Free Web Hosting Provider - Web Hosting - E-commerce - High Speed Internet - Free Web Page
Search the Web

GEOLOGY AND MINERAL DEPOSITS OF THE PHILIPPINES  

by GABRIEL SANTOS, JR.


INTRODUCTION


GENERAL GEOLOGIC SETTING


MINERAL DEPOSITS AND GEOLOGICAL ENVIRONMENT


DEPOSITS RELATED TO OCEANIC-CRUST (OPHIOLITE)

The minerals of chromium and nickel-cobalt including the platinium group metals as well as massive sulfides of copper, zinc and iron are commonly associated with the ophiolite complexes. The 'Geological Map of the Philippines" (Bureau of Mines, 1963), shows the widespread distribution of the mafic-ultramafic rocks in the country paralled to the oceanic trenches and at or near some sections of the Philippine Fault. Large ophiolitic complexes composed mainly of peridiotite-diorite are found in the Zambales mountain range, western part of Sierra Madre Range, southeastern Samar, Dinagat island, Surigao, Davao Oriental, northern Tawi-Tawi. Smaller ultramafic masses are distributed in the other parts of the islands. The "Metallogenic Provinces" map (BM; PAEC; 1972) indicates the location of the important chromium-nickel deposits in the ultramafic bodies. Santos (1986) noted the occurrence of the Dasol massive copper-zinc-pyrite deposit in ophiolitic rock sequence dormantly pillow lavas and metavolcanics in Pangasinan. Balce et al., (1981) suggest the paired subduction zone-magmatic belts in the archipelago as the best indication of collision of several trench-arc systems. An example is the Manila Trench-Central Luzon volcanic belt. They also observed occurrences of unpaired ophiolite and magmatic belts. Other trench-arc systems are described in the JICA-MMAJ-MGB (1990) report. Table 1 lists the major mineral deposits and their locations associated with ophiolite complexes.


Table 1. Major mineral deposits and their locations related to ophiolite complexes.


DEPOSITS RELATED TO VOLCANIC OR MAGMATIC ARC