrates that the solution 19 Table 1: Sample traverse line data. This traverse has three grainstone to type 1A pressure solution feature transi- tions, two boundstone to 1A transitions, one unlimited fitted fabric grainstone to type 1B stylolite transition, one grainstone to 1B transition, and fom' transitions from one lithotype into another. 1A (type 1A stylolite) GRN (grainstone) FFG (unlimited fitted fabric grainstone) GRN 1A BND (boundstone) 1A GRN FFG 1B (type 1B stylolite) GRN ‘ FFG 20 me o0 cum mm. mm om. .m mm. .: *bm.vH OO.N E .n. ma .wm Q. he .3 co .8 m. Bingo ~83. ocoumfiummw 3.5g Human—fl US$525 mwm mm .H mm .3 1000 0G OUSV' 5. .N um .53 53 35:09:00 383-38 m3. 8889.3 $5 83333 ma mucumfimuw 85mm 89.582 130% 25a Baa 8:83 Emom Sfifiom m: sarcasm 3 cannon AL @8305 8a m 55 mmofi wand? @3898 £25 mgflfimuwfl Hem won—Hg “cocoa quo 935$an .HwH u oBg H8330 “omdv n 358988 .6353an mo Eam 2.3.3 @9530: can mafia E manpower“ 8338 9530.5 mo 2832:me mo gmauwafioo .3865me "N 338. 21 featm'es are not randomly distributed between the two types of grainstone. It is obvious by inspection of the table that most (96%) of the type 1A transitions are with nonfitted fabric grainstones. Statistically significant differences (at the 95% confidence level) were also detected for unlimited fitted and nonfitted fabric packstones and wackestones (see appendices for contingency tables). In addition, all grainstone transitions (tmlimited fitted and nonfitted fabric) were compared with all packstone transitions in a similar fashion (see Table 3). A chi-square test shows the difference between the two lithologies is significant at the 95% confidence level. In fact, several individual components have chi-square values which exceed the critical value. All combinations of lithologies were fmmd to be signi- ficantly different at the a( = .05 level. All of the following pairs are significantly different: grainstone - packstone, grainstone - wackestone, and packstone - wackestone. The largest chi-square value was for the grainstone - wackestone comparison, and the smallest was for the pack- stone - wackestone comparison (see contingency tables in appendices). Differences in the portion of pressure solution features between lithologies were also statistically examined. For example, 20.5% of the solution features in grainstones are type 1A, whereas only 4.9% of features in packstones are type 1A. Assuming random samples and a binomial distribution, there is a significantly higher proportion (at ck = .05) of 1A featLues in grainstones (see Van Der Plas and Tobi, 1965, for confidence limits on binomial approximations). Test results are shown in Table 4. Type IA and limited fitted fabric features are difference in each lithology, 22 $2 won am 58. was 8.: 2.2: an: 23a Bun mam can S amass 3.3 5.5 $.12. 8.2. NE a: m 88m 898m $4.. a}. 84.8 .853 com 3... can M: 358988 3.8 «53-33 £13 SS Banana 3.3. N: E $8.823 ma 822.5 3 H38. moaumxwm =4 3865me :4 madam .mofiwofiofi: 95 on» 5 mogmom 8338 ogmmoa mo mgwfiflfimflv ofi monsoon 883% .88 6.85 :0.“ ooconowfiv “505%? .SK u 959 ~8an “no.2; u 3:089:00 mgvmnfio mo Esm .mooouwxoa mama? 3565me E magnum notion Panama mo 223$me mo “Sargasso an 633. 23 3.5a Btu M43 v M 8% .8. n K .8.w .QE v 2%: 88.30% ~85 8:9prme 5 madam 8338 no $880me Hmnmfim Eugflficmfim a .633 A ZMUV mmaoumxowa awfi mmgumfimuw E $5036 .3 09¢ mo mwflamoumm Buwmhm fiuawofiawfim .383 umtfim m 3 v.85... .038qu may £883on 98 3:03:33 mfiuanU .3205: some £53 9538 8338 99339 mo 0%... :08 mo 09880an 9: «0 82.3928 #83333 "v «Bah 24 while the percentage of type 1B and solution seams in grainstones is signi- ficantly different from that in packstones or wackestones. In addition, the combined percentages of type 1A and 1B stylolites are significantly different in each lithology. Type IA and 1B stylolites account for nearly 80% of pressure solution features in grainstones, 52% in packstones, and less than 40% of features in wackestones. The percentage of lithologic transitions; i.e., grainstone to packstone lithotype transition within a lithology, that had pressm'e solution features present at the transition, was also determined. In packstones and grain- stones, 81% and 75% of lithologic transitions have pressure solution features, whereas only 39% of the transitions in wackestones have these features. If, however, bomdstone to wackestone transitions are removed from the wackestones, then 84% of the lithologic transitions have pressure solution features. The rationale for removing bomdstone to wackestone transitions from consideration is that in a wackestone any dispr0portionately large fragment must be classified as a boundstone. This is not the case with grainstones or packstones which are better sorted and in which the original definition of the term "boundstone" (Dlmham, 1962) is more meaningful. Although not quantitatively examined, shaley mudstones show pervasive solution seams and unlimited fitted fabric texture deve10pment. They show no type 1A features. In the pelletal mudstones, anastomatising, sutured pressure solution features are well developed between clean, cement-rich 201188. 