Chapter 6.1 Marine record of Antarctic volcanism from drill cores

AbstractWe review here data and information on Antarctic volcanism resulting from recent tephrostratigraphic investigations on marine cores. Records include deep drill cores recovered during oceanographic expeditions: DSDP, ODP and IODP drill cores recovered during ice-based and land-based international cooperative drilling programmes DVDP 15, MSSTS-1, CIROS-1 and CIROS-2, DVDP 15, CRP-1, CRP-2/2A and CRP-3, ANDRILL-MIS and ANDRILL-SMS, and shallow gravity and piston cores recovered in the Antarctic and sub-Antarctic oceans. We report on the identification of visible volcaniclastic horizons and, in particular, of primary tephra within the marine sequences. Where available, the results of analyses carried out on these products are presented. The volcanic material identified differs in its nature, composition and emplacement mechanisms. It was derived from different sources on the Antarctic continent and was emplaced over a wide time span.Marine sediments contain a more complete record of the explosive activity from Antarctic volcanoes and are complementary to those obtained by land-based studies. This record provides important information for volcanological reconstructions including approximate intensities and magnitudes of eruptions, and their duration, age and recurrence, as well as their eruptive dynamics. In addition, characterized tephra layers represent an invaluable chronological tool essential in establishing correlations between different archives and in synchronizing climate records.

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Chapter 7.4 Active volcanoes in Marie Byrd Land

Geological Society London Memoirs ◽

10.1144/m55-2019-29 ◽

2021 ◽

pp. M55-2019-29

Author(s):

N. W. Dunbar ◽

N. A. Iverson ◽

J. L. Smellie ◽

W. C. McIntosh ◽

M. J. Zimmerer ◽

...

Keyword(s):

Activity Patterns ◽

Ice Cores ◽

Time Span ◽

Geochemical Evolution ◽

Time Interval ◽

Single Source ◽

Explosive Activity ◽

Partial Melt ◽

The Past ◽

Tephra Layers

AbstractTwo volcanoes in Marie Byrd Land, Mount Berlin and Mount Takahe, can be considered active, and a third, Mount Waesche, may be as well; although the chronology of activity is less well constrained. The records of explosive activity of these three volcanoes is well represented through deposits on the volcano flanks and tephra layers found in blue ice areas, as well as by the presence of cryptotephra layers found in West and East Antarctic ice cores. Records of effusive volcanism are found on the volcano flanks but some deposits may be obscured by pervasive glacerization of the edifices. Based on a compilation of tephra depths–ages in ice cores, the activity patterns of Mount Takahe and Mount Berlin are dramatically different. Mount Takahe has erupted infrequently over the past 100 kyr. Mount Berlin, by contrast, has erupted episodically during this time interval, with the number of eruptions being dramatically higher in the time interval between c. 32 and 18 ka. Integration of the Mount Berlin tephra record from ice cores and blue ice areas over a 500 kyr time span reveals a pattern of geochemical evolution related to small batches of partial melt being progressively removed from a single source underlying Mount Berlin.

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Lichens of the Oasis Molodyozhnyi and adjacent areas (Enderby Land, Antarctic)

Novosti sistematiki nizshikh rastenii ◽

10.31111/nsnr/2013.47.167 ◽

2013 ◽

Vol 47 ◽

pp. 167-178 ◽

Cited By ~ 1

Author(s):

M. P. Andreev

Keyword(s):

Liquid Water ◽

Climate Conditions ◽

Water Ice ◽

Buellia Frigida ◽

Antarctic Continent ◽

Harsh Climate ◽

The Antarctic ◽

First Time ◽

Lichen Flora

Lichen flora and vegetation in the vicinity of the Russian base «Molodyozhnaya» (Enderby Land, Antarctica) were investigated in 2010–2011 in details for the first time. About 500 specimens were collected in 100 localities in all available ecotopes. The lichen flora is the richest in the region and numbers 39 species (21 genera, 11 families). The studied vegetation is very poor and sparse, but typical for coastal oases of the Antarctic continent. The poorness is caused by the extremely harsh climate conditions, insufficient availability of liquid water, ice-free land, and high insolation levels. The dominant and most common lichens are Rinodina olivaceobrunnea, Amandinea punctata, Candelariella flava, Physcia caesia, Caloplaca tominii, Lecanora expectans, Caloplaca ammiospila, Lecidea cancriformis, Pseudephebe minuscula, Lecidella siplei, Umbilicaria decussata, Buellia frigida, Lecanora fuscobrunnea, Usnea sphacelata, Lepraria and Buellia spp.

