Provenance and tectonic setting of Miocene clastic sedimentary rocks from the Baguio District, Luzon, Philippines : Evidence from major and trace element geochemistry

Major and trace element geochemistry of Miocene sandstones and shales from the Baguio District, Luzon, Philippines have been analyzed to determine their provenance and tectonic setting. Major element discrimination plots (e.g. SiO2-K2O/Na2O) reveal mafic volcanic arcs as possible source rocks. Elemental ratios critical of provenance (Th/Sc, Zr/Sc) mainly reveal an active continental margin signature for the Zigzag Formation and an oceanic island arc for the Klondyke Formation. These results support earlier studies that the Baguio District had evolved from a marginal basin environment to a mature island arc setting.