| 江陵凹陷古新世盐湖沉积碳酸盐碳氧同位素组成及其环境意义 |
| |
| 关键词:Jiangling depression Palaeocene lacustrine carbonate rock stable isotope palaeoclimate palaeoenvironment |
| 基金项目:国家“973”计划项目(编号: 2011CB403000);中国地质调查局计划项目(编号: 1212010011808);国家自然科学基金青年基金(编号: 41202059) |
|
| 摘要点击次数: 5132 |
| 全文下载次数: 1818 |
| 摘要: |
| Carbon and Oxygen Isotopes Characteristics of Palaeocene Saline Lake Facies Carbonates in Jiangling Depression and Their Environmental Significance |
| The Jiangling depression is located in the west of Jianghan rift basin, and potassium-rich brine was mainly formed in Palaeocene. The study of the palaeoclimate evolution in Palaeocene has great theoretical and practical significance for further potash survey. The δ13CPDB values of carbonate in Shashi Formation of Jiangling depression vary between –4.8‰ and –1.0‰ with an average of –3.4‰; the δ18OPDB values are between –5.6‰ and –0.6‰ with an average of –3.3‰; the δ13CPDB values of carbonate in Xingouzui Formation of Jiangling depression are in the range of –10.8‰ ~ –8.8‰ with an average of –9.3‰; the δ18OPDB values are between –10.2‰ and –6.7‰ with an average of –8.6‰. The δ13CPDB and δ18OPDB values of micrite in Shashi Formation show good positive correlation, suggesting a relative closed salt lake system with apparent evaporation. However, in Xingouzui Formation, the relationship between δ13CPDB and δ18OPDB is indistinct, implying an open lake system whose water was stagnant only for a short time. The carbon and oxygen isotopes as well as Sr/Ba and Mg/Ca ratios reveal that Shashi Formation had relatively high paleosalinity and evaporation/raining ratio. The paleo-lake surface is higher in Xingouzui Formation than in Shashi Formation. The differences of carbon and oxygen isotope compositions of the Palaeocene lake in Jiangling depression reveal the change from dry-hot climate in Shashi Formation to wet climate in Xingouzui Formation. It is thus inferred that the palaeoclimate changed greatly from Shashi Formation to Xingouzui Formation in Jiangling depression throughout the Paleogene period. This change was favorable for the salt lake evolution and potassium deposition in Shashi Formation. |
| WANG Chun-lian,LIU Cheng-lin,XU Hai-ming,WANG Li-cheng,ZHANG Lin-bing.2013.Carbon and Oxygen Isotopes Characteristics of Palaeocene Saline Lake Facies Carbonates in Jiangling Depression and Their Environmental Significance[J].Acta Geoscientica Sinica,34(5):567-576. |
| 查看全文 查看/发表评论 下载PDF阅读器 |