The Philippines are essentially composed of a basement of metamorphosed sedimentary and volcanic rocks of unknown age, cut by ultrabasic to intermediate plutonic intrusives, and a thick upper Tertiary marine sequence. Continuity of structure, geographic position, and similarities of Tertiary development indicate a close relationship between the Philippine islands and the Indonesian archipelago, an important oil-producing region of the Far East. Although exploration to date has failed to develop commercial production and surface indications are not extensive, prospective fields (mainly intra-island basins) are believed to exist in areas in which geosynclinal conditions of accumulation were approached during Miocene and Pliocene time.

You do not currently have access to this article.