Distribution of glacial geomorphic features on the Antarctic continental shelf and correlation with substrate: implications for ice behavior

Abstract

Surveys were conducted seaward of all the major drainage outlets of the Antarctic ice sheet from the Pennell Coast, northVictoria Land, to Marguerite Bay, Antarctic Peninsula. The results show that the ice sheet extended onto the outer shelf. Glacial troughs occur offshore of all major glacial outlets.Where the substrate is crystalline bedrock, ice flow tended to follow the structural grain of the bedrock, deposited little sediment and eroded the underlying bedrock. Where ice flowed over relatively soft, more easily eroded, sedimentary strata, the direction of ice flow was more directly offshore, and depositional features characterize the sea-floor. In these areas the signature of the grounded ice consists of till deposits and large-scale geomorphic features. Drumlins occur within the region of contact between crystalline and sedimentary substrates. The different geological substrates are interpreted to have exerted a fundamental control on the behavior of past ice sheets. The troughs in the areas of bedrock composed of sedimentary substrate are interpreted to have been occupied by relatively fast-flowing ice, ice streams, and the troughs in the areas of crystalline substrate are interpreted to have been occupied by slower-moving ice. The area between these two zones was characterized by ice acceleration and is marked by drumlins.

The sedimentary legacy of a palaeo-ice stream on the shelf of the southern Bellingshausen Sea: Clues to West Antarctic glacial history during the Late Quaternary

“…Our interpretations are largely consistent with published facies classifications from elsewhere on the Antarctic shelf (e.g. Kurtz and Anderson, 1979;Anderson et al, 1980;Wright and Anderson, 1982;Licht et al, 1996Licht et al, , 1998Licht et al, , 1999Domack et al, 1998Domack et al, , 1999Domack et al, , 2005Anderson, 1999;Pudsey and Evans, 2001;Wellner et al, 2001;Evans and Pudsey, 2002; We interpret muddy diamictons of the lower lithological unit, which are characterised by medium to high shear strength values, low CaCO 3 contents and only minor fluctuations in MS, water content, WBD and grain-size composition, as subglacial soft tills (ST) deposited at the base of the ice stream that had advanced through Belgica Trough (Table 2, Fig. 2).…”

“…Multi-beam swath bathymetry data published by Wellner et al (2001Wellner et al ( , 2006 revealed that the seafloor on the shelf north of Eltanin Bay exhibits a wide range of subglacial bedforms including largescale P-forms eroded into bedrock on the inner shelf evolving into elongated drumlins and mega-scale glacial lineations (MSGL) on the middle shelf. Wellner et al (2001) argued that the bathymetric data point to the presence of a large cross-shelf trough and that sediment cores collected from the MSGLs recovered soft tills.…”

“…Wellner et al (2001) argued that the bathymetric data point to the presence of a large cross-shelf trough and that sediment cores collected from the MSGLs recovered soft tills. Wellner et al (2001Wellner et al ( , 2006 inferred from these observations that the WAIS had expanded onto the southern Bellingshausen Sea shelf at the LGM.…”

“…Shipp et al, 1999;Wellner et al, 2001Wellner et al, , 2006Lowe and Anderson, 2002;Heroy and Anderson, 2005;Ó Cofaigh et al, 2005a,b;Walker et al, 2007;Larter et al, 2009). The ice stream flowing through Belgica Trough also probably differed from other West Antarctic ice streams, because it drained an area >200,000 km 2 in the hinterland (see Fig.…”

Chapter 5 Cenozoic Climate History from Seismic Reflection and Drilling Studies on the Antarctic Continental Margin

“…These regions include similar geomorphic and stratigraphic features. Although we do not include them in the discussion below due to space considerations, we include here representative citations to some of the studies published for the Bellingshausen and Amundsen seas Tucholke and Houtz, 1976;Tucholke, 1977;Kimura, 1982;Yamaguchi et al, 1988;Cunningham et al, 1994Cunningham et al, , 2002Gohl et al, 1997Gohl et al, , 2007Nitsche et al, 1997Nitsche et al, , 2000Wellner et al, 2001Wellner et al, , 2006Lowe and Anderson, 2002;Ó Cofaigh et al, 2005;Dowdeswell et al, 2006;Evans et al, 2006;Scheuer et al, 2006a, b;Larter et al, 2007;Uenzelmann-Neben et al, 2007) and for offshore areas of Queen Maud Land and Enderby Land (Kuvaas et al, 2004a(Kuvaas et al, , b, 2005Hinz et al, 2005;Stagg et al, 2004a, b;Leitchenkov et al, 2007;Solli et al, 2007a, b, c).…”