Distribution, ecology and taphonomy of the organism trace, Scolicia, in northeast Atlantic deep-sea sediments

The organism burrow, Scolicia, was studied in deep-sea sediment cores from several regions of the northeast Atlantic, including the Iceland–Faeroe Ridge, Rockall Plateau and Reykjanes Ridge. The data comprised sedimentological and physical measurements and X-ray radiographs. Scolicia generally can be observed only in radiographs. Grain size and sorting of sediments control the distribution of the echinoids that produce Scolicia. If developed under optimum ecological conditions in well-sorted coarse silts to fine sands, Scolicia dominates the biogenic structures with its very characteristic ichnofabrics. Its distribution pattern is influenced mainly by bottom currents, sedimentation rate and the faunal association. Indirectly, a dependence on water depth also seems to exist. The preservation and recognition of Scolicia in lithified sediments needs special conditions. These include restricted competition by organisms of the deeper-burrowing tiers, its generation within the optimum sediment grain size, or its production at the sand–silt/mud interface.