|
岩石学报 2009
Geochronology and geochemistry of granites in the Tengliang area, western Yunnan: Tectonic implication
|
Abstract:
The granitoids outcropped extensively in the form of batholiths, stocks, and dikes in the Tengchong-Lianghe area, east of Eastern Himalaya Syntaxis. The plutons (so called Tengliang granites) are composed of Guyong Group and Binglanjiang Group. The Tengliang granites are distributed along a number of NNE-extending faults. They show some shearing features related to syn-tectonic intrusion and dyke-developing emplacement. SHRIMP zircon U-Pb dating reveals two episodes of magmatism of Late Cretaceous (76~67Ma; Guyong Group) and Early Paleocene (53Ma; Bingliangjiang Group). The Tengliang granites are composed of biotite monzonogranite, biotite perthite granite, pegmatite, with no typical peraluminous minerals. Characterized by high-potassium, peraluminous to strongly peraluminous, they were generated from lower to middle crust by partial melting of metapelite. The partial melting was induced by crustal thickening related to the subduction of Neo-Tethyan plate and subsequent collision between India and Asia continents. It is suggested that the Tengliang granites are the eastward extending part of Gandese batholith, but have different genesis.