geochemical barrier

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• sedimentary rock — Rock formed at or near the Earth s surface by the accumulation and lithification of fragments of preexisting rocks or by precipitation from solution at normal surface temperatures. Sedimentary rocks can be formed only where sediments are… …   Universalium

• Earth Sciences — ▪ 2009 Introduction Geology and Geochemistry       The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… …   Universalium

• Aluminium foil — (known as aluminum foil in North America) is aluminium prepared in thin sheets with a thickness less than 0.2 mm / 0.008 in, although much thinner gauges down to 0.006 mm are commonly used. [http://www.alufoil.org/eng/alufoil 343.html European… …   Wikipedia

• climate — /kluy mit/, n. 1. the composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years. 2. a region or… …   Universalium

• Life Sciences — ▪ 2009 Introduction Zoology       In 2008 several zoological studies provided new insights into how species life history traits (such as the timing of reproduction or the length of life of adult individuals) are derived in part as responses to… …   Universalium

• Cosmic ray — For the film, see Cosmic Ray (film). Cosmic radiation redirects here. For some background types of cosmic radiation, see cosmic background radiation and cosmic background. The energy spectrum for cosmic rays Cosmic rays are energetic charged… …   Wikipedia

• Mantle plume — A superplume generated by cooling processes in the mantle.[1] A mantle plume is a hypothetical thermal diapir of abnormally hot rock that nucleates at the core mantle boundary and rises through the Earth s mantle. Such plumes were invoked in 1971 …   Wikipedia

• Silurian Period — Interval of geologic time, 443–417 million years ago. The third period of the Paleozoic Era, the Silurian follows the Ordovician Period and precedes the Devonian. It marks the first appearance of land plants and jawed fishes. The continents were… …   Universalium

• Coral — For other uses, see Coral (disambiguation). Coral Pillar coral, Dendrogyra cylindricus Scientific classification Kingdom …   Wikipedia

• Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics       Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity.       Computer scientist Manindra Agrawal of the… …   Universalium

• petroleum — petroleous, adj. /peuh troh lee euhm/, n. an oily, thick, flammable, usually dark colored liquid that is a form of bitumen or a mixture of various hydrocarbons, occurring naturally in various parts of the world and commonly obtained by drilling:… …   Universalium