Abstract: Basin Analysis Constrains the Strike-slip History of the Altyn Tagh-Alxa-East Mongolia Fault System

YUE, YONGJUN, Stanford University, Department of Geological and Environmental Sciences, Stanford, CA

I established a correlation between the Beishan and the Inner Mongolia orogens north of the Qilian Shan, and suggested that the Altyn Tagh fault, which defines the northern margin of the Tibetan plateau, propagated to the NEE to join the presently inactive, NEE-NE trending Alxa-East Mongolia fault during its early stage of evolution (Oligocene to -13 Ma). This hypothesis predicts that the petroliferous Erlian basin south of the Alwa-East Mongolia fault may have been contiguous with the poorly explored Beishan-Huahai basin north of the fault before the Oligocene; they have been offset left-laterally for about 400 km.

I propose to investigate and correlate these two basins as a test for the above-mentioned hypothesis and to better constrain the strike-slip history of the Altyn Tagh-Alxa-East Mongolia fault system. The proposed project will carry out detailed measurements of the sedimentary formations, including depositional facies, paleocurrents, palynology, provenance analyses and biomarker determinations. The integrated facies and laboratory analyses of these two basins will be used to (1) establish a correlation between the Erlian and Beishan-Huahai basins, and therefore, further constrain the offset along the Altyn Tagh-Alxa-East Mongolia fault system; (2) provide constraints on the ages when the Altyn Tagh-Aixa-East Mongolia fault system initiated and when the Alxa-East Mongolia fault became inactive; and (3) quantitatively estimate the long-term slip rate during the early stage evolution of the fault system.

AAPG Search and Discovery Article #90931©1998 AAPG Foundation Grants-in-Aid