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The Complete Guide to Antarctic Wildlife: Birds and Marine Mammals of the Antarctic Continent and the Southern Ocean. By Hadoram Shirihai; illustrated by Brett Jarrett. Princeton (New Jersey): Princeton University Press. $49.50. 510 p; ill.; index. ISBN: 0‐691‐11414‐5. 2002.

The Quarterly Review of Biology ◽

10.1086/380030 ◽

2003 ◽

Vol 78 (3) ◽

pp. 364-365

Author(s):

Charles F Wurster

Keyword(s):

New Jersey ◽

Southern Ocean ◽

Marine Mammals ◽

Princeton University ◽

Antarctic Continent ◽

The Antarctic

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Accuracy Analysis of International Reference Ionosphere 2016 and NeQuick2 in the Antarctic

Sensors ◽

10.3390/s21041551 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1551

Author(s):

Zihuai Guo ◽

Yibin Yao ◽

Jian Kong ◽

Gang Chen ◽

Chen Zhou ◽

...

Keyword(s):

Solar Radiation ◽

International Reference Ionosphere ◽

Electron Content ◽

Observation Data ◽

Dual Frequency ◽

Total Electron ◽

International Reference ◽

Antarctic Continent ◽

The Antarctic ◽

Frequency Observation

Global navigation satellite system (GNSS) can provide dual-frequency observation data, which can be used to effectively calculate total electron content (TEC). Numerical studies have utilized GNSS-derived TEC to evaluate the accuracy of ionospheric empirical models, such as the International Reference Ionosphere model (IRI) and the NeQuick model. However, most studies have evaluated vertical TEC rather than slant TEC (STEC), which resulted in the introduction of projection error. Furthermore, since there are few GNSS observation stations available in the Antarctic region and most are concentrated in the Antarctic continent edge, it is difficult to evaluate modeling accuracy within the entire Antarctic range. Considering these problems, in this study, GNSS STEC was calculated using dual-frequency observation data from stations that almost covered the Antarctic continent. By comparison with GNSS STEC, the accuracy of IRI-2016 and NeQuick2 at different latitudes and different solar radiation was evaluated during 2016–2017. The numerical results showed the following. (1) Both IRI-2016 and NeQuick2 underestimated the STEC. Since IRI-2016 utilizes new models to represent the F2-peak height (hmF2) directly, the IRI-2016 STEC is closer to GNSS STEC than NeQuick2. This conclusion was also confirmed by the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) occultation data. (2) The differences in STEC of the two models are both normally distributed, and the NeQuick2 STEC is systematically biased as solar radiation increases. (3) The root mean square error (RMSE) of the IRI-2016 STEC is smaller than that of the NeQuick2 model, and the RMSE of the two modeling STEC increases with solar radiation intensity. Since IRI-2016 relies on new hmF2 models, it is more stable than NeQuick2.

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Dimethysulfide concentrations in the ocean close to the antarctic continent

Geomicrobiology Journal ◽

10.1080/01490458809377837 ◽

1988 ◽

Vol 6 (3-4) ◽

pp. 179-184 ◽

Cited By ~ 19

Author(s):

John A.E. Gibson ◽

Russell C. Garrick ◽

Harry R. Burton ◽

Andrew R. McTaggart

Keyword(s):

Antarctic Continent ◽

The Antarctic

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Chemical Composition of Ice Containing Tephra Layers in the Byrd Station Ice Core, Antarctica

Quaternary Research ◽

10.1016/0033-5894(88)90007-5 ◽

1988 ◽

Vol 30 (3) ◽

pp. 315-330 ◽

Cited By ~ 9

Author(s):

Julie M. Palais ◽

Philip R. Kyle

Keyword(s):

