You can download Encyclopedia of Geochemistry ebook here.
- Title: Encyclopedia of Geochemistry
- Author: William M. White
- Publisher: Springer
- Pages: 1574
Few fields within the earth sciences have grown as rapidly or had as great an impact as geochemistry. The impact of geochemistry has been vast and greatly influenced our understanding of virtually every aspect of this planet, its neighbors, and the life that makes it so unique.
Geochemistry is also revealing the workings of the Earth’s interior. Thermobarometers based on the distribution of elements between different minerals reveal the temperatures of metamorphism and crystallization in magma chambers. Combined with geochronometers, they can reveal the rates of these processes and the rates at which mountains rise and erode.
The 1960s James Bond film proclaimed that “Diamonds are Forever,” but it is zircon that holds the record for longevity. Because zircons concentrate uranium, they are natural clocks. Chemical and isotopic analysis of zircons reveals that creation of the continents began 4.4 billion years ago and proceeded subsequently in pulses that appear to correspond to times of supercontinent formation.
We have learned that geochemical cycles extend to the base of the mantle. Water, carbon, nitrogen, and sulfur are carried into the mantle at subduction zones. Isotopic analyses, among other approaches, reveal that these are then carried upward in mantle plumes, which seismic imaging show rise from the base of the mantle, and are released back to the surface by “hot spot” volcanoes such as Hawaii, Réunion, etc. These deep cycles operate much more slowly than surficial ones, as the discovery of the mass independently \ractionated isotopic signature of Archean atmospheric sulfur in lavas from volcanoes of French Polynesia demonstrates.