isotopic
101Tektite — Tektites (from Greek tektos , molten) are natural glass objects up to a few centimeters in size, which most scientists argue were formed by the impact of large meteorites on Earth s surface. Tektites are typically black or olive green, and their… …
102Earth 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… …
103Abiogenic petroleum origin — is a largely abandoned hypothesis that was proposed as an alternative to theory of biological petroleum origin. It was relatively popular in the past, but it went largely forgotten at the end of the 20th century after it failed to predict the… …
104Bioarchaeology — The term bioarchaeology was first coined by British archaeologist Grahame Clark in 1972 as a reference to zooarchaeology, or the study of animal bones from archaeological sites. Redefined in 1977 by Jane Buikstra, bioarchaeology in the US now… …
105Radiometric dating — (often called radioactive dating) is a technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.[1]… …
106Mass number — The mass number (A), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. Because protons and neutrons both are baryons, the mass number A is identical… …
107Isotopes of manganese — Naturally occurring manganese (Mn) is composed of 1 stable isotope; 55Mn. 25 radioisotopes have been characterized with the most stable being 53Mn with a half life of 3.7 million years, 54Mn with a half life of 312.3 days, and 52Mn with a half… …
108Donald J. DePaolo — is an American professor of geochemistry in the Department of Earth and Planetary Science at the University of California, Berkeley and Associate Laboratory Director for Energy and Environmental Sciences at the Lawrence Berkeley National… …
109Atomic ratio — The atomic ratio is a measure of the ratio of atoms of one kind (i) to another kind (j). A closely related concept is the atomic percent (or at.%), which gives the percentage of one kind of atom relative to the total number of atoms. The… …
110Atomic weight — (symbol: A sub|r) is a dimensionless physical quantity, the ratio of the average mass of atoms of an element (from a given source) to 1/12 of the mass of an atom of carbon 12.cite journal | author = International Union of Pure and Applied… …
