EasyGSH-DB: Crooked (1996, 2006, 2016)

Definition: The slate “Sk1” is a measure of the symmetry of the sum curve, which indicates how the ratio of coarse to fine parts in the grain distribution is. Folk & Ward (1957) quantify this symmetry in a range of values from -1 to 1. Positive values greater than 0 to 1 indicate a “left slate” for metrically represented sum curves, i.e. fine grain fractions outweigh in comparison to coarse fractions. Negative values less than 0 to -1 indicate a “right skeep” for metric sum curves, which indicates a predominance of coarse compared to fine fractions. Sk1 = 0 shows a perfectly symmetrical sum curve. Conclusions about the deposit environment can be drawn from the skew. Data generation: The basis for sedimentological evaluations are surface sediment samples, which were interpolated in the context of the EasyGSH project by means of anisotropic interpolation methods and taking into account hydrodynamic factors and erosion and sedimentation processes from individual samples of different years to a grid valid for one year. At each of these grid nodes, the sediment distribution is therefore available as a sum curve. For Deutsche Bucht, this basic product is available for 1996, 2006 and 2016 in a 100 m grid, for the exclusive economic zone of Germany for 1996 in a 250 m grid. Directly from these sum curves, the proportions required for the calculation rule for the Folk & Ward (1957) miscalculation can be calculated for the Sk1 parameter. Product: 100 m grid of the German Bay (1996, 2006, 2016) and 250 m grid of the Exclusive Economic Zone (1996), where the slate Sk1 to Folk & Ward (1957) is deposited at each grid node. The product is provided in GeoTiff format. Literature: Folk, R. L., and Ward, W. C. (1957). A study in the significance of grain size parameter. Journal of Petrology, 37, 327-354. For further information, please refer to the information portal (http://easygsh.wb.tu-harburg.de/) and the download portal (https://mdi-de.baw.de/easygsh/). English Download: The data for download can be found under References, where the data can be downloaded directly or via the web page redirection to the EasyGSH-DB portal. For further information, please refer to the download portal (https://mdi-de.baw.de/easygsh/EasyEN_index.html).