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通过系统的野外地质调查和岩石化学分析,探讨了藏南彭错林硅质岩的地球化学特征及其沉积环境。研究表明,厚层状绿色、棕褐色硅质岩具有较高的SiO_2含量,局部受Fe,Mn矿化,Al/(Al+Fe+Mn)比值小,在Fe-Mn-Al三角成因判别图解中,大部分硅质岩样品落入热水沉积区域,微量元素Sr,Zr,Cu,Zn和Ba含量较高,稀土元素∑REE较低,Ce负异常,Eu正异常,北美页岩标准化后配分模式稍向左倾,体现出热水沉积特征;在沉积环境判别图中,硅质岩样品投影到洋中脊或深海区域,说明形成于大洋中脊和深海盆地环境;硅质岩的形成与板块的汇聚消减产生的以洋中脊和海底热点为中心的洋壳热水系统有关。
The geochemical characteristics and sedimentary environment of Penglaolin chert in South Tibet are discussed through the systematic field geological survey and petrochemical analysis. The results show that the thick layered green and tan chert are characterized by higher SiO 2 content, locally mineralized by Fe and Mn, and lower Al / (Al + Fe + Mn) ratio. , Most of the samples of silicalite fell into the hot water deposition area, and the contents of trace elements Sr, Zr, Cu, Zn and Ba were higher, the ΣREE of REEs was lower, the anomalies of Ce were negative and the Eu was anomalous. After standardization of North American shales In the sedimentary environment discrimination map, the samples of silicalite are projected to the mid-ocean ridge or the deep-sea area, indicating the environment formed in the mid-ocean ridges and the deep-sea basins. The formation of the chert Subsidence of plate convergence resulting from mid-ocean ridge and ocean floor hot water as the center of the hot water system.