The geology of the Sau River and environs, New Guinea

Updated: 2026-05-04

An area of approximately 800 square miles in the Western Highlands of New Guinea was mapped during a reconnaissance geological survey in 1959. Non-metamorphic Jurassic fine-grained marine sediments and Lower Cretaceous volcanics are faulted against an Eocene to Pliocene sequence of marine sediments and volcanics; these rocks are openly folded along northwest trending axes and dislocated by two major north-west trending faults. Pleistocene basic volcanics and alluvial deposits are the youngest rocks. A large basic pluton which intrudes Miocene and older rocks is the source of gold, platinum, and minor copper mineralisation.