Ice Cores, Mountain Glaciers

2009 ◽  
pp. 457-463
Author(s):  
Lonnie G. Thompson
Keyword(s):  
Ice Cores ◽  
Mountain Glaciers

Constraining ice core chronologies with 39Ar and 81Kr

2021 ◽  
Author(s):  
Florian Ritterbusch ◽  
Jinho Ahn ◽  
Ji-Qiang Gu ◽  
Wei Jiang ◽  
Giyoon Lee ◽  
...  
Keyword(s):  
Sample Size ◽  
Half Life ◽  
Earth Science ◽  
Noble Gas ◽  
Ice Core ◽  
Ice Cores ◽  
High Mountain ◽  
National Academy Of Sciences ◽  
Geophysical Research ◽  
Mountain Glaciers

<p>Paleoclimate reconstructions from ice core records can be hampered due to the lack of a reliable chronology, especially when the stratigraphy is disturbed and conventional dating methods cannot be readily applied. The noble-gas radioisotopes <sup>81</sup>Kr and <sup>39</sup>Ar can in these cases provide robust constraints as they yield absolute, radiometric ages. <sup>81</sup>Kr (half-life 229 ka) covers the time span of 50-1300 ka, which is particularly relevant for polar ice cores, whereas <sup>39</sup>Ar (half-life 269 a) with a dating range of 50-1800 a is suitable for high mountain glaciers. For a long time the use of <sup>81</sup>Kr and <sup>39</sup>Ar for dating of ice samples was hampered by the lack of a detection technique that can meet its extremely small abundance at a reasonable sample size.</p><p>Here, we present <sup>81</sup>Kr and <sup>39</sup>Ar dating of Antarctic and Tibetan ice cores with the detection method Atom Trap Trace Analysis (ATTA), using 5-10 kg of ice for <sup>81</sup>Kr and 2-5 kg for <sup>39</sup>Ar. Recent advances in further decreasing the sample size and increasing the dating precision will be discussed. Current studies include <sup>81</sup>Kr dating in shallow ice cores from the Larsen Blue ice area, East Antarctica, in order to retrieve climate signals from the last glacial termination. Moreover, an <sup>39</sup>Ar profile from a central Tibetan ice core has been obtained in combination with layer counting based on isotopic and visual stratigraphic signals. The presented studies demonstrate how <sup>81</sup>Kr and <sup>39</sup>Ar can constrain the age range of ice cores and complement other methods in developing an ice core chronology.</p><p> </p><p>[1] Z.-T. Lu, Tracer applications of noble gas radionuclides in the geosciences, Earth-Science Reviews 138, 196-214, (2014)<br>[2] C. Buizert, Radiometric <sup>81</sup>Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica, Proceedings of the National Academy of Sciences, <strong>111</strong>, 6876, (2014)</p><p>[3] L. Tian, <sup>81</sup>Kr Dating at the Guliya Ice Cap, Tibetan Plateau, Geophysical Research Letters, (2019)</p><p>http://atta.ustc.edu.cn</p>

scholarly journals Mapping the suitability for ice-core drilling of glaciers in the European Alps and the Asian High Mountains

2017 ◽  
Vol 64 (243) ◽  
pp. 12-26 ◽  
Author(s):  
ROBERTO GARZONIO ◽  
BIAGIO DI MAURO ◽  
DANIELE STRIGARO ◽  
MICOL ROSSINI ◽  
ROBERTO COLOMBO ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Ice Core ◽  
Ice Cores ◽  
Weight Of Evidence ◽  
European Alps ◽  
High Mountains ◽  
Mountain Glacier ◽  
Past Climate ◽  
Core Drilling ◽  
Mountain Glaciers

