l4.G»S ; Cifc. 2oS & DIVISION OF THE ILLINOIS STATE GEOLOGICAL SURVEY JOHN C. FRYE, Chief URBANA CIRCULAR 308 1960 'LLINpIS STATE GEOLOGICAL SURVEY 3 3051 00004 1008 GEOCHEMISTRY OF CARBONATE SEDIMENTS AND SEDIMENTARY CARBONATE ROCKS Part IV-A: Isotopic Composition - Chemical Analyses Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/geochemistryofca308graf FOREWORD Detailed knowledge of the chemical and mineralogical var- iations that exist in the carbonate rocks limestone and dolomite and of the processes responsible for this diversity is fundamental to the Illinois State Geological Survey's program of furthering the practical utilization of these natural resources of Illinois. Chem- ical composition is particularly important when the rocks are used as agricultural limestone and fluxing stone or in the manufacture of dolomite refractories, lime, calcium carbide, sodium carbonate, glass, and other products. The invitation extended to Dr. Graf by the United States Geological Survey to prepare the chapter on sedimentary carbon- ates for their revision of F. W. Clarke's "Data of Geochemistry" has afforded a valuable opportunity for the state and federal geo- logical surveys to cooperate in a basic review of selected topics in carbonate geochemistry. The resultant material is presented in a series of Illinois State Geological Survey Circulars and subse- quently will serve as the basis for a condensed treatment in the revised "Data of Geochemistry . " Part I, published as Circular 297, includes an introduction and sections on carbonate mineralogy and carbonate sediments. Part II, Circular 298, presents the section on sedimentary carbonate rocks. Part III, Circular 301, deals with the distribution of minor elements . Part IV-A, Circular 308, discusses isotopic composition and presents chemical analyses. Part IV-B, Circular 309, contains the bibliography for the first four parts. Part V, concerned with aqueous carbonate systems, will be published with its own bibliography at a later date. *7*- John C. Frye, Chief GEOCHEMISTRY OF CARBONATE SEDIMENTS AND SEDIMENTARY CARBONATE ROCKS Part IV-A: Isotopic Composition - Chemical Analyses Donald L. Graf ABSTRACT The distribution of major and minor elements in sedimentary carbonate rocks and the mechanisms responsible for this distribu- tion are considered on the basis of published information contain- ed in geologic studies, and in studies of present-day environments of carbonate deposition, isotopic composition of carbonates, and experimental aqueous and nonaqueous carbonate systems. Part IV-A presents chemical analyses and discusses iso- topic composition. ISOTOPIC COMPOSITION OXYGEN ISOTOPES The relative abundances of the three stable oxygen isotopes, Ol6, O , and O^ 8 , vary in nature by as much as 10 percent; in air they occur in the pro- portion 99 .759 : .0374 : .2039 (Nier, 1950; Epstein, 1959). Craig (1957b) adopted a value for 10 5 (0 16 18 /0 16 16 ) of 413.97 for C0 2 produced by reaction of 100 percent HoPO* with the sample of Solenhofen Limestone on which Nier earlier measured precise isotopic abundance ratios. The National Bureau of Standards Solenhofen Limestone standard (No. 20) gives a value of 414.08. The fractionation factor of particular interest in carbonate precipitation is that for the reaction H 2 18 (1) + 1/3 CaC0 3 16 (s) - H 2 16 (1) + 1/3 CaC0 3 18 (s) Urey (1947), using a model that ignored the potential fields in the crystal, calculated the equilibrium constant K = 1.0220 at 0" C and 1.0176 at 25° C. These values rep- resent a -5.7° C change in temperature for l°/oo increase in O-'-vO^. McCrea (1950) obtained theoretical values of 1.0255, 1.0206, and -5.1 by including estimates of the effects of translational and hindered rotational degrees of freedom in the solid state. Equilibrium constants such as these, calculated from a theory for gases but applied to reactions involving condensed phases, must of necessity be of limited accuracy. Epstein et al. (1953) experimentally obtained -4.3" C/mil for present- day shells, a value in satisfactory agreement with McCrea's (1950) earlier experi- mental determination for inorganically precipitated CaCOo. [5] 6 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 Epstein (1959) stated that the fractionation factor in the CaC03-H 2 system has been shown to be independent of pH, of the relative amount of each phase, of the polymorphic form of CaCOn being precipitated, of whether fresh or sea water is involved (ionic strength), and apparently of pressure and of small amounts of Mg and Sr in the calcite structure. Laboratory experiments by McCrea (1950) and by Lowenstam and Epstein (1957) show that it is difficult to precipitate CaC03 rapidly enough from supersaturated but dilute solutions at the pH of ocean water so that oxygen isotope equilibrium is not attained. Clayton (1959) experimentally determined equilibrium constants in the tem- perature range 190° to 750° C for the calcium carbonate — water oxygen isotope exchange reaction, and in the range 9° to 19" C he computed them from the data of Epstein et al. (1953). Both sets of data fit very well the straight line described by In K - 2725 T~ 2 for which the equilibrium constant at 25 ° C is 1 .03187. The times required for iso- topic equilibration, starting with aragonite and adding NH^Cl to increase CaCO, solubility, lay between 100 and 1000 hours in Clayton's experiments. The oxygen isotopic composition of carbonate materials assembled in table 1 are expressed in permil units of 60^, where 60 is equal to , (Q 18 /Q 16 sample) - (Q 18 /Q 16 standard) ^ (0 18 /0 16 standard) ' Measurements from other laboratories, whenever possible, have been referred to the Chicago PDB standard (see Craig, 1957b). Some of the earlier results not included in this review were discussed by Ingerson (1953). The 6018 values for modern marine shells deposited in the temperature range 0° to 30° C in sea water of mean composition should range from about +1 .5 to -3.0°/oo, according to the temperature dependence defined by Epstein et al. (1953), and this is generally true (table 1). The 60-'- 8 values are of course affected by anything that changes the oxygen isotopic composition of sea water, such as the influx of fresh water from rivers and the addition of low-O-*- 8 water from the melting ice at high latitudes. Evaporation and condensation processes affect both the O iy /0 16 ratio of sea water and its salinity, so that there is a correlation, assumed to be linear (Epstein et al., 1951), between these two variables. In a nonglacial period, the expectable marine salinity variation from 33 to 37°/oo would result in a corresponding 60^° variation in CaC03 of 0.6 to 0.8^00, corresponding to 3° or 4 ° C (Lowenstam and Epstein, 1954). Possible changes in the isotopic composi- tion of sea water with geologic time have thus far been ignored, and the effect upon the large oceanic reservoir of precipitation of relatively small amounts of carbonates can be shown to be negligible. The observed 60-*- 8 values for modern shells are also a function of two var- iables peculiar to living organisms. Some organisms deposit CaC03 in only a por- tion of the total annual temperature range, and the mean 60*-° values for these shells are thus not those corresponding to the mean annual temperature (see Urey et al., 1951; Epstein and Lowenstam, 1953; Lowenstam and Epstein, 1954). The majority of the pelecypods examined by Epstein and Lowenstam at Bermuda seemed to grow primarily during periods of warm temperature, whereas all but one of the gastropod species seemed to show winter as well as summer growth. Some forms like Pinctada radiata include shell grown at low temperatures, whereas sessile foraminifera at Bermuda grow at very warm temperatures. Chama macerophylla lays down shell material only at temperatures above 21° C, although the annual water temperature range is 18° to 29° C. GEOCHEMISTRY OF SEDIMENTARY CARBONATES - I V-A 7 Epstein et al. (195 3) found that shells grown in sea water maintained at constant temperature were deposited in oxygen isotopic equilibrium with the water without any observable isotopic anomalies resulting from differences in the rate of animal metabolism. However, there is also evidence that some organisms deposit CaC03 out of equilibrium with the surrounding water. Lowenstam and Epstein (1957) showed that some of the algal carbonates from the Bahamas that they exam- ined, for which depositional temperatures from 22.8° to 39.8° C are indicated by the 60l8 values, must have formed out of equilibrium with the surrounding waters because the maximum temperature of the water is about 30° C. The mean tempera- ture calculated for a number of samples of oolites from the same area is, by com- parison, in relatively good agreement with the observed mean annual temperature. Present-day shoal-water coelenterates and echinoderms also apparently deposit CaC03 out of isotopic equilibrium, although Lowenstam and Epstein (1954) sug- gested that the measurements for the echinoids might be in error because of failure to remove all of the finely divided organic matter. Urey et al. (1951) noted that marine animals do not maintain body tempera- tures above that of the sea, so that the relationships discussed thus far are not complicated by this additional factor. These relationships would not, however, be expected to hold for air-breathing animals. The oxygen isotopic composition of shells and of carbonates in general may be altered after their formation by reactions involving isotopic exchange with water, such as dolomitization, aragonite-calcite transformation, and simple recrystalliza- tion of calcite, as well as by solid state diffusion. Urey et al . (1951) considered solid state diffusion and calculated that a crystal one millimeter on a side should retain 96 . 4 percent of its original concentration for7xl0 8 years at 20° C, or 6.4x10^ years at 100° C, relative to the equilibrium of a changed environment. The best I o indication of the preservation of original 60 values is the persistence of system- atic zonal variations of isotopic composition in shells, corresponding to seasonal temperature variations of the water in which the organisms lived. Belemnites, which are made up of large, closely fitted calcite crystals, have in some cases retained their original oxygen isotopic composition since Jurassic time (Urey et al., 1951). The temperature dependence of the 18 /0 16 ratio has been used to measure paleotemperatures, a subject not under consideration here. Such O 18 /© 1 ^ data are also of interest, however, as a measure of the range of isotopic compositions present in carbonate fossils and as a guide to the processes that went on in environ- ments of carbonate deposition. Emiliani in a series of papers (1955a, 1955b, 1956) reported on the oxygen isotopic composition of various species of pelagic foraminifera concentrated from Globigerina oozes encountered in Mediterranean and deep sea cores. The over-all 18 60 i0 range for several hundred such samples from the Pleistocene of the Atlantic and Pacific Oceans, +1.92 to -2.10, reflects the somewhat different depth-tempera- ture zones in which the various species lived, variations in isotopic composition of the water, and periodic Pleistocene oscillations of about 6° C in Atlantic surface ocean temperatures. Shorter ranges corresponding to more restricted temperature variations are shown by pelagic foraminifera of Pleistocene age from the Mediter- ranean, and those of Oligocene and Miocene age from the equatorial and subtropical Atlantic Ocean. Average 60 18 values for Atlantic and Pacific benthonic foraminifera of Pleistocene age are included in table 1 . In an extensive study of Upper Cretaceous fossils, principally from western Europe and the southeastern United States, Lowenstam and Epstein (1954) found that carefully selected brachiopods and pelecypods (genus Inoceramus), as well 8 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 as belemnites and a few polychaete worm tubes and scaphopods examined, gave reasonable temperatures indicating probable preservation of original 60^° contents. The brachiopods were noteworthy in giving 60^ values from . 