 |
| Titel |
Re-evaluation of the Mentelle Basin, a polyphase rifted margin basin, offshore southwest Australia: new insights from integrated regional seismic datasets |
| VerfasserIn |
D. Maloney, C. Sargent, N. G. Direen, R. W. Hobbs, D. R. Gröcke |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1869-9510
|
| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 2, no. 2 ; Nr. 2, no. 2 (2011-07-07), S.107-123 |
| Datensatznummer |
250000587
|
| Publikation (Nr.) |
 copernicus.org/se-2-107-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
Vintage 2-D (two-dimensional) seismic reflection surveys from the sparsely
explored Mentelle Basin (western Australian margin) have been reprocessed
and integrated with a recent high-quality 2-D seismic survey and
stratigraphic borehole data. Interpretation of these data sets allows the
internal geometry of the Mentelle Basin fill and depositional history to be
reanalysed and new insights into its formation revealed. Basin stratigraphy
can be subdivided into several seismically defined megasequences separated
by major unconformities related to both breakup between India-Madagascar and
Australia-Antarctica in the Valanginian-Late Hauterivian and
tectonically-driven switches in deposition through the Albian.
Resting on the Valanginian-Late Hauterivian breakup unconformity are several
kilometre-scale mounded structures that formed during Late Jurassic to Early
Cretaceous extension. These have previously been interpreted as volcanic
edifices although direct evidence of volcanic feeder systems is lacking. An
alternative interpretation is that these features may be carbonate
build-ups. The latter interpretation carries significant climatic
ramifications since carbonate build-ups would have formed at high
palaeolatitude, ~60° S.
Soon after breakup, initial subsidence resulted in a shallow marine
environment and deposition of Barremian-Aptian silty-sandy mudstones. As
subsidence continued, thick successions of Albian ferruginous black clays
were deposited. Internally, seismic megasequences composed of successions of
black clays show previously unresolved unconformities, onlapping and
downlapping packages, which reflect a complex depositional, rifting and
subsidence history at odds with their previous interpretation as open marine
sediments.
Southwestwards migration of the Kerguelen hotspot led to thermal contraction
and subsidence to the present day water depth (~3000 m). This was
accompanied by Turonian-Santonian deposition of massive chalk beds, which
are unconformably overlain by pelagic Palaeocene-Holocene sediments. This
substantial unconformity is related to the diachronous breakup and onset of
slow spreading between Australia and Antarctica, which may have led to the
reactivation and inversion of basement faults and was followed by rapid
seafloor spreading from the Middle Eocene to the present. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|