Former Presence of Thick Post-Devonian Strata in Northern Appalachian Basin: Evidence from Fluid-Inclusion Studies: ABSTRACT

Abstract

Along an 80-km long belt south of Syracuse, New York, the maximum fluid-inclusion homogenization temperatures (T{sub max}) of late-stage cements of the lower Middle Devonian Onondaga Limestone show a local high of 150{degree}-160{degree}C in central New York. T{sub max} decreases both west and east of this area reaching about 100{degree}C in outcrops near Buffalo and Albany, respectively. Southward from Albany, along the western margin of the Hudson Valley, T{sub max} again rises sharply to 170{degree}-180{degree}C in the Kingston area. The thermal alteration index (TAI) and vitrinite reflectance of the overlying Marcellus-Bakoven (Middle Devonian) black shales in central and eastern New York show a comparable trend. The east-west profile of T{sub max} of the Onondaga rocks as well as thermal maturity of the black shales show excellent correlation with similar profiles of authigenic magnetite in the Onondaga Limestone and of clay diagenesis and fission-track ages of the Middle Devonian Tioga Metabentonite Bed, as reported by others. The T{sub max} of the Onondaga Limestone is believed to have been attained during maximum burial, the extent of which can not be accounted for by the present thickness of post-Onondaga strata. As a result of an inferred late Paleozoic uplift, in western and easternmore » New York, 2-3 km of post-Devonian strata were removed, in central New York 4-5 km, and in southeastern New York 5-6 km were removed. The north-south variation in maximum burial along the Hudson Valley may be explained by additional impact of tectonic loading in the south.« less