Tectonic geomorphology, active tectonics and lower crustal channel flow hypothesis of the southeastern Tibetan Plateau

We use high-resolution SRTM DEMs to quantify the large scale topography and geomorphology in southeastern margin of the Tibetan Plateau. The southeastern plateau region is characterized as 'negative topography', i.e., a topography where there is an inverse or negative correlation between elevation and relief and between elevation and mean slope gradient. This is in sharp contrast with the positive topography in plateau interior, where elevation is positively correlated with relief and mean slope. High-elevation and low-relief (HELR) surface, which is preserved between large rivers in SE plateau, is generically linked to the low-relief surface in plateau interior and shows a gradual transition to less preservation because of southeastwardly increased river incision. The HELR surface appears to stop near the NE-trending Yalong thrust belt, which coincides with a 50~200 km wide relatively steep drop in elevation across this plateau margin. Morphometric analysis, in conjunction with recent studies on regional tec