Tephrochronology of the Siple Dome ice core, West Antarctica: correlations and sources

2011 ◽  
Vol 30 (13-14) ◽  
pp. 1602-1614 ◽  
Author(s):  
Nelia W. Dunbar ◽  
Andrei V. Kurbatov
Keyword(s):  
Ice Core ◽  
West Antarctica ◽  
Siple Dome

Spatial variability of Antarctic surface snow glaciochemistry: implications for palaeoatmospheric circulation reconstructions

1999 ◽  
Vol 11 (1) ◽  
pp. 105-118 ◽  
Author(s):  
Karl J. Kreutz ◽  
Paul A. Mayewski
Keyword(s):  
Spatial Variability ◽  
Atmospheric Circulation ◽  
Ice Core ◽  
Chemical Concentration ◽  
West Antarctica ◽  
Transport Pathway ◽  
Amundsen Sea ◽  
Decadal Scale ◽  
Siple Dome ◽  
Surface Snow

Ice core glaciochemical records provide detailed information on past changes in atmospheric chemical composition and circulation, which is essential for understanding the timing and phasing of climatic change in different regions. Atmospheric circulation reconstructions based on these records require knowledge of modern chemical concentration controls (chemical source, transport pathway and strength) and spatial variability. To gain insight into these processes, glaciochemical data collected during reconnaissance drilling in West Antarctica combined with all other existing Antarctic surface snow glaciochemical records are examined for trends in chemical concentration vs distance inland, elevation, and accumulation rate. Snowpit data from inland West Antarctica displays significant spatial variability, suggesting complex patterns of atmospheric circulation and moisture transport in the region. Siple Dome sea-salt and methanesulphonic acid (MSA) concentrations are similar to coastal sites, suggesting enhanced advection of marine air masses to the site. Statistical analysis of a 110-year high-resolution Siple Dome ice core record confirms that strong lower tropospheric circulation dominates the region, which is most likely related to the strength of the Amundsen Sea low pressure system. An atmospheric circulation reconstruction based on the ice core glaciochemical data displays significant interannual and decadal-scale variability, but there is no overall trend in atmospheric circulation strength at Siple Dome in the past 110 years.

scholarly journals Glacial/interglacial variations in methanesulfonate (MSA) in the Siple Dome ice core, West Antarctica

2006 ◽  
Vol 33 (11) ◽  
Author(s):  
Eric S. Saltzman ◽  
Irina Dioumaeva ◽  
Brandon D. Finley
Keyword(s):  
Ice Core ◽  
West Antarctica ◽  
Siple Dome

scholarly journals A 12,000 year record of explosive volcanism in the Siple Dome Ice Core, West Antarctica

2006 ◽  
Vol 111 (D12) ◽  
Author(s):  
A. V. Kurbatov ◽  
G. A. Zielinski ◽  
N. W. Dunbar ◽  
P. A. Mayewski ◽  
E. A. Meyerson ◽  
...  
Keyword(s):  
Ice Core ◽  
Explosive Volcanism ◽  
West Antarctica ◽  
Siple Dome

scholarly journals Dating firn cores by vertical strain measurements

2002 ◽  
Vol 48 (162) ◽  
pp. 401-406 ◽  
Author(s):  
Robert L. Hawley ◽  
Edwin D. Waddington ◽  
David L. Morse ◽  
Nelia W. Dunbar ◽  
Gregory A. Zielinski
Keyword(s):  
Ice Core ◽  
Video Camera ◽  
Strain Rates ◽  
West Antarctica ◽  
Polar Ice ◽  
Vertical Strain ◽  
Ash Layer ◽  
Siple Dome ◽  
Polar Ice Sheets ◽  
Rate Profile

