A COMPLEX ASSEMBLAGE OF GLACIAL LANDFORMS SUGGESTS PAST REGIONAL ICE CAP STYLE GLACIATION IN PART OF THE SOUTHEASTERN TIBETAN PLATEAU

Glacial geomorphologic and chronologic studies of the Shaluli Shan (Shaluli Mountains) in the southeastern Tibetan Plateau provide evidence for multiple glaciations. Mapping and field observations indicate the presence in the past of ice caps and valley glaciers. This area is characterized by high mountains and relatively low relief high plateaus, surrounded by steep and deep fluvial valleys. Elevation primarily ranges between 4000 and 5000 m a.s.l.. The zonal pattern of glacial landforms on the low relief plateaus, including ice-scoured areas with lineations, roche moutonnées, and moraines and glacially-carved valleys fringing the plateau is similar to that created by paleo-ice sheets and ice caps in the Northern Hemisphere. The scoured areas and glacial lineations which are typical for ice cap glaciations only mapped on low relief granite plateaus and the patterns of these features as well as valley glacial landforms centered on the high mountain range indicates that topography had a strong influence on ice flow patterns. Finally, preserved saprolite juxtaposed with extensive erosional features on the plateau surfaces suggests to us the presence of a complex pattern of the basal thermal regime for the most recent paleo-ice cap, perhaps including areas of cold-based ice. Cosmogenic nuclide exposure ages for boulder and till samples indicate that major periods of glacial expansion included the global last glacial maximum, and three older glacial stages with minimum ages around 100 to 130 ka, 150 ka, and 180 ka.