scholarly journals High-resolution evidence for dynamic transitional geomagnetic field behaviour from a Miocene reversal, McMurdo Sound, Ross Sea, Antarctica

2007 ◽  
Vol 59 (7) ◽  
pp. 815-824 ◽  
Author(s):  
Andrew P. Roberts ◽  
Anisch Bakrania ◽  
Fabio Florindo ◽  
Christopher J. Rowan ◽  
Christopher R. Fielding ◽  
...  
Keyword(s):  
High Resolution ◽  
Geomagnetic Field ◽  
Ross Sea ◽  
Mcmurdo Sound ◽  
Field Behaviour

High-resolution paleomagnetic secular variation and relative paleointensity records from the western Canadian Arctic: implication for Holocene stratigraphy and geomagnetic field behaviourThis article is one of a series of papers published in this Special Issue on the theme Polar Climate Stability Network.GEOTOP Contribution 2008-0024.

2008 ◽  
Vol 45 (11) ◽  
pp. 1265-1281 ◽  
Author(s):  
Francesco Barletta ◽  
Guillaume St-Onge ◽  
James E.T. Channell ◽  
André Rochon ◽  
Leonid Polyak ◽  
...  
Keyword(s):  
Dipole Moment ◽  
High Resolution ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Special Issue ◽  
Polar Climate ◽  
Climate Stability ◽  
Relative Paleointensity ◽  
Holocene Stratigraphy ◽  
Field Behaviour

Two piston cores recovered from the Chukchi and the Beaufort seas document Arctic Holocene geomagnetic field behaviour and highlight the potential of secular variation and relative paleointensity as a regional chronostratigraphic tool. Several centennial- to millennial-scale Holocene declination and inclination features can be correlated in both cores, with other high-resolution western North American lacustrine and volcanic paleomagnetic records and with records of changes in Earth’s dipole moment, supporting the geomagnetic origin of these features and implying that they are associated with changes in Earth’s dipole moment.

Influence of Late Holocene climate on Lake Eggers hydrology, McMurdo Sound

2021 ◽  
pp. 1-13
Author(s):  
E.J. Chamberlain ◽  
A.J. Christ ◽  
R.W. Fulweiler
Keyword(s):  
Late Holocene ◽  
Ross Sea ◽  
Regional Climate ◽  
Ice Cores ◽  
Lake Ice ◽  
Mcmurdo Sound ◽  
Ice Accumulation ◽  
History Of ◽  
Ground Penetrating ◽  
Western Ross Sea

Abstract Ice-covered lakes in Antarctica preserve records of regional hydroclimate and harbour extreme ecosystems that may serve as terrestrial analogues for exobiotic environments. Here, we examine the impacts of hydroclimate and landscape on the formation history of Lake Eggers, a small ice-sealed lake, located in the coastal polar desert of McMurdo Sound, Antarctica (78°S). Using ground penetrating radar surveys and three lake ice cores we characterize the ice morphology and chemistry. Lake ice geochemistry indicates that Lake Eggers is fed primarily from local snowmelt that accreted onto the lake surface during runoff events. Radiocarbon ages of ice-encased algae suggest basal ice formed at least 735 ± 20 calibrated years before present (1215 C.E.). Persisting through the Late Holocene, Lake Eggers alternated between periods of ice accumulation and sublimation driven by regional climate variability in the western Ross Sea. For example, particulate organic matter displayed varying δ15N ratios with depth, corresponding to sea ice fluctuations in the western Ross Sea during the Late Holocene. These results suggest a strong climatic control on the hydrologic regime shifts shaping ice formation at Lake Eggers.

Impact of the B-15 iceberg “stranding event” on the physical and biological properties of sea ice in McMurdo Sound, Ross Sea, Antarctica

2008 ◽  
Vol 20 (6) ◽  
pp. 593-604 ◽  
Author(s):  
J.-P. Remy ◽  
S. Becquevort ◽  
T.G. Haskell ◽  
J.-L. Tison
Keyword(s):  
Sea Ice ◽  
Ross Sea ◽  
Ice Cores ◽  
Ice Cover ◽  
Biological Properties ◽  
Trophic Relationships ◽  
Oceanic Circulation ◽  
Mcmurdo Sound ◽  
Algae Biomass ◽  
Second Year

AbstractIce cores were sampled at four stations in McMurdo Sound (Ross Sea) between 1999 and 2003. At the beginning of year 2000, a very large iceberg (B-15) detached itself from the Ross Ice Shelf and stranded at the entrance of the Sound, preventing the usual oceanic circulation purging of the annual sea ice cover from this area. Ice textural studies showed that a second year sea ice cover was built-up at three out of the four stations: ice thickness increased to about 3 m. Repeated alternation of columnar and platelet ice appeared, and bulk salinity showed a strong decrease, principally in the upper part of the ice sheet, with associated brine volume decrease. Physical modification influenced the biology as well. By decreasing the light and space available for organisms in the sea ice cover, the stranding of B-15 has i) hampered autotrophic productivity, with chlorophyllaconcentration and algae biomass significantly lower for second year ice stations, and ii) affected trophic relationships such as the bacterial biomass/chlaconcentration correlation, or the autotrophic to heterotrophic ratio.

