ERSC 3P12 Lecture Notes - Lecture 12: Geochronology, Axial Precession, Top
29 May 2016
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Document Summary
Cyclostratigraphy, especially astrochronology, has revolutionized stratigraphy and geochronology in the past few decades. Astrochronology based on perturbations of the earth"s orbit around the sun, caused by original irregularities orbit plus gravitational influences from other planets in the solar system and those of the moon. Astrochronology has had fundamental impact on cenozoic timescale. Earth"s orbit and rotation around the sun follow newtonian physics. The earth"s orbit is not circular, and spin axis is not fixed (but wobbles). result is that: sun"s energy received by earth (albedo) varies predictably with time, distribution of heat around the earth (seasonality) also changes predictably with time. Realization of orbital forcing of earth"s climate came with understanding of ice ages: 1837 louis agassiz announced theory of great ice age. 1846 moved to usa, appointed professor of zoology and geology at harvard, founded. Agassiz born and raised in switzerland, son of a minister, studied in switzerland and germany. Developed interest in fossils (esp. fishes), and geology.
