Imaging the basement architecture across the Cork Fault in Queensland using magnetic and gravity data

Spampinato, Giovanni P.T.; Aillères, Laurent; Betts, Peter Graham; Armit, Robin

doi:10.1016/j.precamres.2015.04.002

Cited by 13 publications

(6 citation statements)

References 111 publications

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“…Both faults show juxtaposition of Late Neoproterozoic to Paleozoic rocks (Thomson Orogen crust in the hanging wall block) against Paleoproterozoic to Mesoproterozoic rocks (North Australian Craton crust in the foot‐wall block). These structural relationships suggest normal kinematics along the boundary between the North Australian Craton and the Thomson Orogen, consistent with the forward modeling of the potential field data by Spampinato et al (). However, at a shallower depth, the Cork Fault can be interpreted as a reverse fault, showing minor folding and small offset near the base of the Jurassic sedimentary package (Figure a).…”

Section: Resultssupporting

confidence: 87%

“…The Thomson Orogen extends from the Cork Fault in the west to the unexposed basement beneath the Permian East Australian Rift System in the east (Figure b). The Cork Fault, which represents the boundary between the Precambrian North Australian Craton and the Tasmanides (Glen, ; Veevers, ), has been interpreted as a reactivated structure that formed along the Neoproterozoic rifted margin of Rodinia (Spampinato et al, ; Spampinato, Betts, et al, ). Northeast of the Thomson Orogen, the Mossman Orogen (Figures b and c) is represented by the Silurian to Late Devonian Hodgkinson and Broken River provinces (Withnall & Henderson, ).…”

Section: Geological Settingmentioning

confidence: 99%

“…Geophysical data indicate that the southern Thomson Orogen is underlain by a thick (~40–45 km) crust (Abdullah & Rosenbaum, ; Glen et al, ), but the central and northern parts of the orogen are characterized by a relatively thin layered crust (Finlayson, ; Finlayson, Leven, et al, ; Finlayson, Wake‐Dyster, et al, ; Glen, ; Korsch et al, ; Milligan et al, ; Murray & Finlayson, ; Spampinato et al, ). The nature of this basement, however, is unknown, because of the presence of sedimentary cover.…”

Section: Introductionmentioning

confidence: 99%

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Devonian Crustal Stretching in the Northern Tasmanides (Australia) and Implications for Oroclinal Bending

Abdullah

Rosenbaum

2018

JGR Solid Earth

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The Tasmanides in eastern Australia exhibit a number of orogenic curvatures (oroclines), and possibly, a continental‐scale bend that defines the continuation of the Delamerian Orogen with the Thomson Orogen. We provide an insight into the geodynamic processes associated with the origin of this orocline. We present interpretations of seismic reflection profiles and potential field data from the Thomson Orogen, which provide information on the crustal architecture and unravel major structures and kinematic relationships. Results show that a large area in the northern Tasmanides is underlain by thinned crust, bounded in the north and south by ~E‐W trending geophysical features with apparent sinistral and dextral sense of kinematics, respectively. Within the highly extended crust of the Thomson Orogen, there is evidence for widespread Devonian basins bounded by normal faults. In stark contrast to the southern Tasmanides, where rocks show evidence for an earlier (Silurian) episode of extension and Devonian contractional deformation, no evidence for Silurian synrift sedimentation is observed in the Thomson Orogen. Evidence for ~E‐W trending sinistral and dextral crustal‐scale shear zones in the northern and southern boundaries of the Thomson Orogen, respectively, may represent tear faults, which were active during the Early Devonian and were possibly accompanied by tear‐related magmatism. We suggest that crustal stretching in the northern Tasmanides was associated with Devonian back‐arc extension in response to trench retreat, bounded by zones of slab‐tearing and crustal segmentation that ultimately led to the development of the Delamerian‐Thomson Orocline.

