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More on the alleged 1970 geomagnetic jerk More on the alleged 1970 geomagnetic jerk

French and United Kingdom workers have published reports describing a sudden change in the secular acceleration, called an impulse or a jerk, which took place around 1970. They claim that this change took place in a period of a year or two and that the sources of the alleged jerk are internal. An earlier paper by this author questioned their method of analysis pointing out that their...
Authors
L.R. Alldredge

The Steens Mountain (Oregon) geomagnetic polarity transition: 1. Directional history, duration of episodes, and rock magnetism The Steens Mountain (Oregon) geomagnetic polarity transition: 1. Directional history, duration of episodes, and rock magnetism

The thick sequence of Miocene lava flows exposed on Steens Mountain in southeastern Oregon is well known for containing a detailed record of a reversed‐to‐normal geomagnetic polarity transition. Paleomagnetic samples were obtained from the sequence for a combined study of the directional and intensity variations recorded; the paleointensity study is reported in a companion paper. This...
Authors
Edward A. Mankinen, M. Prevot, C. Sherman Gromme, Robert S. Coe

The Steens Mountain (Oregon) geomagnetic polarity transition, 2. Field intensity variations and discussion of reversal models The Steens Mountain (Oregon) geomagnetic polarity transition, 2. Field intensity variations and discussion of reversal models

We carried out an extensive paleointensity study of the 15.5±0.3 m.y. Miocene reversed‐to‐normal polarity transition recorded in lava flows from Steens Mountain (south central Oregon). One hundred eighty‐five samples from the collection whose paleodirectional study is reported by Mankinen et al. (this issue) were chosen for paleointensity investigations because of their low viscosity...
Authors
M. Prevot, Edward A. Mankinen, Robert S. Coe, C. Sherman Gromme
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