1�� College of Earth Sciences��Jilin University��Changchun 130061��China 2�� School of Earth and Space Sciences��Peking University��Beijing 100871��China

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 Timan- 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 paleobiogeographic 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 enough 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��