scholarly journals Technical procedures for aeromagnetic surveys in Antarctica during the Italian expeditions (1988-1992)

1994 ◽  
Vol 37 (5 Sup.) ◽  
Author(s):  
E. Bozzo ◽  
A. Colla ◽  
G. Caneva ◽  
A. Meloni ◽  
A. Caramelli ◽  
...  
Keyword(s):  
Ross Sea ◽  
Base Stations ◽  
Aeromagnetic Survey ◽  
The North ◽  
Terra Nova Bay ◽  
Victoria Land ◽  
Range Type ◽  
Line Spacing ◽  
Tie Lines ◽  
Shelf Region

For most of Antarctica, the geophysical data now available are those of aeromagnetic surveys performed there from 1950 to 1960. Until 1984, the inaccurate positioning and insufficient monitoring of geomagnetic time variations allowed the investigation of the geomagnetic residual field only along profiles. The Ganovex IV aeromagnetic survey, performed by BGR-USGS over the Ross Sea and the Northern Victoria Land, and the geophysical investigations of BAS on the Southern Antarctic peninsula and the Ronne ice shelf region corresponds to the recent advancement of these techniques in Antarctica. The first experiments of aeromagnetic measurements, during the Italian expeditions in Antarctica were made during the 1988-1989 field season. Some geomagnetic helicopter borne profiles were accomplished with a Proton Precession Magnetometer (PPM) in the Terra Nova Bay-Gerlache Inlet area. In the 1989-1990 ItaliAntartide expedition some profiles were flown over the suture between the Wilson and Bower terranes, in Northern Victoria Land. During the 1991-1992 expedition, in cooperation with researchers of BGR (Bundesanstalt fur Geowissenschaften und Rohstoffe) of Hannover, the GITARA I (German ITalian Aeromagnetic Rescarch Antarctica) program, as part of the LIRA (Litospheric Investigation in the Ross Sea Area) project, was carried out. The investigated area lies between the latitudes 74°18' S and 75°18' S and the longitudes 160°30' E and 164°30'E and it corresponds to a portion of the North Victoria Land, located between the Eisenhower Range and the, DrygaIski Ice Tongue. The survey was made with a Cesium vapour magnetometer. The positioning system was of the “Range-Range” type, it consisted of three transmitters (beacons), installed inside the investigated area and located with GPS measurements. The line spacing was 4.4 km, with tie lines every 22 km. The survey covered an area of 6500 km2 . Four PPM base stations for the determination of the time variation corrections were installed. The aeromagnetic anomalies wilI allow the comparison with the ground geomagnetic surveys performed during the previous Antarctic expeditions, also in connection with the aeromagnetic maps of Ganovex IV, located at the northern and eastern boundaries of the GITARA area.

Significance of selected halocarbons monitoring in air samples collected in the Terra Nova Bay region (northern Victoria Land, Antarctica)

1999 ◽  
Vol 11 (2) ◽  
pp. 261-264 ◽  
Author(s):  
Filippo Mangani ◽  
Michela Maione ◽  
Luciano Lattanzi
Keyword(s):  
Ross Sea ◽  
Atmospheric Concentration ◽  
Air Samples ◽  
Terra Nova Bay ◽  
Victoria Land ◽  
Rate Of Increase ◽  
Terra Nova ◽  
Concentration Levels

CCl3F (or CFC-11) and CCl2F2 (or CFC-12) were determined in air samples collected, during subsequent summer Antarctic campaigns, in different sampling sites in the Ross Sea Region. The samples were analysed by GC-ECD after enrichment. Data obtained since 1988–89 were plotted to observe the trend of CFCs atmospheric concentration levels. A decrease in the rate of increase of CFC-12 concentration was observed, whilst the concentration of CFC-11 was actually seen to be decreasing.

Pre-LGM open-water conditions south of the Drygalski Ice Tongue, Ross Sea, Antarctica

2007 ◽  
Vol 19 (3) ◽  
pp. 373-377 ◽  
Author(s):  
Furio Finocchiaro ◽  
Carlo Baroni ◽  
Ester Colizza ◽  
Roberta Ivaldi
Keyword(s):  
Ross Sea ◽  
Open Water ◽  
Radiocarbon Dates ◽  
The Core ◽  
Bay Area ◽  
Terra Nova Bay ◽  
Insoluble Organic Matter ◽  
Victoria Land ◽  
Marine Isotope Stage 3 ◽  
Raised Beaches

