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根据三江地区中南部三叠系地层 30 0余件岩石样品分析结果 ,我们对该地区三叠系地层地球化学特征进行了研究。研究表明三江地区中南部三叠系地层明显富集As,Sb和 Ca元素 ,亏损碱金属元素 K,Na,L IL元素 Ba,Th以及相容元素 Co,Cr,Mn,Ni,V ,且轻重稀土元素分异程度较高。在成矿元素方面 ,研究区三叠系地层富集 Pb,Sb,且Cu,Au,Zn的丰度值明显高于华北地台表壳 (出露地壳 )。根据微量元素比值推断 ,三江地区中南部三叠系地层的物源区在地球化学成分方面较典型岛弧造山带上地壳更为成熟
Based on the analysis of more than 30 rock samples from the Triassic strata in the central and southern Sanjiang region, we have studied the geochemical characteristics of the Triassic strata in the area. The results show that the Triassic strata in the central and southern parts of Sanjiang area are obviously enriched in As, Sb and Ca, depleted in Ba, Th and K, Na, and L elements of alkali metals K, Na and L IL, Rare-earth elemental degree of differentiation is higher. In terms of metallogenic elements, the Triassic strata in the study area are enriched in Pb and Sb, and the abundance values of Cu, Au and Zn are significantly higher than those of the North China platform (exposed crust). According to the trace element ratio, the source areas of the Triassic strata in central-southern Sanjiang area are more mature in geochemical composition than the crust on the typical island arc orogenic belt