25 In summary, statistical analysis of the data shows that the various lithologies do respond differently to pressure solution. The greatest dif- ference in response is between grainstones and wackestones, and the least different in response are packstones and wackestones. In addition, most lithologic transitions have associated pressure solution features. INTERPRETATION Data analysis shows that there is a clear difference between various lithOIOgies and the style of pressure solution. Type IA stylolite seams are common only in nonfitted fabric grainstones. Solution seams are common in the other lithologies: unlimited fitted fabric grainstones, all packstones, and all wackestones. The fact that type 1A features did not occur in fitted fabric grainstones indicates that grain size is not the fundamental prOperty which determines whether stylolites or solution seams develop. There is a clear difference between unlimited fitted and nonfitted fabric grainstones which explains the difference in pressure solution features. Fitted fabric grainstones have very little cement, whereas the nonfitted fabric grainstones are well cemented. The cement in the nonfitted fabric grainstones is sub- strate controlled; most of the cement is rim cement on crinoidal fragments. Sparry calcite cement is found on scattered brachi0pods, but is much less abimdant than rim cement due to a slower growth rate (Lucia, 1962), and the relative paucity of non-crinoid fragments. Whereas all the crinoid fragments in the nonfitted fabric grainstones have overgrowths, most crinoids in the fitted fabric grainstones do not have significant overgrowths 26 (see Figures 6 and 8). Therefore, it is concluded that the most important difference between fitted and nonfitted fabric grainstones is the lack of cement in the fitted fabric. In an uncemented sediment, the maximum amplitude of a pressure solution feature is one grain diameter and, in most instances, amplitude will be much less. Type IA stylolites are, therefore, absent from unlimited fitted fabric zones because such units are not well cemented. Two grains within the fitted fabric zone may be structurally competent, and, therefore, have a sutured contact, but larger scale features (solution seams) will not. This is consistent with Wanless'(l979) classification, wherein he points out that stylolites are fmmd in clean, structurally com- petent mits. Obviously, competence is determined by cementation. It is reasonable to assume that cementation history is important to the response of packstmes, wackestones, and mudstones, also. However, it is more difficult to determine the degree of cementation of these rocks. These rocks contain scattered crinoid fragments, but they seldom have pro- minent overgrowths. Some fossils have an intraparticle sparry calcite cement, but the matrix is not displaced or replaced by cement crystals. Therefore, it is presumed that these rocks were not well cemented. Some samples were neomorphosed, and this can be considered a form of cementa- tion regardless of whether or not material has been added to the rock. Only one wackestone had a type 1A pressure solution feature and it occurred bet- ween a brachi0pod fragment and neomorphosed mud (Figm'e 9). Neomor- phism is inferred from the observation that the neomorphosed micrite 27 (microspar) was more coarsely crystalline than the majority of the micrite in the rock. Areas of neomorphism (microspar) in wackestones lack pressure solution features; where solution features are abundant, micrite, rather than microspar, is fmmd. The only area where a type 1A feature was found in a wackestone was as a boundary between two structurally competent units. The inference that cementation controls pressure solution may seem unlikely at first because many have suggested that much of the cement fmmd in sedimentary rocks may have been derived from pressure solution (Weyl, 1959; Renton, Heald, and Cecil, 1969; Durney, 1972; DeBoer, 1977; etc. ). The