跃进地区奥陶系硅质岩地球化学特征及成因研究  

Geochemical Characteristics and Origin of the Ordovician Siliceous Rocks in Yuejin Region

作　　者：洪才均[1] 康仁东[1] 韩俊[1] 吴鲜[1] 文山师[1] 房晓璐[1] Hong Caijun;Kang Rendong;Han Jun;Wu Xian;Wen Shanshi;Fang Xiaolu(Exploration ＆ Production Research Institute,SINOPEC Northwest Oilfield Company,Urumqi,Xinjiang,830011,China)

机构地区：[1]中国石化西北油田分公司勘探开发研究院,新疆乌鲁木齐830011

出　　处：《新疆地质》2018年第2期239-245,共7页Xinjiang Geology

基　　金：国家科技重大专项(2016ZX05005-002)资助

摘　　要：跃进地区奥陶系一间房组硅质岩广泛发育。通过对硅质岩岩心观察、岩石学特征、地球化学特征分析,对硅质岩成因机制进行研究。岩心及镜下薄片观察表明,研究区硅质岩为交代作用形成,伴生有金红石、角闪石、萤石等热液矿物。通过对取心岩样地质特征观察及硅质岩样品采样,进行硅质岩主量元素、微量元素及稀土元素分析。硅质岩主量元素分析表明,硅质岩的形成与热液活动有关;微量元素Co/Ni、Th/U、Rb/Sr比值较低,表明热源可能来自下地壳或上地幔;稀土元素分布曲线与塔河英安岩具较强相似性,表明富硅流体可能为与海西晚期火山活动有关的岩浆热液流体。认为跃进地区硅质岩为富含硅质的岩浆热液沿断裂及裂缝进入一间房组碳酸盐岩,与围岩发生水岩反应,碳酸盐岩部分被溶解,同时硅质交代碳酸盐矿物形成残余结构硅质岩。Siliceous rocks are widely distributed in Ordovician Yi Jianfang formation in Yuejin region. Observation of geological characteristics of the samples, Petrological characteristics and analyses of Geochemical characteristics, The genetic mechanism of siliceous rocks has been studied. The observation of core and thin film shows that the siliceous rocks are metasomatic, There are hydrothermal minerals, such as rutile, hornblende and fluorite associated with siliceous rocks. Through the observation of geological features of core samples, Systematic sampling of siliceous rock samples for the analysis of main elements, trace elements and rare earth elements of siliceous rocks. The Major element of Siliceous rock Indicates he formation of siliceous rocks is related to hydrothermal activity. The microelement Co/Ni、Th/U、Rb/Sr are relatively low, it shows that the heat source may come from the lower crust or the upper mantle. Distribution curve of rare earth elements is similar to Ta He dacite, it shows that rich silicon fluid is related to magmatic hydrothermal fluid.Analysis shows that, the Siliceous fluid get into carbonate rocks of Yi Jianfang formation along fracture and crack, carbonate rock is dissolved, and the siliceous metasomatism carbonate minerals.

关 键 词：跃进地区 奥陶系 硅质岩 地化特征 成因研究 

分 类 号：P618.13[天文地球—矿床学]