ABSTRACTIce cores from mid-latitude mountain glaciers provide detailed information on past climate conditions and regional environmental changes, which is essential for placing current climate change into a longer term perspective. In this context, it is important to define guidelines and create dedicated maps to identify suitable areas for future ice-core drillings. In this study, the suitability for ice-core drilling (SICD) of a mountain glacier is defined as the possibility of extracting an ice core with preserved stratigraphy suitable for reconstructing past climate. Morphometric and climatic variables related to SICD are selected through literature review and characterization of previously drilled sites. A quantitative Weight of Evidence method is proposed to combine selected variables (i.e. slope, local relief, temperature and direct solar radiation) to map the potential drilling sites in mid-latitude mountain glaciers. The method was first developed in the European Alps and then applied to the Asian High Mountains. Model performances and limitations are discussed and first indications of new potential drilling sites in the Asian High Mountains are provided. Results presented here can facilitate the selection of future drilling sites especially on unexplored Asian mountain glaciers towards the understanding of climate and environmental changes.

Constraining ice core chronologies with 39Ar and 81Kr

2020 ◽  
Author(s):  
Florian Ritterbusch ◽  
Yan-Qing Chu ◽  
Ilaria Crotti ◽  
Xi-Ze Dong ◽  
Ji-Qiang Gu ◽  
...  
Keyword(s):  
Half Life ◽  
Earth Science ◽  
Noble Gas ◽  
Ice Core ◽  
Ice Cores ◽  
High Mountain ◽  
National Academy Of Sciences ◽  
Geophysical Research ◽  
Bottom Part ◽  
Mountain Glaciers

<p>Paleoclimate reconstructions from ice core records can be hampered due to the lack of a reliable chronology, especially when the stratigraphy is disturbed and conventional dating methods are not readily applied. The noble gas radioisotopes <sup>81</sup>Kr and <sup>39</sup>Ar can in these cases provide robust constraints as they yield absolute, radiometric ages. <sup>81</sup>Kr (half-life 229 ka) covers the time span from 50-1300 ka, which is particularly relevant for polar ice cores, whereas <sup>39</sup>Ar (half-life 269 a) with a dating range of 50-1400 a is suitable for high mountain glaciers. For a long time the use of <sup>81</sup>Kr and <sup>39</sup>Ar for dating of ice samples was hampered by the lack of a detection technique that can meet its extremely small abundance at a reasonable sample size. Here, we report on <sup>81</sup>Kr and <sup>39</sup>Ar dating of Antarctic and Tibetan ice cores with the detection method Atom Trap Trace Analysis (ATTA), using 5-10 kg of ice for <sup>81</sup>Kr and 2-5 kg for <sup>39</sup>Ar. Among others, we measured <sup>81</sup>Kr in the lower section of Taldice ice core, which is difficult to date by conventional methods, and in the meteoric bottom of the Vostok ice core in comparison with an age scale derived from hydrate growth. Moreover, we have obtained an <sup>39</sup>Ar profile for an ice core from central Tibet in combination with a timescale constructed by layer counting. The presented studies demonstrate how the obtained <sup>81</sup>Kr and <sup>39</sup>Ar ages can complement other methods in developing an ice core chronology, especially for the bottom part.</p><p>[1] Z.-T. Lu, Tracer applications of noble gas radionuclides in the geosciences, Earth-Science Reviews 138, 196-214, (2014)</p><p>[2] C. Buizert, Radiometric <sup>81</sup>Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica, Proceedings of the National Academy of Sciences, <strong>111</strong>, 6876, (2014)</p><p>[3] L. Tian, <sup>81</sup>Kr Dating at the Guliya Ice Cap, Tibetan Plateau, Geophysical Research Letters, (2019)</p><p>[4] http://atta.ustc.edu.cn</p>

Ice Memory

2021 ◽  
Author(s):  
Patrick Ginot ◽  
Jérôme Chappellaz ◽  
Carlo Barbante ◽  
Margit Schwikowski ◽  
Anne-Catherine Ohlmann
Keyword(s):  
Ice Cores ◽  
Global Scale ◽  
Governance System ◽  
Mountain Glaciers ◽  
Data Archives ◽  
The Future ◽  
Scientific Potential ◽  
Set Up ◽  
Maximum Parameters ◽  
Aerosol Emissions

