Organic carbon burial in Mediterranean sapropels intensified during Green Sahara Periods since 3.2 Myr ago

Abstract Dark organic-rich layers (sapropels) have accumulated in Mediterranean sediments since the Miocene due to deep-sea dysoxia and enhanced carbon burial at times of intensified North African run-off during Green Sahara Periods (GSPs). The existence orbital precession-dominated Saharan aridity/humidity cycles is well known, but lack long-term, high-resolution records hinders understanding their relationship with environmental evolution. Here we present continuous, geochemical magnetic for Eastern spanning past 5.2 million years, which reveal that organic 3.2 Myr ago. We deduce fluvial terrigenous sediment inputs GSPs doubled abruptly this time, whereas monsoon intensity remained relatively constant. hypothesize increased mobilization resulted from an abrupt non-linear landscape response associated a major increase arid:humid contrasts between intervening dry periods. timing strongly suggests link onset northern hemisphere glaciation.