Rapid age assessment of glacial landforms in the Pyrenees using Schmidt hammer exposure dating (SHED). Issue 1 (2nd April 2018)

• Record Type: Journal Article
• Authors: Tomkins, Matt D.; Dortch, Jason M.; Hughes, Philip D.; Huck, Jonny J.; Stimson, Andrew G.; Delmas, Magali; Calvet, Marc; Pallàs, Raimon
• Is Part Of: Quaternary research. Volume 90:Issue 1(2018)
• Page Start: 26
• Page End: 37
• Publication Date: 2018-04-02
• Subjects: Schmidt hammer exposure dating, -- Pyrenees, -- Glacier chronology, -- Geomorphology, -- Terrestrial cosmogenic nuclide dating, -- Last glacial maximum; Geology, Stratigraphic -- Quaternary -- Periodicals; Glacial epoch -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; Époque glaciaire -- Périodiques; Geology, Stratigraphic; Glacial epoch; Quaternary Geologic Period; Electronic journals; Periodicals; 551.79
• DOI: 10.1017/qua.2018.12
• Languages: English
• ISSNs: 0033-5894

Abstract

Abstract: Schmidt hammer (SH) sampling of 54 10 Be-dated granite surfaces from the Pyrenees reveals a clear relationship between exposure and weathering through time (n=52, R 2 =0.96, P <0.01) and permits the use of the SH as a numerical dating tool. To test this 10 Be-SH calibration curve, 100 surfaces were sampled from five ice-front positions in the Têt catchment, eastern Pyrenees, with results verified against independent 10 Be and 14 C ages. Gaussian modelling differentiates Holocene (9.4±0.6 ka), Younger Dryas (12.6±0.9 ka), Oldest Dryas (16.1±0.5 ka), last glacial maximum (LGM; 24.8±0.9 ka) and Würmian maximum ice extent stages (MIE; 40.9±1.1 ka). These data confirm comparable glacier lengths during the LGM and MIE (~300 m difference), in contrast to evidence from the western Pyrenees (≥15 km), reflecting the relative influence of Atlantic and Mediterranean climates. Moreover, Pyrenean glaciers advanced significantly during the LGM, with a local maximum at ~25 ka, driven by growth of the Laurentide Ice Sheet, southward advection of the polar front, and a solar radiation minimum in the Northern Hemisphere. This calibration curve is available online (http://shed.earth ) to enable wider application of this method throughout the Pyrenees.