Bulletin of the Geological Society of Malaysia, Volume 43, Dec. 1999, pp. 77 – 84
1Rushurgent Working Group, National Institute of Geological Sciences, College of Science, University of the Philippines, Diliman, Quezon City, Philippines
2Ocean Research Institute, University of Tokyo, Tokyo, Japan
Abstract: The different volcanoes and volcanic centers in Central Luzon, Philippines define two volcanic chains – the Western and Eastern Volcanic Chains. The Western Volcanic Chains include volcanic rocks generated in the forearc and main volcanic arc regions with respect to the Manila Trench. The Eastern Volcanic Chains, on the other hand, were extruded on the back arc side. Across- and along-arc variations are present in these two volcanic chains. These variations can be attributed to the interplay of several geochemical processes that occurred in source regions that manifest island arc affinity. An adakite-tholeiitic/calc-alkaline-adakitic rock across-arc variation is recognized in Central Luzon.