“…Most recently, BEDMAP2 datasets and maps (Fretwell et al 2013) and examination of the origin and subglacial topography of the WSB (Weihaupt et al 2014a) have again confirmed the validity of using gravity data to profile the subglacial topography in East Antarctica. Fig. 1 Route of the United States Victoria Land Traverse (VLT) of 1959–60 (after Weihaupt 1961; base map compliments SCAR). Station 531 marks the westernmost point of the VLT where it joins the French Adélie Land Traverse of 1958–59 (Rouillon 1960).…”
Section: Introductionmentioning
confidence: 89%
“…6a Enlargement of the area of the subglacial topography of the Wilkes Land Anomaly (WLA) shown in Figs 4 & 5. Compiled from Victoria Land Traverse and Adélie Land Traverse ground-based gravity and seismic surveys (after Rouillon 1960, Weihaupt 1961, Weihaupt et al 2010, Weihaupt et al 2012), from airborne radiosound survey (after Steed & Drewry 1982), from airborne gravity and magnetic survey (after Ferraccioli et al 2001) and from the BEDMAP2 dataset (after Fretwell et al 2013). b. Mosaic of RADARSAT imaging of the continental ice sheet surface overlying the WLA, reflecting the subglacial morphology of the craterform structure.…”
Section: Gravity Deficitmentioning
confidence: 99%
“…Sloping toward the continental coastline to the north, the ice sheet is underlain by subglacial rock topography of relatively moderate relief that varies from 1700–2300 m above sea level, and displays regional free air gravity anomalies that range from -42.6 to +23.7 mgal, averaging a rate of change of 0.1 mgal km -1 over a distance of c . 700 km (Weihaupt 1961). In contrast, the area of the WLA is characterized by steeper ice surface slopes to the coast of the Southern Ocean, and consequently more rapid movement of the continental ice sheet.…”
Section: Geological and Geophysical Settingmentioning
confidence: 99%
“…The VLT also discovered the Wilkes Land Anomaly (WLA), a substantial gravity anomaly centred at 70°00'S-140°00'E. The feature exhibited a negative free air gravity anomaly of 158.3 mgals (Weihaupt 1961, 1976, Schmidt 1962) that has been a subject of interest and some controversy (Bentley 1979) since first reported. The controversy, a dispute about the use of gravity data over the 400 km transect of the WLA to define subglacial topography, was resolved by examination of the gravity profile of the remaining 2000 km of the same survey.…”
Section: Introductionmentioning
confidence: 99%
“…Route of the United States Victoria Land Traverse (VLT) of 1959–60 (after Weihaupt 1961; base map compliments SCAR). Station 531 marks the westernmost point of the VLT where it joins the French Adélie Land Traverse of 1958–59 (Rouillon 1960).…”
International audienceThe Wilkes Land Gravity Anomaly, first reported in 1959–60, is located in northern Victoria Land in the Pacific Ocean sector of East Antarctica, 1400 km west of the Ross Sea and centred at 70°00'S-140°00'E. Initially described on the basis of ground-based seismic and gravity survey, and estimated at the time to have a diameter of 243 km, the original data are now supplemented by data from airborne radiosound survey, airborne gravity survey, airborne magnetic survey and satellite remote sensing. These new data enable us to expand upon the original data, and reveal that the structure has a diameter of some 510 km, is accompanied by ice streams and a chaotically disturbed region of the continental ice sheet, has a subglacial topographical relief of ≥1500 m, and exhibits a negative free air gravity anomaly associated with a larger central positive free air gravity anomaly. The feature has been described as a volcanic structure, an igneous intrusion, an ancient igneous diapir, a subglacial sedimentary basin, a glacially eroded subglacial valley, a tectonic feature and a meteorite impact crater. We re-examine the feature on the basis of these collective data, with emphasis on the free air gravity anomaly signs, magnitudes and patterns, magnetic signature magnitudes and patterns, and the size, shape, dimensions and morphology of the structure. This enhanced view adds substantially to the original description provided at the time of discovery, and suggests several explanations for the origin of the Wilkes Land Anomaly. However, the importance of this feature lies not only in determining its origin but by the fact that this part of the Wilkes Subglacial Basin is one of the most prominent regional negative geoid and associated gravity anomalies of the Antarctic continent
“…Most recently, BEDMAP2 datasets and maps (Fretwell et al 2013) and examination of the origin and subglacial topography of the WSB (Weihaupt et al 2014a) have again confirmed the validity of using gravity data to profile the subglacial topography in East Antarctica. Fig. 1 Route of the United States Victoria Land Traverse (VLT) of 1959–60 (after Weihaupt 1961; base map compliments SCAR). Station 531 marks the westernmost point of the VLT where it joins the French Adélie Land Traverse of 1958–59 (Rouillon 1960).…”
Section: Introductionmentioning
confidence: 89%
