Crustal Studies of South Australia Based on Energy Spectral Analysis of Regional Magnetic Data

Kivior, Irena; Shi, Zhenyu; Boyd, D.; McClay, K. R.

doi:10.1071/eg993603

Cited by 9 publications

(3 citation statements)

References 11 publications

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“…Crustal thickness of the Adelaide Geosyncline has been shown via seismic and potential field methods to be quite uniform over the region with a range of 26–30 km (Mumme 1961; Shackleford & Sutton 1981; Greenhalgh et al 1989a, b; Kivior et al 1993).…”

Section: Geological Settingmentioning

confidence: 99%

3-D seismic tomography of the Adelaide fold belt

Clifford¹,

Greenhalgh²,

Houseman³

et al. 2008

Geophysical Journal International

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S U M M A R YA lithospheric tomography experiment was conducted in the Adelaide Fold Belt of South Australia, to elucidate the 3-D velocity structure down to depths of several hundred kilometres in a region of major geological and tectonic significance. The data comprised arrival times for compressional waves from 148 teleseismic events recorded on a temporary array of 40 digital seismographs spanning an area of 200 × 300 km. A new irregular shortest path ray tracer and non-linear inversion scheme were used to map the crust-and upper-mantle structure. Synthetic 3-D imaging tests were first performed to validate the procedure and establish resolution limits for the particular earthquake distribution and recording geometry.Wave speed anomalies of up to 4 per cent relative to the IASP91 layered earth model were found. The boundary between a prominent velocity high and a prominent velocity low in the shallow (crustal) depth slices seems to coincide with the synclinal axis of Adelaidean and Early Palaeozoic sediments. Other velocity features at shallow depths correlate with gravity highs and lows, and compare favourably with structure revealed from explosion seismic profiles recorded in the area. At depths greater than 60 km, the tomographic images reveal isolated velocity highs enclosed by regions of lower velocity within the fold belt. These features, of dimensions tens of kilometres, could indicate the existence of fragments of old mantle broken off from the thick subcontinental lithosphere beneath the Gawler Craton and scattered in the Rodinian break-up rift zone.

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Section: Geological Settingmentioning

confidence: 99%

3-D seismic tomography of the Adelaide fold belt

Clifford¹,

Greenhalgh²,

Houseman³

et al. 2008

Geophysical Journal International

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“…The intension of our study is to characterize the source depth by numerical integrations and to obtain slabs at depths. The method of obtaining depths was appropriately formulated by previous studies through proper spectra in which the grids were obtained and plotted (Spector, Grant, 1970;Kivior, 1996;Meixner, Jonston, 2012). The concept of equivalent sources was also found significant in modeling the potential field.…”

Section: Introductionmentioning

confidence: 99%

Magnetic constraints and susceptible inversions of Balapur Fault at central Kashmir Basin, NW Himalaya

Dar

Bukhari

2023

Lithosphere

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Research subject. Subsurface investigations of the Balapur Fault at central Kashmir Basin, NW Himalaya through groundmagnetic surveys and data interpretations. Materials and methods. The total magnetic intensity data was obtained using ground magnetic surveys carried out by proton precession magnetometers at 15 m spacing. The magnetic constraints and inversions of the Balapur fault in the central Kashmir basin of NW Himalaya were analyzed. Results. The total magnetic intensity was found averaging at 97.7 with 45.8 nT as magnetic minima and 140.9 nT as magnetic maxima. The minima’s ranging from 45.8 and 55.8 nT in the gridded profile are inferred at the Balapur fault. Further, the fault-related susceptibility index was recorded from 0.0035 SI to 0.0015 SI, and the observed and predicted response values were found ranging between 67.1 to 87.7 and 67.4 to 86.6 nT respectively. Conclusion. The study suggests that the Balapur fault in the central Kashmir has produced high subsurface hydraulic activities and, therefore, evident low magnetic anomalies. The analysis reveals a thick minima region related to the fault and also indicated the presence of associated structures with the main Balapur fault segment.

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“…The multi-window test procedure (ESA-MWT) (Kivior et al, 1993, Kivior et al, 2011) is applied to detect magnetic susceptibility contrasts at different depths that correspond to magnetic interfaces. ESA-MWT detects contrasts between stronger magnetic sediments overlaid by less magnetic material and magnetic basement covered by less magnetic sediments.…”

Section: Horizon Mappingmentioning

confidence: 99%

Mapping Sub-Surface Geology from Magnetic Data in the Hides area, Western Papuan Fold Belt, PNG

Kivior¹,

Markham²,

Mellon³

2016

ASEG Extended Abstracts

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SUMMARYHorizon mapping using magnetic data was conducted over a part of the Western Papuan Fold Belt, in an area of rugged terrain, where the geological structures are of relatively low complexity. Energy spectral analysis was used to detect magnetic susceptibility contrasts that were laterally merged to form magnetic interfaces corresponding to horizons derived from seismic and well data.Numerous magnetic interfaces were detected corresponding to: magnetic layers within the Darai Limestone, top of Ieru Formation, intra-Ieru and deeper intra-sedimentary boundaries. These mapped sedimentary surfaces form an anticlinal structure which plunges towards the south-east. A major thrust fault, mapped from magnetic data using automatic curve matching, truncates the anticline in the south-west. Sedimentary magnetic layers were mapped on both sides of this fault. The results obtained from the interpretation of the magnetic data are consistent with structures mapped from seismic and well data.

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Crustal Studies of South Australia Based on Energy Spectral Analysis of Regional Magnetic Data

Cited by 9 publications

References 11 publications

3-D seismic tomography of the Adelaide fold belt

3-D seismic tomography of the Adelaide fold belt

Magnetic constraints and susceptible inversions of Balapur Fault at central Kashmir Basin, NW Himalaya

Mapping Sub-Surface Geology from Magnetic Data in the Hides area, Western Papuan Fold Belt, PNG

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