Palaeoclimatological research of the Early Quaternary from the Laguna de Medina, Cádiz, Spain

Abstract

Our work (C3 project) is a contribution to the CRC 806 “Our way to Europe”, dealing with the climatic and environmental changes in the Upper Pleistocene – Middle Holocene of the Iberian Peninsula (IP) and its connection to human migration. The connection between archeological and geological archives is one of the aims of this research. The question of the Late Quaternary climate in the Western Mediterranean and its influence on human migration is still not, or more over contradictory answered. This is probably due to scarce investigable archives on the Southern Iberian Peninsula.
The climate had strong influence on the migration of early humans (Finlayson et al. 2006). (Bard 2013) stated, that transformations resulting out of increasing demographic pressure due to climate lead to the rise of civilizations like the Egyptian and the Mediterranean climate is one of the most sensitive to changes (Beklioglu et al. 2007). Short term climate changes like the Heinrich-events (HE), which lead to arid and cold conditions on the southern IP (Bout-Roumazeilles et al. 2007) (Bard et al. 2000), could have affected human populations even more because of the shorter time of adaption. Lakes constitute excellent climate archives (Cohen 2003) and in Southern Spain they are often endorheic, which makes them even more sensitive to changes of the climate (Corella et al. 2011). Lacustrine deposits of Holocene age on the IP were investigated, but most of these archives lack a sub millennial resolution (Corella et al. 2011).
In this study, the lacustrine deposit of the Laguna de Medina, the second largest inland salt lake of Andalusia (De Vicente et al. 2012), is investigated. In September 2014 two sediment cores with a total length of 21,34 m were drilled with the use of a platform (N36°37´04,380 /W06°03´12,720; water depth 1,7 m). The cores were scanned by the MSCL every centimetre for magnetic susceptibility and by the XRF-scanner for elements (every 0.2 cm) and radiographic photos (every 0.02 cm). Samples of 2 cm were taken every 6 cm for grain size analyses, TIC/TOC, CNS, ostracods, diatoms and plant remains and every 24 cm for pollen analyses.
The Laguna de Medina contains a more or less continuous record of past conditions. After (Reed et al. 2001), these lake sediments demonstrate high variations of water depth and salinity, at least of the last 8700 years. Moreover, the lake shows a trend of perennial conditions in earlier times to ephemeral conditions, closely linked to climate. Our preliminary results show a high resolution signal of probably the last 20 000 years, which will lead to a much better understanding of the relation between climate and human migration on the IP because of our multi-proxy approach and a close interfingering with archaeologists working in the nearest archaeological sites.

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Corella, J.P. et al., 2011. Climate and human impact on a meromictic lake during the last 6,000 years (Montcortès Lake, Central Pyrenees, Spain). Journal of Paleolimnology, 46(3), pp.351–367.
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Bibliography

van ´t Hoff, J., Schröder, T., Melles, M., Reicherter, K. (2015): Palaeoclimatological research of the Early Quaternary from the Laguna de Medina, Cádiz, Spain. Proc. of the meeting on Progress in Quaternary Archive Studies in the Iberian Peninsula