Combining facts and physics-based concepts with objective treatment of landsystem relations for documenting viscous flow features (rock glaciers) in mountain permafrost: examples from Nuristan/Hindu Kush, Galena Creek (Absaroka Mountains) and Gruben (Swiss Alps)

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ABSTRACT Viscous creep features in perennially frozen, ice-supersaturated talus/debris, usually called ‘rock glaciers’, are characteristic phenomena of mountain permafrost. On behalf of the Global Network for Permafrost (GTN-P) as part of the Global Climate Observing System (GCOS), the International Permafrost Association (IPA) has developed an initiative to systematically inventory them at global scale, and to monitor their kinematics. Corresponding consensus-based guidelines (RGIK 2023) define precise mapping procedures underpinned by facts and physics-based concepts concerning the involved conditions, material properties, processes and spatiotemporal scales. The related, more or less complex landsystem relations are treated in a strictly objective/descriptive sense as spatial upslope connections or neighbourhood situations. Application of such principles helps with avoiding misinterpretations and confusion sometimes induced with direct, intuitive, genetic attribution of landform ‘origins’. This is illustrated for a case in Nuristan, eastern Hindu Kush, Afghanistan, where in-situ measurements are lacking. Permafrost can confidently be inferred to be abundant in the region. Numerous, often spectacular, millennia old, and still actively advancing rock glaciers can be recognized and clearly distinguished from down-wasting (debris-covered) glaciers. Comparison with long-term creep in permafrost at Galena Creek (Absaroka Mountains) and Gruben (Swiss Alps), where in-situ measured facts are available, confirm that the international guidelines for related inventorying and mapping are fully adequate and should strictly be adhered to.