Re-Os isochron ages for arsenopyrite from Carlin-like gold deposits in the Yunnan-Guizhou-Guangxi 'golden triangle', southwestern China

摘要

The Yunnan-Guizhou-Guangxi "golden triangle" is considered to be one of the regions hosting Carlin-like gold deposits in China. Gold deposits in this region can be grouped into lode type that are controlled by faults and layer-like type controlled by stratigraphy. Arsenopyrite is one of the major gold-bearing minerals in these deposits. Rhenium-Os isotopic dating of arsenopyrite from the lode type Lannigou and Jinya and the layer-like type Shuiyindong gold deposits yields isochron ages of 204 ±19 Ma, 206 ± 22 Ma, and 235 ± 33 Ma, respectively. The data suggest that the Carlin-like gold deposits formed in Late Triassic to Early Jurassic, which is clearly earlier than the ca. 100-80 Ma acid to ultra-basic magmatism in this part of southwestern China. The ages are consistent with ore formation during a period of post-collisional lateral transpression, which is similar to that of the Carlin-like gold deposits in western Qinling of China, but quite different from Carlin-type gold deposits in Nevada, U.SA