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赣南地区寒武纪–震旦纪沉积地球化学特征差异性及其地质意义
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Abstract:
赣南地区是华南东段的重要组成部分，广泛出露的震旦纪和寒武纪地层使其成为研究华南物源分析的理想之地。前人研究多集中于碎屑锆石同位素体系，对不同时代沉积岩地球化学特征差异性研究较少涉及。沉积地球化学特征研究表明赣南地区震旦纪和寒武纪沉积岩具有相似的主量元素组成，微量元素方面都具有亏损Nb、Sr、P和Ti等元素特征，稀土元素配分曲线表现出右倾，强烈的Eu负异常及弱Ce负异常，但寒武纪样品具有更高的La/YbN值，暗示沉积物源区发生了明显的变化。结合前人研究认为，赣南地区震旦纪和寒武纪沉积岩物源主要为长英质物质，晚新元古代到早古生代构造背景为被动大陆边缘。
Gannan area is an important part of the eastern section of South China. The widely exposed Sinian and Cambrian strata make it as an ideal place for provenance analysis of South China. Previous studies mostly focused on the isotopic analysis of detrital zircons, and seldom involved on the differences in geological characteristics of sedimentary rocks. In this paper, geochemical characteristics have shown that the Sinian and Cambrian sedimentary rocks in south Jiangxi Province have similar major element compositions, and trace elements which all depleted in Nb, Sr, P and Ti. The rare earth elements show strong Eu anomalies and weak Ce anomalies, but the Cambrian sedimentary rocks have the higher La/YbN values, suggesting that sediment source area has changed significantly. Based on previous studies, it is believed that the source of Sinian and Cambrian sedimentary rocks in southern Jiangxi is mainly felsic material, and the tectonic setting from Late Neoproterozoic to Early Paleozoic is a passive continental margin.
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