Wong, Th. E. (Ed.): Proceedings of the XVth International Congress on Carboniferous and Permian Stratigraphy. Utrecht, the Netherlands, 10–16 August 2003. Royal Netherlands Academy of Arts and Sciences Carboniferous echinoderm zonation in the Appalachian Basin, eastern USA F.R. Ettensohn 1,W.I.Ausich2,T.W.Kammer3, W.K. Johnson 1 & D.R. Chesnut, Jr. 4 1 Department of Earth & Environmental Sciences, University of Kentucky, Lexington, KY 40506, USA; e-mail:
[email protected] 2 Department of Geological Sciences, Ohio State University, Columbus, OH 43210, USA 3 Department of Geology and Geography, West Virginia University, Morgantown, WV 26506, USA 4 Kentucky Geological Survey, University of Kentucky, Lexington, KY 40506, USA Abstract The Carboniferous was a period of major echinoderm evolution, especially during Mississippian (Early Car- boniferous) time when crinoids, blastoids, and echinoids increased dramatically in abundance and diversity. The high degree of structural organization and distinctive morphologies of echinoderms make them ideal zonal indicators, and for parts of the Appalachian Basin Mississippian section, they provide greater biostratigraphic resolution than do conodonts or foraminifera. The occurrence of various echinoderm groups in time and space, however, is clearly related to the tectonic and sedimentologic differentiation of the Appalachian Basin through time. By Early Mississippian time on the Laurussian continent, most echinoderms had already made the shift to clastic-rich environments, which predominated in the basin until Middle Mississippian time. Although present, well-preserved Kinderhookian, Osagean, and Meramecian echinoderms are rare in the Appalachian Basin, and most are endemic forms with little diagnostic value. Echinoderms did, however, become especially abundant in the succeeding, late Middle and early Late Mississippian (Late Meramecian–Middle Chesterian), carbonate-rich seas, and it is for this time interval that biostratigraphic resolution, based especially on crinoids and blastoids, is best.