6 to 1 . 3°/oo lower than those of the belemnites, but paralleling the variation of 60^° values of the belemnites with time. This relation was believed by Lowenstam and Epstein to be indicative of local bottom climates in which the brachiopods lived. Conversely, the parallelism of the brachiopod and belemnite values indicated that the belemnites give isotopic records of shelf seas, rather than of wide ranging migration routes. The over-all consistency of the belemnite data was shown by similar temperatures over a large area, with a latitudinal climatic gradient from the Gulf Coast of the United States to Scandinavia that is detectable for at least Maestrichian time. Many of the oyster shells, which are quite porous, would appear to have been in- filtrated by later O^-^-poor calcite deposited from fresh water. The enclosing chalks showed an unusually wide range of 60^° values and a mean 60^° value above that of the several fossil groups, a not improbable result, according to Lowenstam and Epstein, for variable mixtures of bioclastic debris supposedly consisting largely of the tests of planktonic organisms. Some of the chalks that have 60^ values corresponding to temperatures greater than 30° C would appear, however, to con- tain some light CaC03 introduced after original deposition. The existence of a temperature threshold for pelecypods but not for gastro- pods, described above for present-day forms at Bermuda, also is indicated by the higher 60^° values for gastropods relative to pelecypods in an assemblage of well preserved aragonitic fossils from the Upper Cretaceous Coon Creek Tongue of the Ripley Formation in western Tennessee (Lowenstam and Epstein, 1954). The interpretation of 60^° anomalies in fossil materials is thus seen to be an exceedingly complex problem, involving as it does consideration of secondary infiltration and possible equilibration with nonmarine waters, different temperature thresholds for growth, different temperatures of formation, possible migration of the organisms during life, variations in the isotopic composition of sea water re- sulting, for example, from influxes of glacial meltwater, and possible precipitation of organic CaCOo out of isotopic equilibrium. Ocean waters rarely vary in 6 0^ by more than 2°/oo. Fresh waters are var- iably depleted in O^ relative to ocean water, depending upon latitude and altitude, because of fractionation of oxygen isotopes during evaporation (Epstein and Mayeda, 1953). The variable O^ depletion is reflected in the variable isotopic composition of modern fresh-water carbonates (Baertschi, 1957; Clayton and Degens, 1959; table 1). The very light CaC03 deposit at the Pfafer spring is said by Baertschi to have formed on the walls of the spring shaft, where thermal vapor with 60^° = -22.5 (relative to the Chicago standard) regularly condenses. The two Miocene nonmarine limestones from Idaho (table 1) apparently were deposited in a lake at high elevation, and they seem to have retained their original isotopic composition. The work of Clayton and Degens (1959) indicated that Paleozoic marine limestones have typically undergone oxygen isotopic exchange with post-deposi- tional fluids of lower 0*° content until these limestones hardly differ from non- marine limestones in oxygen isotopic composition. Baertschi (1957) likewise found that virtually all of the nonmetamorphosed marine limestones he examined had 60-*-° values lower than those expectable for normal marine precipitation. Comparisons of the isotopic compositions of secondary calcite veinlets with those of the host (table 1) clearly illustrate the effect of such later infiltration. Samples from the marine Leadville Limestone of Mississippian age, in areas unaffected by hydrothermal activity, gave 60* 8 values that rather uniformly differ by about -6°/bo GEOCHEMISTRY OF SEDIMENTARY CARBONATES - I V-A 9 from those for carbonate laid down in isotopic equilibrium with sea water (Engel et al . , 1958). The difference and the uniformity of values suggested to Engel et al . that there had been extensive post-lithification isotopic exchange with connate or ground waters. The extent to which the oxygen isotopic composition of limestones will be altered by metamorphic or hydrothermal activity depends upon the volume of heated fluid associated with the process, as well as on the temperature and isotopic com- position of the fluid, and it is possible for recrystallization to occur with very little change in isotopic composition (see range of dO^° values for metamorphic carbonate rocks given by Baertschi, 1957). In the Leadville area, Colorado, the transition between isotopically unaltered limestone and that altered by hydrothermal activity is very sharp. Engel et al. (1958) found 0^° contents below the typical value for sedimentary limestone only in samples showing visual evidence of recrys- tallization. Limestone an eighth of an inch from the contact with a quartz-latite sill, or a few inches from narrow veins of hydrothermal dolomite and weak sulfide mineralization, had essentially the same isotopic composition as samples a thou- sand feet away. The temperature dependence of the oxygen isotope fractionation between quartz and calcite in isotopic equilibrium has not yet been measured in laboratory experiments. However, Clayton and Epstein (1958) have outlined this relationship from measurements of natural samples that are believed to have formed in equilibrium with large volumes of isotopically similar water and that therefore yield a straight line on a 6 quartz versus 6 ca j c ^ te plot. Several pairs of quartz and calcite samples from vugs that from geologic evidence appear to have formed at different times have isotopic compositions indicating that they are not equilibrium pairs. The difference in isotopic composition of the calcite and quartz decreases with increasing tem- perature, and is thus at a maximum for sedimentary materials (table 1). Comparable data for dolomite-quartz pairs plotted on a 6q Uartz versus "^dolomite diagram fall on a straight line with a slope of unity, indicating no isotopic fractionation be- tween the oxygen in these two minerals. Thus the isotopic fractionation between calcite-dolomite mineral pairs must be temperature dependent, although no measure- ments have yet been published. Isotopic analysis of a single mineral from a specific locality usually does not show that the mineral was in isotopic equilibrium with its surroundings when it was recrystallized (Engel et al., 1958), and thus isotopic examination of mineral pairs is highly desirable in the making of temperature estimates. Engel et al . found that,in the Leadville area studied, 60 18 values from single minerals had con- siderable significance. Nevertheless the differentiation between diagenetic and hydrothermal recrystallization of limestone that they were able to make using quartz-calcite pairs would not have been possible with, for example, calcite alone, because reaction with heated solutions and with nonmarine diagenetic solutions or ground water would both have resulted in decrease of 6 18 relative to that of marine carbonate . CARBON- 14 The radioactive isotope C 14 , with a half-life of 5568 ±30 years (Libby, 1955) is formed in the upper atmosphere by reaction between neutrons and N 14 , after which it quickly reacts with oxygen to form C 14 02- Although the cosmic ray neutron component is some 3.5 times greater in polar than equatorial regions (Simp- son, 1948; Yuan, 1949), the effectiveness of atmospheric mixing is shown by the fact that samples from various points on the earth's surface and in the atmosphere 10 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 agree within the statistical error of measurement (Libby, 1955). This error, given by Libby as some 3 to 5 percent, is now said by Brannon et al . (1957) to be less than 1 percent for contemporary concentrations of C^- 4 . Libby found no evidence that the intensity of cosmic radiation or the com- position of the carbon reservoir, predominantly contained in the oceans, has changed significantly in the last 20,000 or 30,000 years. More recent evidence has been cited by deVries (1959) for believing that there may be shorter term fluc- tuations in neutron flux as a result of solar activity. Craig (1954b) had earlier concluded from measurements of the C^ content of Sequoia growth rings that the isotopic composition of atmospheric carbon had been constant to at least l^oo from 1072 B.C. to 1649 A.D., and that irregular l^oo variations with a rough periodicity of about 400 years were more probably due to the effects of varying external conditions on the assimilation and respiratory processes of the tree than to atmospheric changes. Carbonate materials as encountered today should therefore to a first approxi- mation have a C^- 4 content that is simply the fixed percentage originally incorpor- ated by precipitation in equilibrium with the carbon reservoir, minus that lost since precipitation by decay of C^ . With present isotopic enrichment procedures (Haring et al., 1958), measurements of C 14 content have been attempted on materials as much as 70, 000 years old. Table 2, reproduced from Libby's book (1955), gives the Cl 4 content of modern shells. The average of these few measurements is 15.9 absolute disinte- grations per minute per gram. A value of 16.1 Dpm/g may be calculated from the average Dpm/g of 15 . 3 ± . 1 for samples from the terrestrial biosphere and the ratio c 13 ^inorganic C = 1.025 13 ^biological C which leads to a value of 1 .05 for the ratio c 14 inorganic C c 14 biological C (Libby, 1955; Craig, 1954a). However, it turns out that application of the equilib- rium ratio 1.05 is not justified, because the C^- 4 content of modern marine shells is governed by a steady state rather than an equilibrium situation. This conclusion has emerged from a series of papers, which are discussed next. Anderson and Libby (1951) and Kulp et al. (1951) reported that modern marine shells contained more C^ 4 than modern wood. And indeed, Craig's (1953) finding of higher C^ contents in marine carbonates than in organic carbon from marine plants and animals suggested that an even greater enrichment of C^ 4 , some 5 per- cent, should occur in the carbonates. However, additional measurements of marine shells by Suess (1954a, 1954b, 1955), deVries and Barendsen (1954), and Blau et al. (1953) all gave C* 4 contents essentially the same as that of modern wood. After showing that the low C* 4 activity of the shells cannot result from metabolic activity favoring deposition of C^ ( Craig (1954a) concluded that modern bicar- bonate in the surface waters of the ocean must have a radiocarbon age correspond- ing to the C 14 deficiency (see also Suess, 1955; Rafter, 1955). Craig (1957a) later showed this situation resulted to a small extent from the slow transfer of carbon across the atmosphere-ocean interface, but principally from a piling-up of radiocarbon in the atmosphere and the mixed layer of the sea because of the slow internal mixing of the sea. GEOCHEMISTRY OF SEDIMENTARY CARBONATES - I V-A 11 In special geographical areas, coastal upwelling of C^-poor deep waters probably contributes to the deficiency of C 14 in marine shells that