scholarly journals Physical properties of the P96 ice core from Penny Ice Cap, Baffin Island, Canada, and derived climatic records

2003 ◽  
Vol 108 (B2) ◽  
Author(s):  
Junichi Okuyama ◽  
Hideki Narita ◽  
Takeo Hondoh ◽  
Roy M. Koerner
Keyword(s):  
Physical Properties ◽  
Ice Core ◽  
Baffin Island ◽  
Ice Cap ◽  
Climatic Records

scholarly journals Structure and Flow in the Margin of the Law Dome Ice Cap. Antarctica (Abstract)

1988 ◽  
Vol 10 ◽  
pp. 222
Author(s):  
Neal W. Young
Keyword(s):  
Physical Properties ◽  
Crystal Size ◽  
Flow Line ◽  
Ice Core ◽  
Ice Cores ◽  
Crystallographic Structure ◽  
Proxy Records ◽  
Ice Cap ◽  
Radio Echo Sounding ◽  
The Law

The internal structure of the Law Dome ice cap is being investigated by studying ice cores obtained from several sites along the summit-Cape Folger line. Profiles of measured physical properties for four of the ice cores from near the margin of the ice cap are presented. A comparison of the profiles shows a gradual increase and then decrease in crystal size, and the development of strong crystal anisotropy in the upper half of the ice thickness. But in the lower part there is a complex multi-layer crystallographic structure, with an interleaving of ice which has markedly different physical properties. The development of the physical properties in the ice cores is discussed in terms of the deformation in the ice cap in the neighbourhood of the bore holes and the movement of the ice over the rough bedrock. The interdependence of the physical properties and the flow within the ice cap and their effect on other proxy records obtained from the ice cores are also explored. The Law Dome is a small ice cap, about 200 km in diameter, adjoining the main Antarctic ice sheet. It is being studied as a model ice cap, using surface surveys and ice-core drilling. It is large enough to have most of the features of larger ice sheets but small enough to be investigated in considerable detail. The four cores were drilled within 10 km of the coast at Cape Folger and lie approximately along a flow line. Each of the cores covers the Holocene and at least the later part of the Last Glacial Maximum. Two of the cores are within 40 m of bedrock and the remaining two, in thinner ice nearer the coast, are within a few metres of bedrock. Physical properties which were measured include: crystal size, texture and orientation; bubble size, orientation and distribution; and visible stratigraphy. The stratigraphy in the upper layers is related mainly to the occurrence of surface melting during the warmer months of the year. Additional supporting information is available from measurements of the physical properties on shallow cores up-stream of the four bore holes, from radio echo-sounding profiles and from other studies on the ice cores. This data is used in the discussion of the velocity field in the ice cap.

scholarly journals Glaciological Reconnaissance of an Ice Core Drilling Site, Penny Ice Cap, Baffin Island

1984 ◽  
Vol 30 (104) ◽  
pp. 3-15 ◽  
Author(s):  
G. Holdsworth
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Surface Air Temperature ◽  
Tritium Concentration ◽  
Mean Annual Temperature ◽  
Climatic Data ◽  
Baffin Island ◽  
The Core ◽  
Ice Cap ◽  
The Mean

