Value of Coenocorrelation Curves in Documenting Sea Level Changes in Appalachian Basin During Late Silurian and Early Devonian

Sam Wong

A detailed paleoecological analysis of the Keyser Limestone was conducted at five localities in Virginia and West Virginia, using two multivariate statistical techniques: cluster analysis and detrended correspondence analysis. Through this analysis, the Keyser fauna was divided into communities along a nearshore to offshore environmental gradient, and each community was assigned to a benthic assemblage. Having established the proximity of the various faunal elements to the shoreline, the faunal zones at other localities, as described in the literature, were assigned to the appropriate benthic assemblage. Coenocorrelation curves were then constructed, based on benthic assemblage membership. By correlating the curves between each locality, the history of sea level changes i the Appalachian basin during the Late Silurian to Early Devonian were determined.

Through this technique, more localities can be incorporated into detailed basin analysis studies. In this study, using coenocorrelation curves, it was found that the Keyser Limestone records several transgressive pulses. An initial transgressive pulse, affecting Virginia and West Virginia, resulted in the deposition of facies containing benthic assemblages 4 and 5. A second transgressive pulse resulted in the extension of these facies into Pennsylvania and New York. This transgressive pulse was followed by regressive conditions and the expansion of facies containing benthic assemblage 3. Subsequent transgression led to a return of facies containing benthic assemblages 4 and 5. Keyser deposition ended with a major regressive event, as recorded in the deposition of facies containing ben hic assemblages 1-3.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.