The Editor, Journal of Glaciology

Sir,

I do not wish to enter into a public controversy with W. Haeberli about the origin of rock glaciers; he has always been deaf to my arguments. Nevertheless, the readers of his passionate assertions (Reference HaeberliHaeberli, 1989) must be aware that he intentionally omits to quote my detailed observations in the dry Andes (Reference LliboutryLliboutry, 1955, Reference Lliboutry1965, Reference Lliboutry1986). The concept that many rock glaciers come from old glaciers, or from “buried glacierets” (i.e. debris-rich glacierets, entirely covered at the end of the ablation season, and not nourished by ice every year) is not at all “purely speculative”, as he says. If an interested glaciologist comes to Grenoble, I can show him the aerial photograph coverage of the area that 1 have studied, with scores of such rock glaciers.

I do not deny that many (not all) rock glaciers are below melting point at depth. In this case, they consist of permafrost, but should slide on unfrozen ground …. Nevertheless, for the advancement of science, the essential point is not “must rock glaciers be left to scientists claiming to be permafrost specialists” but “what can we learn from the existence of rock glaciers in a given area”? I maintain that the geographical study of rock glaciers as an extreme case of glacier fluctuations, as an indicator of favourable mass balances in the past, or of past surges, would be much more rewarding than to consider them as a mere case of standard permafrost, or of creeping regolith.