Journal article

Adakites in the Truong Son and Loei fold belts, Thailand and Laos: Genesis and implications for geodynamics and metallogeny

Teera Kamvong, Khin Zaw, Sebastien Meffre, Roland Maas, Holly Stein, Chun-Kit Lai



LA-ICP-MS U-Pb zircon dating reveals that the Phu Kham adakites in the Truong Son Belt were emplaced during the Late Carboniferous (ca. 306 to 304Ma), whereas the Puthep 1 (PUT 1) adakites in the Loei Fold Belt were formed during the Middle Triassic (ca. 244 to 241Ma). These rock formation ages are largely coeval to Re-Os molybdenite ages (Phu Kham: ca. 304Ma; PUT 1: ca. 246Ma), suggesting close temporal links between adakite formation and copper-gold mineralization. New geochemical results show that the Phu Kham and PUT 1 adakites are characterized by low HREE and Y contents, but elevated LREE, Sr, Sr/Y, and La/Yb values. In addition, the two adakites have relatively high 143Nd/144Nd ratios..

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Awarded by US National Science Foundation

Funding Acknowledgements

This work was part of the senior author's PhD research and was financially supported by the Australian Research Council (ARC) Linkage Grant "Geochronology, Metallogenesis and Deposit Styles of Loei Fold Belt in Thailand and Laos PDR Project (2004-2007)" with Kingsgate Consolidated Ltd., Oxiana Ltd. (now MMG), and PanAust Ltd., and the Industry-CODES funded "Ore Deposits of SE Asia (2008-2010)" Project, both led by Khin Zaw, and grants from the Society of Economic Geologists. We also acknowledge IPRS and CODES PhD scholarships from the University of Tasmania. The US National Science Foundation (EAR-0451693) partially supported the Re-Os analytical work. We thank PanAust Ltd. for logistical support during the fieldwork, together with Phil Robinson, Sarah Gilbert and Katie McGoldrick for technical assistance with XRF and ICP-MS analyses. Special thanks are due to Derek Wyman for reviewing the earlier version of the manuscript, together with the precious recommendations by David Lentz and Dan Marshall.