Frequency Variation of the Earth's Obliquity and the Geomagnetic Intensity Cycles

Frequency modulation of the Earth's obliquity has provided an insight into the liquid core of the Earth that generates intensity cycles in the geomagnetic field. Calculations of the obliquity variations have reveled a series of frequency cycles which are almost identical with the spectral peaks from the composite curve of 33 records of relative paleointensity spanning the past 800 Kyr. A continuous record for the past 2 million years also reveals the presence of the major 100-Kyr periodicity in obliquity frequency and geomagnetic intensity. Thus the Earth's obliquity variation is a possible astronomical forcing mechanism, which drives the geomagnetic intensity cycles.