scholarly journals Age of the Tibetan ice cores

2018 ◽  
Author(s):  
Shugui Hou ◽  
Wangbin Zhang ◽  
Chaomin Wang ◽  
Shuangye Wu ◽  
Yetang Wang ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
High Elevation ◽  
Significant Discrepancy ◽  
Ice Cap ◽  
Guliya Ice Core ◽  
Ice Core Record ◽  
Core Depth ◽  
Drilling Site ◽  
Two Parameter

Abstract. An accurate chronology is the essential first step for a sound understanding of ice core records, however, dating of ice cores drilled from the high elevation glaciers is challenging and often problematic, leading to great uncertainties. The Guliya ice core, drilled to bedrock (308.6 m in length) from the northwestern Tibetan Plateau (TP) and widely used as a benchmark for paleoclimate 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 northeastern TP) are mostly of the Holocene origin. In this study, we drilled ice cores to bedrock from the Chongce ice cap ~ 30 km from the Guliya ice core drilling site. We performed 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. The modeled ages of two Chongce ice cores at the ice-bedrock contact are 8.3 ± 6.2/3.6 ka B.P. and 9.0 ± 7.9/3.6 ka B.P. respectively. The significant discrepancy between the Guliya and all other Tibetan ice core chronologies calls for a revisit of this legend ice core record.

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

2018 ◽  
Vol 12 (7) ◽  
pp. 2341-2348 ◽  
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.

scholarly journals Apparent discrepancy of Tibetan ice core <i>δ</i><sup>18</sup>O records may be attributed to misinterpretation of chronology

2019 ◽  
Vol 13 (6) ◽  
pp. 1743-1752 ◽  
Author(s):  
Shugui Hou ◽  
Wangbin Zhang ◽  
Hongxi Pang ◽  
Shuang-Ye Wu ◽  
Theo M. Jenk ◽  
...  
Keyword(s):  
High Resolution ◽  
Ice Core ◽  
Ice Cores ◽  
Warming Trend ◽  
The Tibetan Plateau ◽  
Apparent Discrepancy ◽  
Ice Cap ◽  
Guliya Ice Core ◽  
Cooling Trend ◽  
Instrumental Period

Abstract. Ice cores from the Tibetan Plateau (TP) are widely used for reconstructing past climatic and environmental conditions that extend beyond the instrumental period. However, challenges in dating and interpreting ice core records often lead to inconsistent results. The Guliya ice core drilled from the northwestern TP suggested a cooling trend during the mid-Holocene based on its decreasing δ18O values, which is not observed in other Tibetan ice cores. Here we present a new high-resolution δ18O record of the Chongce ice cores drilled to bedrock ∼30 km away from the Guliya ice cap. Our record shows a warming trend during the mid-Holocene. Based on our results as well as previously published ice core data, we suggest that the apparent discrepancy between the Holocene δ18O records of the Guliya and the Chongce ice cores may be attributed to a possible misinterpretation of the Guliya ice core chronology.

scholarly journals A 1000 year climate ice-core record from the Guliya ice cap, China: its relationship to global climate variability

1995 ◽  
Vol 21 ◽  
pp. 175-181 ◽  
Author(s):  
L. G. Thompson ◽  
E. Mosley-Thompson ◽  
M.E. Davis ◽  
P.N. Lin ◽  
J. Dai ◽  
...  
Keyword(s):  
Global Climate ◽  
Monsoon Season ◽  
Eastern China ◽  
Ice Core ◽  
Ice Cores ◽  
Ice Age ◽  
Ice Cap ◽  
Western Kunlun ◽  
Ice Core Record ◽  
Western Side

