scholarly journals Sediment distribution and sedimentary processes across the Antarctic Wilkes Land margin during the Quaternary

2003 ◽  
Vol 50 (8-9) ◽  
pp. 1481-1508 ◽  
Author(s):  
C Escutia ◽  
D Warnke ◽  
G.D Acton ◽  
A Barcena ◽  
L Burckle ◽  
...  
Keyword(s):  
Sedimentary Processes ◽  
Sediment Distribution ◽  
Wilkes Land ◽  
The Antarctic

Identification and assessment of contaminated sites at Casey Station, Wilkes Land, Antarctica

Polar Record ◽  
1999 ◽  
Vol 35 (195) ◽  
pp. 299-316 ◽  
Author(s):  
Patrick P. Deprez ◽  
Michael Arens ◽  
Helen Locher
Keyword(s):  
Contaminated Soils ◽  
Relevant Literature ◽  
Contaminated Sites ◽  
Disposal Site ◽  
Lead And Zinc ◽  
Wilkes Land ◽  
The Antarctic ◽  
Antarctic Environment ◽  
Casey Station ◽  
Copper Lead

AbstractIn December 1993 a study of contaminated sites at Casey Station, Wilkes Land, Antarctica, was undertaken. The preliminary assessment of these contaminated sites is presented here. A register of contaminated sites for Casey Station was developed, based on a survey of past Antarctic expeditioners, relevant literature, and in-house reports relating to site usage and history. On this basis a sampling strategy was devised for the highest priority, potentially contaminated sites at Casey Station. Samples were collected from the refuse disposal site (tip site) at Thala Valley and the mechanical workshop/powerhouse areas of ‘Old’ Casey. The results indicated that copper, lead, and zinc were leaching from the tip site into adjacent Brown Bay, with ‘hot spots’ of high petroleum hydrocarbon levels. The mechanical workshop/powerhouse area was also shown to be contaminated with petroleum hydrocarbons, polycyclic aromatic hydrocarbons, and metals such as copper, lead, and zinc. Several recommendations were made, including the removal of rubbish mixed with soil at the bottom end of Thala Valley in such a manner as to prevent any further release of contaminants, with subsequent site monitoring to verify effective removal of contaminants to acceptable environmental levels. It was also recommended that further investigations be carried out on the ecosystem of Brown Bay, the large fuel spill site, the upper and lower fuel-storage areas, and the area around the incinerator. There is scope for monitoring the natural breakdown and migration of contaminants at the mechanical workshop/powerhouse site. This should include studies on bioremediation of hydrocarbon-contaminated soils. Mechanisms for arresting surface migration should be investigated in those sites identified. In addition to meeting some of the international obligations of the Protocol on Environmental Protection to the Antarctic Treaty, this work also contributes towards the development of an approach to assessment and management of contaminated sites that is uniquely adapted to the Antarctic environment and could be applied at other Antarctic stations. to the assessment and management of contaminated sites that is uniquely adapted to the Antarctic environment. This approach could be utilised for site assessments at other Antarctic stations.

scholarly journals A 14-yr Circum-Antarctic Iceberg Calving Dataset Derived from Continuous Satellite Observations

2021 ◽  
Author(s):  
Mengzhen Qi ◽  
Yan Liu ◽  
Jiping Liu ◽  
Xiao Cheng ◽  
Qiyang Feng ◽  
...  
Keyword(s):  
Mass Loss ◽  
Ice Sheets ◽  
Data Repository ◽  
Main Process ◽  
Ice Shelves ◽  
Radar Images ◽  
Wilkes Land ◽  
Iceberg Calving ◽  
Interval Type ◽  
The Antarctic

