Hypostratotype of the Bashkirian Stage of the Carboniferous System (Askyn River, Bashkortostan): Lithology, Isotopes (δ13C, δ18O), and Carbonate Depositional Settings
Abstract—
The isotopic composition and lithology of the hypostratotype of the Bashkirian Stage (Pennsylvanian) in the Askyn River section (Bashkortostan, western slope of the South Urals) are studied. The isotopic study (δ13C, δ18O) was conducted taking the carbonate lithology into account. The succession studied is composed of Upper Serpukhovian, Bashkirian, and Lower Moscovian carbonates of various lithological types, changeable throughout the section. The Serpukhovian carbonates are characterized by a relatively light carbon isotopic composition (negative values of δ13C), whereas the Bashkirian and Moscovian sediments have a heavy composition (mainly positive values of δ13C). The carbon isotope anomaly of the first order, fixed at the Mississippian–Pennsylvanian boundary and having a global distribution, is recorded in the studied hypostratotype section slightly higher than the uniformly accepted boundary level. This may indicate that the section contains “transitional beds” at the base of the Bashkirian. In the studied carbonates, a dependence (of the second order) of the isotopic composition of carbon and oxygen on the lithological type of rocks is sometimes recorded. The variation in the values of δ13C and δ18O in carbonates reflects changes in the conditions in which they were formed (temporary and local changes in paleotemperature, bioproductivity, desalination) and epigenetic changes.
Keywords:
isotopic composition carbon oxygen carbonates hypostratotype Bashkirian Stage chemostratigraphy AskynNotes
ACKNOWLEDGMENTS
This study was carried out within a framework of State Contract no. 0135-2016-0017 “Isotopic and Geochemical Indicators of the Age and Origin of Chemostratigraphic Markers and Stages in Lithogenesis in Sedimentary Late Precambrian and Phanerozoic Series,” State Contract no. 0252-2014-008 “Isotopic and Geochemical Reconstructions of Paleogeographical Settings of the South Urals at the Riphean–Vendian Boundary,” and State Contract no. 0252-2014-0002 “Geological Evolution of the Uralides of the South Urals at the Orogenic Stage.”
REFERENCES
- 1.Alekseev, A.S., Typification of Phanerozoic mass extinction events, Moscow Univ. Geol. Bull., 2000, no. 5, pp. 6–14.Google Scholar
- 2.Alekseev, A.S., Revision of general scale of the Carboniferous system, Litosfera, 2003, no. 1, pp. 3–12.Google Scholar
- 3.Batt, L.S., Montanez, I.P., Pope, M.C., et al., Multi-carbonate component reconstruction of mid-Carboniferous (Chesterian) seawater δ13C, Palaeogeogr., Palaeoclimatol., Palaeoecol., 2007, vol. 256, pp. 298–318.CrossRefGoogle Scholar
- 4.Berner, R.A., A model of atmospheric CO2 over Phanerozoic time, Am. J. Sci., 1991, vol. 291, pp. 339–376.CrossRefGoogle Scholar
- 5.Berner, R.A., 3GEOCARB II: A revised model of atmospheric CO2 over Phanerozoic time, Am. J. Sci., 1994, vol. 294, pp. 56–91.CrossRefGoogle Scholar
- 6.Biostratigraphy of deposits of the Bashkirian Stage of the Volgo-Ural Region, in Tr. VNIGNI. Vyp. 107 (Trans. All-Russ. Res. Geol. Oil Inst. Vol. 107), Moscow: Nauka, 1971.Google Scholar
- 7.Botz, R., Stofter, S.P., Faber, E., and Tietz, K., Isotope geochemistry of carbonate sediments from Lake Kivu (Eastern-Central Africa), Chem. Geol., 1988, vol. 69, pp. 299–308.CrossRefGoogle Scholar
