When the Compass Stopped Reversing Its Poles

  title={When the Compass Stopped Reversing Its Poles},
  author={Subir K. Banerjee},
  pages={1714 - 1715}
Earth9s geomagnetic field normally reverses a few times every million years, but during "superchron" periods, this switching process may stop for 30 to 50 million years. In his Perspective, Banerjee highlights the study by Tarduno et al., who have deduced the paleomagnetic field strength during the Cretaceous superchron from magnetite inclusions in lavas found in India. The results may provide clues to what causes the superchron periods. 

The paleomagnetism of single silicate crystals: Recording geomagnetic field strength during mixed polarity intervals, superchrons, and inner core growth

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


The bend in the Hawaiian-Emperor volcanic chain is an often-cited example of a change in plate motion with respect to a stationary hotspot. Growing evidence, however, suggests that the bend might

A Christian Physicist Examines the Age of the Earth

Electromagnetic fields as structure-function zeitgebers in biological systems: environmental orchestrations of morphogenesis and consciousness

Evidence of EM influence on cells and the integration of whole systems is described and it is suggested the growing literature of EM effects on biological systems has significant implications to the cell and its functional aggregates.

The Neurological Significance of Children‘s Drawing: The Scribble Hypothesis

Abstract Drawing is a substantive mental activity; its defense has been made. The Scribble Hypothesis extends the argument, establishing human mark-making as our defining language instinct. This

“Tied to the Land”: Climate Change Activism Among U.S. Hunters and Fishers

This paper investigates climate change activism among sportsmen and sportswomen, or hunters and fishers—a politically conservative group with historically deep roots to environmental conservation.

Part 3. Probability Estimates for the Features Required by Various Life Forms

The definition used here for a planet is broad enough to include a large satellite orbiting another planet and satellites in general and starless planets are not suitable candidates for life-support.



High Geomagnetic Intensity During the Mid-Cretaceous from Thellier Analyses of Single Plagioclase Crystals

Data from 56 Thellier-Thellier experiments on plagioclase crystals separated from basalts of the Rajmahal Traps of India suggest a time-averaged paleomagnetic dipole moment of 12.5 ± 1.4 × 1022 amperes per square meter, three times greater than mean Cenozoic and Early Cretaceous–Late Jurassic dipole moments when geomagnetic reversals were frequent.

The frequency of geomagnetic reversals and the symmetry of the nondipole field

The average frequency of geomagnetic reversals seen through a sliding window 10 m.y. long typically remains constant or nearly so for intervals of the order of 5 × 107 years and then increases or

Lengths of geomagnetic polarity intervals

Variations in the lengths of geomagnetic polarity, intervals are analyzed by means of a probability model based on the theory of Bernouli trials. Polarity reversals are assumed to occur as the result

Paleointensity of the Earth's Magnetic Field for the Past 400 Ma : Evidence for a Dipole Structure during the Mesozoic Low

Despite the limited number of paleointensity data available for the last 400 Ma, some general features of the magnetic field in the past can be drawn from their analysis. A mild selection applied to

Holocene paleointensities: Thellier Experiments on submarine basaltic glass from the East Pacific Rise

A complete description of the geomagnetic field requires both paleodirectional and paleointensity data. Although the paleointensity data base has grown steadily over the last three decades, it

The role of the Earth's mantle in controlling the frequency of geomagnetic reversals

A series of computer simulations of the Earth's dynamo illustrates how the thermal structure of the lowermost mantle might affect convection and magnetic-field generation in the fluid core. Eight

The intensity of the Earth's magnetic field over the past 160 million years

In contrast to our detailed knowledge of the directional behaviour of the Earth's magnetic field during geological and historical times,, data constraining the past intensity of the field remain

Long-term variations in palaeointensity

  • P. SelkinL. Tauxe
  • Environmental Science
    Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences
  • 2000
We compile a dataset of reliable palaeointensity estimates based both on published work and on new data from basaltic glass. The basaltic glass data more than double the number of reliable (Thellier