论文摘要
Mesozoic strata in the Nanzhao and Mashiping basins recorded the tectonic evolution history of the Qinling Orogen（QO）. We presented new detrital zircon laser ablation–inductively coupled plasma–mass spectrometry U–Pb ages and in situ Hf isotopic data in order to constrain the depositional age and provenance of the Taishanmiao, Taizishan, Nanzhao, and Mashiping formations（from oldest to youngest） of the North QO（Fig. 1）. Detrital zircons from Taishanmiao and Taizishan formations within the Nanzhao Basin yield five（1855, 923, 732, 433, and 240 Ma） and seven main age populations（1938, 1858, 822, 729, 432, 303 and 218 Ma）, the eHf（t） values range from-20.2 to +7.6 and-15.0 to +6.8, respectively. In addition, detrital zircons from Nanzhao and Mashiping formations within Mashiping Basin have two（2270 and 117 Ma） and eight age populations（1850, 1629, 1418, 1282, 1110, 836, 440, and 122 Ma）, the eHf（t） values range from-17.3 to +3.5 and-24.9 to +9.7, respectively. Combined U-Pb ages, Hf isotopic compositions and age-diagnostic fossils, we proposed that the Taishanmiao and Taizishan formations formed during the late Triassic. The Nanzhao Formation deposited in the early Cretaceous rather than previous late Jurassic. The Mashiping Formation deposited during the early Cretaceous. Detrital zircons from late Triassic strata were generally derived from the North QO, the South QO, the North China Craton, and with a minor from the Xing-Meng Orogenic Belt. Nanzhao Formation were mainly sourced from the QO, and with only a minor contribution from the North China Craton basement. The early Cretaceous conglomerates of the Mashiping Formation were formed mainly from recycled earlier detritus. The provenance shift in the Mesozoic sediments indicates that the QO was strongly uplifted twice. The northward subduction of the Mianlue Ocean during the late Triassic and intracontinental subduction of the Yangtze Craton beneanth the QO and north thrusting of QO during the early Cretaceous caused the uplifted and erosion of the QO（Fig. 2）.
论文目录
文章来源
类型: 国际会议
作者: WANG Anqi,YANG Debin,YANG Haotian
来源: 第九届世界华人地质科学研讨会 2019-06-01
年度: 2019
分类: 基础科学
专业: 地质学,地质学,地质学,地质学
单位: College of Earth Sciences, Jilin UniversityKey Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Natural ResourcesKey Laboratory for Evolution of Past Life and Environment in Northeast Asia, Ministry of Education
分类号: P534.4;P597.3;P542
DOI: 10.26914/c.cnkihy.2019.028438
页码: 286-287
总页数: 2
文件大小: 212k
下载量: 1