Chemical Composition ◽

Silicate Glass ◽

Residence Time ◽

Volcanic Ash ◽

Global Climate ◽

Ice Core ◽

Volcanic Eruptions ◽

Tephra Layers ◽

The Antarctic ◽

Hydrolysis Of

The chemical composition of ice containing tephra (volcanic ash) layers in 22 sections of the Byrd Station ice core was examined to determine if the volcanic eruptions affected the chemical composition of the atmosphere and precipitation in the vicinity of Byrd Station. The liquid conductivity, acidity, sulfate, nitrate, aluminum, and sodium concentrations of ice samples deposited before, during, and after the deposition of the tephra layers were analyzed. Ice samples that contain tephra layers have, on average, about two times more sulfate and three to four times more aluminum than nonvolcanic ice samples. The acidity of ice samples associated with tephra layers is lowered by hydrolysis of silicate glass and minerals. Average nitrate, sodium, and conductivity are the same in all samples. Because much of the sulfur and chlorine originally associated with these eruptions may have been scavenged by ash particles, the atmospheric residence time of these volatiles would have been minimized. Therefore the eruptions probably had only a small effect on the composition of the Antarctic atmosphere and a negligible effect on local or global climate.

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Soil tardigrades from the Antarctic Peninsula with a description of a new species and some remarks on the genusRamajendas(Eutardigrada: Isohypsibiidae)

Polar Record ◽

10.1017/s0032247413000168 ◽

2013 ◽

Vol 50 (2) ◽

pp. 176-182 ◽

Cited By ~ 8

Author(s):

Łukasz Kaczmarek ◽

Karel Janko ◽

Jerzy Smykla ◽

Łukasz Michalczyk

Keyword(s):

New Species ◽

Antarctic Peninsula ◽

Morphometric Characters ◽

Antarctic Continent ◽

Fourth Species ◽

The Antarctic ◽

A New Species ◽

Mixed Samples ◽

Hypsibius Dujardini

ABSTRACTIn thirteen (mostly soil) mixed samples, collected from nine localities on the Antarctic continent and some of the neighbouring islands, 788 specimens and 32 eggs of tardigrades were found. In total, five species were identified:Acutuncus antarcticus, Echiniscus jenningsi,Diphascon(D.)victoriae,Hypsibius dujardiniandRamajendas dastychisp. nov.A. antarcticuswas the most abundant (nearly 90% of all specimens) and was the prevailing taxon found in the majority of locations.R. dastychisp. nov. is the fourth species described in the exclusively Antarctic/sub-Antarctic genus. The new species differs from all other congeners by the presence of four gibbosities on the caudo-dorsal cuticle (configuration II:2–2) and also by some morphometric characters. In this paper we also briefly discuss the taxonomy and zoogeography of the genusRamajendas.

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Life history strategy of Lepraria borealis at an Antarctic inland site, Coal Nunatak

The Lichenologist ◽

10.1017/s0024282909990600 ◽

2010 ◽

Vol 42 (3) ◽

pp. 339-346 ◽

Cited By ~ 12

Author(s):

Andreas ENGELEN ◽

Peter CONVEY ◽

Sieglinde OTT

Keyword(s):

Life History ◽

Environmental Conditions ◽

Life History Strategy ◽

Sequence Polymorphism ◽

Internal Transcribed Spacer Region ◽

The West ◽

Distinctive Features ◽

Dna Sequence Polymorphism ◽

Antarctic Continent ◽

The Antarctic

AbstractCoal Nunatak is an ice-free inland nunatak located on southern Alexander Island, adjacent to the west coast of the Antarctic Peninsula. Situated close to the Antarctic continent, it is characterized by harsh environmental conditions. Macroscopic colonization is restricted to micro-niches offering suitable conditions for a small number of lichens and mosses. The extreme environmental conditions place particular pressures on colonizers. Lepraria borealis is the dominant crustose lichen species present on Coal Nunatak, and shows distinctive features in its life history strategy, in particular expressing unusually low selectivity of the mycobiont towards potential photobionts. To assess selectivity, we measured algal DNA sequence polymorphism in a region of 480–660 bp of the nuclear internal transcribed spacer region of ribosomal DNA. We identified three different photobiont species, belonging to two different genera. We interpret this strategy as being advantageous in facilitating the colonization and community dominance of L. borealis under the isolation and extreme environmental conditions of Coal Nunatak.

