Quaternary marine and continental paleoenvironments in the western Mediterranean (Site 976, Alboran Sea): palynological evidence

Abstract

A continuous record of both marine and continental paleoenvironments in the Western Mediterranean has been investigated on the same samples from the composite core of Ocean Drilling Project (ODP) Leg 161, Site 976. Palynological analyses (pollen, dinoflagellate cysts, and organic matter) document the continental and marine paleoenvironmental changes in the Alboran Sea Basin from the beginning of the Pleistocene to the Holocene. The marine and continental records have been correlated to climate and/or hydrological changes. The pollen record depicts the vegetation changes in southern Spain and in North Africa along the Pleistocene and Holocene. Variability in abundant and diversified dinoflagellate cyst assemblages permits us to identify climatic and hydrological variations of surface waters along the whole sequence. During the upper Pleistocene, eight climatic cycles are evidenced both in marine and continental paleoenvironments and correlated to the δ18O curve. Focus on the last 28 calendar ka (cal ka) exhibits the major climatic events of the last climatic cycle: Last Glacial Maximum, Oldest Dryas, Bolling/Allerod, Younger Dryas, and Holocene. Periods of enhanced productivity are evidenced between 19 and 17 cal ka and during the Younger Dryas.