Pre‐ to syn‐tectonic emplacement of early Palaeozoic granites in southeastern South Australia

1977 ◽  
Vol 24 (1-2) ◽  
pp. 87-106 ◽  
Author(s):  
A. R. Milnes ◽  
W. Compston ◽  
B. Daily
Keyword(s):  
South Australia ◽  
Early Palaeozoic

PREDICTION OF CARBONATE RESERVOIRS AND TRAPS BY APPLYING SEQUENCE STRATIGRAPHY IN THE EASTERN WARBURTON BASIN, SOUTH AUSTRALIA

1998 ◽  
Vol 38 (1) ◽  
pp. 380 ◽  
Author(s):  
X.W. Sun
Keyword(s):  
Seismic Reflection ◽  
South Australia ◽  
High Amplitude ◽  
Carbonate Reservoirs ◽  
Source Rocks ◽  
Shelf Edge ◽  
Secondary Porosity ◽  
Sandy Limestone ◽  
Potential Reservoir ◽  
Early Palaeozoic

The Early Palaeozoic eastern Warburton Basin unconformably underlies the Cooper and Eromanga Basins. Four seismic sequence sets (I−IV) are interpreted. Among them, sequence set II is subdivided into four Cambro-Ordovician depositional sequences. Sequence 1, the oldest, is a shallow shelf deposit that occurs only in the Gidgealpa area. Sequences 2 and 3 were deposited in a wider area; from west to east, environments varyied from deep siliciclastic ramp, carbonate inner-shelf, peritidal, shelf edge, and slope-to-basin. Their seismic reflection configurations are high-amplitude, regionally parallel-continuous, layered patterns, locally mounded geometry, as well as divergent-fill patterns. Sequence 4, the youngest, was deposited in a mixed siliciclastic and carbonate, storm-dominate shelf. Its seismic reflection configurations are moderate amplitude, parallel-layered patterns, decreasing in amplitude upwards.Boundaries between the four sequences generated good secondary porosity in the carbonates. Karst development is interpreted to have generated much of this porosity in shelf and peritidal carbonates, and carbonate build-ups. Shoal-water sandy limestone and calcareous sandstone of Sequence 4 may be other potential reservoir rocks. Potential source rocks comprise mudstone and shale of slope and basin lithofacies. There are two kinds of stratigraphic trap. One is in Sequences 2 and 3, associated with high-relief carbonate build-ups encased in lagoonal mudstone and shelf edge sealed by transgressive siltstone and shale. The other is a transgressive marine shale enclosing porous dolostone of the karstified Sequence 1. In addition, petroleum may have migrated from Permian source rocks of the Cooper Basin to karstified carbonate reservoirs of the Warburton Basin at unconformities.

Reassessment of the seismic stratigraphy of the Early Palaeozoic Stansbury Basin, Gulf St Vincent, South Australia

1998 ◽  
Vol 45 (4) ◽  
pp. 547-557 ◽  
Author(s):  
T. Flöttmann ◽  
P. W. Haines ◽  
C. D. Cockshell ◽  
W. V. Preiss
Keyword(s):  
South Australia ◽  
Seismic Stratigraphy ◽  
Early Palaeozoic

Preservation of late Palaeozoic glacial rock surfaces by burial prior to Cenozoic exhumation, Fleurieu Peninsula, southeastern Australia

2021 ◽  
pp. jgs2020-250
Author(s):  
Simon P. Holford ◽  
Paul F. Green ◽  
Ian R. Duddy ◽  
Richard R. Hillis ◽  
Steven M. Hill ◽  
...  
Keyword(s):  
Sedimentary Cover ◽  
South Australia ◽  
Early Permian ◽  
Glacial Erosion ◽  
Metasedimentary Rocks ◽  
Southeastern Australia ◽  
Australian Continent ◽  
Geomorphic Features ◽  
Granitic Intrusions ◽  
Early Palaeozoic

