Conodont biostratigraphy and paleoecology of the Lower Devonian Helderberg Group of Virginia

dc.contributor.authorCook, Elizabeth G.en
dc.contributor.departmentGeological Sciencesen
dc.description.abstractThe occurrences of species of Delotaxis and Icriodus and the Ozarkodina remscheidensis eosteinhornensis--Ozarkodina remscheidensis remscheidensis lineage indicate that (1) most of the Keyser Formation of western Virginia is assignable to the uppermost Silurian eosteinhornensis zone; (2) the top of the upper limestone member of the Keyser is assignable to the basal Devonian woschmidti zone; (3) the remainder of the Helderberg Group is no younger than the delta zone; and (4) the basal Needmore Shale at the Price's Bluff section is assignable to the serotinus, patulus, or costatus costatus zones, of uppermost lower Devonian and lowermost Middle Devonian age, leaving a gap of at least six conodont zones represented by the Ridgeley Sandstone and its bounding unconformities. Conodonts tend to avoid tidal flat and lagoonal environments. They are not uniformly distributed through the rest of the section, but the occurrence of all but two species is not related to water depth, energy, or substrate; Ozarkodina excavata and Pseudooneotodus beckmanni prefer moderate energy environments. Icriodus helderbergensis and most of the simple cone species are associated with each other. There were 13,360 specimens collected, divided among 10 biological species and 15 form species; of the biological species, 3 are new and 2 are newly reconstructed apparatuses.en
dc.description.degreeMaster of Scienceen
dc.format.extentvii, 152, [2] leavesen
dc.publisherVirginia Polytechnic Institute and State Universityen
dc.relation.isformatofOCLC# 7906502en
dc.rightsIn Copyrighten
dc.subject.lccLD5655.V855 1981.C564en
dc.subject.lcshPaleoecology -- Virginiaen
dc.titleConodont biostratigraphy and paleoecology of the Lower Devonian Helderberg Group of Virginiaen
dc.type.dcmitypeTexten Sciencesen Polytechnic Institute and State Universityen of Scienceen
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