Abstract
In 2001 and 2002, the Australian Government acquired approximately 9 000 km of high-quality geophysical data over the margin of East Antarctica between 110–142° E that provide a sound framework for understanding the geology of the region. The data comprise 36-fold deep-seismic, gravity and magnetic data and non-reversed refraction/wide-angle reflection sonobuoys recorded along transects that extend from the lower continental slope out to oceanic crust at a spacing along the margin of approximately 90 km. The continental slope is underlain by a major rift basin beneath which the crust thins oceanwards through extensive faulting of the rift and pre-rift sedimentary section and by mainly ductile deformation of the crystalline crust. Outboard of the margin rift basin, the 90 to 180 km wide continent-ocean transition zone is interpreted to consist primarily of continental crust with magmatic components that can account for the lineated magnetic anomalies that have been interpreted in this zone. The thick sedimentary section in the COT zone is floored by dense lower crustal or mantle rocks indicating massive (>10 km) thinning of the lower and middle crust in this zone. The boundary between the margin rift basin and the COT is marked by a basement ridge which potential field modelling indicates is probably composed of altered/serpentinised peridotite. This ridge is similar in form and interpreted composition to a basement ridge located in a similar structural position at the inboard edge of the COT on the conjugate margin of the Great Australian Bight. On both margins, the ridge is probably the product of mantle up-welling and partial melting focussed at the point of maximum change/necking of crustal thickness. Integrated deep-seismic and potential field interpretations point very strongly to the boundary between unequivocal oceanic crust and largely continental crust of the continent-ocean transition as lying in very deep water, and considerably seaward of most previous interpretations (often based on inadequate seismic data or magnetic data only). We consider the continent-ocean boundary to be well-constrained from 124–131° E and unequivocal from 131–140° E, but open to debate in the sector from 110–124° E. There is a strong degree of pre-breakup symmetry between the conjugate margins of southern Australia and East Antarctica east of about 120° E. In addition to the crustal symmetry, there is also a strong correlation in seismic character between the margins, which allows us to date the major unconformities as probably of base Turonian, Maastrichtian and early Middle Eocene age.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Eittreim SL, Hampton MA (eds) (1987) The Antarctic continental margin: geology and geophysics of offshore Wilkes Land. Earth Science Series, Circum-Pacific Council for Energy and Resources, 5A
Eittreim SL, Smith GL (1987) Seismic sequences and their distribution on the Wilkes Land margin. In: Eittreim SL, Hampton MA (eds) The Antarctic continental margin: geology and geophysics of offshore Wilkes Land. Earth Science Series, Circum-Pacific Council for Energy and Resources, 5A, pp 15–43
Finlayson DM, Lukaszyk I, Collins CDN, Chudyk EC (1998) Otway Continental Margin Transect: crustal architecture from wide-angle seismic profiling across Australia’s southern margin. Australian J Earth Sci 45:717–732
Hinz K, Willcox JB, Whiticar M, Kudrass HR, Exon NF, Feary DA (1986) The west Tasmanian margin: an underrated petroleum province? In: Glenie RC (ed) Second south-eastern Australia oil exploration symposium 1985. Petrol Explor Soc Australia, Melbourne, pp 395–410
Hopkinson L, Beard JS, Boulter CA (2004) The hydrothermal plumbing of a serpentinite-hosted detachment: evidence from the West Iberia non-volcanic rifted continental margin. Marine Geology 204:301–315
Ishihara T, Tanahashi M, Sato M, Okuda Y (1996) Preliminary report of geophysical and geological surveys of the west Wilkes Land margin. Proc NIPR Symp Antarc Geosci 9: 91–108
Kanep AG (1975) Cenozoic planktonic foraminifera from Antarctic deep-sea sediments, Leg 28, DSDP. In: Hayes DE, Frakes LA, et al. (eds) Initial Rep Deep Sea Drilling Project, U.S. Government Printing Office, Washington DC, 28:573–584
