scholarly journals A Mid-Holocene reindeer antler from Regstrup, Sjælland, Denmark

2021 ◽  
Vol 10 ◽  
Author(s):  
Ole Bennike ◽  
Theis Zetner Trolle Jensen ◽  
Alberto John Taurozzi ◽  
Meaghan Mackie ◽  
Lone Claudi-Hansen ◽  
...  
Keyword(s):  
The Holocene ◽  
Summer Temperatures

A small, shed antler fragment of a reindeer from Sjælland, Denmark has been dated to the Mid-Holocene, ca., 4700 cal B.C. Reindeer was an important component of the Lateglacial fauna in Denmark, and the species survived for ca. 1400 years into the Holocene. However, we consider it highly unlikely that this species inhabited Denmark during the Mid-Holocene, when dense forests characterized the vegetation and summer temperatures were somewhat higher than at present. We suggest that the reindeer antler came to Sjælland from Norway or Sweden as a result of trade, perhaps involving flint.

When Did Vesicular Av Horizons Form in the Desert SW U.S.: Elucidating Between Soil Processes and Luminescence Ages

2020 ◽  
Author(s):  
Eric McDonald ◽  
Mark Sweeney ◽  
Paul Hanson ◽  
Brad Sion
Keyword(s):  
Sea Level ◽  
Sonoran Desert ◽  
Mojave Desert ◽  
Soil Profiles ◽  
Soil Morphology ◽  
Desert Soils ◽  
The Holocene ◽  
Soil Mixing ◽  
Soil Temperatures ◽  
Summer Temperatures

<p>Vesicular A (Av) horizons, and associated overlying desert (rock) pavement, are ubiquitous features across desert environments.  Extensive research has demonstrated that the Av horizons develop from the incorporation of dust (eolian sediment) during soil development; however, two conflicting models have emerged regarding the age of the Av horizons.  Published luminescence (OSL) ages from Av horizons suggest that Av horizons are Holocene, with reported ages commonly ≤5 ka.  In addition, other studies have suggested Av horizons and desert pavements are Holocene in age because Late Pleistocene environmental conditions (primarily an increase in vegetation cover) largely destroyed desert pavements and Av horizons prior to the Holocene, especially for surfaces above 300-400 m elevation.  In contrast, time-related trends in the morphology of Av horizons suggest that Av horizons and pavements must have existed prior to the Holocene. </p><p>Geochronology and soil morphology from two soil chronosequences formed on alluvial fans in the Mojave Desert (soils ~0.5 ka to ~100 ka, ~900 m above sea level) and in the Sonoran Desert (soils ~0.5 ka to ~250 ka; ~200 m above sea level) indicate that Av horizons existed prior to the Holocene and that the strength of Av development coincides with increasing age of the surface.  In both chronosequences, Av horizon properties of eolian derived silt and clay, development of soil structure, horizon thickness, all systematically increase with surface age on soils with no evidence of past erosion or substantial soil mixing.  Soil morphology and depth profile relations further support that soil profiles are intact with no evidence of erosion or mixing just prior to the Holocene.  OSL dates of Av horizons are considerably younger than soil profiles dated with cosmogenic nuclides and OSL.  Some examples include:  Av: 5ka/soil: 10-12ka; Av: 1-3ka/soil: 16-21ka; Av: 2-6ka/soil: 50-60ka; Av: 1ka/soil: 210 ka.  Mixing of the Av and episodic addition of Holocene dust cannot alone account for age inconsistencies. Recent research using OSL for thermochronology indicates that closure of electron traps occurs between 35<sup>o</sup> to 50<sup>o </sup>C.  Measured hourly summer temperatures in Av horizons (Sonoran and Mojave Desert sites) commonly exceed 35<sup> o</sup> to 50<sup>o</sup>C May through September.  We suggest that anomalously young ages for Av horizons may be due to high soil temperatures and degradation of the OSL system.</p>

Paleoceanographic changes in the Disko Bugt area, West Greenland, during the Holocene

