| 摘要: |
| 通过对羌塘盆地那底岗日地区上侏罗统—下白垩统索瓦组碳酸盐岩稀土元素丰度、分布模式及稀土总量(ΣREE)的分析,结合总有机碳(TOC)含量、EFMn、Sr/Cu的变化特征,探讨了稀土元素纵向变化与气候环境之间的关系。结果表明:那底岗日地区碳酸盐岩中稀土元素总丰度值平均为45.3μg/g (不包括Y)。稀土元素与总有机碳(TOC)之间存在较好的相关性,与EFMn和Sr/Cu值的变化呈反向对应关系。ΣREE的高值段代表相对湿润的气候环境,ΣREE的低值段代表干热的气候环境。根据稀土元素分布与沉积环境的关系,推断晚侏罗世—早白垩世那底岗日地区经历了干热和相对温湿频繁交替变更的气候演化过程。 |
| 关键词: 羌塘盆地 那底岗日地区 碳酸盐岩 稀土元素 古气候 |
| DOI： |
| 附件 |
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| 基金项目:青藏高原油气资源战略选区调查与评价项目(编号:XQ-2004-06) |
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| REE geochemistry of the Upper Jurassic-Lower Cretaceous carbonate rocks and palaeoclimates in the Nadigangri region,Qiangtang Basin |
| ZHU Li-xia, FU Xiu-gen, TAN Fu-wen, FENG Xing-lei |
(1. Chinese Academy of Geological Sciences, Beijing 100037, China;
2. Chengdu Institute of Geology and Mineral Resources, Chengdu 610081, Sichuan, China) |
| Abstract: |
| The relationship between the vertical variations in REE and palaeoclimates in the Nadigangri region,Qiangtang Basin is based on the REE abundances and distribution patterns,and vertical distribution of REE amounts(ΣREE) in integration with total organic carbon(TOC) contents,EFMn and Sr/Cu ratios for the carbonate rocks from the Upper Jurassic to the Lower Cretaceous Suowa Formation in the Nadigangri region,Qiangtang Basin.The REE contents range between 8.32 and 81.3μg/g,with an average of 45.3 μg/g(not including Y).LREEs are relatively enriched,and display a slightly right-leaning pattern.There is a good correlation between REE and total organic carbon contents,and a negative correlation between REE and EFMn and Sr/Cu ratios.The higher values of ΣREE represent relatively humid climatic conditions,while the lower values of ΣREE represent xerothermic climatic conditions.It is inferred from the REE distribution and sedimentary environments that the Nadigangri region,Qiangtang Basin once went through the alternating changes of xerothermic and warm humid climatic conditions during the Late Jurassic to the Early Cretaceous. |
| Key words: Qiangtang Basin Nadigangri region carbonate rock REE palaeoclimate |
