Sandstone provenance and sediment dispersal in a complex tectonic setting: Taranaki Basin, New Zealand

A transition period ensued from the Late Eocene to Early Miocene associated with a change in basin tectonics from passive margin to active margin. Compositional and detrital zircon U-Pb data indicate that rocks to the east of Taranaki Basin became emergent, with progressive erosion of Cretaceous-Eocene cover rocks and underlying basement terranes. Minor, southward-propagating uplift of the eastern basin margin was initiated in the latest Eocene, and by the Late Oligocene, provenance and sedimentation patterns had clearly changed with the earliest Miocene strata sourced from eastern metasedimentary basement rocks. The Eastern Province continued to be a major sediment source through the active margin phase, but mixed with the re-appearance of granite (?reworked) sources and Miocene volcaniclastic detritus. These changes in sediment provenance through time are displayed on a set of eight sediment dispersal maps, which can be used to help predict composition, and hence reservoir quality, in undrilled parts of the basin.