Answers are grounded in this paper and cite their sources.
A first attempt to measure directly the magnetic polarity of submarine basalts dredged from the Reykjanes Ridge indicates that the first two magnetic anomalies over the ridge resulted from a reversal of the earth's magnetic field. Volcanic criteria were used to determine the orientation the samples had before they were dredged from the sea floor.
No takes yet. Share an insight, caveat, or question.
Boer et al. (1969) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: