| 思茅盆地MK-3井上盐段成盐期前后微量元素地球化学特征及其古环境指示意义 |
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| 关键词:Simao Basin clasolite trace elements geochemical paleoenvironment |
| 基金项目:中国地质调查局地质大调查项目“思茅盆地中生代海相钾盐资源调查评价”(编号: DD20201115) |
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| Geochemical Characteristics of Trace Elements before and after the Upper Salt Forming Period of the MK-3 Core, Simao Basin and Their Paleoenvironmental Implications |
| We discuss the paleoenvironment changes before and after the Mesozoic salt forming period in the Simao Basin by comparing the geochemical characteristics of trace elements in clasolite along the upper salt section of the MK-3 core. The average contents of major trace elements, except Mn, were higher before the salt forming period than after it, indicating that the enrichment of trace elements is beneficial for the formation of salt deposits. The chondrite normalized relative content of rare earth elements show a pattern of light rare earth element enrichment with an incline to the right, suggesting that the main material source is terrigenous. δCe values of all 29 samples in MK-3 are greater than 0.9, with an average value of 1.0. Considering the brownish red core lithology, this possibly indicates a weak oxidative sedimentary environment. On the basis of the ratios of Rb/K and Sr/Cu, we believe that before the salt forming period, a brackish water environment with hot climate and high evaporation existed, which provided necessary conditions for salt and potash deposition. After the salt forming period, fresh and saline water conditions alternated, characterized by three warm and humid stages and three extreme hot and drought stages. The continuous freshwater supply resulted in well-developed clasolite after the upper salt layer in the basin. |
| SONG Gao,MIAO Zhong-ying,DU Shao-rong,LI Xin-min.2022.Geochemical Characteristics of Trace Elements before and after the Upper Salt Forming Period of the MK-3 Core, Simao Basin and Their Paleoenvironmental Implications[J].Acta Geoscientica Sinica,43(4):584-592. |
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