Aspects of the quaternary geology of the Tari‐Koroba area, Papua

Abstract

The Tari‐Koroba district is at an altitude of about 1,500 m in the Southern Highlands of Papua in an imbricate province in which uplift and faulting occurred in Pliocene times. In the southeast of the area Miocene limestones are overlain by volcanic rocks erupted about 0.85 m.y. ago, as determined from K‐Ar measurements. These middle Pleistocene flows crossed the course of the Tagari River, damming its waters to form Lake Haibuga. Sediments accumulated in this and neighbouring basins. At one site near Pureni, diprotodontid remains were found; wood associated with the deposit gave a ¹⁴C age of 32,700 yrs B.P. Pollen from this fossiliferous horizon and from another section nearby (¹⁴C age of 38,600 yrs B.P.) indicate that the climate was cooler than at present and perhaps equivalent to that experienced at about 600 m higher elevation today. Pollen from stratigraphically lower samples indicate still colder conditions and may reflect a glacial phase in the highlands earlier than the last glaciation.