内蒙古金厂沟梁西对面沟岩体岩石地球化学特征及意义

LITHOGEOCHEMISTRY AND SIGNIFICANCE OF THE XIDUIMIANGOU ROCK BODY IN JINCHANGGOULIANG, INNER MONGOLIA

早白垩世西对面沟花岗岩岩体的岩石地球化学研究表明,它具有高锶花岗岩的特征:高铝(Al2O3=14.51%～16.57%,平均为15.434%)、富钠(Na2O=3.75%～4.71%,平均为4.313%)、高锶(Sr=701×10-6～931×10-6,平均为802×10-6),强烈重稀土亏损,无明显的负铕异常或具有正铕异常,过渡元素富集.该岩体很可能与中国东部岩石圈减薄有关,对探讨华北克拉通北缘岩浆起源有重要意义.

Lithogeochemical study shows that the Early Cretaceous Xiduimiangou rock body is typical high-Sr granite, characterized by high Al （14.51% to 16.57% of Al2O3, 15.434% in average）, high Na （3.75% to 4.71% of Na20, 4.313% in average） and high Sr （701×10^-6×10^-6 to 931×10^-6 of Sr, averagely 802×10^-6） contents, with severe HREE deficiency （21.07 - 29.13 of （La/Yb）N, 23.54 in average）, slightly negative or positive Eu anomalies and rich transitional elements. The rock body is likely related to the thinning of lithosphere in Eastern China, It is importantly significant for the research on the origin of magma in the northern margin of North China Craton.