| 燕山地区中元古界高于庄组和杨庄组地球化学特征及环境意义 |
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| 引用本文： | 汪凯明,罗顺社.燕山地区中元古界高于庄组和杨庄组地球化学特征及环境意义[J].矿物岩石地球化学通报,2009,28(4):356-364. |
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| 作者姓名： | 汪凯明 罗顺社 |
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| 作者单位： | 长江大学,油气资源与勘探技术教育部重点实验室,湖北,荆州,434023;长江大学,地球科学学院,湖北,荆州,434023 |
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| 基金项目： | 中国石油化工股份有限公司海相油气勘探前瞻性项目，湖北省高等学校优秀中青年科技创新团队项目 |
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| 摘 要： | 在燕山地区中元古界高于庄组与杨庄组地层野外露头沉积特征研究的基础上,结合区域地质背景,根据26件碳酸盐岩样品的常量元素和微量元素相关关系、组分含量及某些元素的比值对特征,探讨了研究区元素的沉积地球化学特征与古环境意义。研究表明,（1）碳酸盐岩中Sr与CaO呈明显正相关;Al2O3、K2O与TiO2之间呈明显的正相关;SiO2与CaO、MgO呈负相关;Na2O与MgO呈弱正相关;MnO仅与FeO有弱正相关关系。（2）Sr主要赋存于方解石晶格中,Sr和1000×Sr/Ca值随沉积水体的加深而增大,可作为判断古水深的标志。（3）据Sr/Ba、镁铝比值（m=100×MgO/Al2O3）、MgO/CaO值及Ti等元素特征分析,高于庄组与杨庄组的沉积环境有较大差异,高于庄组为潮湿气候下陆源碎屑供应匮乏的远岸陆表海沉积,以高于庄组三段沉积时水体最深;而杨庄组为干热气候下的近岸陆表海沉积,有较多的陆源碎屑物质供应。总之,元素地球化学特征反映的沉积环境与宏观岩性特征所得出的结论是一致的,这表明地球化学特征与沉积环境关系密切,地球化学特征可作为沉积相分析的重要标志。
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| 关 键 词： | 燕山地区 中元古界 碳酸盐岩 高于庄组 杨庄组 地球化学特征 沉积环境 |
Geochemical Characteristics and Environmental Significance of Gaoyuzhuang and Yangzhuang Formations in Yanshan Region |
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| WANG Kai-ming,LUO Shun-she.Geochemical Characteristics and Environmental Significance of Gaoyuzhuang and Yangzhuang Formations in Yanshan Region[J].Bulletin of Mineralogy Petrology and Geochemistry,2009,28(4):356-364. |
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| Authors: | WANG Kai-ming LUO Shun-she |
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| Abstract: | This study discussed the sedimentary geochemistry characteristics and the palaeosedimentary environment significance of Gaoyuzhuang and Yangzhuang Formations, Mesoproterozoic formations in Yanshan Region, on the basis of outcrop observations, regional geological background and the geochemical analyses of 26 rock samples. The results indicated: (1) Sr and CaO in carbonates remarkably positively correlated with each other; Al_2O_3 and K_2O apparently positively correlated with TiO_2; SiO_2 negatively correlated with CaO and MgO; MgO and Na_2O weakly positively correlated with each other; and MnO weakly positively correlated with FeO only. (2) A majority of Sr was found in calcite. The content of Sr and the value of 1000×Sr/Ca increased with the depth of sedimentary water. (3) The analytic results of element Ti and the ratios of Sr/Ba, MgO/Al_2O_3, and CaO/MgO revealed that the palaeosedimentary environments of Gaoyuzhuang Formation and Yangzhuang Formation were significantly different: Gaoyuanzhuang Formation is ocean sediment which was formed far away from the shore in humid climate with little terrigenous clastic materials imputting; especially, the third member of Gaoyuzhuang Formation was formed in the deepest water environment; Yangzhuang Formation is coastal marine sediment which was formed in dry and hot climate with certain terrigenous clastic materials imputting. In summary, the geochemical characteristics and the sedimentary environment are closely correlated, and the geochemical characteristics can be regarded as an important mark in the sedimentary phase analyses. |
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| Keywords: | Yanshan region Mesoproterozoic carbonate Gaoyuzhuang Formation Yangzhuang Formation geochemical characteristics sedimentary environment |
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