摘要
Abstract
The Nuomin area in Daxinganling is tectonically located in the east section of the Xingan-Mongolian orogenic belt, where large volumes of Permian granitic rocks, mainly monzogranite and moyite, are developed. Major element analysis shows high SiO2 and alkali content, slightly high K2O content and low MgO and CaO contents. Trace element study demonstrates the enrichment of Rb, Th, K, Nd and Cs, and depletion of Ba, U, Nb, Sr, P and Ti. The samples are enriched in LREE and depleted in HREE, with apparent negative Eu anomalies, suggesting a high degree of fractionation. The granites generally belong to the high-K calc-alkaline series. Petrogeochemistry shows that the granites are quite similar to S-type granite. They are most likely resulted from the partial melting of homologous crust, probably derived from metamorphic greywacke and intermediate volcanic rocks. According to the discrimination diagrams of R1-R2, Rb-(Yb+ Nb) and Rb-( Yb+Ta), the granites are generated in the stage of post-collision after the collision between Xingan block and Songnen block.关键词
诺敏地区/花岗岩/地球化学/地壳源区/大兴安岭Key words
Nuomin area/ granite/ geochemistry/ crust source/ Daxinganling分类
天文与地球科学