AbstractA site situated close to the main divide of the Penny Ice Cap, Baffin Island was occupied in 1979 for the purpose of determining the suitability of this ice cap for providing proxy climatic data and other environmental time series for a span of 104a. A 20 m core was extracted and analysed for stable oxygen isotopes, tritium concentration, pH, electrolytic conductivity, major ion concentrations, and particulate concentration. An adjacent dedicated shallow core was analysed for pollen content to determine if a significant seasonal variation in the pollen rain existed. From these measurements, and from the observations made on the stratigraphic character of the core, the mean net accumulation rate over the approximately 30 year period covered by the core is found to be about 0.43 m water equivalent per year. This is in agreement with a single value determined 26 years earlier at a nearby site (Ward and Baird, 1954). The mean annual temperature in the bore hole was found to be close to −14.4° C, possibly some 2–5 deg warmer than the expected mean annual surface air temperature at the site. This difference is due to the expulsion of latent heat upon freezing of melt water at depth in the snow-pack which gives rise to the many ice layers observed in the core. The percentage thickness of ice layers per year may be correlated with summer temperatures.Total ice depths were measured using a 620 MHz radar echo-sounder. In the vicinity of the divide, over an area of 1 km2, the ice depths vary from about 460 to 515 m. These values compare favourably with values determined from an airborne radar depth-sounding flight carried out over the ice cap by a joint U.S.–Danish mission operating out of Søndre Strømfjord, Greenland. The data suggest that the ice-cap divide would be a worthwhile location to deep core drill with an expected useful coverage of at least the Holocene period.

scholarly journals An ice-core record over the last two centuries from Penny Ice Cap, Baffin Island, Canada

2002 ◽  
Vol 35 ◽  
pp. 29-35 ◽  
Author(s):  
Kumiko Goto-Azuma ◽  
Roy M. Koerner ◽  
David A. Fisher
Keyword(s):  
Environmental Changes ◽  
Ice Core ◽  
Sea Salt ◽  
Ice Age ◽  
Baffin Island ◽  
Ion Chemistry ◽  
Sea Ice Extent ◽  
The Core ◽  
Ice Cap ◽  
Ice Core Record

AbstractIn order to reconstruct climatic and environmental changes in the Canadian Arctic, an 85 m deep ice core drilled in 1995 on Penny Ice Cap, Baffin Island, was analyzed for ions and δ18O. In addition to the core, snow-pit samples collected in 1994 and 1995 were also analyzed. Elution of ions caused by summer melting was observed in the pits. Due to the heavy summer melting on this ice cap, seasonal variations of ion chemistry and δ18O were not always present in the core. Comparisons of this core with a previously reported core drilled 2.5 maway show that the noise contained in single annual time series is 40–50% for ions and 25% for δ18O. the ice-core data, however, provide us with a reasonable proxy record of climatic and environmental changes during the last two centuries on better than a decadal basis. Sulfate and nitrate concentrations started to increase around 1900 and 1960, respectively, due to anthropogenic influx transported from the industrialized regions in North America. Sea-salt concentrations began to increase around the mid-19th century and were elevated throughout the 20th century. This trend of sea-salt concentrations is similar to that of melt percentage, which is a measure of summer temperature. Warming after the Little Ice Age would have reduced the sea-ice extent and led to the elevated sea-salt concentrations on Penny Ice Cap.

Structure and Flow in the Margin of the Law Dome Ice Cap. Antarctica (Abstract)

1988 ◽  
Vol 10 ◽  
pp. 222-222
Author(s):  
Neal W. Young
Keyword(s):  
Physical Properties ◽  
Crystal Size ◽  
Flow Line ◽  
Ice Core ◽  
Ice Cores ◽  
Crystallographic Structure ◽  
Proxy Records ◽  
Ice Cap ◽  
Radio Echo Sounding ◽  
The Law

