27. Data Report: Grain-size Analysis of Sediments

Ocean Drilling Program (ODP) Leg 156 examined hydrological, geochemical, structural, and sedimentological processes at the toe of the northern Barbados accretionary prism (Shipley, Ogawa, Blum, et al., 1995). As part of this program, more than 400 samples were collected from Sites 948 and 949 for grain-size analysis. The primary objective of these analyses was to accurately determine weight percentages of sand, silt, and clay, to provide textural information that could be correlated with other types of data analyses made on immediately adjacent samples. The sediments collected during Leg 156 were dominantly finegrained clays and silts, with minor sands in lithologic Unit III below the décollement (Shipley, Ogawa, Blum, et al., 1995). In this study, we used the well-established size boundaries of 63 μm separating sand and silt, and 4 μm separating silt and clay.