Oxidation and Magnetic Polarity in Single Icelandic Lavas and Dikes

• Published in: Geophysical Journal International
• Main Authors: Watkins, N. D., Haggerty, S. E.
• Format: Text
• Language: English
• Published: Oxford University Press 1968
• Subjects: Articles; Iceland
• Online Access: http://gji.oxfordjournals.org/cgi/content/short/15/3/305; https://doi.org/10.1111/j.1365-246X.1968.tb00187.x

The magnetic polarity and oxidation state have been measured in over five hundred and fifty specimens taken from traverses of fourteen lavas and seven dikes in Eastern Iceland. Oxidation is much higher and more variable in the lavas than in the dikes, suggesting that chemical analyses of dikes are to be preferred to those of lavas as being more representative of the parent magma. Oxidation spectra in each body, within-body polarity consistency, and data from baked sub-basaltic sediments all exclude the existence of self-reversals of magnetic polarity. The data as a whole show no correlation between polarity and oxidation state in the dikes, but a strong correlation exists between the percentage of reversed magnetic polarity specimens and higher oxidation in the lavas. No satisfactory explanation can be given for this observation. The correlation does not change significantly if previous independent oxidation classification systems are applied to the data. In the case of two high oxidation indices, a correlation exists between lava thickness and the oxidation state development.