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Tectonic Evolution and Continental Fragmentation of the Southern West Australian Margin
Citation
Whittaker, J and Halpin, JA and Williams, SE and Hall, LS and Gardner, R and Kobler, ME and Daczko, NR and Muller, RD, Tectonic Evolution and Continental Fragmentation of the Southern West Australian Margin, The Sedimentary Basins of Western Australia IV: Proceedings of the Petroleum Exploration Society of Australia Symposium, 18-21 August 2013, Perth, WA, pp. 1-18. (2013) [Refereed Conference Paper]
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Abstract
Continental rocks dredged in 2011 show that the Batavia
Knoll and Gulden Draak Knoll, two prominent bathymetric
features located ~1600 km offshore Perth, are micro-continents.
Plate tectonic modeling reconstructs the pre-rift position of
these knolls to the north and south of the Naturaliste Plateau,
respectively. The Batavia Knoll was conjugate to part of the
northern Naturaliste Plateau, while the Gulden Draak Knoll
was conjugate to the western Bruce Rise, Antarctica. Here,
we compare basement rocks, patterns of sedimentation,
volcanism and structure on the better studied Naturaliste
Plateau, Mentelle Basin and Bruce Rise with newly collected
data from the knolls. Significant volumes of metamorphic and
granitic basement rocks were dredged from both the Batavia
and Gulden Draak knolls. Preliminary geochronological and
geochemical analyses show that these rocks are continental in
nature and include protolith granitoids that were emplaced
during the Archaean (~2850 Ma) and the Mesoproterozoic
(~1290–1200 Ma) (Gulden Draak Knoll), and during the Early
Palaeozoic (~540–530 Ma) (Batavia Knoll). All metamorphic
rocks were invariably reworked during the Kuunga Orogeny
(~550–500 Ma) during the final assembly of Gondwana.
Sediment accumulations are generally relatively thin (up
to a few hundred meters) on all the continental fragments,
with the exception of NNE to NE oriented rift basins with
up to ~2 km of sediments. Sedimentary rocks, predominantly
sandstones were dredged from adjacent to the interpreted
rift basin locations on both the Batavia and Gulden Draak
knolls. Volcanic/intrusive material has been interpreted on the
northern flank of the Naturaliste Plateau from seismic profiles,
but no basalts were found in either of the Batavia Knoll
dredges. Extensive volcanism has also been interpreted on
both the Naturaliste Plateau and Bruce Rise. Volcanic material
was dredged in one of two sites on the Gulden Draak Knoll,
and geophysical data may support the presence of an igneous
domain. The structural, volcanic and sedimentary nature of
the knolls will be tested in late-2014 with the collection of
new magnetic, gravity, seismic reflection and dredge data.
Item Details
| Item Type: | Refereed Conference Paper |
|---|---|
| Keywords: | plate tectonics |
| Research Division: | Earth Sciences |
| Research Group: | Geology |
| Research Field: | Tectonics |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding Knowledge |
| Objective Field: | Expanding Knowledge in the Earth Sciences |
| UTAS Author: | Whittaker, J (Associate Professor Jo Whittaker) |
| UTAS Author: | Halpin, JA (Dr Jacqueline Halpin) |
| ID Code: | 86218 |
| Year Published: | 2013 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2013-08-29 |
| Last Modified: | 2014-09-11 |
| Downloads: | 3 View Download Statistics |
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