ABSTRACT: Potential Pliocene Reef Traps in the Iron Bottom Basin, Solomon Islands
Howard Johnson, John Pflueger
The Iron Bottom Basin is situated in Iron Bottom Sound, north of Honiara, Guadalcanal, Solomon Islands. It is the most southerly subbasin of the central Solomons Trough -- a large, composite, intra-arc basin that contains a maximum sedimentary thickness of about 4.5 km of late Oligocene to Quaternary strata. Sediments in the Iron Bottom basin were probably derived from mafic igneous and metamorphic rocks on Guadalcanal, but detrital carbonate and reef limestone are probably subordinate constituents.
Seismic mound-like anomalies in the nearshore area (water depth 550 to 650 m) of Iron Bottom Sound display many of the characteristics of buried reefs. They occur at two stratigraphic levels and are interpreted to be Pliocene shelf-edge reefs and a patch reef. At each level the shelf-edge reefs cover an area more than 6 km by 3 km and are up to about 200 m thick. They are overlain by about 1 km of stratified sediments and form potential traps for hydrocarbons, if generation and migration have occurred.
AAPG Search and Discovery Article #90097©1990 Fifth Circum-Pacific Energy and Mineral Resources Conference, Honolulu, Hawaii, July 29-August 3, 1990