Earth's Paleomagnetic Field and its Changes Through Time.

Paleomagnetism is the only way to access the behavior of the geomagnetic field of internal origin through geological time. Therefore, the complete description of the paleosecular variation (PSV) is fundamental for unraveling the evolution of the Earth's core. Modeling of PSV relies on observing the fluctuations in the direction and intensity of the field on the surface, the evaluation of the paleomagnetic data dispersion in different times and situations of low and high reversal rates, the kinematics of the virtual poles during reversals, and other aspects. Magneto-cyclostratigraphy is a powerful tool to constrain the age of sedimentary formations, and the recognition of patterns of magnetic variation represents a breakthrough in the development of cyclostratigraphy. This paper reviews some of the contributions to the subject of the Laboratory of Paleomagnetism at Instituto de Astronomia, Geofísica e Ciências Atmosféricas the University of São Paulo.