Abstract. Iceberg calving is the main process that facilitates the dynamic mass loss of ice sheets into the ocean, which accounts for approximately half of the net mass loss of all Antarctic ice shelves. Fine-scale calving variability observations can help reveal the involved calving mechanisms and identify the principal processes that influence how the changing climate affects the mass loss of ice sheets. Iceberg calving from specific ice shelves or regions has been monitored before, but there is still a lack of consistent, long-term and high-precision records on independent calving events for all Antarctic ice shelves. In this study, we developed a circum-Antarctic annual iceberg calving product measuring every independent calving event larger than 1 km2 that occurred from August 2005 to August 2019. We first simulated the expansion of the coastline according to ice velocity, and then manually delineated the calved areas, which are considered to be the differences between the simulated coastline and the actual coastline derived from the corresponding satellite imagery, based on 15 years of continuous multisource optical and synthetic aperture radar images. This product provides detailed information on each calving event, including the associated year of occurrence, area, size, average thickness, mass, recurrence interval, type, and measurement uncertainties. In total, 1786 annual calving events occurred on the Antarctic ice shelves from August 2005 to August 2019. The average annual calving area was measured as 3411.4 km2 with an uncertainty value of 17.1 km2, and the average calving rate was measured as 771.1 Gt/yr with an uncertainty value of 10.2 Gt/yr. The calving frequency, area, and mass fluctuated moderately during the first decade, followed by a dramatic increase from 2015/16 to 2018/19. During the dataset period, large ice shelves, such as the Ronne-Filchner, Ross and Amery Ice Shelves, advanced with low calving frequency, while small and medium-sized ice shelves retreated and calved more frequently. Iceberg calving is most prevalent in West Antarctica, followed by the Antarctic Peninsula and Wilkes Land in East Antarctica. The annual circum-Antarctic iceberg calving dataset provides consistent and precise calving observations with the longest time coverage. The dataset provides multidimensional variables for each independent calving event that can be used to study detailed spatiotemporal variations in Antarctic iceberg calving. The dataset can also be used to study ice sheet mass balance, calving mechanisms and the responses of iceberg calving to climate change. The dataset is shared via Global Change Data Repository (href="http://www.geodoi.ac.cn/WebEn/doi.aspx?Id=1516), and entitled Annual iceberg calving dataset of the Antarctic ice shelves (2005–2019) with DOI: https://doi.org/10.3974/geodb.2020.04.09.V1.

scholarly journals Oligocene TEX<sub>86</sub>-derived seawater temperatures from offshore Wilkes Land (East Antarctica)

2017 ◽  
Author(s):  
Julian D. Hartman ◽  
Francesca Sangiorgi ◽  
Ariadna Salabarnada ◽  
Francien Peterse ◽  
Alexander J. P. Houben ◽  
...  
Keyword(s):  
Sea Ice ◽  
Bottom Water ◽  
Ice Sheet ◽  
Temperature Variability ◽  
Sea Surface ◽  
Ice Volume ◽  
Sst Variability ◽  
Wilkes Land ◽  
The Antarctic

Abstract. Today, the temperature of the surface waters near the Antarctic coast is a determining factor in the formation of Antarctic Bottom Water (AABW) through sea-ice production, sea-ice extent, and the extent of the ice shelf. For the Oligocene, deep-sea benthic foraminiferal oxygen isotope (δ18O) reconstructions suggest that the volume of the Antarctic continental ice sheet(s) varied substantially both on million-year and on orbital timescales after its inception in the early Oligocene, and even reached larger than modern-day volumes. Replication of such dynamicity through physical modeling remains problematic, suggesting the existence of complex feedbacks between the cryosphere, the ocean and the atmosphere. To assess the relation between cryosphere, ocean and atmosphere, knowledge of sea surface conditions close to the Antarctic margin is essential. We present a TEX86-based surface water paleotemperature record measured on Oligocene sediments from Integrated Ocean Drilling Program (IODP) Site U1356, offshore Wilkes Land, Antarctica. This record allows us to reconstruct the magnitude of seawater temperature variability and trends on both million-year and on glacial-interglacial timescales. TEX86 index values suggest surface temperatures between 10 and 21 °C during the Oligocene, which is on the upper end of the few available reconstructions. Sea surface temperature (SST) maxima occur around 30.5 and 25 Ma, irrespective of the calibration equation chosen. Based on glacial-interglacial lithological alternations we have established that SST variability between glacial intervals and their successive interglacials ranged between 1.8–3.2 °C. As benthic foraminiferal δ18O data incorporate both an ice-volume and a temperature component, our reconstructed Oligocene temperature variability could have implications for current Oligocene ice-volume estimates. If the long-term ad orbital SST variability is representative of that of the nearby region of deep-water formation, we can assess the impact of this temperature record on the volume and dynamics of the Antarctic ice sheet(s) by comparing it with the δ18O trends and variability. From this comparison, we argue that a significant portion of the variability and trends contained in long-term δ18O records can be explained by variability in Southern high-latitude temperature. If indeed a large part of the δ18O variability is due to large glacial-interglacial bottom-water temperature shifts, the Oligocene Antarctic ice volume was less sensitive to climate change than previously assumed.

