Gauss-Matuyama polarity transition

Abstract

The Gauss-Matuyama (G-M) polarity transition has been identified in a 9 cm rotary-drilled core from Scaries Valley, California. The lithology, recovery and preservation of the sediments allow a detailed investigation of the transition. The transition is estimated to have lasted approximately 2000 years. About 2000 years earlier, a short reversal also occurred that lasted 2000 years. The relative field intensity decreased by at least 70 % both during this short reversal and the G-M transition. The virtual geomagnetic poles path for the G-M transition is restricted to a meridional band 20° wide in the Atlantic Ocean and closely matches the v.g.p. path for the Matuyama-Brunhes transition recorded at Lake Tecopa, California. On the other hand, the pole path for the G-M transition recorded in Russia (about 180° in longitude from Searles Valley) is nearly antipodal at low latitudes to the Learies Valley pole path. These data indicate that the transition field associated with the reversal was dominated by non-dipole components.