Results 211 to 220 of about 9,373 (256)

Magnetization of the oceanic crust: Thermoremanent magnetization of chemical remanent magnetization?

Journal of Geophysical Research: Solid Earth, 1987
We propose a model in which chemical remanent magnetization (CRM) acquired within the first 20 m.y. of crustal evolution may account for 80% of the bulk natural remanent magnetization of older basalts. The CRM of the crust is acquired as the original thermoremanent magnetization (TRM) is lost through low‐temperature alteration.
C. A. Raymond, J. L. LaBrecque
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Thermo-chemical Remanent Magnetization of Rocks

Nature, 1963
WHEN titanomagnetites, xFe2TiO4·(1-x)Fe3O4, are heated in the atmosphere at a certain high temperature, they are oxidized, becoming solid solutions of titanomagnetites and titanomaghaemites, yFeTiO3·(l-y)Fe2O3 having a spinal crystal structure1–4.
TAKESI NAGATA, KAZUO KOBAYASHI
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Anomalous magnetic directions recorded by laboratory-induced chemical remanent magnetization

Nature, 1981
It has been generally accepted that chemical remanent magnetization (CRM) is acquired either in the direction of the ambient field at the time of chemical alteration1 or in the direction of a pre-existing natural remanent magnetization (CRM) 2–4. We report here our experiments in which CRM is carried by magnetite formed during laboratory heating of ...
Monika E. Bailey, Christopher J. Hale
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Chemical remanent magnetization in synthetic magnetite

Journal of Geophysical Research: Solid Earth, 1991
As a magnetic grain produced by a chemical process below its blocking temperature grows through a critical volume in the presence of a magnetic field, its moment becomes blocked and it acquires a chemical remanent magnetization, CRM. Despite its importance to paleomagnetism, the properties of CRM and the controls on its behavior are still poorly ...
Thomas Pick, Lisa Tauxe
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Imprinting chemical remanent magnetization in claystones at 95 °C

Earth and Planetary Science Letters, 2008
Abstract Thermal effects related to burial and hydrothermal alteration leads to chemical remanent magnetization (CRM). We present an experimental study of CRM production by heating claystones at 95 °C. A vertical magnetic field of 2 mT was applied to the claystones during heating and the evolution of the remanence during heating in air is monitored ...
C. Aubourg, J.P. Pozzi, D. Janots, L. Sahraoui   +3 more
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Acquisition of chemical remanent magnetization by synthetic iron oxide

Nature, 1987
A fundamental assumption of palaeomagnetism is that rocks can provide a reliable record of the Earth's magnetic field. It is known that as magnetic minerals undergo chemical change they acquire a form of chemical remanent magnetization (CRM)1. Indeed, the magnetic phases formed at different times in the history of the rock may add several components of
Laura B. Stokking, Lisa Tauxe
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Magnetic properties of chemical remanent magnetization in synthetic and natural goethite: Prospects for a natural remanent magnetization/thermoremenant magnetization ratio paleomagnetic stability test?

Journal of Geophysical Research: Solid Earth, 1992
Goethite was synthesized under controlled field conditions (horizontally directed field of 0.30 mT) at 30° and 55°C with and without the presence of microfiber glass filters. Upon goethite aging from freshly precipitated ferrihydrite an inverse fabric of the magnetic susceptibility develops, more prominently for the 55°C than for the 30°C synthesis ...
Mark J. Dekkers, Pierre Rochette
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Experimental study of chemical and crystallization remanent magnetizations in magnetite

Physics of the Earth and Planetary Interiors, 1987
Abstract Crystallization magnetization (KRM) of magnetite is experimentally studied by the oxidation of fine grains of pyrite and by the oxidation (unmixing) of titanomagnetite with Tc = 150–200°C at the temperature of 400–450°C in the magnetic field of 50–100 mkT.
T.K.T. Nguyen, D.M. Pechersky
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Two types of chemical remanent magnetization during the oxidation of magnetite

Physics of the Earth and Planetary Interiors, 1987
Abstract The chemical remanent magnetization (CRM), M CRM , resulting from oxidation of equidimensional magnetite to a mixture of 90% hematite and 10% cation-deficient magnetite is jointly controlled by the initial anhysteretic remanent magnetization, ( M ARM ), of the parent magnetite and the field H CRM applied during oxidation.
Franz Heider, David J. Dunlop
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Self-reversal of chemical remanent magnetization during multiphase oxidation of synthetic titanomagnetites

Russian Journal of Earth Sciences, 2008
[1] The possibility of self-reversal of chemical remanent magnetization (CRM) is studied on synthetic samples of titanomagnetites (Fe3−xTixO4, where x = 0.2, 0.4, and 0.6) that experienced multiphase oxidation in air at 500◦C in the presence of the constant magnetic field H = 0.1 mT.
A. K. Gapeev, S. K. Gribov
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