Sortable silt of sediment cores GC-01A from Gulf of Cadiz

For sortable-silt 83 samples were analysed in the fraction <63 micron. In these, organic matter was eliminated with 33% of hydrogen peroxide (H2O2) and carbonates removed with 0.2N hydrogen chloride (HCl). Then, samples were dispersed with 0.5% Na-hexametaphosphate (Calgon) and ultra-sonicated for 2 minutes. Prior to grain-size analysis in a Sedigraph Micromeritics III Plus, samples were homogenised by stirring in a magnetic plate for 30 minutes. The grain-size distribution was acquired in the interval 10-63 micron, assumed to have non-cohesive behaviour during transport and deposition (McCave et al., 1995), at the IGME. The sortable silt mean of the carbonate-free 10-63 micron interval is designated as SS (McCave et al., 1995). The percentage of sortable silt (SS%), i.e. % (10-63 micron)/<63 micron, is also a key parameter obtained from Sedigraph analyses. Dry-density required for the grain size distribution calculation was measured by using a pycnometer Micromeritics Accupy 1330.

针对可分选粉砂（sortable-silt），对<63微米粒级的83个样品进行了分析。在这些样品中，使用33%的过氧化氢（H₂O₂）去除有机质，并用0.2N的盐酸（HCl）去除碳酸盐。随后，使用0.5%的六偏磷酸钠（Na-hexametaphosphate，Calgon）分散样品，并超声处理2分钟。在使用Sedigraph Micromeritics III Plus进行粒度分析前，样品在磁力搅拌板上搅拌30分钟以均质化。粒度分布在10-63微米区间内获取，该区间被认为在搬运和沉积过程中具有非黏聚性（McCave等，1995），分析在IGME进行。无碳酸盐的10-63微米区间内的可分选粉砂均值被定义为SS（McCave等，1995）。可分选粉砂的百分比（SS%），即%（10-63微米）/<63微米，也是从Sedigraph分析中获得的关键参数。粒度分布计算所需的干密度通过使用Micromeritics Accupy 1330比重瓶进行测量。