Sediment sample physical properties and biofacies abundance data (Excel format) for the CORE-VTRCC cruise (2021)

This data set presents sediment sample data consisting of biofacies abundance and sediment grain size and properties for samples collected in 2021 over the Vitoria Trindade Ridge during research cruise CORE-VTRCC on naval vessel Nho Cruzeiro do Sul. During the sampling program, nine seafloor sediment samples were collected within the Vitória-Trindade Ridge with a Van-Veen grab sampler (3600 cm²) on the top of the volcanic seamounts. Sample V7 collected only rhodoliths, without additional sediments. Grain sizes larger than 40 mm diameter (pebble size) were separated for rhodolith measurements. Sediment samples were washed to dissolve the salt concentration for 48 hours, then oven-dried at 45 °C for 72 hours. The rhodolith samples were dried at 35 °C for 48 hours. The morphometry of the rhodoliths was classified in spheirodal, discoidal and ellipsoidal based on the measurement of the long (L), intermediate (I) and short (S) axis with a Vernier Caliper. Samples were weighed and sieved in phi fractions (-1.5, -1.0, -0.5, 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 and > 4.0) for 10 minutes. Samples sieved were described in phi fractions and were grouped in the following orders: granules (-2 to -1), very coarse sand (-1 to 0), coarse sand (0 to 1), medium sand (1 to 2), fine sand (2 to 3), very fine sand (3 to 4) and silt (> 4). The mean grain size and sorting were analyzed on Gradistat v9.1 software. Sediment samples were also placed on a Petri dish for microscope analysis and photography using Fiji software. Grains were then classified (Carbonate debris, foraminifers, bryozoans, sponge spicules, bivalves, gastropods, crustaceans, echinoderms, and annelida) and abundance was quantified based on 300 random point counts per sample. The data file is in Excel spreadsheet format. In the file names, SS = "Seafloor Samples". For the analysis, each seafloor sample was subdivided into ten subsamples (Q number). Codes: V# - Number of Sample (_# goes when there is multiple images for the same sample); Q# - Number of the quartile sample (only for the biofacies). Funding for this work was provided through FAPESP awards 2016/24946-9 and 2020/08847-6, and through the Brazilian Navy program PROAMAZONIA AZUL.