The Dynamics of Rapid, Asynchronous Biotic Turnover in the Middle Devonian Appalachian Basin of New York

Title:	The Dynamics of Rapid, Asynchronous Biotic Turnover in the Middle Devonian Appalachian Basin of New York
Author:	Sessa, Jocelyn
Description:	High resolution stratigraphic and paleoecological analyses of regional biotic turnovers can reveal much about their evolutionary and ecological processes. Biotic turnover in the Devonian of the Appalachian Basin was investigated to determine whether taxonomic replacement across a key boundary was: 1) abrupt or gradual; 2) synchronous across the basin. Analyses of abundance data that reveal a depth-controlled gradient persisted, with moderate variation, until just prior to the boundary. Two biotic assemblages occur above and below the boundary, while another occurs only above it. Turnover was asynchronous; certain assemblages appeared earlier than others. Above the boundary, a unique assemblage appeared abruptly, another assemblage appeared gradually, and a third remained unchanged. Taxonomic composition was controlled by sedimentologic/environmental variables; specific faunas occur in particular lithofacies. Many taxa were not facies restricted, and occurred in many environments, but their abundance varied significantly. Taxon abundance and paleoenvironmental context is therefore important for understanding biotic transitions.
Permanent Link:	http://rave.ohiolink.edu/etdc/view?acc_num=ucin1054576413 http://hdl.handle.net/2374.OX/105975
Date:	2003

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