Synchronous Sediment Accumulation, Decompaction and Subsidence in the Miocene Foreland Basin of Northern Pakistan
Abstract
Previous magnetostratigraphic studies in northern Pakistan provide a tightly constrained temporal framework within which to analyze the sediment accumulation history of the northwestern Himalayan foreland basin. Paleocurrent and provenance data indicate that a longitudinal drainage system flowing to the ESE persisted through much of the middle and late Miocene deposition. The subhorizontal cross-sectional surfaces defined by the paleodrainage configurations provide a reference frame for analyzing subsidence histories. Six magnetic sections in the Potwar Plateau have been decompacted as a function of burial depth and lithology to provide both accumulation and subsidence records. These records demonstrate consistently higher amounts of accumulation and subsidence in the northern portions of the basin, but also indicate that events of tectonic loading were experienced synchronously across the basin. Inflections in the curves of tectonically induced subsidence suggest that an important interval of thrust loading began ~11.5 Ma and terminated ~8 Ma.
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