Geochronology and Tectonic Evolution of the Lincang Batholith in Southwestern Yunnan, China

Abstract EN

Geochronological research of the Lincang Batholith is one key scientific problem to discuss the tectonic evolution of the Tethys.

Two granitic specimens were selected from the Mengku-Douge area in the Lincang Batholith to perform the LA-ICPMS Zircon U-Pb dating based on thorough review of petrological, geochemical, and geochronological data by the former scientists.

Rock-forming age data of biotite granite specimen from Kunsai is about 220 Ma, the Norian age.

However, the west sample from Mengku shows 230 Ma, the Carnian age.

The later intrusion in Kunsai area located east to the Mengku area shows directly their uneven phenomena in both space and time and may indirectly reflect the space difference of the contraction-extension transformation period of the deep seated faults.

Considering the former 40Ar/39Ar data and the outcrop in Mengku, the Lincang Batholith should have experienced one tectonic exhumation and regional subsidence cycle.

The regional subsidence cycle has close relations to the expansion of the Meso Tethys.