Long-term variations in the flux of cosmogenic isotope 10Be over the last 10000 years: Variations in the geomagnetic field and climate

A spectral analysis of data on the flux of cosmogenic ¹⁰Be in ice core samples from the Central Greenland (project GRIP) over the last 10 thousand years have been carried out. It has been shown that the ¹⁰Be flux varies cyclically; the most significant cycle is of about 2300 years. Variations in the position of the virtual geomagnetic pole over 8000 years have been analyzed. Significant components, pointing to the cyclic variation in the position of the geomagnetic pole with a period of about 2300 years, have been revealed in a periodogram of the virtual geomagnetic pole longitude. In addition to the nearly 2300-year-long cycle, some lines are observable in the ¹⁰Be flux periodogram, which can be considered as a manifestation of the 1000-year-long cycle of the ¹⁰Be deposition rate on the ice surface. The relationship between the cyclicity of the geomagnetic pole position and the ¹⁰Be flux is discussed.