Low Temperature Thermochronologic Constraints on the Thermal History, Hydrocarbon Potential and Tectonic Evolution Across the Northern Appalachian Basin
Department of Earth Sciences/Thermochronology, Syracuse University, Syracuse, NY, USA
We aim to conduct a targeted, systematic low-temperature thermochronologic study of the Northern Appalachian Basin along an east-west transect located along the New York-Pennsylvania border. Our target samples are Devonian sandstones lying stratigraphically above and below the Marcellus Shale. These Devonian sandstone units contain apatite mineral grains, allowing us to apply apatite fission track thermochronology to constrain the tectonic and thermal history of the basin.
Apatite fission track thermochronology has implications for constraining suitable conditions for shale natural gas generation because the partial annealing zone, ~60-120°C depending on the apatite composition, significantly overlaps the hydrocarbon generation window. We plan to combine apatite fission track thermochronology data with known absolute temperature indicators; conodont alteration index and vitrinite reflectance, as well as the depositional ages of the sandstone units. All of this information provides input for inverse thermal modeling to constrain the time-temperature envelopes of good fit thermal histories. With this thermal data, the exhumation history of the basin, conditions suitable for hydrocarbon generation, and the location where those conditions existed can be determined.
Our hypothesis is that sediments will be over mature for hydrocarbon generation on the eastern flank of the basin, becoming under-mature towards the shallowing western side since this foreland basin is asymmetric. Due to the well-known geometry of the basin, we can extrapolate information about the thermal history and tectonics of one part of the basin to make conclusions about the entire basin. We anticipate finding local complications and variations but assume this will be the general trend.
AAPG Search and Discovery Article #90199 © 2014 AAPG Foundation 2014 Grants-in-Aid Projects