- 8.Brand, U. and Bruckschen, P., Correlation of the Askyn River section, Southern Urals, Russia, with the Mid-Carboniferous Boundary GSSP, Bird Spring Formation, Arrow Canyon, Nevada, USA: implications for global paleoceanography, Palaeogeogr., Palaeoclimatol., Palaeoecol., 2002, vol. 184, pp. 177–193.CrossRefGoogle Scholar
- 9.Brand, U., Jiang, G., Azmy, K., et al., Diagenetic evaluation of a Pennsylvanian carbonate succession (Bird Spring Formation, Arrow Canyon, Nevada, U.S.A.) – 1: Brachiopod and whole rock comparison, Chem. Geol., 2012, vols. 308–309, pp. 26–39.CrossRefGoogle Scholar
- 10.Brasier, M.D., Shields, G.S., Kuleshov, V.N., and Zhegallo, E.A., Integrated chemo- and biostratigraphic calibration of early animal evolution: Neoproterozoic–Cambrian of Southwest Mongolia, Geol. Mag., 1996, vol. 133, no. 2, pp. 445–485.CrossRefGoogle Scholar
- 11.Bruckschen, P., Oesmann, S., and Veizer, J., Isotope stratigraphy of the European Carboniferous. Proxy signals for ocean chemistry, climate and tectonic, Chem. Geol. Isotope Geosci. Sect., 1999, vol. 161, pp. 127–163.Google Scholar
- 12.Buggish, W., Wang, X., Alexeev, A.S., and Joachimski, M.M., Carboniferous–Permian carbon isotope stratigraphy of successions from China (Yangtze platform), USA (Kansas) and Russia (Moscow basin and Urals), Palaeogeogr., Palaeoclimatol., Palaeoecol., 2011, vol. 301, pp. 18–38.CrossRefGoogle Scholar
- 13.Chumakov, N.M., Glaciation of the Earth: history, stratigraphic significance and role in biosphere, in Tr. Geol. inst. Vyp. 611 (Trans. Geol. Inst. Russ. Acad. Sci. Vol. 611), Moscow: GEOS, 2015.Google Scholar
- 14.Egorov, A.I., Poyasa ugleobrazovaniya i neftegazonosnye zony zemnogo shara (Belts of Coal Formation and Petroleum Provinces of the World), Rostov-on-Don: Rostov. Gos. Univ., 1960 [in Russian].Google Scholar
- 15.Egorov, A.I., Global’naya evolyutsiya torfouglenakopleniya. Paleozoi (Global Evolution of Peat and Coal Accumulation: Paleozoic), Rostov-on-Don: Rostov. Gos. Univ., 1992 [in Russian].Google Scholar
- 16.Einor, O.L., Issledovaniya po stratigrafii karbona vostochnoi okrainy Uralo-Volzhskoi neftenosnoi oblasti (Gornaya Bashkiriya) (The Study of the Carboniferous Stratigraphy of the Eastern Margin of the Volga–Ural Petroleum Province (Mountainous Bashkiria)), Moscow: Gostoptekhizdat, 1958 [in Russian].Google Scholar
- 17.Einor, O.L., Problem of subdivision of the Bashkirian Stage in the stratotype area, Byull. MOIP. Otd. Geol., 1992, vol. 67, no. 2, pp. 67–79.Google Scholar
- 18.Friedman, J. and O’Neil, Y.R., Compilation of stable isotope fractionation factors of geochemical interest, US Geol. Surv. Prof. Pap., 1977, no. 440-KK, pp. 1–110.Google Scholar
- 19.Grossman, E.L., Zhang, C., and Yancey, T.E., Stable-isotope stratigraphy from brachiopods of Pennsylvanian shales in Texas, Bull. Geol. Soc. Am., 1991, vol. 103, pp. 953–965.CrossRefGoogle Scholar
- 20.Grossman, E.L., Mii, H.-S., and Yancey, T.E., Stable isotopes in Late Pennsylvanian brachiopods from the United States: implications for Carboniferous paleoceanography, Bull. Geol. Soc. Am., 1993, vol. 105, pp. 1284–1296.CrossRefGoogle Scholar
- 21.Grossman, E.L., Bruckschen, P., Mii, H.-S., et al., Carboniferous paleoclimate and global change: isotopic evidence from the Russian Platform, in Stratigrafiya i paleogeografiya karbona Evrazii (Carboniferous Stratigraphy and Paleogeography in Eurasia), Ekaterinburg: Inst. Geol. Geokhim. UrO RAN, 2002, pp. 61–71.Google Scholar