In 1992, an American-Chinese expedition successfully recovered three ice cores (308.6, 93.2 and 34.5m) from the Guliya ice cap (summit 6710 m a.s.l) in the far western Kunlun on the Qinghai–Tibetan Plateau, China. Guliya resembles a “polar” icecap with 10 m, 200 m and basal temperatures of –15.6°, –5.9° and –2.1°C, respectively. The 308.6 m core to bedrock is the longest ice core retrieved from an elevation greater than 4000 m a.s.l. and provides the first ice-core history from the western side of the Qinghai Plateau. The Plateau experiences a pronounced annual precipitation cycle during which 70–80% of annual total precipitation falls in the summer monsoon season. This leads to a marked visible stratigraphy in the glaciers which allows accurate dating of the ice cores and reconstruction of the net mass accumulation. This paper presents (1) the results of the geophysical program to determine ice thickness, ice flow and surface topography, (2) an assessment of net accumulation from stake measurements, snow pits and shallow core samples, and (3) the analyses of the upper 100 m of the 308.6 m core which provide a 1000 year history, including the ‘“Little Ice Age”, which is compared with Chinese historical records. Extended periods of positive accumulation on Guliya are closely contemporaneous with dry periods in eastern China. A trans-Pacific teleconnection is suggested by the strong temporal coherence between extended wet and dry phases on Guliya and on the Quelccaya ice cap, Peru.

scholarly journals A potential high-elevation ice-core site at Hielo Patagόnico Sur

2006 ◽  
Vol 43 ◽  
pp. 8-13 ◽  
Author(s):  
Margit Schwikowski ◽  
Sabina Brütsch ◽  
Gino Casassa ◽  
Andrés Rivera
Keyword(s):  
Wind Erosion ◽  
Ice Core ◽  
Ice Cores ◽  
High Elevation ◽  
The Core ◽  
Clear Sign ◽  
Southern Patagonia ◽  
Core Site ◽  
Ice Core Record ◽  
Good Potential

AbstractThe Patagonia icefields constitute a unique location in the Southern Hemisphere for obtaining non-polar paleo-records from ice cores south of 45°S. Nevertheless, no ice-core record with meaningful paleoclimate information has yet been obtained from Patagonia. This deficiency is due to extremely harsh field conditions, and to the fact that the main plateaus of both Hielo Patagónico Norte (HPN; northern Patagonia icefield) and Hielo Patagónico Sur (HPS; southern Patagonia icefield) are strongly affected by meltwater percolation. In order to explore the suitability of high-elevation glacier sites at HPS as paleoclimate archives, three shallow firn cores were retrieved covering the altitude range 1543−2300 ma.s.l. The glaciochemical records from the two lower sites confirm the presence of superimposed ice, a clear sign of meltwater formation and percolation. In the core from 2300 m, the glaciochemical signature appears to be preserved, indicating that no significant melting occurred. Although there might be problems associated with wind erosion and extreme melt events, there is good potential for well-preserved paleo-records within glaciers in the Patagonia icefields located higher than 2300 m.

scholarly journals Apparent discrepancy of Tibetan ice core δ<sup>18</sup>O records may be attributed to misinterpretation of chronology

2019 ◽  
Author(s):  
Shugui Hou ◽  
Wangbin Zhang ◽  
Hongxi Pang ◽  
Shuangye Wu ◽  
Theo M. Jenk ◽  
...  
Keyword(s):  
High Resolution ◽  
Ice Core ◽  
Ice Cores ◽  
Warming Trend ◽  
The Tibetan Plateau ◽  
Apparent Discrepancy ◽  
Ice Cap ◽  
Guliya Ice Core ◽  
Cooling Trend ◽  
Instrumental Period

Abstract. Ice cores from the Tibetan Plateau (TP) are widely used for reconstructing past climatic and environmental conditions that extend beyond the instrumental period. However, challenges in dating and interpreting ice core records often lead to inconsistent results. The Guliya ice core drilled from the northwestern TP suggested a cooling trend during the mid-Holocene based on its decreasing δ18O values, which is not observed in other Tibetan ice cores. Here we present a new high-resolution δ18O record of the Chongce ice cores drilled to bedrock ~ 30 km away from the Guliya ice cap. Our record shows a warming trend during the mid-Holocene. Based on our results as well as previously published ice core data, we suggest that the apparent discrepancy between the Holocene δ18O records of the Guliya and the Chongce ice cores may be attributed to a possible misinterpretation of the Guliya ice core chronology.

