Implications of Basin Segmentation: Analysis of Detrital Zircon Geochronology, Thermochronology, and Sandstone Petrography
Geology, Northern Arizona University, Flagstaff, AZ, USA
The northeast Tibetan Plateau has been the focus of research on the timing of tectonic deformation and associated basin evolution. Paleogene sedimentation in Linxia basin, located adjacent to the NE Tibetan Plateau was originally proposed to be the result of flexural subsidence of a broad foreland basin in response to movement on the north-directed West Qinling reverse fault to the south of the basin. This may have been in response to far-field stress related to Indo-Asian collision. However, recent flexural modeling based on decompacted sedimentary thicknesses from an E-W transect of measured stratigraphic sections perpendicular to the Jishi Shan mountain range yields an extremely low elastic thickness. This suggests that the subsidence mechanism in the Linxia basin from the late Eocene-Pliocene is not flexure. It has been hypothesized that the basin was disrupted, first by the uplift of the E-W trending Laji Shan during the early Miocene and subsequently partitioned by uplift of the N-S trending Jishi Shan in the middle Miocene. This episodic deformation makes systematic predictions about basin filling patterns, sediment provenance, depositional environments, and regional correlation of these elements in the Linxia basin. I will test these predictions through a basin-wide stratigraphic investigation of Linxia basin. I will test whether the locus and rate of subsidence and sediment accumulation are consistent with deposition in a foreland basin. Finally I will reconstruct the details of sediment sources, basin filling patterns, paleogeography, and paleoenvironments to determine what they imply about the timing and locus of basin formation and disruption.
AAPG Search and Discovery Article #90199 © 2014 AAPG Foundation 2014 Grants-in-Aid Projects