Abstract: Mohe Basin situates in the northern edge of Erguna massif and to the Mongolia-Okhotsk orogenic belt in north. Both Mohe Basin and Amur Basin in Russia belonged to the same basin in the Mesozoic. The Middle Jurassic of Mohe Basin includes Xiufeng Formation, Ershierzhan Formation, Emuer River Formation and Kaikukang Formation. According to the composition of gravel, debris and the heavy mineral of clastic rocks, it can be determined that the mother rocks are of mainly metamorphic rocks and intermediate-acid igneous rocks, few of sediments and basic igneous rocks. Taking the paleocurrent direction into account, the source of the sediments are in the south. Sediments were transported from multiple provenances, one provenance is the block-uplifted basement, and another is the opened magmatic arc. Comparing with the regional lithology, the block-uplifted basement may be from the Xinghuadukou Formation (Paleoproterozoic) and Xinglong Formation (Cambrian), the cut magmatic arc is related with the collision and post-collision granitic rocks of Paleozoic and acidic igneous rocks of Early Mesozoic. According to the supply of mother rock features, it is concluded that Mohe Basin in the Middle Jurassic period is not a typical foreland basin, but compressive flexure basin or intermountain basin under the setting of compression.

Key words: provenance analysis, Middle Jurassic, Mohe Basin