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
Snowball Earth — The Snowball Earth hypothesis as it was originally proposedcite book author = Kirschvink, J.L. year = 1992 chapter = Late Proterozoic low latitude global glaciation: The snowball Earth title = The Proterozoic Biosphere: A Multidisciplinary Study… … Wikipedia
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
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
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
meteorite — 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] * * … Universalium
climate change — Introduction periodic modification of Earth s climate brought about as a result of changes in the atmosphere as well as interactions between the atmosphere and various other geologic, chemical, biological, and geographic factors within the Earth … Universalium
atmosphere, evolution of — Introduction the development of Earth s (Earth) atmosphere across geologic time. The process by which the current atmosphere arose from earlier conditions is complex; however, evidence related to the evolution of Earth s atmosphere, though… … Universalium
Pleistocene Epoch — Earlier and longer of the two epochs that constitute the Quaternary Period. The Pleistocene began с 1.8 million years ago and ended с 10,000 years ago. It was preceded by the Pliocene Epoch of the Tertiary Period and followed by the Holocene… … Universalium
Zinc — This article is about the metallic element. For other uses, see Zinc (disambiguation). copper ← zinc → gallium ↑ Zn ↓ Cd … Wikipedia
Yttrium — (pronEng|ˈɪtriəm) is a chemical element with symbol Y and atomic number 39. It is a silvery metallic transition metal chemically similar to the lanthanoids and has historically been classified as a rare earth element. Yttrium is almost always… … Wikipedia