To illustrate the potential of paleomagnetic dating in region and time interval with very large geomagnetic secular variation, we report paleomagnetic data from several sites in historical lava flows (1700–1900 AD) from the Antuco, Llaima and Villarrica volcanoes that permit to refine the ages of the major historical effusive volcanic events.
Reversals of the Earth's magnetic field reflect changes in the geodynamo—flow within the outer core—that generates the field.
The results confirm the high reliability of the global geomagnetic model C dated volcanic units in the time interval 1400–1750 AD indicate that more paleomagnetic results in well dated lava flows are necessary to improve the robustness of existing global geomagnetic models.
This is also true for Ceboruco lava flow, and overall mean directions and palaeointensities were then used for palaeomagnetic dating applying the Matlab tool and the global palaeosecular variation model SHA. For the 1870 lava flow, the dating resulted in an age ranging between 17 AD (95 per cent probability level), which includes the real emplacement age.The Earth's magnetic north pole can change in orientation (from north to south and south to north), and has many times over the millions of years that this planet has existed.The term that refers to changes in the Earth's magnetic field in the past is paleomagnetism.Investigations of the long term evolution of the past magnetic field are used to make inferences about the dynamics of the outer core and the geodynamo processes that produce the field.They also provide estimates of the long term variation in the magnetospheric shielding against solar wind and galactic cosmic rays.