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Late acquisition of “primary” remanence in some fresh basalts: A cause of spurious paleomagnetic results
Author(s) -
Hoffman Kenneth A.
Publication year - 1984
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl011i008p00681
Subject(s) - paleomagnetism , remanence , thermoremanent magnetization , basalt , geology , rock magnetism , curie temperature , magnetization , mineralogy , natural remanent magnetization , geochemistry , geophysics , condensed matter physics , magnetic field , physics , quantum mechanics , ferromagnetism
Although rarely reported, the principal magnetic carrier associated with rocks of basaltic composition can be titanomagnetite (Fe 3−x Ti x O 4 ) very rich in titanium (x>.75). If not oxidized during cooling, such a pristine magnetic carrier will possess a Curie temperature too low to insure the acquisition of a stable thermoremanent magnetization (TRM). A stable chemical remanent magnetization (CRM) ultimately may be acquired through room temperature oxidation of the titanomagnetite to titanomaghemite; however, such a process can occur during a time interval far removed from that of initial cooling. A case study is presented which dramatically illustrates the spurious nature of paleomagnetic results associated with such an occurrence.