Age determination of glacially-transported boulders in Ireland and Scotland using Schmidt-hammer exposure-age dating (SHD) and terrestrial cosmogenic nuclide (TCN) exposure-age dating

Peter Wilson, Paul Dunlop, Chris Millar, Frances Wilson

Research output: Contribution to journalArticle

Abstract

Schmidt-hammer exposure-age dating (SHD) was applied at 15 sites with glacially-transported granite boulders in parts of northern and western Ireland and southwest Scotland that had been exposed by retreat of the last British-Irish Ice Sheet (BIIS) or Younger Dryas (YD) ice masses. Seven of these surfaces had previously been dated using terrestrial cosmogenic nuclide (TCN) exposure-age dating. Application of the granite calibration equation of Tomkins et al. (2018c) indicated a close correspondence between the SHD ages and the TCN ages (within 1σ or 2σ uncertainties). These findings demonstrate that SHD ages can be of comparable accuracy, precision and reliability to TCN ages, and are a strong argument for the more extensive use of SHD in some Quaternary dating projects. However, surface ages obtained by both SHD and TCN dating should not be accepted uncritically, but must be assessed in relation to the wider geological, geomorphological and geochronological evidence. Evaluation of eight SHD ages, for which corresponding TCN ages are not available, indicate that most are consistent with current theory and field evidence, but some anomalous age estimates occur.
LanguageEnglish
JournalQuaternary Research
Publication statusAccepted/In press - 19 Feb 2019

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age determination
granite
dating
exposure
Younger Dryas
ice sheet
calibration
ice

Keywords

  • Exposure-age dating
  • Glacially-transported boulders
  • Schmidt hammer
  • Terrestrial Cosmogenic Nuclides
  • British-Irish Ice Sheet

Cite this

@article{5718e3279e9a4d69be06224859efaefb,
title = "Age determination of glacially-transported boulders in Ireland and Scotland using Schmidt-hammer exposure-age dating (SHD) and terrestrial cosmogenic nuclide (TCN) exposure-age dating",
abstract = "Schmidt-hammer exposure-age dating (SHD) was applied at 15 sites with glacially-transported granite boulders in parts of northern and western Ireland and southwest Scotland that had been exposed by retreat of the last British-Irish Ice Sheet (BIIS) or Younger Dryas (YD) ice masses. Seven of these surfaces had previously been dated using terrestrial cosmogenic nuclide (TCN) exposure-age dating. Application of the granite calibration equation of Tomkins et al. (2018c) indicated a close correspondence between the SHD ages and the TCN ages (within 1σ or 2σ uncertainties). These findings demonstrate that SHD ages can be of comparable accuracy, precision and reliability to TCN ages, and are a strong argument for the more extensive use of SHD in some Quaternary dating projects. However, surface ages obtained by both SHD and TCN dating should not be accepted uncritically, but must be assessed in relation to the wider geological, geomorphological and geochronological evidence. Evaluation of eight SHD ages, for which corresponding TCN ages are not available, indicate that most are consistent with current theory and field evidence, but some anomalous age estimates occur.",
keywords = "Exposure-age dating, Glacially-transported boulders, Schmidt hammer, Terrestrial Cosmogenic Nuclides, British-Irish Ice Sheet",
author = "Peter Wilson and Paul Dunlop and Chris Millar and Frances Wilson",
year = "2019",
month = "2",
day = "19",
language = "English",
journal = "Quaternary Research",
issn = "0033-5894",
publisher = "Cambridge University Press",

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TY - JOUR

T1 - Age determination of glacially-transported boulders in Ireland and Scotland using Schmidt-hammer exposure-age dating (SHD) and terrestrial cosmogenic nuclide (TCN) exposure-age dating

AU - Wilson, Peter

AU - Dunlop, Paul

AU - Millar, Chris

AU - Wilson, Frances

PY - 2019/2/19

Y1 - 2019/2/19

N2 - Schmidt-hammer exposure-age dating (SHD) was applied at 15 sites with glacially-transported granite boulders in parts of northern and western Ireland and southwest Scotland that had been exposed by retreat of the last British-Irish Ice Sheet (BIIS) or Younger Dryas (YD) ice masses. Seven of these surfaces had previously been dated using terrestrial cosmogenic nuclide (TCN) exposure-age dating. Application of the granite calibration equation of Tomkins et al. (2018c) indicated a close correspondence between the SHD ages and the TCN ages (within 1σ or 2σ uncertainties). These findings demonstrate that SHD ages can be of comparable accuracy, precision and reliability to TCN ages, and are a strong argument for the more extensive use of SHD in some Quaternary dating projects. However, surface ages obtained by both SHD and TCN dating should not be accepted uncritically, but must be assessed in relation to the wider geological, geomorphological and geochronological evidence. Evaluation of eight SHD ages, for which corresponding TCN ages are not available, indicate that most are consistent with current theory and field evidence, but some anomalous age estimates occur.

AB - Schmidt-hammer exposure-age dating (SHD) was applied at 15 sites with glacially-transported granite boulders in parts of northern and western Ireland and southwest Scotland that had been exposed by retreat of the last British-Irish Ice Sheet (BIIS) or Younger Dryas (YD) ice masses. Seven of these surfaces had previously been dated using terrestrial cosmogenic nuclide (TCN) exposure-age dating. Application of the granite calibration equation of Tomkins et al. (2018c) indicated a close correspondence between the SHD ages and the TCN ages (within 1σ or 2σ uncertainties). These findings demonstrate that SHD ages can be of comparable accuracy, precision and reliability to TCN ages, and are a strong argument for the more extensive use of SHD in some Quaternary dating projects. However, surface ages obtained by both SHD and TCN dating should not be accepted uncritically, but must be assessed in relation to the wider geological, geomorphological and geochronological evidence. Evaluation of eight SHD ages, for which corresponding TCN ages are not available, indicate that most are consistent with current theory and field evidence, but some anomalous age estimates occur.

KW - Exposure-age dating

KW - Glacially-transported boulders

KW - Schmidt hammer

KW - Terrestrial Cosmogenic Nuclides

KW - British-Irish Ice Sheet

M3 - Article

JO - Quaternary Research

T2 - Quaternary Research

JF - Quaternary Research

SN - 0033-5894

ER -