grow there (Kulp et al . , 1952). Crane (1956) and Brannon et al . (1957) noted that many modern shells in estuaries and restricted bays have abnormally low C-*- 4 concentrations. Johnson et al . (1957) suggested that this effect is analogous to the "hard-water- lake" effect discussed by Deevey et al . (1954), but they reported good consistency for samples from open-bay areas. Post-depositional chemical changes involving replacement of some of the carbon atoms will, of course, alter the observed C^ 4 content. Armstrong and Schubert (1947) could detect no C 14 loss from C 1 -enriched BaC03 during a 40-hour experiment in which HoO vapor was absent. Unconsolidated soil carbonate from Bermuda showed no C^- 4 enrichment, indicating that when only solution and trans- port, and no redeposition, are involved, there is no C^ 4 exchange (Kulp et al . , 1952; Craig, 1954a). Furthermore, five surface calcareous loess and soil samples examined by Munnich and Vogel (1959) had C^ 4 contents of only 5 to 8 percent of the modern value. Broecker and Orr (1958) calculated the expectable effect for carbonates of varying porosity exposed to the atmosphere, but not to water, and claimed satisfactory agreement with experimental values obtained by analyzing CO2 from layers of natural sample successively farther in from the surface. The finding of 6 0*° contents in pelagic foraminifera from Pacific cores that correspond to surface temperatures similar to those observed today has been taken to indicate that oxygen isotopic exchange with the much colder bottom water has not taken place and that the C-*- 4 contents are likewise reliable (Arrhenius et al . , 1951). Similar reasoning has been applied to benthonic foraminifera of probable Oligocene age that give a paleotemperature higher than that of the present-day bottom waters (Emiliani and Edwards, 1953). Bartlett (1951), Godwin (1951), and Deevey et al . (1954) pointed out that dead carbon dissolved from old limestone by water containing CO2 in isotopic exchange equilibrium with the atmosphere may dilute the C^ 4 content of this CO2 by up to 50 percent. If CaC03 is precipitated from such waters before sufficient time has elapsed for reestablishment of isotopic exchange equilibrium with atmos- pheric CO2, it will have an abnormally low C^ 4 content. This phenomenon is ex- pectable in freshwater lakes, which have much smaller carbon reservoirs than those of the surface ocean and the atmosphere and whose carbon isotopic composition is thus strongly dependent on that of entering river and spring water and on the ratio of the flushing rate of the lake to the rate of exchange with atmospheric CO2 (Broecker and Orr, 1958). Caliche also presents a particularly complex problem because of the multiple solution and redeposition that has occurred at many local- ities. Deevey et al. (1954) have studied samples from Queechy Lake, New York, which lies on metamorphosed Paleozoic limestone and is fed by waters that seep through old limestone and limestone-rich glacial drift. The carbonate and bicar- bonate carbon in Queechy Lake water has a C-*- 4 activity appropriate for a solution, formed by atmospheric CO2 acting on old limestone, that has proceeded about half- way to equilibrium (table 3) . Some collodial CaCOg may have been included in this sample, obtained by acidification of water, but the C^ 4 activities of both in- organic and organic materials produced in the lake are low. Samples from Lake Zoar, Connecticut, which lies some 15 miles outside the region of limestone outcrop, are still deficient in C^ 4 , although less so than those from Queechy Lake. Isotopic exchange equilibrium is apparently not fully achieved in 15 miles by the relatively shallow river which flows from the area of limestone 12 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 outcrop into Lake Zoar. Blau et al . (1953) described marl from Pyramid Valley, North Canterbury, New Zealand, apparently deposited in a shallow, hard-water lake, which gives an excessive C 14 age relative to that of peat which underlies it. Deevey et al. (1954) suggested that in alkaline lakes in closed basins in semiarid regions not underlain by limestones, all of the carbon of the carbonate and bicarbonate in solution should be of atmospheric origin. Even if the streams were to dissolve some limestone containing only dead carbon, the presence of subsequent turbulent, high-gradient stretches in the streams could result in equi- libration with atmospheric CO2 . Broecker and Orr (1958), however, found a C 14 /C 12 ratio for tufa currently forming in Pyramid Lake, Nevada, that was 5 percent lower than that of wood grown on the shores of the lake after normalization for C^vcl2 difference. The decrease in the C^/C ratio of subaqueous plants in the lower portion of the Truckee River (which feeds Pyramid Lake), compared with that of the upper portion, indicated to Broecker and Walton (1959) that appreciable solution of carbonate from lacustrine sediments was taking place there. In their discussion of the geochemistry of C^ 4 in freshwater systems, Broecker and Walton also used their measurements of Great Basin samples to evaluate the dependence of C^ 4 concentration of dissolved bicarbonate upon rate of CO2 exchange across the water- air interface and upon the relative amounts of silicate and carbonate minerals dissolved by the system. Two factors have altered the C^ 4 activity of the atmosphere during historical time. Combustion of coal has diluted the activity by an amount whose mean world- wide value is probably about 1 percent, although dilutions of as much as 3-j per- cent may occur in industrial areas (Suess, 1955; Brannon et al., 1957). This so- called Suess effect typically has been determined by analyses of woods, but Bran- non et al. claim the effect, to the extent of 1 or 2 percent, is detected in compari- sons of open coastal water marine shells collected in 1850 and those collected today. Even more recently, the atmospheric C^ 4 activity has been increased by atom bomb explosions (Rafter and Fergus son, 1957; deVries, 1958). There has hardly been time for this effect to be detected in shells grown in larger bodies of water, which must first equilibrate with the atmosphere. STABLE CARBON ISOTOPES The ratio of the two stable carbon isotopes, C^2 and C* 3 , varies by about 5 percent in natural materials. Most carbonates are enriched in C* 3 relative to organic carbon, but some less common types of carbonates extend throughout the range. Craig (1957b) adopts for 10 5 (C 13 /C 12 ) a value of 1123.00 for the sample of Solenhofen Limestone on which Nier (1950) earlier measured precise isotopic abundance ratios. The National Bureau of Standards Solenhofen Limestone standard (No. 20) has a very closely similar ratio, 1122.53. During the depositional process, limestone becomes enriched in C* 3 some 0.3 percent, relative to the weighted mean for the active exchange reservoir of terrestrial plants + marine plants + ocean bicarbonate + atmospheric CO2 (Craig and Boato, 1955). The four components of the reservoir have, respectively, 2.5, 1.3, 0.2, and 0.7 percent less C 13 than average limestone. This slight increase of C 13 in limestone during deposition contrasts with a 0.9 percent depletion of C 13 for the over-all deposition of all sedimentary rocks, if a steady-state situation is assumed . Carbon isotopic fractionation factors have been calculated for two reactions of particular interest in aqueous carbonate systems and have been experimentally GEOCHEMISTRY OF SEDIMENTARY CARBONATES - I V-A 13 measured for one of them. For the reaction C 13 2 (g) + C 12 03 (aq) ^=^ C 12 2 (g) + C 13 03 (aq) Urey and Greiff (1935) used estimated vibrational frequencies and calculated frac- tionation factors of 1 .015 at 273. 1 ° K, 1 .012 at 298.1° K. They pointed out that constants such as the two given here, calculated from a theory for gases but ap- plied to equilibrium between a gas and an ion dissolved in water, must necessarily be unreliable. Urey (1947) made a second calculation based upon then available natural abundances as well as upon spectroscopic data, and obtained 1.016 and 1.012. Craig (1953) suggested, on the basis of more reliable isotopic ratios for marine limestone and air, that the fractionation indicated by Urey's values should be approximately halved, that is, they should be changed to 1 .008 and 1.006. McCrea's (1950) calculated values for the fractionation factor for the reaction C 13 0^ (aq) + C 12 03 (s) ==^ C 1 ^ (aq) + C 13 03 (s) between carbonate ions in the calcite structure and in aqueous solution are in agree- ment with the experimental values obtained when CaC03 is precipitated slowly; the factor is 1.0042 at ° C and 1.0038 at 25° C. CaC0 3 precipitated very rapidly has the same carbon isotopic composition as the solution from which it formed. Baertschi (1957) quoted a value of c = 1.010 at 26° C for the reaction C 13 2 (g) + C 12 03 (s) ^=^ C 12 O z (g) + C 13 Ol (s) based on unpublished experimental measurements. This number is the same as that obtained by multiplying together the fractionation factors for the two subreactions above, McCrea's 1.0038 and the 1.006 suggested by Craig. The fractionation factors for these reactions are seen to be temperature dependent, but a temperature effect has not been detected in natural sedimentary materials, where it is presumably masked by other larger effects discussed below. Although Jeffery et al . (1955) interpret some of their results in terms of changing isotopic composition of the carbon reservoir as a function of periodic diastrophism, most other workers are not convinced of the existence of this age effect (see also Compston, 1960). The aqueous carbon reservoir, present chiefly as dissolved bicarbonate, is about 3x1 0^ times smaller than the aqueous oxygen reservoir present as water (Baertschi, 1957), and thus the opportunity for local variations in reservoir composi- tion are much greater for carbon. Jeffery et al. (1955) discussed the probable inter- relationships among the carbon isotopic compositions of the several C-containing phases in closed aqueous systems, where the carbon reservoir no longer can be considered infinite relative to the amount of solid carbonate. Experimental data are generally not yet available for comparison with these theoretical predictions. Variations in the C i0 /C ratios of limestones were said by Craig (1953) to result from (1) variations in isotopic composition among the skeletal carbonates laid down by various organisms in the same environment; (2) local change in the composition of the aqueous carbon reservoir in the neighborhood of marine plants extracting C0 2 for photosynthesis; (3) possible equilibration of carbonate with organically derived C0 2 ; and (4) rate of carbonate precipitation. Values from a number of laboratories, assembled in table 4, may now be examined in terms of 14 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 these effects. The values based on the Chicago CO, standard have always been reported in units of 6C^^°/oo, where 6C 13o /oo= C / gl sample - C /C standard x 10Q0 C 13 /C 12 standard Values from other laboratories have here been converted to 6C* 3 (Chicago standard) wherever possible, using the relationships published by Craig (1957b). Some earlier results not included in this review have been discussed by Ingerson (1953). Landergren (1954) published numerous carbon isotopic analyses demonstrat- ing the occurrence of higher C12/Q13 ratios in Swedish limestones formed in envi- ronments where the contribution of large amounts of Cl2_rich CO2 from decompos- ing organic matter would be expectable. The gray Limbata Limestone, not so highly oxidized as the red variety, is