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Steven Mithen - One of the best experts on this subject based on the ideXlab platform.
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seasonal temperature variability of the Neoglacial 3300 2500 bp and roman warm period 2500 1600 bp reconstructed from oxygen isotope ratios of limpet shells patella vulgata northwest scotland
Palaeogeography Palaeoclimatology Palaeoecology, 2012Co-Authors: Ting Wang, Donna Surge, Steven MithenAbstract:Abstract Seasonal sea-surface temperature variability for the Neoglacial (3300–2500 BP) and Roman Warm Period (RWP; 2500–1600 BP), which correspond to the Bronze and Iron Ages, respectively, was estimated using oxygen isotope ratios obtained from high-resolution samples micromilled from radiocarbon-dated, archaeological limpet (Patella vulgata) shells. The coldest winter months recorded in Neoglacial shells averaged 6.6 ± 0.3 °C, and the warmest summer months averaged 14.7 ± 0.4 °C. One Neoglacial shell captured a year without a summer, which may have resulted from a dust veil from a volcanic eruption in the Katla volcanic system in Iceland. RWP shells record average winter and summer monthly temperatures of 6.3 ± 0.1 °C and 13.3 ± 0.3 °C, respectively. These results capture a cooling transition from the Neoglacial to RWP, which is further supported by earlier studies of pine history in Scotland, pollen type analyses in northeast Scotland, and European glacial events. The cooling transition observed at the boundary between the Neoglacial and RWP in our study also agrees with the abrupt climate deterioration at 2800–2700 BP (also referred to as the Subboreal/Subatlantic transition) and therefore may have been driven by decreased solar radiation and weakened North Atlantic Oscillation conditions.
Bart Van De Vijver - One of the best experts on this subject based on the ideXlab platform.
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Timing of the Neoglacial onset on the North-Eastern Antarctic Peninsula based on lacustrine archive from Lake Anónima, Vega Island
Global and Planetary Change, 2020Co-Authors: Tomáš Čejka, Daniel Nývlt, Kateřina Kopalová, Marie Bulínová, Jan Kavan, Juan M. Lirio, Silvia H. Coria, Bart Van De VijverAbstract:Abstract To understand the complexity of the climate patterns in the Holocene, it is necessary to build detailed chronologies that provide a holistic picture of the individual climate periods occurring in the polar regions. In this regard, here we present a completely new, 14C-dated and synchronised multi-proxy chronology from the Lake Anonima (Vega Island, north-eastern Antarctic Peninsula) that provides a unique insight into the Late Holocene environment. In particular, we aim to interpret the substantial environmental and climatic change between the mid-late Holocene Hypsithermal and Neoglacial periods using various geochemical (total organic carbon, X-ray fluorescence spectroscopy), petrophysical (magnetic susceptibility, laser granulometry) and biological (diatom biostratigraphy) proxies. The termination of the mid-late Holocene Hypsithermal, characterised by overall warmer climate with favourable conditions for biogenic productivity, is followed by the regional-scale Neoglacial period, distinctive by the onset of climate deterioration, decreased siliciclastic input, suppressed biogenic (diatom) productivity and low organic content. Based on a principal component analysis, a multi-proxy record provides the precise timing of the Neoglacial onset in the Lake Anonima record at 2050 (2σ: 1990–2130) cal. yrs BP. Applying an adjacent and correlative ice-core (James Ross Island ice cap, r = 0.42), as well as a composite lake sediment (Beak Island, r = 0.49) chronologies, our research provides a refined timing of the Neoglacial onset for the north-eastern Antarctic Peninsula, which is determined to be 2070 ± 50 yrs. BP. Moreover, the Neoglacial onset was compared with other studies from respective parts of the Antarctic Peninsula.
Philip Deline - One of the best experts on this subject based on the ideXlab platform.
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Be-10 exposure dating of the timing of Neoglacial glacier advances in the Ecrins-Pelvoux massif, southern French Alps
Quaternary Science Reviews, 2017Co-Authors: Melaine Le Roy, Philip Deline, Julien Carcaillet, Irene Schimmelpfennig, Magali Ermini, Georges Aumaitre, D.l. Bourles, Karim KeddadoucheAbstract:Alpine glacier variations are known to be reliable proxies of Holocene climate. Here, we present a terrestrial cosmogenic nuclide (TCN)-based glacier chronology relying on 24 new Be-10 exposure ages, which constrain maximum Neoglacial positions of four small to mid-sized glaciers (Rateau, Lautaret, Bonnepierre and Etages) in the Ecrins-Pelvoux massif, southern French Alps. Glacier advances, marked by (mainly lateral) moraine ridges that are located slightly outboard of the Little Ice Age (LIA, c. 1250-1860 AD) maximum positions, were dated to 4.25 +/- 0.44 ka, 3.66 +/- 0.09 ka, 2.09 +/- 0.10 ka, c. 1.31 +/- 0.17 ka and to 0.92 +/- 0.02 ka. The `4.2 ka advance, albeit constrained by rather scattered dates, is to our knowledge exposure-dated here for the first time in the Alps. It is considered as one of the first major Neoglacial advance in the western Alps, in agreement with other regional paleoclimatological proxies. We further review Alpine and Northern Hemisphere mid-to-high latitude evidence for climate change and glacier activity concomitant with the `4.2 ka event. The `2.1 ka advance was not extensively dated in the Alps and is thought to represent a prominent advance in early Roman times. Other Neoglacial advances dated here match the timing of previously described Alpine Neoglacial events. Our results also suggest that a Neoglacial maximum occurred at Etages Glacier 0.9 ka ago, i.e. during the Medieval Climate Anomaly (MCA, c. 850-1250 AD). At Rateau Glacier, discordant results are thought to reflect exhumation and snow cover of the shortest moraine boulders. Overall, this study highlights the need to combine several sites to develop robust Neoglacial glacier chronologies in order to take into account the variability in moraine deposition pattern and landform obliteration and conservation.
