Geology

Geology (from Greek language 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. Geologists have helped establish the age of the Earth at about 4.5 billion (4.5x10⁹) years, and have determined that the Earth's lithosphere, which includes the Crust (geology), is fragmented into tectonic plates that move over a rheid upper Mantle (geology) (asthenosphere) via processes that are collectively referred to as plate tectonics. Geologists help locate and manage the earth's natural resources, such as oil and coal, as well as metals such as iron, copper, and uranium. Additional economic interests include minerals such as asbestos, perlite, mica, phosphates, zeolites, clay, pumice, quartz, and silica, as well as elements such as sulfur, chlorine, and helium. 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 (planet)), etc., are also in use. The word "geology" was first used by Jean-Andr� Deluc in the year 1778 and introduced as a fixed term by Horace-B�n�dict de Saussure in the year 1779. An older meaning of the word was first used by Richard de Bury. He used it to distinguish between earthly and Theology jurisprudence. == History == In China, the polymath Shen Kua (1031 - 1095) formulated a hypothesis for the process of land formation: based on his observation of fossil animal 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 (geology) of silt. 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 language. Georg Bauer (Georg Agricola), a physician, summarized the knowledge of mining and metallurgy 1556. 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, hydropower, melting cookers, transport of ores, extraction of soda, sulfur and alum, and administrative issues. The book was published in 1556. By the 1700s Jean-Etienne Guettard and Nicolas Desmarest hiked central France and recorded their observations on Geologic map; Guettard recorded the first observation of the Volcano 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''. William Smith (geologist) (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. 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. Followers of Hutton were known as ''Plutonism '' because they believed that some rocks were formed by vulcanism which is the deposition of lava from volcanoes, as opposed to the ''Neptunism'', who believed that all rocks had settled out of a large ocean whose level gradually dropped over time. 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 Stratigraphy succession of the layers of the earth. They were independently anticipated by William Smith (geologist)'s stratigraphic studies on England and Scotland. 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 (science) . 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. [[Image:Wegener.jpg|thumb|right|Plate tectonics - seafloor spreading and continental drift illustrated on relief globe of the Field Museum ]] By 1827 Charles Lyell's ''Principles of Geology'' reiterated Hutton's uniformitarianism, which influenced the thought of Charles Darwin. 19th Century geology revolved around the question of the Age of the Earth. 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 Alfred Wegener in 1912 and by Arthur Holmes, but wasn't broadly accepted until the 1960s when the theory of plate tectonics was developed. == Important principles of geology == There are a number of important principles in geology. Many of these involve the ability to provide the relative ages of strata or the manner in which they were formed. The Principle of Intrusive Relationships concerns crosscutting Intrusion (geology)s. In geology, when an igneous intrusion cuts across a formation of sedimentary rock, it can be determined that the igneous intrusion is younger than the sedimentary rock. There are a number of different types of intrusions, including stocks, laccoliths, batholiths, Sill (geology) and Dike (geology). The Principle of Cross-cutting Relationships pertains to the formation of Geologic fault and the age of the sequences through which they cut. Faults are younger than the rocks they cut; accordingly, if a fault is found that penetrates some formations but not those on top of it, then the formations that were cut are older than the fault, and the ones that are not cut must be younger than the fault. Finding the key bed in these situations may help determine whether the fault is a normal fault or a thrust fault. The Principle of Inclusions and Components states that, with sedementary rocks, if inclusions (or ''clasts'') are found in a formation, then the inclusions must be older than the formation that contains them. For example, in sedimentary rocks, it is common for gravel from an older formation to be ripped up and included in a newer layer. A similar situation with igneous rocks occurrs when xenoliths are found. These foreign bodies are picked up as magma or lava flows, and are incorporated, later to cool in the matrix. As a result, xenoliths are older than the rock which contains them. The Principle of Uniformitarianism states that, the geologic processes observed in operation that modify the Earth's crust at present have worked in much the same way over geologic time. A fundamental principle of geology advanced by the 18th century Scottish physician and geologist James Hutton, is that "The Present is the Key to the Past." In Hutton's words: "the past history of our globe must be explained by what can be seen to be happening now." The Principle of Original Horizontality states that, the deposition of sediments occurs as essentially horizontal beds. Observation of modern marine and nonmarine sediments in a wide variety of environments supports this generalization (although cross-bedding is inclined, the overall orientation of cross-bedded units is horizontal). The Principle of Superposition states that, a sedimentary rock layer in a tectonically undisturbed sequence is younger than the one beneath it and older than the one above it. Logically a younger layer cannot slip beneath a layer previously deposited. This principle allows sedimentary layers to be viewed as a form of vertical time line, a partial or complete record of the time elapsed from deposition of the lowest layer to deposition of the highest bed. The Principle of Faunal Succession is based on the appearance of fossils in sedimentary rocks. As organisms exist at the same time period throughout the world, their presence or (sometimes) absence may be used to provide a relative age of the formations in which they are found. Based on principles laid out by William Smith (geologist) almost a hundred years before the publication of Charles Darwin's theory of evolution, the principles of succession were developed independent of evolutionary thought. The principle becomes quite complex, however, given the uncertainties of fossilization, the localization of fossil types due to lateral changes in habitat (facies change in sedimentary strata), and that not all fossils may be found globally at the same time. == Fields or related disciplines == * Earth science * economic geology ** mining ** petroleum geology * engineering geology * environmental geology * geoarchaeology * geochemistry **biogeochemistry **isotope geochemistry * geochronology * geodetics * geomicrobiology * geomorphology * geophysics * glaciology * historical geology * hydrogeology or geohydrology * oceanography * mineralogy * paleoclimatology * paleontology ** micropaleontology ** palynology * petrology * plate tectonics * sedimentology * seismology * soil science ** pedology (soil study) * speleology * stratigraphy ** biostratigraphy * structural geology * volcanology == Regional geology == *Geology of the Himalaya *Geology of the Alps *Glacial geology of the Genesee River ''(New York, Pennsylvania)'' == National geology == *Geology of Australia **Geology of Victoria *Geology of India **Sikkim#Geology *Geology of the United States of America **List_of_California-related_topics#Geology_of_California **Geology of the Grand Canyon area *Geology of the United Kingdom *Geology of Japan ==Planetary geology== *Mars_%28planet%29#Geology == See also == * Timeline of geology * List of geology topics * Geologist * Geologic modeling * Geologic timescale * Mineral * International Union of Geological Sciences (IUGS) * List of publications in geology == External links == * [http://www.ngi.no/ Norwegian Geotechnical Institute] * [http://www.geo-guide.de/ Geo-Guide] maintained by two German universities * James Hutton's [http://www.mala.bc.ca/~johnstoi/essays/Hutton.htm ''Theory of the Earth''] * James Hutton's [http://www.uwmc.uwc.edu/geography/hutton/hutton.htm ''Theory of the Earth & Abstract of the Theory of the Earth''] Geology Science Natural sciences bs:Geologija fa:زمین‌شناسی la:Geologia su:G�ologi th:ธรณีวิทยา vo:Talav

