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Porphyry and epithermal deposits and 40Ar/39Ar geochronology of the Baguio District, Philippines
Citation
Waters, PJ and Cooke, DR and Gonzales, RI and Phillips, D, Porphyry and epithermal deposits and 40Ar/39Ar geochronology of the Baguio District, Philippines, Economic Geology, 106, (8) pp. 1335-1363. ISSN 0361-0128 (2011) [Refereed Article]
Copyright Statement
Statement: © 2011 Society of Economic Geologists, Inc. Society of Economic Geologists, 7811 Shaffer Parkway, Littleton, CO 80127, USA
DOI: doi:10.2113/econgeo.106.8.1335
Abstract
Recent exploration has led to the discovery of several new porphyry copper-gold and skarn prospects in the western Baguio district. Mineralization was preceded by the intrusion of a suite of hornblende megacrystic andesite dikes in the central part of the district from 4.55 ± 0.15 to 3.45 ± 0.19 Ma. Porphyry copper-gold and skarn deposits at Black Mountain and Mexico, on the western side of the district, formed between 3.09 ± 0.15 and 2.81 ± 0.24 Ma. The Santo Tomas II Cu-Au-(Pd) porphyry deposit was emplaced into the central southern part of the district at about 1.5 Ma, based on secondary biotite 40Ar/39Ar ages of 1.48 ± 0.05 Ma and 1.47 ± 0.05 Ma. On the eastern side of the district, porphyry-style mineralization at the Hartwell and Ampucao porphyry Cu-Au prospects returned 40Ar/39Ar ages of 1.09 ± 0.10 and 0.51 ± 0.26 Ma, respectively.
Quartz-carbonate-base metal sulfide style epithermal gold-silver veins are well-developed on the eastern side of the Baguio district, and crosscut porphyry-style mineralization at the Acupan, Baguio gold and Nugget Hill deposits. Epithermal veining is inferred to have occurred in the past million years, based on a reported K-Ar age determination of 0.65 ± 0.07 Ma from the Acupan gold mine. A large advanced argillic alteration zone (the Baguio lithocap) crops out in the northwest part of the district, and formed between 1.4 and 0.9 Ma, based on previous K-Ar dating.
Pliocene-Pleistocene mineralization in the Baguio district was triggered by the east-directed subduction of the Scarborough Ridge. Ridge subduction caused the subduction angle along the Manila Trench beneath northern Luzon to decrease, which facilitated crustal thickening and exhumation. Ridge subduction also promoted the development of northwest-trending faults in the upper plate that interacted with major arc-parallel north- and arc-normal northeast-trending fault sets associated with the Philippine fault system. Fertile magmas were emplaced into transtensional strike-slip relay basins, resulting in the accumulation of more than 35 Moz of gold and several million tonnes of copper over approximately 3 m.y.
Item Details
Item Type: | Refereed Article |
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Keywords: | porphyry copper deposites Baguio Philippines geochronology |
Research Division: | Earth Sciences |
Research Group: | Geology |
Research Field: | Geochronology |
Objective Division: | Mineral Resources (Excl. Energy Resources) |
Objective Group: | Mineral exploration |
Objective Field: | Copper ore exploration |
UTAS Author: | Cooke, DR (Professor David Cooke) |
ID Code: | 74878 |
Year Published: | 2011 |
Web of Science® Times Cited: | 55 |
Deposited By: | Centre for Ore Deposit Research - CODES CoE |
Deposited On: | 2011-12-14 |
Last Modified: | 2019-02-20 |
Downloads: | 5 View Download Statistics |
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