Faunal distribution and composition of heterozoan carbonates of the inner shelf off southern Norway

Abstract

Based on their shell content, the coarse carbonate sands/gravels sampled from 13 to 39 m water depth from the Norwegian inner shelf are shown to belong to the heterozoan association of James. They are dominated mainly by molluscs, polychaetes, cirripeds and foraminifera. Some of the dead mollusc species found indicate an origin in shallow water rocky areas ( Mytilus edulis ) and algal and seagrass communities ( Rissoa parva ). On the other hand, other species are typical of an inner shelf ( Modiolus modiolus ). The presence of intertidal/shallow subtidal species on the inner shelf (down to 39 m depth) is interpreted as due to transport by currents or waves during storm events. Analyses of mollusc shell surfaces were also undertaken and show three types of texture: unaltered, corroded and polished. The latter two are an alteration of the ornament of the shells. The corroded texture is the dominant type on the mollusc shells. Another important feature of the mollusc shells is the high amount of microboring ...