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Rare Earth Element Geochemistry of the Zigzag - Klondyke Sedimentary Rock Formations: Clues to the Evolution of the Baguio Mineral District (Luzon), Philippines |
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| Authors: | Tomas A Tam III Graciano P Yumul Jr Estephanie Gera L Ramos Carla B Dimalanta Mei-Fu Zhou Shigeyuki Suzuki |
| Institution: | Tectonics and Geodynamics Group, National Institute of Geological Sciences, College of Sxience, University of the Philippines, Diliman, Quezon City, Philippines [e-mail: ];Department of Earth Sciences, Okayama University, Okayama, Japan;Philippine Council for Industry and Energy Research and Development, Department of Science and Technology, Bicutan, Taguig, Metro Manila, Philippines;Department of Earth Sciences, University of Hong Kong, Hong Kong, China |
| Abstract: | Abstract. Petrographic analysis of the Oligocene-Miocene Zigzag Formation and Miocene Klondyke Formation of the Baguio Mineral District reveals a transitional arc source for the former and an undissected arc source for the latter. Whole rock geochemistry of these sedimentary rock formations show affiliation of the Zigzag Formation to active continental margin whereas the Klondyke Formation appears to have been derived from an oceanic island arc source. A different aspect of the geology of the district is further gleaned from the whole rock rare earth element geochemistry of these rocks. Samples from the Zigzag Formation are characterized by higher REE concentrations compared to the Klondyke Formation samples. The REE data indicate that the sedimentary rocks of the Klondyke Formation had geochemically-less fractionated igneous lithologies as their progenitor whereas the older Zigzag Formation was derived from a more differentiated source. This new set of information contributes to the understanding of the evolution of this district from a marginal basin to an island arc setting. |
| Keywords: | sedimentary formations REE geochemistry Baguio Philippines |