AbstractA marine sediment core collected from the Nordenskjold Basin, to the south of the Drygalski Ice Tongue, provides new sedimentological and chronological data for reconstructing the Pleistocene glacial history and palaeoenvironmental evolution of Victoria Land. The core consists of an over consolidated biogenic mud covered with glacial diamicton; Holocene diatomaceous mud lies on top of the sequence. Radiocarbon dates of the acid insoluble organic matter indicate a pre-Last Glacial Maximum age (>24kyr) for the biogenic mud at the base of the sequence. From this we can presume that at least this portion of the western Ross Sea was deglaciated during Marine Isotope Stage 3 and enjoyed open marine conditions. Our results are consistent with recent findings of pre-Holocene raised beaches at Cape Ross and in the Terra Nova Bay area.

scholarly journals Genetic diversity among populations of Antarctic springtails (Collembola) within the Mackay Glacier ecotone

Genome ◽  
2016 ◽  
Vol 59 (9) ◽  
pp. 762-770 ◽  
Author(s):  
Clare R. Beet ◽  
Ian D. Hogg ◽  
Gemma E. Collins ◽  
Don A. Cowan ◽  
Diana H. Wall ◽  
...  
Keyword(s):  
Climate Changes ◽  
Ross Sea ◽  
Sequence Divergence ◽  
Running Waters ◽  
The North ◽  
Victoria Land ◽  
The Reformation ◽  
Springtail Species ◽  
Biogeographic Regions ◽  
Coi Sequences

Climate changes are likely to have major influences on the distribution and abundance of Antarctic terrestrial biota. To assess arthropod distribution and diversity within the Ross Sea region, we examined mitochondrial DNA (COI) sequences for three currently recognized species of springtail (Collembola) collected from sites in the vicinity, and to the north of, the Mackay Glacier (77°S). This area acts as a transition between two biogeographic regions (northern and southern Victoria Land). We found populations of highly divergent individuals (5%–11.3% intraspecific sequence divergence) for each of the three putative springtail species, suggesting the possibility of cryptic diversity. Based on molecular clock estimates, these divergent lineages are likely to have been isolated for 3–5 million years. It was during this time that the Western Antarctic Ice Sheet (WAIS) was likely to have completely collapsed, potentially facilitating springtail dispersal via rafting on running waters and open seaways. The reformation of the WAIS would have isolated newly established populations, with subsequent dispersal restricted by glaciers and ice-covered areas. Given the currently limited distributions for these genetically divergent populations, any future changes in species’ distributions can be easily tracked through the DNA barcoding of springtails from within the Mackay Glacier ecotone.

scholarly journals An Analysis of Low-Level Jets in the Greater Ross Ice Shelf Region Based on Numerical Simulations

2008 ◽  
Vol 136 (11) ◽  
pp. 4188-4205 ◽  
Author(s):  
Mark W. Seefeldt ◽  
John J. Cassano
Keyword(s):  
Wind Speed ◽  
Ross Sea ◽  
Ice Shelf ◽  
Self Organizing Maps ◽  
Low Level ◽  
Ross Ice Shelf ◽  
The North ◽  
Low Level Jets ◽  
Shelf Region ◽  
Strong Seasonality

Abstract An analysis of the presence and location of low-level jets (LLJs) across the Ross Ice Shelf region in Antarctica is presented based on the analysis of archived output from the real-time Antarctic Mesoscale Prediction System (AMPS). The method of self-organizing maps (SOMs) is used to objectively identify different patterns in column-averaged wind speed (over the approximately lowest 1200 m of the atmosphere) as an identifier to the location of LLJs. The results indicate three primary LLJs in the region. The largest and most dominant LLJ is along the Transantarctic Mountains by the Siple Coast and the southern end of the Ross Ice Shelf. The second LLJ extends from the base of Byrd Glacier and curves to the north passing by the eastern extremes of Ross Island. The third LLJ extends from the base of Reeves Glacier and curves to the north across the western Ross Sea. A strong seasonality is observed in the frequency and intensity of the LLJs with the highest values for wind speed and the size of the LLJ at a maximum during the winter and spring months.

