Holocene climatic and environmental evolution on the southwestern Iberian Peninsula: A high-resolution multi-proxy study from Lake Medina (Cádiz, SW Spain).

Abstract

The climatic and environmental history of the SW Iberian Peninsula is explored tofill in the gap ofcontinental palaeoclimate data by a high-resolution study of Lake Medina sediments from core Co1313. Amulti-proxy approach comprising sedimentary facies analysis, elemental geochemistry, mineralogy,palynology and micropaleontology was employed to reconstruct the complex limnological response toclimate change and catchment dynamics since the early Holocene. The further definition of abruptclimate change events was supported by a robust age model and rapid sediment accumulation rate at thestudy site. Proxies indicate arid and warm climate conditions during the Early Holocene, from around 9.5to 7.8 cal ka BP, with a desiccation event at 8.8 cal ka BP as well as tentative evidence for the regionalexpression of a cold and abrupt arid climate event centering on ca. 8.2 cal ka BP. The Holocene ClimateOptimum, from around 7.8 to 5.5 cal ka BP, is characterized by a humid climate and maximum lake level.Anoxic bottom water conditions are indicated by the preservation of sediment laminae and the occur-rences of Sulfur mottles, which were observed for thefirst time within Holocene sediments of salinelakes. Mid-to Late Holocene times are governed by the 4.2 cal ka BP dry event as well as progressivearidification accompanied by the development of typical Mediterranean low-land vegetation. Duringrecent times, further progressive loss in precipitation as well asfluctuating but overall increasinganthropogenic influence on Lake Medina sediments is observed