Composite Stratigraphy of the Sailinhudong Group and Ore-bearing Micrite Mounds in the Bayan Obo Deposits,Inner Mongolia,China

查看全文 作　　者：Qiao Xiufu, Gao Linzhi, Peng Yang,Institute of Geology, Chinese Academy of Geological Sciences,26 Baiwanzhuang Rd., Fuchengmenwai, Beijing 100037and Zhang Yuxu Chinese Academy of Geological Sciences, Beijing 100037 Gao Linzhi 出　　处：《Acta Geologica Sinica(English Edition)》索引1997年第71卷第4期,共15页 基　　金：This research was jointly supported by the National Natural Science Foundation of China (Grant No. 4962008);the 'Sequence Sea Level Change'-a state key project of the State Science and Technology Commission 摘　　要：Based on studies of sequence stratigraphy, event stratigraphy, biostratigraphy and lithostratigraphy, it is concluded that the Sailinhudong Group is a part of the Bayan Obo Group. Some trilobite fragments are first found in thin sections of the rock from the lower part of the Sailinhudong Group and some Ordovician acritarchs and chitinozoans are also found in this group. A formationa unit of carbonate seismites is first recognized in the upper part and a huge micrite mound is first identified at the top. Dolomite, the host rock of the super giant Bayan Obo Fe-Nb-REE deposits, is neither an igneous carbonatite nor a common bedded sedimentary carbonate, but a huge micrite mound. It has the same macroscopic characters as the micrite mounds at the top of the Sailinhudong Group, which suggests that they should be of the same horizon. According to the fossils, the Sailinhudong and Bayan Obo Groups should be of the Early Palaeozoic rather than the Middle Proterozoic. The new discovery and new idea will throw 关 键 词：Sailinhudong GROUP Bayan OBO GROUP SEISMITE MICRITE mound