塔里木盆地西南缘片麻状花岗岩锆石SHRIMPU-Pb定年  

Zircon SHRIMP U-Pb Dataing of the Gneiss Granite on the Southwestern Margin of the Tarim Basin

作　　者：肖爱芳[1] 黎敦朋[1] 

机构地区：[1]福州大学紫金矿业学院,福建福州350108

出　　处：《西北地质》2010年第4期87-94,共8页Northwestern Geology

基　　金：中国地质调查局<新疆1:25万恰哈幅(J44C004002)区域地质调查>(200313000003)资助

摘　　要：在塔里木盆地西南缘发现多个片麻状英云闪长岩,岩体表现为高S i、A l、N a,富集轻稀土元素、大离子亲石元素和高场强元素的Z r、H f、T i,亏损重稀土元素和高场强元素P、N i、C r,地球化学具有A型花岗岩的特征。通过锆石SHR IM P U-Pb测年,获得3组年龄:第一组年龄,T=(1 970±47)M a(n=4,M SW D=2.4),代表岩浆捕获的继承锆石年龄;第二组年龄,T=(764±33)M a(n=4,M SW D=2.50),代表岩浆结晶年龄;第三组年龄,T=(424±16)M a(n=6,M SW D=1.03),代表加里东期构造事件年龄。T=(764±33)M a的锆石年龄可能是塔里木地块在新元古代末期R od in ia超大陆裂解岩浆活动的记录,对约束该区地层时代、研究地质构造演化提供了重要信息。Discovered several gneiss tonalite bodies on the southwestern margin of the Tarim basin have been reported in the paper.They are possessed of higher Si,Al,Na;enriched in LREE,LILE and Zr,Hf,Ti of HFSE,depleted HREE and P,Ni,Cr of HFSE,and possessed of A-type granite features in geochemistry.Zircon SHRIMP U-Pb dataing showed that there are three group age： the first group age is（1970±47）Ma（n=4,MSWD=2.4） which recorded succeeding zircon age of magma seizured;the second group age is（764±33）Ma（n=4,MSWD = 2.50） which represented intruding age of gneiss granite;the third group age is（424±16）Ma（n=6,MSWD= 1.03） which implied age of Caledonnian tectonic event.It maybe provided a record of magma function brokenup Paleo-continent of Neo-Proterozoic in the Tarim Basin,it provides an important basis for the stratigraphic division in this district and an important information of the geological tectonic evolution.

关 键 词：新元古代 片麻状花岗岩 RODINIA超大陆裂解 塔里木西南缘 

分 类 号：P632[天文地球—地质矿产勘探]