Upper Triassic-Jurassic Foreland Sequences of the Ordos Basin in China
Li Sitian, Yang Shigong, Tom Jerzykiewicz, 1995. "Upper Triassic-Jurassic Foreland Sequences of the Ordos Basin in China", Stratigraphic Evolution of Foreland Basins, Steven L. Dorobek, Gerald M. Ross
Download citation file:
The Ordos basin is one of the most important coal and hydrocarbon-bearing sedimentary basins in China. The sedimentary cover, which overlies crystalline basement, is subdivided into seven unconformity-bounded stratigraphic sequences. The Upper Triassic to Upper Jurassic sequences are interpreted to be of foreland basin deposits. Development of a rapidly subsiding foredeep, adjacent to the rising western and southern flanks of the Ordos basin, commenced in late Triassic time during the late phases of the Indosinian Orogeny. A lake which developed in the axial part of the foredeep was a site of sedimentation of organic-rich mudstones which are the major hydrocarbon source in the basin. The main, late Triassic phase of foreland deposition is represented by over 3,000 m of proximal, coarse-grained sediments interfingering with the lacustrine facies. Lacustrine fan deltas and steep-sloped deltas were the main sites of foreland deposition. The depositional history of the Ordos foreland basin includes an overfilled phase in early Jurassic time and changes of source area in late Jurassic time. Unlike the Mesozoic retroarc basins of North America, which developed under a generally unidirectional, west-east compressional regime, the Ordos foreland basin was developed under the influence of transpression related to collision in the Tethys tectonic domain of southwest China and the collision of North China and Yangtze blocks.
Foreland sedimentation was terminated in early Cretaceous time due to a continent-wide shift to an extensional tectonic regime.