AbstractWe have developed a system for measuring a vertical strain-rate profile in the firn on polar ice sheets using a readily available video camera to detect metal bands inserted in an air-filled hole. We used this system in 1995 and 1996 at Taylor Dome, Antarctica. We use density measurements combined with our strain rates to infer vertical velocities. From our velocities we calculate a steady-state depth–age scale for the firn at Taylor Dome. The age of a visible ash layer from 79.1 m is 675 ± 25 years; this ash can be correlated with ash found at 97.2 m in a recent ice core at Siple Dome, West Antarctica.

scholarly journals Fabric and texture at Siple Dome, Antarctica

2005 ◽  
Vol 51 (173) ◽  
pp. 281-290 ◽  
Author(s):  
C.L. Diprinzio ◽  
L.A. Wilen ◽  
R.B. Alley ◽  
J.J. Fitzpatrick ◽  
M.K. Spencer ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Age ◽  
West Antarctica ◽  
Ice Flow ◽  
Thin Sections ◽  
Fine Grained ◽  
Additional Information ◽  
Siple Dome ◽  
History Of ◽  
Last Ice Age

AbstractPreferred c-axis orientations are present in the firn at Siple Dome, West Antarctica, and recrystallization begins as shallow as 200 m depth in ice below –20°C, based on digital analysis of c-axis fabrics, grain-sizes and other characteristics of 52 vertical thin sections prepared in the field from the kilometer-long Siple Dome ice core. The shallowest section analyzed, from 22 m, shows clustering of c axes toward the vertical. By 200 m depth, girdle fabric and other features of recrystallized ice are evident in layers (or regions), separated by layers (regions) of typically finer-grained ice lacking evidence of recrystallization. Ice from about 700–780m depth, which was deposited during the last ice age, is especially fine-grained, with strongly vertical c axes, but deeper ice shows much larger crystals and strong evidence of recrystallization. Azimuthal asymmetry of some c-axis fabrics, trends in grain-size, and other indicators reveal additional information on processes and history of ice flow at Siple Dome.

scholarly journals Physical properties, crystalline textures and c-axis fabrics of the Siple Dome (Antarctica) ice core

2007 ◽  
Vol 53 (183) ◽  
pp. 573-584 ◽  
Author(s):  
Anthony J. Gow ◽  
Debra Meese
Keyword(s):  
Ice Core ◽  
West Antarctica ◽  
Ice Streams ◽  
Major Transitions ◽  
The Core ◽  
Siple Dome ◽  
Brittle Zone ◽  
Shear Type ◽  
Sudden Appearance ◽  
Rock Interface

The quality of the ice core from Siple Dome, West Antarctica, varied widely, with significant fracturing below 400 m. Bubbly ice persisted to the ice–rock interface at 1004 m and constituted the brittle zone. The core has undergone minimal relaxation and has remained brittle and prone to fracturing more than 5 years after it was drilled. This behavior is attributed to unrelieved stresses from Kamb and Bindschadler Ice Streams (former Ice Streams C and D) flanking the dome. Melt layers were identified sporadically throughout the core, as were inclined layers tilted at angles that occasionally exceeded 10°. Structurally, the ice was characterized by extensive recrystallization including grain-size changes from 0.074 cm2 at 59 m to >50 cm2 at 992 m, and major transitions in c-axis fabrics. Unusual fabrics included vertical c-axis clusters superimposed on vertical girdles that may reflect vertical compression acting in conjunction with horizontal tension. The sudden appearance of a shear-type fabric at 700–800 m appears closely linked to the occurrence of abundant tephra particles embedded in the ice. The occurrence of dispersed sediment in the bottom 2 m is attributed to freeze-on of basal meltwater.

scholarly journals The Amundsen Sea Low: Variability, Change, and Impact on Antarctic Climate

2016 ◽  
Vol 97 (1) ◽  
pp. 111-121 ◽  
Author(s):  
M. N. Raphael ◽  
G. J. Marshall ◽  
J. Turner ◽  
R. L. Fogt ◽  
D. Schneider ◽  
...  
Keyword(s):  
Sea Ice ◽  
Climate Model ◽  
Ross Sea ◽  
Ice Core ◽  
Meridional Wind ◽  
West Antarctica ◽  
Sea Ice Extent ◽  
Amundsen Sea ◽  
West Antarctic ◽  
Climate Model Simulations

