Cenozoic environmental changes along the East Antarctic continental margin inferred from regional seismic stratigraphy

Abstract

We interpret ~40 000 km of multichannel seismic reflection lines collected by the Russian Antarctic Expedition along the East Antarctic continental margin between 32 o E and 115 o E, and present a revised seismic stratigraphic model for depositional paleoenvironments of the region. Variations in acoustic facies characteristics observed across major seismic horizons are correlated with paleoenvironmental changes deciphered from Antarctic drilling data and deep-sea "proxy" records. Our results, as well as other studies, indicate that the East Antarctic margin was glaciated at different times. Glacial ice first reached the western Wilkes Land margin in the Middle Eocene and then advanced onto most parts of the East Antarctic continental shelf during the earliest Oligocene. During the Neogene, bottom currents deposited a variety of drift deposits along the margin.

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

“…Recent studies on the WWL margin glacial strata show a similar evolution of the glacial sedimentary sequences (i.e. increased proximal turbidite facies up-section and influence of bottomcontour-current deposition) above unconformities 'eoc' (Close et al, 2007) and WL3 (Leitchenkov et al, 2007), which correlate with WL-U3 on the EWL. Between 1101 and 1301 large debris-flow deposits are also reported forming throughout the Miocene (Donda et al, 2007a, b).…”

“…WL-1) formed during the Cretaceous separation of Australia and Antarctica (Cande and Mutter, 1982;Veevers, 1987;Sayers et al, 2001;Colwell et al, 2006;Leitchenkov et al, 2007;O'Brien and Stagg, 2007). The stratigraphy of the margin is known mainly from the seismic stratigraphic interpretation of numerous MCS surveys (Sato et al, 1984;Wanneson et al, 1985;Tsumuraya et al, 1985;Eittreim and Hampton, 1987;Ishihara et al, 1996;Tanahashi et al, 1997;Brancolini and Harris, 2000;Stagg et al, 2004a, b); complemented by surface sediment cores (Domack et al, 1980;Domack, 1982;Tsumuraya et al, 1985;Hampton et al, 1987;Ishihara et al, 1996;Tanahashi et al, 1997;Brancolini and Harris, 2000;Leventer et al, 2001;Escutia et al, 2003;Michel et al, 2006); and limited deep geological sampling recovery at DSDP Sites 268 and 269 .…”

“…The best-surveyed area is the eastern Wilkes Land margin (EWL) from the Ade´lie Coast to George V Land. West of this area (the western Wilkes Land margin-WWL), Japan and Russia collected widely spaced seismic lines that were then augmented during the 2001-2002 Australian Antarctic and Southern Ocean Profiling (ASSOPP) Project (Stagg et al, 2004a, b;Leitchenkov et al, 2007).…”

“…Pre-Eocene syn-rift strata are about 3 km thick and are highly variable in seismic character, with discontinuous, faulted, and tilted strata onlapping the flanks of the acoustic basement (Eittreim and Smith, 1987;Eittreim, 1994;De Santis et al, 2003;Stagg et al, 2004a, b;Leitchenkov et al, 2007).…”

“…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).…”