The internal structure of the Law Dome ice cap is being investigated by studying ice cores obtained from several sites along the summit-Cape Folger line. Profiles of measured physical properties for four of the ice cores from near the margin of the ice cap are presented. A comparison of the profiles shows a gradual increase and then decrease in crystal size, and the development of strong crystal anisotropy in the upper half of the ice thickness. But in the lower part there is a complex multi-layer crystallographic structure, with an interleaving of ice which has markedly different physical properties. The development of the physical properties in the ice cores is discussed in terms of the deformation in the ice cap in the neighbourhood of the bore holes and the movement of the ice over the rough bedrock. The interdependence of the physical properties and the flow within the ice cap and their effect on other proxy records obtained from the ice cores are also explored.The Law Dome is a small ice cap, about 200 km in diameter, adjoining the main Antarctic ice sheet. It is being studied as a model ice cap, using surface surveys and ice-core drilling. It is large enough to have most of the features of larger ice sheets but small enough to be investigated in considerable detail. The four cores were drilled within 10 km of the coast at Cape Folger and lie approximately along a flow line. Each of the cores covers the Holocene and at least the later part of the Last Glacial Maximum. Two of the cores are within 40 m of bedrock and the remaining two, in thinner ice nearer the coast, are within a few metres of bedrock. Physical properties which were measured include: crystal size, texture and orientation; bubble size, orientation and distribution; and visible stratigraphy. The stratigraphy in the upper layers is related mainly to the occurrence of surface melting during the warmer months of the year. Additional supporting information is available from measurements of the physical properties on shallow cores up-stream of the four bore holes, from radio echo-sounding profiles and from other studies on the ice cores. This data is used in the discussion of the velocity field in the ice cap.

scholarly journals Glaciological Reconnaissance of an Ice Core Drilling Site, Penny Ice Cap, Baffin Island

1984 ◽  
Vol 30 (104) ◽  
pp. 3-15 ◽  
Author(s):  
G. Holdsworth
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Surface Air Temperature ◽  
Tritium Concentration ◽  
Mean Annual Temperature ◽  
Climatic Data ◽  
Baffin Island ◽  
The Core ◽  
Ice Cap ◽  
The Mean

AbstractA site situated close to the main divide of the Penny Ice Cap, Baffin Island was occupied in 1979 for the purpose of determining the suitability of this ice cap for providing proxy climatic data and other environmental time series for a span of 104 a. A 20 m core was extracted and analysed for stable oxygen isotopes, tritium concentration, pH, electrolytic conductivity, major ion concentrations, and particulate concentration. An adjacent dedicated shallow core was analysed for pollen content to determine if a significant seasonal variation in the pollen rain existed. From these measurements, and from the observations made on the stratigraphic character of the core, the mean net accumulation rate over the approximately 30 year period covered by the core is found to be about 0.43 m water equivalent per year. This is in agreement with a single value determined 26 years earlier at a nearby site (Ward and Baird, 1954). The mean annual temperature in the bore hole was found to be close to −14.4° C, possibly some 2–5 deg warmer than the expected mean annual surface air temperature at the site. This difference is due to the expulsion of latent heat upon freezing of melt water at depth in the snow-pack which gives rise to the many ice layers observed in the core. The percentage thickness of ice layers per year may be correlated with summer temperatures.Total ice depths were measured using a 620 MHz radar echo-sounder. In the vicinity of the divide, over an area of 1 km2, the ice depths vary from about 460 to 515 m. These values compare favourably with values determined from an airborne radar depth-sounding flight carried out over the ice cap by a joint U.S.–Danish mission operating out of Søndre Strømfjord, Greenland. The data suggest that the ice-cap divide would be a worthwhile location to deep core drill with an expected useful coverage of at least the Holocene period.

scholarly journals Site information and initial results from deep ice drilling on Law Dome, Antarctica

1997 ◽  
Vol 43 (143) ◽  
pp. 3-10 ◽  
Author(s):  
V.I. Morgan ◽  
C.W. Wookey ◽  
J. Li ◽  
T.D. van Ommen ◽  
W. Skinner ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Sheet ◽  
High Accumulation ◽  
Ice Flow ◽  
Ice Cap ◽  
Basal Ice ◽  
Inland Ice ◽  
The Last Glacial Maximum ◽  
Initial Results ◽  
The Last Glacial