found in areas corresponding to the deeper parts of the depositional basin and has a markedly higher B/Al ratio, indicating higher salinity and thus greater distance from nearshore freshwater influxes. The critical factor is the ratio in the immediate depositional environment between CO2 of organic origin and that from the surface layer of the sea (shells, dissolved CO2) in equi- librium with the atmosphere. A higher percentage of the available organic matter was oxidized in the depositional environment of the red Limbata facies, but equi- libration with the atmosphere was apparently maintained. Landergren 's bituminous limestones are also somewhat enriched in C*^ relative to typical open marine limestones, but it is the small amounts of carbonate contained in red clays and shales that show the greatest C^2 enrichments. Silverman and Epstein (1958) reported several 6C-'- 3 values for organic ma- terial contained in carbonate sediments. The material extractable with a 4: 1 chloroform: methanol mixture from a core taken in the shallow water of Florida Bay, Florida Keys, gave values from -20.3 to -26.2°/oo at depths in the 60-inch to 80-inch range. The total organic matter in the surface mud off Lignum Vitae Island in the Florida Keys averages -13.5°/oo. In distinguishing between marine and non- marine environments, it appears to be significant that the 6C^ 3 values of petroleums and organic extracts from marine sediments range from -22.2 to -29.4°/oo, whereas those for comparable organic materials derived from nonmarine sediments range from -29.9 to -32.5°/oo. Mere contiguity of organic matter and carbonate does not of course indicate that isotopic exchange has occurred. Wickman (1953) found that the C^/c 13 ratios of most of the carbonates present as small amounts in coal that he examined did not indicate that significant amounts of CO2 of organic origin had participated in their formation. Although agreeing with Landergren 's interpretation of the Swedish carbonates, Jeffery et al . (1955) noted a poor correlation in Australian limestones between iso- topic composition and oxidation state as revealed by color and suggested that other factors may be involved. However, their samples were from widely scattered sources, geologically and geographically, and they did not compare, as Landergren did, large numbers of samples from different facies of the same horizon. The general lowering of 6C 13 values of cold-water carbonates (from caves, soil concretions, and other such sources) below values expectable for carbonates formed from normal atmospheric C0 2 was attributed by Baertschi (1957) to the incorporation of CO2 derived from oxidation of organic matter in the water and in soil humus zones. The secondary carbonate veinlets examined by Baertschi always GEOCHEMISTRY OF SEDIMENTARY CARBONATES - I V-A 15 contained less C^ than did the host rocks. Vogel (1959) stated that in freshwater carbonate deposition C^-poor CO2 formed in the soil humus zone by humus de- composition and by plant-root respiration is important. Craig (1953) likewise con- cluded that his extremely light travertine, tufa, and stalactite carbonate values probably resulted from equilibration of carbonate with organically-derived CO2 (see also the results of Munnich and Vogel, 1959). The high 6C^ values for Baertschi's Engadine tufas and that for cold-water travertine precipitated from the Tivoli River (Craig, 1953) are striking exceptions to the generalization suggested by these several authors. Vogel (1959) suggested that isotopic equilibration be- tween magmatic CO9 (derived from thermal decomposition of limestone) and bicar- TO bonate in solution could yield a solution capable of precipitating these C ±0 -rich travertines. The samples of calcite from salt-dome caprocks described by Thode et al . (1954) and by Feely and Kulp (1957), the lightest carbonates recorded thus far, have 6C13 values as low as -51^00. The isotopic compositions found for C and S are reasonable for a process involving bacterial reduction of sulfate to form H2S and S, and oxidation of organic matter to CO2 and H2O (see also Ault, 1959). Formation of the calcite and sulfur by a localized process involving organisms also is suggested by the isotopic variations of C and S in the same core sample. The relatively heavy CaCO~ found by Craig (1953) in chalks, and the even greater 0*3 content of CaCO^ from modern marine plants (algae) led him to postulate that algal withdrawal of Cl2_ r i c h CO2 for photosynthesis had changed the pH of the surrounding water and led to precipitation of the C^-rich CaC03 making up the chalks. Urey et al. (1951) had noted earlier that 6C^ values for belemnites of Upper Cretaceous age showing apparently unaltered 60^° values were erratic, and ascribed the variation to fractionation of C isotopes by plants and a consequent large effect on the relatively small carbon reservoir in the ocean. Although some of the chalk matrices examined by Urey et al. are lighter than the contained fossils, both chalks and fossils are significantly heavier than modern invertebrate skeletal material (see table 4) . The carbonates in the lacustrine Green River Formation have a high 6C^ value of about 2°/bo, in sharp contrast to the -31 .9°/oo for the associated organic matter (Silverman and Epstein, 1958). Not only has post-depositional exchange between carbonate and organic material obviously not occurred to any significant extent, but the extreme spread in the two values appeared to Silverman' and Epstein to require explanation. They suggested that concurrent algal photosynthesis and carbonate precipitation took place in a thermally stratified lake whose warm sur- face-water layer was relatively poor in bicarbonate because of the algal activity. Support for this model is given by Wickman's (1952) finding that lacustrine plants living in stagnant water have 6C^ values averaging 8.8°/oo less than those from nonstagnant water. Craig (1954a) obtained aC 1 ^ range of 9°/oo for freshwater plants grown in stagnant tanks, correlatable with the amount of carbonate precip- itated, and suggested that rate and source of supply of CO2 are critical. The bC^ values for freshwater limestones (Clayton and Degens, 1959) are consistently lower than those for marine limestones (table 4). The same relation was noted for seven carbonate fractions present to the extent of 2 to 5 percent in marine and nonmarine sandstones, but no such regular relationship was found in the C isotopic composition of a number of carbonates examined that make up less than 0.5 percent of somewhat bituminous shales of Pennsylvanian age. The con- tribution from detrital carbonate fragments may become important in the latter case, and the concentration of both living organisms and decaying organic matter in the depositional environment makes possible either enrichment or depletion of C*3 i n the carbonate, depending upon the immediate local situation. 16 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 The preservation of most of the 6C^ differences between nonmarine and marine carbonates, even for Paleozoic rocks, is in contrast to the behavior of oxygen isotopes in the same samples. Wickman and von Ubisch's early (1951) finding that two generations of calcite crystals in a vug in reef limestone of Silurian age were successively poorer in C^ than the limestone suggests incom- plete equilibration of the rock with nonmarine waters in contact with organic matter. Craig (1953) suggested that the high C^ content of oolite of Cambrian age from Tyrone, Pennsylvania, resulted from rapid precipitation in shallow, strongly agitated water. However, this explanation seems a dubious one in view of labora- tory experiments by Lowenstam and Epstein (1957) that show it is difficult to pre- cipitate CaC03 from supersaturated but dilute solutions at the pH of ocean water rapidly enough to prevent isotopic equilibrium from being attained. The carbon isotopic compositions of several dolomites analyzed by Wickman et al. (1951) fell in the heavier part of the range for limestones. Craig (1953) gave a few more analyses and concluded that not enough data were available to justify concluding that the relationship observed by Wickman holds generally. MAGNESIUM ISOTOPES Daughtry et al. (in press) measured Mg^ 4 /Mg values in traverses across tectonically localized dolomite bodies and found the ratios progressively lower for samples successively farther from faults. ACKNOWLEDGMENTS I am indebted to W. F. Bradley, R. N. Clayton, Harmon Craig, R. M. Gar- rels, J. R. Goldsmith, J. E. Lamar, P. E. Potter, Raymond Siever, K. K. Turekian, and H. B. Willman for critically reading part or all of the manuscript. The respon- sibility for errors, omissions, and distortions that may occur is, of course, mine. Michael Fleischer, Irving Breger, and V. E. McKelvey of the U. S. Geological Sur- vey have been particularly helpful in supplying references, chemical analyses, and translations. I am grateful to my colleagues in the carbonate field who have been so generous in discussing their current activities and can only hope that the sum- mary that has resulted may be of some use to them. Suggestions for improvement of the material contained in Parts I, II, III, and IV and in the forthcoming Circular on aqueous carbonate systems (Part V) will be helpful in preparing the chapter on sedimentary carbonates for "Data of Geochemistry, " in preparation by the U.S. Geological Survey. GEOCHEMISTRY OF SEDIMENTARY CARBONATES - IV-A 17 TABLE 1 - OXYGEN ISOTOPIC COMPOSITION OF CARBONATE SEDIMENTS, SKELETAL MATERIALS, AND ROCKS I Q In units of 60 relative to the Chicago PDB standard (Craig, 1957b) Only the values of Clayton and Degens (1959) have been corrected for dif- ference of C-L3 content of sample and standard, the second term in Craig's equation 6 18 =1.0014 6 + 0.009 6C 13 c m 13 For the range of C contents of natural carbonates, neglect of this correction would cause a false spread in 6 0^° of 0.6°/oo. Baertschi's (1957) values, for which he assumed 6 C = 6 m, represent a further degree of approximation, although for small values of 60^-° neither of the two corrections is important. The analytical fractionation introduced during treatment of the Ca-Mg carbonate samples with 100% H3PO4 at 25°C, which liberates only two-thirds of the oxygen in the carbonate, was assumed by Clayton and Epstein (1958) and Engel et al, (1958) to be the same as the 1.010 value determined by Clayton and Epstein for MnC03» from which all the oxygen can be extracted by a carbon reduction method. Clayton (1959) now reports 1.0075 for CaC03» based upon an extrapolation of experi- mental data to K = 1, and use of this value would reduce quartz-calcite fraction- ations reported below by 2.5°/oo. If the analytical fractionation differs for different carbonates, the further possibility exists that the dolomite data should be shifted by an unknown amount. Material 60 in /oo Pleistocene pelagic foraminifera, Atlantic and Pacific Oceans (Emiliani, 1955a) Range -2.10 to +1.92 Pleistocene benthonic foraminifera (Emiliani, 1955a) Atlantic Ocean, glacial periods Av. +4.07 Atlantic Ocean, interglacial periods Av. +2.84 Pacific Ocean, glacial periods Av. +3.68 Pacific Ocean, interglacial periods Av. +3.45 Bahama Bank materials (Lowenstam and Epstein, 1957)* 23 algal aragonites Range -3.1 to +1.5 Av. -1.0 9 samples, sedimentary aragonite needles Range -0.5 to +0.5 Av. +0.1 12 samples, oolites and grapestones Range -0.4 to 0.0 Av. -0.1 3 serpulid worm tubes, Salmacina sp. -0.4, -0.4, +0.7 Venus sp., modern, marine (Clayton and Degens, 1959) -1.37 71 modern mollusks, Bermuda (Epstein and Lowenstam, 1953) Range ~1.8g to +O.47 33 mollusks from interglacial