Physical and chemical evolution of a Pleistocene marginal marine gold paleoplacer deposit, southern New Zealand

Abstract

Abstract Pleistocene placer gold accumulation in coastal sediments during fluctuating Pleistocene sea levels and active tectonic uplift in southern New Zealand provides a well-constrained model for processes that have affected paleoplacers formed in similar settings in older rocks, going back to the Archean. Initial gold concentration occurred\xa0>\xa0200 ky ago on exposed sandy beaches, where sand-blasting processes deformed fluvially-transported (~200\xa0km) flakes into toroids, dumbells and spheroids. This gold was recycled into younger gravel-bearing sediments\xa0 50\xa0m) with negligible morphological changes during