Abstract：
Western branch of the Tan-Lu fault zone lies along the eastern boundary of the Qingdong Sag in Bohai Bay.The Tan-Lu faults consists of 4 left-step,en-echelon faults.They show normal faulting on cross-sections and local flower structures related to transtension or transpression.The Tan-Lu faults along the Qingdong Sag evolved from dextral normal faulting of Paleogene,reverse dextral faulting at the end of Paleogene,weak normal faulting of Neogene to reverse dextral faulting of Quaternary.The pre-existing Tan-Lu faults reacted as dextral normal faults under oblique N-S extension due to their lower strengths during Paleogene rifting,leading to formation of the 4 left-step,en-echelon faults at shallow levels.Paleogene deposition patterns in the sag were controlled by the Tan-Lu faults,NW-striking basement faults and E-W new normal faults.The Basin inversion at the end of Paleogene terminated development of the rifted basin and caused reverse dextral faulting of the Tan-Lu faults due to regional ENE-WSW compression.Weak faulting was associated with the Neogene depression related to lithospheric thermal subsidence,and the Tan-Lu faults show weak normal faulting.The Tan-Lu faults switched into reverse dextral faulting since the beginning of Quaternary.
. Cenozoic activity methods and evolution of the Tan-Lu fault zone in Bohai Bay:Evidence from the Qingdong Sag[J]. Chinese Journal of Geology, 2012, 47(4): 1130-1150.
2012, Vol. 47 
