Carbonate sediments on continental slopes in temperate areas have not received as much attention as their tropical counterparts. This study documents the sedimentology and main early diagenetic features of hemipelagic carbonate oozes from two piston cores from the continental slope of the south Balearic margin (western Mediterranean) between 38° and 39°N. The two cores contain hemipelagic carbonate oozes consisting of a mixture of clay minerals and several carbonate phases, which settled on the flanks of the Balearic carbonate platform during the last full Quaternary glacial-interglacial cycle. Textural, faunal and mineralogical data suggest that the Balearic sedimentary record is closely related to changes in productivity, dissolution and dilution, all of which are related to δ18O and δ13C signals during the Late Quaternary. The dominant carbonate phase is low-magnesian calcite, whereas aragonite and high-magnesian calcite are present as minor components. The incorporation of low-magnesian calcite in the sediment is due to planktonic pelagic rain. The high-magnesian calcite is incorporated via resuspension of particles originating from the degradation of molluscan and red algal carbonate skeletons from the adjacent carbonate-rich Balearic shelves. Aragonite derives from pteropods and presumably shallow-water aragonite organisms, as the red algae Peyssonelia. The main differences between tropical carbonate slope sediments and Balearic temperate hemipelagic oozes are the lesser amounts of carbonate minerals, mainly aragonite and high-magnesian calcite, and the greater quantity of quartz and clay minerals. Our results suggest that the hemipelagic carbonate oozes of the Balearic slope are an intermediate type of carbonate oozes between the low-magnesian calcite deep-pelagic oozes with low diagenetic potential and the multiphasal carbonate tropical periplatform sediments with high diagenetic potential.

Peer Reviewed