Transfer faults in the western Ross Sea: new evidence from the McMurdo Sound/Ross Ice Shelf aeromagnetic survey (GANOVEX VI)

1994 ◽  
Vol 6 (3) ◽  
pp. 359-364 ◽  
Author(s):  
D. Damaske ◽  
J. Behrendt ◽  
A. McCafferty ◽  
R. Saltus ◽  
U. Meyer
Keyword(s):  
Ross Sea ◽  
Rift System ◽  
Ice Shelf ◽  
Aeromagnetic Survey ◽  
Southern Boundary ◽  
Ross Ice Shelf ◽  
The North ◽  
West Antarctic ◽  
Transfer Faults ◽  
Western Ross Sea

Aeromagnetic data collected on the GANOVEX IV and GANOVEX VI expeditions are combined in this report to give a synoptic view of the western Ross Sea, Antarctica. The addition of the new GANOVEX VI data allows the identification of the southern boundary of the “Ross Sea Unit” — a magnetic unit containing rift-fabric anomalies of the West Antarctic rift system in the Victoria Land basin. Although this boundary has a similar WSW–ENE orientation to the northern boundary, as identified in the GANOVEX IV survey, the newly identified southern magnetic unit (called the “Ross Island and Ice Shelf Edge Unit”) includes evidence of the S–N rift-fabric that is not found in the north, i.e. the rift-fabric continues farther south. The linear boundaries themselves are interpreted as transfer faults as proposed by previous workers for the tectonic development of the Ross Sea area.

scholarly journals The influence of the Drygalski Ice Tongue on the local ocean

2017 ◽  
Vol 58 (74) ◽  
pp. 51-59 ◽  
Author(s):  
Craig Stevens ◽  
Won Sang Lee ◽  
Giannetta Fusco ◽  
Sukyoung Yun ◽  
Brett Grant ◽  
...  
Keyword(s):  
Vertical Structure ◽  
High Salinity ◽  
Cold Water ◽  
Ross Sea ◽  
Coastal Current ◽  
Terra Nova Bay ◽  
Victoria Land ◽  
Ocean Region ◽  
Oceanographic Data ◽  
Western Ross Sea

ABSTRACT The Drygalski Ice Tongue presents an ~80 km long floating obstacle to alongshore flows in the Victoria Land coastal ocean region of the Western Ross Sea. Here we use oceanographic data from near to the tongue to explore the interplay between the floating glacier and the local currents and stratification. A vessel-based circuit of the glacier, recording ocean temperature and salinity profiles, reveals the southwest corner to be the coldest and most complex in terms of vertical structure. The southwest corner structure beneath the surface warm, salty layer sustains a block of very cold water extending to 200 m depth. In this same location there was a distinct layer at 370 m not seen anywhere else of water at ~−1.93°C. The new observations broadly, but not directly, support the presence of a coherent Victoria Land Coastal Current. The data suggest the northward moving coastal current turns against the Coriolis force and works its way anticlockwise around the glacier, but with leakage beneath the glacier through the highly ‘rippled’ underside, resulting in a spatially heterogeneous supply to the Terra Nova Bay Polynya region – an important location for the formation of high-salinity shelf water.

Two unpublished accounts of the British Antarctic Expedition, 1839–43

Polar Record ◽  
1961 ◽  
Vol 10 (69) ◽  
pp. 587-604
Keyword(s):  
Ross Sea ◽  
Terrestrial Magnetism ◽  
The North ◽  
Prince Edward Islands ◽  
Victoria Land ◽  
Antarctic Expedition ◽  
North Magnetic Pole ◽  
Antarctic Continent ◽  
James Ross Island ◽  
Set Up

[The British Antarctic Expedition, 1839–43, consisted of two Naval vessels, H.M.S. Erebus and Terror, with Sir James Clark Ross as leader and Captain F. R. M. Crozier as second-in-command. The objects of the expedition were mainly concerned with terrestrial magnetism, a subject of particular interest to Ross who had discovered the North Magnetic Pole in 1831. The expedition circumnavigated the Antarctic continent and made a number of important geographical discoveries. It twice penetrated the pack ice.of the Ross Sea; it discovered, and roughly charted, 500 miles of new coastline in Victoria Land; it discovered Ross Island and the Ross Ice Front, also the James Ross Island group; it visited Prince Edward Islands, les Crozet and les Kerguelen; and it sighted Joinville Island and the Balleny Islands. Observations of terrestrial magnetism were made from stations, either permanent or temporary, set up during the voyage.

scholarly journals Victoria Lower Glacier and Ross Sea Glaciation, Dry Valleys Area, South Victoria Land, Antarctica

