294— Investigation of sub-precession cyclostratigraphy within the Hanover Formation, Late Devonian, western New York

The Late Devonian, from 383-359 Ma, was a period of continual ecological restructuring and biodiversity loss, often grouping it amongst the five mass extinction events within the Phanerozoic Eon. The Upper Devonian Hanover Formation, within the Java Group, consists of bioturbated green-gray silty shale interbedded with black shale that pre-date and preserve the extinction. Depositional cycles within the Hanover that coincide with eccentricity, obliquity, and precession intervals have been recognized. The eccentricity, obliquity, and precession intervals occur in periods of 100 to 416 Ka, 41 to 51 Ka, and 19 to 21 Ka respectively. To accurately identify sub-precession cycles, high resolution sampling at 1 cm intervals through 2 m of core are being analyzed for magnetic susceptibility (MS) using a Kappa-bridge. The detection of detrital iron through MS measures the induced magnetization of deposited sediments, which vary due to changes in the depositional environment caused by variations in eustatic sea level and climatic conditions. The frequency of the MS changes within the recognized precession cycles will reveal the duration of the sub-precession cyclicity.