| 柴达木盆地东缘中新世盆山系统演化与构造古地貌重建 |
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| 关键词:eastern Qaidam basin Wulan basin Miocene Youshashan Formation provenance analysis structural geomorphy |
| 基金项目:中国地质调查项目(编号: DD20190011);中国地质科学院基本科研业务费专项经费(编号: YWF201908);国家自然科学基金(编号: 41902116) |
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| Miocene Evolution of the Basin-mountain System and Paleogeomorphic Reconstruction in the Easternmost Qaidam Basin |
| The easternmost Qaidam Basin adjoins the intersection of the North Qaidam fault system (NQF) and the Elashan structural belt (ESB). The infilling process of Miocene sedimentary basins developed in this area must provide constraints on the uplifting history of their peripheral mountain belts. The well-preserved Wulan and Chacha basins were studied by sedimentology and provenance analysis, revealing two-stage geomorphic evolution history during the Miocene in the study area. At the first stage (~20–15 Ma), the Wulan basin performed as a typical intermountain flexural basin and mainly consists of braided river and delta depositional associations. These sediments were mainly fed by the persistently unroofed NQF, which means that another potential source area of the ESB had not yet been notably exhumed. By contrast, the Chacha basin is considered as a piggy-back basin and accommodated a stable braided river depositional system. These sediments were transported by eastward-flowing longitudinal rivers that originated from the western part of NQF and finally flowed into the Gonghe basin via the Maoniushan region. All these information supports the idea that the eastern Qaidam basin was once connected with the Gonghe basin during the early Miocene. At the second stage (~15–8 Ma), responding to the regional left-lateral shearing, the peripheral mountain belts of the Wulan basin, especially the ESB, uplifted simultaneously. This event broke the previous unified basin system and made the Wulan basin grade into a relative walled setting. Meanwhile, the intense activity of the Maoniushan fault led to the region where the Chacha basin occupied uplifted integrally, which seems to have been responsible for the absence of the coeval sediments. |
| WANG Yong-chao,CHEN Xuan-hua,SHAO Zhao-gang,YU Wei,SU He.2021.Miocene Evolution of the Basin-mountain System and Paleogeomorphic Reconstruction in the Easternmost Qaidam Basin[J].Acta Geoscientica Sinica,42(1):43-54. |
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