Reconstruction and regional significance of the Coire Breac palaeoglacier, Glen Esk, eastern Grampian Highlands, Scotland

Martin P. Kirkbride, Wishart A. Mitchell, Mhari Barnes

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    Abstract

    We present a glaciological and climatic reconstruction of a former glacier in Coire Breac, an isolated cirque within the Eastern Grampian plateau of Scotland, 5 km from the Highland edge. Published glacier reconstructions of presumed Younger Dryas-age glaciers in this area show that equilibrium line altitudes decreased steeply towards the east coast, implying a maritime glacial environment. Extrapolation of the ELA trend surface implies that glaciers should have existed in suitable locations on the plateau, a landscape little modified by glaciation. In Coire Breac, a 0.35 km2 cirque glacier existed with an equilibrium line altitude of 487 ± 15 m above present sea level. The equilibrium line altitude matches closely the extrapolated regional equilibriumline altitude trend surface for Younger Dryas Stadial glaciers. The mean glacier thickness of 24 m gives an ice volume of 7.8 x 106 m3, and a maximum basal shear stress of c. 100 kPa-1. Ablation gradient was c. -0.0055 m m-1, with a mean July temperature at the equilibrium line altitude of c. 5.1°C. The reconstruction implies an arctic maritime climate of low precipitation with local accumulation enhanced by blown snow, which may explain the absence of other contemporary glaciers nearby. Reconstructed ice flow lines show zones of flow concentration around the lower ice margin which help to explain the distribution of depositional facies associated with a former debris cover which may have delayed eventual glacier retreat. No moraines in the area have been dated, so palaeoclimatic interpretations remain provisional, and a pre-Lateglacial Interstadial age cannot be ruled out.
    Original languageEnglish
    Pages (from-to)563-577
    Number of pages15
    JournalGeografiska Annaler: Series A
    Volume97
    Issue number3
    Early online date11 Feb 2015
    DOIs
    Publication statusPublished - Sep 2015

    Fingerprint

    glacier
    reconstruction
    equilibrium line
    cirque
    Younger Dryas
    trend
    Arctic
    climate
    plateau
    glacial environment
    glacier retreat
    interpretation
    ice margin
    ice flow
    present
    interstadial
    ablation
    shear stress
    glaciation
    snow

    Keywords

    • Glacier reconstruction
    • Grampian Highlands
    • equilibrium-line altitude
    • Younger Dryas
    • palaeoclimatic reconstruction

    Cite this

    @article{35aebd0d082d4727bb7b790d92a7a6d9,
    title = "Reconstruction and regional significance of the Coire Breac palaeoglacier, Glen Esk, eastern Grampian Highlands, Scotland",
    abstract = "We present a glaciological and climatic reconstruction of a former glacier in Coire Breac, an isolated cirque within the Eastern Grampian plateau of Scotland, 5 km from the Highland edge. Published glacier reconstructions of presumed Younger Dryas-age glaciers in this area show that equilibrium line altitudes decreased steeply towards the east coast, implying a maritime glacial environment. Extrapolation of the ELA trend surface implies that glaciers should have existed in suitable locations on the plateau, a landscape little modified by glaciation. In Coire Breac, a 0.35 km2 cirque glacier existed with an equilibrium line altitude of 487 ± 15 m above present sea level. The equilibrium line altitude matches closely the extrapolated regional equilibriumline altitude trend surface for Younger Dryas Stadial glaciers. The mean glacier thickness of 24 m gives an ice volume of 7.8 x 106 m3, and a maximum basal shear stress of c. 100 kPa-1. Ablation gradient was c. -0.0055 m m-1, with a mean July temperature at the equilibrium line altitude of c. 5.1°C. The reconstruction implies an arctic maritime climate of low precipitation with local accumulation enhanced by blown snow, which may explain the absence of other contemporary glaciers nearby. Reconstructed ice flow lines show zones of flow concentration around the lower ice margin which help to explain the distribution of depositional facies associated with a former debris cover which may have delayed eventual glacier retreat. No moraines in the area have been dated, so palaeoclimatic interpretations remain provisional, and a pre-Lateglacial Interstadial age cannot be ruled out.",
    keywords = "Glacier reconstruction, Grampian Highlands, equilibrium-line altitude, Younger Dryas, palaeoclimatic reconstruction",
    author = "Kirkbride, {Martin P.} and Mitchell, {Wishart A.} and Mhari Barnes",
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    }

