Grain-size statistics on sediment cores from residual dune ridge (North Sea, Island of Sylt)@en

Samples for grain-size analyses from residual dune ridges were obtained using a vibracore system equipped with a window sampler (diameter 50 mm, probe length 100 cm). The spectrum of the sediment grain sizes was measured using a Sympatec Helos KF Magic laser particle-size analyser (measuring range 0.5/18-3500 µm). Prior to measurement, samples were treated with hydrogen peroxide and acetic acid to oxidize the organic fraction and to dissolve carbonate particles, respectively. For measurement, samples were suspended in water using tetra-sodium diphosphate decahydrate as dispersing agent. Grain-size statistics were calculated using Gradistat (Blott and Pye, 2001) and are based on the graphical method (Folk and Ward, 1957) as applied to the metrical scale (see Blott and Pye, 2001 for details and equations).残余沙丘脊的粒度分析样本，通过搭载开窗取样器（直径50毫米、探头长度100厘米）的振动取芯系统采集。沉积物粒度谱采用Sympatec Helos KF Magic型激光粒度分析仪测定，其测量量程为0.5/18-3500 µm。测定前，样本经过氧化氢与乙酸分别处理，以氧化有机质组分并溶解碳酸盐颗粒。测定过程中，以十水合焦磷酸四钠作为分散剂，将样本悬浮于水中。粒度统计参数通过Gradistat软件（Blott与Pye，2001）计算，其基于应用于度量标尺的福克-沃德图解法（Folk与Ward，1957），详细公式与原理可参见Blott和Pye 2001年的相关研究。