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Section: Resultssupporting

confidence: 87%

Section: Geological Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Devonian Crustal Stretching in the Northern Tasmanides (Australia) and Implications for Oroclinal Bending

Abdullah

Rosenbaum

2018

JGR Solid Earth

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“…In this context, the high density and magnetic lower crust of the Thomson Orogen can be formed-at least in part-by a Grenvilleaged belt, which extends from the Musgrave Block in the sub-surface. Spampinato et al (2015b) indicated that the lower basement crust of the Thomson Orogen is petrophysically indistinguishable from the adjacent Mount Isa basement crust. In their view, the Mount Isa crust may be-at least in part-represented under the Thomson Orogen and would correspond to the thinned and magnetic lower crust.…”

Section: Thomson Orogen Vs Mount Isa Terranementioning

confidence: 99%

“…This may represent an issue with either a clockwise rotation ( Figure 12B) (Li & Evans 2011) or counter-clockwise rotation ( Figure 12C) (Harrington 1974;Musgrave 2013;Glen et al 2014), which would have created the accommodation space in the Thomson Orogen during the late NeoproterozoicÀearly Cambrian. This implies that either the rotation models need to be readdressed or the prominent NE-trending geophysical signature of the region is related to a post-550 Ma event, although it is implicit from Li & Evans's (2011) model and many other geodynamic reconstructions (Finlayson et al 1988;Giles et al 2004;Gibson et al 2008;Williams et al 2010;Henson et al 2011;Spampinato et al 2015b) that the NEtrending Cork Fault is a pre-550 Ma structure.…”

Section: Thomson Orogen Vs Mount Isa Terranementioning

confidence: 99%

Crustal architecture of the Thomson Orogen in Queensland inferred from potential field forward modelling

Spampinato

Aillères

Betts

et al. 2015

Australian Journal of Earth Sciences

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The basement rocks of the poorly understood Thomson Orogen are concealed by mid-Paleozoic to Upper Cretaceous intra-continental basins and direct information about the orogen is gleaned from sparse geological data. Constrained potential field forward modelling has been undertaken to highlight key features and resolve deeply sourced anomalies within the Thomson Orogen. The Thomson Orogen is characterised by long-wavelength and low-amplitude geophysical anomalies when compared with the northern and western Precambrian terranes of the Australian continent. Prominent NE-and NW-trending gravity anomalies reflect the fault architecture of the region. High-intensity Bouguer gravity anomalies correlate with shallow basement rocks. Bouguer gravity anomalies below À300 mm/s 2 define the distribution of the Devonian Adavale Basin and associated troughs. The magnetic grid shows smooth textures, punctuated by short-wavelength, high-intensity anomalies that indicate magnetic contribution at different crustal levels. It is interpreted that meta-sedimentary basement rocks of the Thomson Orogen, intersected in several drill holes, are representative of a seismically non-reflective and non-magnetic upper basement. Short-wavelength, high-intensity magnetic source bodies and colocated negative Bouguer gravity responses are interpreted to represent shallow granitic intrusions. Long-wavelength magnetic anomalies are inferred to reflect the topography of a seismically reflective and magnetic lower basement. Potential field forward modelling indicates that the Thomson Orogen might be a single terrane. We interpret that the lower basement consists of attenuated Precambrian and mafic enriched continental crust, which differs from the oceanic crust of the Lachlan Orogen further south.

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Magnetic anomalies of randomly magnetized finite-strike listric fault sources

Deepak,

Ramamma,

Chakravarthi

2024

J Earth Syst Sci

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Imaging the basement architecture across the Cork Fault in Queensland using magnetic and gravity data

Cited by 13 publications

References 111 publications

Devonian Crustal Stretching in the Northern Tasmanides (Australia) and Implications for Oroclinal Bending

Devonian Crustal Stretching in the Northern Tasmanides (Australia) and Implications for Oroclinal Bending

Crustal architecture of the Thomson Orogen in Queensland inferred from potential field forward modelling

Magnetic anomalies of randomly magnetized finite-strike listric fault sources

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