Climatic and Environmental Changes in the Upper Pleistocene – Middle Holocene of the Iberian Peninsula

Principal Investigators: H. Brückner, K. Reicherter, M. Melles

During the 2nd Phase of the CRC, the new project C3 will start its work on possible relationships between climatic and environmental changes during the Upper Pleistocene to Middle Holocene in the Iberian Peninsula (IP), based on long-term and preferably continuous archives such as lake and lagoonal deposits. During the 1st Phase of the CRC, these off-site investigations were partly carried out in the frame of the C1 project; however, it turned out that the number of potential sites is larger than originally expected and the workload for high-resolution multi-proxy analyses is so high that, it justifies a stand-alone project in the frame of the C-Cluster.

Generally, cave and alluvial sediments lack continuous information due to environmental changes and preservation conditions. Therefore, we will focus on cores from mainly persistent archives to cover the time intervals considered in projects C1 and C2. In Northern Iberia a good record of continuous archives has been established compared to Southern Iberia. Southern Spain and Portugal are no typical lake countries, but we identified and tested several promising archives during the 1st Phase of project C1, broadly north of the 40th parallel, as also shown by vegetation studies.

Project C3 aims towards filling the regional gap in Late Quaternary palaeoclimate archives on the western IP that exists between marine records from the Atlantic off Portugal (ODP Leg 149; plus e.g. IMAGES core MD95-2042) and from the Sea of Alborán (Leg 161; plus e.g. IMAGES core MD95-2043) on the one hand, and terrestrial records on the IP, e.g. the Padul peat bog near Granada city, on the other. The distance between theses archives is up to 600 km, crossing the climatic zones of the humid Atlantic IP (Portugal and Galicia) and the dry Mediterranean IP (Extremadura and Andalusia). Both, the Atlantic IP and the Mediterranean IP, were inhabited by neanderthals and anatomically moderns humans and subjected to a direct climatic influence of the North Atlantic Oscillation (NAO), including short-term climate changes such as the Heinrich Events (HE) or the Dansgard/Oeschger Events (DO events).

Our investigations of sedimentary archives in the western IP have a temporal focus on MIS 3 to MIS 2, or on the four main techno complexes Late Middle Palaeolithic to Early Upper Palaeolithic, Gravettian and Solutrean (in project C1), and Magdalenian (transition into MIS 1). Special emphasis is put on short-term HE and DO events, the rapid environmental changes that may have forced reactions of hunter gatherer populations. Some of the archives tested in the first CRC phase turned out to be not really suitable for high-resolution studies, like the polje of Zafarraya in Jurassic limestone, where we carried out geophysical and geological investigations. More promising are archives like the ephemeral lakes of the Triassic gypsum karst (Keuper facies). These partly saline or freshwater lakes – confusingly called 'lagunas' in Spanish – yield long sedimentary sequences, which are currently under investigation (see chapter "Education"). Our envisaged sites are all geographically closely related to the cave and rock shelter sites investigated in project C1. They constitute small lakes or coastal lagoons (partly with a freshwater phase). In Portugal we also incorporated some caves, because stable isotope studies of speleothems are lacking and lake deposits are rare in this part of the IP.

Our laboratory work on the sediment sequences will comprise high-resolution sedimentological, geochemical, and geophysical analyses, including Multi-Sensor Core Logging, X-Ray Fluorescence (XRF) scanning, and organic geochemistry. The age models will be based on radiocarbon, luminescence, and palaeomagnetic dating, carried out in cooperation with projects F1, F5, and F6, respectively. In addition, stable isotope studies of carbonates, both from speleothems and lacustrine ones, will be done in cooperation with project B5. The palaeoenvironmental results will be extensively compared with the cultural changes on the IP, detected by project C1 and with data on man environment relationship from Morocco generated by project C2. Similarities of the palaeoenvironmental development in Southern Iberia and Morocco are obvious.

 

 

 

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