Pleistocene paleosurface reconstruction and Holocen erosion quantity calculation for Guide—Gonghe—Tongde basin complex, Qinghai

Abstract

The Guide-Gonghe-Tongde basin complex is located along the northeast marginal zone of the Tibetan Plateau.The Yellow River flows through these three basins.For understanding the tectonic and climatic indications of the fluvial erosion of the three basins since Holocene,the authors calculated the erosion quantity by using geological cross sections combined with digital elevation model(DEM).First,the points selected for the interpolation were picked out manually from a series of geological profiles.The minimum Pleistocene surfaces were reconstructed within the basins.This method reduced the error caused by the erosion after the deposition.Second,the erosion quantity and the erosion rates since Holocene were obtained by subtracting the modern elevation from the reconstructed surface.The results show that the erosion rate increased from upstream basin(Tongde basin) to downstream basin(Guide basin).The spatial erosion differences may indicate that the uplift of the margin of the Tibetan Plateau was greater than that of the inner part of the plateau.