Late Cenozoic Basin Evolution along the Yellow River Corridor, Qinhai Province, China and the Development of the NE Tibetan Plateau

Xiangyang Xie 
Department of Geology and Geophysics, University of Wyoming
Laramie, WY
[email protected]

Growth and partitioning of the NE part of the Tibetan Plateau, central China, is documented by the formation, and subsequent erosion, of intermontane basins along the Yellow River. Long exposures of Neogene strata in the Xun Hua, Guide, and Gonghe basins, coupled with published bio- and magnetostratigraphy, provide a record of the interplay between mountain building and the formation of large lakes and an integrated river system over the last 3.58 Ma. Early basin history shows that a single, large, lacustrine system existed in which siltstones and mudstones were deposited. Geologic mismatches suggest that the large basin broke into a series of smaller, isolated lake basins as faults stepped across the region during growth of the Tibetan Plateau. Preliminary observations indicate that over time fluvial systems, mostly braided streams, migrated into the basins from the northern basin-margin uplift. Eventually these streams integrated into a single through-flowing river – the ancestral Yellow River. The time of first appearance of upstream-derived Yellow River detritus varies between the subbasins, indicating the ancestral river did not follow the present position of the Yellow River Gorge. Instead, the first appearance follows an irregular pattern among the basins suggesting that the Yellow River was strongly shifted by local growth of adjacent ranges. Thus, even one of the world’s largest rivers has been unable to maintain its position during active mountain building.

AAPG Search and Discovery Article #90033©2004 AAPG Foundation Grants-in-Aid