Some outstanding assumptions in geophysical studies of the Earth | ||
| NRIAG Journal of Astronomy and Geophysics | ||
| Volume 4, Issue 1, June 2015, Pages 130-133 PDF (512.54 K) | ||
| DOI: 10.1016/j.nrjag.2015.06.003 | ||
| Author | ||
| Maroof A. Hegazy | ||
| Abstract | ||
| Three examples of incorrect or incomplete assumptions are considered. (1) The oceanic geothermal gradient was originally established using an assumed temperature at the boundary between the rigid lithospheric tectonic plate and the underlying plastically deforming asthenospheric mantle. Revising this invalid temperature assumption has major implications for the concentration of radio-active elements within the mantle, convective patterns and the rate of cooling of the Earth, etc. (2) The earliest 19th century spectral observations of the surface of the Sun identified meteoritic components. This was plausible as Sunspots were thought to be meteoritic impacts, but are now known to be of internal origin. The Sun has no meteoritic materials and its age and origin require major revision. (3) Astronomical changes in the position of objects in the solar system provide causative mechanisms for periodicities in many Earth processes – climate, sea-level, sea-floor spreading, volcanism, etc. Unexplained spectral features probably originate from effects due to the same bodies influencing the solar processes that then affect the magnitude and nature of solar radiation, solar wind, electromagnetic storms, etc., reaching the Earth’s upper atmosphere. | ||
| Keywords | ||
| Plate tectonic mechanism; Geothermal Gradient; Solar composition; Age of Sun; Milankovitch cycles; Solar variability | ||
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