scholarly journals A 1000 year climate ice-core record from the Guliya ice cap, China: its relationship to global climate variability

1995 ◽  
Vol 21 ◽  
pp. 175-181 ◽  
Author(s):  
L. G. Thompson ◽  
E. Mosley-Thompson ◽  
M.E. Davis ◽  
P.N. Lin ◽  
J. Dai ◽  
...  
Keyword(s):  
Global Climate ◽  
Monsoon Season ◽  
Eastern China ◽  
Ice Core ◽  
Ice Cores ◽  
Ice Age ◽  
Ice Cap ◽  
Western Kunlun ◽  
Ice Core Record ◽  
Western Side

In 1992, an American-Chinese expedition successfully recovered three ice cores (308.6, 93.2 and 34.5m) from the Guliya ice cap (summit 6710 m a.s.l) in the far western Kunlun on the Qinghai–Tibetan Plateau, China. Guliya resembles a “polar” icecap with 10 m, 200 m and basal temperatures of –15.6°, –5.9° and –2.1°C, respectively. The 308.6 m core to bedrock is the longest ice core retrieved from an elevation greater than 4000 m a.s.l. and provides the first ice-core history from the western side of the Qinghai Plateau. The Plateau experiences a pronounced annual precipitation cycle during which 70–80% of annual total precipitation falls in the summer monsoon season. This leads to a marked visible stratigraphy in the glaciers which allows accurate dating of the ice cores and reconstruction of the net mass accumulation.This paper presents (1) the results of the geophysical program to determine ice thickness, ice flow and surface topography, (2) an assessment of net accumulation from stake measurements, snow pits and shallow core samples, and (3) the analyses of the upper 100 m of the 308.6 m core which provide a 1000 year history, including the ‘“Little Ice Age”, which is compared with Chinese historical records. Extended periods of positive accumulation on Guliya are closely contemporaneous with dry periods in eastern China. A trans-Pacific teleconnection is suggested by the strong temporal coherence between extended wet and dry phases on Guliya and on the Quelccaya ice cap, Peru.

scholarly journals Glaciological Investigations of the Tropical Quelccaya Ice Cap, Peru

1980 ◽  
Vol 25 (91) ◽  
pp. 69-84 ◽  
Author(s):  
Lonnie G. Thompson
Keyword(s):  
Rainy Season ◽  
Ice Core ◽  
Ice Cores ◽  
Dry Season ◽  
Radioactive Material ◽  
Polar Regions ◽  
Near Surface ◽  
Ice Cap ◽  
Activity Measurements ◽  
Quelccaya Ice Cap

AbstractGlaciological results of the continuing investigations of the Quelccaya ice cap located at lat. 13° 56’ S., long. 70° 50’ W., in the Cordillera Oriental of southern Peru are presented. Ice cores to a depth of 15 m have been retrieved from the summit dome (5650 m), middle dome (5543 m), and south dome (5480 m) and sampled in detail for microparticle, oxygen-isotope, and total-β-activity measurements. Results of these core analyses indicate that although the summit of this ice cap is only 300 m above the annual snow line and the firn is temperate, an interpretable stratigraphic record is preserved. The marked seasonal ice stratigraphy is produced by the marked seasonal variation in regional precipitation. High concentrations of microparticles and β- radioactive material occur during the dry season (May-August). Microparticles deposited during the rainy season are larger than those deposited during the dry season. On the Quelccaya ice cap the most negative δ18O values occur during the warmer rainy season (the opposite occurs in polar regions). The near-surface mean δ value of – 21‰ is remarkably low for this tropical site where the measured mean annual air temperature is – 3°C The seasonality of the microparticles, total β activity, and isotope ratios offers the prospect of a climatic ice-core record from this tropical ice cap.

scholarly journals Brief communication: New evidence further constraining Tibetan ice core chronologies to the Holocene

