Humid periods over western Sahara during the Middle Miocene Climate Transition and their implications on the carbon cycle

The Middle Miocene expansion of the Antarctic Ice Sheet coincides with major sedimentological changes in Malta. This interval also saw reorganisations in ocean circulation linked to closure of the Mesopotamian Seaway (MSR-events) and perturbations in the carbon cycle (CM events). The final CM event (CM-6), slightly lags the main glacial phase and remains difficult to interpret due to competing mechanisms and conflicting p CO 2 reconstructions. To explore links between cryosphere, circulation, hydroclimate, and the carbon cycle, we present new geochemical records from Malta. Our records show that cryospheric expansion was followed by large, precessionally paced variations in sea-surface salinity and a marked regional increase in biological productivity. The results indicate a shift toward stronger monsoonal influence, delivering enhanced freshwater and nutrient fluxes to the region. This enhanced local biological carbon pump may have acted as a positive feedback to a global CO 2 drawdown. However, any contribution to global CO 2 drawdown remains tentative and cannot be confirmed without contemporaneous high-resolution open-ocean records.