The Kungurian-Capitanian （Permian） Zhesi branchiopod fauna is mainly composed of cold-water typed taxa with high diversity and abundance. This fauna is similar with the coeval brachiopod faunas from Ti- man-Pechora,...The Kungurian-Capitanian （Permian） Zhesi branchiopod fauna is mainly composed of cold-water typed taxa with high diversity and abundance. This fauna is similar with the coeval brachiopod faunas from Ti- man-Pechora, Svalbard, and Queen Elizabeth Islands of the Boreal Realm, with no real ＂warm-water＂ species. Zhesi brachiopod fauna is a cold-water fauna and should be assigned to the Boreal Realm. Considering the paleogeographic characteristics of this fauna and the basic rationale of paleobiogeographie provinces being controlled by latitude-temperate, and that the above areas were located at 50°N -70°N in the global paleoclimate reconstruction map compiled by Boucot et al. , the paleo-latitude of the southern margin of Jiamusi-Mongolia Block, where developed the Zhesi brachiopod fauna, is suggested ranging from 40°N to 60°N. Zhesi brachiopod fauna is an endemic fauna, containing more than 75% endemic species and self-grouped as a biogeographic province, termed Inner Mongolia Province. These characteristics indicate that this area was closed or semiclosed at that time. On the Jiamusi-Mongolia Block, the Herlen-Jiamusi Old-land as an obvious ＂continental barrier＂ hindered the northward migration of the Zhesi brachiopod fauna and the immigration of brachiopod species from other areas. The Tarim plate has collided with the Kazakhstan plate and the western part of South Tianshan-Beishan-Xar Moron Ocean has been closed. At the same time, the western margin of Jiamusi-Mongolia Block was joined with the Tarim plate. The Xar Moron Ocean in south of Jiamusi-Mongolia Block was wide e- nough and the ocean temperature rose gradually southward, so that it is not suitable for the cold-water brachiopods to survive and thrive on the northern margin of the North China plate. Thus, the ocean with large width and high temperature formed another natural barrier for the southward migration of the cold-water brachiopods.展开更多
Through a sampling analysis of trace elements and REE in the section of Middle Permian Zhesi Formation in Solon area of Inner Mongolia,it is found that the overall sandstone and mudstone samples are characterized by L...Through a sampling analysis of trace elements and REE in the section of Middle Permian Zhesi Formation in Solon area of Inner Mongolia,it is found that the overall sandstone and mudstone samples are characterized by LREE-enrichment. By analysis of the discriminant index of the sedimentary environment,the tectonic setting of Zhesi Formation is determined to be a continental island arc environment. Meanwhile,according to the sedimentary structure and lithology combination,Zhesi Formation is divided into the neritic-bathyal retention-reduction environment as well as the delta front and prodelta sedimentary systems.展开更多
基金Supported by Project of China Geological Survey (No.1212011120153-3)
文摘The Kungurian-Capitanian （Permian） Zhesi branchiopod fauna is mainly composed of cold-water typed taxa with high diversity and abundance. This fauna is similar with the coeval brachiopod faunas from Ti- man-Pechora, Svalbard, and Queen Elizabeth Islands of the Boreal Realm, with no real ＂warm-water＂ species. Zhesi brachiopod fauna is a cold-water fauna and should be assigned to the Boreal Realm. Considering the paleogeographic characteristics of this fauna and the basic rationale of paleobiogeographie provinces being controlled by latitude-temperate, and that the above areas were located at 50°N -70°N in the global paleoclimate reconstruction map compiled by Boucot et al. , the paleo-latitude of the southern margin of Jiamusi-Mongolia Block, where developed the Zhesi brachiopod fauna, is suggested ranging from 40°N to 60°N. Zhesi brachiopod fauna is an endemic fauna, containing more than 75% endemic species and self-grouped as a biogeographic province, termed Inner Mongolia Province. These characteristics indicate that this area was closed or semiclosed at that time. On the Jiamusi-Mongolia Block, the Herlen-Jiamusi Old-land as an obvious ＂continental barrier＂ hindered the northward migration of the Zhesi brachiopod fauna and the immigration of brachiopod species from other areas. The Tarim plate has collided with the Kazakhstan plate and the western part of South Tianshan-Beishan-Xar Moron Ocean has been closed. At the same time, the western margin of Jiamusi-Mongolia Block was joined with the Tarim plate. The Xar Moron Ocean in south of Jiamusi-Mongolia Block was wide e- nough and the ocean temperature rose gradually southward, so that it is not suitable for the cold-water brachiopods to survive and thrive on the northern margin of the North China plate. Thus, the ocean with large width and high temperature formed another natural barrier for the southward migration of the cold-water brachiopods.
文摘Through a sampling analysis of trace elements and REE in the section of Middle Permian Zhesi Formation in Solon area of Inner Mongolia,it is found that the overall sandstone and mudstone samples are characterized by LREE-enrichment. By analysis of the discriminant index of the sedimentary environment,the tectonic setting of Zhesi Formation is determined to be a continental island arc environment. Meanwhile,according to the sedimentary structure and lithology combination,Zhesi Formation is divided into the neritic-bathyal retention-reduction environment as well as the delta front and prodelta sedimentary systems.
