scholarly journals Distribution and characteristics of overdeepenings beneath the Greenland and Antarctic ice sheets: Implications for overdeepening origin and evolution

2016 ◽  
Vol 148 ◽  
pp. 128-145 ◽  
Author(s):  
H. Patton ◽  
D.A. Swift ◽  
C.D. Clark ◽  
S.J. Livingstone ◽  
S.J. Cook
Keyword(s):  
Ice Sheets ◽  
Origin And Evolution ◽  
Antarctic Ice Sheets

Concluding remarks

1977 ◽  
Vol 280 (972) ◽  
pp. 373-374
Keyword(s):  
Lake Sediments ◽  
Ice Sheets ◽  
The Arctic ◽  
Peat Bogs ◽  
British Isles ◽  
Field Of Study ◽  
Great Range ◽  
Scientific Disciplines ◽  
History Of ◽  
Antarctic Ice Sheets

The conclusion of this two day meeting finds us with a very great deal on which we may congratulate ourselves. In the first place there is the extremely large attendance, embracing scientists of all ages, and graced and illuminated by the attendance of many overseas colleagues of experience and distinction. In the second place we have the great range of scientific disciplines that are now applied to our field of study, many now extremely sophisticated, and the corresponding extension of Quaternary Studies into fields of evidence not hitherto exploited. In the early days of palynology of laminated lake sediments one could write of deciphering the ‘annals of the lakes’, but beginning by reading the record of lakes, peat bogs, coastal, fluviatile, glacial and periglacial geology, we have progressed to translating the long and detailed records of the deep oceans, and now the encapsulated history of the Arctic and Antarctic ice sheets. We have been introduced to the marvellous potential of the great CLIMAP Project, and all [biologists in the British Isles at least will now have to consider whether their hypotheses of past biotic history satisfy the new principle that we can all see emerging as ‘McIntyre’s Gate’.

scholarly journals Supplementary material to "Sensitivity of the Antarctic ice sheets to the peak warming of Marine Isotope Stage 11"

2020 ◽  
Author(s):  
Martim Mas e Braga ◽  
Jorge Bernales ◽  
Matthias Prange ◽  
Arjen P. Stroeven ◽  
Irina Rogozhina
Keyword(s):  
Ice Sheets ◽  
Marine Isotope Stage ◽  
Supplementary Material ◽  
The Antarctic ◽  
Antarctic Ice Sheets

Surface elevation contours of greenland and Antarctic Ice Sheets

1983 ◽  
Vol 88 (C3) ◽  
pp. 1589 ◽  
Author(s):  
H. Jay Zwally ◽  
R. A. Bindschadler ◽  
A. C. Brenner ◽  
T. V. Martin ◽  
R. H. Thomas
Keyword(s):  
Ice Sheets ◽  
Surface Elevation ◽  
Antarctic Ice Sheets

scholarly journals Screen Temperatures and 10m Temperatures

1970 ◽  
Vol 9 (56) ◽  
pp. 263-268 ◽  
Author(s):  
F. Loewe
Keyword(s):  
Air Temperature ◽  
Ice Sheets ◽  
Mean Temperature ◽  
Antarctic Ice Sheets

At places with an annual mean temperature lower than −20°C on the Greenland and Antarctic ice sheets, the temperature at a depth of 10 m is close to the annual mean at the surface and at the level of the meteorological shelter. With temperatures higher than about −35°C the size and sign of the différences vary. With lower temperatures the 10 m temperature becomes increasingly lower than the air temperature, at the coldest Antarctic station, “Plateau”, by nearly 4 deg.

scholarly journals The Greenland and Antarctic ice sheets under 1.5 °C global warming

2018 ◽  
Vol 8 (12) ◽  
pp. 1053-1061 ◽  
Author(s):  
Frank Pattyn ◽  
Catherine Ritz ◽  
Edward Hanna ◽  
Xylar Asay-Davis ◽  
Rob DeConto ◽  
...  
Keyword(s):  
Global Warming ◽  
Ice Sheets ◽  
Antarctic Ice Sheets

scholarly journals The glacial geomorphology of the Antarctic ice sheet bed

2014 ◽  
Vol 26 (6) ◽  
pp. 724-741 ◽  
Author(s):  
Stewart S.R. Jamieson ◽  
Chris R. Stokes ◽  
Neil Ross ◽  
David M. Rippin ◽  
Robert G. Bingham ◽  
...  
Keyword(s):  
Large Scale ◽  
Landscape Evolution ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Glacial Erosion ◽  
Antarctic Ice Sheet ◽  
The Past ◽  
Valley Network ◽  
The Antarctic ◽  
Antarctic Ice Sheets

AbstractIn 1976, David Sugden and Brian John developed a classification for Antarctic landscapes of glacial erosion based upon exposed and eroded coastal topography, providing insight into the past glacial dynamics of the Antarctic ice sheets. We extend this classification to cover the continental interior of Antarctica by analysing the hypsometry of the subglacial landscape using a recently released dataset of bed topography (BEDMAP2). We used the existing classification as a basis for first developing a low-resolution description of landscape evolution under the ice sheet before building a more detailed classification of patterns of glacial erosion. Our key finding is that a more widespread distribution of ancient, preserved alpine landscapes may survive beneath the Antarctic ice sheets than has been previously recognized. Furthermore, the findings suggest that landscapes of selective erosion exist further inland than might be expected, and may reflect the presence of thinner, less extensive ice in the past. Much of the selective nature of erosion may be controlled by pre-glacial topography, and especially by the large-scale tectonic structure and fluvial valley network. The hypotheses of landscape evolution presented here can be tested by future surveys of the Antarctic ice sheet bed.

