The data refer to the geochemical and isotopic characterization of microbial carbonate in the shallow platform of the South Atlantic Ocean, Espírito Santo - Brazil. The determination of 14C activity was performed in Accelerator Mass Spectrometry (AMS) 14C dating at the Poznań Radiocarbon Laboratory. The determination of 14C activity was performed on 06 samples in Accelerator Mass Spectrometry (AMS) 14C dating at the Poznań Radiocarbon Laboratory (Linick et al., 1989). Background corrections were applied based on measurements of 14C-free calcite. Radiocarbon ages were calculated using the conventional radiocarbon age method (Stuiver and Polach, 1977) and calibrated using the CALIB REV8.20 software (Stuiver and Reimer, 1993). Calibration curves from Cabo Frio (RJ) and Guarapari (ES) were employed, with Delta R values -40.0 ± 17 and 29 ± 53 (Heaton et al., 2020; Alves et al., 2021). All dated samples were assigned a standard deviation of ±30 to ±35 years (2σ).

The study was carried out between 2021 and 2023 on the beach of Castelhanos in a carbonate bank to analyze the depositional dynamics throughout the Holocene. The occurrence of microbial carbonates in the open marine environment is uncommon globally, configuring an excellent proxy for the reconstitution of relative variations in sea level and paleoclimate.