Buruanga peninsula and Antique Range: Two contrasting terranes in Northwest Panay,Philippines featuring an arc–continent collision zone |
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| Authors: | Lawrence R Zamoras Mary Grace A Montes Karlo L Queaño Edanjarlo J Marquez Carla B Dimalanta Jillian Aira S Gabo Graciano P Yumul Jr |
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| Institution: | 1. Philex Mining Corporation, Pasig City, Philippines (e‐mail: rwgmails@yahoo.com),;2. Tectonics and Geodynamics Group, National Institute of Geological Sciences, College of Science, University of the Philippines, Diliman, Quezon City, Philippines,;3. Mines and Geosciences Bureau, Diliman, Quezon City, Philippines,;4. Department of Physical Sciences and Mathematics, University of the Philippines, Manila, Philippines, and;5. Department of Science and Technology, Bicutan, Taguig, Philippines |
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| Abstract: | Alternating chert–clastic sequences juxtaposed with limestone blocks, which are units typical of accretionary complexes, constitute the Buruanga peninsula. New lithostratigraphic units are proposed in this study: the Unidos Formation (Jurassic chert sequence), the Saboncogon Formation (Jurassic siliceous mudstone–terrigenous mudstone and quartz‐rich sandstone), the Gibon Formation (Jurassic(?) bedded pelagic limestone), the Libertad Metamorphics (Jurassic–Cretaceous slate, phyllite, and schist) and the Buruanga Formation (Pliocene–Pleistocene reefal limestone). The first three sedimentary sequences in the Buruanga peninsula show close affinity with the ocean plate stratigraphy of the North Palawan terrane in Busuanga Island: Lower–Middle Jurassic chert sequences overlain by Middle–Upper Jurassic clastics, juxtaposed with pelagic limestone. Moreover, the JR5–JR6 (Callovian to Oxfordian) siliceous mudstone of the Saboncogon Formation in the Buruanga peninsula correlates with the JR5–JR6 siliceous mudstone of the Guinlo Formation in the Middle Busuanga Belt. These findings suggest that the Buruanga peninsula may be part of the North Palawan terrane. The rocks of the Buruanga peninsula completely differ from the Middle Miocene basaltic to andesitic pyroclastic and lava flow deposits with reefal limestone and arkosic sandstone of the Antique Range. Thus, the previously suggested boundary between the Palawan microcontinental block and the Philippine Mobile Belt in the central Philippines, which is the suture zone between the Buruanga peninsula and the Antique Range, is confirmed. This boundary is similarly considered as the collision zone between them. |
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| Keywords: | arc– continent collision Buruanga peninsula Busuanga Island chert– clastics– limestone sequence North Palawan terrane ocean plate stratigraphy |
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