“Concrete” Testimony to Milankovitch Cycle in Earth's changing obliquity



The present-day obliquity of the ecliptic of the Earth is ϵ = 23°26′ 22″ and is decreasing by about 0″.5 a year. This article reports a “concrete” terrestrial testimony to this time variation, which plays a major part in the Milankovitch cycles.

The obliquity is the angle between the equatorial plane, which is determined by Earth's rotation, and the ecliptic plane, defined as Earth's orbital plane around the Sun. It gives rise to the seasons; the two parallels of latitudee, the Tropic of Cancer in the Northern Hemisphere and the Tropic of Capricorn in the Southern Hemisphere, mark the limits of highest latitudes that the subsolar point reaches at solstices each year.