摘要
大松坡锡矿床是三江特提斯成矿域腾冲-梁河锡-钨多金属矿带内的典型锡矿床之一,与古永岩基有密切的成生联系。本文利用LA-ICP-MS锆石U-Pb定年手段对大松坡锡矿床小龙河含锡黑云母花岗岩和二长花岗岩进行制约,两件黑云母花岗岩样品分析结果分别为70.3±3.2Ma和75.3±4.2Ma,一件二长花岗岩样品结果为71.5±2.1Ma,代表了岩浆结晶年龄。LA-MC-ICP-MSU-Pb方法直接对锡石进行年龄测试在国内外研究报道尚少,本文首次对该矿床云英岩型锡矿石中锡石进行定年尝试,结果为75.5±2.6Ma,与岩体年龄在误差范围内一致。小龙河锡矿床含锡岩体与古永岩基年龄一致,表明该含锡岩体可能是古永岩基的一部分。大松坡锡矿床的成矿年龄与含锡岩体年龄一致,表明二者同时形成,共系新特提斯洋俯冲构造背景的产物。
The Dasongpo tin deposit is located in Tengchong-Lianghe Sn-W metallogenic belt in the Sanjiang Tethys metallogenic domain, which is related to Guyong batholith. In the Dasongpo tin deposit, the Xiaolonghe biotite-granite and monzogranite yielded zircon U-Pb ages of 71.5±2.1Ma～75.3±4.2Ma, and 70.3±3.2Ma respectively, likely represents crystallization age of magma. Few researches have reported on the cassiterite LA-MC-ICP-MS U-Pb dating in China and overseas. In order to constrain the timing of metallogenic age better, we carried out cassiterite U-Pb dating for the greisen-type ore with age of 75.5±2.6Ma. The ages of the Xiaolonghe tin-bearing granitoid are similar with those of the Guyong batholith, indicating the tin-bearing granitoid as a part of the Guyong batholith. Metallogenic age is similar with that of tin-bearing granitoid, indicating their formation at the same time from the subduction of the Neo-Tethys Ocean.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第4期1223-1235,共13页
Acta Petrologica Sinica
基金
国家重点基础研究发展规划项目(2009CB421008)
北京市优秀博士学位论文指导老师科研项目(20111141501)
中央高校基本科研业务费专项资金(2010ZD11)联合资助
