CAJ | 학술논문

通过对藏南隆子-古堆一带广泛发育近东西走向的中基性脉岩较系统的地质年代学和岩石地球化学研究，3个基性脉岩的SHRIMP锆石U-Pb年龄为133～140.9Ma，代表了辉长岩的结晶年龄，而中性脉岩的SHRIMP锆石U-Pb年龄130±1.7Ma代表了闪长岩的结晶年龄。表明中基性脉岩属于钙碱性-碱性系列，总体富TiO2，平均含量为3.08，LREE富集，轻重稀土分异较为明显，LILE略为富集，HFSE亏损不明显，属被动大陆边缘构造环境，可能代表了早白垩世新特提斯洋扩张引起喜马拉雅被动大陆边缘一侧裂解的产物。
통과대장남륭자-고퇴일대엄범발육근동서주향적중기성맥암교계통적지질년대학화암석지구화학연구，3개기성맥암적SHRIMP고석U-Pb년령위133～140.9Ma，대표료휘장암적결정년령，이중성맥암적SHRIMP고석U-Pb년령130±1.7Ma대표료섬장암적결정년령。표명중기성맥암속우개감성-감성계렬，총체부TiO2，평균함량위3.08，LREE부집，경중희토분이교위명현，LILE략위부집，HFSE우손불명현，속피동대륙변연구조배경，가능대표료조백성세신특제사양확장인기희마랍아피동대륙변연일측렬해적산물。
Geochronoloical study for intermediate-basic dyke in the Gudui region, south Tibet indicates that SHRIMP U-Pb dating for zircons from three basic samples yields an age of 133-140.9Ma, representing the crystallization age of gabbro, while the SHRIMP U-Pb dating for zircons from the intermediate sample yields an age of 130±1.7Ma, representing the crystallization age of diorite. Petrochemical study indicates that the intermediate-basic rocks are calc-alkaline and alkaline series with high TiO2 of the average content of 3.08%. They are characterized by enrichment in LREE and high ratios of LREE/HREE, and slight enrichment in LILE, and less loss of HFSE. All these prove that the tectonic setting is WPB. The intermediate-basic rocks may be regarded as the products of the splitting of the Himalayan passive margin which caused the large-scale spreading of the Late Neo-Tethys ocean during the Late Jurassic-Early Cretaceous.