Natural remanence, initial susceptibility, saturation magnetization and strong field thermal properties have been measured on 45 basalt cores representing two vertical sections through the flow separated horizontally by 16 m. The form and magnitude of the profiles for every magnetic property differ in the two sections, which means that lateral variations are quite comparable to vertical variations in this lava. Stability of remanence, as determined by a.c. partial demagnetization, is found to be related to two opaque petrological properties. High stability is associated either with titanomagnetite high-temperature oxidation (ilmenite exsolution etc.) or with titanomagnetite granulation. Granulation consists of areas of titanomagnetite replaced by fine aggregates of rutile and is described in detail in Part I of this paper. A relationship exists between strong field heating curves and natural titanomagnetite high-temperature oxidation. The Curie point spectrum has two isolated peaks. As natural oxidation increases the relative intensity of the high Curie point component increases. The possibility of titanomagnetite granulation, believed to be formed several million years after lava eruption, causing remagnetization is discussed and rejected.
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Ade‐Hall et al. (1968) studied this question.
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