ANOXIA AND ORGANIC MATTER CHARACTERIZATION OF NEW YORK’S BLACK SHALES

Several black shale formations, ranging from Ordovician to Devonian in age, outcrop in New York State. These shales have been shown to be significant sources of unconventional gas, suggesting high levels of organic material preserved due to anoxic conditions within the basin during deposition. Variations in major and trace elements, and organic matter lipid characterization, may lead to a better understanding of depositional environments within the paleobasins. Eight samples from the Marcellus Shale were obtained from outcrops and quarries that span an east to west band in New York, and three from the Utica Shale. Whole rock analysis for major and trace elements and organic matter lipid profiles were determined for each sample. All samples showed negative Ce anomalies, indicating that anoxic conditions were present during deposition. These values, however, show no correlation with spatial distribution across the state. A correlation between organic matter and Ni, another indicator of anoxic conditions, is present, with an r² of 0.97 which is supported by Lewan, M. D., & Maynard, J. B. (1982). This indicates algae as the probable source of the organic matter. Total organic matter content values range from 2.43 to 17.48 (wt%) as determined by loss on ignition, however, no clear trend could be observed related to distribution across the state. Total extractable lipids, however, does show a spatial trend, with values increasing as you move from west to east across the State within the Marcellus. Furthermore, Marcellus samples show significantly higher total lipids when compared to Utica samples. Detailed characterization of lipids is underway, and may shed light on the source of organic matter and preservation.