evidence indicates, however, that the material derived from pressm'e solution of the Alpena limestone was not locally reprecipitated. The grounds for this contention are the incomplete intragranular cementa- tion of still-porous allochems along stylolites and solution seams, and lack of cement in fitted fabric lith010gies (see Figure 8). One explanation for a lack of cementation associated with pressure solution is that pressure solution occurs in nonhydrostatically stressed sediments, often early in diagenesis (Friedman, 1975; Bathtn'st, 1975, p. 473). Under these condi- tions, the rate of fluid flow in the sediment will usually exceed the rate of solute diffusion along grain bomdaries. Therefore, solute concentrations will not bufld up in the pore fluids; because supersaturation is not achieved, precipitation does not occur. A fundamental difference between sedimentary and metamorphic rocks is that in metamorphic rocks, solute material is precipitated in pressure shadows (Ramsey, 1967; Kerrich, 1977), whereas Figure 8: Pressure solutim in fitted fabric tenure. Note lack of ap- parent reprecipitation of dissolved carbonate. 20X scale = 500 ,u Figure 9: Neomorphosed wackestone. Note type IA pressure solution feature which becomes a solution seam outside the field of view. This feature is developed bet- ween two weIl-lithified, structurally com- petent units, a neomorphosed wackestone and a boundstone. 1A features not seen elsewhere in the wackestone. 185x scale -25}, 30 solute material is not locally reprecipitated in sedimentary rocks. This can be directly attributed to fluid flow exceeding the rate of diffusion in sedimentary rocks, whereas in metamorphic rocks, diffusion is the major mechanism of transport. Thorough cementation was observed only in crinoidal grainstones. Rim cementation on crinoid fragments is not well deve10ped in the other rocks where pores contain micrite (Lucia, 1962). This may be analogous to inhi- bition of quartz overgrowths by clays (Pittman and Lumsden, 1968; Heald and Larese, 1974). It is reasonable that sparry calcite growth and neo- morphic grain enlargement are also inhibited by impurities. The greatest difference in response to pressure solutim (as shown by the chi-square tests) is between grainstones and packstones. This difference is interpreted to be due to well developed cementation in the grainstones. The least different units are the wackestones and packstones. If texture is the fundamental prOperty which controls the style of pressure solution, the grainstones and packstones should be more similar (lower chi-square value). The relative similarity between packstones and wackestones is due to the presence of cement-inhibiting mud. A second fundamental relationship which can be shown with the dam is that lithologic transitions commonly (80%) have pressure solution features. The following model is suggested. Two adjacent layers will respond to stress differently due to the differences in packing, cementation, etc. As a result of these differences, nonhydrostatic stress will be different in each unit. Pressure solution is driven by this nonhydrostatic stress, and the 31 rate of pressure solution in each unit will be proportional to sigma 1 minus sigma 3. Under normal stress, sigma 1 will be the same in all units, but sigma 3 will be less in the more competent unit (Robin, 1979). At the boundary between the two units, therefore, nonhydrostatic stress in the less competent unit is at a maximum, and a gradient for diffusion of solute from the less competent to the more competent unit is established. Lithologic boundaries, therefore, have a greater potential for pressure solution than intralithologic discontinuities. The same tendency for material to flow from less competent to more competent units is the cause of banding in meta- morphic rocks (Robin, 1979). COMPARISON T O A SANDSTONE The same fimdamental styles of pressure solution that occur in the Alpena limestone are also present in the Tuscarora sandstone (Silurian). The Tuscarora is a silica cemented, very clean quartz arenite. A few samples contain up to 17% clay, but the vast majority contain no more than 2%. The Tuscarora samples were studied as part of a previous investiga- tion of intergranular pressure solution (Sibley and Blatt, 1976). Pressure solution features are not as common in the Tuscarora as in the Alpena, although the same types of features are observed. Figure 10 shows a type 1A stylolite from the Tuscarora. Above and below the seam, the rock is well lithified with quartz overgrowth cement, which can be deduced by the dust rings on many of the detrital grains. This rock is texturally analogous to the well-cemented grainstones in the Alpena. Unlimited fitted 32 Figure 10: Type IA stylolite in the Tuscarora sandstone. Note cementation by well- developed quartz overgrowths. Arrows point to dust rings on detrital grains. This sample is texturally analogous to well-cemented grainstmes in the Alpena limestone. 