Geology and offshore petroleum prospects of the eastern New Ireland Basin, northeastern Papua New Guinea

The eastern part of the New Ireland Basin of Papua New Guinea is about 600 km long by 150 km wide and mostly offshore, northeast of New Hanover and New Ireland. Basin geology and petroleum prospects have been interpreted from onshore geology integrated with offshore seismic reflection data and limited geological sampling. Most of the basin is a structurally simple downwarp that formed as a fore-arc basin between an Eocene-early Miocene volcanic arc in the southwest and an outer-arc high in the northeast. The basin contains up to 5 km of strata interpreted as early Miocene and possibly Oligocene volcaniclastics, early- late Miocene shelf carbonates, late Miocene and Pliocene bathyal chalk s and volcaniclastics, and Pleistocene-Recent sediments ranging from terrestrial conglomerates to hemipelagic oozes. In the east, Plio-Pleistocene volcanism has formed islands and greatly disturbed the older strata. Petroleum prospects offshore appear to be moderate. Early-late Miocene clastic and carbonate source rocks are thought to be present, and presumed reefal bodies may form traps within a thick and deeply buried early-late Miocene platform carbonate sequence, similar to the widespread Lelet Limestone exposed on New Ireland.