Magnetic petrophysical results from the Hamersley Basin and their implications for interpretation of magnetic surveys

Guo, Wenqiang; Li, Zheng‐Xiang; Dentith, Mike

doi:10.1080/08120099.2011.552984

Cited by 8 publications

(6 citation statements)

References 17 publications

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“…This reinforces the hypothesis that Natural Remanent Magnetization (NRM) cannot be neglected when dealing with crustal magnetization. Additionally, the increase of thickness should be taken into account in the case of metamorphic belts, as multiple geological observations of folded BIFs (or slices of BIF) have been done on different areas (Alexandrov, 1973;Ravat et al, 1993;Schmidt et al, 2007;Guo et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Iron Formations as the Source of the West African Magnetic Crustal Anomaly

et al. 2018

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The geological sources of major magnetic field anomalies are still poorly constrained, in terms of nature, geometry, and vertical position. A common feature of several anomalies is their spatial correlation with cratonic shields and, for the largest anomalies, with Banded Iron Formations (BIF). This study first unveils the magnetic properties of some BIF samples from Mauritania, where the main part of the West African magnetic anomaly is observed. It shows how strong the magnetic susceptibility and natural remanent magnetization for such rocks are. High Koenigsberger ratios imply that the remanent magnetization should be taken into account to explain the anomaly. A numerical modeling of the crust beneath this anomaly is performed using these constraints and both gravity and magnetic field data. A forward approach is used, investigating the depth, thickness and magnetization intensity of all possible crustal lithologies. Our results show that BIF slices can be the only magnetized crustal sources needed to explain the anomaly, and that they could be buried several kilometers deep. The results of this study provide a new perspective to address the investigation of magnetic field anomaly sources in other cratonic regions with BIF outcrops.

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Section: Introductionmentioning

confidence: 99%

Iron Formations as the Source of the West African Magnetic Crustal Anomaly

et al. 2018

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“…Magnetic susceptibility of natural rocks and ores plays important roles either directly or indirectly in many applications, such as oil and mineral explorations [1]- [3], geology [4], climate change and environment assessment [5] [6], mining and metallurgy [7] [8], and archeology [9]. However, magnetic susceptibility of many types of rocks and ores is not isotropic, i.e., the magnitude of magnetic susceptibility of some rocks and ores varies with the orientation of the rocks and ores with respect to the measurement of magnetic susceptibility.…”

Section: Introductionmentioning

confidence: 99%

Mathematical Model of Anisotropy of Magnetic Susceptibility (AMS)

Guo¹

2015

JAMP

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Magnetic susceptibility of natural rocks and ores is important in many applications. In a few rock types magnetic susceptibility is independent of the direction in which a weak magnetic field is applied. Such rocks are magnetically isotropic. In most rock types, however, the magnitude of magnetic susceptibility in a constant weak field depends on the orientation of the magnetic field applied. Such rocks are magnetically anisotropic and such directional variation in magnetic susceptibility with these rocks is termed as anisotropy of magnetic susceptibility (AMS). Although attempts have been made on describing AMS using mathematical models, there is still a need to present a more consistent and united mathematical process for AMS. This paper presents a united AMS model by rationalizing the existing pieces of different AMS models through a consistent approach. A few examples of AMS from some types of natural rocks and ores are also presented to substantiate this united AMS model.

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“…Petrophysical properties used for the Ashburton and Bresnahan Basins were derived from this project (Uren et al 2016). The Hamersley and Fortescue Group magnetic properties for induced and remanent magnetisation were derived from Guo et al (2011) and the density values from Guo (1999). Pilbara Craton granite magnetic susceptibility values were derived from Wellman, (1999) and Gascoyne Provence granitoid magnetic susceptibility and density values were derived from Aitken et al (2014).…”

Section: The Interpretations Inmentioning

confidence: 99%

An integrated approach to mapping crustal geology and structures in the NE Capricorn Orogen, Western Australia: Implications for uranium exploration

Uren

Aitken

Occhipinti

et al. 2018

ASEG Extended Abstracts

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SUMMARYGeological, geophysical and remote sensing data have been used in the northweast Capricorn Orogen to map crustal scale structures beneath Paleoproterozoic Basins that may have focused mineralising fluids. The interpretations were largely based on upwardly continued bouguer gravity and magnetic data, then tested using petrophysically constrained forward modelling techniques. The most likely interpretation for deep crustal component of the region was found to be the Bandee Seismic Provence modelled with a mafic petrophysical character. A small portion of the study area in the northern part of the study area was modelled as an extension of the Pilbara Craton with overlying Hamersley-Fortescue Groups. Various gravity lows observed in the data were tested to determine if they represented a sub-basin, granitoid intrusion or shallow batholith. The gravity lows were found to be most likely related to granitoid intrusions. One significant deep-crustal scale structure in the central-southern part of the study area can be related to a fault mapped at surface and from Landsat 8 data. The structure has had limited exploration along its extent. The integrated approached of mapping, including surface geological mapping, indicates potential carbonaceous sediments in the hangingwall of the southern major fault zone could be prospective for uranium and gold-silver mineralisation. The friable nature of the coarse grained sandstone of the Bresnahan Group, that un-conformably overlies the carbonaceous mudstone, indicates fluid flow interaction with the unconformity could have occurred which enhances the prospectivity for uranium.

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Magnetic petrophysical results from the Hamersley Basin and their implications for interpretation of magnetic surveys

Cited by 8 publications

References 17 publications

Iron Formations as the Source of the West African Magnetic Crustal Anomaly

Iron Formations as the Source of the West African Magnetic Crustal Anomaly

Mathematical Model of Anisotropy of Magnetic Susceptibility (AMS)

An integrated approach to mapping crustal geology and structures in the NE Capricorn Orogen, Western Australia: Implications for uranium exploration

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