Did Pyrenean glaciers dance to the beat of global climatic events? Evidence from the Würmian sequence stratigraphy of an ice-dammed palaeolake depocentre in Andorra
Published:January 01, 2017
Valentí Turu, Marc Calvet, Jaume Bordonau, Yanni Gunnell, Magali Delmas, Joan Manuel Vilaplana, Guy Jalut, 2017. "Did Pyrenean glaciers dance to the beat of global climatic events? Evidence from the Würmian sequence stratigraphy of an ice-dammed palaeolake depocentre in Andorra", Quaternary Glaciation in the Mediterranean Mountains, P. D. Hughes, J. C. Woodward
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The ice-marginal depositional sequence of La Massana provides a chronostratigraphic benchmark for reconstructing the Würmian glacial evolution of the Valira catchment in Andorra, SE Pyrenees. The sedimentary record of Andorra confirms the asynchronous chronology of glacier fluctuations in different parts of the Pyrenean mountain range. A major ice recession occurred at the end of Marine Isotope Stage (MIS) 4. High magnitude valley-glacier fluctuations during MIS 3 constitute another important finding. Major readvances occurred toward the end of MIS 3, whereas MIS 2 (in particular, the global Last Glacial Maximum, or LGM) featured sharp contrasts in ice recession rates between Pyrenean valleys. Substantial distances separated MIS 4 glacier fronts (the Würmian maximum ice extent, or MIE) from those reached during the global LGM, in contrast to situations in the eastern Pyrenees, where Würmian MIE and global LGM ice fronts nearly coincided. Overall, the Valira glaciers reveal patterns that are more similar to those recorded elsewhere in the western and central Pyrenees than in the eastern Pyrenees. The rapid fluctuations recorded by Andorran glaciers during the second half of the Würm also suggest a response to global forcing events such as Heinrich events in the North Atlantic.
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Quaternary Glaciation in the Mediterranean Mountains
The mountains of the Mediterranean world are now largely ice free, but many were repeatedly glaciated during the Quaternary ice age. This created spectacular glaciated landscapes with a rich array of glacial deposits and landforms. The glacial and glacio-fluvial records are often very well preserved and our understanding of the timing of Quaternary glaciation has very recently been transformed through the application of dating methods utilizing uranium-series and cosmogenic isotopes. Glacial records from the Mediterranean now boast some of the most robust chronologies for mountain glaciation anywhere in the world – they represent a unique archive of Quaternary environmental change of global significance. The southerly latitude and relatively small size of Mediterranean glaciers rendered them especially sensitive to Pleistocene and Holocene climate changes. This volume brings together the leading researchers and the latest research on Mediterranean glaciation. Several papers also explore glacier behaviour in the Holocene – including those glaciers of southernmost Europe at risk of disappearing this century.