Here we present the data of a sequential extraction scheme, which aims to evaluate the effect of barite-bound Sr in the residual fraction after decarbonation. The investigation is done with pertinent examples for Mediterranean sediments, focusing on the most-recent sapropel S1 interval. A total of 130 samples were taken from 10 cores in the eastern Mediterranean Sea (EMS) and 1 core in the western Mediterranean Sea. This selection represents a geographic and bathymetric coverage of the EMS and permits the basin-wide comparison between organic-rich and -lean sediments. After decarbonation using 1 M HCl solution, the residual sediments were subject to NH4Cl extraction (2 M, pH 7), known to selectively dissolve barite. Our results demonstrate the presence of Sr-bearing barite after traditional carbonate removal and its effect on the derived “detrital” Sr signature, with important implications for detrital provenance studies.