scholarly journals Two decades of Antarctic coastal-change revealed by satellite imagery and deep learning

2021 ◽  
Author(s):  
Celia A. Baumhoer ◽  
Andreas Dietz ◽  
Mariel Dirscherl ◽  
Claudia Kuenzer
Keyword(s):  
Deep Learning ◽  
Ice Sheet ◽  
Continuous Mapping ◽  
Coastal Change ◽  
Ice Shelf ◽  
Antarctic Ice Sheet ◽  
Ice Shelves ◽  
Ross Ice Shelf ◽  
Wilkes Land ◽  
The Antarctic

&lt;p&gt;Antarctica&amp;#8217;s coastline is constantly changing by moving glacier and ice shelf fronts. The extent of glaciers and ice shelves influences the ice discharge and sea level contribution of the Antarctic Ice Sheet. Therefore, it is crucial to assess where ice shelf areas with strong buttressing forces are lost. So far, those changes have not been assessed for entire Antarctica within comparable time frames.&lt;/p&gt;&lt;p&gt;We present a framework for circum-Antarctic coastline extraction based on a U-Net architecture. Antarctic coastal-change is calculated by using a deep learning derived coastline for the year 2018 in combination with earlier manual derived coastlines of 1997 and 2009. For the first time, this allows to compare circum-Antarctic changes in glacier and ice shelf front position for the last two decades. We found that the Antarctic Ice Sheet area decreased by -29,618&amp;#177;1,193 km&lt;sup&gt;2&lt;/sup&gt; in extent between 1997-2008 and gained an area of 7,108&amp;#177;1,029km&lt;sup&gt;2&lt;/sup&gt; between 2009 and 2018. Retreat dominated for the Antarctic Peninsula and West Antarctica and advance for the East Antarctic Ice Sheet over the entire investigation period. The only exception in East Antarctica was Wilkes Land experiencing simultaneous calving front retreat of several glaciers between 2009-2018. Biggest tabular iceberg calving events occurred at Ronne and Ross Ice Shelf within their natural calving cycle between 1997-2008. Future work includes the continuous mapping of Antarctica&amp;#8217;s coastal-change on a more frequent temporal scale. &amp;#160;&lt;/p&gt;

Sedimentary processes on the Wilkes Land continental rise reflect changes in glacial dynamic and bottom water flow

2009 ◽  
Vol 99 (4) ◽  
pp. 909-926 ◽  
Author(s):  
Andrea Caburlotto ◽  
R. G. Lucchi ◽  
L. De Santis ◽  
P. Macrì ◽  
R. Tolotti
Keyword(s):  
Water Flow ◽  
Bottom Water ◽  
Sedimentary Processes ◽  
Continental Rise ◽  
Wilkes Land

Satellite magnetic anomalies of the Antarctic Wilkes Land impact basin inferred from regional gravity and terrain data

2013 ◽  
Vol 585 ◽  
pp. 185-195 ◽  
Author(s):  
R.R.B. von Frese ◽  
H.R. Kim ◽  
T.E. Leftwich ◽  
J.W. Kim ◽  
A.V. Golynsky
Keyword(s):  
Magnetic Anomalies ◽  
Wilkes Land ◽  
Regional Gravity ◽  
The Antarctic
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