isotopic examination

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• Crustal recycling — Understanding predictions of mantle dynamics helps geoscientists predict where subducted crust will end up. Crustal recycling is a tectonic process by which surface material from the lithosphere is recycled into the mantle during subduction. The… …   Wikipedia

• isotope — isotopic /uy seuh top ik/, adj. isotopically, adv. /uy seuh tohp /, n. Chem. any of two or more forms of a chemical element, having the same number of protons in the nucleus, or the same atomic number, but having different numbers of neutrons in… …   Universalium

• dating — I In geology and archaeology, the process of determining an object s or event s place within a chronological scheme. Scientists may use either relative dating, in which items are sequenced on the basis of stratigraphic clues (see stratigraphy) or …   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

• 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

• geology — /jee ol euh jee/, n., pl. geologies. 1. the science that deals with the dynamics and physical history of the earth, the rocks of which it is composed, and the physical, chemical, and biological changes that the earth has undergone or is… …   Universalium

• Kinetic isotope effect — The kinetic isotope effect (KIE) is the ratio of reaction rates of two different isotopically labeled molecules in a chemical reaction. It is also called isotope fractionation, although this term is somewhat broader in meaning. A KIE involving… …   Wikipedia

• Extraterrestrial materials — Most atoms on earth came from the interstellar dust and gas from which the sun and solar system formed. However, in the space science community extraterrestrial materials generally refers to objects now on earth that were solidified prior to… …   Wikipedia

• mass spectrometry — or mass spectroscopy Analytic technique by which chemical substances are identified by sorting gaseous ions by mass using electric and magnetic fields. A mass spectrometer uses electrical means to detect the sorted ions, while a mass spectrograph …   Universalium

• chemical element — Introduction also called  element,         any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed.       This article considers the… …   Universalium

• Age of the Earth — This article is about scientific estimates of the age of the Earth. For religious and other non scientific estimates, see Dating Creation. Earth as seen from Apollo 17 The age of the Earth is 4.54 billion years (4.54 × 109 years ± 1%) …   Wikipedia