| 江汉盆地始新世滩坝砂沉积的物源分析及其对古气候的响应: 来自碎屑锆石的证据 |
| 投稿时间：2024-07-19 修订日期：2024-11-18 |
| 关键词:Beach bar sandstone, Provenance analysis, Response of paleoclimate, Zircon U-Pb dating, Jianghan Basin |
| 基金项目:国家自然科学基金项目（41502102，42130408，42072137） |
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| 摘要: |
| Provenance analysis of beach bar deposits in the Eocene in Jianghan Basin and their response to paleoclimate: Evidence from detrital zircon U-Pb ages |
| Exploration of unconventional oil and gas in recent years shows that Eocene is an important period for shale oil enrichment in Jianghan Basin, and beach-bar sandstone developed in thick mustone of Xingouzui Formation in Jiangling Sag is one of the favorable exploration targets in Jiangling Sag. .However, provenance of the beach-bar sandstone is still unclear due to the complex provenance system around the basin. In this paper, samples were collected from wells Hu5 and Y1 in the Xingouzui Formation of Jiangling Sag, and the detrital zircon U-Pb age test was carried out and compared with the zircon U-Pb age of the surrounding potential source area. The results show that the age spectra of these samples and previous detrital zircons have two main peaks of about 145 Ma and 440 Ma. By comparing with the potential provenance and Inverse Monte Carlo mixture model calculation, this study found that the southern provenance dominated by the main peaks of 147 Ma and 432 Ma of Xiangjiang River is the most important provenance in Jiangling Sag : the contribution of Xiangjiang River provenance accounts for 65 % ; Huarong uplift accounted for 25 % ; the Yuanjiang River accounts for 4 %, and the contribution of the northern Hanjiang River source to the basin is about 6 %. Combined with the paleoclimate changes in eastern China during the Eocene period and the development background of the depositional system in Jiangling Sag, it is most likely that the beach-bar sand in the Jiangling Sag is mainly derived from the Xiangjiang Delta in the south. Under the influence of the East Asian monsoon and related coastal current, part of sand in the Xiangjiang Delta was transported to the Jiangling Sag and deposit as widely distributed beach-bar sand. |
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