Cooling Following the Magnetic Field Weakening During the Matuyama–Brunhes Transition Recorded by Paks Loess, Hungary

Detailed paleomagnetic and rock magnetic investigations of the Paks loess (Hungary) were conducted to determine the stratigraphic position of the Matuyama–Brunhes Transition (MBT) and to attempt to reveal the sign of any possible influences of geomagnetic field change on the climate during the geomagnetic polarity reversal. Progressive thermal and alternating field demagnetizations of samples showed that the reverse polarity field begins to fluctuate in a stratigraphic position of the well-developed, so-called Paks Double 2 (PD2) paleosol (formed in Marine Isotope Stage 19, MIS19), and continues up to the middle-to-upper part of the overlying paleosol-to-loess transition layer (MIS19 to 18). Considering the relative paleointensity variation from Paks, this is consistent with various global records. Along with the weakening of the geomagnetic field, changes in environmental proxies were also recognized. Magnetic proxies indicate cooling during the MIS19 interglacial period. Theoretically, it may be connected to the weakening of the geomagnetic field. Still, there are alternatives to be considered, which may form the same features thought to be the result of the Umbrella effect.