Grain-size data from dry sieving and GRADISTAT analysis of inter-reef surface sediments, Spermonde Archipelago, SW Sulawesi, Indonesia

This dataset reports grain-size data for 51 sieved subsamples derived from inter-reef seafloor surface sediment samples from the Spermonde Archipelago, SW Sulawesi, Indonesia. Raw dry sieve weights (mg) are provided for eleven size fractions ranging from >16 mm to <63 µm, together with relative sieving error (%). Statistical grain-size parameters, including mean grain size, sorting, skewness, and kurtosis, were calculated using the Folk and Ward (1957) graphical method and the arithmetic, geometric, and logarithmic methods of moments as implemented in GRADISTAT v8 (Blott & Pye, 2001). Percentile values (D10, D50, D90), modal class(es), textural descriptions, and proportions of gravel, sand, and mud fractions are also reported. These data document the cross-shelf grain-size gradient and provide the sedimentological basis for facies classification. The field sampling was performed in August 2021 in the framework of the HAnsea project, sample depths range from 4.5 to 73.6 m water depth. Data collection was done between June 2023 and April 2024.