2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 229-14
Presentation Time: 9:00 AM-6:30 PM


STUBBS, Dreadnaught G.1, NADON, Gregory C.1 and THOMAS, William A.2, (1)Geological Sciences, Ohio University, 316 Clippinger Lab, Athens, OH 45701, (2)Emeritus University of Kentucky, Geological Survey of Alabama, P.O. Box 869999, Tuscaloosa, AL 35486-6999, ds186410@ohio.edu

The Sharon Conglomerate is a basal Pennsylvanian quartz arenite to quartzose conglomerate as much as 84 m thick. An exposure in northeastern Ohio is similar in composition and stratigraphic position to a separate exposure 250 km to the southeast. Both exposures have been interpreted as braided fluvial deposits by several earlier studies, which have interpreted the two lithosomes to have the same or different provenance on the basis of optical petrography and/or heavy mineral content. Published paleocurrent data indicate that the northern sandstone had a northern source, whereas the southern lithosome was derived from the southeast. Two samples of similar grain size were collected from each exposure for thin-section analysis and additional samples were collected from the same sites for detrital zircon analysis and analyzed at the Arizona LaserChron Center. Chi-square tests of both point-count and grain-count data produced mixed results. Comparisons within sample sites rejected the null hypothesis, and those between exposures failed to reject, suggesting that with this small sample size the intra-site variability is as great as the inter-site differences. The zircon-age distributions in both Sharon samples have a major peak in the Mesoproterozoic (Grenville) and a smaller peak in the Ordovician (Taconic). The comparison of the zircon age distributions in the two Sharon samples using the Kolmogorov-Smirnov (K-S) test, failed to reject the null hypothesis, indicating the samples share the same provenance. The Sharon zircon data were also compared to those of Lower Pennsylvanian strata in Pennsylvania and West Virginia using the K-S test. The comparisons to the West Virginia data rejected the null hypothesis, and the comparisons to the Pennsylvania data failed to reject the null hypothesis. The zircon data show that both Ohio quartz arenites share the same provenance and that the source area was likely in eastern Pennsylvania.