Porphyry copper assessment of East and Southeast Asia: Philippines, Taiwan (Republic of China), Republic of Korea (South Korea), and Japan

Hammarstrom, Jane M.; Bookstrom, Arthur A.; Demarr, Michael W.; Dicken, Connie L.; Ludington, Steve; Robinson, Gilpin R.; Zientek, Michael L.

doi:10.3133/sir20105090p

Cited by 7 publications

(8 citation statements)

References 27 publications

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“…It is possible, as suggested by Qin and Ishihara () and Hammarstrom et al . (), that PCD may be present but are too deep (>1 km) to have been discovered.…”

Section: Discussionmentioning

confidence: 99%

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Testing the Plagioclase Discriminator on the GEOROC Database to Identify Porphyry‐Fertile Magmatic Systems in Japan

et al. 2018

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Despite showing favorable geology, there are no known porphyry‐type deposits in Japan. This, therefore, provides an ideal porphyry‐“barren” case area on which to test the recently developed plagioclase‐based discriminator for porphyry‐“fertile” calc‐alkaline systems. The discriminator was applied to plagioclase data for Japan in the online GEOROC database for convergent margin settings. Of the 3933 data points available, and considered reliable, 91% fall in the “barren” field, which compares with 73% for equivalent data worldwide. “Fertile” signatures in certain parts of Kyushu and central Honshu should be further investigated, as well as areas where there are magnetite‐series magmatic systems with elevated whole‐rock Sr/Y but for which there are currently little or no plagioclase data (SW‐, N‐central‐, and NE‐Honshu). Why the Japanese arcs appear to show anomalously poor potential for porphyry deposits compared with other arcs worldwide, including Western Luzon, is as yet unclear but possibly relates to tectonic factors or the nature of the magmatic source or because melt PH2O in many of the magmatic systems was too low, as suggested from low average excess Al in plagioclase.

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“…It is possible, as suggested by Qin and Ishihara () and Hammarstrom et al . (), that PCD may be present but are too deep (>1 km) to have been discovered.…”

Section: Discussionmentioning

confidence: 99%

“…Despite having discussed many of these reasons for the lack of PCD in Japan, both Qin and Ishihara () and Hammarstrom et al . () concede that they may well be present at depth (>1 km), possibly buried beneath thick sequences of volcanic rocks.…”

Section: Introductionmentioning

confidence: 99%

Testing the Plagioclase Discriminator on the GEOROC Database to Identify Porphyry‐Fertile Magmatic Systems in Japan

et al. 2018

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“…), in which gneissose intrusions are hosted by high‐ T/P metamorphic rocks, and coeval volcanic rocks are absent (Nakajima, ), is far too deeply eroded for porphyry Cu preservation. In contrast, Plio‐Pleistocene volcanoes throughout Japan are typically too shallowly eroded to expose any porphyry Cu deposits with which they may be associated (Hammarstrom et al , ).…”

Section: Regional Factors Influencing Porphyry Cu Potentialmentioning

confidence: 99%

“…Andesitic–dacitic stratovolcanoes and dome complexes that either immediately pre‐dated, accompanied, or concluded the caldera flare‐ups offer possible sites, although most Pliocene and Quaternary examples, including those generated since ~3.5 Ma in the NE Japan arc (Sato, ; Yoshida et al , ; Fig. b) and the post‐2 Ma adakites in SW Japan (Shibata et al , ), are unlikely to have undergone sufficient erosion to reveal the porphyry Cu environment (Ishihara, ; Hammarstrom et al , ). Indeed, some are still underlain by active magmatic‐hydrothermal systems (Hedenquist et al , ).…”

Section: Porphyry Cu Potential Of Japan and South Koreamentioning

confidence: 99%

“…Sato (), however, considered the absence to be a result of the chemically reduced crust existing beneath much of Japan, whereas Hattori () attributed it to a reduced mantle wedge consequent upon an absence of carbonate sediments on the subducted oceanic plate. In contrast, Yang and Bodnar (), using melt and fluid inclusion evidence, concluded that the Cretaceous–Paleogene intrusions in SE Korea were too deeply eroded to preserve any porphyry Cu deposits that might once have existed there, a concept that was further supported for both SE Korea and the Inner Zone of SW Japan by Hammarstrom et al ().…”

Section: Introductionmentioning

confidence: 99%

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Why No Porphyry Copper Deposits in Japan and South Korea?

