Sediment distribution German North Sea - classification according to FOLK (1954, 1974)

The map on a scale of 1 : 250,000 represents the sediment distribution according to FOLK (1954, 1974). This is based on a percentage distribution of the three summarized grain size fractions gravel & cobbles, sand and silt & clay developed by FOLK (1974), which are subdivided into 15 classes in a triangular diagram. The map representation is based on sediment samples from the seafloor surface to a depth of 0.2 m and stratigraphic logs from boreholes at 0.2 m depth, which were available in the German North Sea area until November 2012. The basic data are stored in databases at the BSH and LBEG, and data collected in the future will be integrated into them. The map shows areas of similar unconsolidated sediments at the seafloor surface. Unconsolidated sediments are classified according to their grain size according to DIN EN 14688-1: Clay (grain size <0.002 mm); Silt (grain size 0.002 to 0.063 mm); Sand (grain size 0.063 to 2.0 mm); Gravel (grain size 2.0 to 63 mm); Cobbles and boulders (>63 mm). Based on the grain size analyses carried out in the laboratory and the layer descriptions from boreholes, grain size ranges are summarized for corresponding questions and then classified.本比例尺为1:250000的地图依据FOLK（1954、1974）提出的分类标准展示沉积物分布情况。该地图的数据基础为FOLK（1974）构建的三类汇总粒级的百分比分布方案，即砾石与圆砾、砂、粉砂与黏土，并在三角图中将其细分为15个类别。本次制图采用的数据源包括德国北海区域截至2012年11月可获取的海底表层0.2米以浅沉积物样品，以及深度0.2米处的钻孔地层测井资料。基础数据存储于BSH与LBEG的数据库中，后续收集的相关数据也将纳入该类数据库。该地图展示了海底表层松散沉积物的分布区域，松散沉积物依据DIN EN 14688-1标准按粒径进行分类：黏土（粒径<0.002 mm）、粉砂（粒径0.002~0.063 mm）、砂（粒径0.063~2.0 mm）、砾石（粒径2.0~63 mm）以及圆砾与巨砾（粒径>63 mm）。研究人员结合实验室粒度分析结果与钻孔地层描述信息，针对具体研究需求汇总粒度区间并完成分类。