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491.
DISCUSSION ABOUT THE PETROGENESIS OF THE CENOZOIC VOLCANIC ROCKS FROM YUMEN AND HOH XIL AREA, QINGHAI-TIBET PLATEAU 相似文献
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介绍了爆破地震动强度的主要因素及经验公式 ,分析了利用最小二乘法求场地系数K、α值方法的不足之处 ,提出最大似然法求解K、α值的新思路 ,并用实例证明了其具有更高的预测准确度 相似文献
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Plagioclases occur mainly as phenocrysts in volcanic rocks of King George Island, South Shetland Islands, West Antarctica. In basaltic andesites and andesites of Keller Peninsula and Ullman Spur (Admiralty Bay), they are high structure state labradorite-andesines; and in high-A1 basalts and basaltic andesites of Barton and Weaver peninsulas (Maxwell Bay), they are high structure state bytownite-anorthites.∑REE, La/Yb ratios and δEu values of plagioclases from Admiralty Bay are higher than those from Maxwell Bay. All plagioclases have rather identical chondritenormalized transitional element distribution patterns, probably reflecting that crystal structure rather than composition of plagioclase controls their diversity. Compositions of plagioclases depend chiefly on those of their host rocks, compositional differences of plagioclases reveal that basaltic magmas in the Admiralty Bay area are more evolved than in the Maxwell Bay area. 相似文献
499.
与我国相毗邻的蒙古、俄罗斯超大型火山岩型铀矿床的发现促进了我国对额尔古纳—满洲里地区中生代火山岩铀成矿条件的研究。在野外调研、样品分析及资料综合整理基础上,本文从火山岩的火山喷发旋回与演化、岩性组合、岩石铀含量、岩石化学及火山岩形成环境方面分析了该区中生代火山岩的铀成矿地质条件,认为该区与国内外产铀火山岩特征相似,成矿地质条件优越,是我国超大型火山岩型铀矿床极具远景的地区。 相似文献
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The distribution of Oil & gas fields shows their close relationship with the most active tectonic regions. This is not a coincidence but having a scientific reasons. The crustal active regions, refer to the places where the active natural earthquake, volcanic activities, underground water happened, and the areas of the leaking off of natural gas to the surface of the crust. The magma of volcanic activities brings the organic "kitchen range body" hydrocarbon- generating model and inorganic genetic hydrocarbon to the regions covered by volcanic rock. Underground water brings a catalytic hydrocarbongenerating model for organic matter, and the leaking- off of H2 and CO2 contributes a synthetic hydrocarbon - generating model. Volcanic activities bring the assemblage of Source, Reservoir and Seal formed by the sediments and magma the sedimentary basins, and the hydrocarbon - generating system with a "water - volcano" binary structure is formed. All these conditions are favorable and excellent for the formation of oil & gas fields. The distribution of American oil & gas fields have very close relationship with the mines of Fe, Mn, Ct, Mo, W and V, deposits of Zn, Cu, V, Pb, Al and Hg, and the deposits of fluorite, sulfur, potassium salt, phosphate and halite, and the distribution of sulfate- chloride of river water. The reason why few oil & gas fields discovered in the regions covered by volcanic rock in western America maybe because of the view of "inconsistency between petroleum and volcano". Further more, It's very difficult to carry out a geophysical exploration in such kinds of regions.This paper examined a few hydrocarbon-generating models (systems) mentioned above and came up with some fresh ideas on the exploration in the areas covered with volcanic rocks. 相似文献