HE Li1,2，ZHU Xiao-qing1*，WANG Fu-dong3，LI Xiao-xia1,2， SHENG Xiang-yuan1,2
（1. State Key Laboratory of Ore Deposit Geochemistry，Institute of Geochemistry，Chinese Academy of Sciences，Guiyang，550002，China；
2. Chinese Academy of Sciences University，Beijing，101408，China；
3. College of Environmental and Resource Sciences，Southwest University of Science and Technology，Mianyang，621010，China）
Abstract: Emeishan basalt copper deposits are similar to Keweenaw copper deposits. The native copper deposit in amygdaloidal basalt which we called the “Amygdule -type” native copper ore rock, is one of the important components of Emeishan basalt copper deposits. The studies of ore minerals typomorphic characteristics, mineral assemblages and exsolution texture show that the “Amygdule -type” native copper deposits arevolcanic hydrothermal ore deposits thatformed in low-temperature reducing environment, significantly, the mineralization occurs in the hydrothermal stage, the dormant period or the terminal period of magmatism. The mineral sequence is as the order of copper→ bornite，chalcocite，chalcopyrite→cuprite，tenorite，malachite. Bitumen is generated almost simultaneously as the native copper，and provides a kind of strong reducing environment for the deposition of the native copper and copper sulfides. The temperature range of copper is defined as 290～－225 ℃ by the forming temperature of bitumen and the exsolution temperature of bornite-chalcocite.
Keywords: native copper; amygdaloidal basalt; mineral assemblage; exsolution texture; Emeishan
ACTA MINERALOGICA SINICA Vol. 37, No. 6, 2017, Page 717-724