Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps

<p>Glaciers preserve climate variations in their geological and geomorphological records, which makes them prime candidates for climate reconstructions. Investigating the glacier–climate system over the past millennia is particularly relevant first because the amplitude and frequency of natura...

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Autores principales:	S. M. Braumann, J. M. Schaefer, S. M. Neuhuber, C. Lüthgens, A. J. Hidy, M. Fiebig
Formato:	article
Lenguaje:	EN
Publicado:	Copernicus Publications 2021
Materias:	Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350
Acceso en línea:	https://doaj.org/article/8938fb37ed7345e29ad4dd4ad51add7a
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spelling	oai:doaj.org-article:8938fb37ed7345e29ad4dd4ad51add7a2021-12-02T09:53:18ZEarly Holocene cold snaps and their expression in the moraine record of the eastern European Alps10.5194/cp-17-2451-20211814-93241814-9332https://doaj.org/article/8938fb37ed7345e29ad4dd4ad51add7a2021-12-01T00:00:00Zhttps://cp.copernicus.org/articles/17/2451/2021/cp-17-2451-2021.pdfhttps://doaj.org/toc/1814-9324https://doaj.org/toc/1814-9332<p>Glaciers preserve climate variations in their geological and geomorphological records, which makes them prime candidates for climate reconstructions. Investigating the glacier–climate system over the past millennia is particularly relevant first because the amplitude and frequency of natural climate variability during the Holocene provides the climatic context against which modern, human-induced climate change must be assessed. Second, the transition from the last glacial to the current interglacial promises important insights into the climate system during warming, which is of particular interest with respect to ongoing climate change.</p> <p>Evidence of stable ice margin positions that record cooling during the past 12 kyr are preserved in two glaciated valleys of the Silvretta Massif in the eastern European Alps, the Jamtal (JAM) and the Laraintal (LAR). We mapped and dated moraines in these catchments including historical ridges using beryllium-10 surface exposure dating (<span class="inline-formula"><sup>10</sup></span>Be SED) techniques and correlate resulting moraine formation intervals with climate proxy records to evaluate the spatial and temporal scale of these cold phases. The new geochronologies indicate the formation of moraines during the early Holocene (EH), ca. 11.0 <span class="inline-formula">±</span> 0.7 ka (<span class="inline-formula"><i>n</i></span> <span class="inline-formula">=</span> 19). Boulder ages along historical moraines (<span class="inline-formula"><i>n</i></span> <span class="inline-formula">=</span> 6) suggest at least two glacier advances during the Little Ice Age (LIA; ca. 1250–1850 CE) around 1300 CE and in the second half of the 18th century. An earlier advance to the same position may have occurred around 500 CE.</p> <p>The Jamtal and Laraintal moraine chronologies provide evidence that millennial-scale EH warming was superimposed by centennial-scale cooling. The timing of EH moraine formation coincides with brief temperature drops identified in local and regional paleoproxy records, most prominently with the Preboreal Oscillation (PBO) and is consistent with moraine deposition in other catchments in the European Alps and in the Arctic region. This consistency points to cooling beyond the local scale and therefore a regional or even hemispheric climate driver. Freshwater input sourced from the Laurentide Ice Sheet (LIS), which changed circulation patterns in the North Atlantic, is a plausible explanation for EH cooling and moraine formation in the Nordic region and in Europe.</p>S. M. BraumannS. M. BraumannJ. M. SchaeferS. M. NeuhuberC. LüthgensA. J. HidyM. FiebigCopernicus PublicationsarticleEnvironmental pollutionTD172-193.5Environmental protectionTD169-171.8Environmental sciencesGE1-350ENClimate of the Past, Vol 17, Pp 2451-2479 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350
spellingShingle	Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 S. M. Braumann S. M. Braumann J. M. Schaefer S. M. Neuhuber C. Lüthgens A. J. Hidy M. Fiebig Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps
description	<p>Glaciers preserve climate variations in their geological and geomorphological records, which makes them prime candidates for climate reconstructions. Investigating the glacier–climate system over the past millennia is particularly relevant first because the amplitude and frequency of natural climate variability during the Holocene provides the climatic context against which modern, human-induced climate change must be assessed. Second, the transition from the last glacial to the current interglacial promises important insights into the climate system during warming, which is of particular interest with respect to ongoing climate change.</p> <p>Evidence of stable ice margin positions that record cooling during the past 12 kyr are preserved in two glaciated valleys of the Silvretta Massif in the eastern European Alps, the Jamtal (JAM) and the Laraintal (LAR). We mapped and dated moraines in these catchments including historical ridges using beryllium-10 surface exposure dating (<span class="inline-formula"><sup>10</sup></span>Be SED) techniques and correlate resulting moraine formation intervals with climate proxy records to evaluate the spatial and temporal scale of these cold phases. The new geochronologies indicate the formation of moraines during the early Holocene (EH), ca. 11.0 <span class="inline-formula">±</span> 0.7 ka (<span class="inline-formula"><i>n</i></span> <span class="inline-formula">=</span> 19). Boulder ages along historical moraines (<span class="inline-formula"><i>n</i></span> <span class="inline-formula">=</span> 6) suggest at least two glacier advances during the Little Ice Age (LIA; ca. 1250–1850 CE) around 1300 CE and in the second half of the 18th century. An earlier advance to the same position may have occurred around 500 CE.</p> <p>The Jamtal and Laraintal moraine chronologies provide evidence that millennial-scale EH warming was superimposed by centennial-scale cooling. The timing of EH moraine formation coincides with brief temperature drops identified in local and regional paleoproxy records, most prominently with the Preboreal Oscillation (PBO) and is consistent with moraine deposition in other catchments in the European Alps and in the Arctic region. This consistency points to cooling beyond the local scale and therefore a regional or even hemispheric climate driver. Freshwater input sourced from the Laurentide Ice Sheet (LIS), which changed circulation patterns in the North Atlantic, is a plausible explanation for EH cooling and moraine formation in the Nordic region and in Europe.</p>
format	article
author	S. M. Braumann S. M. Braumann J. M. Schaefer S. M. Neuhuber C. Lüthgens A. J. Hidy M. Fiebig
author_facet	S. M. Braumann S. M. Braumann J. M. Schaefer S. M. Neuhuber C. Lüthgens A. J. Hidy M. Fiebig
author_sort	S. M. Braumann
title	Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps
title_short	Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps
title_full	Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps
title_fullStr	Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps
title_full_unstemmed	Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps
title_sort	early holocene cold snaps and their expression in the moraine record of the eastern european alps
publisher	Copernicus Publications
publishDate	2021
url	https://doaj.org/article/8938fb37ed7345e29ad4dd4ad51add7a
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Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps

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