| Abstract: |
The mineral concentrations left on the east flank of the Central Range by the Paleozoic-to-Mesozoic episode of metallogeny are mainly cupriferous pyrite deposits of the stratabound massive sulfide type, owing their genesis to submarine volcanism. Added to this mineral belt are pegmatitic deposits due to subsequent granitization. The Cenozoic episode of metallogeny gave birth in the Coastal Range to porphyry copper deposits in the Miocene and in the Taipei-Chilung volcano area to epithermal gold and copper deposits in the Pleistocene, both being genetically related to andesitic volcanism. Each mineral belt lies exactly on a magmatic arc and is understandably the high-level manifestation of the plate subduction deep beneath. Clearly, the repeated mineralization in Taiwan was motivated by the to-and-fro subduction of the Philippine Sea plate, each time of a part of its northwest corner. The islandÂ’s metallogenic framework fits neatly in, and is actually an ore-geologistsÂ’ version of, the plate-tectonic model of the region. In a broader plate-tectonic perspective, the Central Range mineral belt was a part of southeastern China during the Mesozoic metallogenic epoch and the Coastal Range mineral belt a part of Luzon during the Cenozoic. Despite its favourable close connexions with these ore-rich regions, Taiwan seems not endowed with much metallic wealth. The limited distribution of ore deposits on the present-day surface of the island may be attributed largely and simply to the very narrow exposure of the newly uplifted mineral belts from a thick overburden or from the deep sea.
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