New evidences on the marine Holocene in the western Belgian coastal plain

Investigations in the coastal plain yielded new data regarding the stratigraphy of the marine Holocene and the evolution of the plain during the Atlantic and Subboreal periods. Formerly it was accepted that the Calais sediments were deposited during one single transgression. However at least four distinct transgressions were found belonging to the Calias Member. By means of 14C datings the development of the western coastal area is briefly considered

Geological considerations on the effect of sea-level rise on coastal lowlands, in particular in developing countries = Geologische bedenkingen betreffende de invloed van de zeespiegelstijging in lage kustgebieden, in het bijzonder in ontwikkelingslanden

The coastal lowlands of developing countries in particular are among the most densely populated and economically productive. Therefore, it is essential to get a realistic appraisal of the likely response of these areas to the predicted sea-level rise due to global warming. A short review of the different factors causing sea-level rise is presented and shows that the conception of global sea level must be abandoned. The method - ol ogies used to assess the impact of a sea-level rise are critically evaluated whereby it is noticed that the coastal processes and the controlling factors are not sufficiently considered. The geological history of the last 10,000 years of deltas and estuaries provides an analogue of the way coastal lowlands may respond to the predicted sea-level rise, and indic ates that these areas will be able to keep pace with the predicted rate of sea-level rise providing that sufficient sediment is continuously available and dikes are absent. The high rate of human-induced subsidence in big cities is a far more devastating problem than the effects of sea-level rise

Planning and geology in a coastal plain

Holocene coastal plain deposits are characterized by frequent lateral and vertical facies changes. From a geotechnical point of view, the deposits are very sensitive to compaction, because the moisture content is very high and the bearing capacity very low. These characteristics are at the origin of many technical (and financial) problems when buildings and infrastructural elements are constructed. However, when considering land-use planning with regard to the geological setting, many problems can be avoided. Two examples of road planning, and construction in relation to the occurrence of sand-filled channels are discussed, using profiletype maps as a basic source of informatio