PALYNOFACIES ANALYSIS AND BIOSTRATIGRAPHIC CORRELATION ACROSS THE DEVONIAN CATSKILL FRONT

We have begun a project to examine the palynology of Middle to Upper Devonian rocks in New York State with three generalized goals in mind: 1) Correlation of non-marine rocks of the Catskills area with the marine succession that is so well documented in western New York; 2) Characterization of past sedimentary environments using developing techniques in palynofacies analysis; and 3) Documentation of the effects of terrestrialization (especially the rise of true forests) in non-marine, paralic and near-shore sedimentary facies by examining the distribution and types of buried organic carbon (maceral analysis).

Stratigraphic correlations between the Catskill magnafacies and time-equivalent marine rocks across New York State have proven notoriously problematic. Great variability in fluvial depositional processes, the lack of distinctive marker beds, generally poor exposure, and the absence of traditional invertebrate guide fossils in the nonmarine units have all contributed to this situation. Traverse and Schuyler (1994) used palynomorphs successfully to correlate nonmarine, marginal marine and marine facies of the Frasnian Oneonta, Walton and Slide Mountain Formations across the Catskill front. We are examining the older Givetian-age Ashokan, Plattekill and Manorkill Formations, which contain well-preserved spores and rare acritarchs such as Cymatiosphaera and Diexallophasis. In addition to biostratigraphic correlation, we hope to use inter-sample variability as a metric for characterizing depositional settings. This expands on clustering techniques applied successfully elsewhere in eastern North America (Beck and Strother, 2001; in press). Wood fragments and individual tubular elements (nematoclasts) are present in these samples. They may be useful in tracking the influx of detrital carbon into paralic and near-shore marine settings during the initial rise of Earth’s earliest forested landscapes.