摘要
通过研究南秦岭地区陡岭群、武当群和北秦岭地区秦岭群的变质基性岩等的铅同位素和微量元素组成，揭示出东秦岭造山带分布有两种性质及不同归属的元古宙地壳，指出中、古元古代时可能不存在一个统一的地壳基底；南秦岭的中、古元古代地壳是在扬子陆块基底上通过岛弧的侧向加积形成的，北秦岭元古宙地壳则可能垂向增生于一个富放射性成因铅同位素组成的、具古洋壳幔性质的微地块之上．研究还表明陡岭群不是北秦岭地区的秦岭群。
Two kinds of Proterozoic crustal basements are recognized in the study of Pb-isotope ratios and trace elements of the mafic rocks from Douling Group,Wudang Group of South Qinling area and Qinling Group of North Qinling area in East Qinling orogenic belt.The Proterozoic crustal basements of North and South Qinling might,respectively,belong to different continental blocks.It seems that an integrated crustal basement in Proterozoic did not exist in East Qinling area.The crust of South Qinling was originated from the arc above the northern continental margin of Yangtze craton by side-accretion in Meso-Paleoproterozoic.However,Proterozoic crust of North Qinling might have been formed by vertical accretion above North Qinling block which might consist of paleo-oceanic crust and mantle with high radiogenic Pb-isotope composition.The geochemical data indicate that Douling Groupin South Qinling area is different from Qinling Group of North Qinling area,and so the former should be a part of Proterozoic crustal basement of South Qinling.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
1996年第5期470-480,共11页
Earth Science-Journal of China University of Geosciences
基金
地矿部壳幔体系组成
物质交换及动力学开放研究实验室基金
国家自然科学基金
