1887
Volume 28, Issue 1-2
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

The generally accepted model of a 95 Ma breakup event in the Otway Basin has several unresolved inconsistencies, including evidence of significant post-95 Ma aged crustal extension. An alternative model is proposed: oceanic breakup took place at the end of the Late Cretaceous. A phase of extension during the pre-Aptian was followed by thermal subsidence before renewal of rifting (Cenomanian). Rifting of the already attenuated crust allowed the region to subside below sea level, resulting in marginal to nearshore marine conditions throughout most of the Late Cretaceous.

Continental breakup in the Late Maastrichtian (approximately 67 Ma) was marked by regional uplift along the northern basin margin, and towards the incipient continent-ocean boundary. This uplift is parallel to the present-day shelf. The age of this event is derived from palynological and seismic interpretations, and is consistent with previous thermochronological work. Broad anticlinal features on the basin margin may be associated with ridge-push associated with early oceanic crust development.

The first post-rift depositional cycle was during the latest Maastrichtian. A significant transgression flooded a peneplain (67 Ma unconformity surface). A maximum flooding surface was developed near the Cretaceous/Tertiary boundary, with subsequent highstand deposition developed through most of the basin. A second unconformity marks a depositional hiatus at the end of the deposition of this sequence.

Later cycles of post-rift sedimentation began in the Late Paleocene (55 Ma) with deposition of the ‘Wangerrip Megasequence’. Several eustatic sequences were deposited in a deltaic environment during the subsequent 8 million years.

© 1997 ASEG
Loading

Article metrics loading...

/content/journals/10.1071/EG997252
1997-03-01
2026-01-18

  • From This Site

    /content/journals/10.1071/EG997252
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. AGSO, 1996, An Australian Phanerozoic timescale. G.C. Young and J.R. Laurie eds. Oxford University Press, Great Britain.
  2. Arditto, P. A., 1995, The eastern Otway Basin Wangerrip Group revisited using an integrated sequence stratigraphic methodology: Australian Petroleum Exploration Association Journal 35, 372-384.
  3. Cande, S.C. and Mutter, J.C., 1982, A revised identification of the oldest sea-floor spreading anomalies between Australia and Antarctica: Earth and Planetary Science Letters 58, 151-160.
  4. Cooper, G.T., 1994, Vitrinite reflectance measurements and thermal modelling of samples from drill holes Ross Creek-1, Purrumbete-1 and Garvoc-1: Geological Survey of Victoria Report 1994/14 (unpublished).
  5. Cooper, G.T., 1995, Seismic structure and extensional development of the Eastern Otway Basin-Torquay Embayment: Australian Petroleum Exploration Association Journal 35, 436-450.
  6. Duddy. I.R., 1994, The Otway Basin: thermal, tectonic and hydrocarbon generation histories, pp. 35-42. In Finlayson, D.M., ed., NGMA/PESA Otway Basin Symposium, Melbourne, extended abstracts; AGSO Record 1994/14 (unpublished).
  7. Exon, N.F., 1994, Continental and oceanic crust mapping west and south of Tasmania: AGSO Research Newsletter 21. 5-7.
  8. Falvey, D.A., 1974, The development of continental margins in plate tectonic theory: Australian Petroleum Exploration Association Journal 14, 95-106.
  9. Hill, K.A. and Durrand, C, 1993, The western Otway Basin an overview of the rift and drift history using serial composite seismic profiles: PESA Journal 21, 64-78.
  10. Hill, K.C., Cooper, G.T. and Mitchell, M.M., 1994, Burial, heat pulses, inversion and denudation in the Otway Basin, pp. 49-54. In Finlayson, D.M., ed., NGMA/PESA Otway Basin Symposium, Melbourne, extended abstracts; AGSO Record 1994/14 (unpublished).
  11. Hill, K.A., Finlayson, D.M., Hill, K.C. and Cooper, G.T, 1995, Mesozoic tectonics of the Otway Basin region: the legacy of Gondwana and the active Pacific margin a review and ongoing research: Australian Petroleum Exploration Association Journal 35, 467-493.
  12. Hill, P.J., Exon, N.F. and Royer, J.Y., 1995, Swath-mapping the Australian continental margin: Results from offshore Tasmania: Exploration Geophysics 26, 403-411.
  13. Kopsen, E. and Scholefield, T, 1990, Prospectivity of the Otway Supergroup in the central and western Otway Basin: Australian Petroleum Exploration Association Journal 30, 263-279.
  14. Morton, J.G.G, Hill, A.J., Parker, G. and Tabassi, A., 1994, Towards a unified stratigraphy for the Otway Basin, pp. 7-12. In Finlayson, D.M., ed., NGMA/PESA Otway Basin Symposium, Melbourne, extended abstracts; AGSO Record 1994/14 (unpublished).
  15. Smith, M.A. and Donaldson, I.F. 1995, The hydrocarbon potential of the Duntroon Basin: APEAJournal 35, 203-219.
  16. Stagg, H.M. and Willcox, J.B., 1992, A case for Australia-Antarctic separation in the Neocomian (ca. 125 Ma): Tectonophysics 210, 21-22.
  17. United States Geological Survey (USGS), 1991, Tectonic map of the Circum-Pacific region: southwest quadrant: The United States Geological Survey, United States of America.
  18. Veevers, J.J., 1986, Break-up of Australia and Antarctica estimated from magnetic and seismic data at the continental margin: Earth and Planetary Science Letters 77, 91-99.
  19. Veevers, J.J., 1988, Seafloor magnetic lineation off the Otway/West Tasmania Basins: ridge jumps and the subsidence history of the southeast Australian margins: Australian Journal of Earth Sciences 35, 451-462.
  20. Williamson, P.E., OșBrien, G.W., Swift, M.G., Felton, E.A., Scherl, A.S., Lock, J., Exon, N.F., Falvey, D.A. and Marlow, M., 1987, Hydrocarbon potential of the offshore Otway Basin: Australian Petroleum Exploration Association Journal 27, 173-194.
/content/journals/10.1071/EG997252
Loading
  • Article Type: Research Article
Keyword(s): continental breakup; Otway Basin; seismic; sequence stratigraphy; Sherbrook Group; thermochronology; Wangerrip Group

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