- 22.Grossman, E.L., Yancey, Th.E., Jones, Th.E., et al., Glaciation, aridification, and carbon sequestration in the Permo–Carboniferous: the isotopic record from low latitudes, Palaeogeogr., Palaeoclimatol., Palaeoecol., 2008, vol. 268, pp. 222–233.CrossRefGoogle Scholar
- 23.Groves J.R. Calcareous foraminifers from the Bashkirian stratotype (Middle Carboniferous, South Urals) and their significance for intercontinental correlation and the evolution of the Fusulinidae, J. Paleontol., 1988, vol. 62, no. 3, pp. 368–399.CrossRefGoogle Scholar
- 24.Groves, J.R., Nemirovskaja, T.I., and Alekseev, A., Correlation of the type Bashkirian Stage (Middle Carboniferous, South Urals) with the Morrowan and Atokan series of the Midcontinental and western United States, J. Paleontol., 1999, vol. 73, no. 3, pp. 529–539.CrossRefGoogle Scholar
- 25.Haq, B.U. and Schutter, S.R., A chronology of Paleozoic sea-level changes, Science, 2008, vol. 322, pp. 64–68.CrossRefGoogle Scholar
- 26.Kabanov, P.B., Micritization of particles as a facies indicator of the shallow-marine carbonate rocks, Byull. MOIP. Otd. Geol., 2000, vol. 75, no. 4, pp. 39–47.Google Scholar
- 27.Katz, D.A., Buoniconti, M.R., Montaez, I.P., et al., Timing and local perturbations to the carbon pool in the lower Mississippian Madison Limestone, Montana and Wyoming, Palaeogeogr., Palaeoclimatol., Palaeoecol., 2007, vol. 256, pp. 231–253.CrossRefGoogle Scholar
- 28.Kholodov, V.N., Kuleshov, V.N., and Nedumov, R.I., Catagenetic transformations and isotopic composition of carbonates in Tertiary deposits: evidence from Kuban Superdeep Boreholes (SGS-1 and SGS-2), Lithol. Miner. Resour., 1999, no. 1, pp. 46–57.Google Scholar
- 29.Kulagina, E.I., The Bashkirian–Moscovian boundary (Middle Carboniferous) in the Southern Urals in the light of the evolution of fusulinids, Byull. MOIP. Otd. Geol., 2008, vol. 83, no. 1, pp. 33–43.Google Scholar
- 30.Kulagina, E.I., Pazukhin, V.N., Kochetkova, N.M., et al., Stratotipicheskie i opornye razrezy bashkirskogo yarusa karbona Yuzhnogo Urala (Carboniferous Stratotype and Reference Sections of the Bashkirian Stage in the Southern Urals), Ufa: Gilem, 2001 [in Russian].Google Scholar
- 31.Kulagina, E.I., Pazukhin, V.N., Kochetkov, N.M., and Kochetova, N.N., Suggestions on improvement of stratigraphic scheme of the Bashkirian Stage, in Geol. Sb. no. 1 (Coll. Sci. Works in Geology. Vol. 1), Ufa: Inst. Geol. Ufim. Nauchn. Tsentr Ross. Akad. Nauk, 2000, pp. 64–65.Google Scholar
- 32.Kuleshov, V.N. and Sedaeva, K.M., Geochemistry of Isotopes (δ13S, δ18O) and Formation Conditions of Upper Kazanian Carbonate Rocks in the Volga–Vyatka Interfluve, Lithol. Miner. Resour., 2009, no. 5, pp. 495–510.Google Scholar
- 33.Kuleshov, V.N., Sedaeva, K.M., and Stroganova, Yu.Yu., Geochemistry of isotopes (δ13C, δ18O) and formation conditions of lower–middle Permian rocks in the Soyana River region (Arkhangel’sk district), Lithol. Miner. Resour., 2011, vol. 46, no. 3, pp. 265–281.CrossRefGoogle Scholar
- 34.Mii, H.-S., Grossman, E.L., and Yancey, T.E., Carboniferous isotope stratigraphies of North America: implications for Carboniferous paleoceanography and Missisipian glaciation, Bull. Geol. Soc. Am., 1999, vol. 111, no. 7, pp. 960–973.CrossRefGoogle Scholar
