Archaeogeophysical studies at cortaillod and St. Blaise, Lac De Neuch??tel, Switzerland

Abstract

A sub-bottom profiler survey was conducted at offshore areas of Lac de Neuchǎtel in March, 1987. The objective was to characterize and understand the lacustrine geomorphology (sediments and geological features) at the archaeological sites of Cortaillod, Hauterive-Champréveyres, and St. Blaise by means other than systematic coring such as was carried out at Cortaillod-Est. Additionally, it allowed the optimum placement of subsequent cores. The high resolution acoustical profiling revealed several interesting geomorphological features such as relatively thick alluvial and colluvial sediments at the two sites of Cortaillod-Est and Les Esserts overlying glacial/post-glacial unconformities (formations). At St. Blaise-Hauterive, the southward trend of the Marin reef structure was found to be covered along much of its length with Holocene sediments, as were several suspected nearby stream channels or distributaries. These channels are completely filled with stratified sediments, most probably of Holocene origin. These channels may have been sub-aerially active in the early Post-Glacial and hence provide clues to the development of Lake Neuchǎtel in the early Holocene. The results of this study are the basis for future, more detailed, studies of these sediments as to their origin and composition.