2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 8
Presentation Time: 3:35 PM

U-Pb Calibrated Cyclo- and Bio-Stratigraphy of the Permo-Carboniferous Sucession, Donets Basin, Ukraine

EROS, James M.1, MONTANEZ, Isabel1, DAVYDOV, Vladimir I.2, CROWLEY, J.L.3, NEMYROVSKA, Tamara I.4, POLETAEV, Vladislav I.4 and GULBRANSON, Erik L.1, (1)Department of Geology, University of California, Davis, CA 95616, (2)Department of Geosciences, Boise State Univ, 1910 University Drive, Boise, ID 83725, (3)Department of Geosciences, Boise State University, 1910 University Drive, Boise, ID 83725, (4)Institute of Geological Sciences, National Academy of Sciences of Ukraine, O. Gonchar Street, 55-b, Kiev, 052054, Ukraine, eros@geology.ucdavis.edu

The Late Paleozoic Donets Basin of eastern Ukraine records near-continuous, paralic (marine to terrestrial deltaic facies), cyclothemic facies of early Mississippian through early Permian age.  Tectonic reconstructions place the Donets Basin in paleotropical eastern Pangea along the northwestern Tethyan margin between 10° S - 10° N latitude for the duration of the late Paleozoic ice age (LPIA).  Field studies in the Donets Basin coupled with analysis of high-resolution seismic-scale log data identify twelve major cycle types that define clear stratigraphic and spatial trends. New age constraints developed from high-resolution biostratigraphy (conodonts, foraminifera) and ID-TIMS U-Pb dating of zircons from  tonsteins (< 0.1% external precision) in the Donets Basin calibrate its cyclothemic record to an unprecedented degree.  Relative sea-level history and climate conditions inferred from these cyclostratigraphic trends vary in concert with recently developed high-latitude records of LPIA glaciation. Periods of regional aridity are inferred (intercalated limestones and evaporites, sabhka evaporite deposits) for periods of high-latitude glacial minima while increased coal deposits and indicators of increased regional seasonality and fluvial transport (humidity) define periods of glacial maxima. Four intervals corresponding to potentially ice-free conditions or glacial minima are indicated, with at least four discreet periods corresponding to glaciation also recorded. These findings are in broad agreement with recently-developed high-latitude sedimentary records of the LPIA glaciation. Comparison of these records in the Donets Basin with existing coeval Permo-Carboniferous records from paleotropical basins address the nature of glacioeustasy in the LPIA and its relationship to climate and reconstructed Southern Gondwanan glacial history.