Fission track evidence on thermal history of Jiama polymetallic ore district,Tibet  

作　　者：袁万明 侯增谦 李胜荣 王世成 

出　　处：《Science China Earth Sciences》2001年第S1期139-145,共7页中国科学（地球科学英文版）

基　　金：the National Natural Science Foundation of China (Grant No.40072068) and the President Fund of the Chinese Academy of Sciences (Grant No. 99-775), and Laboratory of Nuclear Analysis Technique, CAS.

摘　　要：It is a new attempt to study thermal evolution related to mineralization using the fission track (FT) method. Apatite and zircon fission track data are reported for 6 samples collected from Jiama ore district as well as its periphery. The FT ages of apatites in the ore district are (16.1±0.9) Ma and (18.8±1.1) Ma and reflect the age of late period of hydrothermal mineralizing event. Apatite FT age of (22.0±4.3) Ma and zircon FT age of (20.9±2.0) Ma are related to the early period of mineralization. Another zircon FT age of (341.6±79.1) Ma, inheriting mineral source characteristic, has no connection with the mineralization. Based on the thermal history analysis, the mineralization began before 25-22 Ma. Cooling rate in the ore district is 5-6℃/Ma averagely, in which a slow cooling occurred at 90-80℃. About 2.7 km has been denuded and the denudation rate is higher than the uplifting rate.It is a new attempt to study thermal evolution related to mineralization using the fission track (FT) method. Apatite and zircon fission track data are reported for 6 samples collected from Jiama ore district as well as its periphery. The FT ages of apatites in the ore district are (16.1±0.9) Ma and (18.8±1.1) Ma and reflect the age of late period of hydrothermal mineralizing event. Apatite FT age of (22.0±4.3) Ma and zircon FT age of (20.9±2.0) Ma are related to the early period of mineralization. Another zircon FT age of (341.6±79.1) Ma, inheriting mineral source characteristic, has no connection with the mineralization. Based on the thermal history analysis, the mineralization began before 25-22 Ma. Cooling rate in the ore district is 5-6℃/Ma averagely, in which a slow cooling occurred at 90-80℃. About 2.7 km has been denuded and the denudation rate is higher than the uplifting rate.

关 键 词：: FISSION track thermal history JIAMA POLYMETALLIC ore. 

分 类 号：P597[天文地球—地球化学]