Geology

Geology (from Greek γη- (ge-, "the earth") and λογος (logos, "word", "reason")) is the science and study of the Earth, its composition, structure, physical properties, history, and the processes that shape it. It is one of the Earth sciences.

History

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.

Related Topics:
China - Polymath - Shen Kua - Fossil - Shell - Stratum - Erosion - Mountain - Deposition - Silt

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The work on rocks Peri lithōn by Theophrastus, a student of Aristotle, remained authoritative for millennia. However, 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. Georg Bauer (Georg Agricola), a physician, summarized the knowledge of mining and metallurgy 1556.

Related Topics:
Theophrastus - Aristotle - Scientific Revolution - Latin - French - Georg Bauer - Mining - Metallurgy - 1556

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Georg Agricola (1494-1555) wrote the first systematic treatise about mining and smelting works, De re metallica libri XII, with an appendix Buch von den Lebewesen unter Tage (book of the creatures beneath the earth). He covered subjects like wind energy, hydrodynamic power, melting cookers, transport of ores, extraction of soda, sulfur and alum, and administrative issues. The book was published in 1556.

Related Topics:
Mining - Smelting - Wind energy - Hydrodynamic power - Ore - Soda - Sulfur - Alum - 1556

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By the 1700s Jean-Etienne Guettard and Nicolas Desmarest hiked central France and recorded their observations on geological maps; Guettard recorded the first observation of the volcanic origins of this part of France. James Hutton recorded his Theory of the Earth in the 1788 Transactions of the Royal Society of Edinburgh, later called uniformitarianism.

Related Topics:
1700s - Jean-Etienne Guettard - Nicolas Desmarest - Geological maps - Volcanic - James Hutton - 1788 - Uniformitarianism

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William Smith (1769-1839) drew some of the first geological maps and began the process of ordering rock strata (layers) by examining the fossils contained in them.

Related Topics:
William Smith - Rock strata

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James Hutton is often viewed as the first modern geologist. In 1785 he presented a paper entitled Theory of the Earth to the Royal Society of Edinburgh. In his paper, he explained his theory that the Earth must be much older than had previously been supposed in order to allow enough time for mountains to be eroded and for sediment to form new rocks at the bottom of the sea, which in turn were raised up to become dry land.

Related Topics:
James Hutton - 1785 - Royal Society of Edinburgh - Sediment

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Followers of Hutton were known as Plutonists because they believed that some rocks were formed by vulcanism which is the deposition of lava from volcanoes, as opposed to the Neptunists, who believed that all rocks had settled out of a large ocean whose level gradually dropped over time.

Related Topics:
Plutonists - Vulcanism - Volcano - Neptunists

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In 1811 Georges Cuvier and Alexandre Brongniart published their explanation of the antiquity of the Earth, inspired by Cuvier's discovery of fossil elephant bones in Paris. To prove this, they formulated the principle of stratigraphic succession of the layers of the earth. They were independently anticipated by William Smith's stratigraphic studies on England and Scotland.

Related Topics:
1811 - Georges Cuvier - Alexandre Brongniart - Stratigraphic - William Smith

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Sir Charles Lyell first published his famous book, Principles of Geology, in 1830 and continued to publish new revisions until he died in 1875. He successfully promoted the doctrine of uniformitarianism. This theory states that slow geological processes have occurred throughout the Earth's history and are still occurring today. In contrast, catastrophism is the theory that Earth's features formed in single, catastrophic events and remained unchanged thereafter. Though Hutton believed in uniformitarianism, the idea was not widely accepted at the time.

Related Topics:
Sir Charles Lyell - 1830 - 1875 - Uniformitarianism - Catastrophism

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By 1827 Charles Lyell's Principles of Geology reiterated Hutton's uniformitarianism, which influenced the thought of Charles Darwin.

Related Topics:
1827 - Charles Lyell - Charles Darwin

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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.

Related Topics:
Geology - Earth's exact age - 20th century - Plate tectonics - 1960s - Seafloor spreading - Continental drift - Earth sciences

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The theory of continental drift was proposed by Alfred Wegener in 1912 and by Arthur Holmes, but wasn't broadly accepted until the 1960s when the theory of plate tectonics was developed.

Related Topics:
Alfred Wegener - 1912 - Arthur Holmes - 1960s

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