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Late Pleistocene Paleoclimate Records from Two Portuguese Caves

Authors: Mike Benedetti*, University Of North Carolina Wilmington, Jonathan A. Haws, University of Louisville, Rhawn F. Denniston, Cornell College
Topics: Paleoenvironmental Change, Geomorphology, Physical Geography
Keywords: Paleoenvironments, Caves, Europe
Session Type: Poster
Presentation File: No File Uploaded


The Maciço Calcário Estremenho limestone province in west-central Portugal contains many well-known caves and rockshelters. Paleoclimate proxies from offshore deep-sea sediment cores indicate large environmental responses to Pleistocene climate change in this region. These include rapid changes in sea surface temperature, upwelling intensity, vegetation, and fire frequency during stadial-interstadial transitions. The most severe cold/arid conditions occurred during iceberg rafting events known as Heinrich stadials (HS).

This poster presents data from two caves that illustrate fluctuations in Late Pleistocene hydrology and weathering intensity in the region:

1) Lapa do Picareiro is a large cave where archaeological excavations have revealed more than 10 m of sedimentary fill dating to 9-75 ka, containing abundant faunal and archaeological evidence. Sedimentological parameters, especially éboulis clast size and magnetic susceptibility (MS), show good agreement with paleoclimate records back to at least 45 ka. Cold/arid HS are represented by prominent coarse clast beds with little fine sediment and MS minima, while milder interstadials correspond with muddy beds and abrupt MS peaks.

2) Stalagmites from Buraca Gloriosa contain a record of effective soil moisture based on growth curves and isotope ratios (δ13C, δ18O, and δ234U) overlapping with the period of record at Picareiro. The speleothem record is broadly consistent with the MS signal from Picareiro and other regional proxies. Cold/arid HS are marked by hiatuses in stalagmite growth, or strong isotopic excursions representing strongly reduced soil moisture.

These results illustrate the terrestrial impacts of Pleistocene climate change and provide context for archaeological studies in the region.

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