Lateglacial rock slope failures in north-west Ireland: age, causes and implications

Colin Ballantyne; Peter Wilson; Christoph Schnabel; Sheng Xu

doi:10.1002/jqs.2675

Lateglacial rock slope failures in north-west Ireland: age, causes and implications

Colin Ballantyne, Peter Wilson, Christoph Schnabel, Sheng Xu

Research output: Contribution to journal › Article › peer-review

Abstract

Nine postglacial quartzite rock slope failures (RSFs) in north-west Ireland were dated using cosmogenic ¹⁰Be. Weighted mean RSF ages range from 17.7 ± 0.9 to 12.5 ± 0.7 ka or 16.6 ± 0.7 to 11.7 ± 0.5 ka, depending on assumed ¹⁰Be
production rate. All dated RSFs occurred within ∼5000 years following
ice-sheet deglaciation at ∼17.4ka (∼16.3 ka) and all but two occurred
within 2000 years after deglaciation. The timing of RSFs rules out
glacial ‘debuttressing’, permafrost degradation and enhanced deglacial
cleft-water pressures as triggers of failure in most cases. We infer
that paraglacial stress release and associated fracture propagation were
critical in reducing rock masses to critical stability, although
earthquakes caused by Lateglacial glacio-isostatic rebound and/or
release of stored tectonic stresses may have triggered failure in some
or all cases. In conjunction with data from related studies, our results
imply that most undated RSFs outside the limit of Younger Dryas
glaciation in the British Isles are of Lateglacial age, and that
numerous Lateglacial RSFs occurred inside these limits, with subsequent
removal of debris by glaciers. They support the view that paraglacial
RSF activity in tectonically stable intraplate terrains was concentrated
within a few millennia following deglaciation.

Original language	English
Pages (from-to)	789-802
Number of pages	14
Journal	Journal of Quaternary Science
Volume	28
Issue number	8
Early online date	28 Nov 2013
DOIs	https://doi.org/10.1002/jqs.2675
Publication status	Published - Nov 2013

Keywords

10Be exposure dating
palaeoseismicity
paraglacial
rock slope failure
stress release

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10.1002/jqs.2675

Ballantyne_2013_JQS_Lateglacial
Copyright © 2013 John Wiley & Sons, Ltd. This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at http://onlinelibrary.wiley.com/doi/10.1002/jqs.2675/abstract
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Cite this

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title = "Lateglacial rock slope failures in north-west Ireland: age, causes and implications",

abstract = "Nine postglacial quartzite rock slope failures (RSFs) in north-west Ireland were dated using cosmogenic 10Be. Weighted mean RSF ages range from 17.7 ± 0.9 to 12.5 ± 0.7 ka or 16.6 ± 0.7 to 11.7 ± 0.5 ka, depending on assumed 10Be production rate. All dated RSFs occurred within ∼5000 years following ice-sheet deglaciation at ∼17.4ka (∼16.3 ka) and all but two occurred within 2000 years after deglaciation. The timing of RSFs rules out glacial {\textquoteleft}debuttressing{\textquoteright}, permafrost degradation and enhanced deglacial cleft-water pressures as triggers of failure in most cases. We infer that paraglacial stress release and associated fracture propagation were critical in reducing rock masses to critical stability, although earthquakes caused by Lateglacial glacio-isostatic rebound and/or release of stored tectonic stresses may have triggered failure in some or all cases. In conjunction with data from related studies, our results imply that most undated RSFs outside the limit of Younger Dryas glaciation in the British Isles are of Lateglacial age, and that numerous Lateglacial RSFs occurred inside these limits, with subsequent removal of debris by glaciers. They support the view that paraglacial RSF activity in tectonically stable intraplate terrains was concentrated within a few millennia following deglaciation.",

keywords = "10Be exposure dating, palaeoseismicity, paraglacial, rock slope failure, stress release",

author = "Colin Ballantyne and Peter Wilson and Christoph Schnabel and Sheng Xu",

note = "This research was supported by the NERC Cosmogenic Isotope Analysis Facility through an award for sample preparation and analysis (CIAF project 9046.0308)",

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T1 - Lateglacial rock slope failures in north-west Ireland

T2 - age, causes and implications

AU - Ballantyne, Colin

AU - Wilson, Peter

AU - Schnabel, Christoph

AU - Xu, Sheng

N1 - This research was supported by the NERC Cosmogenic Isotope Analysis Facility through an award for sample preparation and analysis (CIAF project 9046.0308)

PY - 2013/11

Y1 - 2013/11

N2 - Nine postglacial quartzite rock slope failures (RSFs) in north-west Ireland were dated using cosmogenic 10Be. Weighted mean RSF ages range from 17.7 ± 0.9 to 12.5 ± 0.7 ka or 16.6 ± 0.7 to 11.7 ± 0.5 ka, depending on assumed 10Be production rate. All dated RSFs occurred within ∼5000 years following ice-sheet deglaciation at ∼17.4ka (∼16.3 ka) and all but two occurred within 2000 years after deglaciation. The timing of RSFs rules out glacial ‘debuttressing’, permafrost degradation and enhanced deglacial cleft-water pressures as triggers of failure in most cases. We infer that paraglacial stress release and associated fracture propagation were critical in reducing rock masses to critical stability, although earthquakes caused by Lateglacial glacio-isostatic rebound and/or release of stored tectonic stresses may have triggered failure in some or all cases. In conjunction with data from related studies, our results imply that most undated RSFs outside the limit of Younger Dryas glaciation in the British Isles are of Lateglacial age, and that numerous Lateglacial RSFs occurred inside these limits, with subsequent removal of debris by glaciers. They support the view that paraglacial RSF activity in tectonically stable intraplate terrains was concentrated within a few millennia following deglaciation.

AB - Nine postglacial quartzite rock slope failures (RSFs) in north-west Ireland were dated using cosmogenic 10Be. Weighted mean RSF ages range from 17.7 ± 0.9 to 12.5 ± 0.7 ka or 16.6 ± 0.7 to 11.7 ± 0.5 ka, depending on assumed 10Be production rate. All dated RSFs occurred within ∼5000 years following ice-sheet deglaciation at ∼17.4ka (∼16.3 ka) and all but two occurred within 2000 years after deglaciation. The timing of RSFs rules out glacial ‘debuttressing’, permafrost degradation and enhanced deglacial cleft-water pressures as triggers of failure in most cases. We infer that paraglacial stress release and associated fracture propagation were critical in reducing rock masses to critical stability, although earthquakes caused by Lateglacial glacio-isostatic rebound and/or release of stored tectonic stresses may have triggered failure in some or all cases. In conjunction with data from related studies, our results imply that most undated RSFs outside the limit of Younger Dryas glaciation in the British Isles are of Lateglacial age, and that numerous Lateglacial RSFs occurred inside these limits, with subsequent removal of debris by glaciers. They support the view that paraglacial RSF activity in tectonically stable intraplate terrains was concentrated within a few millennia following deglaciation.

KW - 10Be exposure dating

KW - palaeoseismicity

KW - paraglacial

KW - rock slope failure

KW - stress release

U2 - 10.1002/jqs.2675

DO - 10.1002/jqs.2675

M3 - Article

SN - 0267-8179

VL - 28

SP - 789

EP - 802

JO - Journal of Quaternary Science

JF - Journal of Quaternary Science

IS - 8

ER -

Lateglacial rock slope failures in north-west Ireland: age, causes and implications

Abstract

Keywords

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