Schmidt Hammer exposure dating (SHED): Establishment and implications for the retreat of the last British Ice Sheet

M. D. Tomkins, J. M. Dortch, P. D. Hughes

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

Ninety-eight surfaces related to the retreat of the British Ice Sheet (BIS) and dated using Terrestrial Cosmogenic Nuclide Dating (TCND) were sampled using the Schmidt Hammer to expand on relative dating techniques and establish Schmidt Hammer exposure dating (SHED) as an effective method for dating glacial landforms in the UK. The BIS is an effective analogue for contemporary glacial systems but our understanding of its retreat under changing climate conditions is constrained by a limited number of dates obtained from existing methods (14C, OSL). These methods are restricted in their application to glacial environments and while TCND has addressed this to some degree, its cost and potential for outliers encourage the establishment of new techniques. SHED fulfils this requirement by providing a cost-efficient method for obtaining numerous direct ages that are of comparable accuracy and precision to TCND. A multi-lithology approach has established that many rock types are unsuitable for numerical dating. However, a robust calibration curve was generated (R2 = 0.81, p = < 0.01) for granite surfaces and applied to 31 undated granite erratics on Shap Fell, NW England. SHED indicates that BIS retreat occurred at 16.5 ± 0.5 ka, a conclusion which supports our current understanding of regional deglaciation and indicates that SHED can be a valuable and cost-effective geochronological tool.

Original languageEnglish
Pages (from-to)46-60
Number of pages15
JournalQuaternary Geochronology
Volume33
DOIs
StatePublished - Jun 1 2016

Bibliographical note

Funding Information:
We would like to thank C. Ballantyne, T. Bradwell, J. Everest, D. Small and P. Wilson for providing sample photographs which were essential when conducting fieldwork. D. Fabel also kindly provided unpublished calibration data for the LL LPR which permitted exposure age recalibration. We would also like to thank D. Tomkins whose assistance during fieldwork was essential to this research. This study was partially funded by the University of Manchester Zochonis Travel Award 2013/2014 and an Undergraduate Dissertation Bursary provided by the Manchester Geographical Society. Hughes and Dortch would like to thank the University of Manchester Research Stimulation Fund.

Publisher Copyright:
© 2016 Elsevier B.V.

Keywords

  • Be dating
  • British Ice Sheet
  • British-Irish Ice Sheet
  • Glacial chronology
  • Schmidt hammer exposure dating
  • TCN dating

ASJC Scopus subject areas

  • Geology
  • Stratigraphy
  • Earth and Planetary Sciences (miscellaneous)

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