The Holocene ◽  
2014 ◽  
Vol 24 (11) ◽  
pp. 1573-1583 ◽  
Author(s):  
Marie-Michèle Ouellet-Bernier ◽  
Anne de Vernal ◽  
Claude Hillaire-Marcel ◽  
Matthias Moros
Keyword(s):  
Greenland Ice Sheet ◽  
Sea Surface ◽  
Benthic Foraminifers ◽  
The Holocene ◽  
West Greenland ◽  
West Greenland Current ◽  
Isotopic Analyses ◽  
Modern Analogue ◽  
Summer Temperatures ◽  
Harsh Conditions

Micropaleontological analyses of a sediment core raised in Disko Bugt (West of Greenland) were undertaken in order to document paleoceanographical changes in the eastern Baffin Bay during the Holocene. The modern analogue technique (MAT) applied to dinocyst assemblages provided information on paleo-sea-surface conditions, whereas isotopic analyses of benthic foraminifers aimed at documenting the ‘deep’ water mass occupying the site. During the earlier interval recorded (~10 to ~7.3 cal. kyr BP), important discharge of ice and meltwater from the Greenland Ice Sheet (GIS) margin, notably through the Jakobshavn Isbrae, resulted in harsh conditions with a dense sea-ice cover and low temperatures, productivity, and foraminiferal abundances. Postglacial conditions settled at ~7.3 cal. kyr BP, with a sharp rise in dinocyst abundance and species diversity, which led to reconstruct increase in summer temperatures. We link this transition to the advection of West Greenland Current waters in the upper part of the water column after the reduction of meltwater inputs from GIS. Optimal temperature conditions reaching up to >10°C were finally achieved in surface waters at ~6 cal. kyr BP. Slight cooling pulses were then recorded at ~4.2–4 and ~1.5–1 cal. kyr BP, and the final optimum recorded in surface temperature from ~1 to 0.8 cal. kyr BP is associated with the ‘Medieval Warm Period’. Throughout the postglacial interval, the data suggest an opposition between sea-surface temperatures and salinity, with warmer intervals being characterized by lower salinity waters, probably as a result of the higher freshwater discharge along the ice margin and notably the Jakobshavn Isbrae.

scholarly journals Glacier response to Holocene warmth inferred from in situ <sup>10</sup>Be and <sup>14</sup>C bedrock analyses in Steingletscher's forefield (central Swiss Alps)

2022 ◽  
Vol 18 (1) ◽  
pp. 23-44
Author(s):  
Irene Schimmelpfennig ◽  
Joerg M. Schaefer ◽  
Jennifer Lamp ◽  
Vincent Godard ◽  
Roseanne Schwartz ◽  
...  
Keyword(s):  
Swiss Alps ◽  
Ice Age ◽  
European Alps ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Mountain Glaciers ◽  
Driving Mechanisms ◽  
Summer Temperatures ◽  
The Alps

Abstract. Mid-latitude mountain glaciers are sensitive to local summer temperature changes. Chronologies of past glacier fluctuations based on the investigation of glacial landforms therefore allow for a better understanding of natural climate variability at local scale, which is relevant for the assessment of the ongoing anthropogenic climate warming. In this study, we focus on the Holocene, the current interglacial of the last 11 700 years, which remains a matter of dispute regarding its temperature evolution and underlying driving mechanisms. In particular, the nature and significance of the transition from the early to mid-Holocene and of the Holocene Thermal Maximum (HTM) are still debated. Here, we apply an emerging approach by combining in situ cosmogenic 10Be moraine and 10Be–14C bedrock dating from the same site, the forefield of Steingletscher (European Alps), and reconstruct the glacier's millennial recession and advance periods. The results suggest that, subsequent to the final deglaciation at ∼10 ka, the glacier was similar to or smaller than its 2000 CE extent for ∼7 kyr. At ∼3 ka, Steingletscher advanced to an extent slightly outside the maximum Little Ice Age (LIA) position and until the 19th century experienced sizes that were mainly confined between the LIA and 2000 CE extents. These findings agree with existing Holocene glacier chronologies and proxy records of summer temperatures in the Alps, suggesting that glaciers throughout the region were similar to or even smaller than their 2000 CE extent for most of the early and mid-Holocene. Although glaciers in the Alps are currently far from equilibrium with the accelerating anthropogenic warming, thus hindering a simple comparison of summer temperatures associated with modern and paleo-glacier sizes, our findings imply that the summer temperatures during most of the Holocene, including the HTM, were similar to those at the end of the 20th century. Further investigations are necessary to refine the magnitude of warming and the potential HTM seasonality.