scholarly journals Geomagnetic Field Behaviour at Muntele Rosu (Romania) and Anomaly Interpretation

2019 ◽  
Vol 221 ◽  
pp. 012055 ◽  
Author(s):  
Mihai Andrei ◽  
Moldovan Iren-Adelina ◽  
Toader Victorin ◽  
Petrescu Laura ◽  
Partheniu Raluca
Keyword(s):  
Geomagnetic Field ◽  
Field Behaviour ◽  
Anomaly Interpretation

scholarly journals Structure of the poleward wall of the trough and the inclination of the geomagnetic field above the EISCAT radar

1997 ◽  
Vol 15 (6) ◽  
pp. 740-746 ◽  
Author(s):  
D. G. Jones ◽  
I. K. Walker ◽  
L. Kersley
Keyword(s):  
High Resolution ◽  
Electron Density ◽  
Time Scale ◽  
Geomagnetic Field ◽  
Energy Input ◽  
Current Model ◽  
Soft Particle ◽  
Dynamic Feature ◽  
Eiscat Radar ◽  
Good Agreement

Abstract. A special high-resolution routine of the EISCAT radar has been used to investigate the structure and development of the poleward wall of a deep trough in electron density. The feature was tracked by the radar during a 7-hour period under very quiet geomagnetic conditions. The field-aligned nature of the structure enabled an estimate to be made of the inclination of the geomagnetic field above EISCAT that was in good agreement with the current model. Observations of narrow field-aligned enhancements in electron temperature demonstrated that the wall of this trough is a dynamic feature, reforming regularly as the electron density responds on a time scale of tens of minutes to energy input from soft-particle precipitation.

A comparison of geomagnetic secular variation as recorded by historical, archaeomagnetic and palaeomagnetic measurements

1982 ◽  
Vol 306 (1492) ◽  
pp. 103-112 ◽  
Keyword(s):  
Magnetic Field ◽  
Lake Sediments ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Secular Change ◽  
Mathematical Approach ◽  
Geomagnetic Secular Variation ◽  
The Past ◽  
Palaeomagnetic Data ◽  
Field Behaviour

Palaeomagnetic methods can extend the documentary record of changes in the Earth’s magnetic field far into the past. Tolerable agreement is found between various methods, demonstrating the geophysical value of palaeomagnetic experiments. Combining results from the different approaches of investigating secular change can lead to a better perspective and to superior models of geomagnetic field behaviour. Lake sediments have recently been found to hold remarkably detailed signatures of past field changes. A mathematical approach to formulating an empirical description of global geomagnetic field behaviour is proposed and applied to palaeomagnetic data spanning the last 10 ka.

The local Last Glacial Maximum in McMurdo Sound, Antarctica: Implications for ice-sheet behavior in the Ross Sea Embayment

2019 ◽  
Vol 132 (1-2) ◽  
pp. 31-47 ◽  
Author(s):  
Andrew J. Christ ◽  
Paul R. Bierman
Keyword(s):  
Last Glacial Maximum ◽  
Ross Sea ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Significant Advance ◽  
Ice Flow ◽  
Mcmurdo Sound ◽  
Last Glacial ◽  
Transantarctic Mountains ◽  
Western Ross Sea

AbstractDuring the Last Glacial Maximum (LGM), a grounded ice sheet filled the Ross Sea Embayment in Antarctica and deposited glacial sediments on volcanic islands and peninsulas in McMurdo Sound and coastal regions of the Transantarctic Mountains. The flow geometry and retreat history of this ice are debated, with contrasting views yielding divergent implications for the interaction between and stability of the East and West Antarctic ice sheets during late Quaternary time. Here, we present terrestrial geomorphologic evidence and reconstruct former ice-marginal environments, ice sheet elevations, and ice-flow directions in McMurdo Sound. Fossil algae in ice-marginal sediments provide a coherent radiocarbon chronology of maximum ice extent and deglaciation. We integrate these data with marine records to reconstruct grounded ice dynamics in McMurdo Sound and the western Ross Sea. The combined data set suggests ice flow toward the Transantarctic Mountains in McMurdo Sound during peak glaciation, with thick, grounded ice at or near its maximum position between 19.6 and 12.3 ka. Persistent grounded ice in McMurdo Sound and across the western Ross Sea after Meltwater Pulse 1a (14.0–14.5 ka) suggests that this sector of Antarctica did not significantly contribute to this rapid sea-level rise event. Our data show no significant advance of locally derived ice from the Transantarctic Mountains into McMurdo Sound during the local LGM.

