ABSTRACT
The geomorphology of the Karakoram Himalaya is considered in terms of the altitudinal zonation of climatic-geomorphic conditions and their downslope relations. Factors of greatest importance are the large gradients of precipitation with elevation, temperature regimes including the seasonal migration of frequent freeze-thaw, and the duration of snow on the ground. These factors first result in a major erosional role of the downslope moisture stream from humid, high altitude areas to progressively drier, and eventually arid, areas at low altitudes. Avalanches, glacier flow and seasonal meltwaters each play a large part. Second, local forms and processes exhibit altitudinal zonation, which occurs in four broad belts. Attention is directed to conditions 3000-6000 m in altitude in the central Karakoram and in the Biafo and Barpu-Bualtar glacier basins. Here the landscape is a combination of extensive glacier ablation zones and off-glacier slopes. Moisture supply, including seasonal meltwater production, and freezethaw cycles are abundant. It is a landscape dominated, on the one hand, by rock walls and ridges and, on the other, by glacier ablation zones. The best-developed depositional features occur at the interface between glacier margins and off-ice areas. Distinctive systems of deposits follow the margins of the glaciers but depend upon slope, snowmelt, and lacustrine processes, and ice margin activity. They also reflect the variations and relations of these processes as a function of elevation. Both glacier fluctuations and changes in climatic-geomorphic conditions with elevation have relevance to late Pleistocene and Holocene developments and their depositional legacy.
