TEXTURAL PROVINCES AND TRANSPORT INTERPRETATIONS WITH FINE-GRAINED SEDIMENTS IN THE SKAGERRAK

The particle-size characteristics of 181 bottom samples from the Skage rrak and northernmost Kattegat have been evaluated with statistical an d graphical approaches. Regional provinces, defined by trends in distr ibution parameters, triangle-plot clustering and frequency-curve shape s, vary in their inferred sedimentation processes. The partitioning of particle-size distributions is based upon the observed tendency for f ine silt and clay to have limited sorting due to their deposition from aggregated suspensions. These partitioned subpopulations further allo w the consideration of sequential changes in distribution parameters a long possible transport paths. The methodology for deriving sediment t ransport paths is reviewed and modified with consideration of fine-gra ined sedimentation, including the complications induced by aggregation and the existence of both traction and suspension mechanisms. The par titioned fine fractions gave the most reliable trends, perhaps because of the consistency of suspension transport with respect to the large distances between sites. Fining trends with increased sorting and coar se skewness are documented toward deeper or more sheltered sites, espe cially in the Norwegian Trench, The coarse-fraction trends are more va riable and, like the distribution of the total sample, may be highly v ulnerable to the conflicting influence of suspension and traction mech anisms, imperfectly isolated in this fraction. Transport vectors are v aluable additions to basin modelling, but the assumptions involved in their interpretation suggest that additional information will normally be necessary to confidently interpret the details of sediment dynamic s and transport directions. Because of their interdependency with many environmental parameters, textural characteristics and sedimentologic provinces provide a framework for evaluation of both large- and small -scale processes.