Foraging patterns of Antarctic minke whales in McMurdo Sound, Ross Sea

2020 ◽  
Vol 32 (6) ◽  
pp. 454-465
Author(s):  
David G. Ainley ◽  
Trevor W. Joyce ◽  
Ben Saenz ◽  
Robert L. Pitman ◽  
John W. Durban ◽  
...  
Keyword(s):  
Foraging Behaviour ◽  
Ross Sea ◽  
Prey Availability ◽  
Dive Depth ◽  
Remotely Operated Vehicle ◽  
Mcmurdo Sound ◽  
Minke Whales ◽  
Fast Ice ◽  
Antarctic Silverfish ◽  
Ice Edge

AbstractEvidence indicates that Antarctic minke whales (AMWs) in the Ross Sea affect the foraging behaviour, especially diet, of sympatric Adélie penguins (ADPEs) by, we hypothesize, influencing the availability of prey they have in common, mainly crystal krill. To further investigate this interaction, we undertook a study in McMurdo Sound during 2012–2013 and 2014–2015 using telemetry and biologging of whales and penguins, shore-based observations and quantification of the preyscape. The 3D distribution and density of prey were assessed using a remotely operated vehicle deployed along and to the interior of the fast-ice edge where AMWs and ADPEs focused their foraging. Acoustic surveys of prey and foraging behaviour of predators indicate that prey remained abundant under the fast ice, becoming successively available to air-breathing predators only as the fast ice retreated. Over both seasons, the ADPE diet included less krill and more Antarctic silverfish once AMWs became abundant, but the penguins' foraging behaviour (i.e. time spent foraging, dive depth, distance from colony) did not change. In addition, over time, krill abundance decreased in the upper water column near the ice edge, consistent with the hypothesis (and previously gathered information) that AMW and ADPE foraging contributed to an alteration of prey availability.

‘For the sake of science and country’: the Ross Sea party 1914–1917

Polar Record ◽  
2014 ◽  
Vol 51 (4) ◽  
pp. 343-365 ◽  
Author(s):  
David L. Harrowfield
Keyword(s):  
New Zealand ◽  
Ross Sea ◽  
Salt Water ◽  
Scientific Work ◽  
Field Work ◽  
Weddell Sea ◽  
Mcmurdo Sound ◽  
Similar Work ◽  
Glacier Ice ◽  
Meteorological Observations

ABSTRACTIn December 1913 Sir Ernest Shackleton released a prospectus and announced The Imperial Trans-Antarctic Expedition. His goal was to undertake the first crossing of Antarctica from the Weddell Sea via the polar plateau to McMurdo Sound on the Ross Sea. The journey had already been attempted by Wilhelm Filchner whose shipDeutschland, had become beset in the Weddell Sea ice for nine months in 1912. Shackleton aimed ‘to make all possible scientific observations on [the Trans-Antarctic] journey; to carry on similar work by parties operating from the two bases on the Weddell and Ross Seas [and] to carry on scientific work, and travel unknown portions of the coastline, by the two ships of the expedition’(Shackleton 1913: 3). WithEndurancea continental crossing party of six led by Shackleton would begin from the Weddell Sea and a supporting depot laying party led byNimrodveteran Lieutenant Aeneas L.A. Mackintosh RNR, with the auxiliary barquentineAurorabased in McMurdo Sound. Unbeknown to each party, both experienced problems beyond their control.Endurancewas holed and sank in the Weddell Sea andAuroralocked in ice, although damaged, reached New Zealand. Here the ship was repaired and then undertook a relief expedition with Shackleton as a passenger, to McMurdo Sound. In spite of these major setbacks each party conducted valuable scientific observations.When Shackleton published his bookSouth(Shackleton 1919) on the expedition, compiled with New Zealand journalist and friend Edward Saunders, with exception of accounts on the Ross Sea party sledging and drift of the shipAurora, no recognition was given to work undertaken by the four Ross Sea party scientists and an assistant. Later publications have focused on the depot-laying, while books on Antarctic science have largely overlooked the science undertaken.The purpose of this paper is to make this better known, and to give credit to the four scientists involved. The science conducted although primarily concerned with meteorological observations, also covers limited glaciological observations including the ablation of lake ice, solution of glacier ice in salt water, tidal recordings, collection of zoological and other specimens, along with the use of improvised equipment to undertake observations. The science achieved was secondary to the field work. The Ross Sea party science was done however, under conditions not normally conducive for such field work with health issues a major contributing factor. A lack of funding, equipment, personality problems, concern forAuroraand crew, uncertainty of Shackleton's Antarctic crossing and their own relief, led to depression, sleeplessness and insomnia.

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