Glacial Stage Ice-Core Records from the Subtropical Dunde Ice Cap, China

The first ice-core record of both the Holocene and Wisconsin/Würm Late Glacial Stage (LGS) from the subtropics has been extracted from three ice cores to bedrock from the Dunde ice cap on the north-central Qinghai-Tibetan Plateau. Ice thicknesses at the ice-cap summit average 138 m, the bedrock surface is relatively flat, surface and basal temperatures are −7.3 and −4.7°C, respectively and the ice cap exhibits radial flow away from the summit dome. These records reveal a major change in the climate of the plateau ∼10 000 years ago and suggest that LGS conditions were colder, wetter and dustier than Holocene conditions. This is inferred from the more negative δ18O ratios, increased dust content, decreased soluble aerosol concentrations, and reduced ice-crystal sizes, which characterize the LGS part of the cores. Total β radioactivity from shallow ice cores indicates that over the last 24 years the average accumulation rate has been ∼400 mm a−1 at the summit. The ice cores have been dated using a combination of annual layers in the insoluble dust and δ18O in the upper sections of core, visible dust layers which are annual, and ice-flow modeling. The oxygen-isotope record which serves as a temperature proxy indicates that the last 60 years have been the warmest in the entire record.

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Age ranges of the Tibetan ice cores with emphasis on the Chongce ice cores, western Kunlun Mountains

The Cryosphere ◽

10.5194/tc-12-2341-2018 ◽

2018 ◽

Vol 12 (7) ◽

pp. 2341-2348 ◽

Cited By ~ 9

Author(s):

Shugui Hou ◽

Theo M. Jenk ◽

Wangbin Zhang ◽

Chaomin Wang ◽

Shuangye Wu ◽

...

Keyword(s):

Ice Core ◽

Ice Cores ◽

High Elevation ◽

The Other ◽

Ice Cap ◽

The North ◽

Kunlun Mountains ◽

Guliya Ice Core ◽

Western Kunlun ◽

Drilling Site

Abstract. An accurate chronology is the essential first step for a sound understanding of ice core records. However, dating ice cores drilled from the high-elevation glaciers is challenging and often problematic, leading to great uncertainties. The Guliya ice core, drilled to the bedrock (308.6 m in length) along the western Kunlun Mountains on the north-western Tibetan Plateau (TP) and widely used as a benchmark for palaeoclimate research, is believed to reach >500 ka (thousand years) at its bottom. Meanwhile other Tibetan ice cores (i.e. Dasuopu and East Rongbuk in the Himalayas, Puruogangri in the central TP and Dunde in the north-eastern TP) are mostly of Holocene origin. In this study, we drilled four ice cores into bedrock (216.6, 208.6, 135.8 and 133.8 m in length, respectively) from the Chongce ice cap ∼30 km to the Guliya ice core drilling site. We took measurements of 14C, 210Pb, tritium and β activity for the ice cores, and used these values in a two-parameter flow model to establish the ice core depth–age relationship. We suggested that the Chongce ice cores might be of Holocene origin, consistent with the other Tibetan ice cores except Guliya. The remarkable discrepancy between the Guliya and all the other Tibetan ice core chronology implies that more effort is necessary to explore multiple dating techniques to confirm the age ranges of the TP glaciers, including those from Chongce and Guliya.

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A first chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core

Climate of the Past ◽

10.5194/cp-9-2713-2013 ◽

2013 ◽

Vol 9 (6) ◽

pp. 2713-2730 ◽

Cited By ~ 85

Author(s):

S. O. Rasmussen ◽

P. M. Abbott ◽

T. Blunier ◽

A. J. Bourne ◽

E. Brook ◽

...

Keyword(s):

Accumulation Rate ◽

Ice Core ◽

Conductivity Measurement ◽

Ice Cores ◽

Heat Diffusion ◽

Ice Age ◽

Age Difference ◽

Volcanic Origin ◽

The North ◽

North Greenland

Abstract. A stratigraphy-based chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core has been derived by transferring the annual layer counted Greenland Ice Core Chronology 2005 (GICC05) and its model extension (GICC05modelext) from the NGRIP core to the NEEM core using 787 match points of mainly volcanic origin identified in the electrical conductivity measurement (ECM) and dielectrical profiling (DEP) records. Tephra horizons found in both the NEEM and NGRIP ice cores are used to test the matching based on ECM and DEP and provide five additional horizons used for the timescale transfer. A thinning function reflecting the accumulated strain along the core has been determined using a Dansgaard–Johnsen flow model and an isotope-dependent accumulation rate parameterization. Flow parameters are determined from Monte Carlo analysis constrained by the observed depth-age horizons. In order to construct a chronology for the gas phase, the ice age–gas age difference (Δage) has been reconstructed using a coupled firn densification-heat diffusion model. Temperature and accumulation inputs to the Δage model, initially derived from the water isotope proxies, have been adjusted to optimize the fit to timing constraints from δ15N of nitrogen and high-resolution methane data during the abrupt onset of Greenland interstadials. The ice and gas chronologies and the corresponding thinning function represent the first chronology for the NEEM core, named GICC05modelext-NEEM-1. Based on both the flow and firn modelling results, the accumulation history for the NEEM site has been reconstructed. Together, the timescale and accumulation reconstruction provide the necessary basis for further analysis of the records from NEEM.

