广西栗木锡铌钽矿田矿化花岗岩锆石SHRIMPU—Pb定年及其意义

栗木矿田是南岭地区典型的锡铌钽多金属矿田，成矿作用与花岗岩关系十分密切。本文通过锆石SHRIMPU—Pb法定年研究，获得栗木矿田水溪庙矿区的隐伏矿化花岗岩形成年龄为212．34±1．8Ma（98％可信度，MSWD=1．5），与前人测得的老虎头矿区的云英岩化花岗岩中白云母的Ar-Ar坪年龄（214．1Ma）、金竹源花岗岩中蚀变白云母Ar-Ar坪年龄（212．4Ma）及金竹源和三个黄牛花岗岩体锆石SHRIMPU—Pb年龄（分别为214．0Ma和218-3Ma）在误差范围内一致。结合其它资料分析，我们认为栗木地区锡铌钽矿与花岗岩为印支期同-构造-岩浆活动的产物，建议在南岭地区下一步规划部署中应注意印支期成矿岩体和印支期锡多金属矿的寻找。

SHRIMP U-Pb zircon dating and itssignificance of mineralized granite in Limu Sn-Nb-Ta ore-field,Guangxi, South China.

Sn-Nb-Ta mineralization in Limu, a tipical huge ore field in Nanling Range, has close relation to granitic diagenesis. Zircon SHRIMP U-Pb dating of mineralized granite in concealed Shuiximiao stock was eom- ducted in this paper, yielding an age of 212.3± 1.8 Ma（98% confidence, MSWD=1.5 ）. The result is well consis- tent with those ages from greisenized granite in laohutou district （214.1 Ma）, muscovitilized granite in Jinzhuyuan （212.4 Ma, 214.0 Ma） and sangehuangniu granite （218.3 Ma） in error range. Compiled with other references,it＇s clear that both Sn-polymetallic deposit and granitic stocks in Limu ore-field are production of Indosinian diage- netic and metallogentic activities in this region. As known by geologists in Nanling range, fruitful exploration chievements have been harvested in the vicility of contacts of Indosinian granites, so more attention must be paid on the exploration and evaluation in this region in next few years.