On the periodicity and magnitude of Late Carboniferous glacio-eustatie sea-level changes

Abstract

Data from sedimentary cycles in basins from northern England, the Appalachians and Midcontinent US afford an insight into periodicities and controls of Late Carboniferous glacio-eustatic sea-level changes. Lithofacies with identifiable palaeobathymetry are used to assess the magnitude of sea-level change in the Pennine Basin of northern England; the method yields a minimum value of 42m. Walsh power spectral analysis is employed to resolve periodicities of about 120ka within the Pennine Basin of northern England, 212, 140 and 93 ka within the Midcontinent US succession and 109, 84, 67, 63 ka within the Appalachian Basin. Within the Pennine Basin periodicities and magnitudes are found to be independent of their position within the basin thus any tectonism can be assumed to have had a negligible effect on the transgressions. A simplified modelled climatic curve is derived from Milankovitch parameters and Pleistocene δ 18 O data. This is used in a basin fill model that simulates the thermally subsiding Pennine Basin. The resulting distribution of marine deposits is seen to depend upon both the steady regional subsidence and the magnitude and extent of glacio-eustatic transgressions.