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On the thickness of the Antarctic ice, and its relations to that of the glacial epoch

Earth and Environmental Science Transactions of the Royal Society of Edinburgh ◽

10.1017/s1755691021000050 ◽

2021 ◽

pp. 1-8

Author(s):

James CROLL ◽

David SUGDEN

Keyword(s):

Thermal Regime ◽

Freezing Point ◽

Ice Sheet ◽

Heat Sources ◽

Mean Velocity ◽

Point Estimates ◽

Glacial Epoch ◽

Antarctic Continent ◽

Global Sea Level ◽

The Antarctic

ABSTRACT At a time when nobody has yet landed on the Antarctic continent (1879), this presentation and accompanying paper predicts the morphology, dynamics and thermal regime of the Antarctic ice sheet. Mathematical modelling of the ice sheet is based on the assumptions that the thickness of tabular icebergs reflects the average thickness of the ice at the margin and that the surface gradients are comparable to those of reconstructed former ice sheets in the Northern Hemisphere. The modelling shows that (a) ice is thickest near the centre at the South Pole and thins towards the margin; (b) the thickness at the pole is independent of the amount of snowfall at that place; and (c) the mean velocity at the margin, assuming a mean annual snowfall of two inches per year, is 400–500 feet per year. The thermal regime of the ice sheet is influenced by three heat sources – namely, the bed, the internal friction of ice flow and the atmosphere. The latter is the most significant and, since ice has a downwards as well as horizontal motion, this carries cold ice down into the ice sheet. Since the temperature at which ice melts is lowered by pressure at a rate of 0.0137 °F for every atmosphere of pressure (something known since 1784), much of the ice sheet and its base must be below the freezing point. Estimates of the thickness of ice at the centre depend closely on the surface gradients assumed and range between 3 and 24 miles. Such uncertainty is of concern since both the volume and gravitational attraction of the ice mass have an effect on global sea level. In order to improve our estimate of the volume of ice, we will have to wait 76 years for John Glen to develop a realistic flow law for ice.

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Pathways and timescales of connectivity around the Antarctic continental shelf

10.5194/egusphere-egu21-14011 ◽

2021 ◽

Author(s):

Hannah Dawson ◽

Adele Morrison ◽

Veronica Tamsitt ◽

Matthew England

Keyword(s):

Continental Shelf ◽

Ross Sea ◽

Coastal Current ◽

West Antarctica ◽

Source Regions ◽

Freshwater Forcing ◽

Antarctic Continental Shelf ◽

Antarctic Continent ◽

Antarctic Slope Current ◽

The Antarctic

The Antarctic margin is surrounded by two westward flowing currents: the Antarctic Slope Current and the Antarctic Coastal Current. The former influences key processes near the Antarctic margin by regulating the flow of heat and nutrients onto and off the continental shelf, while together they advect nutrients, biological organisms, and temperature and salinity anomalies around the coastline, providing a connective link between different shelf regions. However, the extent to which these currents transport water from one sector of the continental shelf to another, and the timescales over which this occurs, remain poorly understood. Concern that crucial water formation sites around the Antarctic coastline could respond to non-local freshwater forcing from ice shelf meltwater motivates a more thorough understanding of zonal connectivity around Antarctica. In this study, we use daily velocity fields from a global high-resolution ocean-sea ice model, combined with the Lagrangian tracking software Parcels, to investigate the pathways and timescales connecting different regions of the Antarctic continental shelf with a view to understanding the timescales of meltwater transport around the continent. Virtual particles are released over the continental shelf, poleward of the 1000 metre isobath, and are tracked for 20 years. Our results show a strong seasonal cycle connecting different sectors of the Antarctic continent, with more particles arriving further downstream during winter than during summer months. Strong advective links exist between West Antarctica and the Ross Sea while shelf geometry in some other regions acts as barriers to transport. We also highlight the varying importance of the Antarctic Slope Current and Antarctic Coastal Current in connecting different sectors of the coastline. Our results help to improve our understanding of circum-Antarctic connectivity and the timescales of meltwater transport from source regions to downstream shelf locations. Furthermore, the timescales and pathways we present provide a baseline from which to assess long-term changes in Antarctic coastal circulation due to local and remote forcing.

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