Pleistocene deposits, Bermuda (Epstein and Lowenstam, 1953) Range -1.1 2 to -O.O4 UniO sp., modern, nonmarine (Clayton and Degens, 1959) -7.42 Helix sp., modern, nonmarine (Clayton and Degens, 1959) -8.46 Modern Hawaiian lake mud, nonmarine (Clayton and Degens, 1959) -8.39 Pleistocene age varved clay, New York (Clayton and Degens, 1959) -8.05 Four calcareous tufas, Engadine springs Range -10.6 to -9.4 (Baertschi, 1957)** Av. -10.2 White carbonate precipitate, Pfafer spring (Baertschi, 1957)** -21.4 Calcareous concretion in loam (Baertschi, 1957)** -6.3 Calcareous onyx, Pueblo, Mexico (Baertschi, 1957)** 0.0 Range -2.83 to -1.4 6 Range -3.68 to -I.85 Range -2.O3 to -0.4 Range -3.8 5 to -1.8 Range -0.4 3 to -O.O9 18 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 TABLE 1 - continued Material 60 in /oo 6 other freshwater deposits (Baertschi, 1957)** Range -4.7 to -20.2 Av. -9.1 40 specimens Belemnttella americana, Upper Cretaceous, southeastern U. S. (Urey et al., 1951) Range ~0.4 3 to -O.O9 Upper Cretaceous of England (Urey et al., 1951) 8 brachiopods 11 oysters 6 belemnites 11 chalk matrices Three Danish belemnites (Urey et al., 1951) Albian and Upper Cretaceous age samples, mostly from western Europe, southeastern United States (Lowenstam and Epstein, 1954) 191 belemnites 10 brachiopods 19 Inoceramus fragments 51 Ostreidae 63 associated chalks 11 Paleozoic marine limestones (Clayton and Degens, 1959) Two nonmarine Miocene age limestones, and an included fossil, Idaho (Clayton and Degens, 1959) Two nonmarine Tertiary age limestones, Kansas (Clayton and Degens, 1959) 10 nonmarine Pennsylvanian age limestones, Pennsylvania (Clayton and Degens, 1959) 4 marine limestones, comparison of matrix with calcite veins (Baertschi, 1957)** Belemnite, Gallovien age (Baertschi, 1957)** Crinoids from Carboniferous-Devonian age limestone (Baertschi, 1957)** Olenus truncatus, Upper Cambrian (Baertschi, 1957)** 4 Devonian age brachiopods from Australia that probably have undergone post-depositional isotopic re-equili- bration (Compston, 1960)t 24 Permian age brachiopods from Australia, believed to be isotopically preserved (Compston, 1960)t Calceolispongia', basal plate, Permian of Australia (Compston, 1960)t Precambrian age dolomite (Baertschi, 1957)** Precambrian age algal limestone (Baertschi, 1957)** 15 other limestones, Tertiary to Ordovician age (Baertschi, 1957)** 6 samples of Leadville Limestone, Mississippian age, Colorado, 2 dolomitic (Engel et al., 1958)* <50l° determinations for quartz-calcite pairs, given in that order (Clayton and Epstein, 1958)* Black chert in chalk; Cretaceous} France +4.5, -2.7 Black chert in Mississippian limestone, Fulford, Colorado -0.3, -6.7 Range -2.9 7 to +0.8e Range -2.83 to -0.0 2 Range -3.56 to +0.1! Range -3.8o to -O.64 Range -3.7 4 to -0.3 3 Av. -2.O3 Range -12.48 to -5.11 Av. -8.48 Range -18.49 to -16.79 Av. -17.88 Range -7.39 to -6.67 Av. -7.03 Range -9.00 to -5.04 Av. -7.26 -4.6, -6.4 -3.0, -9.6 -5.2, -6.6 -3.3, -4.2 0.0 -2.3 -7.4 Range -5.5 to -3.6 Range -3.7 to +2.2 Av. -0.5 -6.8 -6.8 -5.4 Range -6.1 to -2.8 Av. -4.2 Range -8.3 to -0.9 Av. -4.9 GEOCHEMISTRY OF SEDIMENTARY CARBONATES - IV-A 19 TABLE 1 - continued Material Small calcite crystals embedded in "Herkimer diamonds" (quartz crystals in cavities in dolomite), Herkimer County, N.Y. Black chert in recrystallized Mississippian limestone; Fulford, Colorado Chert and dolomite in Leadville Formation, Meeker, Colorado Quartz and recrystallized dolomite, Marble, Colorado 60 18 / in /oo -5, .5, -10.7 -7, .2, -11.6 -1 .8, -0.9 -6 .4, -6.4 * Salinity variations in the various waters from which these samples were collec- ted resulted in the waters' having 60 18 values from about +1.6 to +3.2 relative to mean ocean water. If the carbonate 60 18 values are corrected to what they would have been if deposition had taken place from water having 6 18 = 0, the average 6o 18 for algal aragonite becomes -3.1, for aragonite needles, -2.7, for oolites, -1.8. t Not including determinations that Compston indicated may be irregularly up to 2.0 °/oo too positive because of variation in the temperature at which carbonate decomposition was carried out. ** Reported as 60 relative to the Basel standard, and here converted to 60 relative to the Chicago standardising the relation given by Craig (1957b). 18 t- Reported as 60 relative to Hawaiian ocean water and to mean ocean water, whose difference of 0.2 °/oo was ignored, and here computed as 60 1 ° relative to the Chicago PDB standard using the relation given by Clayton and Epstein (1958): 6 OW =1 ' 02956 PDB +29 - 5 TABLE 2 - C 14 ACTIVITY OF CONTEMPORARY SHELLS In absolute disintegrations per minute per gram (after Libby, 1955) All analyses quoted from other laboratories have been reduced by Libby by assuming that the modern wood assay is in perfect agreement with his average value for terrestrial biosphere samples, 15.3 ± 0.1 Dpm/g. The values given by Kulp et al. (1951) have since been reported to be too high (see Craig, 1954a). Four seashells from Lower California (Suess, 1954b) Six clam shells, New York (Kulp et al., 1951) Bikini coral (Halimeda debris) (Kulp et al., 1951) Clam shells, Aleutians (Kulp, Tryon et al., 1952) Eleven mollusk shells, North America (Blau et al., 1953) Same, excluding two high values at 17.8 and 17.2 Murex shell, Florida Fresh ocean sediment, Bermuda Oyster, Chesapeake Bay 15.3 ± 0.2 16.9 ± 0.3 16.9 ± 0.3 13.3 ± 0.5 15.8 ± 0.2 15.4 ± 0.2 17.1 ± 0.5 17.4 ± 0.5 15.1 ± 0.5 5.86 ± 0.08"! 6.15 ± 0.08J Average 6.02 4.60 ± 0.10 5.02 ± 0.10 5.07 ± 0.10 5.02 ± 0.11, 5.09 ± 0.11 4.99 ± 0.11, 5.18 ± 0.16 5.20 ± 0.14, 4.87 ± 0.07 4.83 ± 0.11, 4.82 ± 0.08 4.68 ± 0.09, 4.97 ± 0.15 6.00 ± 0.10 20 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 TABLE 3 - C 14 ACTIVITY OF MATERIALS FROM QUEECHY LAKE, NEW YORK (After Deevey et al., 1954) In counts per minute Average of modern woods, Connecticut Submerged vegetation, Conn, soft-water lakes CO2 from CO3 and HCO3, Queechy Lake water Chara sp. , inorganic calcareous material Organic carbon Potamogeton sp. , inorganic calcareous material Organic carbon Elliptio complanatus, shell Soft parts Deep-water muds Scirpus sp. (emergent) TABLE 4 - STABLE CARBON ISOTOPIC COMPOSITION OF CARBONATE SEDIMENTS, SKELETAL MATERIAL, AND ROCKS In units of 6C relative to the Chicago PDB standard (Craig, 1957b) Values in parentheses are expressed relative to other standards for which conversion factors are not available. Only the values of Baertschi (1957), Clayton and Degens (1959), and Compston (i960) have been corrected for differen- ces in 0*' abundances of sample and standard, in addition to the customary cor- rection for the 0l7 content of the standard. For the range of oxygen isotopic compositions encountered in carbonates, the former effect corresponds to a spread of 1 0/00 in C 13 . Material 6C in /oo Atmospheric CO2 (Craig, 1953) Atlantic Ocean bicarbonate (Craig, 1954a) Modern pelagic foraminif era, equatorial Atlantic (Craig, 1954a) Modern pelagic foraminifera, equatorial Pacific (Craig, 1954a) Modern skeletal carbonates (Craig, 1953) Echinoderm, Arbacia Echinoderm (starfish) Gastropod, Leucozonia ciniulifera Coral, Porites porites Gastropod, Fasciolaria tulipa Five modern marine algal carbonates (Craig, 1953) Same, excluding value of -4.5 Bahama Bank materials (Lowenstam and Epstein, 1957) 23 algal aragonites 9 samples, sedimentary aragonite needles 12 samples, oolites and grapestones 3 serpulid worm tubes, Salmacina sp. 12 modern marine mollusks (Craig, 1954a) -7.4 to -9.9 -1.3 to -2.9 +1.2 +1.9 -3.5 -5.9 -0.3 -1.4 +0.4 Range -4.5 to +4.3 Av. +2.0 Range +3.1 to +4.3 Av. +3.6 Range +0.1 to +5.9 Av. +3.8 Range +2.8 to +4.9 Av. +3.6 Range +3.2 to +5.2 Av. +4.7 +2.6, +3.7, +4.2 Range -3.8 to +1.9 Av. -0.1 GEOCHEMISTRY OF SEDIMENTARY CARBONATES - IV-A 21 TABLE 4 - continued , „13 . 0/ ou in /oo 1960) 10 carbonate samples from basin sediments off southern California (T. A. Rafter, in Emery, 7 samples, carbonate from Romanche Deep core, Atlantic Ocean, S 00° 07', W 18° 12' (Landergren, 1954)* 4 samples, small amounts of carbonate in red clays, Pacific (Landergren, 1954)* 13 freshwater deposits (concretion, fissure filling, cave and spring deposits) (Munnich and Vogel, 1959) 5 surface samples of calcareous soil and loess (Munnich and Vogel, 1959) Caliche, Kansas (Craig, 1954a) Travertine, Tivoli River, near Rome (Craig, 1953) "Hot water ice" (CaC03 crust on surface of still pools), Angel Terrace, Yellowstone National Park (Craig, 1953) "Globular shells" (CaC03 formed around gas bubbles), Angel Terrace, Yellowstone National Park (Craig, 1953) Post-Cretaceous age travertine, Suisun, California (Craig, 1953) Stalactite, Blue Mounds Cave, Wisconsin (Craig, 1953) Travertine, Great Salt Lake (Craig, 1953) Travertine, Silver Gate, Yellowstone National Park (Craig, 1953) Four calcareous tufas, Engadine springs (Baertschi, 1957 )t White carbonate precipitate, Pfafer spring (Baertschi, 1957)t Calcareous concretions in loam (Baertschi, 1957)t Calcareous onyx, Pueblo, Mexico (Baertschi, 1957)t 6 other freshwater deposits (Baertschi, 1957)t 7 loess samples (Vogel, 1959) ** Losskindel (Vogel, 1959)** 7 calcareous sinters and stalagmites (Vogel, 1959)** 5 water samples, Heidelberg region (Vogel, 1959)** 5 water samples, brown coal region near Cologne (Vogel, 1959)** Fossils and matrices from Upper Cretaceous of England (Urey et al., 1951) 8 brachiopods 11 oysters 6 belemnites 22 chalk matrices 9 Devonian age brachiopods from Australia, most of which have undergone post-depositional isotopic re-equilibration (Compston, 1960) Recrystallized and infilled portions of Devonian age fossils from Australia (Compston, 1960) 31 Permian age brachiopods from Australia, believed to be isotopically preserved (Compston, 1960) 9 Permian age crinoids from Australia, believed to have undergone post-depositional isotopic re-equilibration (Compston, 1960) Range -1.9 to +0.9 Av. -0.1 Range -2.4 to -1.0 Av. -1.8 Range -13.1 to -6.1 Av. -10.1 Range (-10.2 to -4.6)* Av. (-8.2)* Range (-1.6 to +1.6)* Av. (-0.3)* -0.3, -0.6 +9.8 +3.6 +3.4 -6.7 -8.9 -10.1 +5.9 Range +6.3 to +11.0 Av. +9.1 -15.8 -8.5 +3.2 Range -9.4 to -2.1 Av. -6.0 Range -4.4 to -0.6 Av. -2.5 -8.1 Range -9.2 to -6.5 Av. -8.2 5 Range -14.3 to -12.9 Av. -13.3 Range -17.6 to -14.1 Av. -15.6 Range +1.3 9 to +2.9 Q Range +0.7g to +2.8 4 Range +0.4 6 to +3.2 Range +0.7! to +2.82 Range -0.2 to +1.9 Av. +0.6 Range -4.1 to -0.3 Range -2.74 to +5.8 Av. +4.3 Range -17.0 to +4.7 22 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 TABLE 4 - continued , _13 . o , o C in /oo Belemnite, Gallovien age (Baertschi, 1957)t Crinoids from Carboniferous Devonian age limestone (Baertschi, 1957 )t Olenus truncatus, Upper Cambrian (Baertschi, 1957)+ Silurian age limestone, Gotland (Wickman and von Ubisch, 1951)* Matrix Older calcite crystals in vug Younger calcite crystals in vug 26 salt-dome calcite caprock samples (Feely and Kulp, 1957) 6 calcites from salt-dome caprocks (Thode et al., 1954)# Lacustrine Green River Formation (Silverman and Epstein, 1958) Limestones and fossils, mostly Australian (Jeffery et al., 1955) 9 Tertiary 4 Mesozoic 6 Upper Paleozoic 8 Devonian 14 Cambrian and Silurian 4 marine limestones, comparison of matrix with calcite veins (Baertschi, 1957)+ 6 samples Leadville Limestone, Mississippian age, Colorado (Engel et al., 1958) 19 nonmarine shells, sediments, and limestones, modern-Pennsylvania'n (Clayton and Degens, 1959) 4 modern and Pleistocene samples 5 Tertiary limestones and fossils 10 Pennsylvanian limestones 12 marine shells and limestones (l modern, 1 Devonian, rest Pennsylvanian) (Clayton and Degens, 1959) 20 samples of calcite present in small amounts in