Publication Date:
2018-02-01
Description:
A distinctive NNE trending belt of shortening structures dominates the topography and deformation of the eastern Sichuan Basin, ~300 km east of the Tibetan Plateau. Debate continues as to whether the structures resulted from Cenozoic eastward growth of the Tibetan Plateau. A low-temperature thermochronology (AFT and AHe) data set from four deep boreholes and adjacent outcrops intersecting a branch of the shortening structures indicates distinctive differential cooling at ~35–28 Ma across the structure, where stratigraphy has been offset vertically by ~0.8–1.3 km. This result forms the first quantitative evidence for the existence of a late Eocene-Oligocene phase of shortening in the eastern Sichuan Basin, synchronous with the early phase of eastward growth and extrusion of the Tibetan Plateau. Further, a compilation of regional Cenozoic structures reveals a Miocene retreat of deformation from the foreland basin to the hinterland areas. Such a tectonic reorganization indicates that Eocene to Miocene deformation in the eastern Tibetan Plateau is out-of-sequence and was probably triggered by enhanced erosion in the eastern Tibetan Plateau. ©2018. American Geophysical Union. All Rights Reserved.
Print ISSN:
2169-9313
Electronic ISSN:
2169-9356
Topics:
Geosciences
,
Physics
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