| 祁连山新生代古海拔变化的碳氧同位素记录 |
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| 引用本文：戚帮申,胡道功,杨肖肖,张绪教,赵希涛.2015.祁连山新生代古海拔变化的碳氧同位素记录[J].地球学报,36(3):323-332. |
| DOI：10.3975/cagsb.2015.03.07 |
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| 基金项目:中国地质调查局天然气水合物资源勘查与试采工程国家专项“祁连山冻土区天然气水合物资源勘查(力学所)”(编号: GZHL20120301) |
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| 中文摘要:祁连山构成青藏高原的北东边界, 是研究青藏高原的隆升与向内陆扩展的关键区域, 利用新生代湖相沉积的碳氧同位素组成估算祁连山古海拔对认识青藏高原的隆升有重要意义。在中祁连陆块不同地点出露的始新统、渐新统、中新统和中晚更新统分别取样并进行碳氧同位素分析, 估算相应地质时期的古年均温和古海拔高度。结果表明, 祁连山地区古近纪的海拔约为2711 m, 中新世早期的海拔为2848 m左右, 中新世中晚期祁连山海拔达到约3586 m, 中晚更新世祁连山的古海拔约为3790~3890 m。古近纪祁连山的海拔较低, 但已经构成了青藏高原的东北边界; 中新世中晚期祁连山强烈隆升, 形成了盆-山构造地貌格局; 第四纪祁连山地壳重新活跃并呈阶段性快速隆升, 河流堆积和侵蚀交替进行。根据碳氧同位素估算的祁连山古海拔高度变化为认识青藏高原隆升的过程提供参考。 |
| 中文关键词:碳氧同位素 古海拔 新生代 祁连山 |
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| Paleoelevation of the Qilian Mountain Inferred from Carbon and Oxygen Isotopes of Cenozoic Strata |
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| Abstract:Located at the northeast edge of the Tibetan Plateau, the Qilian Mountain is a key region where the whole Plateau expands to the interior of the continent, and hence the paleoelevation estimated by paleo-altimetry based on carbon and oxygen isotopes of Cenozoic strata is of great significance for understanding the uplift of the Tibetan Plateau. In this paper, such a paleo-altimetry was used to calculate the paleo-annual temperature and paleo-elevation of middle Qilian Mountain based on carbon and oxygen isotopes of Cenozoic sediments formed in the Eocene, Oligocene, Miocene and Mid-late Pleistocene. The results show that the Qilian Mountain was uplifted to 2711 m in Paleogene, to ~2848 m in the early Miocene, to ~3586 m in the mid-late Miocene, and to 3790~3890 m in the Middle-late Pleistocene. The paleo-elevation of the Qilian Mountain in Paleogene was not very high, but had already formed the northeastern margin of the Tibetan Plateau. The Qilian Mountain was uplifted considerably in Mid-late Miocene, forming basins-mountains tectonic landforms. In Quaternary the earth crust of the Qilian Mountain was activated again and uplifted intermittently. The paleoelevation of the Qilian Mountain inferred from carbon and oxygen isotopes of Cenozoic strata provides a reference for better understanding of the uplifting process of the Tibetan Plateau. |
| keywords:carbon and oxygen isotopes paleoelevation Cenozoic Qilian Mountain |
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