TY - JOUR
T1 - Petrography, geochemistry, and tectonics of a rifted fragment of Mainland Asia
T2 - Evidence from the Lasala Formation, Mindoro Island, Philippines
AU - Concepcion, R. A.B.
AU - Dimalanta, C. B.
AU - Yumul, G. P.
AU - Faustino-Eslava, D. V.
AU - Queaño, K. L.
AU - Tamayo, R. A.
AU - Imai, A.
N1 - Funding Information:
Acknowledgments We acknowledge the financial support given by the Department of Science and Technology–Philippine Council for Industry and Energy Research and Development (DOST–PCIERD) and the University of the Philippines–National Institute of Geological Sciences (UP–NIGS). Logistic and field support was extended by the provincial government of Mamburao, Occidental Mindoro. Special thanks to Prof. Mei–Fu Zhou of The University of Hongkong, Prof. Tsanyao Frank Yang of National Taiwan University, Dr. Allan Gil Fernando of UP-NIGS, and Mr. Raymond Ancog of MGB for the analysis of the samples. Productive discussions from members of the Rushurgent Working Group of the National Institute of Geological Sciences are acknowledged with thanks.
PY - 2012/1
Y1 - 2012/1
N2 - Petrological and geochemical investigations of the sedimentary Lasala formation in northwest Mindoro, Philippines, offer new insights into the origin of this geologically contentious region. Mindoro island's position at the boundary between Sundaland and the Philippine Mobile Belt has led to variable suggestions as to how much of it is continent derived or not. The Eocene Lasala formation overlies the Jurassic Halcon metamorphics, a regionally metamorphosed suite generally thought to have formed as a result of arc-continent collision processes. The sedimentary formation consists mainly of sandstones and shales interbedded with mudstones, basalt flows, and subordinate limestones and conglomerates. Petrographic information on the Lasala clastic rocks demonstrates a uniform framework composition that is predominantly quartzose. Major oxide, trace element abundances, and various elemental ratios similarly impart a strongly felsic signature. These characteristics are taken to indicate a chiefly continental, passive margin derivation and deposition of the Lasala sediments during the Eocene. The weak indication of active margin influence is suggested to be an inherited signature, supported by paleogeographic models of the southeastern Asian margin area during the pre-Cenozoic.
AB - Petrological and geochemical investigations of the sedimentary Lasala formation in northwest Mindoro, Philippines, offer new insights into the origin of this geologically contentious region. Mindoro island's position at the boundary between Sundaland and the Philippine Mobile Belt has led to variable suggestions as to how much of it is continent derived or not. The Eocene Lasala formation overlies the Jurassic Halcon metamorphics, a regionally metamorphosed suite generally thought to have formed as a result of arc-continent collision processes. The sedimentary formation consists mainly of sandstones and shales interbedded with mudstones, basalt flows, and subordinate limestones and conglomerates. Petrographic information on the Lasala clastic rocks demonstrates a uniform framework composition that is predominantly quartzose. Major oxide, trace element abundances, and various elemental ratios similarly impart a strongly felsic signature. These characteristics are taken to indicate a chiefly continental, passive margin derivation and deposition of the Lasala sediments during the Eocene. The weak indication of active margin influence is suggested to be an inherited signature, supported by paleogeographic models of the southeastern Asian margin area during the pre-Cenozoic.
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U2 - 10.1007/s00531-011-0643-5
DO - 10.1007/s00531-011-0643-5
M3 - Article
AN - SCOPUS:84855299316
VL - 101
SP - 273
EP - 290
JO - International Journal of Earth Sciences
JF - International Journal of Earth Sciences
SN - 1437-3254
IS - 1
ER -