Abstract
Cirques are glacially eroded, bowl-shaped depressions, characterised by steep headwalls and flat or over deepened floors. Given their association with past glaciers, cirques are sometimes used as proxies for palaeoclimate. However, cirques are shaped over multiple glacial cycles, and their usefulness as palaeoclimate indicators therefore remains open to question. In this paper, we map 3984 glacier-free cirques across the Scandinavian Peninsula and analyse variations in cirque floor altitude (CFA). We explore the relationships between CFAs and cirque aspect, latitude, longitude, and distance to the coast. We test the validity of using CFAs as indicators of palaeoclimate through comparison with the equilibrium-line altitudes (ELAs) of 513 modern cirque glaciers. Results
indicate that both CFAs and modern cirque-glacier ELAs decrease with latitude and vary with aspect, being generally lowest on east-facing slopes. However, the clearest and strongest trend in both CFAs and modern cirque glacier ELAs is an increase in elevation with distance from the modern coast (i.e., distance ‘inland’). This likely indicates that similar climatic gradients, particularly an inland reduction in precipitation, acted to regulate former sites of glacier initiation (reflected by CFAs) and modern glacier ELAs. This would imply that CFAs are a useful proxy for palaeoclimate. However, we note that both CFAs and modern ELAs reflect the general topography of this region (with increasing elevations moving inland), and the glacial history of the area (indirectly linked to palaeoclimate) may have played a role in regulating where cirques have formed. For these reasons, we suggest that palaeoclimatic interpretations derived from CFAs should be treated with caution.
indicate that both CFAs and modern cirque-glacier ELAs decrease with latitude and vary with aspect, being generally lowest on east-facing slopes. However, the clearest and strongest trend in both CFAs and modern cirque glacier ELAs is an increase in elevation with distance from the modern coast (i.e., distance ‘inland’). This likely indicates that similar climatic gradients, particularly an inland reduction in precipitation, acted to regulate former sites of glacier initiation (reflected by CFAs) and modern glacier ELAs. This would imply that CFAs are a useful proxy for palaeoclimate. However, we note that both CFAs and modern ELAs reflect the general topography of this region (with increasing elevations moving inland), and the glacial history of the area (indirectly linked to palaeoclimate) may have played a role in regulating where cirques have formed. For these reasons, we suggest that palaeoclimatic interpretations derived from CFAs should be treated with caution.
Original language | English |
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Article number | 111062 |
Number of pages | 12 |
Journal | Palaeogeography Palaeoclimatology Palaeoecology |
Volume | 600 |
Early online date | 26 May 2022 |
DOIs | |
Publication status | Published - 15 Aug 2022 |
Bibliographical note
ACKNOWLEDGEMENTSThe Scottish Alliance for Geoscience Environment and Society (SAGES) and the University of Aberdeen are thanked for funding the PhD studentship awarded to Rachel P. Oien. I am grateful for the data provided by various scientists at the NVE and NGU in order to make this project possible. We thank Ian Evans, and an anonymous reviewer for their extremely helpful corrections,comments, and suggestions.
Keywords
- ELA
- Cirques
- Palaeoclimate
- Climate
- Glacier