Climatic controls on the equilibrium-line altitudes of Scandinavian cirque glaciers

Oien, Rachel P.; Spagnolo, Matteo; Rea, Brice R.; Barr, Iestyn D.; Bingham, Robert G.

doi:10.1016/j.geomorph.2019.106986

Cited by 13 publications

(19 citation statements)

References 51 publications

(54 reference statements)

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“…2019; Oien et al . 2020). A trend of higher precipitation values on the eastern side of the islands compared to the west, similar to the one seen at present (Table 1), may have influenced the formation of cirque glaciers over time.…”

Section: Discussionmentioning

confidence: 99%

“…2019) or to the fact that the larger landmass size provides more topographic availability for cirques to form (Oien et al . 2020).…”

Section: Discussionmentioning

confidence: 99%

“…However, Oien et al . (2020) show that many factors influence the ELA of modern cirque glaciers in Scandinavia, including topography, and the time transgressive occupation of cirques should be taken into account in palaeo‐ELA studies.…”

Section: Figurementioning

confidence: 99%

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Quantitative analyses of cirques on the Faroe Islands: evidence for time transgressive glacier occupation

Wallick

Principato

2020

Boreas

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This study presents the first analysis of ice‐free cirques on the Faroe Islands using a Geographical Information System (GIS) and the Automated Cirque Metric Extraction (ACME) tool. The length, width, area, circularity, mean aspect, mean slope, and elevation range, minimum, and maximum were calculated using ACME. Cirque distance to coastline was measured using ArcGIS. A total of 116 cirques were identified. Mean cirque length is 950 m and mean cirque width is 890 m. Average cirque area is 0.8 km2 and mean elevation is 386 m a.s.l. The modal orientation of the aspect of cirques is north‐northeast, with a vector mean of 7° and mean resultant length of 0.09. Aspect data have large dispersion, which shows evidence of cloudy ablation seasons in the past. The dispersion in aspect may also be related to the time transgressive nature of glacier occupation in these cirques. Past equilibrium‐line altitudes (ELAs) of cirque glaciers reconstructed with the minimum point method resulted in a mean palaeo‐ELA of 213 m a.s.l. Positive, linear relationships are observed between palaeo‐ELA and cirque distance to coastline. There are at least two possible interpretations of this relationship: (i) that the cirque formation is dependent on pre‐existing topography with cirques forming at the head of valleys, which occurs at higher elevations further inland, and (ii) that this relationship demonstrates the importance of access to moisture for glacier survival. A combination of both interpretations is also possible. Positive linear relationships are also observed between longitude and palaeo‐ELA indicative of palaeo‐precipitation patterns along an east–west gradient. Cirques on the Faroe Islands are smaller in length and width and present at lower elevations compared to cirques located in other regions of the world. The timing of glacial occupation in these cirques is not known, and the landforms likely formed over multiple glaciations.

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Section: Discussionmentioning

confidence: 99%

“…2019) or to the fact that the larger landmass size provides more topographic availability for cirques to form (Oien et al . 2020).…”

Section: Discussionmentioning

confidence: 99%

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Quantitative analyses of cirques on the Faroe Islands: evidence for time transgressive glacier occupation

Wallick

Principato

2020

Boreas

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“…The observed agreement between mountain peak elevations and reconstructed past ELAs, i.e., the glacial buzz-saw hypothesis (Brozović et al, 1997;Egholm et al, 2009;Mitchell and Montgomery, 2006), suggests glaciers might focus their erosion at or above the ELAs. However, the past ELAs are often reconstructed using the cirque floor elevations (Mitchell and Montgomery, 2006;Porter, 1989Porter, , 2000, and they might represent the average glacial conditions rather than the actual ELA determined by a specific climate (Barr and Spagnolo, 2015;Porter, 1989). Cirques are formed over multiple glacial-interglacial cycles, and the development of a cirque is thought to primarily occur during periods with modest climate when the glacier is restricted within the cirque and is mostly warm-based (Barr and Spagnolo, 2015).…”

Section: Ela Basal Thermal Regime and The Location Of Maximum Glacial Erosionmentioning

confidence: 99%

“…Cirques are formed over multiple glacial-interglacial cycles, and the development of a cirque is thought to primarily occur during periods with modest climate when the glacier is restricted within the cirque and is mostly warm-based (Barr and Spagnolo, 2015). The cirque floor elevations, therefore, are determined by the average intermediate conditions over multiple glacial-interglacial cycles (Barr and Spagnolo, 2015;Porter, 1989). As the cooling climate leads to more extensive glaciations, cirque enlargement might cease because the cirque is covered by cold-based ice, and the climatic conditions during these more extensive glaciation periods are not recorded in cirques.…”

Section: Ela Basal Thermal Regime and The Location Of Maximum Glacial Erosionmentioning

confidence: 99%

Climatic controls on mountain glacier basal thermal regimes dictate spatial patterns of glacial erosion

Lai

Anders

2021

Preprint

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<p>The basal thermal regime of glaciers is a first-order control on the spatial patterns of glacial erosion. Polythermal glaciers contain both cold-based portions that protect bedrock from erosion and warm-based portions that actively erode bedrock. Climatic controls on the thermal structures of mountain glaciers and the spatial patterns of glacial erosion has received little study. In this study, we aim to fill this gap by modeling the impact of various climatic conditions on glacier basal thermal regimes and patterns of glacial erosion in mountainous regions. We couple a sliding-dependent glacial erosion model with the Parallel Ice Sheet Model (PISM) to simulate the evolution of the glacier basal thermal regime and glacial erosion in a synthetic landscape. We find that glacial erosion patterns follow the patterns of the basal thermal regime. Cold temperature leads to limited glacial erosion at high elevations due to cold-based conditions. Increasing precipitation could overcome the impact of cold temperature on the basal thermal regime by accumulating thick ice and lowering the melting point of ice at the base of glaciers. High precipitation rates, therefore, tend to cause warm-based conditions at high elevations, resulting in intensive erosion near the peak of the mountain range. Previous studies often assess the impact of climate on the spatial patterns of glacial erosion by integrating climatic conditions into the equilibrium line altitudes (ELAs) of glaciers, and glacial erosion is suggested to be maximal around the ELAs. However, our results show that different climatic conditions could produce glaciers with similar ELAs but different patterns of basal thermal regime and glacial erosion, suggesting that there might not be any direct correlation between ELAs and glacial erosion patterns.</p>

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Glaciation in the highest parts of the Ukrainian Carpathians (Chornohora and Svydovets massifs) during the local last glacial maximum

Kłapyta

Zasadni

Dubis

et al. 2021

CATENA

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Climatic controls on the equilibrium-line altitudes of Scandinavian cirque glaciers

Cited by 13 publications

References 51 publications

Quantitative analyses of cirques on the Faroe Islands: evidence for time transgressive glacier occupation

Quantitative analyses of cirques on the Faroe Islands: evidence for time transgressive glacier occupation

Climatic controls on mountain glacier basal thermal regimes dictate spatial patterns of glacial erosion

Glaciation in the highest parts of the Ukrainian Carpathians (Chornohora and Svydovets massifs) during the local last glacial maximum

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