A critical appraisal of allometric growth among alpine cirques based on multivariate statistics and spatial analysis

Delmas, Magali; Gunnell, Yanni; Calvet, Marc

doi:10.1016/j.geomorph.2014.10.021

Cited by 29 publications

(42 citation statements)

References 59 publications

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“…4e). Other classification schemes also exist, for example Delmas et al (2015) differentiate between elementary first-order cirques; second-order (cirques-in-cirques); and third-order cirques (cirques-in-cirques-in-cirques).…”

Section: Cirque Properties 21 Cirque Definitionmentioning

confidence: 99%

“…Glacial cirques (hereafter 'cirques') are armchair-shaped hollows typically found in upland settings, and largely owe their shape to erosion by relatively small (cirque type) glaciers. Cirques have been the focus of research for over 150 years (e.g., Darwin, 1842;Tyndall, 1862;Gastaldi, 1873), and the past decade has seen a resurgence of interest in their analysis (e.g., Evans, 2006a;Delmas et al, 2015;Mitchell and Humphries, 2015). A number of studies have focused on understanding the mechanisms and processes responsible for cirque formation, by establishing what accounts for their distribution and characteristic morphology (e.g., Graf, 1976;Gordon, 1977;Jansson et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

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Glacial cirques as palaeoenvironmental indicators: Their potential and limitations

Barr

Spagnolo

2015

Earth-Science Reviews

103

106

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Glacial cirques are armchair-shaped erosional hollows, typified by steep headwalls and, often, overdeepened floors. They reflect former regions of glacier initiation, and their distribution is, therefore, linked to palaeoclimate. Because of this association, cirques can be analysed for the information they provide about past environments, an approach that has a strong heritage, and has seen resurgence over recent years. This paper provides a critical assessment of what cirques can tell us about past environments, and considers their reliability as palaeoenvironmental proxies. Specific focus is placed on information that can be obtained from consideration of cirque distribution, aspect, altitude, and morphometry. The paper highlights the fact that cirques potentially provide information about the style, duration and intensity of former glaciation, as well as information about past temperatures, precipitation gradients, cloud-cover and wind directions. In all, cirques are considered a valuable source of palaeoenvironmental information (if used judiciously), particularly as they are ubiquitous within formerly glaciated mountain ranges globally, thus making regional or even global scale studies possible. Furthermore, cirques often occupy remote and inaccessible regions where other palaeoenvironmental proxies may be limited or lacking. "Custom has not yet made a decision as to the universal name of this feature of mountain sculpture. Many countries furnish their own local names, and the word has been parenthetically translated into three or four languages […]. In the Scottish Highlands, corry is the prevailing word;

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Section: Cirque Properties 21 Cirque Definitionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Glacial cirques as palaeoenvironmental indicators: Their potential and limitations

Barr

Spagnolo

2015

Earth-Science Reviews

103

106

View full text Add to dashboard Cite

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“…Since cirque formation is limited to regions where lithology has 'allowed' bedrock to be eroded into bowl-shaped hollows, regional variations in bedrock erodibility can potentially influence cirque shape (see Delmas et al, 2014Delmas et al, , 2015 and altitude (see Mîndrescu and Evans, 2014). However, Barr and Spagnolo (2013) , 1990;Bindeman et al, 2010).…”

Section: Geological Controls On Cirque Floor Altitudesmentioning

confidence: 99%

Understanding controls on cirque floor altitudes: Insights from Kamchatka

Barr

Spagnolo

2015

Geomorphology

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Glacial cirques reflect former regions of glacier initiation, and are therefore used as indicators of past climate. One specific way in which palaeoclimatic information is obtained from cirques is by analysing their elevations, on the assumption that cirque floor altitudes are a proxy for climatically controlled equilibrium-line altitudes (ELAs) during former periods of small scale (cirque-type) glaciation. However, specific controls on cirque altitudes are rarely assessed, and the validity of using cirque floor altitudes as a source of palaeoclimatic information remains open to question. In order to address this, here we analyse the distribution of 3520 ice-free cirques on the Kamchatka Peninsula (eastern Russia), and assess various controls on their floor altitudes. In addition, we analyse controls on the mid-altitudes of 503 modern glaciers, currently identifiable on the peninsula, and make comparisons with the cirque altitude data. The main study findings are that cirque floor altitudes increase steeply inland from the Pacific, suggesting that moisture availability (i.e., proximity to the coastline) played a key role in regulating the altitudes at which former (cirque-forming) glaciers were able to initiate. Other factors, such as latitude, aspect, topography, geology and neo-tectonics seem to have played a limited (but not insignificant) role in regulating cirque floor altitudes, though southfacing cirques are typically higher than their north-facing equivalents, potentially reflecting the impact of prevailing wind directions (from the SSE) and/or variations in solar radiation on the altitudes at A C C E P T E D M A N U S C R I P TACCEPTED MANUSCRIPT 2 which former glaciers were able to initiate. Trends in glacier and cirque altitudes across the peninsula are typically comparable (i.e., values typically rise from both the north and south, inland from the Pacific coastline, and where glaciers/cirques are south-facing), yet the relationship with latitude is stronger for modern glaciers, and the relationship with distance to the coastline (and to a lesser degree with aspect) is notably weaker. These differences suggest that former glacier initiation (leading to cirque formation) was largely regulated by moisture availability (during winter months) and the control this exerted on accumulation; whilst the survival of modern glaciers is also strongly regulated by the variety of climatic and non climatic factors that control ablation. As a result, relationships between modern glacier mid-altitudes and peninsula-wide climatic trends are more difficult to identify than when cirque floor altitudes are considered (i.e., cirque-forming glaciers were likely in climatic equilibrium, whereas modern glaciers may not be).

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“…The geographical variations of these metrics in relation to aspect have also been used to infer different styles of glacial activity (Barr and Spagnolo, 2013) as well as the influence of periglacial processes on cirque development (Delmas, 2015). Aspect in itself can be analysed to understand past patterns in solar radiation and, specifically, differential cloudiness between morning and afternoon (Evans, 1977(Evans, , 2006.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

ACME, a GIS tool for Automated Cirque Metric Extraction

et al. 2017

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Regional scale studies of glacial cirque metrics provide key insights on the (palaeo)environment related to the formation of these erosional landforms. The growing availability of high resolution terrain models means that more glacial cirques can be identified and mapped in the future.However, the extraction of their metrics still largely relies on time consuming manual techniques or the combination of, more or less obsolete, GIS tools. In this paper, a newly coded toolbox is provided for the automated, and comparatively quick, extraction of 16 key glacial cirque metrics; including length, width, circularity, planar and 3D area, elevation, slope, aspect, plan closure and hypsometry.The set of tools, named ACME (Automated Cirque Metric Extraction), is coded in Python, runs in one of the most commonly used GIS packages (ArcGIS) and has a user friendly interface. A polygon layer of mapped cirques is required for all metrics, while a Digital Terrain Model and a point layer of cirque threshold midpoints are needed to run some of the tools. Results from ACME are comparable to those from other techniques and can be obtained rapidly, allowing large cirque datasets to be analysed and potentially important regional trends highlighted.

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A critical appraisal of allometric growth among alpine cirques based on multivariate statistics and spatial analysis

Cited by 29 publications

References 59 publications

Glacial cirques as palaeoenvironmental indicators: Their potential and limitations

Glacial cirques as palaeoenvironmental indicators: Their potential and limitations

Understanding controls on cirque floor altitudes: Insights from Kamchatka

ACME, a GIS tool for Automated Cirque Metric Extraction

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