coal (Wickman, 1953)* 15 samples, reddish variety of Lower Ordovician Limbata Limestone, Sweden (Landergren, 1954)* 18 samples, gray variety of Limbata Limestone (Landergren, 1954)* 7 samples, Lower Ordovician age Planimbata Limestone, Sweden (Landergren, 1954)* 7 samples, Cambrian and Ordovician age bituminous limestone, Sweden (Landergren, 1954)* +0.3 +2.5 +0.7 +4.6 +2.5 +1.2 Range (-43.8 to Av. (-35.2)* Range -51.1 to Av. -41.8 ■23.9)* •30.9 +2.0 Range -8.1 to +1.7 Av. -5.6 Range -1.2 to +2.0 Av. +0.1 Range -12.7 to +2.1 Av. -1.6 Range -1.7 to +4.7 Av. +1.2 Range -2.9 to +2.0 Av. -0.8 Over-all Av. -1.5 -0.8, -4.8 +1.8, +1.3 +1.5, -0.3 +0.8, +0.4 Range -2.8 to +0.8 Av. -0.7 Range -17.69 to -2.59 Av. -6.66 Range -17.69 to -5.54 Av. -10.06 Range -6.74 to -2.82 Av. -5.23 Range -9.79 to -2.59 Av. -6.02 Range -3.96 to -0.16 Av. -1.54 Range -19.2 to +8.3 Av. -2.9 Range -1.0 to +1.8 Av. +0.3 Range -6.7 to +0.4 Av. -1.8 Range -2.2 to +1.0 Av. -0.6 Range -4.2 to -1.0 Av. -2.6 GEOCHEMISTRY OF SEDIMENTARY CARBONATES - IV-A 23 TABLE 4 - continued 51 samples, Upper Ordovician age algal limestone, borehole, Gotland (Landergren, 1954)* Small amounts of carbonate in shales (Landergren, 1954)* 38 samples, alum shale 20 samples, Dictyonema shale 7 samples, various black shales Precambrian age dolomite (Baertschi, 1957)t Precambrian age algal limestone (Baertschi, 1957)+ 15 other limestones, Tertiary to Ordovician in age (Baertschi, 1957)+ 21 marine limestones, Cambrian to Pleistocene age (Craig, 1953) Spergen Limestone (Microcoquina ) , Mississippian age, Indiana Chalk, Cretaceous age, Dover, England Chalk, Cretaceous age, Mississippi Chalk, Cretaceous age, Colorado Randville Dolomite, Dickinson Co., Michigan, with algal structures Same without algal structures. * Stockholm results quoted in units of Cl2/cl3 have been converted to 6 C^ rela- tive to the Chicago PDB standard, using the relation (Harmon Craig, personal com- munication) 6 C 13= / 88^85 _ 6C 13 o , in /oo Range -1.0 to +3.9 Av. +0.7 Range -15.1 to -6.4 Av. -10.6 Range -12.4 to -6.0 Av. -9.0 Range -10.4 to +0.1 Av. -5.2 +8.0 +3.9 Range -0.8 to +2.8 Av. +1.3 Range -3.3 to +2.4 Av. -0.2 +2.4 +2.0 +1.4 +1.0 +1.1, +1.2 +1.1, +1.2 C12/C 13 ** Standard, "Solenhofen Limestone," is not defined further. + Reported by Baertschi as 6Cl3 relative to the Basel standard, and here recom- puted to 6 C-L3 relative to the Chicago standard using the relations given by Craig (1957b). $ Primary standard is "sedimentary limestone." # Reported by Thode et al. as the ratio of (C /C^^) sam pi e to that of the Chicago standard, 88.89, and here recomputed as 6 C^ relative to 88.99 for the Chicago standard (see Craig, 1957b). SELECTED CHEMICAL ANALYSES OF CARBONATE SEDIMENTS AND ROCKS Percentages given in parentheses are analytically determined quantities that are not included in the total because of duplication, for example, C0„ vs. loss on ignition ANALYSIS NUMBER (1) (2) (3) (4) (5) (6) Si0 2 18.8 8.21 58.6 52.8 Ti0 2 A1 2°3 Fe 2°3 18.8 8.21 0.3 0.14 5.1 4.14 1 4.09 >3. 8 1 0.4 0.54 39.0 44.55 1.4 0.83 FeO MnO 0.4 0.54 1.2 1.0 CaO 39.0 44.55 2.8 7.7 MgO 1.4 0.83 4.4 2.9 SrO BaO Na K 2 Li 2 2 5 CO 29.8 34.75 H 2 (-) H 2 (+) CI 0.31 S0 3 Zr0 2 0.08 S 0.09 Mn0 2 1.21 0.5 1.32 0.7 0.78 0.2 0.26 !9.8 34.75 54.48 5.19 0.98 0.06 15.94 0.81 8.66 0.84 f0.54 0.05 1.96 42.61 3.31 7.90 0.056 None 0.20 None 2.05 0.05 2.85 0.33 Trace 0.30 0.04 41.58 ri. 04 0.21 (110°C) 0.56* 0.02 0.05 Total 100.0 100.0 100.0 100.0 lOO.OOOt 100.09 (1) Average composition of calcareous sands and oozes, on a water-free basis (Poldervaart, 1955, recalculated from unpublished averages of W. W. Rubey). (2) Average composition of Globiierlna oozes from 66 stations (Sujkowski, 1952), modified to include C0 2 . All CO2 is assumed to be combined with CaO, and the amount of noncarbonate CaO is fixed by assuming it has the same ratio to Ti0 2 as in analysis (5). (3) Analysis (l) recalculated to a CaCOo-free basis for comparison with analyses of red clay. All CO2 in (l) has been assumed to be combined with CaO. (4) Average composition of red clay on a water-free basis (Poldervaart, 1955, recalculated from unpublished averages of W. W. Rubey). (5) Composite analysis of 51 samples of red clay, computed on a CaC03 _ free basis. Analyst, George Steiger, U. S. Geol. Survey, with special determinations by W. F. Hillebrand and E. C. Sullivan (Clarke, 1924). t Total also includes 0.012% Cr 2 3 , 0.039% NiO + CoO, 0.035% V 2 3 , 0.001% As 2 3 , Trace M0O3, 0.024% CuO, 0.008% PbO, 0.005% ZnO. (6) Composite analysis, by H. N. Stokes, of 345 limestones (Clarke, 1924). * Includes organic matter. [24] GEOCHEMISTRY OF SEDIMENTARY CARBONATES - I V-A 25 ANALYSIS NUMBER (7) (8) (9) (10) (11) (12) (13) (14) Si0 2 16.98 8.40 19.24 26.67 0.6 0.48 3.03 fsand 7. no. \sol. Si0 2 0.25 A1 2 6.44 3.15 3.26 0.91 5.5 0.23 0.18 None Fe 1.40 3.75 1.09 0.64 3.0 0.29 0.31 0.21 MnO CaO 29.73 44.00 MgO 8.25 0.47 Na 2 0.28 K-O 0.14 P 2°5 C0 2 32.52 33.20 H 2 (-) H 2 ( + ) CI S0 3 Ign. loss 6.7 55.5 Org. matter 2.96 5.10 Insol. res. None N 0.03 As 2 3 0.012 Total 100.21 99.67 100.35 99.97 98.0 99.75 100.51 (7) Sediment from the Isar River, Germany, containing abundant material from glacial deposits; rich in carbonates, including dolomite (Sauer, 1938). (8) Alluvium, banks of Shoal Creek near Austin, Travis County, Texas. J. E. Stullken, analyst (Schoch, 1918). (9) Adobe soil, Salt Lake City, Utah. Analyst, L. G. Eakins, U. S. Geol. Survey (Clarke, 1924). (10) Adobe soil, Fort Wingate, N. M. Analyst, L. G. Eakins, U. S. Geol. Survey (Clarke, 1924). (11) Hikutavake rocky silt loam, Niue Island, South Pacific (Schofield, 1959), Dominion analyst. (12) Average of four limestone analyses, Niue Island, South Pacific (Schofield, 1959), Dominion analyst. *One of the four analyses gave P_0 , 0.08. (13) Oolite at Black Rock, Great Salt Lake. George Cronkheit, analyst. (Eardley, 1938). (14) Oolite, Everglades, Florida. W. C. Wheeler, analyst (Clarke, 1915). 26 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 (15) (16) (17) (18) (19) Range Average Si0 2 1.88 0.53 0.43-16.88 9.07 19.42 6.56 Ti0 2 A1 2 3 0.36 0.14 0.06- 2.15 0.85 1.21 1.71 Fe 2 3 0.27 0.96* 0.24- 2.43 0.93 0.25 0.63 MnO Trace CaO 52.89 51.87 30.82-51.61 42.75 28.61 23.94 MgO 0.76 1.10 1.11- 1.81 1.46 9.42 15.07 ANALYSIS NUMBER (17) Range Average 0.43-16.88 9.07 0.00- 0.13 0.05 0.06- 2.15 0.85 0.24- 2.43 0.93 0.10- 0.28 0.18 30.82-51.61 42.75 1.11- 1.81 1.46 0.03- 0.30 0.14 0.00- 0.39 0.16 0.02- 0.15 0.09 25.00-41.66 34.62 0.54- 2.78 1.39 0.40- 1.13 0.69 3.41-16.18+ 7.57 Na 2 0.10 0.03- 0.30 0.14 3.73 KJD 0.10 0.00- 0.39 P,-A, 0.06 2 5 NaCl 4.29 C0 2 42.30 25.00-41.66 34.62 32.50 H 2 (-) 0,97 H 2 (+) 1.22 S0 3 0.14 Org. matter 0.17* Ign. loss 43.73 CI 4.09 S 0.20 ■] .84 Total 99.89 99.49 99.79-100.40 99.95 98.14 100.61 (15) Pisolite deposited from hot springs, San Antonio, Texas. W. C. Wheeler, analyst (Wells, 1937). (16) Marl, Ore Lake, Michigan. E. C. Sullivan, analyst (Clarke, 1915). *Total Fe as Fe 2 0-. (17) Ranges and average values for 9 analyses of marls from Minnesota lakes (Goldich et al., 1959). + Total loss on ignition, minus CO- and HJD (-). (18) Dolomite-bearing lake sediment, South Australia, (Alderman and Skinner, 1957, Contains precipitated celesite (H. C. W. Skinner, personal communication). *Acid-insoluble organic matter as carbon. (19) Dolomite-bearing sediment, 12 feet below surface, Lake Eyre (Bonython, 1956; T. R. Frost, analyst). Quartz, kaolinite, dolomite, illite, palygorskite, and gypsum are identified in X-ray powder diagrams taken by Dr. K. Norrish and Mrs. L. Rogers. GEOCHEMISTRY OF SEDIMENTARY CARBONATES - I V-A 27 ANALYSIS NUMBER (20) (21) (22) (23) (24) (25) Si0 2 14.41 7.52t 0.25 1.81 Ti0 2 0.24 Trace Al 2.77 "] "] "] "1 0.32 Fe'o' 1.31 j 1 ' 26 * J 1 ' 77 J 1 ' 06 J ' 56 0.04 FeO 1.40 MnO 0.02 28.4 0.01 CaO 26.95 1.26 1.18 1.84 51.52 52.18 MgO 11.61 23.64 38.28 36.40 2.08 0.86 Na 2 0.82 0.61 K 0.77 0.10 P o t 0.13 0.07 2 5 CO 31.52 18.21 34.97 23.71 41.58 42.04 HO (-) 1.72 "] 1.06(105°C) "1 "1 0.22(l05°C) H 2 ( + ) 3.46 j 13 ' 65 15.41 J 20 ' 81 j 3 ' 19 CI 0.14 S0 3 0.51 S 0.11 Insol. res. 14.93 (2.53) Vol. matter (1.43) Ign. loss (43.37) FeS 2 0.32 Org. C 1.84 8.40 "Elements of organic matter" 1.33 Total 101.06 94.82 100.19 98.75 99.18 98.58 (20) Uniformly fine-grained bottom sediment, Biurl ju-Tiupinskij pool of Lake Balkhash (Zalmanson, 1951). (21) Sediment in Lake El 'ton (Vital, 1951). * R 2 ° 3 ' (22) Hydromagnesite (?) deposit, Bannock County, Idaho (Yale and Stone, 1923). t Insoluble + Si0 2 . (23) Hydromagnesite (?) spring deposit in and upon shale, near Phillips Springs, Chiles Valley, Napa Co., California. R. C. Wells, analyst (Wells, 1910). The insoluble material is mainly shale. (24) Coquina, Key West, Florida. F. W. Clarke, analyst (Clarke, 1924). (25) Shell sand, John O'Groats, Caithness, Scotland. A. Muir and H. G. M. Hardie, analysts (Geol. Survey Gt. Britain, 1956; Specimen No. SL-164). Contains (ppm ) Ba 20, Cr 5, Li 10, Sr 1500 (R. L. Mitchell, analyst). 28 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 ANALYSIS NUMBER (26) (27) (28) (29) (30) (31) A B C S10 2 0.22 0.20 17.0 19.44 10.73 0. ,08 10. 65 Si 8.1 Ti0 2 None 0.28 0.32 0.15 0, ,15 Trace Al 3.9 A1 2°3 Fe 2 3 0.21 0.06 >0.28 9.0 3.1 5.71 2.37 3.69 1.21 1, V ,16 ,68 2. jo. ,53 ,42 Fe Ti 5.0 1.06 FeO 0.80 J J MnO Trace 0.18 0.15 0.05 Mg 1.6 CaO 50.19 52.84 37.0 35.62 42.22 41, ,68 0, ,54 Ca 23.9 MgO 0.66 0.82 3.4 1.74 0.34 0, ,10 0, ,24 Na 1.5 SrO 0.63 0.82 0.12 K 0.71 BaO 0.024 Sr 0.093 Na 2 2.5 2.06 1.87 Ba 0.078 K 2 1.1 0.91 1.47 B 0.032 P 2°5 Trace 0.06 0.22 Mn 0.12 co 2 40.60 41.60 33.9* (27.52) 21.72 Ga 0.0013 H 2 (-) H 2 (+) Org. Matter 0.79 1 (1.35) Ni 0.009 1 f 0.24 J 12.06 Cu 0.008 ^5.86 ' 0.16* (0.70) 0.03 Co 0.001 so 3 0.51 0.29t 0.30 0.43 Cr 0.019 Ign. loss 31.74 V 0.041 N (0.03) Zr 0.010 CI (1.84)** NaCl 2.36 Total 99.73 97.25 107. 8# 100.42 99.25 (26) Calcareous bottom mud, Bahamas. E. T. Erickson, analyst (Wells, 1937). The organic content of Bahaman bottom mud, apparently not the same sample, as determined by Erickson is total organic C, 0.65%; N, 0.07%; P, 0.01%; stabilized organic C insoluble in acids, 0.19%; stabilized organic H insoluble in acids, 0.03%. (27) Calcareous sediments rich in Ealimeda debris, from 108-foot depth in Bikini lagoon. Analyst A. C. Vlisidis; flame photometer determination of SrO by W. W. Brannock (Emery et al., 1954). * Acid-insoluble organic, t Acid- soluble SO . (28) Foraminiferal lutite, top of core A179-4 at depth 2965 meters, 16° 36' N, 74° 48' W, off the SW coast of Haiti. 0-10 cm. C 14 date is 3950 ± 250 years (Rubin and Suess, 1955). R. G. Smalley, spectrographer (Ericson and Wollin, 1956a). i Loss on HCL-treatment; alkalimeter method. # Total includes 0.008% CuO, 0.18% VJX, 0.018% Cr.O., 0.06% B o o , 0.008% PbO. 2 5 2 3 2 3 (29) Top of core 6-A18, North Atlantic, 49° 03' 30" N, 32° 44' 30" W, contains 0.1 ppm Se (Edgington and Byers, 1942). **0ven-dry basis. Dried salts from sea water were not removed. (30) Globiierina ooze, Meteor station 304 (Correns, 1937), Brunger, analyst. (A) Whole sample; (B) Soluble after digestion for two hours in hot 20 percent HC1; (C) Insoluble residue. (31) Average chemical composition of Pacific core NH-9, 21° 41.2' N, 157° 28. 