Microclimatic weathering in 3D; an Arctic case study

• Main Authors: Mol, L., Clarke, L.
• Format: Conference Object
• Language: English
• Published: 2016
• Subjects: Arctic; Endalen; Svalbard
• Online Access: http://eprints.uwe.ac.uk/30905/; http://eprints.uwe.ac.uk/30905/1/Photogrammetry%20BSG%202016%20abstract.pdf

This study investigates the influence of microclimate on weathering behaviour of sedimentary stone in an Arctic environment. In situ weathering rates can be difficult to quantify because of inherited weathering and the complexity of uncontrolled conditions. Therefore 45 test stone blocks were placed around the Endalen catchment (Svalbard) which were measured (water absorption capacity, weight and surface hardness) and 3D scanned before the field season commenced. These blocks were spread over five different locations representing varying exposure levels and snow cover. Microclimate was monitored using high resolution temperature loggers. Three different sedimentary stone types were used; Ancaster limestone, Duke sandstone and Old Red sandstone which represent different levels of porosity and susceptibility to weathering processes. One third of the blocks was pre-weathered, one third of the blocks was treated twice with the pre-weathering method and one third was kept as freshly surfaces. This aids in understanding variable rates of contemporary weathering as influenced by pre-existing weathering of a rock surfaces. After 12 months of exposure the blocks were retrieved and remeasured. Photogrammetry was used to map and quantify the weathering patterns across each block. These results were then combined with the laboratory testing and the temperature logs. The results show the impact of decreased snow cover on weathering behaviour as well as the effect of ‘bombing’ of blocks by small fragments in areas of rapid cliff retreat. This study demonstrates the potential of increased use of photogrammetry in weathering studies as a tool for understanding small scale changes in rock surfaces in challenging environments.