Vegetation and climate dynamics in the south-western mediterranean during MIS 37–31 (∼1.25 - ∼1. 06 Ma): Insights from the marine core ODP site 976

Abstract

The Early to Middle Pleistocene Transition (EMPT; 1.4 to 0.4 Ma) represents a major change in the Earth's climate, marked by a shift from obliquity-driven glacial cycles of 41,000 years to dominant cycles of 100,000 years. This period is crucial for understanding climate and vegetation change, as it marks the final phase of the disappearance of megatherm and mesotherm forest taxa that had been present in Europe since the Miocene and Pliocene period. However, sedimentary records from this period are sparse, particularly in the Mediterranean region. Here, we present continuous pollen and isotopic records spanning Marine Isotope Stages (MIS) 37–31 (∼1.25–1.06 Ma) from site ODP 976 in the Alboran Sea, the first continuous sequence in the Western Mediterranean for this period, which is discussed in light of a corpus of records to reflect the broader dynamics of the Mediterranean vegetation. Pollen data show similar successions around the Mediterranean: steppe vegetation during glacial periods, temperate forests during interglacial periods, and the development of conifers during transition phases, reflecting the gradual shift from 41 ka to 100 ka cycles. Differences in the vegetation composition between the west and the rest of the Mediterranean during Interglacial-Glacial/Glacial-Interglacial transitions are highlighted by the important role of Cupressaceae and Ericaceae. It clearly indicates the scarcity of relict taxa (Sciadopitys, Cathaya, Eucommia) south of 40°N, revealing a north-south gradient of decline associated with increasing aridity and challenging the traditional view of "southern refugia."