Perennial frost mounds developed across northern Europe following retreat of the Late Quaternary ice sheets (>10 ka BP). Their relict forms comprise depressions with surrounding ramparts (Periglacial Ramparted Depressions - PRDs). Although PRD surface geometry is well-documented, their genetic origin is less well-understood. In addition, PRDs are sometimes difficult to identify because they are geomorphologically similar to features formed by non-frost processes (e.g. solution hollows, iceberg gravity craters).
Accurate identification of PRDs will:
- contribute to the understanding of mechanisms for PRD formation
- clarify the geological hazards they represent to the construction industry in terms of sediment compaction and subsidence
- inform Quaternary environmental reconstruction.
The desired output of this research is to establish the cryogenic origins of PRDs at sites in the UK and Belgium, by characterising their internal structures at macro- and micro-scales. Differences and similarities in structures informed by environmental settings will be confirmed, and identification of any characteristics diagnostic of specific PRDs will be considered; which will also contribute to developing an understanding of the potential relationship between different types of PRDs.
This research is based on a novel technique not previously utilised in the examination of PRDs: micromorphology. Micromorphology is considered the most effective and efficient approach in better understanding the characterisation and formation of PRDs, thus contributing to a developing body of knowledge.