    Reconstruction and regional significance of the Coire Breac palaeoglacier, Glen Esk, eastern Grampian Highlands, Scotland. / Kirkbride, Martin P.; Mitchell, Wishart A.; Barnes, Mhari.

    In: Geografiska Annaler: Series A, Vol. 97, No. 3, 09.2015, p. 563-577.

    Research output: Contribution to journalArticle

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    T1 - Reconstruction and regional significance of the Coire Breac palaeoglacier, Glen Esk, eastern Grampian Highlands, Scotland

    AU - Kirkbride, Martin P.

    AU - Mitchell, Wishart A.

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    N2 - We present a glaciological and climatic reconstruction of a former glacier in Coire Breac, an isolated cirque within the Eastern Grampian plateau of Scotland, 5 km from the Highland edge. Published glacier reconstructions of presumed Younger Dryas-age glaciers in this area show that equilibrium line altitudes decreased steeply towards the east coast, implying a maritime glacial environment. Extrapolation of the ELA trend surface implies that glaciers should have existed in suitable locations on the plateau, a landscape little modified by glaciation. In Coire Breac, a 0.35 km2 cirque glacier existed with an equilibrium line altitude of 487 ± 15 m above present sea level. The equilibrium line altitude matches closely the extrapolated regional equilibriumline altitude trend surface for Younger Dryas Stadial glaciers. The mean glacier thickness of 24 m gives an ice volume of 7.8 x 106 m3, and a maximum basal shear stress of c. 100 kPa-1. Ablation gradient was c. -0.0055 m m-1, with a mean July temperature at the equilibrium line altitude of c. 5.1°C. The reconstruction implies an arctic maritime climate of low precipitation with local accumulation enhanced by blown snow, which may explain the absence of other contemporary glaciers nearby. Reconstructed ice flow lines show zones of flow concentration around the lower ice margin which help to explain the distribution of depositional facies associated with a former debris cover which may have delayed eventual glacier retreat. No moraines in the area have been dated, so palaeoclimatic interpretations remain provisional, and a pre-Lateglacial Interstadial age cannot be ruled out.

    AB - We present a glaciological and climatic reconstruction of a former glacier in Coire Breac, an isolated cirque within the Eastern Grampian plateau of Scotland, 5 km from the Highland edge. Published glacier reconstructions of presumed Younger Dryas-age glaciers in this area show that equilibrium line altitudes decreased steeply towards the east coast, implying a maritime glacial environment. Extrapolation of the ELA trend surface implies that glaciers should have existed in suitable locations on the plateau, a landscape little modified by glaciation. In Coire Breac, a 0.35 km2 cirque glacier existed with an equilibrium line altitude of 487 ± 15 m above present sea level. The equilibrium line altitude matches closely the extrapolated regional equilibriumline altitude trend surface for Younger Dryas Stadial glaciers. The mean glacier thickness of 24 m gives an ice volume of 7.8 x 106 m3, and a maximum basal shear stress of c. 100 kPa-1. Ablation gradient was c. -0.0055 m m-1, with a mean July temperature at the equilibrium line altitude of c. 5.1°C. The reconstruction implies an arctic maritime climate of low precipitation with local accumulation enhanced by blown snow, which may explain the absence of other contemporary glaciers nearby. Reconstructed ice flow lines show zones of flow concentration around the lower ice margin which help to explain the distribution of depositional facies associated with a former debris cover which may have delayed eventual glacier retreat. No moraines in the area have been dated, so palaeoclimatic interpretations remain provisional, and a pre-Lateglacial Interstadial age cannot be ruled out.

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