The reversal is named after German physicist Johann Carl Friedrich Gauss and Japanese geophysicist Motonori Matuyama.
The Gauss–Matuyama reversal is a natural phenomenon that is frequently used as a boundary between the Pliocene and Pleistocene epochs,[1] marking the start of the Quaternary period, and is often used to date sediments.
The reversal is thought to have contributed to a hostile environment on Earth due to the lack of protective features of magnetic fields to shield life from ionizing radiation generated by the early Pleistocene supernova.
[2] The ionospheric ionization at the poles and equator reduces the energy on cosmic rays by several orders of magnitude.
During the reversal, the dipole field was reduced or entirely canceled because the virtual poles were located at low and intermediate latitudes, which would expose these regions to cosmic rays.