- 责任者：Zhang Yuanze (State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Wuhan 430074 ; China) ; Wang Guocan
- 刊名：Earth Science
- 出版年：2013
- 卷期：38(4)
- 页码：p.725-744
- issnNo：ISSN1000-2383
- isbnNo：CN42-1233/P
Xunhua-Hualong basin Cenozoic sedimentary strata, basement and surrounding mountains analysis of apatite fission track geochronology reveals the Northeast margin of Qinghai-Tibet plateau experienced three periods of uplift and exhumation events since Late Cretaceoushansi-font-family: Calibri; mso-fareast-font-family: 宋体; mso-ascii-theme-font: minor-latin; mso-fareast-theme-font: minor-fareast; mso-hansi-theme-font: minor-latin">： hansi-font-family: Calibri; mso-fareast-font-family: 宋体; mso-ascii-theme-font: minor-latin; mso-fareast-theme-font: minor-fareast; mso-hansi-theme-font: minor-latin">（1hansi-font-family: Calibri; mso-fareast-font-family: 宋体; mso-ascii-theme-font: minor-latin; mso-fareast-theme-font: minor-fareast; mso-hansi-theme-font: minor-latin">） Basin basement, Laji mountain and West Qinling orogenic belt apatite fission track ages gen- erally record a Irate Cretaceous-Eocene relatively rapid regional uplift and exhumation event. Northern margin of West Qinling rapidly uplift at 84 Ma, which was controlled by the uplift of the northward thrust; to the North Lamu Gorge in central of Xun- hua-Hualong basin uplift at 69 Ma~ further north rapid uplift stages along Laji mountain is mainly between 40--50 Ma, reflec- ting Paleocene-Eocene rapid uplift gradually extending from south to north. This tectonic uplift event resulted in Xunhua- Hualong basin and Linxia basin missing Paleogene Xining group sedimentary strata that deposits in northern Xining-Minhe ba-sin. The first period of uplift and exhumation ended at about 31 Ma, when Xunhua-Hualong basin connected with eastern Linxia basin to a large unified foreland basin of West Qinling, both experience the same tectonic and sedimentary evolution history, therefore Cenozoic oldest Tala group sedimentary strata age in Xunhua-Hualong basin wonhansi-font-family: Calibri; mso-fareast-font-family: 宋体; mso-ascii-theme-font: minor-latin; mso-fareast-theme-font: minor-fareast; mso-hansi-theme-font: minor-latin">＇t exceed the oldest sedimentary stra- ta with Paleomagnetic age of 29 Ma in Linxia basin. hansi-font-family: Calibri; mso-fareast-font-family: 宋体; mso-ascii-theme-font: minor-latin; mso-fareast-theme-font: minor-fareast; mso-hansi-theme-font: minor-latin">（2hansi-font-family: Calibri; mso-fareast-font-family: 宋体; mso-ascii-theme-font: minor-latin; mso-fareast-theme-font: minor-fareast; mso-hansi-theme-font: minor-latin">） Late Oligocene about 26 Ma Laji mountain began bi-directionally thrust-uplift and may have continued to Early Miocene about 21 Ma, and uplifting made Xunhua-Hualong basin become pied- mont extrusion foreland basin between Laji mountain and West Qinling, when Xunhua-Hualong basin began to deposit Tala group alluvial fan of thick coarse clastic rocks. By analyzing sedimentary facies, the ancient flow direction and gravel composi- tion of Xianshuihe group and I.inxia group sedimentary strata in Xunhua-Hualong basin, it is concluded that Laji mountains ex- perienced the largest bi-directional thrust-uplift event in the Miocene about 8 Ma, which led directly to the event of Xunhua- Hualong piedmont extrusion foreland basin turning into mountain basin, which formed basic pattern of basin-mountain land- form in northeastern margin of Qinghai-Tibet plateau nowadays.