<p>With global change and its amplified impact at high altitudes or in certain regions of the world, mountain glaciers are particularly sensitive to warming. These same glaciers, which have been studied for several decades, have made it possible to reconstruct, through the study of ice cores, unique information on the evolution of the climate or the environment on a regional and global scale since they are located closer to the main regions and sources of aerosol emissions. Unfortunately, these archives are in the process of being altered and are disappearing. It is in this context that the international project ICE MEMORY was initiated in 2015. ICE MEMORY is built on four pillars : 1) Identify, select glacier and extract several complete ice cores, at least two, from sites that have already demonstrated their high scientific potential before they are altered, 2) Analyse one of the cores in order to extract the maximum parameters of information using all currently available technologies and make this data available to the scientific community of today and tomorrow, 3) Store the remaining cores in a naturally adapted site such as the French-Italien Concordia station in Antarctica so that they can be preserved and donated to future generations of scientists, and 4) to set up a sustainable governance system based on an accredited international organization in charge of managing these ice and data archives in the future.</p><p>This presentation will highlight all the operations, analyses and organization already achieved as well as the future vision and development of ICE MEMORY.</p>

Ice Cores from Tropical Mountain Glaciers as Archives of Climate Change

2005 ◽  
pp. 31-38 ◽  
Author(s):  
Lonnie G. Thompson ◽  
Mary E. Davis ◽  
Ping-Nan Lin ◽  
Ellen Mosley-Thompson ◽  
Henry H. Brecher
Keyword(s):  
Climate Change ◽  
Ice Cores ◽  
Mountain Glaciers ◽  
Tropical Mountain

scholarly journals The first luminescence dating of Tibetan glacier basal sediment

2017 ◽  
Author(s):  
Zhu Zhang ◽  
Shugui Hou ◽  
Shuangwen Yi
Keyword(s):  
Tibetan Plateau ◽  
Seasonal Variations ◽  
Ice Cores ◽  
Older Age ◽  
Luminescence Dating ◽  
High Mountain ◽  
Mountain Glaciers ◽  
Ice Cap ◽  
Basal Ice ◽  
Upper Limit

Abstract. Dating of ice cores drilled in the high mountain glaciers is difficult because seasonal variations cannot be traced at depth due to rapid thinning of the ice layers. Here we provide the first luminescence dating of the basal sediment of the Chongce ice cap in the northwest Tibetan Plateau. Assuming the sediment is of similar (or older) age as the surrounding ice, the dating result of 42 ± 4 ka provides an upper limit for the age of the ice cap. This result is more than one magnitude younger than the previously suggested age of the basal ice of the nearby Guliya ice cap (~ 40 km in distance).

scholarly journals The first luminescence dating of Tibetan glacier basal sediment

2018 ◽  
Vol 12 (1) ◽  
pp. 163-168 ◽  
Author(s):  
Zhu Zhang ◽  
Shugui Hou ◽  
Shuangwen Yi
Keyword(s):  
Ice Cores ◽  
Luminescence Dating ◽  
High Mountain ◽  
Mountain Glaciers ◽  
Ice Cap ◽  
The North ◽  
Basal Ice ◽  
Order Of Magnitude ◽  
Western Tibetan Plateau ◽  
Drilling Site

Abstract. Dating ice cores drilled in the high mountain glaciers is difficult because seasonal variations cannot be traced at depth due to rapid thinning of the ice layers. Here we provide the first luminescence dating of the basal sediment of the Chongce ice cap in the north-western Tibetan Plateau. Assuming the sediment is of similar (or older) age as the surrounding ice, the luminescence dating of 42 ± 4 ka provides an upper constraint for the age of the bottom ice at the drilling site. This result is more than 1 order of magnitude younger than the previously suggested age of the basal ice of the nearby Guliya ice cap (∼ 40 km in distance).

scholarly journals Global glacier dynamics during 100 ka Pleistocene glacial cycles