1987 ◽  
Vol 33 (115) ◽  
pp. 293-299 ◽  
Author(s):  
T.J.H. Chinn
Keyword(s):  
Shear Zone ◽  
Ross Sea ◽  
Complex Structure ◽  
Radiocarbon Date ◽  
Dry Valleys ◽  
Radiocarbon Age ◽  
The North ◽  
Victoria Land ◽  
Radio Echo Sounding ◽  
Echo Sounding

AbstractVictoria Lower Glacier is a complex structure of ice from two distinct sources (Schultz Glacier to the north and a localnévéof Victoria Lower Glacier) that join at a broad median shear zone. Evidence from the margins suggest that both are currently retreating. Algae in a block of frozen stratified sediment from within the ice of the terminal margin has a radiocarbon age of 20 200 ± 2400 year BP (NZ 6531 A), indicating that the glacier has advanced since that time. Superposition of ice levels of Ross Sea I glaciation on a radio echo–sounding profile of bedrock beneath the glacier indicates that it is unlikely that Ross Sea I ice entered the valley. The radiocarbon date supports this finding.

Recent progress in magnetic anomaly mapping over Victoria Land (Antarctica) and the GITARA 5 survey

1999 ◽  
Vol 11 (2) ◽  
pp. 209-216 ◽  
Author(s):  
E. Bozzo ◽  
F. Ferraccioli ◽  
M. Gambetta ◽  
G. Caneva ◽  
M. Spano ◽  
...  
Keyword(s):  
Magnetic Anomaly ◽  
Crustal Structure ◽  
Ross Sea ◽  
Rift System ◽  
West Antarctic ◽  
The Pacific ◽  
Victoria Land ◽  
Line Spacing ◽  
Major Fault ◽  
Anomaly Map

Magnetic anomaly mapping is used to interpret crustal structure and tectonic evolution of Victoria Land and of the adjacent Ross Sea. Previous interpretation of magnetic anomalies verified seismic and gravimetric findings in the Ross Sea by placing additional constraints both on crustal structure and magmatism of the West Antarctic rift system. An aeromagnetic map of the central-southern part of Victoria Land produced in the framework of the GITARA project, provides new crustal images of part of the Transantarctic Mountains rift shoulder. The map was interpreted to study the transition between the Wilson Terrane and the Precambrian East Antarctic Craton, the extent and distribution of Jurassic tholeiitic magmatism, and the occurrence of post- Jurassic faulting oblique to the rift basins. A compilation with adjacent aeromagnetic data was recently used to study the structures inherited from the Palaeozoic terranes and their reactivation as major fault zones separating different crustal blocks along the TAM rift shoulder. Additional aeromagnetic coverage over a 35 500 km2 sector of northern Victoria Land was acquired during the GITARA 5 (1996/97) survey. The flight altitude was 9000 ft and profile line spacing was 4.4 km for the regional grid and 2.2 km for the detailed one, with a tie line interval of 22 km. Standard processing techniques, optimized with microlevelling procedures were applied to the data to produce a 1:250 000 magnetic anomaly map. The processed GITARA 5 magnetic dataset is a new tool to study the structure of the Rennick Graben, and its relationship to the Palaeozoic Wilson Terrane-Bowers Terrane and Robertson Bay Terrane suture zone. The new map also represents important progress towards a magnetic anomaly compilation over the whole of Victoria Land, since it links previous efforts near the Pacific Coast with those near the Ross Sea.

scholarly journals Victoria Lower Glacier and Ross Sea Glaciation, Dry Valleys Area, South Victoria Land, Antarctica

1987 ◽  
Vol 33 (115) ◽  
pp. 293-299
Author(s):  
T.J.H. Chinn
Keyword(s):  
Shear Zone ◽  
Ross Sea ◽  
Complex Structure ◽  
Radiocarbon Date ◽  
Dry Valleys ◽  
Radiocarbon Age ◽  
The North ◽  
Victoria Land ◽  
Radio Echo Sounding ◽  
Echo Sounding

AbstractVictoria Lower Glacier is a complex structure of ice from two distinct sources (Schultz Glacier to the north and a local névé of Victoria Lower Glacier) that join at a broad median shear zone. Evidence from the margins suggest that both are currently retreating. Algae in a block of frozen stratified sediment from within the ice of the terminal margin has a radiocarbon age of 20 200 ± 2400 year BP (NZ 6531 A), indicating that the glacier has advanced since that time. Superposition of ice levels of Ross Sea I glaciation on a radio echo–sounding profile of bedrock beneath the glacier indicates that it is unlikely that Ross Sea I ice entered the valley. The radiocarbon date supports this finding.

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