4 Conodonts Solving Stratigraphic Problems

Sunday, 19 March 2017
8:00 AM - 12:00 PM
Lawrence Welk Room, Mezzanine Level

HIGH FRASNIAN CONODONTS FROM THE CANASERAGA SANDSTONE, JAVA GROUP, UPPER DEVONIAN, WESTERN NEW YORK

Paper number: 4-4
Program: Theme Sessions
Time: 8:45 AM – 9:05 AM

Authors

Abstract

A fossiliferous calcite cemented conglomeratic sandstone formed at the base of a large channel feature in the marine strata of the Canaseraga Sandstone, close to the Frasnian-Famennian boundary (Upper Devonian), contains a diverse Polygnathus (Conodont) fauna in addition to fauna typical of a deep shelf environment, including the brachiopods Cyrtospitrifer sp. aff. C. whitneyi, Spinatrypa sp. aff. S. compacta, Nervostrophia sp. Douvillina sp. Douvillinaria cf. D. perversa, and Pseudodouvillina cf. P. euglyphea, as well as bivalves, bryozoans, cephalopods, corals, crinoids, and fish. The genera Douvillinaria and Pseudodouvillina became extinct in central and western North America shelves during the Lower Kellwasser extinction (LKE) in the uppermost part of Frasnian Zone 12. Nervostrophia occurs in post-LKE Frasnian Zone 13a strata in the Iowa Basin, and Cyrtospirifer ranges into early Famennian rocks in eastern and western North America. Spinatrypa compacta Cooper and Dutro, is restricted to Frasnian Zone 13a deposits of the Contadero Formation in the San Andres Mountains in southern New Mexico, although similar species such as S. trulla first occur in Frasnian Zone 11 deposits but are extinct in Iowa at the close of the LKE. The conodonts include Polygnathus aequalis, Po. alatus, Po. brevis, Po. webbi, and at least one new Polygnathus taxon, as well as two palmatolepid fragments suggestive of Palmatolepis hassi. Both the conodont and brachiopod faunas are typical of an Upper Devonian offshore shelf environment. The conodont fauna is may be as young as Frasnian Zone 13 in the Late Frasnian. The channel is speculatively representative of a significant sea-level fall at the end of the Frasnian that coincides with the Frasnian-Famennian boundary.

Geological Society of America Abstracts with Programs. Vol. 49, No. 2

doi: 10.1130/abs/2017NE-290088

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