Reversible glacial-periglacial transition in response to climate changes and paraglacial dynamics: A case study from Héðinsdalsjökull (northern Iceland)

David Palacios*, Manuel Rodríguez-Mena, José M. Fernández-Fernández, Irene Schimmelpfennig, Luis M. Tanarro, José J. Zamorano, Nuria Andrés, Jose Úbeda, Þorsteinn Sæmundsson, Skafti Brynjólfsson, Marc Oliva, A. S.T.E.R. Team

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The objective of this work is to chronologically establish the origin of the different glacial and rock glacier complex landforms deposited by Héðinsdalsjökull glacier (65°39′ N, 18°55′ W), in the Héðinsdalur valley (Skagafjörður fjord, Tröllaskagi peninsula, central northern Iceland). Multiple methods were applied: geomorphological analysis and mapping, glacier reconstruction and equilibrium-line altitude calculation, Cosmic-Ray Exposure dating (in situ cosmogenic 36Cl), and lichenometric dating. The results reveal that a debris-free glacier receded around 6.6 ± 0.6 ka, during the Holocene Thermal Maximum. The retreat of the glacier exposed its headwall and accelerated paraglacial dynamics. As a result, the glacier terminus evolved into a debris-covered glacier and a rock glacier at a slightly higher elevation. The front of this rock glacier stabilized shortly after it formed, although nuclide inheritance is possible, but its sector close the valley head stabilized between 1.5 and 0.6 ka. The lowest part of the debris-covered glacier (between 600 and 820 m altitude) collapsed at ca. 2.4 ka. Since then, periods of glacial advance and retreat have alternated, particularly during the Little Ice Age. The maximum advance during this phase occurred in the 15th to 17th centuries with subsequent re-advances, namely at the beginning of the 19th and 20th centuries. After a significant retreat during the first decades of the 20th century, the glacier advanced in the 1960s to 1990s, and then retreated again, in accordance with the local climatic evolution. The internal ice of both the debris-covered and the rock glacier have survived until the present day, although enhanced subsidence provides evidence of their gradual degradation. A new rock glacier developed from an ice-cored moraine from around 1940–1950 CE. Thus, the Holocene coupling between paraglacial and climatic shifts has resulted in a complex evolution of Héðinsdalsjökull, which is conflicting with previously proposed models: a glacier, which had first evolved into a debris-covered and rock glacier, could later be transformed into a debris-free glacier, with a higher sensitivity to climatic variability.

Original languageEnglish
Article number107787
JournalGeomorphology
Volume388
DOIs
Publication statusPublished - 1 Sep 2021

Bibliographical note

Funding Information:
This paper was funded by PR108/20-20 (Santander Bank-UCM Projects) and Nils Mobility Program (EEA GRANTS), and with the help of the High Mountain Physical Geography Research Group (Universidad Complutense de Madrid). We thank the Icelandic Association for Search and Rescue, the Icelandic Institute of Natural History, the H?lar University College, David Palacios Jr. and Mar?a Palacios for their support in the field. Jos? M. Fern?ndez-Fern?ndez is supported by a postdoctoral grant within the NUNANTAR project (02/SAICT/2017 32002; Funda??o para a Ci?ncia e a Tecnologia, Portugal). Marc Oliva is supported by the Ram?n y Cajal Program (RYC-2015-17597) and by the Research Group ANTALP (Antarctic, Arctic, Alpine Environments; 2017-SGR-1102) funded by the Government of Catalonia. The 36Cl measurements were performed at the ASTER AMS national facility (CEREGE, Aix en Provence), which is supported by the INSU/CNRS and the ANR through the ?Projets th?matiques d'excellence? program for the ?Equipements d'excellence? ASTER-CEREGE action and IRD. The authors are grateful for the comments and suggestions of Dr. Jasper Knight and anonymous reviewer, which have considerably improved the quality of the manuscript.

Funding Information:
This paper was funded by PR108/20-20 ( Santander Bank-UCM Projects ) and Nils Mobility Program ( EEA GRANTS ), and with the help of the High Mountain Physical Geography Research Group (Universidad Complutense de Madrid). We thank the Icelandic Association for Search and Rescue, the Icelandic Institute of Natural History, the Hólar University College, David Palacios Jr. and María Palacios for their support in the field. José M. Fernández-Fernández is supported by a postdoctoral grant within the NUNANTAR project ( 02/SAICT/2017 32002 ; Fundação para a Ciência e a Tecnologia , Portugal). Marc Oliva is supported by the Ramón y Cajal Program ( RYC-2015-17597 ) and by the Research Group ANTALP (Antarctic, Arctic, Alpine Environments; 2017-SGR-1102 ) funded by the Government of Catalonia . The 36 Cl measurements were performed at the ASTER AMS national facility (CEREGE, Aix en Provence), which is supported by the INSU/CNRS and the ANR through the “Projets thématiques d'excellence” program for the “Equipements d'excellence” ASTER-CEREGE action and IRD. The authors are grateful for the comments and suggestions of Dr. Jasper Knight and anonymous reviewer, which have considerably improved the quality of the manuscript.

Publisher Copyright:
© 2021 The Authors

Other keywords

  • Climatic variability
  • Debris-covered glacier
  • Debris-free glacier
  • Glacial evolution
  • Northern Iceland
  • Paraglacial dynamics
  • Rock glacier

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