中国地质
中國地質
중국지질
Geology in China
2015年
5期
1324-1336
,共13页
王勤%唐菊兴%方向%林彬%宋扬%王艺云%杨欢欢%杨超%李彦波%卫鲁杰%冯军%李力
王勤%唐菊興%方嚮%林彬%宋颺%王藝雲%楊歡歡%楊超%李彥波%衛魯傑%馮軍%李力
왕근%당국흥%방향%림빈%송양%왕예운%양환환%양초%리언파%위로걸%풍군%리력
多龙矿集区%安山岩%锆石U-Pb定年%岩石地球化学%浅成低温热液%西藏
多龍礦集區%安山巖%鋯石U-Pb定年%巖石地毬化學%淺成低溫熱液%西藏
다룡광집구%안산암%고석U-Pb정년%암석지구화학%천성저온열액%서장
Duolong ore concentration area%andesites%zircon U-Pb dating%petrogeochemistry%epithermal deposit%Tibet
本文主要对出露与西藏多龙矿集区铁格隆南矿区荣那矿段的安山岩开展了锆石U?Pb定年、岩石地球化学测试，旨在确定该套火山岩的成岩年龄及其形成的构造背景。安山岩的LA?ICP?MS锆石U?Pb加权平均年龄为(110.1±0.7) Ma (MSWD=2.3)，代表了其成岩年龄。岩石SiO2为59.5%~61.48%；Al2O3为16.14%~17.11%；Na2O+K2O为6.02%~6.63%；Mg#值中等，微量元素富集Ba、Rb、Th、K等大离子亲石元素，相对亏损Ta、Nb、P、Ti等高场强元素，具有Rb正异常和明显的Zr、Hf负异常，据此认为该安山岩属高钾钙碱性系列岩石，具有活动大陆边缘火山岩的性质，是班公湖—怒江洋北向俯冲，拉萨地体与羌塘地体碰撞拼贴过程中所诱发的岩浆产物。结合其他资料分析认为，此安山岩的成岩时间应晚于铁格隆南高硫型浅成低温热液铜(金)矿床的成岩和成矿时间，是该矿床得以良好保存的重要条件。
本文主要對齣露與西藏多龍礦集區鐵格隆南礦區榮那礦段的安山巖開展瞭鋯石U?Pb定年、巖石地毬化學測試，旨在確定該套火山巖的成巖年齡及其形成的構造揹景。安山巖的LA?ICP?MS鋯石U?Pb加權平均年齡為(110.1±0.7) Ma (MSWD=2.3)，代錶瞭其成巖年齡。巖石SiO2為59.5%~61.48%；Al2O3為16.14%~17.11%；Na2O+K2O為6.02%~6.63%；Mg#值中等，微量元素富集Ba、Rb、Th、K等大離子親石元素，相對虧損Ta、Nb、P、Ti等高場彊元素，具有Rb正異常和明顯的Zr、Hf負異常，據此認為該安山巖屬高鉀鈣堿性繫列巖石，具有活動大陸邊緣火山巖的性質，是班公湖—怒江洋北嚮俯遲，拉薩地體與羌塘地體踫撞拼貼過程中所誘髮的巖漿產物。結閤其他資料分析認為，此安山巖的成巖時間應晚于鐵格隆南高硫型淺成低溫熱液銅(金)礦床的成巖和成礦時間，是該礦床得以良好保存的重要條件。
본문주요대출로여서장다룡광집구철격륭남광구영나광단적안산암개전료고석U?Pb정년、암석지구화학측시，지재학정해투화산암적성암년령급기형성적구조배경。안산암적LA?ICP?MS고석U?Pb가권평균년령위(110.1±0.7) Ma (MSWD=2.3)，대표료기성암년령。암석SiO2위59.5%~61.48%；Al2O3위16.14%~17.11%；Na2O+K2O위6.02%~6.63%；Mg#치중등，미량원소부집Ba、Rb、Th、K등대리자친석원소，상대우손Ta、Nb、P、Ti등고장강원소，구유Rb정이상화명현적Zr、Hf부이상，거차인위해안산암속고갑개감성계렬암석，구유활동대륙변연화산암적성질，시반공호—노강양북향부충，랍살지체여강당지체팽당병첩과정중소유발적암장산물。결합기타자료분석인위，차안산암적성암시간응만우철격륭남고류형천성저온열액동(금)광상적성암화성광시간，시해광상득이량호보존적중요조건。
In this paper, the authors studied the andsites in Rongna ore block, Tiegelong Cu (Au-Ag) deposit, Duolong ore concentration area, Tibet, and used the zircon U-Pb data and petrogeochemistry of andsites to identify the petrogenetic age and tectonic setting of the andsites. The weighted average age of zircon U-Pb is 110.1 ± 0.7 Ma (MSWD=2.3) , which represents the petrogenesis age. An analysis of the whole rock sample shows that SiO2 values are 59.5%-61.48%, Al2O3 values are 16.14%-17.11%and Na2O+K2O values are 6.02%-6.63%;Mg# is of intermediate value. LILE such as Ba, Rb, Th, K are rich, HFSE such as Ta, Nb, P, Ti are relatively poor and characterized by Rb positive anomaly and obvious Zr, Hf negative anomalies. Petrological and geochemical studies show that the andesites are high potassium calc-alkaline rocks exhibiting the characteristics of Andean-type active continental margin volcanic rocks. They resulted probably from partial melting of subducted oceanic slab as well as miscibility with crustal material during the upward migration of the magma in the case that subducted oceanic slab didn’t interact with the mantle. They were the magma products of the northward subduction of Bangong Co-Nujiang Ocean and Lhasa and the collision collage process of Qiangtang terrane. In combination with other dating data and drilling core catalog data, the authors hold that the formation of andesites was later than the rock-forming and ore-forming stage of the Tiegelongnan high sulfur epithermal Cu (Au-Ag) deposits, which seems to have been the important condition for the preservation of the ore deposit.
