| 摘要: |
| 中上扬子地区广泛发育着完整的奥陶系地层,其中的上奥陶统宝塔组中出现地球化学异常。綦江观音桥剖面中上奥陶统地层的地球化学研究表明,宝塔组中V、Ni出现亏损,V/(V+Ni)值表现为低值,而Th/U、Ni/Co与Sr/Ba值却表现为高值,判断晚奥陶世中宝塔期为强氧化气候,海水突然加深,是一次明显的海侵过程。中上奥陶统地球化学异常是华夏板块与扬子板块相互作用的结果。 |
| 关键词: 中上扬子地区 中上奥陶统 地球化学异常 古环境 |
| DOI： |
| 附件 |
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| 基金项目:中国地质调查局“中上扬子海相含油气盆地分析与油气成藏条件综合调查评价”项目(1212010733505)和“雪峰山西侧海相油气地质调查”项目(1212010782003) |
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| Trace element geochemistry of the Middle and Upper Ordovician strata in the Guanyinqiao section,Qijiang,Chongqing |
| XIE Shang-ke, WANG Zheng-jiang, WANG Jian, ZHUO Jie-wen |
(1. Graduate School, Chinese Academy of Geological Sciences, Beijing 100037, China;
2. Chengdu Institute of Geology and Mineral Resources, Chengdu 610081, Sichuan, China) |
| Abstract: |
| The complete Middle and Upper Ordovician strata are of widespread occurrence in the middle-upper Yangtze area.The geochemical examination of the Middle and Upper Ordovician strata in the Guanyinqiao section,Qijiang,Chongqing have disclosed that the Baota Formation displays V and Ni depletion,low V/(V+Ni) ratios,and high Th/U and Ni/Co ratios.These values imply that there was once one phase of transgression during the deposition of the Baota Formation under the highly oxidized climatic conditions.The geochemical anomalies in the Middle and Upper Ordovician strata may be attributed to the interaction of the Cathaysian plate and Yangtze plate. |
| Key words: middle-upper Yangtze area Middle and Upper Ordovician strata geochemical anomaly palaeoenvironment |