240x scale = 50/“ 33 fabric pressure solution is seen in the Tuscarora in Figure 11. This fig- ure includes a plane light and a luminescence view of the same area. The luminescence photograph is used to distinguish luminescing detrital cores from nonluminescing authigenic overgrowths and fracture fillings. The dark areas in the luminescence photograph are voids (some due to plucking in sample preparation), not authigenic silica. In Figure 12, a solution seam is overlain by a well-cemented zone and underlain by a fitted fabric sand, lacking cementation. This is analogous to the presence of solution seams in the fitted fabric grainstones from the Alpena. Note the clay material in the fitted fabric zone. The fitted fabric texture has deve10ped because the clays have inhibited quartz overgrowth cementation. The three examples from the Tuscarora clearly demonstrate a rela- tionship between style of pressure solution and cementation similar to that prOposed for the Alpena limestone. Type IA stylolites are fOImd in well- cemented rocks, and solution seams and fitted fabric features are found in uncemented units. 34 Figure 11: Zone of fitted fabric pres- sure solution in the Tuscarora sand- stone. Note the lack of cementation. 17X scale = 500 /“ 35 Figure 12: Fitted fabric and solution seam pressure solu- tion features in the Tuscarora sandstone. Note the clay present in the fitted fabric zme. Clay has inhibited cementation, leading to fitted texture. Solu- tion seam has formed as clay minerals have accumu- lated during dissolution of grains in fitted fabric zone. 37.5X scale = 200/“ CONCLUSIONS 1) Pressure solution features in the Alpena limestones have been classified on the basis of morphology, and statistically significant relation- ships between different lithologies and pressure solution types have been delineated. 2) Type IA pressure solution features (stylolites) are found in well- lithified, nonfitted fabric materials, whereas solution seams are strongly associated with fitted fabric textures, developed in less well-lithified, poorly cemented sediments. 3) Clays and/or mud may be responsible for inhibiting cementation of crinoid fragments where present and may, therefore, influence the mode of pressure solution deve10ped and the type of pressure solution features ob- served. 4) Mud-free sediments will be most easily lithified. Later in dia- genesis, pressure solution will produce type IA pressure solution features. 5) Sediments which are less well-lithified will undergo essentially intergranular pressure solution throughout the section and will deve10p a characteristic fitted fabric texture. Solution seams deve10p within fitted fabric zones as insoluble material accumulates. 6) Material dissolved by pressure solution does not appear to repreci- pitate in the immediate vicinity of its origin as would be expected. This implies that the rate of fluid flow in the rocks undergoing dissolution is greater than the rate of solute diffusion away from areas of dissolution. This 36 37 is distinctly different from similar metamorphic reactions where, without benefit of adequate permeability and fluid flow, diffusion is local and repre- cipitation is immediate on the sides of grains normal to sigma 3. 7) Pressure solution features are deve10ped preferentially along trans- ition between lithotypes and, in general, deve10p along inhomogeneities within otherwise homogeneous rocks. 8) The style of pressure solution in carbonates and its relationship to previous cementation, is also f01md in sandstones. BIBLIOGRAPHY BIBLIOGRAPHY Bathurst, R. G. C., 1975, Carbonate sediments and their diagenesis: Elsevier, 658 p. Bouma, A. H., 1969, Methods for the study of sedimentary structures: Wiley - Interscience, New York, 458 p. De Boer, R. B., 1977, On the thermodynamics of pressure solution - interaction between chemical and mechanical forces: Geochim. Cosmochim. Acta, v. 41, p. 249-256. De Boer, R. B., Nagtegaal, P. J. C., and Duyvis, E. M., 1977, Pressure solution experiments on quartz sand: Geochim. Cosmochim. Acta, v. 41, p. 257-264. Dunham, F. J., 