| 琼东南盆地陵南低凸起深水钻井岩心的稀土元素地球化学特征及其意义 |
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| 引用本文： | 孙志鹏,翟世奎,修淳,刘新宇,宗统,罗威,刘晓锋,陈奎,李娜.琼东南盆地陵南低凸起深水钻井岩心的稀土元素地球化学特征及其意义[J].海洋学报(英文版),2014,33(12):81-95. |
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| 作者姓名： | 孙志鹏 翟世奎 修淳 刘新宇 宗统 罗威 刘晓锋 陈奎 李娜 |
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| 作者单位： | 中海石油(中国)有限公司, 湛江分公司研究院, 广东 湛江 524057;中国海洋大学:海底科学与探测技术教育部重点实验室, 海洋地球科学学院, 山东 青岛 266100;中国海洋大学:海底科学与探测技术教育部重点实验室, 海洋地球科学学院, 山东 青岛 266100;中海石油(中国)有限公司, 湛江分公司研究院, 广东 湛江 524057;中国海洋大学:海底科学与探测技术教育部重点实验室, 海洋地球科学学院, 山东 青岛 266100;中海石油(中国)有限公司, 湛江分公司研究院, 广东 湛江 524057;中国海洋大学:海底科学与探测技术教育部重点实验室, 海洋地球科学学院, 山东 青岛 266100;中国海洋大学:海底科学与探测技术教育部重点实验室, 海洋地球科学学院, 山东 青岛 266100;中国海洋大学:海底科学与探测技术教育部重点实验室, 海洋地球科学学院, 山东 青岛 266100 |
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| 基金项目： | The National Major Project of Science and Technology of China under contract No. 2011ZX05025-002-03. |
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| 摘 要： | A geochemical analysis of rare-earth elements(REEs) in 97 samples collected from the core of deep-water Well LS-A located at the Lingnan Low Uplift Area of the Qiongdongnan Basin is conducted, with the purpose of revealing the changes of sedimentary source and environment in the study region since Oligocene and evaluating the response of geochemical characteristics of REEs to the tectonic evolution. In the core samples, both ∑REE and ∑LREE(LREE is short for light-group REEs) fluctuate in a relatively wide range, while ∑HREE(HREE is short for heavy-group REEs) maintains a relatively stable level. With the stratigraphic chronology becoming newer, both ∑REE and ∑LREE show a gradually rising trend overall. The ∑REE of the core is relatively high from the bottom of Yacheng Formation(at a well depth of 4 207 m) to the top of Ledong Formation, and the REEs show partitioning characteristics of the enrichment of LREE, the stable content of HREE, and the negative anomaly of Eu to varying degrees. Overall the geochemical characteristics of REEs are relatively approximate to those of China's neritic sediments and loess, with significant "continental orientation". The ∑REE of the core is relatively low in the lower part of Yacheng Formation(at a well depth of 4 207–4 330 m), as shown by the REEs partitioning characteristics of the depletion of LREE, the relative enrichment of HREE, and the positive anomaly of Eu; the geochemical characteristics of REEs are approximate to those of oceanic crust and basalt overall, indicating that the provenance is primarily composed of volcanic eruption matters. As shown by the analyses based on sequence stratigraphy and mineralogy, the provenance in study region in the early Oligocene mainly resulted from the volcanic materials of the peripheral uplift areas; the continental margin materials from the north contributed only insignificantly; the provenance developed to a certain extent in the late Oligocene. Since the Miocene, the provenance has ceaselessly expanded from proximal to distal realm, embodying a characteristic of multi-source sedimentation. In the core strata with 31.5, 28.4, 25.5, 23, and 16 Ma from today, the geochemical parameters of REEs and Th/Sc ratio have significant saltation, embodying the tectonic movement events in the evolution of the Qiongdongnan Basin. In the tectonic evolution history of the South China Sea, the South China Sea Movement(34–25 Ma BP, early expansion of the South China Sea), Baiyun Movement(23 Ma BP), late expansion movement(23.5–16.5 Ma BP), expansion-settlement transition, and other important events are all clearly recorded by the geochemical characteristics of REEs in the core.
