Recent advances in the understanding of Quaternary periglacial features of the English Channel coastlands

• Published in: Journal of Quaternary Science
• Main Authors: Murton, Julian B., Lautridou, Jean‐Pierre
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2003
• Subjects: Raised Beach; Ice; permafrost
• Online Access: http://dx.doi.org/10.1002/jqs.748; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjqs.748; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jqs.748

Abstract Recent advances in the understanding of Quaternary periglaciation of the English Channel coastlands concern laboratory modelling of periglacial processes, dating of periglacial sediments and the distribution of permafrost during marine oxygen isotope stage (MOIS) 2. Modelling studies have successfully simulated (i) ice segregation in chalk in artificial permafrost, (ii) periglacial solifluction of natural slope sediments, and (iii) soft‐sediment deformation during thaw of ice‐rich soil. The resultant structures and deposits in these experiments have similarities with naturally brecciated chalk, solifluction deposits and involutions, respectively, along the English Channel coastlands, providing insights into their genesis and palaeoenvironmental significance. Dating of periglacial sediments is based on radiocarbon assays of organic material in head deposits, luminescence measurements of loess and coversand, and mammalian biostratigraphy in raised‐beach and associated slope deposits. Most age estimates fall within MOIS 2, although some are within MOIS 6 and possibly other cold stages. Maps reconstructing the distribution of permafrost during MOIS 2 vary in detail. The precise distribution of permafrost remains to be established owing to problems of (i) imprecise dating in the context of climatic instability, (ii) uncertain palaeoclimatic significance of particular periglacial structures and (iii) sparse data on the age and distribution of relict periglacial features. The wider significance of periglacial processes to the evolution of the Channel coastlands is speculated to involve rapid valley development by flowing water in areas of moist, frost‐susceptible bedrock that has been brecciated by ice segregation. Copyright © 2003 John Wiley & Sons, Ltd.