Climate and vegetation changes in coastal ecosystems during the Middle Pleniglacial and the early Holocene: Two multi-proxy, high-resolution records from Ría de Vigo (NW Iberia)

Abstract New multi-proxy analyses were performed on two sedimentary sections from shallow marine ecosystems of Ria de Vigo (NW Iberia) to study the effects of the MIS-3 and early Holocene environmental variability. High-resolution data (microfossils, sedimentary facies, and geochemistry) allowed performing a comprehensive reconstruction of the main environmental changes (climate, vegetation, hydrology and sea level) that occurred during part of the MIS-3 period (57.0–38.8 cal ka BP) and the early Holocene (11.2–7.0 cal ka BP). The chronology is supported by isotopic dating and the correlation of pollen data with other regional palaeo-climatic records. Several phases characterised by increasing pollen representation of deciduous Quercus alternate with others marked by increasing representation of heliophytes that may reflect the succession of Interstadials (GI) and Stadials (GS) described in Greenland ice cores. In addition, dinoflagellate cysts and diatoms reflect conditions in the marine environment (SST and productivity). New palynological data confirms that coastal ecosystems of Atlantic Iberia were sensitive to the main climatic oscillations affecting the North Atlantic. It also suggests that pinewoods, juniper communities and mesophilous deciduous forests with Carpinus betulus L. (which shows exceptionally high pollen abundances for the MIS-3) persisted in the surroundings of Ria de Vigo until ~7500 a BP. For the first time in this region, we describe the effects of an abrupt episode of cooling that may correspond to Bond cycle 7 (10.5 ka event).