Secular variations of the geomagnetic field before, during, and after the excursion recorded in the Yangiyul section

The secular variation (SV) periods of the geomagnetic field, previously inf erred from the Yangiyul loess section of the Tashkent area, are reexamined. Based on thermoluminescence and paleomagnetic age estimates, the along-sec tion R-nst variations were compared with the worldwide data on the geomagne tic field intensity from 167 to 18 ka. The best correlation of the R-nst da ta was obtained for a 52-20-ka age estimate of the section. In order to add itionally verify this dating, we conducted a correlation analysis of the R- nst variation with time and the data on the 42-23-ka field intensity from H awaii lavas. As a result, we confirmed that the R-nst curve is not affected by lithology and climate changes and actually records the geomagnetic fiel d intensity. The SV periods were identified using the new spectral-time ana lysis, and the SV morphology, including the geomagnetic field intensity, an gular elements of the field, and magnetic susceptibility of rocks, was stud ied. This study showed that the periods of these SV characteristics are sim ilar and remain stable over the study time interval, including geomagnetic excursions.