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calendar dated glacier variations in the western european alps during the Neoglacial the mer de glace record mont blanc massif
Quaternary Science Reviews, 2015Co-Authors: Melaine Le Roy, Philip Deline, Kurt Nicolussi, Laurent Astrade, Jeanlouis Edouard, Cecile Miramont, Fabien ArnaudAbstract:Holocene glacier records from the western European Alps are still sparse, although a number of sites are well suited to constraining pre- and early- Little Ice Age (LIA) glacier advances. The present study provides the first dendrochronologically-based and calendar-dated Neoglacial glacier chronology for the Mont Blanc massif, French Alps. It is based on the analysis of over 240 glacially buried Pinus cembra subfossil logs and wood remains found either embedded-in-till or as detrital material in the Mer de Glace right lateral moraine. Only a few of the samples were found to be ‘formally in situ’ but we show that some logs were ‘virtually in situ’ (not rooted but showing little or no evidence of reworking) and could be used to accurately reconstruct past glacier margin behavior in space and time. Uncertainties regarding the other samples may relate to original growth location and/or to outer wood decay. The resulting dates (followed by a ‘+’) were therefore considered maximum-limiting ages for glacier advances. The main burial events – interpreted as glacier advances – occurred between ca 1655+ and 1544+ BC, between ca 1230+ and 1105+ BC, between ca 1013+ and 962+/937+ BC, at ca 802–777 BC, after 608+ BC, between 312 and 337 AD, between ca 485+ AD and 606+ AD, between 1120 and 1178 AD, between ca 1248 and 1278+/1296 AD, and after 1352+ AD. These advances predate the late LIA maxima known from historical sources. The magnitude of the advances gradually increased to culminate in three near-Neoglacial maxima during the 7th, 12th and 13th centuries AD, followed by a first LIA/Neoglacial maximum in the second half of the 14th century AD. The pattern of Neoglacial events described here is coherent with Central and Eastern Alpine glacier chronologies. This indicates marked synchronicity of late Holocene glacier variability and forcing at a regional scale, although occasional differences could be detected between ‘Western’ and ‘Eastern’ records. The Mer de Glace record also confirms the link between the timing of sediment erosion in a high-elevation glaciated Alpine catchment and subsequent deposition in the sub-alpine Lake Bourget.
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10Be exposure dating of onset and timing of Neoglacial glacier advances in the Ecrins massif, French Alps.
2013Co-Authors: Melaine Le Roy, Philip Deline, Julien CarcailletAbstract:Alpine glaciers are known to be highly sensitive to change in temperature and precipitation on decadal to centennial time scales. For two decades, numerous studies on Holocene climate revealed a period marked by abrupt cold reversals (e.g. 8.2 ka event) with increasing frequency and magnitude after the Holocene Climatic Optimum, during the so-called Neoglacial period (roughly the last 4 ka). State-of-the-art studies indicate that largest alpine glaciers failed to exceed their Little Ice Age (LIA) extent during these LIA Type-Events, unlike certain smaller glaciers. In the French Alps, very few investigations were conducted to date on Holocene glacier variability. Almost all studies focused on the most glacierized area: the Mont Blanc massif, where suitable organic remains to apply radiocarbon dating and dendrochronology are available. Other glacierized massifs are poorly studied, without any Holocene/Neoglacial glacier chronology up to now. Here, we present the results of a study focusing on six glacier forefields distributed in the Ecrins massif. Detailed geomorphological mapping and in-situ produced 10Be dating were carried on multi-crested so-called "LIA composite moraines". The targeted ridges are located in distal position with respect to late LIA drift in order to identify Holocene cold pulses that have led to (or slightly exceeded) LIA-like glacier extent. The 35 10Be ages obtained revealed that the onset of Neoglacial occurred at ~4.2 ka, and that at least two other advances were recorded at ~3.3 ka and ~0.85 ka. One site has yielded a nearly complete Neoglacial record as four discrete events have been dated. These results highlight the potential of lateral moraine ridge stratigraphy which could yield accurate record when sufficiently preserved, but also the different preservation of landforms along the glacier margin which could censor the record.
