From Wikipedia, the free encyclopedia
65 Ma Geologic provinces Shield Platform Orogen Basin Large igneous province Extended crust" src="http://upload.wikimedia.org/wikipedia/commons/thumb/a/a9/World_geologic_provinces.jpg/300px-World_geologic_provinces.jpg" class="thumbimage" border="0" height="159" width="300"> Oceanic crust 0-20 Ma 20-65 Ma >65 Ma Geologic provinces Shield Platform Orogen Basin Large igneous province Extended crust
Geology (from Greek: γη, ge, "earth"; and λόγος, logos, "knowledge") is the science and study of the solid matter that constitutes the Earth. Encompassing such things as rocks, soil, and gemstones, geology studies the composition, structure, physical properties, history, and the processes that shape Earth's components. It is one of the Earth sciences. Geologists have helped establish the age of the Earth at about 4.6 billion (4.6x109) years, and have determined that the Earth's lithosphere, which includes the crust, is fragmented into tectonic plates that move over a rheic upper mantle (asthenosphere) via processes that are collectively referred to as plate tectonics. Geologists help locate and manage the Earth's natural resources, such as petroleum and coal, as well as metals such as iron, copper, and uranium. Additional economic interests include gemstones and many minerals such as asbestos, perlite, mica, phosphates, zeolites, clay, pumice, quartz, and silica, as well as elements such as sulfur, chlorine, and helium.
Planetary geology (sometimes known as Astrogeology) refers to the application of geologic principles to other bodies of the solar system. However, specialised terms such as selenology (studies of the moon), areology (of Mars), etc., are also in use.
The word "geology" was first used by Jean-André Deluc in the year 1778 and introduced as a fixed term by Horace-Bénédict de Saussure in the year 1779. The science was not included in Encyclopedia Britannica's third edition completed in 1797, but had a lengthy entry in the fourth edition completed by 1809.[1] An older meaning of the word was first used by Richard de Bury to distinguish between earthly and theological jurisprudence.
