Category Archives: palaeomagic

Remagnetisation spoils the paleomagnetic party again

Did the Earth have a magnetic field before 3.5 billion years ago? Previous paleomagnetic studies of the world’s oldest mineral grains – the Jack Hills zircons, which have maximum ages of 4.4 billion years – claimed that tiny inclusions of … Continue reading

Categories: Archean, deep time, palaeomagic, paper reviews

How long was the last magnetic reversal – and why might subducting slabs have had a say in what it looked like?

A new paper on the chronology of the last magnetic reversal concludes it took 20,000 yrs, and there were two distinct excursions – where the field becomes weak and disorganized, but it recovers without reversing polarity – before the main event about … Continue reading

Categories: geology, palaeomagic, paper reviews, rocks & minerals

A very slow magnetic doom

Why an ‘imminent’ reversal of the Earth’s magnetic field doesn’t mean what most people think it means. Continue reading

Categories: deep time, geology, palaeomagic, public science, society

Reconstructing ocean spreading when half your record is now in the mantle (or: a plug for my new paper)

If you’re studying the last 100 million years or so of plate tectonics, the history of sea-floor spreading recorded by the magnetic stripes that parallel and extend away from the Earth’s ocean ridges is a key source of information. Each … Continue reading

Categories: geology, geophysics, palaeomagic, tectonics

Scenic Saturday: our stripy oceans, explained 50 years ago today!

A slightly different Scenic Saturday this weekend, as we celebrate an important milestone in geological science: a look at the South Pacific through a geophysical lens. The colours on this map show fluctuations in the Earth’s magnetic field produced by … Continue reading

Categories: geology, palaeomagic, tectonics