Permian Secular Variation of the Ayaguz formation in Kazakhstan

Abstract

This study uses 60 individual volcanic flows from the Early Permian in eastern Kazakhstan with the intention of analyzing to what extent secular variation of the geomagnetic field may be reduced during the Kiaman (Permo-Carboniferous) Reversed Polarity Superchron (KRPS). Such a study can be important because the confirmation of a relationship between secular variation and polarity reversal frequency during the Permian would allow for the use of paleosecular variation (PSV) data to infer the dynamo stability in the past, something that is currently not possible for times earlier than 160 Ma. The samples analyzed for the study were collected from a thick pile in the Chingiz Range of NE Kazakhstan with a U/Pb age of 283±2.4 Ma. The resulting data were compared to the data obtained by Dr. Bazhenov, who collected samples from the same volcanic pile for a parallel investigation. Nearly all of the paleomagnetic directions obtained in thermal demagnetization are seen to be SW and up, with a mean paleopole position at longitude (331.4E), and south-latitude (-37.9) confirming the expected mean Permian pole position. The resulting data also matched the anticipated high precision parameter (49.4), indicative of a stable geodynamo. This study therefore validates the correlation between secular variation and polarity reversal frequency.