- 35.Mii, H.-S., Grossman, E.L., Yancey, T.E., et al., Isotopic records of brachiopod shells from the Russian Platform—evidence for the onset of mid-Carboniferous glaciation, Chem. Geol., 2001, vol. 175, pp. 133–147.CrossRefGoogle Scholar
- 36.Miller, D.J. and Eriksson, K.A., Linked sequence development and global climate change: the Upper Mississippian record in the Appalachian basin, Geology, 1999, vol. 27, no. 1, pp. 35–38.CrossRefGoogle Scholar
- 37.Misi, A., Kaufman, A.J., Veizer, J., et al., Chemostratigraphic correlation of Neoproterozoic successions in South America, Chem. Geol., 2007, vol. 237, pp. 143–167.CrossRefGoogle Scholar
- 38.Mizens, G.A, Kuleshov, V.N., Stepanova, T.I., and Kucheva, N.A., Reflection of the Famennian and Tournaisian global geological events in the isolated carbonate platform section on the east of the Urals, Russ. Geol. Geophys., 2015, vol. 56, no. 11, pp. 1945–1960.CrossRefGoogle Scholar
- 39.Mizens, G.A., Kuleshov, V.N., Sapurin, S.A., et al., Specific features of carbon and oxygen stable isotopes (δ13C and δ18O) geochemistry in the isolated carbonate platform section on the east of the Urals (the Famennian and Tournaisian Stages), Litosfera, 2016, no. 3, pp. 126–138.Google Scholar
- 40.Nemirovskaja, T.I. and Alekseev, A.S., Bashkirian conodonts of the Askyn section (Mountainous Bashkiria), Byull. MOIP. Otd. Geol., 1993, vol. 68, no. 1, pp. 65–86.Google Scholar
- 41.Pazukhin, V.N., Middle Carboniferous conodont assemblages in the Bashkir Cis-Urals, Mater. Vseross. Nauchn. Konf. “Verkhnii paleozoi Rossii: stratigrafiya i paleogeografiya”, 25–27 sentyabrya 2007 g., Kazan’ (Proc. All-Russ. Res. Conf. “Upper Paleozoic of Russia: Stratigraphy and Paleogeography,” September 25–27, 2007, Kazan), Kazan: Kazan. Gos. Univ., 2007, pp. 243–246.Google Scholar
- 42.Peryt, T.M. and Magaritz, M., Genesis of evaporate-associated platform dolomites: case study of the Main Dolomite (Zechstein, Upper Permian), Leba elevation, northern Poland, Sedimentology, 1990, vol. 37, no. 4, pp. 745–761.CrossRefGoogle Scholar
- 43.Pokrovsky, B.G. and Bujakaite, M.I., Geochemistry of C, O, and Sr isotopes in the Neoproterozoic carbonates from the southwestern Patom paleobasin, southern Middle Siberia, Lithol. Miner. Resour., 2015, vol. 50, no. 2, pp. 144–169.CrossRefGoogle Scholar
- 44.Pokrovsky, B.G. and Bujakaite, M.I., Isotopic compositions of C, O, Sr, and S and problem of ages of the Katera and Uakit Groups, western Transbaikal region, Lithol. Miner. Resour., 2016, vol. 51, no. 4, pp. 262–282.CrossRefGoogle Scholar
- 45.Popp, B.N., Anderson, T.F., and Sandberg, P.A., Brachiopods as indicators of original isotopic compositions in some Paleozoic limestones, Bull. Geol. Soc. Am., 1986, vol. 97, no. 10, pp. 1262–1269.CrossRefGoogle Scholar
- 46.Poulsen, C.J., Tabor, C., and White, J.D., Long-term climate forcing by atmospheric oxygen concentrations, Science, 2015, vol. 348, no. 6240, pp. 1238–1241.CrossRefGoogle Scholar
- 47.Proust, J.N., Chuvashov, B.I., Vennin, E., and Boisseau, T., Carbonate platform drowning in a foreland setting: the mid-Carboniferous platform in western Urals (Russia), J. Sedimentary Res., 1998, vol. 68, no. 6, pp. 1175–1188.CrossRefGoogle Scholar
- 48.Puchkov, V.N., Structural relationships between the Precambrian and Paleozoic at the periphery of the Bashkirian anticlinorium, Dokl. Ross. Akad. Nauk, 1997, vol. 352, no. 5, pp. 665–671.Google Scholar
- 49.Puchkov, V.N., Paleogeodinamika yuzhnogo i srednego Urala (Paleogeodynamics of the Southern and Middle Urals), Ufa: Dauriya, 2000 [in Russian].Google Scholar
