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Investigations of Some Magnetic and Mineralogical Properties of the Laschamp and Olby Flows, France

Published online by Cambridge University Press:  20 January 2017

John Whitney ,
H. P. Johnson ,
Shaul Levi  and
Bernard W. Evans
John Whitney
Affiliation:
Geophysics Program, AK-50, University of Washington, Seattle, WA 98195
H. P. Johnson
Affiliation:
Geophysics Program, AK-50, University of Washington, Seattle, WA 98195
Shaul Levi
Affiliation:
Geophysics Program, AK-50, University of Washington, Seattle, WA 98195
Bernard W. Evans
Affiliation:
Department of Geological Sciences, AK-20, University of Washington, Seattle, WA 98195
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Abstract

Rock-magnetic, paleomagnetic and petrologic properties of samples from the Laschamp and Olby basalt formations in France were studied to aid in determining the validity of the Laschamp geomagnetic field reversal reported by Bonhommet and Babkine. The Laschamp flow contains ilmenomagnetite, with partial alteration of the magnetite to hematite. Ilmenomagnetite in the Olby flow has largely recrystallized at high temperatures to a composite mozaic intergrowth of pseudobrookite, titanohematite and magnesioferrite, with rare residual magnetite and lamellae of ilmenite. The remanent magnetization is stable and resides primarily in single-domain magnetite particles. Our results indicate that the magnetizations of the Laschamp and Olby flows faithfully record the direction of the ambient magnetic field in which they cooled.

Type
Original Articles
Information
Quaternary Research , Volume 1 , Issue 4 , December 1971 , pp. 511 - 521
Copyright
University of Washington

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