2018 ◽  
Vol 90 (1) ◽  
pp. 222-243 ◽  
Author(s):  
Philip D. Hughes ◽  
Philip L. Gibbard
Keyword(s):  
Solar Radiation ◽  
Global Climate ◽  
Ice Cores ◽  
External Control ◽  
Glacial Cycles ◽  
Mountain Glaciers ◽  
Ice Volume ◽  
Double Peaks ◽  
Dust Flux ◽  
Solar Radiation Flux

AbstractIce volume during the last ten 100 ka glacial cycles was driven by solar radiation flux in the Northern Hemisphere. Early minima in solar radiation combined with critical levels of atmospheric CO2drove initial glacier expansion. Glacial cycles between Marine Isotope Stage (MIS) 24 and MIS 13, whilst at 100 ka periodicity, were irregular in amplitude, and the shift to the largest amplitude 100 ka glacial cycles occurred after MIS 16. Mountain glaciers in the mid-latitudes and Asia reached their maximum extents early in glacial cycles, then retreated as global climate became increasingly arid. In contrast, larger ice masses close to maritime moisture sources continued to build up and dominated global glacial maxima reflected in marine isotope and sea-level records. The effect of this pattern of glaciation on the state of the global atmosphere is evident in dust records from Antarctic ice cores, where pronounced double peaks in dust flux occur in all of the last eight glacial cycles. Glacier growth is strongly modulated by variations in solar radiation, especially in glacial inceptions. This external control accounts for ~50–60% of ice volume change through glacial cycles. Internal global glacier–climate dynamics account for the rest of the change, which is controlled by the geographic distributions of glaciers.

Seasonal variations in the properties and structural composition of sea ice and snow cover in the Bellingshausen and Amundsen Seas, Antarctica

1997 ◽  
Vol 43 (143) ◽  
pp. 138-151 ◽  
Author(s):  
M. O. Jeffries ◽  
K. Morris ◽  
W.F. Weeks ◽  
A. P. Worby
Keyword(s):  
Sea Ice ◽  
Isotopic Composition ◽  
Snow Cover ◽  
Sea Water ◽  
Ice Cores ◽  
Ice Cover ◽  
Snow Accumulation ◽  
Ice Formation ◽  
Frazil Ice ◽  
Core Sets

AbstractSixty-three ice cores were collected in the Bellingshausen and Amundsen Seas in August and September 1993 during a cruise of the R.V. Nathaniel B. Palmer. The structure and stable-isotopic composition (18O/16O) of the cores were investigated in order to understand the growth conditions and to identify the key growth processes, particularly the contribution of snow to sea-ice formation. The structure and isotopic composition of a set of 12 cores that was collected for the same purpose in the Bellingshausen Sea in March 1992 are reassessed. Frazil ice and congelation ice contribute 44% and 26%, respectively, to the composition of both the winter and summer ice-core sets, evidence that the relatively calm conditions that favour congelation-ice formation are neither as common nor as prolonged as the more turbulent conditions that favour frazil-ice growth and pancake-ice formation. Both frazil- and congelation-ice layers have an av erage thickness of 0.12 m in winter, evidence that congelation ice and pancake ice thicken primarily by dynamic processes. The thermodynamic development of the ice cover relies heavily on the formation of snow ice at the surface of floes after sea water has flooded the snow cover. Snow-ice layers have a mean thickness of 0.20 and 0.28 m in the winter and summer cores, respectively, and the contribution of snow ice to the winter (24%) and summer (16%) core sets exceeds most quantities that have been reported previously in other Antarctic pack-ice zones. The thickness and quantity of snow ice may be due to a combination of high snow-accumulation rates and snow loads, environmental conditions that favour a warm ice cover in which brine convection between the bottom and top of the ice introduces sea water to the snow/ice interface, and bottom melting losses being compensated by snow-ice formation. Layers of superimposed ice at the top of each of the summer cores make up 4.6% of the ice that was examined and they increase by a factor of 3 the quantity of snow entrained in the ice. The accumulation of superimposed ice is evidence that melting in the snow cover on Antarctic sea-ice floes ran reach an advanced stage and contribute a significant amount of snow to the total ice mass.

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