5 1 W, depth 3027 meters, Globiierina ooze containing abundant pyroclastic material (Goldberg and Arrhenius, 1958). GEOCHEMISTRY OF SEDIMENTARY CARBONATES - I V-A 29 ANALYSIS NUMBER (32) (33) (34) (35) (36) 8.40 1.31 Trace 46.83 3.54 0.48 0.22 Trace 0.12 Trace Trace 1.45 31.58 42.15 42.78 40.88 Si0 2 A1 2 3 Fe 2°3 MnO CaO MgO Na 2 K 2 Li 2 P 2°5 NaCl co 2 H 2 (-) H 2 (+) CI S0 3 Ign. loss Org. Matter Org. C Org. H Total 0.05 0.05 0.85 V0.06 0.13 54.15 55.34 0.87 0.26 0.18 5.87 0.92 f0.15 fl.37 fl.02* 0.07 0.14 0.28 0.32 1.82 0.04 0.30 0.02 100.64 99.92 100.27 100.03 100.24 (32) Limestone caprock, Pleistocene age, Lubbock, Lubbock County, Texas. J. E. Stullken, analyst (Schoch, 1918). (33) Caliche, Buliba-ha, Chiapas, Mexico; F. Roel, analyst (instituto Geologico Mexico, 1913). (34) Calcareous tufa, Mammoth Hot Springs, Yellowstone National Park. F. A. Gooch, analyst (Clarke, 1915). (35) Travertine from cavity near Pulsating Geyser, Mammoth Hot Springs, Yellow- stone National Park. J. E. Whitfield, analyst (Clarke, 1915). * Includes H of organic matter. (36) Calcareous tufa, main terrace, Redding Spring, Great Salt Lake Desert. Analyst, R. W. Woodward, (King, 1878, p. 502). 30 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 ANALYSIS NUMBER (37) (38) (39) (40) (41) (42) Si0 2 0.40 1.13 0.75 0.80 14.25 1.57 Ti0 2 0.03 0.40 A1 2°3 0.52 0.51 0.25 0.01 5.95 0.40 Fe 2 3 0.08 0.31 0.64 4.01 0.24 MnO 0.02 Fe 0.04 Trace CaO 54.70 55.07 52.30 55.10 37.35 53.54 MgO 0.60 0.52 2.14 0.44 1.79 1.02 Na 2 0.16 0.01 0.57 K 2 0.00 0.04 0.62 P 2°5 0.020 P 0.04 0.007 co 2 41.70 (42.57) 43.54 43.29 29.56 H 2 (-) H 2 (+) \ 1.16 0.06 (105°C) f 0.50 4.14 S 0.27* 0.02 0.97 0.007 S0 3 (0.05) 0.07 Ign. loss (43.00) 43.15 43.27 Org. Matter Trace MnCU 0.02 Total 98.43 100.80 100.20 99.76t 100.77 100.13. 4 (37) "Bedford oolitic limestone," Spergen Formation, Mississippian age, Bedford-Bloomington district, Indiana; oolites with foraminifera and small shell fragments as cores, frequently cross-bedded. Alice W. Epperson, analyst (Bur. Standards Tech. Paper 349, 1927; cited in Loughlin, 1930). * Total S. (38) Oolite of the Ste. Genevieve Formation, Mississippian age, Hardin County, Illinois. L. D. McVicker, analyst (Lamar, 1957). (39) Oolite with foraminiferal centers, upper Sarmatian (Tertiary) age, upper Ilz valley, eastern Styria, Austria (Hubl, 1942). (40) Fine-grained algal Curley Limestone, Utah (Proctor and Clark, 1956). tTotal includes 0.01% Cu, 0.01% Pb. (41) Rock consisting of fine-grained calcite particles coated by limonite, to- gether with an assemblage of foraminiferal and ostracodal tests indicating deposition in shallow water, perhaps brackish water (Hubl, 1942). (42) Average of ten analyses of channel samples of fine-grained, brackish water limestone, containing charophyte oogonia and ostracodes and made up of crusts like those produced by blue-green algae, Baum Member, Paluxy Forma- tion of Lower Cretaceous age, Ravia-Mannsville area, Oklahoma. T. E. Hamm and A. L. Burwell, analysts (Wayland and Ham, 1955). GEOCHEMISTRY OF SEDIMENTARY CARBONATES - IV-A 31 ANALYSIS NUMBER (43) (44) (45) (46) (47) (48) Si0 2 6.30 0.10 1.45 0.29 0.40 0.52 TiCU 0.05 0.04 0.03 A1J0 0.75 0.14 0.74 0.26 0.37 Trace Fe o 0_ 0.39 0.08 1 FeO j ' 45 MnO 0.05 0.04 0.005 0.013 Trace CaO 51.09 54.35 53.52 55.53 55.88 54.81 MgO 0.63 0.93 0.60 0.70 0.38 0.39 Na 2 0.07 0.12 K 2 0.13 0.16 P^CL 0.03 0.03 0.046 0.011 0.02 2 5 CCL 40.22 42.40 (43.6; 43. IE H 2 (-) 0.08 (105°C) 0.07 H 2 (+) Ign. loss (40.35) 43.92 (42.82) 43.23 43.35 SO 0.15 0.15 S Trace FeS 2 0.04 0.14 Insol. res. (7.98) (2.82) 0.26 0.37 0.11 0.24 0.005 0.013 55.53 55.88 0.70 0.38 0.07 0.02 0.046 0.011 43.42) (43.62) ■0.03 Total 99.83 99.56 99.75 100.41 100. 79„ 99.08 4 (43) Turbid fine-grained carbonate containing numerous pellet structures, and recrystallized along a diffuse network of channels to anhedral carbonate of 0.03-0.1 mm. grain size. Upper Old Red Sandstone Series, Devonian age, near Muirkirk, Ayr, Scotland. A. Muir and H. G. M. Hardie, analysts (Geol. Survey Gt. Britain, 1956; Specimen No. SL-170). Contains (ppm ) Ba 15, Cr. 15, Li 20, Pb 15, Sr 250 (R. L. Mitchell, analyst ). (44) Average of 8 analyses of reef, fine-grained to foraminiferal and crinoidal, in the Marble Falls Formation of Pennsylvanian age in Burnet County, Texas (Barnes, 1952). (45) Limestone, Oil Shale Group, Calciferous Sandstone Series, Carboniferous age, Waterbeck, Dumfries, Scotland. Compact limestone composed of fragments of shells, polyzoa, foraminifera, productid spines, Calcisphaera and ostracodes cemented by fine-grained calcite and recrystallized small organic fragments. A. Muir and H. G. M. Hardie, analysts (Geol. Survey Gt. Britain, 1956; Sample No. SL 143). Contains (ppm ) Ba 10, Li 26, Sr 200, V 20 (R. L. Mitchell, analyst). (46) Crinoidal and bryozoan fragments in a matrix of broken fronds of fenestellid bryozoa, Salem Formation, Mississippian age, Union County, Illinois. L. D. McVicker, analyst (Lamar, 1957). (47) Lithographic limestone, St. Louis Formation, Mississippian age, Madison County, Illinois. L. D. McVicker, analyst (Lamar, 1957). (48) Dense subcrystalline, conchoidally fracturing Mosheim Limestone of the Middle Stones River Group of Ordovician age, Pendleton Co., West Virginia (McCue et al., 1939). 32 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 ANALYSIS NUMBER (49^ (50) (51) (52) (53J (54) 1.15 20.01 12.91 21.61 8.40 39.44 0.20 0.15 0.70 1.01 1.15 0.86 0.11 0.09 0.02 0.01 53.80 36.47 46.82 40.88 49.21 31.48 0.56 5.51 1.09 0.88 0.25 0.08 Si0 2 Ti0 2 A1 2 3 Fe 2°3 FeO MnO CaO MgO SrO Na 2 K 2 P 2°5 co 2 H 2 (- ■) H 2 ( + ) so 3 S FeS 2 Ign. ] .OSS Insol. res Tot; il (49) Litfo 0.07 20.01 12.91 21.61 0.08 1.23 0.98 1.51 0.76 0.43 1.23 0.012 0.02 0.06 36.47 46.82 40.88 5.51 1.09 0.88 0.044 0.09 0.07 0.20 0.28 0.083 0.17 0.07 34.18) 37.20 32.57 0.50 0.21 0.29 0.11 0.20 0.58 0.65 42.69 (34.18) 37.20 32.57 37.95 23.73 0.23 "1 0.50 (105°C) 0.14 0.17 0.69 7-0.10 0<89 1>?4 None 0.78 0.06 0.01 34.70 (33.00) (23.99) 99.90 99.88 9 99.78 99.76 99.92 99.90 Lithographic limestone, Solenhofen, Bavaria. Analysis by G. Steiger (Clarke, 1924). '50) Kinkaid Limestone, late Mississippian age, Johnson Co., Illinois. L. D. McVicker, analyst (Illinois Geol. Survey files). Finely disseminated, largely replacive silica, welded in considerable part into a coherent frame- work; carbonate matrix is mostly fine-grained, with some skeletal debris. (51) Arenaceous crinoidal Coeymans Limestone of Devonian age, Pendleton County, West Virginia (McCue et al., 1939). (52) Calmy Limestone, Carboniferous Limestone Series, near New Cumnock, Ayr, Scotland. Compact greenish-gray limestone composed of 0.02-0.03 mm grains of calcite and finer grained turbid interstitial siliceous material, with sporadic crinoid columnals and shell fragments. A. Muir and H. G. M. Hardie, analysts (Geol. Survey Gt. Britain, 1956; sample SL-92). Contains (ppm ) Ba 25, Cr 10, Li 15, Ni 10, Rb 30, Sr 500, Zr 15 (R. L. Mitchell, analyst). (53) Silty limestone, La Caja Formation, late Jurassic age, Zacatecas, Mexico. Analyst, Alberto Obregon (Rogers et al., 1956). (54) "Highly calcareous siltstone," La Caja Formation, late Jurassic age, Zacatecas, Mexico. Analyst, Alberto Obregon (Rogers et al., 1956). GEOCHEMISTRY OF SEDIMENTARY CARBONATES - IV-A 33 ANALYSIS NUMBER (55) (56) (57) (58) (59) (60) sio 2 12.65 26.33 36.65 38.00 55.90 55.42 Ti0 2 0.00 0.05 1.23 0.20 A1 2°3 0.82 0.91+2. 12* 25.22 19.92 22.17 Fe 2°3 0.66 0.82 17.53 7.30 8.30 FeO 0.91 7.54t 0.27 0.39 Trace MnO 0.00 0.06 Trace CaO 46.97 39.45 39.50t 2.07 0.50 0.15 MgO 0.56 0.95 7.23+ 1.31 1.18 1.45 SrO 0.00 Na 2 0.00 0.15 0.58 0.23 0.17 K 2 0.00 0.27 0.03 2.99 4.79 2.32 P 2°5 0.00 0.02 3.90* Trace 0.10 co 2 (37.85) 30.85 2.35 0.38 H 2 (-) H 2 (+) (105' >C) 0.48 1 2.41 2.54 2.10 > 0.62 7.04 6.52 7.76 Ign. loss 38.60 (30.50) -/ S 0.00 Insol. res. (27.78) FeS 2 0.04 C (0.38) N 0.00 Total 99.69 100.13 99.32 101.00 99.95 99.84 (55) Black siliceous concretions in Onondaga Limestone (Schwartz and Mathiasen, 1934). (56) Subrounded quartz grains frequently secondarily enlarged with a low propor- tion of alkali-feldspar grains, cemented by large amounts of calcite. Upper Old Red Sandstone, Devonian age, Benarty Hill, Fife, Scotland. A. Muir and H. G. M. Hardie, analysts (Geol. Survey Gt. Britain, 1956; sample SL-104). Contains (ppm) Ba 100, Cr 10, Li 8, Sr 500, V 30, Zr 20 (R. L. Mitchell, analyst ). (57) Greenish "sandstone" with abundant carbonate and phosphate cement, Lohne, Westphalia (von der Marck, 1855). * Insoluble and soluble A1~0„, respective- ly. + As carbonate. % As Ca (P0.)„. (58) Red earth cave sediment, residue from weathering of Schockekalke of Triassic age, near Weiz, Styria, Austria (Hubl , 1941). (59) Residual clay from limestone, Staunton, Virginia. George Steiger, U. S. Geol. Survey, analyst (Clarke, 1924). (60) Residual clay from Knox Dolomite, Morrisville, Alabama. Analyst, W. F. Hillebrand (Russell, 1889b). 34 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 ANALYSIS NUMBER (61) (62) (63) (64) Sol. in Insol. 2% HCl 2% HCl in Insol. % Computed Insol.* % Si0 2 14.11 0.07 4.34 54.2 56.2 25.05 19.10 Ti0 2 0.16 Trace A1 2°3 4.16 0.06 1.69 21.1 17.5 8.28 2.86 Fe 2 3 1.63 0.0 0.38 4.8 4.9 0.27 7.04 FeO 0.28 0.01 0.1 0.6 2.41 MnO 0.038 0.02 4.11 CaO 41.32 50.2 0.06 0.73 0.7 27.87 35.80 MgO 2.19 0.76 0.21 2.65 3.0 2.61 1.60 SrO 0.12 Na 2 0.39 0.03 0.05 0.66 0.65 K 2 0.71 0.06 0.39 4.9 4.5 2.05 P 2°5 0.15 0.15 0.08 0.20 co 2 33.53 40.3 24.20 30.20 H 2 (-) H 2 (+) 0.36 0.5 4.5 6.3 5.1 6.1 1.44 2.86 pi. 10 CI 0.03 0.30 S0 3 0.04 Trace Ign. loss (34.55) S 0.25 MnO 0.05 C 0.61 Total 99.40 o 92.0 8.0 99.18 100.30 (61) Argillaceous limestone, U. S. National Bureau of Standards sample la, dried at 105°C. (Nat'l Bur. Standards, 1954). (62) Argillaceous Wellenkalk of the mu, zone, Muschelkalk (Middle Triassic), Plesse, West Germany, formed in an epicontinental sea apparently below wave base (Fuchtbauer, 1950; personal communication). *Insoluble residue estima- ted from microscopic examination to contain 14.2% quartz, 5% plagioclase, 5.6% orthoclase, 75.2% illite. (63) Highly calcareous Cretaceous age "shale," Mount Diablo, Calif. W. H. Melville, U. S. Geol. Survey, analyst (Clarke, 1924). (64) Glauconitic limestone containing glauconite and quartz grains, molluscan, echinodermal, and foraminif eral remains, and fine-grained calcite cement; Lutetian (Eocene) age, from Conflans-Saint-Honorine (Seine-et-Oise) (Cayeux, 1935). GEOCHEMISTRY OF SEDIMENTARY CARBONATES - IV-A 35 ANALYSIS NUMBER (65) (66J (67) (68) (69j (70) Si0 2 9.20 4.54 13.4 17.7 5.10 Ti0 2 0.13 0.1 A1 2 7.48 0.94 2.73 2.5 0.64 3.78 Fe 2 3 1.44 4.65 1.1 0.24 0.32 Fe0 )l5.31 MnO J 0.20 0.06 CaO 29.51 47.84 55.7+ 29.9 50.25 36.34 MgO 6.30 17. 4t 9.9 10.04 Na 2 0.8 K 2 0.9 P o R 4.21 9.16 9.2 2.6 5.1 2 5 C0 2 29.80 (25.9) 30.3 35.18 (33.11) HO (-) ~] 0.08 (100°C) "1 H 2 0( + ) ) 3 ' 10 * j ' 6 (0.52)** S0 3 0.77 1.0 9.72 Ign. loss 29.90 (33.8) Total S 1.41 Carbonaceous material 2.9 "P. P. P." 34.27 Acid insol. F V 2°5 Org. oxygen 6.9 0.3 0.50 0.1 0.01 (0.46) 100.7 99.63 Analyst J . E. Stullk. sn (Schoch, Total 99.38 100.20 104.8 (65) Greensand of Eocene age, Palestine, Texas. 1918).* HO plus organic. (66) Phosphatic Cornishville horizon of the Perryville Limestone of Ordovician age, Harrodsville, Kentucky (Foerste, 1913). (67) Fossilif erous crystalline limestone of the Sellersburg Formation, Devonian age, Clark Co., Indiana, containing abundant phosphate nodules (Murray, 1955). + CaCO . * MgCO . R. K. Leininger, spectrographer. Total S, P 2 ° 5 » and C° 2 chemically determined, under direction of M. E. Coller. (68) Average chemical composition of 15 carbonate rocks of the Meade Peak Member of the Phosphoria Formation, Permian age, Coal Canyon, Wyoming (Gulbrand- sen, 1958, compiled from McKelvey et al., 1953). (69) Phosphatic limestone of the La Caja Formation, Jurassic age, Zacatecas, Mexico. Analysts, Guttag, Caemmerer, Barlow, Rowe and Tucker (Rogers et al., 1956). Highly variable amounts of phosphate pellets and replacements of radiolaria, in finely crystalline, strongly fetid calcite matrix, together with a little chert and detrital quartz. (70) Anhydrite-containing dolomite of lower Tertiary age, southeast Ferghana USSR; a shallow-basin deposit. Analysis computes to 46% dolomite, 2b% calcite, \b^% anhydrite, 9% terrigenous detritus (Osipova, 1949). **Hydrate water. 