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4 results on '"Be-10 surface exposure dating"'

1. Timing and dynamics of glaciation in the Ikh Turgen Mountains, Altai region, High Asia

Author

Blomdin, Robin, Stroeven, Arjen P., Harbor, Jonathan M., Gribenski, Natacha, Caffee, Marc W., Heyman, Jakob, Rogozhina, Irina, Ivanov, Mikhail N., Petrakov, Dmitry A., Walther, Michael, Rudoy, Alexei N., Zhang, Wei, Orkhonselenge, Alexander, Hättestrand, Clas, Lifton, Nathaniel A., Jansson, Krister N., Blomdin, Robin, Stroeven, Arjen P., Harbor, Jonathan M., Gribenski, Natacha, Caffee, Marc W., Heyman, Jakob, Rogozhina, Irina, Ivanov, Mikhail N., Petrakov, Dmitry A., Walther, Michael, Rudoy, Alexei N., Zhang, Wei, Orkhonselenge, Alexander, Hättestrand, Clas, Lifton, Nathaniel A., and Jansson, Krister N.

Abstract

Spanning the northern sector of High Asia, the Altai region contains a rich landform record of glaciation. We report the extent, chronologies, and dynamics of two paleoglaciers on opposite flanks of the Ikh Turgen mountains (In Russian: Chikhacheva Range), straddling the border between Russia and Mongolia, using a combination of remote sensing-based glacial geomorphological mapping, Be-10 surface exposure dating, and geomorphometric analysis. On the eastern side (Mongolia), the Turgen-Asgat paleoglacier, with its potential for developing a large accumulation area (similar to 257 km(2)), expanded 40 km down valley, and mean ages from a latero-frontal moraine indicate deglaciation during marine oxygen isotope stage (MIS) 3 (45.1 +/- 1.8 ka, n = 4) and MIS 2 (22.8 +/- 3.3 ka, n = 5). These minimum age constraints are consistent with other Be-10 glacial chronologies and paleoclimate records from the region, which indicates glacier culmination during cold and wet conditions coinciding with MIS 3 (piedmont-style glaciation; inferred for a few sites across the region) and glacier culmination during cold and dry conditions coinciding with MIS 2 (mainly valley-style glaciation; inferred from several sites across the region). On the western side (Russia), the Boguty paleoglacier had a smaller accumulation area (similar to 222 km(2)), and advanced 30 km down valley across a low gradient forefield. Surface exposure ages from two moraine complexes on this side of the mountains exhibit wide scatter (similar to 14-53 ka, n = 8), making paleoclimate inferences and comparison to other proxies difficult. Ice surface profile reconstructions imply that the two paleoglaciers likely shared an ice divide.

Published
2018
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2. Constraining the age of superimposed glacial records in mountain environments with multiple dating methods (Cantabrian Mountains, Iberian Peninsula)

Author

Jorge Sanjurjo, Vincent Rinterknecht, Sergio Llana-Fúnez, Laëtitia Léanni, Aster Team, María José Domínguez-Cuesta, Daniel Ballesteros, Laura Rodríguez-Rodríguez, Saúl González-Lemos, Montserrat Jiménez-Sánchez, Pablo Valenzuela, Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Panthéon-Sorbonne (UP1), Universidad de Oviedo [Oviedo], Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), University of A Coruña (UDC), Identités et Différenciation de l'Environnement des Espaces et des Sociétés (IDEES), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire Homme et Société (IRIHS), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Identité et Différenciation de l’Espace, de l’Environnement et des Sociétés (IDEES), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire Homme et Société (IRIHS), Normandie Université (NU)-Université de Caen Normandie (UNICAEN), Ministerio de Economia, Industria y Cornpetitividad - Gobierno de Espana, European Regional Development Fund through project CANDELA [CGL2012-31938], PCTI - Gobierno del Principado de Asturias (Spain), European Regional Development Fund (GEOCANTABRICA) [FC-15-GRUPIN14-044], INSU/CNRS, French MESR, CEA institute, Marie Curie-Clarin COFUND program by Gobierno del Principado de Asturias through FICYT, European Union/Marie Curie Actions [ACA-17-19], Normandie Université (NU)-Normandie Université (NU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Institut de Recherche Interdisciplinaire Homme et Société (IRIHS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Université Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Marine isotope stage, 010506 paleontology, Archeology, Cantabrian mountains, 010504 meteorology & atmospheric sciences, Pleistocene, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 01 natural sciences, Iberian peninsula, law.invention, [SHS]Humanities and Social Sciences, Be-10 surface exposure dating, Glaciation, law, luminescence, Radiocarbon dating, Glacial period, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Global and Planetary Change, geography, geography.geographical_feature_category, Last glacial maximum, Geology, Last Glacial Maximum, Glacier, Optically stimulated, Optically stimulated luminescence, Radiocarbon, Surface exposure dating, 13. Climate action, [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, Physical geography, Chronology
Abstract

