1887
ASEG2010 - 21st Geophysical Conference
  • ISSN: 2202-0586
  • E-ISSN:
PDF

Abstract

Summary

The deepwater Otway and Sorell basins developed during the breakup of Gondwana when Australia rifted from Antarctica. Regional 2D and 3D gravity modelling in conjunction with seismic and geological interpretation has led to an improved understanding of basement architecture in the study area. 2D gravity modelling along selected seismic lines reveals a N-S crustal-scale lineament extending to the Moho. A distinct density contrast of 0.16 t/m3 (i.e., between 3.05 t/m3 and 2.91 t/m3) across the structure points to significant lithological changes at middle to lower crustal depths, interpreted here to reflect a change from dominantly mafic to felsic lower crust. This structure is interpreted to be inherited from a pre-existing basement structure and supports the hypothesis that the evolution of the Sorell Basin was influenced by this basement structure. The 2D models also infer the presence of mafic under-plating in the lower-crust.

The computed 3D gravitational response derived from interpreted seismic data correlates moderately well to the observed gravity interpretation and (a) implies consistency between the seismic and gravity response of the interpreted model, and (b) delineates the basement topography and identifies possible depocentres. The independently-derived depth to magnetic basement map supports the 3D forward gravity modelling results.

© 2010 ASEG
Loading

Article metrics loading...

/content/journals/10.1081/22020586.2010.12041970
2010-12-01
2026-01-13

  • From This Site

    /content/journals/10.1081/22020586.2010.12041970
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. Dix, C.H., 1955. Seismic velocities from surface measurements. Geophysics, 20, 68–86.
  2. Foster, D.A., Gray, D.R., Spaggiari, C., Kamenov, G. and Bierlein, F.P. 2009. Palaeozoic Lachlan orogen, Australia; accretion and construction of continental crust in a marginal ocean setting: isotopic evidence from Cambrian metavolcanic rocks. In: Cawood, P.A & Kroner, A. (eds), Earth Accretionary System in Space and Time, Geological Society London Special Publication., 318, 329–349.
  3. Hill, P.J., Meisner, A.J., Moore, A.M.G. and Exon, N.F., 1997. Structure and development of west Tasmanian offshore sedimentary basins: Results of recent marine and aeromagnetic surveys. Aus. Jour. of Earth Sciences, 44, 579– 596.
  4. Gibson, G.M., Morse, M.P., Nayak, G.K., Stacey, A.R., Mitchell, C.H. and Totterdell, J.M., this Volume. Basement architecture and formation of an ocean-continent transform boundary off western Tasmania: insights from aeromagnetic and seismic reflection data collected from a frontier petroleum province. This Volume.
  5. Krassay, A.A, Cathro, D.L. and Ryan, D.J., 2004. A regional tectonostratigraphic framework for the Otway Basin, PESA Eastern Australasian basins Symposium II, 97-116.
  6. Kusznir, N., 2009. Set of digital grids of crustal thickness, Moho depth, thinning factor and residual continental crust for South Australia and Antarctica conjugate rifted margins resulting from satellite gravity inversion. Report to Geoscience Australia, https://www.ga.gov.au/products/servlet/controller?event= GEOCAT_DETAILS&catno=68656
  7. Morse, M.P., Gibson, G. M. and Mitchell, C. H., 2009, Basement constraints on offshore basin architecture as determined by new aeromagnetic data acquired over Bass Strait and western margin of Tasmania, AESG Expanded abstract, Adelaide
  8. Moore, A.M.G., Stagg, H.M.J. and Norvick, M.S., 2000. Deep water Otway Basin: a new assessment of the tectonics and hydrocarbon prospectivity. The APPEA Journal, 32, 66–85.
  9. Nayak,G.K., Rama Rao Ch., 2002. Structural configuration of Mahanadi offshore basin, India: an aeromagnetic study. Mar. Geophys. Res. 23, 471–479.
  10. Nolan, D., 2001. Field Report 2D Seismic Survey, Sorell Basin, Phase 1 for Seismic Australia. Report No. 34823.36. FUGRO-GEOTEM AS. OSLO. Unpublished Report.
  11. O’Brien, G.W., Tingate, P.R., Blevin, J.E., Boreham, C.J., Mitchell, A., Calver, C. and Williams, A. 2004. Hydrocarbon generation, migration, leakage and seepage on the West Tasmanian Margin, PESA Eastern Australasian Basins Symposium II, 19–22.
  12. Petkovic, P., 2004. Time-depth functions for the Otway Basin, Geoscience Australia Record 2004/02.
  13. Spector, A. and Grant, F.S., 1970. Statistical model for interpreting aeromagnetic data. Geophysics, 35, 293–302.
  14. Webring, M., 1985. SAKI: A Fortran program for generalized linear inversion of gravity and magnetic profiles. U.S. Geol. Surv. Open File Rep., 85–122.
  15. Wikmark, F., 2001. Field Report 2D Seismic Survey, Sorell Basin, Phase 2 for Seismic Australia. Report No. 34860.36. FUGRO-GEOTEM AS. OSLO. Unpublished Report.
/content/journals/10.1081/22020586.2010.12041970
Loading
  • Article Type: Research Article
Keyword(s): 2D modelling; 3D modelling; magnetic basement; underplating,

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error