Sillitoe¹

2018

Resource Geology

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This analysis concludes that there is little realistic likelihood of discovering large, high‐grade porphyry Cu deposits in Japan and South Korea because of an unusual combination of geological factors. First, weak inter‐plate coupling, trench retreat, and extension – a tectonic regime unfavorable for porphyry Cu formation – appears to have characterized the convergent margin during much of Cretaceous through Neogene time. Second, Cretaceous through Quaternary magmatism involved widespread ash‐flow caldera development, a volcanic style that suppresses porphyry Cu formation because the all‐important Cu‐bearing magmatic fluids – if present – would be explosively discharged during silicic ignimbrite eruption and lost to the atmosphere. Third, due to the trench retreat, crustal profiles beneath Japan are dominated by accretionary complexes containing chemically reduced lithologies, which decrease the redox state of subduction‐related magmas during their ascent. The most reduced intrusions belong to the ilmenite‐series, which may lock up chalcophile elements at depth and produce magmatic fluids that are incapable of transporting the Cu required for significant porphyry deposit formation. Fourth, many of the caldera‐related magmatic rocks, including the principal intrusions, are not only derived by partial melting of reduced crust but are commonly also highly fractionated; hence, any associated mineralization tends to be Mo ± W‐rich rather than Cu dominated. Fifth, intrusive rocks with high Sr/Y, typical of hydrous magmas responsible for porphyry Cu belts worldwide, appear to be present only locally. Sixth, two important magmatic and metallogenic tracts in Japan, the Kuroko‐bearing Green Tuff belt and Kitami low‐sulfidation epithermal Au region, are characterized by bimodal magmatism, which worldwide is compositionally unsuited to porphyry Cu generation. Seventh, the Pliocene‐Quaternary andesitic–dacitic volcanoes that could be the surface expressions of porphyry Cu systems are mostly too shallowly eroded to reveal underlying deposits should they exist. Consequently, few magmatic suites in Japan and South Korea provide propitious environments for porphyry Cu exploration, with the last hope believed to lie at depth below late Miocene–Pliocene advanced argillic lithocaps, several of which contain relatively minor high‐sulfidation epithermal Au mineralization. However, even there, the reduced crust may have militated against effective Cu transport into the porphyry environment. The magmatic and metallogenic factors that downgrade the porphyry Cu potential of Japan and South Korea are believed to be equally applicable to other subduction‐related magmatic arc segments worldwide.

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A System Dynamics Assessment of the Supply of Molybdenum and Rhenium Used for Super-alloys and Specialty Steels, Using the WORLD6 Model

Sverdrup

Ólafsdóttir

Ragnarsdottir

et al. 2018

Biophys Econ Resour Qual

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Porphyry copper assessment of East and Southeast Asia: Philippines, Taiwan (Republic of China), Republic of Korea (South Korea), and Japan

Cited by 7 publications

References 27 publications

Testing the Plagioclase Discriminator on the GEOROC Database to Identify Porphyry‐Fertile Magmatic Systems in Japan

Testing the Plagioclase Discriminator on the GEOROC Database to Identify Porphyry‐Fertile Magmatic Systems in Japan

Why No Porphyry Copper Deposits in Japan and South Korea?

A System Dynamics Assessment of the Supply of Molybdenum and Rhenium Used for Super-alloys and Specialty Steels, Using the WORLD6 Model

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