Evidence of Abrupt Climatic Change During the Last 1,500 Years Recorded in Ice Cores from the Tropical Quelccaya Ice Cap, Peru

1987 ◽  
pp. 99-110 ◽  
Author(s):  
Lonnie G. Thompson ◽  
Ellen Mosley-Thompson
Keyword(s):  
Climatic Change ◽  
Ice Cores ◽  
Ice Cap ◽  
Abrupt Climatic Change ◽  
Quelccaya Ice Cap

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.

A 1500-Year Record of Tropical Precipitation in Ice Cores from the Quelccaya Ice Cap, Peru

Science ◽  
1985 ◽  
Vol 229 (4717) ◽  
pp. 971-973 ◽  
Author(s):  
L. G. THOMPSON ◽  
E. MOSLEY-THOMPSON ◽  
J. F. BOLZAN ◽  
B. R. KOCI
Keyword(s):  
Ice Cores ◽  
Tropical Precipitation ◽  
Ice Cap ◽  
Quelccaya Ice Cap

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 andβ- 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 negativeδ18O values occur during the warmer rainy season (the opposite occurs in polar regions). The near-surface meanδvalue of – 21‰ is remarkably low for this tropical site where the measured mean annual air temperature is –3°CThe seasonality of the microparticles, totalβactivity, and isotope ratios offers the prospect of a climatic ice-core record from this tropical ice cap.

Comparison of 105 Years of Oxygen Isotope and Insoluble Impurity Profiles from the Devon Island and Camp Century Ice Cores

1979 ◽  
Vol 11 (3) ◽  
pp. 299-305 ◽  
Author(s):  
David A. Fisher
Keyword(s):  
Oxygen Isotope ◽  
Flow Line ◽  
Ice Cores ◽  
Devon Island ◽  
Ice Cap ◽  
Particulate Concentration ◽  
The Difference ◽  
Impurity Profiles ◽  
Level Lowering ◽  
Present Site

Oxygen-isotope profiles for the Devon Island ice cap and Camp Century Greenland are affected by a number of variables, some of which must have been the same for both sites. The two δ(18O) records spanning about 120,000 years are brought into relative alignment by comparison of major δ features, and subsequent verification that the insoluble particulate concentration records were also in phase for this alignment. The difference between the δ profiles is shown to be mainly a function of the altitude of the accumulation area for Camp Century. This altitude seems to have been higher than present for the last 100,000 years, suggesting the present flow line through the site has never been shorter. The maximum altitude for the Camp Century accumulation area is 1500 m above the present site and is almost synchronous with the maximum in particulate concentration that occurs at 16,000 yr B.P. The synchronism is likely due to the maximum sea-level lowering that exposed vast areas of continental shelf to wind erosion.

scholarly journals The Hans Tausen drill: design, performance, further developments and some lessons learned

2007 ◽  
Vol 47 ◽  
pp. 89-98 ◽  
Author(s):  
Sigfús J. Johnsen ◽  
Steffen Bo Hansen ◽  
Simon G. Sheldon ◽  
Dorthe Dahl-Jensen ◽  
Jørgen P. Steffensen ◽  
...  
Keyword(s):  
Mechanical Design ◽  
Ice Cores ◽  
Lessons Learned ◽  
Niels Bohr ◽  
Deep Drilling ◽  
Niels Bohr Institute ◽  
Design Performance ◽  
Ice Cap ◽  
Drill Design

AbstractIn the mid-1990s, excellent results from the GRIP and GISP2 deep drilling projects in Greenland opened up funding for continued ice-coring efforts in Antarctica (EPICA) and Greenland (NorthGRIP). The Glaciology Group of the Niels Bohr Institute, University of Copenhagen, was assigned the task of providing drilling capability for these projects, as it had done for the GRIP project. The group decided to further simplify existing deep drill designs for better reliability and ease of handling. The drill design decided upon was successfully tested on Hans Tausen Ice Cap, Peary Land, Greenland, in 1995. The 5.0m long Hans Tausen (HT) drill was a prototype for the ~11m long EPICA and NorthGRIP versions of the drill which were mechanically identical to the HT drill except for a much longer core barrel and chips chamber. These drills could deliver up to 4m long ice cores after some design improvements had been introduced. The Berkner Island (Antarctica) drill is also an extended HT drill capable of drilling 2 m long cores. The success of the mechanical design of the HT drill is manifested by over 12 km of good-quality ice cores drilled by the HT drill and its derivatives since 1995.

scholarly journals The Glaciochemistry of Snow-Pits from Quelccaya Ice Cap, Peru, 1982

