Review: Zeitschrift für Geomorphologie 52/3 top ↑
The first three papers present methods for field measurements of platform surfaces and cliff retreat, and laboratory simulation of inter-tidal weathering and erosion processes. J. O. H.Swantesson, C. A. Moses, G. E. Berg & K. M. Jansson outline detailed micro-erosion measurements with micro-erosion meters (MEMs) and with laser scanners at twenty coastal sites on rocky shore platforms along the European Atlantic coast. As a result of repeated measurements between 1999 and 2001, different annual micro-erosion rates and their dependency on exposure to the sea and rock types are shown. For predicting platform downwearing rates C. A. Moses, D. A.Robinson, R. B. G.Williams & F. M. S.F.Marques present the results of laboratory simulation experiments of rock weathering and abrasion processes. A simple and cost-effective procedure of measuring sea-cliff retreat from aerial photographs is described by F. M. S.F.Marques.
The five subsequent papers deal with processes of shore-platform morphologies and evolution. A.Hènaff, Y.Lageat & S. Costa give an excellent geomorphological description of shore platforms on both sides of the English Channel and discuss the complex interactions of different processes, which influence shore-platform morphology and the evolution of cliff/platform systems.Y.Foote, E. Plessis, D. A.Robinson, A.Hénaff & S. Costa present the results of field measurements of surface erosion on chalk-shore platform at both sides of the English Channel. They describe significant differences of erosion rates in both space and time. Shore platforms in two contrasting micro-tidal, low wave energy environments (Mallorcan, Catalonian and Swedish coast) are described by L. Gómesz-Pujol, E. M.Cruslock, J. J.Fornós, & J. O. H.Swantesson. They state that in these environments the characteristics of present-day platforms apparently depend on factors other than wave exposure and rock resistance, and they assume that dominant factors are such as inheritance and rates of uplift. J. O. H.Swantesson, L. Gómez-Pujol, E. M.Cruslock, J. J.Fornós & P. Balaguer present processes and patterns of erosion on micro-tidal coastal sections in Sweden and in the western Mediterranean between 1999 and 2001, using micro erosion meter (MEM) and laser scanning measurements. They state that faster erosion rates observed in carbonate rocks in the investigated western Mediterranean coastal sites can mainly be ascribed to greater bioerosion and higher salinity of the seawater. Species-specific bioerosion rates on Mallorcan carbonate coasts are investigated by J. J.Fornós, G. X.Pons, L. Gómez-Pujol & P. Balaguer. The authors point out that actual erosion rates of the two most common bioerosive species Melaraphe neritoides and Patella sp. depend more on the abundance of these species than on rock density and texture.
The last four papers deal with studies of processes and patterns of cliff retreat and the role of shingle beaches. Y.Lageat, A.Hénaff & S. Costa describe erosion processes and cliff retreat of the chalk cliffs at the Normandy coast, where rockfall and rockslides are the basic driving mechanism of cliff recession. They emphasize that the loss of protective shingle material in front of the cliffs may result in a significant increase of cliff erosion. The contribution of gravel beaches to the dynamics of coastal cliff-shore platform systems at the chalk cliffs of NW France are illustrated by S. Costa, A.Hénaff & Y. Lageat. The authors discuss the complex inter-relationships between cliff retreat, widening of shore platforms and the role of gravel beaches, and consider the influence of the coastal sedimentary budget as well as the impact of recent human action and longer-term geological inheritance. Based on historical map data and digital elevation models U. Dornbusch, D. A.Robinson, C. A. Moses & R. B. G.Williams present measurements of cliff erosion and shore platform downwearing at the chalky coast of East Sussex. The authors have used the flint content of the chalk outcrops in the cliff to calculate its contribution to the shingle budget in Sussex. They assume that the shingle beaches are fossil deposits and not a product of Holocene cliff erosion. In the final paper F. M. S.F.Marques reports erosion rates, types, pattern, timing, magnitude and frequency of sea cliff retreat phenomena at three coastal sites on the west coast of Portugal over short-term (1999–2003) and medium-term (1947–2000) regional scales. Cliff retreat data and the estimation of sediment volumina were made by comparisons of aerial photographs and by comparisons of pairs of stereoscopic field photos of the cliff faces.
The volume excellently presents some of the activities of the European Shore Platforms Erosional Dynamics project-group and provides an interesting access to different aspects of shore-platform evolution and cliff retreat in rocky shore environments. The volume offers many impressive details of investigation methods, patterns, timing and the extent of shore platform dynamics, which are illustrated at a wide variety of European coastal sites. The volume is a great help in concerns understanding the processes, the patterns and inter-relationships between cliff erosion, shore platform evolution and shingle beach formation, and will be a good starting point for ongoing research.
Gerhard Schellmann, Bamberg
Zeitschrift für Geomorphologie 52/3