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Secular Trends Of Accumulation Rate On Ice Cores From Dunde Ice Cap, China Over The Last 1000 Years

Annals of Glaciology ◽

10.3189/s0260305500009423 ◽

1990 ◽

Vol 14 ◽

pp. 363-363

Author(s):

Wu Xiaoling ◽

Li Zhongqin ◽

Xie Zichu

Keyword(s):

Accumulation Rate ◽

Ice Core ◽

Ice Cores ◽

Surface Strain ◽

Entire Length ◽

Ice Age ◽

Cooperative Research ◽

Ice Cap ◽

Annual Layer ◽

Lanzhou Institute

Cooperative research programs were conducted on the Dunde Ice Cap (38°06′N, 96°26′E), China, in 1984, 1986, 1987, by the Lanzhou Institute of Glaciology and Geocryology (LIGG), China and the Byrd Polar Research Center (BPRC), U.S.A. This paper gives the preliminary results of the analysis on accumulation rate of the ice cap over the last 1000 years. Three ice cores were recovered to bedrock from the ice-cap summit (5324 m a.s.l.). Core D-1 (139.8 m long) was divided in the field along the entire length and was shared equally between LIGG and BPRC. Core D-2 (136.6 m long) was returned frozen complete to the LIGG for ice-core measurements. In Core D-3 (138.4 m long) the upper sectors were melted and bottled in the field and the lower sectors were returned frozen to the BPRC, U.S.A. Core D-1 was analyzed in China along the entire length for oxygen isotope, liquid conductivity and pH. A year-by-year dating of the ice cores has been made with Dansgaard-Johnsen’s flow pattern by using the data of surface strain-rate (August 1986 to August 1987) and tritium measurements. The resulting time-scales of the ice cores in Dunde Ice Cap yield an age of 4600 yr B.P. The annual layer thicknesses of core D-1 were measured mainly by δ18O analysis and liquid conductivity. The lower δ18O is generally associated with higher electrical conductivity. Annual layer thickness was converted to accumulation rates and compared with meteorological records from Delingxa Meteorological Station. The mean accumulation rate is 518 mm in ice-equivalent. Particular attention is given to the possible impact of the Little Ice Age. Based on spectral analysis of time series for the accumulation variation with depth, short-term (30, 33 year at 0.01 level) and intermediate-term variation (120 year) were discussed. The ice-core research program has been supported by the Chinese National Foundation of Natural Science under Grant DO125-4860011.

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Secular Trends Of Accumulation Rate On Ice Cores From Dunde Ice Cap, China Over The Last 1000 Years

Annals of Glaciology ◽

10.1017/s0260305500009423 ◽

1990 ◽

Vol 14 ◽

pp. 363

Author(s):

Wu Xiaoling ◽

Li Zhongqin ◽

Xie Zichu

Keyword(s):

Accumulation Rate ◽

Ice Core ◽

Ice Cores ◽

Surface Strain ◽

Entire Length ◽

Ice Age ◽

Cooperative Research ◽

Ice Cap ◽

Annual Layer ◽

Lanzhou Institute

Cooperative research programs were conducted on the Dunde Ice Cap (38°06′N, 96°26′E), China, in 1984, 1986, 1987, by the Lanzhou Institute of Glaciology and Geocryology (LIGG), China and the Byrd Polar Research Center (BPRC), U.S.A. This paper gives the preliminary results of the analysis on accumulation rate of the ice cap over the last 1000 years. Three ice cores were recovered to bedrock from the ice-cap summit (5324 m a.s.l.). Core D-1 (139.8 m long) was divided in the field along the entire length and was shared equally between LIGG and BPRC. Core D-2 (136.6 m long) was returned frozen complete to the LIGG for ice-core measurements. In Core D-3 (138.4 m long) the upper sectors were melted and bottled in the field and the lower sectors were returned frozen to the BPRC, U.S.A. Core D-1 was analyzed in China along the entire length for oxygen isotope, liquid conductivity and pH. A year-by-year dating of the ice cores has been made with Dansgaard-Johnsen’s flow pattern by using the data of surface strain-rate (August 1986 to August 1987) and tritium measurements. The resulting time-scales of the ice cores in Dunde Ice Cap yield an age of 4600 yr B.P. The annual layer thicknesses of core D-1 were measured mainly by δ18O analysis and liquid conductivity. The lower δ18O is generally associated with higher electrical conductivity. Annual layer thickness was converted to accumulation rates and compared with meteorological records from Delingxa Meteorological Station. The mean accumulation rate is 518 mm in ice-equivalent. Particular attention is given to the possible impact of the Little Ice Age. Based on spectral analysis of time series for the accumulation variation with depth, short-term (30, 33 year at 0.01 level) and intermediate-term variation (120 year) were discussed. The ice-core research program has been supported by the Chinese National Foundation of Natural Science under Grant DO125-4860011.

