论文部分内容阅读
雪如岩体主要由中细粒二长花岗岩、中粗粒斑状二长花岗岩组成,在其与郎山组灰岩接触带附近发育有大量的矽卡岩型铜铁矿床或矿化点.岩石及锆石LA-ICP-MS U-Pb、XRF、ICP-AES等分析显示,雪如岩体富K2O、SiO2、LREE及Rb、Ba、Pb、Th等大离子亲石元素,而Nb、Ta、Sr、Ti等高场强元素含量相对较低,稀土元素配分曲线为明显的右倾曲线,具有中等的负Eu异常,属高钾钙碱性-钾玄岩岩石系列和后碰撞花岗岩类,成岩时代分别为79.25±0.97 Ma和79.72±0.51 Ma,形成于早白垩世末-晚白垩世初班公湖-怒江缝合带闭合后、羌塘地体与拉萨地体的后碰撞阶段.综合认为,雪如岩体岩浆源区为下地壳富含流体的石榴石角闪岩相-斜长角闪岩相的镁铁质岩石,是在后碰撞环境下经部分熔融形成的花岗岩类,对班戈地区铜铁多金属成矿非常有利;矽卡岩型铜铁成矿作用发生于80 Ma左右,该认识为区域找矿指明了方向.
The snow-like rock mass mainly consists of medium and fine-grained granite and medium-coarse-grained granite. A large number of skarn-type copper-iron deposits or mineralization sites are developed near the contact zone with the Langshan Formation limestone. The analysis of rock and zircon LA-ICP-MS U-Pb, XRF and ICP-AES shows that the snow-like rock mass is rich in large ion lithophile elements such as K2O, SiO2, LREE and Rb, The contents of high field elements such as Ta, Sr and Ti are relatively low, and the REE distribution curves are obviously right-angled curves with moderate negative Eu anomalies, belonging to the high-K calc-alkaline-potash rock series and the post-collision granite series. The diagenetic age is 79.25 ± 0.97 Ma and 79.72 ± 0.51 Ma, respectively, formed during the post-collision of the Qiangtang terrane with the Lhasa terrane after the closure of the Gonghu-Nujiang suture zone from the end of Early Cretaceous to the Late Cretaceous The Xueru porphyry magma source area is the fluid-rich garnet amphibolite-amphibolite facies mafic rocks in the lower crust, and is a granite class formed by partial melting in a post-impact environment. Ge iron-copper polymetallic mineralization is very favorable; skarn-type copper-iron mineralization occurred in 80 Ma or so, the understanding of regional prospecting Clear direction.