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Conference paperAbubakar R, Muxworthy AR, Sephton M, et al., 2016,
Mapping Petroleum Migration Pathways in Wessex Basin Using Magnetics and Seismic Mapping (poster)
, Magnetic Interactions 2016 -
Conference paperMaidment S, Muxworthy AR, 2016,
A chronostratigraphic framework for the Morrison formation, western USA: A sequence stratigraphic and magnetostratigraphic approach (poster)
, Magnetic Interactions 2016 -
Conference paperMuxworthy AR, 2016,
How Well Does Preisach Theory Predict Pseudo-Single-Domain Behavior? (poster)
, Magnetic Interactions 2016 -
Conference paperValdez-Grijalva MA, Muxworthy AR, 2016,
Simulated 'early onset' PSD behaviour: Size and shape effects in non-interacting greigite nanoparticles
, Magnetic Interactions 2016 -
Conference paperAlmeida T, Muxworthy AR, Kasama T, et al., 2016,
Effect of maghemization on the magnetic properties of non-stoichiometric pseudo-single-domain magnetite particles (poster)
, Magnetic Interactions 2016 -
Conference paperShah J, Muxworthy AR, Almeida TP, et al., 2016,
In-situ heating holography of chondrule dusty olivine
, Magnetic Interactions -
Conference paperBadejo, Muxworthy AR, Fraser A, 2016,
Application of magnetic techniques to lateral hydrocarbon migration - Lower Tertiary reservoir systems, UK North Sea (poster)
, Magnetic Interactions 2016 -
Conference paperAlmeida T, Muxworthy AR, Kasama T, et al., 2015,
Direct visualisation of CRM and TRM of pseudo-single-domain magnetite grains and the implications for reliable palaeomagnetic signal acquisition (invited)
, AGU Fall 2015 -
Conference paperAlmeida T, Muxworthy AR, Kasama T, et al., 2015,
Effect of maghemization on the magnetic properties of non-stoichiometric pseudo-single-domain magnetite particles (poster)
, AGU Fall 2015 -
Conference paperDi Chiara A, Muxworthy AR, Trindade R, 2015,
Paleointensity of Proterozoic magmatic rocks from South America, preliminary results
, CRES 2015 -
Conference paperShah J, Muxworthy AR, Almeida T, et al., 2015,
Electron Holography of Chondrule Dusty Olivine (poster)
, Meteorites and Solar System formation workshop -
Journal articleBerndt T, Muxworthy AR, Paterson GA, 2015,
Determining the magnetic attempt time τ0, its temperature dependence and the grain-size distribution from magnetic viscosity measurements
, Journal of Geophysical Research. Solid Earth, Vol: 120, Pages: 7322-7336, ISSN: 2169-9313A new method to determine the atomic attempt time τ0 of magnetic relaxation of fine particles, which is central to rock and soil magnetism and paleomagnetic recording theory, is presented, including the determination of its temperature dependence, and simultaneously the grain-size distribution of a sample. It is based on measuring a series of zero-field magnetic viscous decay curves for saturation isothermal remanent magnetization at various different temperatures, that are later joined together on a single grain-size scale from which the grain-size distribution and attempt time are determined. The attempt time was determined for three samples containing non-interacting, single-domain titanomagnetites of different grain-sizes for temperatures between 27 K and 374 K. No clear temperature-dependent trend was found, however, values varied significantly from one sample to the other: from 10⁻¹¹ s to 10⁻⁸ s; in particular, the sample containing multiple magnetic phases had an effective attempt time significantly lower than the more homogeneous samples, thereby questioning the applicability of the simple Néel-Arhennius equation for magnetic relaxation for composite materials.
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Journal articleAlmeida TP, Muxworthy AR, Kovács A, et al., 2015,
Visualisation of high temperature magnetisation states in magnetite grains using off-axis electron holography
, Journal of Physics: Conference Series, ISSN: 1742-6588 -
Journal articleAbubakar R, Muxworthy AR, Southern P, et al., 2015,
Formation of magnetic minerals in hydrocarbon-generation conditions
, Marine and Petroleum Geology, ISSN: 1873-4073In this paper, we report the pyrolysis and formation of magnetic minerals in three source rock samples from the Wessex Basin in Dorset, southern England. The experimental conditions in the laboratory recreated the catagenesis environment of oil source rocks. Magnetic analysis of both the heated and the unheated samples at room temperature and at very low temperatures (5 K), coupled with transmission electron-microscopy imaging and X-ray analysis, revealed the formation of nanometre-sized (<10 nm), magnetic particles that varied across the rock samples analysed, but more importantly across the pyrolysis temperature range. Magnetic measurements demonstrated the formation of these magnetic minerals peaked at 250 °C for all rock samples and then decreased at 300 °C before rising again at 320 °C. The newly formed magnetic minerals are suggested to be primarily pyrrhotite, though magnetite and greigite are also thought to be present. The sizes of the magnetic minerals formed suggest a propensity to migrate together with oil potentially explaining the magnetic anomalies observed above and within oil fields.
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Conference paperMuxworthy AR, 2015,
How well does Preisach Theory predict Pseudo-Single-Domain Behavior? (poster)
, AGU Fall 2015
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