Geochronology, Geochemistry and Petrogenesis of Granites in Weixi-Deqin, West Yunnan
GAO Rui
XIAO Long
HE Qi
YUAN Jing
NI Ping-ze
DU Jing-xi
Abstract：There is still much dispute over the exact subduction and collision time of Jinshajiang arc-basin system, which reveals geological evolution history of the paleo-Tethys in West China. This study provides chronological, petrological, and geochemical data of Congka and Yangla granitoid plutons that are situated on the western margin of Jinshajiang suture zone but poorlystudied in Deqin-Weixi area, Yunnan Province. The Yangla granitoid complex is divided into granodiorite and monzonite. LAICP-MS zircon dating results are 229. 6 Ma (Yangla granodiorite), 232 Ma (Gongka granodiorite) and 261 Ma (Yangla monzonite), respectively. Yangla monzonites, showing O-adakitie affinity, was generated through partial melting of oceanic slab when subducting, probably subjected to metasomatism of the mantle wedge. Gongka granodiorites and Yangla granodiorites were derived from partial melting of lower crustal rocks. In general, we conclude that the subduction started from Middle Permian to Late Permian and the collision started in Late Permian and terminated in early Middle Triassic.
Keywords：paleo-Tethysadakitic rockI-type granitegeochronologygeochemistrySr-Nd isotopepetrogenesis.
Publication Date：2010-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：15( 186-200 )