Geomagnetic reversal rates following Palaeozoic superchrons have a fast restart mechanism

Mantle superplumes induce geomagnetic superchrons

We use polarity reversal systematics from numerical dynamos to quantify the hypothesis that the modulation of geomagnetic reversal frequency, including geomagnetic superchrons, results from changes in core heat flux related to growth and partial collapse of the two seismically-imaged lower mantle superplumes. We parameterize the reversal frequency sensitivity from numerical dynamos in terms of ...

External forcing of the geomagnetic +eld? Implications for the cosmic ray .ux—climate variability

Data on the relation of past climate variations and changes in the geomagnetic +eld can contribute to the research on a cosmic ray–climate link. This paper presents a synthesis of geological and astrophysical results about the link of magnetic +eld variations and Earth’s climate and external forcing. On millennial timescales, geomagnetic intensity lows are apparently in phase with times of low ...

Intrinsic paleointensity bias and the long-term history of the geodynamo

Many geodynamo models predict an inverse relationship between geomagnetic reversal frequency and field strength. However, most of the absolute paleointensity data, obtained predominantly by the Thellier method from bulk volcanic rocks, fail to confirm this relationship. Although low paleointensities are commonly observed during periods of high reversal rate (notably, in the late Jurassic), high...

Frequency of Proterozoic geomagnetic superchrons

The Paleomagnetism of Single Silicate Crystals: Recording Geomagnetic Field Strength during Mixed Polarity Intervals, Superchrons, and Inner Core Growth

[1] The basic features of the geomagnetic reversal chronology of the last 160 million years are well established. The relationship between this history and other features of the field, however, has been elusive. The determination of past field strength (paleointensity) is especially challenging. Commonly accepted results have come from analyses of bulk samples of lava. Historic lavas have been ...