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| 关 键 词： | 稀土元素地球化学特征 琼东南盆地 隆起区 深水井 岭南 轻稀土元素 地球化学分析 浅海沉积物 |
| 收稿时间： | 2014/6/20 0:00:00 |
| 修稿时间： | 2014/9/29 0:00:00 |
Geochemical characteristics and their significances of rare-earth elements in deep-water well core at the Lingnan Low Uplift Area of the Qiongdongnan Basin |
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| SUN Zhipeng,ZHAI Shikui,XIU Chun,LIU Xinyu,ZONG Tong,LUO Wei,LIU Xiaofeng,CHEN Kui and LI Na.Geochemical characteristics and their significances of rare-earth elements in deep-water well core at the Lingnan Low Uplift Area of the Qiongdongnan Basin[J].Acta Oceanologica Sinica,2014,33(12):81-95. |
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| Authors: | SUN Zhipeng ZHAI Shikui XIU Chun LIU Xinyu ZONG Tong LUO Wei LIU Xiaofeng CHEN Kui and LI Na |
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| Institution: | 1.Zhanjiang Branch of China National Offshore Oil Corporation (CNOOC) Limited, Zhanjiang 524057, China2.Key Laboratory of Submarine Geosciences and Technology of Ministry of Education, Ocean University of China, Qingdao 266100, China |
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| Abstract: | A geochemical analysis of rare-earth elements (REEs) in 97 samples collected from the core of deep-water Well LS-A located at the Lingnan Low Uplift Area of the Qiongdongnan Basin is conducted, with the purpose of revealing the changes of sedimentary source and environment in the study region since Oligocene and evaluating the response of geochemical characteristics of REEs to the tectonic evolution. In the core samples, both ΣREE and ΣLREE (LREE is short for light-group REEs) fluctuate in a relatively wide range, while ΣHREE (HREE is short for heavy-group REEs) maintains a relatively stable level. With the stratigraphic chronology becoming newer, both ΣREE and ΣLREE show a gradually rising trend overall. The ΣREE of the core is relatively high from the bottom of Yacheng Formation (at a well depth of 4 207 m) to the top of Ledong Formation, and the REEs show partitioning characteristics of the enrichment of LREE, the stable content of HREE, and the negative anomaly of Eu to varying degrees. Overall the geochemical characteristics of REEs are relatively approximate to those of China's neritic sediments and loess, with significant “continental orientation”. The ΣREE of the core is relatively low in the lower part of Yacheng Formation (at a well depth of 4 207-4 330 m), as shown by the REEs partitioning characteristics of the depletion of LREE, the relative enrichment of HREE, and the positive anomaly of Eu; the geochemical characteristics of REEs are approximate to those of oceanic crust and basalt overall, indicating that the provenance is primarily composed of volcanic eruption matters. As shown by the analyses based on sequence stratigraphy and mineralogy, the provenance in study region in the early Oligocene mainly resulted from the volcanic materials of the peripheral uplift areas; the continental margin materials from the north contributed only insignificantly; the provenance developed to a certain extent in the late Oligocene. Since the Miocene, the provenance has ceaselessly expanded from proximal to distal realm, embodying a characteristic of multi-source sedimentation. In the core strata with 31.5, 28.4, 25.5, 23, and 16 Ma from today, the geochemical parameters of REEs and Th/Sc ratio have significant saltation, embodying the tectonic movement events in the evolution of the Qiongdongnan Basin. In the tectonic evolution history of the South China Sea, the South China Sea Movement (34-25 Ma BP, early expansion of the South China Sea), Baiyun Movement (23 Ma BP), late expansion movement (23.5-16.5 Ma BP), expansion-settlement transition, and other important events are all clearly recorded by the geochemical characteristics of REEs in the core. |
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| Keywords: | Qiongdongnan Basin deep-water well core rare-earth elements sedimentary source and environment response to tectonic movement |
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