地质与勘探2017，Vol.53Issue(5)：825-837,13.
东昆仑石头坑德镁铁-超镁铁质岩体矿物学特征及成矿指示
Mineralogical Characteristics of the Shitoukengde Mafic-Ultramafic Intrusions in East Kunlun Orogenic Belt and the Ore-Forming Indication
摘要
Abstract
The Shitoukengde mafic-ultramafic intrusions, adjacent to the middle-Kunlun fault, lie in the Wulonggou area in the eastern section of the East Kunlun orogenic belt. It is composed of pyroxenite, olivine pyroxenite, peridotite and gabbro. The Ni-Cu orebodies mainly occur in the pyroxe-nite, olivine pyroxenite and peridotite of the No. I intrusion. Petrogeochemical characteristics of rocks show that the m/f values of these rocks range from 2. 77 to 6. 01, and the ore-bearing rocks belong to ferruginous series mafic-ultramafic intrusions that are favorable for the formation of magmatic Ni-Cu sulfide ore bodies. These rocks have low total rare earth element values, showing obvious fractionation between LREE and HREE, with intense LREE fractionation but weak HREE fractionation. They are enriched in LILE ( Rb, Ba, Th and U) while depleted in HFSE ( Nb, Ta, Zr and Y) , and generally show obvious positive Rb and U anomalies, as well as negative Nb and Ta anomalies. The olivines of ultramafic rocks are depleted in Ni content, revealing the immiscibility of the sulfides occurred at depth. It is very favorable for formation of sulfide-enriched magma, with massive Ni entering the sulfides be-fore olivine crystallization. During the upwelling process of mantle-derived magma, the S was supersaturated in the magma due to the addition of crustal materials accompanied with the occurrence of assimilation and contamination, followed by the immiscibility of the sulfides. Analysis suggests that the sul-fide-enriched magma migrated to the weak structural portation of the middle-Kunlun fault nearby the East Kunlun orogenic belt to form mineral depos-its. Magmatic Ni-Cu sulfide ore bodies are mostly hosted in the ultramafic rocks containing plenty of olivines, suggesting that the deep part of the Shi-toukengde intrusions is the locality with highly enriched Ni-Cu sulfide bodies, thus the target of further ore prospecting.关键词
矿物学特征/镁铁-超镁铁质岩/岩浆铜镍矿床/成矿指示/石头坑德/东昆仑Key words
mineralogical characteristics/mafic-ultramafic intrusions/magmatic Ni-Cu sulfide deposit/ore-forming indicator/Shitoukengde/East Kunlun分类
天文与地球科学引用本文复制引用
张照伟,王亚磊,钱兵,刘月高,祁昌炜,董俊,尹建华..东昆仑石头坑德镁铁-超镁铁质岩体矿物学特征及成矿指示[J].地质与勘探,2017,53(5):825-837,13.基金项目
国土资源部公益性行业科研专项"拉陵灶火镍成矿赋矿机理及勘查技术研究示范"(201511020)和中国地质调查局"东昆仑铜镍多金属资源基地调查"二级项目(DD20160013)共同资助. （201511020）
