Features resulting from the interplay of arc magmatism, ophiolite accretion, ocean basin closure and other subsequent tectonic processes are preserved in the Philippine island arc system. Subduction of ocean floor along the trenches surrounding the Philippines is a major factor in shaping the geologic history of this island arc system. Stress-strain relationships, as manifest in both the regional and local setting of the archipelago, are derived from the interaction of at least four major plates: Sundaland, Philippine Mobile Belt, Philippine Sea and, to a certain extent, the Indo-Australian plate. Collision zones in this island arc system are characterized by the involvement of oceanic bathymetric highs (seamounts, spreading ridge, submerged continental fragment). A major strike-slip fault, the Philippine Fault Zone, with compressional and extensional components, traverses the whole archipelago where all excess stress not accommodated by the surrounding trenches is taken up. Tholeiitic through adakitic to calc-alkaline rock suites characterize the different magmatic arcs. Exposed oceanic lithospheric fragments exhibit transitional mid-ocean ridge, back arc basin to island arc geochemical characteristics. The observed crustal thickness in the Philippines resulted from combined magmatic (volcanism) and amagmatic (ophiolite accretion) processes, with the former being the dominant factor.

Mindanao Island in the southern Philippines is made up of two blocks: the islandarc-related eastern-central Mindanao block and the continental Zamboanga Peninsula, which contains several ophiolitic bodies and m61anges. The Middle Miocene Siayan-Sindangan Suture Zone represents the tectonic boundary between the island-arc and continental blocks.

The Kingking deposit is a gold-rich porphyry copper deposit and the southernmost deposit at the eastern Mindanao mineralized belt, Philippines. It is underlain by Cretaceous -Paleogene sedimentary and volcanic rocks that are intruded by mineralized Miocene diorite porphyries and by barren Miocene -Pliocene dacite and diorite porphyries. The main alteration zones in the deposit are the inner potassic zone and the outer propylitic zone. The biotite-bearing diorite and hornblende diorite porphyries are the primary host rocks of mineralization. Two dominant copper minerals, bornite and chalcopyrite, which usually occur as fracture fi llings, are associated with fi ne crystalline quartz veinlet stockworks in the mineralized diorites. Minor secondary covellite, chalcocite and digenite are also observed. The primary Cu-Fe sulfi de phases initially deposited from ore fl uids consisted of bornite solid solution ( bnss ) and intermediate solid solution ( iss ), which decomposed to form the bornite and chalcopyrite. Peculiar bornite pods that are different from dissemination and are associated with volcanic rock xenoliths in biotite-bearing diorite porphyry are noted in a drill hole. These pods of bornite are not associated with quartz veinlet stockworks. Fluid inclusion analyses show three types of inclusions contained in Kingking samples: two-phase fl uid-rich and vapor-rich inclusions and polyphase hypersaline inclusions from porphyry-type quartz veinlet stockworks. The liquid -vapor homogenization temperatures (T H ) and the dissolution temperature of halite daughter crystals (T M ) from the polyphase hypersaline inclusions predominantly range from 400°C up to >500°C. The wide range of T H and T M may be due to heterogeneous trapping of variable ratios of vapor and brine. For some inclusions, T H > T M and in some cases, T H < T M , indicating that some of the brine was supersaturated or saturated with NaCl at the time of entrapment. Calculated salinity of the polyphase hypersaline inclusions ranges from 40 to 60% NaCl equivalent. Temperature and vapor pressure of mineralized fl uid were estimated to be 400°C and 16 MPa .

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High seismic activity in the Philippines originates from tectonic convergence related to surface and subsurface seismotectonic features. Based on earthquake data, the archipelago can be divided into the seismically-active Philippine Mobile Belt and the aseismic North Palawan Block. The latter represents a rifted continental fragment of the Eurasian margin that juxtaposed with the rest of island arc units in central Philippines. Earthquake hypocenter plots on planar and in vertical profiles show that the seismic events are associated with known seismotectonic features. In addition, data suggest that the collision zone between the North Palawan Block and the Philippine Mobile Belt is characterized by a decreased amount of hypocenters at >100 km depths. Although field evidence favors the presence of a subducted slab or slabs beneath western central Philippines, these are difficult to image using the present seismicity distribution dataset.