Burial and exhumation history of Pennsylvanian strata, central Appalachian basin: an integrated study

Abstract

AbstractAn inferred burial and exhumation history of Pennsylvanian strata in the central Appalachian foreland basin is constrained by integrating palaeothermometers, geochronometers and estimated palaeogeothermal gradients. Vitrinite reflectance data and fluid inclusion homogenization temperatures indicate that burial of Lower and Upper Pennsylvanian strata of the Appalachian Plateau in West Virginia exceeded ∼4.4 km during the late Permian and occurred at a rate of ∼100 m Myr−1. Exhumation rates of ∼10 m Myr−1 from the late Permian to the early Cretaceous are constrained using maximum burial conditions and published apatite fission track (AFT) ages. AFT and radiogenic helium ages indicate exhumation rates of ∼30–50 m Myr−1 from the early to late Cretaceous. Radiogenic helium dates and present day sampling depths indicate that exhumation rates from the late Cretaceous to present were ∼25 m Myr−1. Exhumation rates for Upper and Lower Pennsylvanian strata within the Appalachian Plateau are remarkably similar. Early slow exhumation was possibly driven primarily by isostatic rebound associated with Triassic rifting. The later, more rapid exhumation can be attributed to thermal expansion followed by lithospheric flexure related to sediment loading along the passive margin.