Evaluating sediment color as a paleoceanographic proxy in Santos Basin continental slope sediments, SW Atlantic

Abstract Sediment color is a valuable proxy in paleoceanography, reflecting chemical and mineralogical composition influenced by biogeochemical processes and depositional environments. This study investigates the relationship between sediment color (RGB and CIE L*a*b*) and metals in three radiocarbon-dated sediment cores from the Santos Basin continental slope (SW Atlantic). The cores, located within the Upper Circumpolar Water domain, span different time intervals. Results show significant color variation, especially after the Bølling–Allerød event. Although we identified statistical correlations between metals and color parameters (e.g., positive for Ca, negative for Ti), multiple regression analyses indicated that, among the major constituents of these sediments, calcium content was the strongest statistical predictor of color variability across the cores. The statistical association between metals and color was not consistently robust, particularly with significant changes before and after the Bølling-Allerød transition, possibly due to early diagenetic processes. We argue that the relationship between sediment color and composition in samples from the Santos Basin is more complex than simple correlation coefficients, as observed at other continental margins.