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Geology
Geology (from Greek: ge, "earth"; and logos, "knowledge") is the science and
study of the solid matter that constitute 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.
The work Peri lithon (On Stones) by Theophrastus (372-287 BC), a student of
Aristotle, remained authoritative for millennia. Its interpretation of fossils
was not overturned until after the Scientific Revolution. It was translated into
Latin and the other languages of Europe such as French.Some modern scholars,
such as Fielding H. Garrison, are of the opinion that modern geology began in
the Muslim world. Abu al-Rayhan al-Biruni (973-1048 AD) was one of the earliest
Muslim geologists, whose works included the earliest writings on the geology of
India. In China, the polymath Shen Kua (1031-1095) formulated a hypothesis for
the process of land formation: based on his observation of fossil shells in a
geological stratum in a mountain hundreds of miles from the ocean, he inferred
that the land was formed by erosion of the mountains and by deposition of silt.
19th Century geology revolved around the question of the Earth's exact age.
Estimates varied from a few 100,000 to billions of years. The most significant
advance in 20th century geology has been the development of the theory of plate
tectonics in the 1960s. Plate tectonic theory arose out of two separate
geological observations: seafloor spreading and continental drift. The theory
revolutionized the Earth sciences. The theory of continental drift was proposed
by Frank Bursley Taylor in 1908, expanded by Alfred Wegener in 1912 and by
Arthur Holmes, but wasn't broadly accepted until the late 1960s when the theory
of plate tectonics was developed. Learn Geology, SCHOOLS Geology, COLLEGES
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