Miller JMcL, Norvick MS, Wilson CJL (2002) Basement controls on rifting and the associated formation of ocean transform faults — Cretaceous continental extension of the southern margin of Australia. Tectonophysics 359:131–155
Moore AMG, Stagg HMJ, Norvick MS (2000) Deep-water Otway basin: a new assessment of the tectonics and hydrocarbon prospectivity. APPEA J 40:66–84
Muentener O, Herrmann J (2001) The role of lower crust and continental upper mantle during formation of non-volcanic passive margins: evidence from the Alps. In: Wilson RCL, Whitmarsh RB, Froitzheim N (eds) Non-volcanic rifting of continental margins: a comparison of evidence from land and sea. Geol Soc London, Spec Publ 187:267–288
O’Brien PE, Stanley S (2003) Cainozoic continental slope and rise sediments from 38° E to 164° E, East Antarctica. In: Fütterer DK (ed) Antarctica: contributions to global earth science. Abstracts 9th ISAES Potsdam, Terra Nostra 246
Perez-Gussinyé M, Reston TJ (2001) Rheological evolution during extension at nonvolcanic rifted margins: onset of serpentinization and development of detachments leading to continental breakup. J Geophys Res 106(3):961–3975
Reston TJ, Pennell J, Stubenrauch A, Walker I, Perez-Gussinyé M (2001) Detachment faulting, mantle serpentinzation, and serpentinitemud volcanism beneath the Porcupine Basin, southwest Ireland. Geology 29:587–590
Sato S, Asakura N, Saki T, Oikawa N, Kaneda Y (1984) Preliminary results of geologiacal and geophysical surveys in the Ross Sea and in the Dumont d’Durville Sea, off Antarctica. Mem Nat Inst Polar Res Spec Issue 33:66–92
Sayers J, Symonds PA, Direen NG, Bernardel G (2001) Nature of the continent-ocean transition on the non-volcanic rifted margin of the central Great Australian Bight. In: Wilson RCL, Whitmarsh RB, Froitzheim N (eds) Non-volcanic rifting of continental margins: a comparison of evidence from land and sea. Geol Soc London Spec Publ 187:51–76
Stagg HMJ, Colwell JB, Direen NG, O’Brien PE, Brown BJ, Bernardel G, Borissova I, Carson L, Close DB (2005) Geological framework of the continental margin in the region of the Australian Antarctic Territory. Geosci Australia Record 2004/25
Stagg H, Schiwy S (2002) Marine geophysical surveys completed off Antarctica. Aus Geo News 66:18–19
Tanahashi M, Saki T, Oikawa N, Sato S (1987) An interpretation of the multichannel seismic reflection profiles across the continental margin of the Dumont d’Urville Sea, off Wilkes Land, East Antarctica. In: Eittreim SL, Hampton MA (eds) The Antarctic continental margin: geology and geophysics of offshore Wilkes Land. Earth Science Series, Circum-Pacific Council for Energy and Resources, 5A, pp 1–13
Tanahashi M, Ishihara T, Yuasa M, Murakami M, Nishimura A (1997) Preliminary report of the TH95 geological and geophysical survey results in the Ross Sea and Dumont d’Urville Sea. Proc NIPR Symp Antarc Geosci 10:36–58
Tikku AA, Cande SC (1999) The oldest magnetic anomalies in the Australian-Antarctic Basin: are they isochrons? J Geophys Res 101(1):661–677
Totterdell JM, Blevin JE, Struckmeyer HIM, Bradshaw BE, Colwell JB, Kennard JM (2000) A new sequence framework for the Great Australian Bight: starting with a clean slate. APPEA J 40(1):95–116
Tsumuraya Y, Tanahashi M, Saki T, Machihara T, Asakura N (1985) Preliminary report of the marine geophysical and geological surveys off Wilkes Land, Antarctica in 1983–1984. Mem Nat Inst Polar Res Spec Issue 37:48–62
Wannesson J, Pelras M, Petitperrin B, Perret M, Segoufin J (1985) A geophysical transect of the Adélie margin, East Antarctica. Marine Petrol Geol 2:192–201
Whitmarsh RB, Manatschal G, Minshull TA (2001) Evolution of magma-poor continental margins from rifting to seafloor spreading. Nature 413:150–154
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2006 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Colwell, J.B., Stagg, H.M.J., Direen, N.G., Bernardel, G., Borissova, I. (2006). The Structure of the Continental Margin off Wilkes Land and Terre Adélie Coast, East Antarctica. In: Fütterer, D.K., Damaske, D., Kleinschmidt, G., Miller, H., Tessensohn, F. (eds) Antarctica. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-32934-X_41
Download citation
DOI: https://doi.org/10.1007/3-540-32934-X_41
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-30673-3
Online ISBN: 978-3-540-32934-3
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)