The antiquity of the Australian landscape has long been the subject of debate, with some studies inferring extraordinary longevity (>108 Myr) for some subaerial landforms dating back to the early Palaeozoic. A number of early Permian glacial erosion surfaces in the Fleurieu Peninsula, southeastern Australia, provide an opportunity to test the notion of long-term subaerial emergence, and thus tectonic and geomorphic stability, of parts of the Australian continent. Here we present results of apatite fission-track analysis (AFTA) applied to a suite of samples collected from localities where glacial erosion features of early Permian age are developed. Our synthesis of AFTA results with geological data reveals four cooling episodes (C1-4), which are interpreted to represent distinct stages of exhumation. These episodes occurred during the Ediacaran to Ordovician (C1), mid-Carboniferous (C2), Permian to mid-Triassic (C3) and Eocene to Oligocene (C4).The interpretation of AFTA results indicates that the Neoproterozoic-Lower Palaeozoic metasedimentary rocks and granitic intrusions upon which the glacial rock surfaces generally occur were exhumed to the surface by the latest Carboniferous-earliest Permian during episodes C2 and/or C3, possibly as a far-field response to the intraplate Alice Springs Orogeny. The resulting landscapes were sculpted by glacial erosive processes. Our interpretation of AFTA results suggests that the erosion surfaces and overlying Permian sedimentary rocks were subsequently heated to between ∼60 and 80°C, which we interpret as recording burial by a sedimentary cover comprising Permian and younger strata, roughly 1 kilometre in thickness. This interpretation is consistent with existing thermochronological datasets from this region, and also with palynological and geochronological datasets from sediments in offshore Mesozoic-Cenozoic-age basins along the southern Australian margin that indicate substantial recycling of Permian-Cretaceous sediments. We propose that the exhumation which led to the contemporary exposure of the glacial erosion features began during the Eocene to Oligocene (episode C4), during the initial stages of intraplate deformation that has shaped the Mt Lofty and Flinders Ranges in South Australia. Our findings are consistent with several recent studies, which suggest that burial and exhumation has played a key role in the preservation and contemporary re-exposure of Gondwanan geomorphic features in the Australian landscape.

scholarly journals Absence of evidence for Palaeoproterozoic eclogite-facies metamorphism in East Antarctica: no record of subduction orogenesis during Nuna development

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dillon A. Brown ◽  
Laura J. Morrissey ◽  
John W. Goodge ◽  
Martin Hand
Keyword(s):  
Plate Boundary ◽  
South Australia ◽  
East Antarctica ◽  
Geological Evidence ◽  
Crustal Shortening ◽  
Eastern Margin ◽  
Facies Metamorphism ◽  
Eclogite Facies ◽  
Early Palaeozoic ◽  
Collisional Orogenesis

AbstractThe cratonic elements of proto-Australia, East Antarctica, and Laurentia constitute the nucleus of the Palaeo-Mesoproterozoic supercontinent Nuna, with the eastern margin of the Mawson Continent (South Australia and East Antarctica) positioned adjacent to the western margin of Laurentia. Such reconstructions of Nuna fundamentally rely on palaeomagnetic and geological evidence. In the geological record, eclogite-facies rocks are irrefutable indicators of subduction and collisional orogenesis, yet occurrences of eclogites in the ancient Earth (> 1.5 Ga) are rare. Models for Palaeoproterozoic amalgamation between Australia, East Antarctica, and Laurentia are based in part on an interpretation that eclogite-facies metamorphism and, therefore, collisional orogenesis, occurred in the Nimrod Complex of the central Transantarctic Mountains at c. 1.7 Ga. However, new zircon petrochronological data from relict eclogite preserved in the Nimrod Complex indicate that high-pressure metamorphism did not occur in the Palaeoproterozoic, but instead occurred during early Palaeozoic Ross orogenesis along the active convergent margin of East Gondwana. Relict c. 1.7 Ga zircons from the eclogites have trace-element characteristics reflecting the original igneous precursor, thereby casting doubt on evidence for a Palaeoproterozoic convergent plate boundary along the current eastern margin of the Mawson Continent. Therefore, rather than a Palaeoproterozoic (c. 1.7 Ga) history involving subduction-related continental collision, a pattern of crustal shortening, magmatism, and high thermal gradient metamorphism connected cratons in Australia, East Antarctica, and western Laurentia at that time, leading eventually to amalgamation of Nuna at c. 1.6 Ga.

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