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Quantifying exhumation at the giant Pulang porphyry Cu-Au deposit ssing U-Pb-He dating

Citation

Leng, C-B and Cooke, DR and Hou, Z-Q and Evans, NJ and Zhang, X-C and Chen, WT and Danisik, M and McInnes, BIA and Yang, J-H, Quantifying exhumation at the giant Pulang porphyry Cu-Au deposit ssing U-Pb-He dating, Economic Geology and The Bulletin of The Society of Economic Geologists, 113, (5) pp. 1077-1092. ISSN 0361-0128 (2018) [Refereed Article]


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Licensed under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) https://creativecommons.org/licenses/by-nc/4.0/

DOI: doi:10.5382/econgeo.2018.4582

Abstract

The Triassic Pulang porphyry Cu-Au deposit, located in the South Yidun terrane, is the oldest and one of the largest porphyry deposits in the southeastern Tibetan Plateau. The mineralization occurs mostly in the potassic alteration zone of the Pulang intrusive complex. U-Pb-He triple dating, namely apatite (U-Th)/He, zircon U-Pb, and zircon (U-Th)/He dating, together with inverse thermal modeling, reveals that the Pulang complex was emplaced at a paleodepth of 5.0 to 6.5 km at 215 2 Ma. The deep-level emplacement of the complex, coupled with the episodic replenishment of the magma chamber, gave rise to the establishment of a prolonged magmatic-hydrothermal system at Pulang. Although a range of single-grain zircon and apatite (U-Th)/He ages were obtained on each sample, the weighted mean zircon and apatite (U-Th)/He ages vary systematically with elevation, defining a multistage cooling/denudation history at Pulang. Specifically, three phases of cooling were recognized from inverse thermal modeling, including rapid cooling (80120C/m.y.) in the Late Triassic, moderate cooling (35C/m.y.) from the Late Triassic to Early Cretaceous, and a protracted slow cooling period (50 m.y.) of extremely slow cooling and erosion at Pulang could be related to the formation and preservation of a peneplain on the southeastern Tibetan Plateau since the Late Cretaceous. A relict peneplain thus signifies a favorable tectonic environment for the preservation of ancient porphyry systems worldwide.

Item Details

Item Type:Refereed Article
Keywords:porphyry, copper, uplift, exhumation, U-Pb-He dating
Research Division:Earth Sciences
Research Group:Geology
Research Field:Ore Deposit Petrology
Objective Division:Mineral Resources (excl. Energy Resources)
Objective Group:Other Mineral Resources (excl. Energy Resources)
Objective Field:Mineral Resources (excl. Energy Resources) not elsewhere classified
Author:Cooke, DR (Professor David Cooke)
ID Code:128160
Year Published:2018
Funding Support:Australian Research Council (CE0561595)
Deposited By:CODES ARC
Deposited On:2018-09-06
Last Modified:2018-10-01
Downloads:12 View Download Statistics

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