Apatite fission-track data from upper Cretaceous formations in the Yuan'an Graben (China): Constraints on the timing of synsedimentary fault activity

Apatite fission-track signatures of upper Cretaceous Formations in the Yuan'an Graben are made to constraint on the timing of the Yuan'an and Tongchenghe synsedimentary fault activity. The apatite fission-track ages range from 102.0 ± 14.6 to 84.1 ± 3.7 Ma with P(χ²) >0.05; the mean confined track lengths of 14.18 ± 0.09 and 14.16 ± 0.08 μm with mean D_par values of 2.25 ± 0.02 and 2.26 ± 0.03 μm, respectively. These data are interpreted as dating their source-area exhumation, recording the exhumation and cooling of the footwall during major normal faulting. The results indicate that the timing of the Yuan'an and Tongchenghe synsedimentary fault activity occurred at 117–82 Ma and the intensive movement at 100–82 Ma; the onset time of extension in Jianghan Basin is ca. 117 Ma, which is related to the lithospheric extension associated with the subduction of the Pacific Plate beneath the Asian Plate. - Highlights: ► Apatite fission-track dating is used to constraint on the timing of fault activity. ► The onset time of extension in Jianghan Basin is ca. 117 Ma. ► Combination of AFT and ESR to determine a Graben evolution