1985 ◽  
Vol 7 ◽  
pp. 84-88 ◽  
Author(s):  
W. Berry Lyons ◽  
A. Paul Mayewski ◽  
Lonnie G. Thompson ◽  
Boyd Allen
Keyword(s):  
Amazon Basin ◽  
Atomic Absorption Spectrophotometry ◽  
High Elevation ◽  
Common Source ◽  
Gaseous Emissions ◽  
Polar Ice ◽  
Peruvian Andes ◽  
Reactive Iron ◽  
Ice Cap ◽  
Quelccaya Ice Cap

We present glaciochemical data from a pilot study of two snow-pits from Quelccaya ice cap, Peruvian Andes. These are the first samples to be analyzed from Quelccaya for nitrate and sulfate by ion chromatography (IC), for nitrate-plus-nitrite, reactive silicate and reactive iron by colorimetry, and for sodium by atomic absorption spectrophotometry. The 3 m pits used in this study represent a one year record of mass accumulation and the 29 samples collected provide the first glaciochemical data from this area which can be compared with glaciochemical studies from other locations.Reactive iron, reactive silicate and sodium, and the profiles of >0.63μm microparticles from Thompson and others (1984) are coincident, suggesting that transport and deposition into this area of each species are controlled by similar processes. The common source is probably local, resulting from crustal weathering. In general, the reactive silicate values are lower than those observed in other alpine glacier ice. The highest sulfate and nitrate values were observed in the upper few centimeters of the snow-pit. Most of the sulfate concentrations were less than 3 μM and are similar to values obtained for fresh surface snows from Bolivia (Stallard and Edmond 1981). Since biological gaseous emissions are thought to be the major source of sulfur and nitrogen to the atmosphere over the Amazon basin, the sulfate and nitrate fluctuations may be due to seasonal biological input and/or seasonal shifts in wind direction bringing material to Quelccaya.With only one exception, the colorimetric nitrate-plus-nitrite data were higher than the IC nitrate data. Unfortunately, the IC analyses were conducted 81 d after the colorimetric analyses. The difference between the two data sets could be attributable to the following: (1) the colorimetric technique may yield erroneously high results as suggested for polar ice by Herron (1982), (2) the IC technique yields erroneously low results due, in part, to the possible exclusion of nitrite concentrations, and/or (3) nitrite was lost via biological removal during the 81 d period before the IC analyses. If the IC data are correct, the mean nitrate value is 0.4μΜ (n = 29). This value is similar to those reported from pre-industrial aged polar ice (Herron 1982). If the colorimetric mean value (1.1 μM) is correct, it is similar to colorimetrically determined values from other high-elevation alpine ice (Lyons and Mayewski 1983).

scholarly journals Thinning of the Quelccaya Ice Cap over the last thirty years

2016 ◽  
Author(s):  
C. D. Chadwell ◽  
D. R. Hardy ◽  
C. Braun ◽  
H. H. Brecher ◽  
L. G. Thompson
Keyword(s):  
Unit Volume ◽  
Environmental Changes ◽  
Statistical Significance ◽  
Geophysical Methods ◽  
Snow Accumulation ◽  
Dual Frequency ◽  
The Past ◽  
Ice Cap ◽  
Ice Surface ◽  
Quelccaya Ice Cap

Abstract. Direct measurements of the decadal response of Tropical glaciers to environmental changes are difficult to acquire within their accumulation zones. In 2013, we used dual-frequency kinematic GPS to re-measure the surface elevations at 46 sites, from the margin to across the summit of the Quelccaya Ice Cap, first measured in 1983 using terrestrial surveying methods. In 2015, six additional sites on the western margin, first observed in 1978, were remeasured. Over the past 30 years, the ice cap summit has thinned by 4.41 ± 0.23 m (2σ), with a maximum ice loss at one site near the margin of 63.4 ± 0.34 m (2σ) over 37 years. Using geophysical methods that located the sub-glacial bedrock, we estimate the unit-volume of ice in 1983 along a profile from the 1983 margin to the summit and then the change in volume from 1983 to 2013 by differencing the surface elevations. Over the past 30 years, 21.2 ± 0.3 % (2σ) of the ice unit-volume has been lost suggesting an average annual mass balance rate of −0.5 ± 0.1 m w.e. a−1 (2σ). Increasing air temperature at high elevations of the Andes is likely a major driver of the observed changes. Specifically, within the ablation zone, thinning is likely caused by a 1–2 m w.e. a−1 increase in melting and sublimation above steady-state.Within the accumulation zone, analysis of annual, dry-season summit pits suggests that surface lowering may be caused by both a slight decrease in net snow accumulation and an increase in firnification rate, though this interpretation yet lacks statistical significance. The role of ice flux changes since 1983/4 remains unconstrained, awaiting updated measurements of ice surface velocities across the ice cap.

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.

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