Stratigraphic framework of early Pliocene fossil localities along the north bank of the Cimarron River, Meade County, Kansas
James G. Honey 1 , Pablo Peláez-Campomanes 2 and Robert A. Martin 3
1 Geology Section, University of Colorado, Boulder 80309-0315, USA. [email protected]
2 Department of Paleobiology, National Museum of Natural History, C.S.I.C., Jose Guttierez Abascal 2, Madrid 28006, Spain. [email protected]
3 Department of Biological Sciences, Murray State University, Murray, KY 42071, USA. [email protected]
Abstract. The stratigraphy of early Pliocene (early Blancan) fossiliferous sediments exposed in canyons along the north bank of the Cimarron River in Meade County, Kansas is described as part of a larger, ongoing project to create a refined biostratigraphic model for late Neogene and Pleistocene mammalian fossil localities from the Meade Basin. Because the utility of previously named formation and member names is questionable, we introduce a set of informal names for stratigraphic units in our study area. Sediments in the region are up to 34 m thick, and include a basal sand and gravel (?Bishop gravel?) at least 9 m thick, overlain by up to 17 m of lightto pinkish-gray, fine-grained sand and silt, with interbedded calcium carbonate layers. These fine-grained sediments are overlain in turn by a second, 8.5 m-thick sand and gravel (?Wolf gravel?) that is itself overlain by about 5 m of calcareous silts culminating in a thick caliche. The stratigraphic positions of fifteen fossil localities, some with rich vertebrate assemblages, were determined in this study. The sites are found in a variety of sediments representing fluvial, pond, spring, and sinkhole depositional environments. Rodent fossils are especially common, and certain taxa, such as the geomyids, sigmodontines, and arvicolids, support the stratigraphic hypothesis based on field mapping. This combined stratigraphic and faunal information provides an essential part of the early Pliocene component of the Meade Basin Neogene and Pleistocene faunal database, to be used to examine the history of biological diversity in southwestern Kansas.
Ameghiniana, Mar./June 2005, vol.42, no.2, p.461-472.