Structural records of the Late Cretaceous–Cenozoic extension in Eastern China and the kinematics of the Southern Tan-Lu and Qinling Fault Zone (Anhui and Shaanxi provinces, PR China)

Our study of the Late Cretaceous–Cenozoic extension in Eastern China is a kinematic analysis of faults (≈ 1500 striated fault data, 175 stress solutions at 90 sites) that has permitted us to separate stress fields belonging to six tectonic events. A WNW–ESE extension (1) has affected Eastern China from the Campanian to the Late Palaeocene–Early Ypresian. Under this extension, the Qinling (QLFZ) and Southern Tan-Lu (STLFZ) Fault Zones have been dextral transtensional fault zones. A first transpressional event (2) (NNE–SSW shortening) has occurred during the Late Ypresian–Lower Lutetian; the QLFZ and the STLFZ have been dextral transpressional fault zones. A NE–SW extension (3) has affected the Weihe graben during the Palaeogene; after a second transpressional event (4), the NE–SW extension (5) has been rejuvenated during the Late Miocene and the QLFZ has been a normal fault zone again and the STLFZ a sinistral transtensional fault zone; synrift subsidence has occurred in the Weihe graben. The second transpressional event (4) (WNW–ESE shortening) has occurred during the Late Oligocene–Early Miocene, during a period of uplifting and exhumation. At that time, the STLFZ and the QLFZ have become sinistral transpressional fault zones. A period of extension (6) has taken place during the Late Pliocene–Quaternary; the extensional direction has trended ≈ NNW–SSE; during this event, the QLFZ has been a sinistral transtensional fault zone and the STLFZ a dextral transtensional fault zone. These results are compared with those previously published in order to evaluate the regional significance of these tectonic events.

► Six tectonic events occurred during Cretaceous–Cenozoic extension in Eastern China.
► QLFZ (Qinling Fault Zone) and STLFZ (South Tan Lu Fault Zone) have different motions.
► The tectonic story is connected with the geodynamic evolution of the eastern Asia.