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| Detailed Reference Information |
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de Boer, C.B. and Dekkers, M.J. (1996). Grain-size dependence of the rock magnetic properties for a natural maghemite. Geophysical Research Letters 23: doi: 10.1029/96GL00781. issn: 0094-8276. |
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The natural maghemite from the Robe River mining district (Australia) is shown to be thermally very stable. The maghemite/hematite inversion occurs at ~650 ¿C for sized fractions (250 &mgr;m to <5 &mgr;m), enabling determination of Tc for maghemite at 610 ¿C. The maghemite is intimately intergrown with hematite and Js of the maghemite (corrected for the hematite content) is 64 Am2/kg. Jrs, Hcr and Hc range between 7.46--10.18 Am2/kg, 16.90--23.30 mT, and 6.38--9.00 mT respectively, indicating PSD maghemite with grain sizes between ~1 and ~20 &mgr;m. The grain-size dependence of the rock magnetic parameters of the maghemite is less prominent than those of magnetite of nominally the same size. It is suggested that the LT-behavior of ARM can be diagnostic of the presence of maghemite upon cooling to ~196 ¿C it shows no change; upon rewarming a gradual decrease in intensity occurs starting at ~-120 ¿C. ¿ American Geophysical Union 1996 The natural maghemite from the Robe River mining district (Australia) is shown to be thermally very stable. The maghemite/hematite inversion occurs at ~650 ¿C for sized fractions (250 &mgr;m to <5 &mgr;m), enabling determination of Tc for maghemite at 610 ¿C. The maghemite is intimately intergrown with hematite and Js of the maghemite (corrected for the hematite content) is 64 Am2/kg. Jrs, Hcr and Hc range between 7.46--10.18 Am2/kg, 16.90--23.30 mT, and 6.38--9.00 mT respectively, indicating PSD maghemite with grain sizes between ~1 and ~20 &mgr;m. The grain-size dependence of the rock magnetic parameters of the maghemite is less prominent than those of magnetite of nominally the same size. It is suggested that the LT-behavior of ARM can be diagnostic of the presence of maghemite upon cooling to ~196 ¿C it shows no change; upon rewarming a gradual decrease in intensity occurs starting at ~-120 ¿C. ¿ American Geophysical Union 1996 |
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Abstract |
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Experimental Methods |
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Sample Characteristics |
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Keywords
Geomagnetism and Paleomagnetism, Rock and mineral magnetism, Physical Properties of Rocks, Magnetic and electrical properties, Geomagnetism and Paleomagnetism, General or miscellaneous, Geomagnetism and Paleomagnetism, Instruments and techniques |
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Publisher
American Geophysical Union
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