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Late Glacial Input of Eolian Continental Dust in the Dome C Ice Core: Additional Evidence from Individual Microparticle Analysis

Annals of Glaciology ◽

10.1017/s0260305500002470 ◽

1982 ◽

Vol 3 ◽

pp. 27-31 ◽

Cited By ~ 35

Author(s):

M. Briat ◽

A. Royer ◽

J. R. Petit ◽

C. Lorius

Keyword(s):

Ice Core ◽

Trace Element Analysis ◽

Ice Cores ◽

Late Glacial ◽

Ice Age ◽

Quartz Content ◽

Element Analysis ◽

Volcanic Origin ◽

Glacial Stage ◽

The Antarctic

399 individual microparticles in nine samples from the Dome C ice core were studied under scanning electron microscope and analysed by an energy dispersive X-ray system. The studied particles were either continental quartz or various silico-aluminates of continental or volcanic origin. Observations lead to the conclusion that the increase in micro particle concentration by a factor of 10 to 20 during the last glacial stage is explained by a large input of continental dust, as already indicated by trace element analysis (Petit and others 1981) and previously suggested by chemical analysis of other polar ice cores (Cragin and others 1977).This increase is considered to be a consequence of the ice-age climate and earth surface conditions which were characterized by the increase of arid regions and more vigorous atmospheric circulation. Both these conclusions are further supported by the existence of a higher quartz content in the Antarctic ice core as was already found in tropical deep-sea core studies.

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Late Glacial Input of Eolian Continental Dust in the Dome C Ice Core: Additional Evidence from Individual Microparticle Analysis

Annals of Glaciology ◽

10.3189/s0260305500002470 ◽

1982 ◽

Vol 3 ◽

pp. 27-31 ◽

Cited By ~ 4

Author(s):

M. Briat ◽

A. Royer ◽

J. R. Petit ◽

C. Lorius

Keyword(s):

Ice Core ◽

Trace Element Analysis ◽

Ice Cores ◽

Late Glacial ◽

Ice Age ◽

Quartz Content ◽

Element Analysis ◽

Volcanic Origin ◽

Glacial Stage ◽

The Antarctic

399 individual microparticles in nine samples from the Dome C ice core were studied under scanning electron microscope and analysed by an energy dispersive X-ray system. The studied particles were either continental quartz or various silico-aluminates of continental or volcanic origin. Observations lead to the conclusion that the increase in micro particle concentration by a factor of 10 to 20 during the last glacial stage is explained by a large input of continental dust, as already indicated by trace element analysis (Petit and others 1981) and previously suggested by chemical analysis of other polar ice cores (Cragin and others 1977).This increase is considered to be a consequence of the ice-age climate and earth surface conditions which were characterized by the increase of arid regions and more vigorous atmospheric circulation. Both these conclusions are further supported by the existence of a higher quartz content in the Antarctic ice core as was already found in tropical deep-sea core studies.

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A new method of resolving annual precipitation for the past millennia from Tibetan ice cores

10.5194/tc-2021-115 ◽

2021 ◽

Author(s):

Wangbin Zhang ◽

Shugui Hou ◽

Shuang-Ye Wu ◽

Hongxi Pang ◽

Sharon B. Sneed ◽

...

Keyword(s):

High Resolution ◽

Inductively Coupled Plasma ◽

Flow Model ◽

Accumulation Rate ◽

Ice Core ◽

Ice Cores ◽

New Method ◽

Inductively Coupled ◽

Ice Cap ◽

Thinning Parameter

Abstract. Net accumulation records derived from ice cores provide the most direct measurement of past precipitation. However, quantitative reconstruction of accumulation for past millennia remains challenging due to the difficulty in identifying annual layers in the deeper sections of ice cores. In this study, we propose a new method to quantify annual accumulation from ice cores for past millennia, using as an example an ice core drilled at the Chongce ice cap in the northwestern Tibetan Plateau (TP). First, we used the Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) technology to develop an ultra-high-resolution trace element records in three sections of the ice core and identified annual layers in each section based on seasonality of these elements. Second, based on nine 14C ages determined for this ice core, we developed a two-parameter flow model to established the thinning parameter of this ice core. Finally, we converted the thickness of annual layers in the three sample sections to past accumulation rates based on the thinning parameter derived from the ice-flow model. Our results show that the mean annual accumulation rate for the three sample sections are 102 mm/year (2511–2541 a B.P.), 76 mm/year (1682–1697 a B.P.) and 84 mm/year (781–789 a B.P.). For comparison, the Holocene mean precipitation is 103 mm/year. This method has the potential to reconstruct continuous high-resolution precipitation records covering millennia or even longer time periods.

