Geomagnetic excursions of the Brunhes chron and global climate oscillations

The paper analyzes data on geomagnetic excursions of the Brunhes chron and on their relation to global climate variations. According to the geomagneti c field behavior and their duration, excursions are subdivided into short o nes (about 10(2) to 10(3) years long), with a partial field reversal, and l ong ones (about 10(4) years), with a complete field reversal. It is experim entally established that excursions took place in various climatic environm ents; however, regardless of their age and type, excursions started and end ed in glaciation periods. Comparison between the excursion time scale of th e Brunhes chron and the solar radiation curve based on the theory of M. Mil ankovich showed that the excursions coincided in time with solar radiation maximums. A distinct correlation between the geomagnetic intensity variatio n and climate changes, as constrained by the palynological data, was establ ished from one of the sections studied. A similar correlation is recognized between the paleointensity recorded in deep-sea sediment cores of the equa torial Pacific and oxygen-isotope stages. Disputable aspects of the relatio nship between variations in the geomagnetic field and global climatic chang es are discussed. A hypothesis on the general mechanism responsible for the se variations is proposed.