Thrusting and exhumation processes of a bounding mountain belt: Constraints from sediment provenance analysis of the Hefei basin

Lithic (or gravel) composition analyses of the Jurassic Sanjianpu Formation and Fenghuangtai Formation in the Hefei basin show that the sediment prove nance consists mainly of four kinds of rock units: the basement metamorphic complex, granitic rocks, medium- and low-grade metamorphic rocks, and sand y and muddy sedimentary rocks, which are distributed along the bounding thr ust belt. The whole stratigraphic section can be divided into 2 lithic sequ ences and 7 subsequences. The regular distribution and changes of lithic fr agments and gravels in lithic (or gravel) sequences reflect that the boundi ng thrust belt of basin has undergone 2 thrusting cycles and 7 thrusting ev ents. Lithic (or gravel) composition analyses of the basin fully reveal tha t the northern Dabie basement metamorphic complex was exhumed on the earth' s surface in the Middle and Late Jurassic, and extensive intermediate and a cid intrusive rocks were developed in the southern North Huaiyang qr northe rn Dabie Mountains during the basin's syndepositional stage.