The age of the base of the Paleoproterozoic Hutuo Group in the Wutai Mountains area, North China Craton: SHRIMP zircon U-Pb dating of basaltic andesite  

作　　者：DU LiLin YANG ChongHui GUO JingHui WANG Wei REN LiuDong WAN YuSheng GENG YuanSheng 

机构地区：[1]Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China [2]Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China [3]Beijing SHRIMP Center, Beijing 100037, China

出　　处：《Chinese Science Bulletin》2010年第17期1782-1789,共8页

基　　金：supported by the Basic Foundation of Scientific Research Work from Ministry of Science and Technology of China (J0721 and J0907);National Commission on Stratigraphy of China (1212010511702-01);China Geological Survey (1212010611801)

摘　　要：Basalt and basaltic andesite metamorphosed at greenschist facies occurs with conglomerate layers at the bottom of the Paleoproterozoic Hutuo Group in the Wutai Mountains area, North China Craton. Detailed geological surveying confirms that these volcanic rocks are conformable within the neighboring sedimentary rocks. The SHRIMP results on basaltic andesite are divided into two groups. In one group the 207Pb/206Pb ages are from 2433 to 2558 Ma, which is consistent with the basement crustal age in Fuping and Wutai areas. In the other group, 13 grains yielded a weighted mean 207Pb/206Pb age of 2140±14 Ma. The latter is interpreted as the eruption age of the basaltic andesite, and gives the age of the base of the Hutuo Group. This result further suggests that the Hutuo Group formed in the middle Paleoproterozoic, not the early Palaeoproterozoic or late Archaean, as thought before, and is related to a 2.2-2.1 Ga rifting event in the Central North China Craton.Basalt and basaltic andesite metamorphosed at greenschist facies occurs with conglomerate layers at the bottom of the Paleoproterozoic Hutuo Group in the Wutai Mountains area, North China Craton. Detailed geological surveying confirms that these volcanic rocks are conformable within the neighboring sedimentary rocks. The SHRIMP results on basaltic andesite are divided into two groups. In one group the ^207pb/^206pb ages are from 2433 to 2558 Ma, which is consistent with the basement crustal age in Fuping and Wutai areas. In the other group, 13 grains yielded a weighted mean ^207pb/^206pb age of 2140±14 Ma. The latter is interpreted as the eruption age of the basaltic andesite, and gives the age of the base of the Hutuo Group. This result further suggests that the Hutuo Group formed in the middle Paleoproterozoic, not the early Palaeoproterozoic or late Archaean, as thought before, and is related to a 2.2-2.1 Ga rifting event in the Central North China Craton.

关 键 词：玄武安山岩 五台山地区 华北克拉通 古元古代 滹沱河 SHRIMP 同位素测年 中国 

分 类 号：P597.3[天文地球—地球化学]