- 50.Putevoditel’ ekskursii po razrezam karbona Yuzhnogo Urala (Bashkiriya) (Guidebook of the Geological Excursion for the Carboniferous Sections of the Southern Urals (Bashkiriya)), Moscow: Nauka, 1975 [in Russian].Google Scholar
- 51.Putevoditel’ geologicheskoi ekskursii po razrezam paleozoya i verkhnego dokembriya zapadnogo sklona Yuzhnogo Urala i Priural’ya (Guidebook of the Geological Excursion for the Paleozoic and Upper Precambrian Sections on the Western Slope of the Southern Urals), Ufa: Ufim. Nauchn. Tsentr RAN, 1995 [in Russian]. Google Scholar
- 52.Putevoditel’ geologicheskikh ekskursii po karbonu Urala. Ch. 1. Yuzhnoural’skaya ekskursiya (Guidebook of the Geological Excursion for the Carboniferous of the Urals. Part 1. Southern Urals Excursion), Ekaterinburg: Inst. Geol. Geokhim. Ural. Otd. RAN, 2002 [in Russian].Google Scholar
- 53.Rowley, D.B., Raymond, A., Parrish, J.T., et al., Carboniferous paleogeographic, phytogeographic, and paleoclimatic reconstructions, Int. J. Coal Geol., 1985, vol. 5, pp. 7–42.CrossRefGoogle Scholar
- 54.Saltzman, M.R., Carbon and oxygen isotope stratigraphy of the Lower Mississippian (Kinderhookian–early Osagaean), western United States: implications for seawater chemistry and glaciation, Bull. Geol. Soc. Am., 2002, vol. 114, pp. 96–108.CrossRefGoogle Scholar
- 55.Saltzman, M.R., The Late Paleozoic ice age: oceanic gateway or pCO2? Geology, 2003, vol. 31, pp. 151–154.CrossRefGoogle Scholar
- 56.Saltzman, M.R., Phosphorus, nitrogen, and the redox evolution of the Paleozoic oceans, Geology, 2005, vol. 33, pp. 573–576.CrossRefGoogle Scholar
- 57.Scholle, P.A., Albrechtsen, T., and Tirsgaard, H., Formation and diagenesis of bedding cycles in uppermost Cretaceous chalks of the Dan Field, Danish North Sea, Sedimentology, 1998, vol. 45, no. 2, pp. 223–243.CrossRefGoogle Scholar
- 58.Sedaeva, K.M., Ryabinkina, N.N., Kuleshov, V.N., and Valyaeva, O.V., Reflection of the Khangenberg global geological even at the Devonian–Carboniferous boundary in sections on the western slope of the Subpolar (Kozhim River) and South (Sikaza River) Urals, Litosfera, 2010, no. 6, pp. 25–37.Google Scholar
- 59.Semikhatov, M.A., Kuznetsov, A.B., Podkovyrov, V.N., et al., The Yudomian complex of stratotype area: C-isotope hemostratigraphic correlations and Yudomian–Vendian relation, Stratigr. Geol. Correl., 2004, vol. 12, no. 5, pp. 3–28.Google Scholar
- 60.Semikhatova, S.V., Brachiopods in the Bashkirian beds of the USSR, in Tr. PIN. T. XII. Vyp. 4 (Trans. Paleontol. Inst. Vol. XII. Iss. 4), Moskva-Leningrad: Izd. Akad. Nauk SSSR, 1941.Google Scholar
- 61.Semikhatova, S.V., Einor, O.L., Kireeva, G.D., et al., Bashkirian Stage in the planetary scale of the Carboniferous period, Tr. VIII Mezhd. Kongr. po stratigrafii i geologii karbona (Proc. VIII Int. Congr. on Carboniferous Stratigraphy and Geology), Moscow: Nauka, 1978, vol. 1, pp. 102–111.Google Scholar
- 62.Sinitsyna, Z.A., The Middle Carbonaceous reference section along the Askyn River, in Stratigrafiya i paleontologiya (Stratigraphy and Paleontology), Ufa: Bashkir. Fil. Akad. Nauk SSSR, 1974, vol. 24, pp. 64–69.Google Scholar
- 63.Sinitsyna, Z.A. and Sinitsyn, I.I., Geologicheskaya karta SSSR masshtaba 1 : 200000. List N-40-XV. Ob"yasnitel’naya zapiska (The 1 : 200000 Geological Map of the USSR. Sheet N-40-XV. Explanatory Note), Moscow: Gosgeoltekhizdat, 1962 [in Russian].Google Scholar