“…6a Enlargement of the area of the subglacial topography of the Wilkes Land Anomaly (WLA) shown in Figs 4 & 5. Compiled from Victoria Land Traverse and Adélie Land Traverse ground-based gravity and seismic surveys (after Rouillon 1960, Weihaupt 1961, Weihaupt et al 2010, Weihaupt et al 2012), from airborne radiosound survey (after Steed & Drewry 1982), from airborne gravity and magnetic survey (after Ferraccioli et al 2001) and from the BEDMAP2 dataset (after Fretwell et al 2013). b. Mosaic of RADARSAT imaging of the continental ice sheet surface overlying the WLA, reflecting the subglacial morphology of the craterform structure.…”
Section: Gravity Deficitmentioning
confidence: 99%
“…Sloping toward the continental coastline to the north, the ice sheet is underlain by subglacial rock topography of relatively moderate relief that varies from 1700–2300 m above sea level, and displays regional free air gravity anomalies that range from -42.6 to +23.7 mgal, averaging a rate of change of 0.1 mgal km -1 over a distance of c . 700 km (Weihaupt 1961). In contrast, the area of the WLA is characterized by steeper ice surface slopes to the coast of the Southern Ocean, and consequently more rapid movement of the continental ice sheet.…”
Section: Geological and Geophysical Settingmentioning
confidence: 99%
“…The VLT also discovered the Wilkes Land Anomaly (WLA), a substantial gravity anomaly centred at 70°00'S-140°00'E. The feature exhibited a negative free air gravity anomaly of 158.3 mgals (Weihaupt 1961, 1976, Schmidt 1962) that has been a subject of interest and some controversy (Bentley 1979) since first reported. The controversy, a dispute about the use of gravity data over the 400 km transect of the WLA to define subglacial topography, was resolved by examination of the gravity profile of the remaining 2000 km of the same survey.…”
Section: Introductionmentioning
confidence: 99%
“…Route of the United States Victoria Land Traverse (VLT) of 1959–60 (after Weihaupt 1961; base map compliments SCAR). Station 531 marks the westernmost point of the VLT where it joins the French Adélie Land Traverse of 1958–59 (Rouillon 1960).…”
International audienceThe Wilkes Land Gravity Anomaly, first reported in 1959–60, is located in northern Victoria Land in the Pacific Ocean sector of East Antarctica, 1400 km west of the Ross Sea and centred at 70°00'S-140°00'E. Initially described on the basis of ground-based seismic and gravity survey, and estimated at the time to have a diameter of 243 km, the original data are now supplemented by data from airborne radiosound survey, airborne gravity survey, airborne magnetic survey and satellite remote sensing. These new data enable us to expand upon the original data, and reveal that the structure has a diameter of some 510 km, is accompanied by ice streams and a chaotically disturbed region of the continental ice sheet, has a subglacial topographical relief of ≥1500 m, and exhibits a negative free air gravity anomaly associated with a larger central positive free air gravity anomaly. The feature has been described as a volcanic structure, an igneous intrusion, an ancient igneous diapir, a subglacial sedimentary basin, a glacially eroded subglacial valley, a tectonic feature and a meteorite impact crater. We re-examine the feature on the basis of these collective data, with emphasis on the free air gravity anomaly signs, magnitudes and patterns, magnetic signature magnitudes and patterns, and the size, shape, dimensions and morphology of the structure. This enhanced view adds substantially to the original description provided at the time of discovery, and suggests several explanations for the origin of the Wilkes Land Anomaly. However, the importance of this feature lies not only in determining its origin but by the fact that this part of the Wilkes Subglacial Basin is one of the most prominent regional negative geoid and associated gravity anomalies of the Antarctic continent
Abstract:The Wilkes Subglacial Basin (WSB), the largest subglacial basin in East Antarctica, is a topographic depression of continental proportions that lies beneath the East Antarctic continental ice sheet. Discovered by the US Victoria Land Traverse 1959-60, the origin of the WSB and the influence of palaeoclimate on its overlying continental ice sheet have remained uncertain since the time of its discovery. Most explanations of origin favour lithospheric structural control as a function of tectonic activity. Lithospheric flexure due to thermally or isostatically induced uplift of the Transantarctic Mountains was suggested in the 1980s. Lithospheric extension and rifting was proposed in the 1990s. More recent investigations have revealed the presence of fold and thrust belts, casting doubt on flexural and extensional hypotheses as the primary mechanisms, suggesting instead a compressional scenario. While remaining inconclusive, these tectonic mechanisms in one form or another, or in combination, are now believed to have provided the structural control for the origin of the WSB. Not yet comprehensively examined, however, is the role of non-tectonic processes in the formation of the WSB, as they may have influenced the size, configuration, subglacial sedimentation and subglacial topography of the WSB. In this paper we review the tectonic hypotheses and examine post-tectonic climate change along with glacial and marine processes as potentially significant factors in the present condition and configuration of the WSB. In the process, we find that there are a number of features not included in previous investigations that may have been major factors in the modification of the subglacial basin.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
