EES Professor Contributes to Catskill Mountains Study
Paul Fitzgerald, professor of earth and environmental sciences, is co-author on a paper titled, Episodic exhumation of the Appalachian orogen in the Catskill Mountains, which recently appeared in the journal Geology. He and lead author Chilisa M. Shorten, who received a doctoral degree in earth sciences from Syracuse University and is now a Mendenhall Postdoctoral Fellow and Research Geologist with the U.S. Geological Survey, used low-temperature thermochronology to constrain the episodic cooling and exhumation history of the Catskill Mountains.
Abstract: Increasing evidence indicates the eastern North American passive margin has not remained tectonically quiescent since Jurassic continental breakup. The identification, timing, resolution, and significance of post-orogenic exhumation, notably an enigmatic Miocene event, are debated. We add insight by constraining the episodic cooling and exhumation history of the Catskill Mountains (New York, USA) utilizing apatite fission-track thermochronology and apatite (U-Th)/He data from a ~1 km vertical profile. Multi-kinetic inverse thermal modeling constrains three phases of cooling: Early Jurassic to Early Cretaceous (1–3 °C/m.y.), Early Cretaceous to early Miocene (~0.5 °C/m.y.), and since Miocene times (1–2 °C/m.y.). Previous thermochronologic studies were unable to verify late-stage cooling and/or exhumation (typically post-Miocene and younger) because late-stage cooling was commonly a spurious artifact of earlier mono-kinetic annealing algorithms. Episodic cooling phases are correlative with rifting, passive-margin development, and drainage reorganization causing landscape rejuvenation. Geomorphologic documentation of increased offshore mid-Atlantic sedimentation rates and onshore erosion support the documented accelerated Miocene cooling and exhumation.