The Tyrolean Iceman and His Glacial Environment During the Holocene

Radiocarbon ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 395-405 ◽  
Author(s):  
Walter Kutschera ◽  
Gernot Patzelt ◽  
Peter Steier ◽  
Eva Maria Wild
Keyword(s):  
Little Ice Age ◽  
Present Knowledge ◽  
Ice Age ◽  
European Alps ◽  
Tree Line ◽  
Human Influence ◽  
Temperature Variations ◽  
The Holocene ◽  
Summer Temperatures ◽  
Tyrolean Iceman

AbstractThis paper summarizes the present knowledge on the variation of summer temperatures in the European Alps throughout the Holocene by combining the results of an extraordinary archaeological find with the information gathered from glacier and tree-line movements. As it turns out, there were several distinct periods were the glaciers were smaller than today, allowing in some periods the growth of trees in areas, which even now are still covered with ice. On average, the first half of the Holocene was warmer than the second half, with temperatures starting to decrease around the time of the Iceman some 5000 yr ago. One of the coldest periods during the Holocene, the so-called Little Ice Age (LIA), lasted from about AD 1300 to 1850. It is well known that since then the Alpine glaciers have been receding, most likely amplified by anthropogenic impact. The study of temperature variations before human influence may help to eventually disentangle natural and anthropogenic causes for the global warming of our time.

Late Quaternary Vegetation and Early Holocene Quantitative Climate Estimates from Morwell Swamp, Latrobe Valley, South-eastern Australia

1997 ◽  
Vol 45 (3) ◽  
pp. 549 ◽  
Author(s):  
P. J. Lloyd ◽  
A. P. Kershaw
Keyword(s):  
Late Quaternary ◽  
Early Holocene ◽  
Pollen Diagram ◽  
The Holocene ◽  
Brasenia Schreberi ◽  
South Eastern ◽  
Eastern Australia ◽  
Summer Temperatures ◽  
Vegetation And Climate ◽  
South Eastern Australia

A pollen diagram from Morwell Swamp provides a record of vegetation and climate through the Holocene period while the application of a bioclimatic analysis of the aquatic species Brasenia schreberi to the occurrence of its pollen in the record allows the first quantitative reconstruction of early Holocene climate from mainland south-eastern Australia. The beginning of the Holocene, c. 10000 years before present (BP), was marked by the establishment of permanent water within the basin and an expansion of forest under conditions of increasing precipitation and probably also temperature. The early Holocene forests were dominated by Casuarinaceae, a situation typical of lowland south-eastern Australia. The presence of Brasenia schreberi Gmel., a species now restricted to lower latitudes, suggests that, by c. 9000 years BP, mean annual temperatures had risen to slighly above today’s values, while summer temperatures may have been at least 1.3˚C higher. These results are surprising considering that most previous evidence has suggested that optimal climatic conditions were achieved between about 7000 and 5000 years ago, and that radiation levels are predicted, from Milankovitch forcing, to have been lower than today at this time in the Southern Hemisphere. It is clearly necessary to be somewhat cautious about the wholescale acceptance of the quantitative values at this stage, although they are not contradicted by other palynological data. Subsequent regional increases in the wetter forest elements, Nothofagus and Pomaderris, indicate a middle Holocene peak in precipitation, although it is estimated, from a bioclimatic analysis of Nothofagus, that summer temperatures had become substantially lower than today. This lowering may have been due to a local or regional increase in cloud cover. There is evidence for minor variation in vegetation and climate within the late Holocene, which is consistent with evidence from elsewhere within the region.