International audience; Numerous cases of timing differences between glacier advances recorded in mountain environments have been documented over the last decade, usually suggesting potential age conflicts between the different dating techniques. The frequent use of a single technique to date numerically a given glacial sequence makes it difficult to address to what extent age differences can be an artifact related to biased numerical age results or a paleoclimate signature. Here we present a new set of 43 numerical ages based on three dating techniques -Be-10 surface exposure dating; radiocarbon; and optically stimulated luminescence-that complement the chronology of Pleistocene glacial advances in the Porma valley, in the central Cantabrian Mountains of Spain. Results compliment previous chronologies in the area, supporting an important glacial advance during Marine Isotope Stage 3 (Stage Ila: similar to 56 ka) that culminated with the Last Glacial Maximum advance (Stage llb: similar to 33-24 ka) of MIS 2 in response to increased rainfall and solar insolation minima. Glacier fronts reached elevations as low as 1130 m a.s.l. possibly without overriding evidence related to the previous Pleistocene glacial maximum extent. Glacier recession in the Cantabrian Mountains started at 21-20 ka ago, after the global LGM. We suggest that the recession was initiated by increased insolation followed by hyper-cool and dry conditions during Heinrich Stadial 1 in response to meltwater discharges in the North Atlantic.

Published
2018
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3. Evaluating the timing of former glacier expansions in the Tian Shan: A key step towards robust spatial correlations

Author

Blomdin, R., Stroeven, A., Harbor, J., Lifton, N., Heyman, J., Gribenski, N., Petrakov, D., Caffee, M., Ivanov, M., Hättestrand, C., Rogozhina, I., and Usubaliev, R.

Subjects
Global and Planetary Change, Geovetenskap och miljövetenskap, Tian Shan, Geology, Earth and Related Environmental Sciences, Glacial geomorphology, Paleoglaciation, Ecology, Evolution, Behavior and Systematics, Be-10 surface exposure dating
Abstract

The timing of past glaciation across the Tian Shan provides a proxy for past climate change in this critical area. Correlating glacial stages across the region is difficult but cosmogenic exposure ages have considerable potential. A drawback is the large observed scatter in Be-10 surface exposure data. To quantify the robustness of the dating, we compile, recalculate, and perform statistical analyses on sets of 10Be surface exposure ages from 25 moraines, consisting of 114 new and previously published ages. We assess boulder age scatter by dividing boulder groups into quality classes and rejecting boulder groups of poor quality. This allows us to distinguish and correlate robustly dated glacier limits, resulting in a more conservative chronology than advanced in previous publications. Our analysis shows that only one regional glacial stage can be reliably correlated across the Tian Shan, with glacier expansions occurring between 15 and 281 a during marine oxygen isotope stage (MIS) 2. However, there are examples of older more extensive indicators of glacial stages between MIS 3 and MIS 6. Paleoglacier extent during MIS 2 was mainly restricted to valley glaciation. Local deviations occur: in the central Kyrgyz Tian Shan paleoglaciers were more extensive and we propose that the topographic context explains this pattern. Correlation between glacial stages prior to late MIS 2 is less reliable, because of the low number of samples and/or the poor resolution of the dating. With the current resolution and spatial coverage of robustly-dated glacier limits we advise that paleoclimatic implications for the Tian Shan glacial chronology beyond MIS 2 are speculative and that continued work toward robust glacial chronologies is needed to resolve questions regarding drivers of past glaciation in the Tian Shan and Central Asia.

Published
2016
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4. Evaluating the timing of former glacier expansions in the Tian Shan : A key step towards robust spatial correlations

Author

Blomdin, Robin, Stroeven, Arjen P., Harbor, Jonathan M., Lifton, N. A., Heyman, J., Gribenski, Natacha, Petrakov, D. A., Caffee, M. W., Ivanov, M. N., Hättestrand, Clas, Rogozhina, I., Usubaliev, R., Blomdin, Robin, Stroeven, Arjen P., Harbor, Jonathan M., Lifton, N. A., Heyman, J., Gribenski, Natacha, Petrakov, D. A., Caffee, M. W., Ivanov, M. N., Hättestrand, Clas, Rogozhina, I., and Usubaliev, R.

Abstract

The timing of past glaciation across the Tian Shan provides a proxy for past climate change in this critical area. Correlating glacial stages across the region is difficult but cosmogenic exposure ages have considerable potential. A drawback is the large observed scatter in Be-10 surface exposure data. To quantify the robustness of the dating, we compile, recalculate, and perform statistical analyses on sets of 10Be surface exposure ages from 25 moraines, consisting of 114 new and previously published ages. We assess boulder age scatter by dividing boulder groups into quality classes and rejecting boulder groups of poor quality. This allows us to distinguish and correlate robustly dated glacier limits, resulting in a more conservative chronology than advanced in previous publications. Our analysis shows that only one regional glacial stage can be reliably correlated across the Tian Shan, with glacier expansions occurring between 15 and 281 a during marine oxygen isotope stage (MIS) 2. However, there are examples of older more extensive indicators of glacial stages between MIS 3 and MIS 6. Paleoglacier extent during MIS 2 was mainly restricted to valley glaciation. Local deviations occur: in the central Kyrgyz Tian Shan paleoglaciers were more extensive and we propose that the topographic context explains this pattern. Correlation between glacial stages prior to late MIS 2 is less reliable, because of the low number of samples and/or the poor resolution of the dating. With the current resolution and spatial coverage of robustly-dated glacier limits we advise that paleoclimatic implications for the Tian Shan glacial chronology beyond MIS 2 are speculative and that continued work toward robust glacial chronologies is needed to resolve questions regarding drivers of past glaciation in the Tian Shan and Central Asia.

Published
2016
Full Text
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