Chronological and geomorphological investigation of fossil debris-covered glaciers in relation to deglaciation processes: A case study in the Sierra de La Demanda, northern Spain

  1. Aumaître, G. 1
  2. Bourlès, D. 1
  3. Keddadouche, K. 1
  4. Schimmelpfennig, I. 1
  5. Léanni, L. 1
  6. Fernández-Fernández, J.M. 6
  7. Palacios, D. 6
  8. Andrés, N. 6
  9. Úbeda, J. 6
  10. García-Ruiz, J.M. 5
  11. Gómez-Villar, A. 4
  12. Santos-González, J. 4
  13. Álvarez-Martínez, J. 3
  14. Arnáez, J. 2
  1. 1 Aix-Marseille University
    info

    Aix-Marseille University

    Marsella, Francia

    ROR https://ror.org/035xkbk20

  2. 2 Universidad de La Rioja
    info

    Universidad de La Rioja

    Logroño, España

    ROR https://ror.org/0553yr311

  3. 3 Universidad de Valladolid
    info

    Universidad de Valladolid

    Valladolid, España

    ROR https://ror.org/01fvbaw18

  4. 4 Universidad de León
    info

    Universidad de León

    León, España

    ROR https://ror.org/02tzt0b78

  5. 5 Instituto Pirenaico de Ecología
    info

    Instituto Pirenaico de Ecología

    Zaragoza, España

    ROR https://ror.org/039ssy097

  6. 6 Universidad Complutense de Madrid
    info

    Universidad Complutense de Madrid

    Madrid, España

    ROR 02p0gd045

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Revista:
Quaternary Science Reviews

ISSN: 0277-3791

Any de publicació: 2017

Volum: 170

Pàgines: 232-249

Tipus: Article

DOI: 10.1016/J.QUASCIREV.2017.06.034 SCOPUS: 2-s2.0-85021929091 WoS: WOS:000407524000018 GOOGLE SCHOLAR

Altres publicacions en: Quaternary Science Reviews

Resum

In this study, fossil debris-covered glaciers are investigated and dated in the Sierra de la Demanda, northern Spain. They are located in glacial valleys of approximately 1 km in length, where several moraines represent distinct phases of the deglaciation period. Several boulders in the moraines and fossil debris-covered glaciers were selected for analysis of 10Be surface exposure dating. A minimum age of 17.8 ± 2.2 ka was obtained for the outermost moraine in the San Lorenzo cirque, and was attributed to the global Last Glacial Maximum (LGM) or earlier glacial stages, based on deglaciation dates determined in other mountain areas of northern Spain. The youngest moraines were dated to approximately 16.7 ± 1.4 ka, and hence correspond to the GS-2a stadial (Oldest Dryas). Given that the debris-covered glaciers fossilize intermediate moraines, it was deduced that they developed between the LGM and the Oldest Dryas, coinciding with a period of extensive deglaciation. During this deglaciation phase, the cirque headwalls likely discharged large quantities of boulders and blocks that covered the residual ice masses. The resulting debris-covered glaciers evolved slowly because the debris mantle preserved the ice core from rapid ablation, and consequently they remained active until the end of the Late Glacial or the beginning of the Holocene (for the San Lorenzo cirque) and the Holocene Thermal Maximum (for the Mencilla cirque). The north-facing part of the Mencilla cirque ensured longer preservation of the ice core. © 2017 Elsevier Ltd