Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4688858 | Journal of Geodynamics | 2006 | 7 Pages |
Abstract
Fossils and tidal deposits as well as the possibility to compute values of the lunar tidal torque for different geological epochs allow us to model the variations in time of the Earth's figure, assuming that the latter remains, on a global scale, close to a hydrostatic equilibrium figure. On this basis, one can infer the variations of the Earth's most important geodynamic parameters over much of the geological past. Thus, the geometrical flattening has decreased from 5Â ÃÂ 10â3 to 3Â ÃÂ 10â3, the normal gravity on annual average increase at the equator by â¼2 nanogal. In present study, first the influence of the tidal friction on the length of day (LOD), geometrical flattening and the Earth-Moon distance during the history of the Earth will be discussed. The different despinning rates during the Phanerozoic (Pz: 0-0.56Â Ga BP) and Proterozoic (Ptz: 0.56-2.5Â Ga BP) will be also demonstrated. For understanding the development of the dynamics of the early Earth and the Earth-Moon system the length of day during Katarchean (3.00-4.55Â Ga BP) shortly after the Earth formation was also estimated.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth-Surface Processes
Authors
P. Varga,