Kiaman Magnetic Interval in the Western United States

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Science  24 Feb 1967:
Vol. 155, Issue 3765, pp. 1012-1013
DOI: 10.1126/science.155.3765.1012


Late-Paleozoic red beds in the western United States indicate that Earth's magnetic field was reversed for a period of the order of 50 x 106 years. This finding agrees with similar results from igneous rocks in Australia, indicating, that the long period of reversal in the magnetic field was worldwide. The rocks on the two continents appear to be essentially equivalent in time, suggesting early magnetization of the red beds. The time spectrum of reversals is irregular in geologic time, but present evidence suggests reversals characterized by time scales of 104 or 105, 106, and 50 x 106 years. The 50 x 106 year period of steady reversed field is found in the late Paleozoic and is termed the Kiaman magnetic interval.