Weathering in cold regions has primarily focused on the notion of ‘cold’, such that process and landform theory have generally used this both as the developmental criterion and as the outcome of palaeoenvironmental reconstructions based on landforms or sediments. As a result of this approach, the process focus in terms of weathering has been that mechanical processes predominate, with freeze-thaw weathering as the prime agent, and that chemical processes are temperature-inhibited, often to the point of nonoccurrence. Here a reconsideration of the whole conceptual framework of weathering in cold environments is undertaken. It is shown that, contrary to popular presentations, weathering, including chemical weathering, is not temperature-limited but rather is limited by moisture availability. Indeed, summer, and oft-times even winter, rock temperatures are more than adequate to support mechanical and chemical weathering if water is present. Where water is available it is clearly shown that chemical weathering can be a major component of the weathering regime. The argument is made that there is no zonality to cold environment weathering as none of the processes or process associations are unique to cold regions; indeed, many cold regions show similar weathering assemblages to those in hot arid regions. Process-form relationships are also questioned. The assumption of angularity with weathering in cold regions is questioned, all the more so as hot arid studies identify exactly the same angularity of debris form. Further, that all forms have to be angular is shown by field examples to be no more than an artefact of original unquestioning and oft-repeated assumptions, now over a century or more old. The argument is made that there is a strong need for the reconsideration of the nature of weathering in cold environments, that current theory should be questioned and challenged, and field observation undertaken within this revised frame of reference.

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Nivation and cryoplanation are deeply entrenched and widely invoked morphogenetic concepts within periglacial geomorphology. However, given their complexity and purported significance in landform development, neither has received the scientific scrutiny merited. Nivation is generally associated with the weathering and mass movement processes stemming from late-lying seasonal snow and the ensuing landforms. As a process suite it invokes mechanisms such as freeze-thaw weathering and solifluction. Cryoplanation also invokes a process suite, but one that also embraces nivation. Research in the last two or three decades has begun to provide a much sharper definition of nivation, but the available information is still inadequate for a central mechanism in periglacial landscapes. Cryoplanation is used to explain some benches, terraces and pediments that appear to be widespread in some periglacial environments: however, substantive field research on the mechanisms involved is all but absent. A case is presented for viewing nivation and cryoplanation as a single process spectrum much in need of state-of-the-art research.

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