Carbon Isotope Chemostratigraphic Records from Well Cuttings for Global Correlation of Non-marine Sections

Jessica H. Whiteside
Lamont-Doherty Earth Observatory of Columbia University, Department of Earth and Environmental Sciences
Palisades, NY
jhw@ldeo.columbia.edu

Long-range correlation of continental sections sampled by drilling are fraught with well-known difficulties largely because of the low temporal resolution of continental palynology, endemism of pollen and spore taxa, and sparse biostratigraphic registry to marine sections. However, vascular plant material (e.g. pollen spores, cuticles and woody tissues) contains a record of globally correlative processes in stable carbon isotopes, which preserve, with characteristic fractionations, the isotopic composition of atmospheric CO2, which in turn reflects the marine surface carbon reservoirs. The δ¹³C of these shallow oceanic reservoirs fluctuate in time, producing a potentially rich historical record of atmospheric variations in vascular plant material. Contributions to δ¹³C fluctuations include cyclical, Milankovitch related processes in the ocean and random events such as times of enhanced carbon burial, deep ocean light carbon reservoir release or extraterrestrial impact, and changes in the source of fossil carbon. This project will develop a δ¹³C chemostratigraphy for about 20 my of the continental Triassic portion of the Newark rift basin based on standard industry 10 ft well cuttings (composited to 30 ft to keep the sample number reasonable). Not only will this chemostratigraphy be tied to a well developed astronomically tuned geomagnetic polarity time scale based on continuous cores from the Newark basin (funded by US NSF), it also will provide the basis for test of concept for a globally correlative δ¹³C chemostratigraphy that should allow unambiguous correlation to other vascular plant material records in frontier areas.