鲁东文登地区文登型（超单元）花岗岩体的SHRIMP锆石年代学

SHRIMP Zircon Geochronology of Wendeng Type Granites in Wendeng City in Ludong Area

摘要:

文登岩体主要岩性为不同粒度的二长花岗岩，原划为三叠纪。根据新测的锆石SHRIMP UPb年龄为(167±3) Ma,(167±2) Ma,(157.1±1.4) Ma，结合野外接触关系改划为侏罗纪。文登花岗岩体属侏罗纪钙碱系列的侵入体，主要显示长英质陆壳深熔花岗岩的特征。推断其形成于中下地壳深度,可能来源于加厚陆壳的部分熔融，是加厚下地壳的拆沉作用的产物, 而且可能标志着中国东部岩石圈减薄的开始。

Abstract:

Rock lithology of Wendeng rock bodies are monzogranite with different sizes. It was classified into the Triassic originally. According to newly measured zircon SHRIMP U-Pb age of (167±3) Ma, (167±2) Ma and (157.1±1.4) Ma, combining with field contact relationship, it is classified into the Jurassic. Wendeng granite bodies are Jurassic calc-alkaline series intrusive bodies, and mainly showed the characteristics of felsic continental crust anatectic granite. It is concluded that it was formed in the middle and lower crustal depth, and may be derived from partial melting of thickened continental crust. It is the product of delamination of thickened lower crust, and may mark the beginning of lithospheric thinning.