Shanxi Rift System

The rift system is continuous with the Weihe Basin to the southwest, which became active during the Paleogene.

The west–east trending Weihe Basin has a mainly half-graben geometry, thickening southwards into the large normal faults that form the boundary on its southern side with the mountains of the Qinling orogenic belt.

[11] The maximum thickness of Cenozoic sedimentary fill in the basin is estimated to be in the range 4 to 6 km (2.5 to 3.7 mi).

[12] The Sanmenxia Basin trends WSW–ENE and lies between the Qinling orogenic belt to the south and the Zhongtiao Mountains to the north.

Despite their similarities the two basins appear to have remained separate until at least the late Pliocene, when they were connected by the Yellow River.

It contains a maximum thickness of over 5 km (3.1 mi) of sedimentary rocks, which extend back in age to the Late Miocene.

[14] The sequence thins northwards to a few hundred metres, with pre-Cenozoic basement rock locally exposed in the E'mei highlands.

[15] The maximum thickness of the upper Miocene to recent sedimentary fill is in the range 1.8 to 2.2 km (1.1 to 1.4 mi).

[8] It is markedly asymmetric with a maximum thickness developed against the Jiaocheng Fault to the northwest of about 3.8 km (2.4 mi), with a sedimentary fill ranging in age from Pliocene to recent.

[16] In some descriptions of the Shanxi Rift System, this basin name has been used to cover three sub-basins, the Dingxiang, Yuanping and Daixian.