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Influence of regional precipitation patterns on stable isotopes in ice cores from the central Himalayas

The Cryosphere Discussions ◽

10.5194/tcd-7-1871-2013 ◽

2013 ◽

Vol 7 (3) ◽

pp. 1871-1905 ◽

Cited By ~ 1

Author(s):

H. Pang ◽

S. Hou ◽

S. Kaspari ◽

P. A. Mayewski

Keyword(s):

Ice Core ◽

Precipitation Amount ◽

Ice Cores ◽

Central Himalayas ◽

Precipitation Patterns ◽

The North ◽

Stable Isotopic ◽

Dasuopu Ice Core ◽

Isotopic Records ◽

Temperature Proxy

Abstract. Several ice cores have been recovered from the Dasuopu Glacier and the East Rongbuk (ER) Glacier in the central Himalayas since the 1990s. Although the distance between the ER and the Dasuopu ice core drilling sites is only ∼125 km, the stable isotopic record (δ18O or δD) of the ER core is interpreted as a precipitation proxy while the Dasuopu core as a temperature proxy. Thus, the climatological significance of the stable isotopic records of these Himalayan ice cores remains a subject of debate. Based on analysis of regional precipitation patterns over the region, we find that the different interpretations of the Dasuopu and Everest isotopic records may not be contradictive. The north–south and west–east seesaws of the Indian Summer Monsoon (ISM) precipitation are primarily responsible for precipitation falling at the ER site, which results in a negative correlation between the ER δ18O or δD record and precipitation amount along the southern slope of the central Himalayas, corresponding to the "amount effect". In addition to the ISM precipitation, non-summer monsoonal precipitation associated with winter westerlies also significantly contributes to precipitation falling at the Dasuopu site, which may cause a positive correlation between the Dasuopu stable isotopic record and temperature, in response to the "temperature effect". Our results have important implications for interpreting the stable isotopic ice core records recovered from different climatological regimes of the Himalayas.

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Eclipse Ice Core Accumulation and Stable Isotope Variability as an Indicator of North Pacific Climate

Journal of Climate ◽

10.1175/jcli-d-11-00389.1 ◽

2012 ◽

Vol 25 (18) ◽

pp. 6426-6440 ◽

Cited By ~ 6

Author(s):

Eric P. Kelsey ◽

Cameron P. Wake ◽

Kaplan Yalcin ◽

Karl Kreutz

Keyword(s):

Stable Isotope ◽

North Pacific ◽

Geopotential Height ◽

Accumulation Rate ◽

Ice Core ◽

Ice Cores ◽

Cold Season ◽

High Accumulation ◽

The North ◽

The Individual

Abstract The high accumulation rate and negligible amount of melt at Eclipse Icefield (3017 m) in the Saint Elias Range of Yukon, Canada, allows for the preservation of a high-resolution isotopic and glaciochemical records valuable for reconstruction of climatic variables. Each of the three Eclipse ice cores have a well-constrained depth–age scale with dozens of reference horizons over the twentieth century that permits an exceptional level of confidence in the results of the current calibration exercise. Stacked time series of accumulation and stable isotopes were divided into cold and warm seasons and seasons of extreme high and extreme low accumulation and stable isotope values (eight groups). For each group, season-averaged composites of 500-hPa geopotential height grids, and the individual seasons that constitute them, were analyzed to elucidate common anomalous flow patterns. This analysis shows that the most fractionated isotopes and lowest accumulation cold seasons reflect a more zonal height pattern in the North Pacific associated with negative Pacific–North American (PNA) and Pacific decadal oscillation (PDO) indices. Conversely, the least fractionated isotopes and highest accumulation cold seasons are associated with a positive PNA pattern. Although only a maximum of approximately 20% of the total number of accumulation and stable isotope seasons exhibit a relatively consistent relationship with 500-hPa geopotential height patterns, these results support the hypothesis that the most extreme accumulation and extreme isotope cold-season values in the Saint Elias Mountains are related to consistent atmospheric circulation and oceanic sea surface temperature patterns.

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