1962, Classification ofcarbonate rocks according to deposi- tional textm'e. In: Ham, W. E. (ed. ), Classification of carbonate rocks - a symposium, Am. Assoc. Pet. Geol. Mem. No. 1, p. 108-121. DLmnington, H. V. , I954, Stylolite deve10pment postdates rock induration: Jour. Sed. Petrology, v. 24, p. 27-49. Dimnington, H. V., 1967, Aspects of diagenesis and shape change in stylo- Iitic limestone reservoirs: Prcc. VIIth World Petrol. Congress, v. 2, n. 3, Mexico City, p. 339-352. Durney, D. W., 1972, Solution - transfer, an important geOIOgical deforma- tion mechanism: Nature, v. 235, p. 315-317. Ehlers, G. M. and Kesling, R. V., 1970, Devonian strata of Alpena and Presque Isle counties, Michigan: Mich. Basin Geol. Soc. Guide Book for Field Trips, p. 1-30. Friedman, G. M., 1975, The making and unmaking of limestones or the ups and downs of porosity: Jom'. Sed. Petrology, v. 45, p. 379-399. Gardner, W. C. , 1974, Middle Devonian stratigraphy and depositimal en- vironments in the Michigan Basin: Mich. Basin. Geol. Soc. Spec. Pap. No. I, 138 p. 38 39 Garrison, R. and Kennedy, W. 1., 1977, Origin of solution seams and flaser structtn'e in Upper Cretaceous chalks of southern England: Sed. Geol., v. 19, p. 107-137. Hathon, C. P., 1979, The origin of quartz in the Antrim shale: Impub. M.S. Thesis, Mich. State Univ. Heald, M. T ., I9 56, Cementation of Simpson and St. Peter sandstones in parts of Oklahoma, Arkansas, and Missouri: Jour. Geol., v. 64, p. 16-300 Heald, M. T. and Larese, R. E., 1974, Influence of coatings on quartz cementation: Jour. Sed. Petr010gy, v. 44, p. 1269-1274. Kerrich, R., 1978, An historical review and synthesis of research on pressure solution: Zentralblatt Fuer Geol. Palaont, Teil 1, H. 5/6, p. 512-550. Lindholm, R. C. and Finkelman, R. B., 1972, Calcite staining: semi- quantitative determination of ferrous iron: Jour. Sed. Petrology, v. 42, p. 239-242. Logan, B. and Semeniuk, V., 1976, Dynamic metamorphism; process and products in Devonian carbonate rocks, Canning Basin, Western Aus- tralia: Geol. Soc. Australia Spec. Pub. No. 6, 138 p. Lucia, F. J., 1962, Diagenesis of a crinoidal sediment: Jour. Sed. Petro- logy, v. 32, p. 848-865. Oldershaw, A. E. and Scoffin, T. P., 1967, The source of ferroan and non-ferroan calcite cements in the Halkin and Wenlock limestones: Geol. Jour., v. 5, p. 309-320. Pittman, E. D. and Lumsden, D. N., 1968, Relationship between chlorite coatings on quartz grains and porosity, Spiro sand, Oklahoma: Jour. Sed. Petr010gy, v. 38, p. 668-670. Ramsey, J. G., 1967, Folding and fracturing of rocks, McGraw-Hill, New York, 568 p. Renton, J. J., Heald, M. T., and Cecil, C. B., 1969, Experimental inves- tigation of pressure solution of quartz: Jour. Sed. Petrology, v. 39, p. 1107-1117. Robin, P-Y. F., 1978, Pressure solution at grain-to-grain contacts: Geochim. Cosmochim. Acta, v. 42, p. 1383-1390. 40 Robin, P-Y. F., 1979, Theory of metamorphic segregation and related processes: Geochim. Cosmochim. Acta, v. 43, p. 1587-1600. Rutter, E. H., 1976, The kinetics of rock deformation by pressure solu- tion: Phil. Trans. Roy. Soc. London, v. A-283, p. 203-219. Scholle, P. A., 1977, Chalk diagenesis and its relation to petroleum explo- ration: oil from chalks, a modern miracle?: Am. Assoc. Pet. Geol. Bull., v. 61, p. 982-1009. Sibley, D. F. and Blatt, H., 1976, Intergranular pressure solution and cementation of Tuscarora orthoquartzite: Jour. Sed. Petrology, v. 46, p. 881-896. Stockdale, P. B., 1926, The stratigraphic significance of solution in rocks: Jour. Geol., v. 34, p. 399-414. Stockdale, P. B., 1943, Stylolites: primary or secondary?: Jour. Sed. Petrology, v. 13, p. 3-12. Trurnit, P., 1968, Analysis of pressure solution contacts and classification of pressure-solution phenomena. In: Muller, G. and Freidman, G. M. (eds. ), Recent deve10pments in carbonate sedimentology in Central Europe, Springer, Berlin, p. 75-84. Van Der Plas, L. and Tobi, A. C., 1965, A chart for judging the reliabil- ity of point counting results: Am. Jour. Sci., v. 263, p. 87-90. Waldschmidt, W. A., 1941, Cementing materials in sandstones and their probable influence on migration and accumulation of oil and gas: Am. Assoc. Pet. Geol. Bull., v. 25, p. 1839-1879. Wanless, H. R., 1979. Limestone response to stress: pressm‘e solution and dolomitization: Jour. Sed. Petrology. v. 49, p. 437-462. Weyl, P. K., 1959, Pressure solution and the force of crystallization - a phenomenological theory: Jour. GeOphys. Res., v. 64, p. 2001-2025. 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