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glacier fluctuations in the western alps during the Neoglacial as indicated by the miage morainic amphitheatre mont blanc massif italy
Boreas, 2005Co-Authors: Philip Deline, G OrombelliAbstract:Holocene glacier variations pre-dating the Little Ice Age are poorly known in the western Alps. Studied for two centuries, the Miage morainic amphitheatre (MMA) is composed of three subconcentric sets of c. 25 moraines. Because of its location and of a dominant mode of morainic accretion, the MMA is a well-preserved marker of the glacier dynamics during the Neoglacial. Radiocarbon dates were obtained by digging and coring in intermorainic depressions of the MMA and through a deep core drilling in a dammed-lake infill (Combal); complementary data for the inner MMA were obtained by lichenometry and dendrochronology. Radiocarbon chronology shows that (i) the MMA not only pre-dates the Little Ice Age (LIA), but was built at least since 5029–4648 cal. yr BP (beginning of the Neoglacial); (ii) outer sets of moraines pre-date 2748–2362 cal. yr BP; (iii) the MMA dammed the Lake Combal from 4.8 to 1.5 cal. kyr BP, while lakes/ponds formed inside the moraines (e.g. from 2147–1928 to 1506–1295 cal. yr BP). The ‘Neoglacial model’ proposed here considers that the MMA formed during the whole Neoglacial by a succession of glacier advances at 4.8–4.6 cal. ky BP (early
Lauren M. Simkins - One of the best experts on this subject based on the ideXlab platform.
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Timing of the most recent Neoglacial advance and retreat in the South Shetland Islands, Antarctic Peninsula: insights from raised beaches and Holocene uplift rates
Quaternary Science Reviews, 2012Co-Authors: Alexander R. Simms, Erik R. Ivins, Regina Dewitt, Peter Kouremenos, Lauren M. SimkinsAbstract:Abstract The timing of the most recent Neoglacial advance in the Antarctic Peninsula is important for establishing global climate teleconnections and providing important post-glacial rebound corrections to gravity-based satellite measurements of ice loss. However, obtaining accurate ages from terrestrial geomorphic and sedimentary indicators of the most recent Neoglacial advance in Antarctica has been hampered by the lack of historical records and the difficulty of dating materials in Antarctica. Here we use a new approach to dating flights of raised beaches in the South Shetland Islands of the northern Antarctic Peninsula to bracket the age of a Neoglacial advance that occurred between 1500 and 1700 AD, broadly synchronous with compilations for the timing of the Little Ice Age in the northern hemisphere. Our approach is based on optically stimulated luminescence of the underside of buried cobbles to obtain the age of beaches previously shown to have been deposited immediately inside and outside the moraines of the most recent Neoglacial advance. In addition, these beaches mark the timing of an apparent change in the rate of isostatic rebound thought to be in response to the same glacial advance within the South Shetland Islands. We use a Maxwell viscoelastic model of glacial-isostatic adjustment (GIA) to determine whether the rates of uplift calculated from the raised beaches are realistic given the limited constraints on the ice advance during this most recent Neoglacial advance. Our rebound model suggests that the subsequent melting of an additional 16–22% increase in the volume of ice within the South Shetland Islands would result in a subsequent uplift rate of 12.5 mm/yr that lasted until 1840 AD resulting in a cumulative uplift of 2.5 m. This uplift rate and magnitude are in close agreement with observed rates and magnitudes calculated from the raised beaches since the most recent Neoglacial advance along the South Shetland Islands and falls within the range of uplift rates from similar settings such as Alaska.
Benjamin J C Laabs - One of the best experts on this subject based on the ideXlab platform.
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a lacustrine based Neoglacial record for glacier national park montana usa
Quaternary Science Reviews, 2012Co-Authors: Jeffrey S Munroe, Thomas Crocker, Alena Giesche, Lukas E Rahlson, Logan T Duran, Matthew F Bigl, Benjamin J C LaabsAbstract:Abstract Multi-proxy study of sediment cores retrieved from lakes below modern glaciers supports the first detailed Neoglacial chronology for Glacier National Park (GNP), Montana. Analysis focused on sedimentary properties sensitive to the extent and activity of upstream glacier ice, including: water, organic matter, carbonate, and biogenic silica content; bulk density; mass accumulation rate; phosphorus fractionation; magnetic susceptibility; L*a*b* color values; and grain size distribution. Results indicate that alpine glaciers in GNP advanced and retreated numerous times during the Holocene after the onset of Neoglaciation ca 6500 BP. The two oldest phases of glacier expansion were synchronous with the well-documented Garibaldi (5600–6900 BP) and Tiedemann-Peyto (1900–3700 BP) phases in western Canada. Younger phases correspond with the First Millennium Advance in western Canada, as well as glacier with advances in the Sierra Nevada. The culminating Little Ice Age (LIA) advance was the most recent and extensive of a series of advance/retreat cycles over the past millennium. Retreat from the LIA maximum was the most dramatic episode of ice retreat in at least the last 1000 years.