36 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 ANALYSIS NUMBER (71) (72) (73) (74) (75) (76) (77) (78) A B C sio 2 2. 11 25.91 21 .9 ** 8.6 5.23 0.89 39.92 0.0 3.77 Ti0 2 0. ,028 0.18 0.42 0.02 0.03 A1 2°3 0. ,38 3.87 6.4+t 4.6 0.29 0.20 8.76 2.7 0.78 Fe 2 3 FeO 0. ,32 0.89 0.73 2.3** 2.6** 0.61 0.04 0.41 14. 4l) l.OlJ 23 ' 9 2.20 MnO 0. ,20 0.08 0.00 0.16 0.15 CaO 93. ,8* 17.89 21.2** 21.2 50.75 53.28 15.68 93.4 44.36 MgO 1, ,85* 10.44 8.4** 3.9 0.75 0.54 0.08 96.7 6.03 BaO 0.00 Na 2 K 2 5.57 1.0 0.42 0.08 " 1 1 1 0.06 2.69 1.3 0.93 0.08 >-0.07 M.56>51.5 0.13 Li 2 0.04 * • J P 2°5 0, ,066 (<1) 0.04 0.44 0.11 0.04 co 2 19.98 26.49 25.72 40.47 42.63 9.52 95.1 41.51 H 2 (-) H 2 (+) 3.54 2.09 0.15 0.25 2.13 0.32 ;i05°C) (105 °C) Total S 1. ,1 16.71 so 3 . (8.2) 0.00 0.5 Cl 0.21 Org. C 2.29 8.46 Org. H 0.31 1.21 N 0.04 0.29 S 0.39 0.25 (1.2) 0.00* Org. matter (2.64)0- 2.23 FeS 2 0.23 0.59 Vol. matter (0.61) 0.43P 7.94? 61. C ) Ign. loss 55.3 (41.23) (40.81) Insol. res. (6.08) (5.33) Ash 55.05# Total 99, ,85 100.05 99.91 98.93 99.41 98.93 98.49 98.88 99.90 (71) Coarse-grained fossiliferous limestone of Harrodsburg Formation, Mississip- pian age, Lawrence Co., Indiana, containing dark brown lenses and masses of gypsum throughout (Perry et al., 1954). *CaC0„. tMgCO^. R. K. Leininger, spectrographer. Total S and P 9 0^ chemically aeterminea. GEOCHEMISTRY OF SEDIMENTARY CARBONATES - IV-A 37 (72) Gypsiferous pyritic limestone of the Greenhorn Formation, Upper Cretaceous age, Black Hills area. Analyst, J. G. Fairchild (Rubey, 1930). * Oxygen calculated by difference, probably a minimum value. # Ash minus CO2 and SO3 found in the ash. a H+C+N+0, probably a minimum value. The analysis com- putes to 45.4% calcite, based upon the CO2 value, about 25.2% pyrite, 17.6% gypsum, <6.1% Fe oxides as limonite, >2.6% organic matter, about 2.0% bone phosphate, and 1.1% moisture. There is 0.03% chloroform-soluble material. (73) "Oil shale," Green River Formation, Eocene age. John Hay, Jr., Well No. 1, Sweetwater County, Wyoming, J. J. Fahey, analyst (Unpublished data, U. S. Geol. Survey). Na20 and lOpO determined by Laura Reichen using ion exchange method. Li 2 determined by Janet Fletcher by means of visible spectrum. Total includes 0.15 percent subtracted as oxygen correction for CI and S, the S correction being made on the basis of the S present as pyrite. Spec- trographs analysis by Janet D. Fletcher gives (ppm): Cu 380, Pb 20, Mn 500, Ni 20, Cr 30, V 60, Sc 2, Ti 90, Zr 30, Sr 900, Ba 500, B 70. (74) Bed "J", Mahogany Ledge, Green River Formation, Eocene age, Rifle, Colorado (compiled from Stanfield et al., 1951). Consists principally of calcite, dolomite, illite, and kerogen. ** Ash composition calculated to raw-shale basis, tt (R20 3 -Fe 2 3 ). (75) Bituminous stylolite filling in reef limestone of Pennsylvanian-Early Permian age, Horseshoe Atoll, West Texas. Analysis by U. S. Geol. Survey (Myers et al., 1956). *4 Total Fe as Fe 2 3 . (76) Burdiehouse Limestone, Oil Shale Group, Calciferous Sandstone Series, Car- boniferous age, near Harburnhead, Midlothian, Scotland. Minutely granular calcite permeated by films of yellow bituminous matter, containing numerous ostracode shells and lesser amounts of pyrite, fossil phosphate, and (?) celestite. A Muir and H. G. M. Hardie, analysts (Geol. Survey Gt. Britain, 1956; Sample SL-54). Contains (ppm) Ba 200, Li 3, Sr 1000 (R. L. Mitchell, analyst ). (77) (A) Buff Salem Limestone, Mississippian age, (B) Residual clay of associated stylolite seam, (c) Percentage of each constituent lost in going from (A) to (B) (Stockdale, 1922). K. W. Ray, analyst. P Volatile and combustible matter, less CO2. (78) Limestone, Cementstone Group, Calciferous Sandstone Series, Carboniferous age, near Riccarton Junction, Roxburgh, Scotland. Large fairly thin-walled shells in calcite mudstone showing a pellet-like structure and containing shell fragments coated with oolitic carbonate as well as fragments of shelly calcite mudstone, the whole in places partly recrystallized and dolomitized. A. Muir and H. G. M. Hardie, analysts (Geol. Survey Gt. Britain, 1956; Sample No. SL-200). Contains (ppm) Ba 15, Cr 5, Li 30, Rb 30, Sr 250 (R. L. Mitchell, analyst). 38 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 ANALYSIS NUMBER (79) (80) (81) (82) (83) (84) Si0 2 0.06 15.40 0.31 0.41 32.28 0.49 Ti0 2 0.00 0.20 0.005 A1 2 3 0.25 4.00 0.067 0.177 4.88 0.50 Fe 2°3 0.02 0.58 0.084 0.157* 1.13 0.29 FeO 0.07 0.98 1.52 MnO 0.006 0.33 CaO 30.57 24.47 30.49 30.71 18.68 21.73 MgO 21.54 16.77 21.48 21.18 11.66 13.61 SrO <0.01 Na 2 0.11 0.06 0.08 0.029 0.15 K 2 0.01 0.69 0.03 0.051 3.01 P 2°5 0.003 0.004 0.62 co 2 (47.12) 36.32 47.25 31.45 H 2 (■ ■) 0.11(105°C) 0.21(105°C) 0.09(105°C) H 2 (■ 0.70 S0 3 0.16 0.035 0.031 Ign. ; Loss 47.74 (36.88) (47.52) 47.26 (105-950°C) 27.93 S 0.26 0.013 Insol, , res. (28.96) C 0.08 H 2 il 0.008 Tot; 100.37 99.89 99.94 100. 21 g 99.72 100.29 (79) Doli Dmitized reef- -core, R acine Formation, Silurian age, Cook County, Illinoi Ana Lyst, L. D. McVicker (Willmanj , 1943). (80) Arg illaceous off- -reef do lomite, Niagaran Formation, Siluriar i age, Cook County, Illinois. Analyst, L. D. McVicker (Lamar, 1957). (81) Dolomite, U. S. National Bureau of Standards sample 88, dried at 105°C. (Nat'l Bur. Standards, 1954). (82) Dolomite of the Royer Formation, Cambrian age, Johnson County, Oklahoma, believed from textural and field relations to be a replacement of a highly pure marine limestone; cavities in outcrop samples such as this contain secondary calcite encrustations, not seen in quarry faces of fresh rock. A. C. Shead, analyst (Ham, 1949). Total Fe as Fe 2 . (83) Dolomite of the Honey Creek Formation, Cambrian age,. Johnson County, Okla- homa, a sparingly fossilif erous marine unit containing brachiopod and trilobite fragments in some beds. Insoluble residue: typically 60% feldspar, 35% quartz, ~1% zircon and sericite, all detrital from a Precambrian area to the west, plus 1 to 15% glauconite. A. C. Shead, analyst (Ham, 1949). (84) Fine-grained dolomite containing echinoidal and brachiopod fragments, angular to subangular quartz grains and streaks of chert, and accessory oolitic carbonate grains. Lower Cambrian age, near Chrudaidh, Kyle of Durness, Sutherland, Scotland (Geol. Survey Gt. Britain, 1956; Specimen No. M-2926). A. Muir and H. G. M. Hardie, analysts. GEOCHEMISTRY OF SEDIMENTARY CARBONATES - IV-A 39 ANALYSIS NUMBER (85) (86) (87) (88) (89) (90) Si0 2 30.46 0.58 16.63 13.71 11.65 Ti0 2 0.40 0.21 0.01 A1 2°3 Fe 2°3 6.86 4.53 f0.37 7.43 0.28 4.23 1.19 1.18 0.25 f 4.38* FeO 1.89 6.03* 2.79 MnO 0.24 0.23 CaO 16.02 25.18 21.62 27.41 4.87 4.62 MgO 10.07 18.11 10.20 12.20 37.66 35.40 SrO 7.86 BaO 0.13 0.00 Na 2 0.38 0.11 0.14 0.23 0.31 0.63 K 2 5.77 0.05 0.75 0.94 0.32 1.36 Li 2 Trace 0.22 P 2°5 0.02 0.25 0.15 co 2 22.55 39.55 31.10 35.15 40.09 H 2 ( H 2 ( + ) > 1.42 0. 67(105 °C) 2.61t 0.37 2.15 1.82 CI 0.04 Trace 0.65 S0 3 6.33 0.06 0.12 7.32 B 2°3 None Org. Matter 0.92 H 2 S Trace Ign. loss (36.81) Vol. matter (1.3) Insol . res. (19.76) FeS 2 1.49 0.03 C 0.64 "P.P. P." 35.22 "Unde t. res." al 6.16 Tot 99.95 99.25 100.54 98.84 100.65 95.74 (85) Unmet amorphosed southern Alberta potash feldspar dolomite i, contair crystals of the Waterton ling some 40% by (Daly, 1917). Fc vc irmation, ilume of Precambrian disseminated age, authigenic (86) Celestit e-bearir ig dolomit ;e of the Salina Fc irmation, Silurian age, Maybee, Michigan (Kraus and Hunt, 1906). The alkaline earth precipitates were checked spectrographically to verify the separation of Ca and Sr. 40 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 (87) Ferroan dolomitic siltstone, Middle Coal Measures, Woodborough bore hole; tough, dark gray, unbedded rock consisting of an aggregate of 5-10(i car- bonate rhombs having nQ = 1.680-1.705, with tiny, angular grains of quartz and clay minerals, small pyrite streaks, a little collophane, and coloring from carbonaceous ma'terial. G. A. Sergeant, analyst (Edwards and Stubble- field, 1948). * Approximate because of presence of organic matter, t In- cludes any HoO derived from organic matter. (88) Compact gray rock composed mainly of grains of carbonate 0.005-0.01 mm across having refractive indices of ferroan dolomite, together with slightly larger grains up to 0.02 mm much altered to limonite (probably were siderite). Cementstone Group, Calciferous Sandstone Series, Carboniferous age, near Mid Calder, Midlothian, Scotland. A. Muir and H. G. M. Hardie, analysts (Geol. Survey Gt. Britain, 1956) Specimen No. SL-181). Contains (ppm) Ba 2000, Co 15, Cr 30, Ga 5, La 30, Ni 30, Rb 300, Sr 200, V 60, Y 30, Zn 60 (R. L. Mitchell, analyst). (89) Magnesite bed, Horse Spring Formation, Overton, Nevada. Charles Milton, analyst (Wells, 1937). An analysis of material from the same deposit by R. C. Wells (Wells, 1937) is very similar. (90) Sedimentary magnesite rock of early Permian age, Western Urals (Frolova, 1955). *R 2 3 . GEOCHEMISTRY OF SEDIMENTARY CARBONATES - IV-A 41 ANALYSIS NUMBER (91) (92) (93) (94) Insolubl e Wat ;er- Acid- Acid- in water so] .ubl e soluble insoluble Si0 2 0.0 0.39 18.24 2.10 Ti0 2 None 0.28 A1 2°3 None 5.90 2.82 Fe 2°3 0.08 None 1.22 36.60* 24.00 FeO 9.02 42.10 3.62 MnO 0.12 0.61 1.12 CaO 0.0 0.24 0.75 0.87t 33.85 MgO 25.94 1.23 0.35 6.10* 1.22 SrO BaO Na 2 (Na) 12. 41 K 2 (K) 0. 06 Li 2 (Li) 0. 09 P 2°5 0.33 0.34 co 2 33.29 C0 3 57.03 30.30 H 2 (-) H 2 (+) fO.O f 0.58 CI 19. 06 S0 3 None S 0.44 0.22 "P. P. P." 24.31 Total 100 .07 6 9.79 27.18 100.60 99.59 (91) Magnesite-halite rock, Unterbreizbach salt mine, Rhon region, Germany (Hartwig, 1955). (92) Siderite-bearing bed, Devonian age, western Bashkiria. B. V. Bal'shina, analyst (Florenskij and Bal'shina, 1948). (93) Caprock of Carlos Dome, Grimes Co., Texas, 3770-3780 foot interval in core. F. W. Jessen, analyst (Rolshausen, 1934). *Fe. tCa. *Mg. (94) Frodingham ironstone, Type D, of Mesozoic age; hard, calcite-cemented shell- rich limestone containing reworked oolites of chamosite largely replaced by limonite. Dried at 105°C. Analyzed by the Ore-mining Branch of United Steel Cos. (Taylor et al., 1952). Computes to about 28% limonite, 8% siderite, 5% chamosite, and 58% calcite.) 42 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 308 ANALYSIS NUMBER (9b) (96) (97) (98) 7.24 6.11 3.36 3.21 35.53* 11.30 2.30 Si0 2 8.7 4.7 15.33 Ti0 2 0.67 A1 2°3 8.3 4.4 11.56 Fe 2°3 10.3 1.2 1.71 FeO 36.0 47.2 7.83 MnO 0.2 0.3 34.46 CaO 5.3 4.7 2.29 MgO 3.8 2.6 3.37 BaO 0.07 Na 2 0.46 K 2 1.18 P 2°5 2.0 0.4 Nil co 2 (22.2) (32.9) 20.60 H 2 (-) 0.54 H 2 ( + ) 0.15 S (0.24) (0.11) Trace Ign. loss 25.3 34.1 Total 99.9 99.6 100.22 100.09 (95) Northampton sand ironstone; chamosite oolites, partly replaced by limonite set in 0.03-0.2 mm grains of siderite formed by partial recrystallization of a finer grained siderite mud. Dried at 100°C, average of 4 analyses (Taylor, 1949). Computes to about 55% siderite and 27% chamosite. (96) Northampton sand ironstone; compact fine-grained rock composed of over siderite, together with some quartz. Dried at 100°C, average of 2 analyses (Taylor, 1949). (97) Mn-rich carbonate bed of early Cambrian age, St. Tudwal's, North Wales (Mohr, 1956). (98) Mn-rich beds, Green Band, Manuels, Newfoundland (Dale, 1915). * Includes 8.08% Mn0 2 . Illinois State Geological Survey Circular 308 42 p., 4 tables, 98 analyses, 1960 CIRCULAR 308 ILLINOIS STATE GEOLOGICAL SURVEY URBAN A ^jjgfo 166