During the study of a large number of archaeological glass fragments, manganese-rich inclusions in leached layers were observed in a limited number of cases. This phenomenon occurs only in black-coloured leached layers. Since the formation mechanism of such manganese-rich inclusions is still unclear, a combination of several analytical techniques was used in order to investigate this phenomenon and, more specifically, to obtain more information on (a) the composition and morphology of the inclusions, (b) the chemical state of Mn and (c) the 3D morphology of the inclusions. A mechanism that might explain the formation of these inclusions is proposed.
Abstract In Palaeogene times, the ‘Southern Bight’ of the North Sea functioned as an intracratonic, shallow-marine, siliciclastic basin and accumulated a few hundred metres of gently dipping sediment packages. A fine-scale seismic-stratigraphical model for the Palaeogene was formulated on the basis of a dense, high-resolution reflection seismic grid. In total 13 major seismic-stratigraphical units were defined, based on geometry and seismic facies characteristics. The seismic stratigraphy has been complemented with the results of four cored wells near the Belgian coast, containing a nearly continuous, 200 m thick sediment succession of Eocene age. Facies analyses of these cores suggest that part of these sediments were deposited on a muddy shelf and part in adelta environment. Evidence from relevant onshore outcrops has been used to complete the geological history of the Palaeogene, with special emphasis on the Eocene. A sedimentation model for the Eocene is presented, and relative sea-level changes, regional tectonic events and changes in sediment input are discussed. Genetic interpretation of the various lithological units and the large-scale architecture of the ramp-type margin enable evaluation of sequence-stratigraphical concepts, initially defined for a typical shelf-slope-basin section along an Atlantic-type continental margin.
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