Stratified slope deposits: periglacial and other processes involved
Stratified slope deposits occur on or at the base of slopes within a wide range of hilly or mountainous environments. Gelifraction, a lack of vegetation, and snowmelt-derived slopewash are thought to be important factors in their development. The relatively fine-grained grèzes litées found at many sites within the French Charente region are the prototype of this kind of deposit. The original, strictly limited and genetically intended definition has been enlarged by mainly non-French authors causing considerable confusion.
Other assemblages of cold-climate slope deposits are more heterogeneous, sometimes less clearly stratified, and show much larger variation in grain sizes and sedimentary structures than grèzes litées. The most important of these are stone-banked solifluction (sheets or lobes), rock fall, (dry) grain flow, frost-coated clast flow, debris flow, snow avalanching and, to a lesser degree, rain-generated overland flow and (niveo-) aeolian activity. Many of these processes are azonal and occur under a wide range of environmental conditions. A periglacial context may nevertheless influence process activity in these cases, for instance with regard to their magnitude and/or frequency.