Paleomagnetism can be used to date any geologic event that engenders the acquisition of remanent magnetization, including formation of igneous and sedimentary rocks, deposition of ore minerals, episodes of deformation, and other remagnetization processes.
study of the intensity and orientation of the earth's magnetic field as preserved in the magnetic orientation of certain minerals found in rocks formed throughout geologic time.
Dark areas denote periods where the polarity matches today's normal polarity; light areas denote periods where that polarity is reversed.
A geomagnetic reversal is a change in a planet's magnetic field such that the positions of magnetic north and magnetic south are interchanged, while geographic north and geographic south remain the same.
If the field were precisely that of a GAD then the north‐south direction and the latitude could be obtained accurately.
Geomagnetic polarity during the last 5 million years (Pliocene and Quaternary, late Cenozoic Era).
The results of stepwise heating experiments for a zircon from the Ahaggar region in the Sahara are compared to the geochronology determined by the rubidiumstrontium, uranium-thorium-lead, and potassium-argon dating methods.
A brief complete reversal, known as the Laschamp event, occurred only 41,000 years ago during the last glacial period.Paleomagnetism is the study of the Earth’s ancient magnetic field through the record of remanent magnetism preserved in rocks.The directions of remanent magnetization are used to deduce the position of the Earth’s magnetic pole relative to the study location at the time when this magnetization was acquired.The Earth's field has alternated between periods of normal polarity, in which the direction of the field was the same as the present direction, and reverse polarity, in which the field was the opposite. The time spans of chrons are randomly distributed with most being between 0.1 and 1 with an average of 450,000 years.Most reversals are estimated to take between 1,000 and 10,000 years.