Articles | Volume 10, issue 6
The Cryosphere, 10, 2779–2797, 2016

Special issue: International Partnerships in Ice Core Sciences (IPICS) Second...

The Cryosphere, 10, 2779–2797, 2016

Research article 17 Nov 2016

Research article | 17 Nov 2016

Age of the Mt. Ortles ice cores, the Tyrolean Iceman and glaciation of the highest summit of South Tyrol since the Northern Hemisphere Climatic Optimum

Paolo Gabrielli1,2, Carlo Barbante3,4,5, Giuliano Bertagna1, Michele Bertó3, Daniel Binder6, Alberto Carton7, Luca Carturan8, Federico Cazorzi9, Giulio Cozzi3,4, Giancarlo Dalla Fontana8, Mary Davis1, Fabrizio De Blasi8, Roberto Dinale10, Gianfranco Dragà11, Giuliano Dreossi3, Daniela Festi12, Massimo Frezzotti13, Jacopo Gabrieli3,4, Stephan P. Galos14, Patrick Ginot15,16, Petra Heidenwolf12, Theo M. Jenk17, Natalie Kehrwald18, Donald Kenny1, Olivier Magand15,16, Volkmar Mair19, Vladimir Mikhalenko20, Ping Nan Lin1, Klaus Oeggl12, Gianni Piffer21, Mirko Rinaldi21, Ulrich Schotterer22, Margit Schwikowski17, Roberto Seppi23, Andrea Spolaor3, Barbara Stenni3, David Tonidandel19, Chiara Uglietti17, Victor Zagorodnov1, Thomas Zanoner7, and Piero Zennaro3 Paolo Gabrielli et al.
  • 1Byrd Polar and Climate Research Center, The Ohio State University, Columbus, 43210, USA
  • 2School of Earth Sciences, The Ohio State University, 275 Mendenhall Laboratory, Columbus, 43210, USA
  • 3Department of Environmental Sciences, Informatics and Statistics, Ca' Foscari University of Venice, 30170 Venice-Mestre, Italy
  • 4Istituto per la Dinamica dei Processi Ambientali-CNR, 30170 Venice-Mestre, Italy
  • 5Accademia Nazionale dei Lincei, 00196 Rome, Italy
  • 6Climate Research Section, Central Institute for Meteorology and Geodynamics ZAMG, 1190 Vienna, Austria
  • 7Department of Geosciences, University of Padova, 35131 Padova, Italy
  • 8Department of Land, Environment, Agriculture and Forestry, University of Padova, Agripolis, 35020 Legnaro, Italy
  • 9Dipartimento di Scienze Agro-Alimentari, Ambientali e Animali, Università di Udine, 33100 Udine, Italy
  • 10Ufficio Idrografico, Provincia Autonoma di Bolzano, 39100 Bolzano, Italy
  • 11Geologin, 39040 Varna, Italy
  • 12Institute for Botany, University of Innsbruck, 6020 Innsbruck, Austria
  • 13ENEA, 00196 Rome, Italy
  • 14Institute of Atmospheric and Cryospheric Sciences, University of Innsbruck, 6020 Innsbruck, Austria
  • 15Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), CNRS, 38041 Grenoble, France
  • 16University Grenoble Alpes, 38041 Grenoble, France
  • 17Laboratory of Environmental Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
  • 18Geosciences and Environmental Change Science Center, U.S. Geological Survey, Denver, 80225, USA
  • 19Ufficio Geologia e Prove materiali, Provincia Autonoma di Bolzano, 39053 Kardano, Italy
  • 20Institute of Geography, Russian Academy of Sciences, 119017 Moscow, Russia
  • 21Waterstones Geomonitoring, 39044 Egna, Italy
  • 22University of Bern, 3012 Bern, Switzerland
  • 23Department of Earth and Environmental Sciences, University of Pavia, 27100 Pavia, Italy

Abstract. In 2011 four ice cores were extracted from the summit of Alto dell'Ortles (3859 m), the highest glacier of South Tyrol in the Italian Alps. This drilling site is located only 37 km southwest from where the Tyrolean Iceman,  ∼ 5.3 kyrs old, was discovered emerging from the ablating ice field of Tisenjoch (3210 m, near the Italian–Austrian border) in 1991. The excellent preservation of this mummy suggested that the Tyrolean Iceman was continuously embedded in prehistoric ice and that additional ancient ice was likely preserved elsewhere in South Tyrol. Dating of the ice cores from Alto dell'Ortles based on 210Pb, tritium, beta activity and 14C determinations, combined with an empirical model (COPRA), provides evidence for a chronologically ordered ice stratigraphy from the modern glacier surface down to the bottom ice layers with an age of  ∼ 7 kyrs, which confirms the hypothesis. Our results indicate that the drilling site has continuously been glaciated on frozen bedrock since  ∼ 7 kyrs BP. Absence of older ice on the highest glacier of South Tyrol is consistent with the removal of basal ice from bedrock during the Northern Hemisphere Climatic Optimum (6–9 kyrs BP), the warmest interval in the European Alps during the Holocene. Borehole inclinometric measurements of the current glacier flow combined with surface ground penetration radar (GPR) measurements indicate that, due to the sustained atmospheric warming since the 1980s, an acceleration of the glacier Alto dell'Ortles flow has just recently begun. Given the stratigraphic–chronological continuity of the Mt. Ortles cores over millennia, it can be argued that this behaviour has been unprecedented at this location since the Northern Hemisphere Climatic Optimum.

Short summary
New ice cores were extracted from Alto dell'Ortles, the highest glacier of South Tyrol in the Italian Alps, to check whether prehistoric ice, which is coeval to the famous 5300-yr-old Tyrolean Iceman, is still preserved in this region. Dating of the ice cores confirms the hypothesis and indicates the drilling site has been glaciated since the end of the Northern Hemisphere Climatic Optimum (7000 yrs BP). We also infer that an unprecedented acceleration of the glacier flow has recently begun.