Rapid age assessment of glacial landforms in the Pyrenees using Schmidt hammer exposure dating (SHED)

• Published in: Quaternary Research
• Main Authors: Tomkins, Matt, Dortch, Jason, Hughes, Philip, Huck, Jonny, Stimson, Andrew, Delmas, Magali, Calvet, Marc, Pallas, Raimon
• Other Authors: University of Manchester Manchester, University of Kentucky (UK), Université de Perpignan Via Domitia (UPVD), Histoire naturelle de l'Homme préhistorique (HNHP), Muséum national d'Histoire naturelle (MNHN)-Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Departament de Geodinamica i Geofısica, Facultat de Geologia, Universitat de Barcelona (UB)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: Geomorphology; Glacier chronology; Schmidt hammer exposure dating; Terrestrial cosmogenic nuclide dating; Last glacial maximum; Marteau de Schmidt; Pyrénées; Chronologie de l'Âge de Glace; Géomorphologie; Datation des nucléides cosmogènes terrestres; Dernier maximum glacial; [SDU]Sciences of the Universe [physics]; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology; Ice Sheet
• Online Access: https://hal.science/hal-02148042; https://doi.org/10.1017/qua.2018.12

International audience Schmidt hammer (SH) sampling of 54 10 Be-dated granite surfaces from the Pyrenees reveals a clear relationship betweenexposure and weathering through time (n=52, R 2 =0.96, P<0.01) and permits the use of the SH as a numerical datingtool. To test this10 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±0.6ka), Younger Dryas (12.6±0.9ka), Oldest Dryas (16.1±0.5ka), last glacial maximum (LGM; 24.8±0.9ka)and Würmian maximum ice extent stages (MIE; 40.9±1.1ka). These data confirm comparable glacier lengths during theLGM and MIE (~300m difference), in contrast to evidence from the western Pyrenees (≥15km), reflecting the relativeinfluence of Atlantic and Mediterranean climates. Moreover, Pyrenean glaciers advanced significantly during the LGM,with a local maximum at ~25ka, 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) toenable wider application of this method throughout the Pyrenees.