Fossil polygonal periglacial structures in Flanders (Belgium)

• Main Authors: Heyse, Irenée, Ghysels, Gunther
• Other Authors: Phillips, M, Springman, SM, Arenson, LU
• Format: Conference Object
• Language: English
• Published: Balkema 2003
• Subjects: Earth and Environmental Sciences; WESTERN; FROST WEDGE CASTS; JUTLAND; CANADA; Canada; Ice; permafrost; wedge*
• Online Access: https://biblio.ugent.be/publication/403384; http://hdl.handle.net/1854/LU-403384

A systematic survey of aerial photographs in Flanders reveals an ephemeral visible polygonal pattern on the dissected plateau between the Coastal Plain and the Flemish Valley. The paper describes the characteristics of this pattern and discusses the origin and the age of these phenomena. The study is based on a comparative study of the literature, the analysis of aerial photographs, coupled with intensive fieldwork based on excavations. The spatial distribution of the sites, the visibility and the spatial structure of the patterns are described. Based on air photos the borders of the polygonal patterns were reconstructed and trenches were excavated in order to find underlying field evidence. The pattern corresponds with the infillings of frost wedges and excavated structures show characteristics of composite and ice-wedge pseudomorphs. The structures suggest formation in a continuous permafrost environment as a result of thermal contraction cracking. These features have been constrained to the period between the Elstenian and Weichelian, but are most probably of Late Pleistocene age.