Flexural subsidence by 29 Ma on the NE edge of Tibet from the magnetostratigraphy of Linxia Basin, China

This study provides a detailed magnetostratigraphic record of subsidence in the Linxia Basin, documenting a 27 Myr long sedimentary record from the northeastern edge of the Tibetan Plateau. Deposition in the Linxia Basin began at V29 Ma and continued nearly uninterruptedly until V1.7 Ma. Increasing rates of subsidence between 29 and 6 Ma in the Linxia Basin suggest deposition in the foredeep portion of a flexural basin and constrain the timing of shortening in the northeastern margin of the plateau to Late Oligocene^Late Miocene time. By Late Miocene^Early Pliocene time, a decrease in subsidence rates in the Linxia Basin associated with thrust faulting and a V10‡ clockwise rotation in the basin indicates that the deformation front of the Tibetan plateau had propagated into the currently deforming region northeast of the plateau. 9 2003 Elsevier Science B.V. All rights reserved.