2021 ◽  
Vol 15 (4) ◽  
pp. 2109-2114
Author(s):  
Shugui Hou ◽  
Wangbin Zhang ◽  
Ling Fang ◽  
Theo M. Jenk ◽  
Shuangye Wu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Ice Core ◽  
Ice Cores ◽  
Qilian Mountains ◽  
Time Range ◽  
The Holocene ◽  
Guliya Ice Core ◽  
Considerable Controversy ◽  
New Evidence

Abstract. There is considerable controversy regarding the age ranges of Tibetan ice cores. The Guliya ice core was reported to reach as far back as ∼760 ka (kiloannum, i.e. 1000 years), whereas chronologies of all other Tibetan cores cover at most the Holocene. Here we present ages for two new ice cores reaching bedrock, from the Zangser Kangri (ZK) glacier in the northwestern Tibetan Plateau and the Shulenanshan (SLNS) glacier in the western Qilian Mountains. We estimated bottom ages of 8.90±0.570.56 ka and 7.46±1.461.79 ka for the ZK and SLNS ice core respectively, further constraining the time range accessible by Tibetan ice cores to the Holocene.

scholarly journals Mass-balance variability as a base for interpreting ice-core data

1995 ◽  
Vol 21 ◽  
pp. 201-205
Author(s):  
V. N. Mikhalenko
Keyword(s):  
Mass Balance ◽  
Extreme Values ◽  
Ice Core ◽  
Ice Cores ◽  
Tien Shan ◽  
Glacier Mass Balance ◽  
Similarity Type ◽  
Glacier System ◽  
Point Analysis ◽  
Drilling Site

The spatial extrapolation of data from ice cores depends on the complexity of the glacier system where the drilling site is located. The correlation between net mass balance, bn, of a specific point and of the whole glacier is different for each point. Analysis of net mass balance of Tuyuksu glacier in the Tien Shan, central Asia, confirms that the distribution of mass balance with height is more-or-less constant from year to year except in years with extreme values bn. Two types of “similarity” are described, additive and multiplicative. The “similarity” changes gradually from additive at the peripheral parts of the Tien Shan to multiplicative in the most continental central and eastern parts. Glacier mass-balance fluctuations of the frontal ridges are connected to the oscillations of accumulation and consequently to precipitation. Where the climate is more continental the mass-balance variability depends much more on the melting conditions than on accumulation. For the spatial interpretation of ice-core drilling results, a special analysis of “similarity type” is necessary. It allows the fixing of the spatial borders of the glacier system for which the dhilling site is representative.

scholarly journals Climatic Records from the Dunde Ice Cap, China

1988 ◽  
Vol 10 ◽  
pp. 178-182 ◽  
Author(s):  
Lonnie G. Thompson ◽  
Wu Xiaoling ◽  
Ellen Mosley-Thompson ◽  
Xie Zichu
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Average Thickness ◽  
The Past ◽  
Bedrock Topography ◽  
Ice Cap ◽  
Pulse Radar ◽  
Oxygen Isotope Ratios ◽  
Ice Core Record ◽  
Climatic Record

Results from the first glaciological investigation of the Dunde ice cap demonstrate that a long, highly temporally resolvable climatic ice-core record is preserved in this ice cap. Measurements of stratigraphy, microparticle concentrations, liquid conductivity, and oxygen-isotope ratios from three snow pits in 1984 suggest that the annual accumulation is approximately 200 mm (water equivalent). Measurement of microparticle concentrations and conductivities of pit samples collected in 1986 confirm the existence of annual dust layers and an annual accumulation rate of ∼200 mm/year over the past 5 years. Bore-hole temperatures of –5.4°C at 30 m indicate that the ice cap is polar. Mono-pulse radar depth determinations yield an average thickness of 140 m, which (coupled with the smooth bedrock topography and the current accumulation rate) suggest that the Dunde ice cap should contain at least a 3000 year climatic record. A drilling program to recover that record from this subtropical location is planned for 1987.

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