西藏那曲南部早白垩世闪长玢岩LA-ICP-MS锆石U-Pb年龄

中国地质调查局成都地质调查中心,四川成都610081;2. 中国地质科学院研究生部,北京100037;3. 中国地质大学(北京) 地球科学与资源学院,北京100083;4. 中国地质大学 (武汉)/地质过程与矿产资源国家重点实验室,湖北武汉430074

Zircon LA-ICP-MS U-Pb age of Early Cretaceous ignimbrite in southern Nagqu, Tibet

Chengdu Center, China Geological Survey, Chengdu 610081, Sichuan, China;2. Graduate School of Chinese Academy of Geological Sciences ,Beijing 100037, China;3. School of Earth Sciences and Resources ,China University of Geosciences, Beijing 100083, China;4. State Key Laboratory of Geological Processes and Mineral Resources/China University of Geosciences,Wuhan 430074, Hubei, China

摘要: 北冈底斯带东部那曲地区存在中三叠世、中—晚侏罗世和晚白垩世岩浆活动,却鲜有早白垩世岩浆活动的报道。对北冈底斯带东部那曲地区的罗马区闪长玢岩进行了系统的采样研究,并对其中2件样品进行了LA-ICP-MS锆石U-Pb定年,结果分别为116.1Ma±0.4Ma和115.9Ma±0.5Ma,在误差范围内几乎一致,应该代表了其形成的时代。表明北冈底斯带东部地区亦存在早白垩世晚期岩浆活动,这对探讨北冈底斯带早白垩世的地质演化具有重要意义。
- LA-ICP-MS锆石U-Pb年龄 /
- 闪长玢岩 /
- 冈底斯 /
- 嘎加组
Abstract: In northern Gangdise belt, Middle Triassic, Middle-Late Jurassic and Late Cretaceous magmatic activities exist, but Early Cretaceous magmatic activity was rarely reported. The authors sampled and analyzed systematically andesite porphyrite from Luoma area of Nagqu, Tibet. Two of the samples were dated by LA-ICP-MS zircon U-Pb dating, and their ages are 116.1±0.4Ma and 115.9±0.5Ma respectively. These ages are almost consistent with each other within the acceptable error range, thus representing the formation age. The authors hold that the Early Cretaceous magmatic activity did exist in northern Gangdise belt, which is of great significance in the study of the Early Cretaceous geological evolution.
- zircon LA-ICP-MS U-Pb age /
- diorite porphyrite /
- Gangdise /
- Gajia Formation