scholarly journals Rapid Access Ice Drill: a new tool for exploration of the deep Antarctic ice sheets and subglacial geology

2016 ◽  
Vol 62 (236) ◽  
pp. 1049-1064 ◽  
Author(s):  
JOHN W. GOODGE ◽  
JEFFREY P. SEVERINGHAUS
Keyword(s):  
Mineral Exploration ◽  
Drill Pipe ◽  
Ice Sheets ◽  
Rapid Access ◽  
Reverse Circulation ◽  
Field Season ◽  
Pressure Compensation ◽  
Single Field ◽  
The Antarctic ◽  
Antarctic Ice Sheets

ABSTRACTA new Rapid Access Ice Drill (RAID) will penetrate the Antarctic ice sheets in order to create borehole observatories and take cores in deep ice, the glacial bed and bedrock below. RAID is a mobile drilling system to make multiple long, narrow boreholes in a single field season in Antarctica. RAID is based on a mineral exploration-type rotary rock-coring system using threaded drill pipe to cut through ice using reverse circulation of a non-freezing fluid for pressure-compensation, maintenance of temperature and removal of ice cuttings. Near the bottom of the ice sheet, a wireline latching assembly will enable rapid coring of ice, the glacial bed and bedrock below. Once complete, boreholes will be kept open with fluid, capped and available for future down-hole measurement of temperature gradient, heat flow, ice chronology and ice deformation. RAID is designed to penetrate up to 3300 m of ice and take cores in <200 hours, allowing completion of a borehole and coring in ~10 d at each site. Together, the rapid drilling capability and mobility of the system, along with ice-penetrating imaging methods, will provide a unique 3-D picture of interior and subglacial features of the Antarctic ice sheets.

scholarly journals Equatorial heat accumulation as a long-term trigger of permanent Antarctic ice sheets during the Cenozoic

2016 ◽  
Vol 113 (42) ◽  
pp. 11782-11787 ◽  
Author(s):  
Maxime Tremblin ◽  
Michaël Hermoso ◽  
Fabrice Minoletti
Keyword(s):  
Middle Eocene ◽  
Ice Sheets ◽  
Late Eocene ◽  
Equatorial Atlantic ◽  
Heat Accumulation ◽  
Climate Conditions ◽  
Driving Mechanisms ◽  
Recent Developments ◽  
Antarctic Ice Sheets

Growth of the first permanent Antarctic ice sheets at the Eocene−Oligocene Transition (EOT), ∼33.7 million years ago, indicates a major climate shift within long-term Cenozoic cooling. The driving mechanisms that set the stage for this glaciation event are not well constrained, however, owing to large uncertainties in temperature reconstructions during the Eocene, especially at lower latitudes. To address this deficiency, we used recent developments in coccolith biogeochemistry to reconstruct equatorial Atlantic sea surface temperature (SST) and atmospheric pCO2 values from pelagic sequences preceding and spanning the EOT. We found significantly more variability in equatorial SSTs than previously reported, with pronounced cooling from the Early to Middle Eocene and subsequent warming during the Late Eocene. Thus, we show that the Antarctic glaciation at the Eocene−Oligocene boundary was preceded by a period of heat accumulation in the low latitudes, likely focused in a progressively contracting South Atlantic gyre, which contributed to cooling high-latitude austral regions. This prominent redistribution of heat corresponds to the emplacement of a strong meridional temperature gradient that typifies icehouse climate conditions. Our equatorial coccolith-derived geochemical record thus highlights an important period of global climatic and oceanic upheaval, which began 4 million years before the EOT and, superimposed on a long-term pCO2 decline, drove the Earth system toward a glacial tipping point in the Cenozoic.

scholarly journals Antarctic climate and ice sheet configuration during a peak-warmth Early Pliocene interglacial

2016 ◽  
Author(s):  
Nicholas R. Golledge ◽  
Zoë A. Thomas ◽  
Richard H. Levy ◽  
Edward G. W. Gasson ◽  
Timothy R. Naish ◽  
...  
Keyword(s):  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Co2 Concentration ◽  
Geological Evidence ◽  
Early Pliocene ◽  
Air Temperatures ◽  
Climate Envelope ◽  
Global Sea Level ◽  
Antarctic Ice Sheets

Abstract. The geometry of Antarctic ice sheets during warm periods of the geological past is difficult to determine from geological evidence, but is important to know because such reconstructions enable a more complete understanding of how the ice-sheet system responds to changes in climate. Here we investigate how Antarctica evolved under orbital and greenhouse gas conditions representative of a peak warmth interglacial in the early Pliocene at 4.23 Ma. Using offline-coupled climate and ice-sheet models, together with palaeoenvironmental proxy data to define a likely climate envelope, we simulate a range of ice-sheet geometries and calculate their likely contribution to sea level. In addition, we use these simulations to investigate the processes by which the West and East Antarctic ice sheets respond to environmental forcings and the timescales over which these behaviours manifest. We conclude that the Antarctic ice sheet contributed approximately 8.5 m to global sea level at this time, under an atmospheric CO2 concentration identical to present (400 ppm). Warmer-than-present ocean temperatures led to the collapse of West Antarctica over centuries, whereas higher air temperatures initiated surface melting in parts of East Antarctica that over one to two millennia led to lowering of the ice-sheet surface, flotation of grounded margins in some areas, and retreat of the ice sheet into the Wilkes Subglacial Basin. The results show that regional variations in climate, ice-sheet geometry, and topography produce long-term sea-level contributions that are non-linear with respect to the applied forcings, and which under certain conditions exhibit threshold behaviour associated with behavioural tipping points.

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