Quaternary glacial sediments, glaciation style, climate and uplift in the Karakoram and northwest Himalaya: review and speculations

Opinions on the extent and style of the Quaternary glaciations of the Karakoram and northwest Himalaya have ranged from restricted alpine-style glaciation to extensive inundation by montane ice caps, to overwhelming by sheet ice from the Qinghai-Xizang (Tibet) Plateau. The sedimentological and geomorphological evidence underpinning these contrasting opinions is used to integrate the sedimentary record with what is known about uplift and incision rates and broad-scale changes in the regional climate. By reference to the independent record of monsoon-versuswesterly strength provided by the lacustrine and loess record of central and east Asia, increasing relative relief and topographical discordance are considered as influences upon glaciation style, glacier extents, and sediment budgets since the Middle Pleistocene. Ice extent may have progressively declined with increasing constraints on glaciation limits through time, but total ice volumes during glaciations may have shown less variation as valley systems enlarged in conditions of quasi-balance between uplift and incision.