6.7 From: Fütterer DK, Damaske D, Kleinschmidt G, Miller H, Tessensohn F (eds) (2006) Antarctica: Contributions to global earth sciences. Springer-Verlag, Berlin Heidelberg New York, pp 341–348 Abstract. The Australian Antarctic and Southern Ocean Profiling Project has acquired more than 20 000 km of north-south seismic reflection transects every 90 km along the East Antarctic continen- tal margin between 38° E to 164° E. These data provide a unique overview of the broad scale depositional patterns around a large part of the Antarctic margin. Each line was examined and the post- rift section classified according to depositional environment. The depositional environments recognised are: 1. Submarine fans. 2. Contourite drift and canyon complexes. 3. Mixed contourite-turbidite drift sediments. 4. Thin separated drifts. 5. Non-deposition and erosion of older sediments. 6. Prograding upper slope wedges. 7. Distal abyssal plain deposits. We have recognised nine sedimentary provinces on the conti- nental slope and rise, based on the relative dominance of these environments. The distribution of contourite deposits is controlled by sediment input from the continent and by the shape of the mar- gin. Prydz Bay has provided a large amount of sediment over a long period, producing the thickest post-rift sediment pile on the mar- gin. It has been suggested that major sediment inputs have taken place via the Wilkes sub-glacial Basin, the Aurora Basin and Prydz Bay through the Lambert Graben. Our examination of the data im- plies that only Prydz Bay, western Enderby Land and the area at about Latitude 120° E have received large influxes of sediment, with western Enderby Land being relatively inactive during the Neogene. Sediment thicknesses are large when compared to the conjugate margin of Australia. Introduction The marine sedimentary environments around Ant- arctica are very poorly known because only a small proportion of the margin has been surveyed systemati- cally with reflection seismic data (ANTOSTRAT 2003). Effort has tended to concentrate in areas that are rela- tively easy to access or where initial surveys took place in the 1980s. In these areas, there is enough data to allow development of hypotheses for testing by new surveys and scientific drilling. Along the East Antarctic margin, surveys have concentrated in Prydz Bay and on the George V-Terra Adélie-Wilkes Land margin. Here we report on the results of three surveys that collected regularly-distributed seismic lines across the Antarctic margin, often in areas where there were little pre-exist- ing data. The wide distribution of the surveys and the high quality of the data provide an unparalled opportu- nity to examine sedimentary patterns along a large part of the Antarctic margin. Data Set The Australian Antarctic and Southern Ocean Profiling Project (AASOPP) collected geophysical data along the East Antarctic continental margin from 38° E to 164° E in three surveys in the Austral summers of 2000/2001 and 2001/2002 (Fig. 6.7-1). About 20 000 line-km comprised 36-fold deep-seismic data (60 l airgun array source; 3 600 m streamer; 288 channels; 16 s record length), col- lected with coincident gravity and magnetics data and refraction/wide-angle sonobuoys (Geoscience Australia Surveys GA-228 and GA-229, Fig. 6.7-1). A further 3 425 km of high-speed seismic data of limited penetra- tion (6 l airgun array, 300 m streamer, 24 channels, 8 s record length) were also recorded during Geoscience Australia Survey GA227. All data were stacked and mi- grated. The deep-seismic lines extend from the mid to lower continental slope out to oceanic crust at an average separation of 90 km along the margin and have an aver- age length of about 320 km. As well as providing excel- lent definition of the sedimentary section, the data also show structure as deep as the base of the crust, particu- larly over the outermost part of the continental margin. The shallow-penetration lines concentrating on the up- per continental rise and slope. Methods Each line was examined and the top of the rift phase of margin development was identified as the surface mark- ing the end of major fault deformation (Stagg et al., sub- mitted). The post-rift section was then classified accord- ing to sedimentary environment, based on reflector ge- ometries. This classification was not intended as a detailed Chapter 6.7 Post-Rift Continental Slope and Rise Sediments from 38° E to 164° E, East Antarctica Philip E. O’Brien · Shawn Stanley · Robert Parums Geoscience Australia, GPO Box 378 Canberra, 2601, Australia, <Phil.OBrien@ga.gov.au>