Abstract The Amundsen Sea low (ASL) is a climatological low pressure center that exerts considerable influence on the climate of West Antarctica. Its potential to explain important recent changes in Antarctic climate, for example, in temperature and sea ice extent, means that it has become the focus of an increasing number of studies. Here, the authors summarize the current understanding of the ASL, using reanalysis datasets to analyze recent variability and trends, as well as ice-core chemistry and climate model projections, to examine past and future changes in the ASL, respectively. The ASL has deepened in recent decades, affecting the climate through its influence on the regional meridional wind field, which controls the advection of moisture and heat into the continent. Deepening of the ASL in spring is consistent with observed West Antarctic warming and greater sea ice extent in the Ross Sea. Climate model simulations for recent decades indicate that this deepening is mediated by tropical variability while climate model projections through the twenty-first century suggest that the ASL will deepen in some seasons in response to greenhouse gas concentration increases.

scholarly journals Supplementary material to "Mineral Dust Influence on the Glacial Nitrate Record from the RICE Ice Core, West Antarctica and Environmental Implications"

2020 ◽  
Author(s):  
Abhijith U. Venugopal ◽  
Nancy A. N. Bertler ◽  
Rebecca L. Pyne ◽  
Helle A. Kjær ◽  
V. Holly L. Winton ◽  
...  
Keyword(s):  
Mineral Dust ◽  
Ice Core ◽  
West Antarctica ◽  
Environmental Implications ◽  
Supplementary Material

scholarly journals A 2700-year annual timescale and accumulation history for an ice core from Roosevelt Island, West Antarctica

2017 ◽  
Author(s):  
Mai Winstrup ◽  
Paul Vallelonga ◽  
Helle A. Kjær ◽  
Tyler J. Fudge ◽  
James E. Lee ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Early Period ◽  
Volcanic Eruptions ◽  
Snow Accumulation ◽  
Atmospheric Methane ◽  
Accumulation Rates ◽  
West Antarctica ◽  
Ross Ice Shelf ◽  
Accumulation History

Abstract. We present a 2700-year annually resolved timescale for the Roosevelt Island Climate Evolution (RICE) ice core, and reconstruct a past snow accumulation history for the coastal sector of the Ross Ice Shelf in West Antarctica. The timescale was constructed by identifying annual layers in multiple ice-core impurity records, employing both manual and automated counting approaches, and constitutes the top part of the Roosevelt Island Ice Core Chronology 2017 (RICE17). The maritime setting of Roosevelt Island results in high sulfate influx from sea salts and marine biogenic emissions, which prohibits a routine detection of volcanic eruptions in the ice-core records. This led to the use of non-traditional chronological techniques for validating the timescale: RICE was synchronized to the WAIS Divide ice core, on the WD2014 timescale, using volcanic attribution based on direct measurements of ice-core acidity, as well as records of globally-synchronous, centennial-scale variability in atmospheric methane concentrations. The RICE accumulation history suggests stable values of 0.25 m water equivalent (w.e.) per year until around 1260 CE. Uncertainties in the correction for ice flow thinning of annual layers with depth do not allow a firm conclusion about long-term trends in accumulation rates during this early period but from 1260 CE to the present, accumulation rate trends have been consistently negative. The decrease in accumulation rates has been increasingly rapid over the last centuries, with the decrease since 1950 CE being more than 7 times greater than the average over the last 300 years. The current accumulation rate of 0.22 ± 0.06 m w.e. yr−1 (average since 1950 CE, ±1σ) is 1.49 standard deviations (86th percentile) below the mean of 50-year average accumulation rates observed over the last 2700 years.

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