知识与财富的链接
位于中天山地块南缘大黑山地区的阿拉塔格花岗岩体,岩性主要由花岗闪长岩、二长花岗岩、似斑状花岗岩组成,岩石具有高硅(w（SiO2）为66.29%~77.47%)、富碱(w（Na2O+K2O）为6.75%~9.93%)、高铝(w（Al2O3）为10.97%~14.40%)、低Sr(w（Sr）为（28.78~153.00）×10-6,平均为99.23×10-6)、低Ti（w（TiO2）为0.09％~0.77％）的特征。岩石的A/CNK值为1.19~1.50,为钙碱性过铝质岩石;岩石Eu亏损（δEu＝0.19~0.51）、LREE富集(LREE/HREE= 6.80~8.45,(La/Yb)N= 6.06~9.03),明显富集Rb、Th、K、Hf(Zr) 等大离子亲石元素(LILE),亏损Nb、Ta、P、Ti等高场强元素(HFSE);岩石的Ba含量较低,并具有明显的Sr负异常。结合区域地质特征,通过岩石的地球化学和Sr、Nd同位素综合分析,认为该花岗岩形成于后碰撞环境,且为壳幔混源的岩浆多期次侵位的复合岩体。
The granitoid rocks in Alatage, located in southern margin of central Tianshan plate in Daheishan area, are mainly composed of granodiorite, adamellite and porphyaceous granite. The granites are characterized by high SiO2(66.29%-77.47%), high Na2O+K2O (6.75%-9.93%), high Al2O3 (10.97%-14.40%), and low Sr((28.78-153.00)×10-6, averaging 99.23×10-6) , and low TiO2（0.09%-0.77%). The comprehensive analysis suggests that the granites are peraluminous calc alkalic series rocks(A/CNK=1.19-1.50); REE analysis shows that the averaged ∑REE is 362.04×10-6, the ratios of LREE/HREE and (La/Yb)N are 6.80-8.45,6.06-9.03 respectively. The REE distribution patterns show that the granites are enriched in LREE and depleted in Eu; the trace elements distribution patterns show that the granites are enriched in Rb, Th, K, Hf and Zr（LILE）except Ba, and depleted in Nb, Ta, P and Ti（HFSE）, especially depleted in Sr. Y-Nb, Y+ Nb-Rb and R1-R2 diagrams and Sr, Nd isotopic comprehensive analyses indicate a tectonic setting of post collision. The granites belong to granite complexes with mixed origin and multiple stages of intrusion.