THE DEFLUIDIZATION OF THE ROCKS AND GENESIS OF GOLD DEPOSITS DURING DEFORMATION AND METAMORPHISM: AN EXAMPLE FROM THE JINPING MOUNTAIN  

作　　者：Li Sheng(Chengdu Institute of Geology and Mineral Resources, Chengdu, 610082,China) 

出　　处：《地学前缘》2000年第S1期411-412,共2页Earth Science Frontiers

摘　　要：The Jinping mountain region on the western margin of the Kang\|Dian axis is situated in the area bordered by the eastern margin of the Qinghai—Xizang Plateau on the west and the western margin of the Yangtze plate on the east, and consists of three\|layer structures: basement (Kang\|Dian axis), detachment zone (sliding surface of lateral extension and thrusting) and the overburden of the Jinping mountain nappe. The intense intracratonic deformation and metamorphism within the Kang\|Dian axis resulted in the activation, migration and enrichment of mineral elements and finally the formation of ore deposits in the Jinping mountain region. As for the Kang\|Dian axis as the crystalline and folded basement, the lower background values ((0 4～0 8)×10 -9 ) of the element Au don’t represent the initial contents, which have mostly been activated and moved away.. In the Lizhuang\|Lawo\|Bazhe zone as the detachment structural zone, the high er background values ((6～10)×10 -9 ) of the element Au don’t represent the initial contents as well, which have received more gold from the multistage ductile shear zones in the detachment zone. As a result of the lower degrees of deformation and metamorphism within the overburden of the Jinping mountain nappe, the lower temperatures and pressures are insufficient to activate and migrate the element Au; the Au contents available represent the initial Au contents ranging between 1 6 and 2×10 -9 , which are equal to the crustal clarke values from Li Tong and Dai Wentian. The activation and migration of the element Au are believed to be governed by the temperatures and transported media especially variable valent elements and their compounds (principally H 2O, Cl, CO 2 , S and Fe). The associated sediments are also correlated with the transported media especially the valence numbers of the above\|mentioned multivalent elements. The element Au often behaves as a liquid phase element and a multivalence\|phile element in the course of deformation and metamorphism, in which the activThe Jinping mountain region on the western margin of the Kang\|Dian axis is situated in the area bordered by the eastern margin of the Qinghai—Xizang Plateau on the west and the western margin of the Yangtze plate on the east, and consists of three\|layer structures: basement (Kang\|Dian axis), detachment zone (sliding surface of lateral extension and thrusting) and the overburden of the Jinping mountain nappe. The intense intracratonic deformation and metamorphism within the Kang\|Dian axis resulted in the activation, migration and enrichment of mineral elements and finally the formation of ore deposits in the Jinping mountain region. As for the Kang\|Dian axis as the crystalline and folded basement, the lower background values ((0 4～0 8)×10 -9 ) of the element Au don’t represent the initial contents, which have mostly been activated and moved away.. In the Lizhuang\|Lawo\|Bazhe zone as the detachment structural zone, the high er background values ((6～10)×10 -9 ) of the element Au don’t represent the initial contents as well, which have received more gold from the multistage ductile shear zones in the detachment zone. As a result of the lower degrees of deformation and metamorphism within the overburden of the Jinping mountain nappe, the lower temperatures and pressures are insufficient to activate and migrate the element Au; the Au contents available represent the initial Au contents ranging between 1 6 and 2×10 -9 , which are equal to the crustal clarke values from Li Tong and Dai Wentian. The activation and migration of the element Au are believed to be governed by the temperatures and transported media especially variable valent elements and their compounds (principally H 2O, Cl, CO 2 , S and Fe). The associated sediments are also correlated with the transported media especially the valence numbers of the above\|mentioned multivalent elements. The element Au often behaves as a liquid phase element and a multivalence\|phile element in the course of deformation and metamorphism, i

关 键 词：DEFLUIDIZATION source bed BASEMENT detachment zone of ext ension and THRUSTING (slide surface) OVERBURDEN 

分 类 号：P5[天文地球—地质学]