AbstractThe aim of deep ice drilling on Law Dome, Antarctica, has been to exploit the special characteristics of Law Dome summit, i.e. low temperature and high accumulation near an ice divide, to obtain a high-resolution ice core for climatic/environmental studies of the Holocene and the Last Glacial Maximum (LGM). Drilling was completed in February 1993, when basal ice containing small fragments of rock was reached at a depth of 1196 m. Accurate ice dating, obtained by counting annual layers revealed by fine-detail δ18О, peroxide and electrical-conductivity measurements, is continuous down to 399 m, corresponding to a date of AD 1304. Sulphate concentration measurements, made around depths where conductivity tracing indicates volcanic fallout, allow confirmation of the dating (for Agung in 1963 and Tambora in 1815) or estimates of the eruption date from the ice dating (for the Kuwae, Vanuatu, eruption ~1457). The lower part of the core is dated by extrapolating the layer-counting using a simple model of the ice flow. At the LGM, ice-fabric measurements show a large decrease (250 to 14 mm2) in crystal size and a narrow maximum in c-axis vertically. The main zone of strong single-pole fabrics however, is located higher up in a broad zone around 900 m. Oxygen-isotope (δ18O) measurements show Holocene ice down to 1113 m, the LGM at 1133 m and warm (δ18O) about the same as Holocene) ice near the base of the ice sheet. The LGM/Holocene δ18O shift of 7.0‰, only ~1‰ larger than for Vostok, indicates that Law Dome remained an independent ice cap and was not overridden by the inland ice sheet in the Glacial.

Ice-Core Pollen Record of Climatic Changes in the Central Andes during the last 400 yr

2005 ◽  
Vol 64 (2) ◽  
pp. 272-278 ◽  
Author(s):  
Kam-biu Liu ◽  
Carl A. Reese ◽  
Lonnie G. Thompson
Keyword(s):  
Little Ice Age ◽  
Ice Core ◽  
Climatic Changes ◽  
Ice Age ◽  
Striking Similarity ◽  
Pollen Record ◽  
Dry Period ◽  
Proxy Records ◽  
Ice Cap ◽  
Ice Accumulation

AbstractThis paper presents a high-resolution ice-core pollen record from the Sajama Ice Cap, Bolivia, that spans the last 400 yr. The pollen record corroborates the oxygen isotopic and ice accumulation records from the Quelccaya Ice Cap and supports the scenario that the Little Ice Age (LIA) consisted of two distinct phases�"a wet period from AD 1500 to 1700, and a dry period from AD 1700 to 1880. During the dry period xerophytic shrubs expanded to replace puna grasses on the Altiplano, as suggested by a dramatic drop in the Poaceae/Asteraceae (P/A) pollen ratio. The environment around Sajama was probably similar to the desert-like shrublands of the Southern Bolivian Highlands and western Andean slopes today. The striking similarity between the Sajama and Quelccaya proxy records suggests that climatic changes during the Little Ice Age occurred synchronously across the Altiplano.

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 Recession of the southern part of Barnes Ice Cap, Baffin Island, Canada, between 1961 and 1993, determined from digital mapping of Landsat TM

1997 ◽  
Vol 43 (143) ◽  
pp. 98-102 ◽  
Author(s):  
John D. Jacobs ◽  
Élizabeth L. Simms ◽  
Alvin Simms
Keyword(s):  
Regional Climate ◽  
Landsat Tm ◽  
Early 20Th Century ◽  
Baffin Island ◽  
Digital Mapping ◽  
Ice Cap ◽  
Significant Difference ◽  
Southern Half ◽  
Landsat Tm Imagery ◽  
General Reduction

AbstractChanges along the margin of the southern half of the 5900 km2 Barnes Ice Cap have been assessed using 1993 Landsat TM imagery in comparison with digitized 1:50 000 NTS maps based on 1961 photogrammetry. The average recession over the 183 km long southern perimeter was found to be at least 4 m a−1, with no significant difference between the southeast and southwest sectors. Viewed in conjunction with the sustained retreat previously reported for the northwest margin, these results indicate that a general reduction in the size of Barnes Ice Cap is occurring. The present retreat phase began under a regional climate warming in the late 19th to early 20th century period and continues, while the record of the ablation-season temperature since the mid-century has not shown any significant trend.

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