Elsevier

Geomorphology

Volume 388, 1 September 2021, 107781
Geomorphology

Penultimate Glacial Cycle glacier extent in the Iberian Peninsula: New evidence from the Serra da Estrela (Central System, Portugal)

https://doi.org/10.1016/j.geomorph.2021.107781Get rights and content
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Highlights

  • Clear evidence of glacial extent at the end of the Penultimate Glacial Cycle (Marine Isotope 6) at c. 140 ka BP is presented.

  • The Last Glacial maximum ice extent occurred at c. 30 ka, at a site very close to the Penultimate Glacial Cycle maximum.

  • Data suggests that at c. 14.2 ka the Estrela plateau ice field had already disappeared.

  • Maximum ice extent at MIS6 is a significant result in the context of Iberia and for the understanding of the glacial history of SW Europe.

Abstract

The objective of this work is to present a first assessment on the age of the glacial features of the Serra da Estrela, in the central Portugal, Iberian Peninsula (40°19′ N, 7°37′ W, 1993 m), using Cosmic-Ray Exposure dating (in situ cosmogenic 36Cl). A total of 6 samples were dated, 4 extracted from exposed moraine boulders and 2 from glacially polished bedrock surfaces. Despite the low number of samples, the results are consistent, reinforcing previous dating obtained by other methods and geomorphological and paleoclimatic information. The maximum extension of the glaciers occurred at the end of the Penultimate Glacial Cycle (Marine Isotope Stage 6), during Heinrich Stadial 11, around 140 ka. At the end of the Last Glacial Cycle, slightly before the Last Glacial Maximum, at around 30 ka, the Estrela glaciers reached again a similar extent. Finally, the glaciers disappeared from the Serra da Estrela at the beginning of the Bølling-Allerød Interstadial, at around 14.2 ka. These data confirm a certain synchronicity in the major glacial phases in most the Mediterranean and also European mountains, although there are notable differences in the maximum extent in the two cycles.

Keywords

Penultimate Glacial Cycle
Last Glacial Cycle
Deglaciation
36Cl cosmogenic isotope
Serra da Estrela
Portugal

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