- 64.Sinitsyna, Z.A. and Sinitsyn, I.I., Biostratigrafiya bashkirskogo yarusa v stratotipe (Biostratigraphy of the Bashkirian Stage at its Stratotype), Ufa: Bashkir. Fil. Akad. Nauk SSSR, 1987 [in Russian].Google Scholar
- 65.Smith, L.B., Jr. and Read, J.F., Rapid onset of late Paleozoic glaciation on Gondwana: evidence from Upper Mississippian strata of the Midcontinent, United States, Geology, 2000, vol. 29, pp. 279–282.CrossRefGoogle Scholar
- 66.Stratigraficheskie skhemy Urala (dokembrii, paleozoi) (Stratigraphic Schemes of the Urals (Precambrian, Paleozoic)), Ekaterinburg: Mezhved. Stratigr. Kom. Rossii, 1993 [in Russian].Google Scholar
- 67.Sungatullin, Z.Kh., Kuleshov, V.N., and Kadyrov, R.I., Isotope composition (δ13C and δ18O) of dolomites from the Permian evaporite strata of the eastern Russian Plate (using the Syukeevskii gypsum deposits as an example), Lithol. Miner. Resour., 2014, vol. 49, no. 5, pp. 406–415.CrossRefGoogle Scholar
- 68.Teodorovich, G.I., Bashkirian Stage within the Ural–Volga region, Byull. MOIP. Otd. Geol., 1952, vol. XXVII, no. 1, pp. 18–27.Google Scholar
- 69.Teodorovich, G.I., Subdivision of reference sections of the Bashkirian Stage in the Mountainous Bashkiria into faunistic horizons, Byull. MOIP. Otd. Geol., 1957, vol. XXXII, no. 3, pp. 65–80.Google Scholar
- 70.Teodorovich, G.I., The stratotype section of the Bashkirian Stage and its stratigraphic subdivisions, in Biostratigrafiya neftenosnykh oblastei SSSR (Biostratigraphy of Petroleum Basins of the USSR), Moscow: Nauka, 1964, pp. 13–58.Google Scholar
- 71.The Geologic Time Scale 2012, Gradstein, F.M., Ogg, J.G., Schmitz, M.D., and Ogg, G.M., Eds., Amsterdam–Tokio: Elsevier, 2012.Google Scholar
- 72.Veevers, J.J. and Powell, C.M., Late Paleozoic glacial episodes in Gondwanaland reflected in transgressive–regressive depositional sequences in Euramerica, Bull. Geol. Soc. Am., 1987, vol. 98, pp. 475–487.CrossRefGoogle Scholar
- 73.Veimarn, A.B., Naidin, D.P., Kopaevich, L.F., et al., Metody analiza global’nykh katastroficheskikh sobytii pri detal’nykh stratigraficheskikh issledovaniyakh: metodicheskie rekomendatsii (Methods of Analysis of Global Catastrophic Events at the Detailed Stratigraphic Studies: Methodical Recommendations), Moscow: Mosk. Gos. Univ., 1998 [in Russian].Google Scholar
- 74.Veizer, J., Ala, D., Azmy, K., et al., 87Sr/86Sr, δ13C and δ18O evolution of Phanerozoic seawater, in Earth System Evolution, Geochemical Perspective, Veizer, J., Ed., Chem. Geol., 1999, vol. 161, nos. 1–3, pp. 59–88.Google Scholar
- 75.Wright, V.P. and Vanstone, S.D., Onset of the late Paleozoic glacio-eustasy and the evolving climates of low latitude areas: a synthesis of current understanding, J. Geol. Soc. London, 2001, vol. 158, pp. 579–582.CrossRefGoogle Scholar
- 76.Wynn, T.C. and Read, J.F., Carbon-oxygen isotope signal of Mississippian slope carbonates, Appalachians, USA: a complex response to climate-driven fourth-order glacio-eustasy, Palaeogeogr., Palaeoclimatol., Palaeoecol., 2007, vol. 256, pp. 254–272.CrossRefGoogle Scholar
- 77.Zhou, C. and Xiao, S., Ediacaran δ13C chemostratigraphy of South China, Chem. Geol., 2007, vol. 89, pp. 89–108.CrossRefGoogle Scholar
- 78.Zhuravlev, A.Yu. and Wood, R., Controls on carbonate skeletal mineralogy: global CO2 evolution and mass extinctions, Geology, 2009, vol. 37, no. 12, pp. 113–1126.CrossRefGoogle Scholar