Seismic stratigraphic evidence of ice-sheet advances on the Wilkes Land margin of Antarctica

Late Oligocene obliquity-paced contourite sedimentation in the Wilkes Land margin of East Antarctica: implications for paleoceanographic and ice sheet configurations

“…440 The depositional setting on the continental rise was however different during the late Oligocene. The stratigraphic evolution of the region testifies the progradation of the continental shelf taking place after continental ice sheet build-up during the Eocene-Oligocene Transition (EOT, 34 Ma) (Eittreim et al, 1995;Escutia et al, 1997;Escutia et al, 2005), which resulted in: 1) seismic and sedimentary facies becoming more proximal up-section (Hayes and Frakes, 1975;Escutia et el., 2000;Escutia et al, 2005;445 Escutia et al, 2014), and 2) high sedimentation rates during the Oligocene (Escutia et al, 2011;Tauxe et al, 2012). In this context, the late Oligocene sediments from Site U1356 record distal continental rise deposition in an incipient/low-relief levee of a channel-levee complex.…”

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

“…A prominent regional unconformity (WL-U3) within the Cenozoic post-rift section beneath the continental shelf ( Fig. WL-2) is believed to be due to erosional processes related to the first advance of grounded ice sheets onto the continental shelf (Eittreim and Smith, 1987;Tanahashi et al, 1994;Eittreim et al, 1995;Escutia et al, 1997;Escutia et al, 2005). The pre-ice-sheet strata below unconformity WL-U3, where resolvable, are flat-lying and less stratified than glacial strata above the unconformity.…”

“…The sequences are deeply eroded by broad troughs that cross the shelf. The troughs are interpreted as the erosional paths of ice streams during times of glacial maxima (Eittreim et al, 1995). Foreset strata are commonly truncated at or near the seafloor beneath the troughs ( Fig.…”

“…Ice is inferred to have moved slowly over bank areas and rapidly in the troughs. Geometry of strata in buried troughs on the shelf suggests to some (Eittreim et al, 1995;Escutia et al, 2000) that the locations of ice streams and their erosional troughs and banks have shifted during consecutive glacial advances. Regional glacial seismic sequences and unconformities defined by different workers (Table WL- 1) in the EWL were renamed and in some cases redefined by De .…”

“…regional unconformities, WL-U3 and WL-U8 (Wannesson et al, 1985;Eittreim and Smith, 1987;Hampton et al, 1987;De Santis et al, 2003), and the erosion is thought to result from grounded ice sheets moving across the continental shelf (Tanahashi et al, 1994;Eittreim et al, 1995;Escutia et al, 1997;Escutia et al, 2005). Eittreim et al (1995) calculated erosion of 300 to 600 m of strata below WL-U3.…”