the isotopic composition of all elements
61Chemical element — The periodic table of the chemical elements A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus.[1] Familiar examples of …
62Pilbara craton — The Pilbara craton (the Pilbara province in northwest Western Australia), along with the Kaapvaal craton (the Kaapvaal province of South Africa) are the only remaining areas of pristine Archaean 3.6 2.7 Ga crust on Earth. Similarities of their… …
63Baltic Shield — The Baltic Shield (sometimes referred to as the Fennoscandian Shield) is located in Fennoscandia (Norway, Sweden and Finland), northwest Russia and under the Baltic Sea. The Baltic Shield is defined as the exposed Precambrian northwest segment of …
64Beaker culture — The Bell Beaker culture (sometimes shortened to Beaker culture, Beaker people, or Beaker folk; de. Glockenbecherkultur), ca. 2800 ndash; 1900 BC, is the term for a widely scattered cultural phenomenon of prehistoric western Europe starting in the …
65Emission spectrum — The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted by the element s atoms or the compound s molecules when they are returned to a lower energy state. Each element s …
66Copley Medal — The Copley Medal awarded to Mendeleev in 1905 …
67Criticality accident — …
68Oldest dated rocks — The oldest dated rocks on Earth, as an aggregate of minerals that have not been subsequently melted or disaggregated by erosion, are from the Archean Eon. Such rocks are exposed on the surface in very few places.[1] There is some controversy… …
69Earth 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… …
70meteorite — meteoritic /mee tee euh rit ik/, meteoritical, meteorital /mee tee euh ruyt l/, adj. /mee tee euh ruyt /, n. 1. a mass of stone or metal that has reached the earth from outer space; a fallen meteoroid. 2. a meteoroid. [1815 25; METEOR + ITE1] * * …