Holocene tree line, permafrost, and climate dynamics in the Nenets Region, East European Arctic

2004 ◽  
Vol 41 (10) ◽  
pp. 1141-1158 ◽  
Author(s):  
Seija Kultti ◽  
Pirita Oksanen ◽  
Minna Väliranta
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
The Arctic ◽  
Tree Line ◽  
The Holocene ◽  
East European ◽  
Summer Temperatures ◽  
European Arctic ◽  
Peat Profile ◽  
Lake Core

Pollen, stomata, and macrofossils in a lake core with a basal date of 9700 14C BP were used to reconstruct past changes in climate and vegetation in the arctic tree line area, northeast European Russia. A palsa peat profile was investigated to establish a chronology of mire initiation and permafrost development during the Holocene. Macrofossils show that tree birch was present in the study area at the beginning of the Holocene and stands of spruce became established shortly thereafter. However, pollen evidence suggests that almost 400 years passed before the area was occupied by a mixed spruce–birch forest, which lasted until ca. 5000 BP. Subsequently, the area reverted to forest–tundra. Paludification began ca. 9000 BP continuing at least until 5700 BP. The conditions were permafrost-free at least until 4500 BP. The latest permafrost aggradation phase is dated to the Little Ice Age. We interpret summer temperatures to have been ca. 3–4 °C higher between ca. 8900 and 5500 BP than at present, and the lowest temperature regime of the Holocene to have occurred between 2700 and 2100 BP.

Isotopic Evidence of Holocene Climatic Change in the San Juan Mountains, Colorado

1988 ◽  
Vol 30 (3) ◽  
pp. 350-353 ◽  
Author(s):  
Irving Friedman ◽  
Paul Carrara ◽  
Jim Gleason
Keyword(s):  
Climatic Change ◽  
Major Change ◽  
San Juan ◽  
Tree Line ◽  
The Holocene ◽  
Isotopic Evidence ◽  
San Juan Mountains ◽  
Summer Temperatures

The δD of cellulose from 14C-dated wood, collected in the San Juan Mountains of southwestern Colorado, decreased by about 45‰ from 9600 to 3100 yr B.P. and an additional 25‰ to the present. The wood samples are from trees that grew above present-day tree line and reflect a time of warmer average summer temperatures. These changes in δD are interpreted to indicate a major change during the Holocene in the sources of moisture, in the seasonality of precipitation, or in both.

The Holocene thermal maximum and late-Holocene cooling in the tundra of NE European Russia

2011 ◽  
Vol 75 (3) ◽  
pp. 501-511 ◽  
Author(s):  
J. Sakari Salonen ◽  
Heikki Seppä ◽  
Minna Väliranta ◽  
Vivienne J. Jones ◽  
Angela Self ◽  
...  
Keyword(s):  
Late Holocene ◽  
Temperature Drop ◽  
Plant Macrofossils ◽  
European Russia ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Northern European ◽  
Thermal Maximum ◽  
Summer Temperatures ◽  
Northern European Russia

AbstractTo investigate the Holocene climate and treeline dynamics in the European Russian Arctic, we analysed sediment pollen, conifer stomata, and plant macrofossils from Lake Kharinei, a tundra lake near the treeline in the Pechora area. We present quantitative summer temperature reconstructions from Lake Kharinei and Lake Tumbulovaty, a previously studied lake in the same region, using a pollen–climate transfer function based on a new calibration set from northern European Russia. Our records suggest that the early-Holocene summer temperatures from 11,500 cal yr BP onwards were already slightly higher than at present, followed by a stable Holocene Thermal Maximum (HTM) at 8000–3500 cal yr BP when summer temperatures in the tundra were ca. 3°C above present-day values. A Picea forest surrounded Lake Kharinei during the HTM, reaching 150 km north of the present taiga limit. The HTM ended with a temperature drop at 3500–2500 cal yr BP associated with permafrost initiation in the region. Mixed spruce forest began to disappear around Lake Kharinei at ca. 3500 cal yr BP, with the last tree macrofossils recorded at ca. 2500 cal yr BP, suggesting that the present wide tundra zone in the Pechora region formed during the last ca. 3500 yr.

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