Sub-Ice Topography in Selected Areas of Victoria Land, Antarctica: Implications for Its Glacial Erosion History

Author(s):  
G. Delisle
1974 ◽  
Vol 13 (69) ◽  
pp. 415-429
Author(s):  
Parker E. Calkin

The results of airborne radio-echo (R/E) depth sounding over Wilson Piedmont Glacier, Mackay, Ferrar and Taylor outlet glaciers, and over the ice sheet bordering the mountains, provide ice thicknesses and subglacial topography accurate to 20 m and to 1 km areally. The R/E records show that flours of the Debenham, Wright and Victoria Valleys occur beneath the Wilson Piedmont at elevations of –260 m, and up to 260 and 670 m, respectively. The 670 m “threshold” may have blocked easterly marine and glacial invasions experienced by lower valleys. Profiles along the outlet glaciers display large depressions, some below sea-level. These are associated with erosion by tributaries and with glacial erosion through thick dolerite sills. Elevated ridges thought to be sills submerged beneath the heads of these glaciers also limit nourishment from the adjacent part of the ice sheet. The subglacial west flank of the mountains is formed by a series of high steep-sided plateaux with gentle west-sloping surfaces. Block faulting, west-dipping dolerite and sandstone units, and glacial erosion must explain this topography.


1974 ◽  
Vol 13 (69) ◽  
pp. 415-429 ◽  
Author(s):  
Parker E. Calkin

The results of airborne radio-echo (R/E) depth sounding over Wilson Piedmont Glacier, Mackay, Ferrar and Taylor outlet glaciers, and over the ice sheet bordering the mountains, provide ice thicknesses and subglacial topography accurate to 20 m and to 1 km areally. The R/E records show that flours of the Debenham, Wright and Victoria Valleys occur beneath the Wilson Piedmont at elevations of –260 m, and up to 260 and 670 m, respectively. The 670 m “threshold” may have blocked easterly marine and glacial invasions experienced by lower valleys. Profiles along the outlet glaciers display large depressions, some below sea-level. These are associated with erosion by tributaries and with glacial erosion through thick dolerite sills. Elevated ridges thought to be sills submerged beneath the heads of these glaciers also limit nourishment from the adjacent part of the ice sheet. The subglacial west flank of the mountains is formed by a series of high steep-sided plateaux with gentle west-sloping surfaces. Block faulting, west-dipping dolerite and sandstone units, and glacial erosion must explain this topography.


2020 ◽  
Vol 32 (5) ◽  
pp. 382-395
Author(s):  
Encelyn Voisine ◽  
Yann Rolland ◽  
Matthias Bernet ◽  
Julien Carcaillet ◽  
Guillaume Duclaux ◽  
...  

AbstractWe report apatite fission-track and 10Be terrestrial cosmogenic nuclide (TCN) dating of 14 moraine boulders originating from inland Terre Adélie, East Antarctica. These data show cooling of the Proterozoic Terre Adélie craton at < ~120°C between 350 and 300 Ma, suggesting > 4 km temperate glacial erosion during the Late Palaeozoic Ice Age, followed by nearly null Mesozoic erosion and low glacial erosion (< 2 km) in the Cenozoic. Based on glacial flux maps, the origin of the boulders may be located ~400 km upstream. Preliminary TCN (10Be) datings of moraine boulders cluster within the last 30 ka. Cosmogenic ages from the Lacroix Nunatak suggest a main deglaciation after the Younger Dryas at c. 10 ka, while those of Cap Prud'homme mostly cluster at 0.6 ka, in agreement with an exhumation of boulders during the Little Ice Age.


2020 ◽  
Author(s):  
Bailey Nordin ◽  
◽  
Stephen E. Cox ◽  
Sidney Hemming ◽  
Stuart N. Thomson ◽  
...  

Taxonomy ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 116-141
Author(s):  
Claudia Brunetti ◽  
Henk Siepel ◽  
Pietro Paolo Fanciulli ◽  
Francesco Nardi ◽  
Peter Convey ◽  
...  

Two new mite species belonging to the genus Stereotydeus Berlese, 1901 were discovered from locations along the coast of Victoria Land, continental Antarctica. Previous records of this genus in the area under study only reported the presence of S. belli and S. mollis. Although those studies included no morphological analyses, it has since been assumed that only these species were present within the area. Specimens of S. ineffabilis sp. nov. and S. nunatakis sp. nov. were obtained, sometimes in sympatry, from four different localities in Central and South Victoria Land and are here described and illustrated using optical and scanning electron microscopy (SEM) techniques. Features useful for identification of the two new Stereotydeus species include the size of the specimens, the length of the apical segment of pedipalps, the presence/absence of division of the femora, the position of solenidia, the shape and disposition of the rhagidiform organs on the tarsi, the shape of the apical setae of the tarsi, the numbers of aggenital setae and the position of the anal opening. A key to 14 of the 15 currently described Antarctic and sub-Antarctic Stereotydeus species is provided.


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