Surface sediment grain-size characteristics of the Bohai, Yellow, and East China seas: a comprehensive survey based on unified laser diffraction analysis

<jats:p>Abstract. This paper presents a comprehensive grain-size dataset comprising 751 surface sediment samples collected from the Bohai Sea, Yellow Sea, and East China Sea—the three major continental shelf seas of China. Samples were obtained over an extended period from 2001 to 2019 using box samplers in accordance with the national marine survey standard (GB/T 12763.8–2007). All samples were analyzed by a Malvern Mastersizer 2000 laser diffraction particle size analyzer following hydrogen peroxide pretreatment for organic matter removal. The dataset provides the full grain-size distribution at 0.25 Φ intervals from −0.75 Φ to &gt;10 Φ. The instrument measures directly in micrometres (0.02–2000 μm); we provide two companion data files — one in Φ (phi) scale and one in micrometres (μm) — to accommodate both sedimentological convention and direct instrumental units. The dataset also includes derived Folk–Ward statistical parameters including mean grain size (Mz), sorting coefficient (σi), skewness (Ski), and kurtosis (Kg). Ternary fractions of sand (−1 to 4 Φ), silt (4 to 8 Φ), and clay (&gt;8 Φ) are also included. Across the dataset, sand content ranges from 0 to 100 % (mean 40.1 %), silt from 0 to 76.8 % (mean 41.3 %), and clay from 0 to 50.3 % (mean 18.6 %). Mean grain size (Mz) ranges from 1.51 to 8.13 Φ (mean 5.26 Φ, corresponding to approximately 26 μm). The dataset is expected to support research on sediment dynamics, paleoenvironmental reconstruction, benthic habitat mapping, and marine engineering across the Chinese continental margin. All data are archived in an open-access repository with a CC BY 4.0 license.</jats:p>