Geology

---- I think this statment is not correct! I don't want to modify the article as I'm quite new in WP and not english native-speaker. Please do it for me! "the Earth's crust is fragmented into tectonic plates that move over a semi-molten upper mantle (asthenosphere)" SHOULD BE "the Earth's lithosphere (which is composed by the crust and a part of the upper mantle called LID) is fragmented into tectonic plates that move over the asthenosphere (another part of the upper mantle), which is 5% melted." --User:129.11.76.216 11:11, 23 May 2005 (UTC) ---- Say, I recently wrote Teton Dam, and could use a geology person to use plain English to describe a few details of which I am fuzzy. My fields are math / chemistry, not geology. Any takers? -- user:dino ---- This page could use some serious expansion. Or should it be merely a gateway to more detailed pages on geology? Is there anyone willing to take a section? I might be able to do some work on History, for instance. User:Gwimpey 00:10, 10 May 2004 (UTC) ---- Although I think geology is way too big a topic to cover comprehensively (and comprehensibly!) on one page, I do think a gentle introduction to the basic concepts on this page would be in order. For instance, things to cover here might be: * More useful definition of what geology is about; i.e. what are the areas of interest and study. * An introduction to the structure and geological history of the Earth; timescales, maybe the periods etc * An introduction to rock types; maybe a description of some fundamental types * Processes; erosion; volcanic activity; plate tectonics; the rock cycle * Stratigraphy and palaeontology Phew that's a lot! I think it should all be covered within a few thousand words, with links to subject-specific articles for each topic for more details. - User:Thparkth 18:27, 14 May 2004 (UTC) ---- OK, I have started a WIP alternative "Geology" page at User:Thparkth/Geology. Please feel free to contribute. My prose is hopefully imaginative and interesting, but could hardly be called concise. Please do wade in and edit/change/add whatever. Eventually I would like this page to incorporate the above suggestions, and also the good stuff from the existing page. The intention is to replace the existing page, unless I hear strong opposition to that idea. - User:Thparkth 01:25, 19 May 2004 (UTC) == Geology Descriptions == I am a recent masters graduate of Geology and I should like to reply in reference to the request for ideas on how to edit the geology Section. Geology covers many disciplines, which could be used to catagorise this section for you. They include:- *''Economic Geology *''Geophysics'' *''Geodynamics, or Structural Geology'' *''Historical Geology'' *''Paleaontology'' *''Petrology'' *''Geochemistry'' *''Geological Mapping'' *''Mineralogy'' Each has several sub groups, which should cover the entire subject. I should be glad to edit one or two of the pages if required, as I specialise in Petrology and economic geology, and also dabble in volcanology. Heleanor Topliss--User:Pondering Frog 10:43, 7 Sep 2004 (UTC) ::Hi - don't just ''ponder'', jump right in :). Your expertise is welcome. Note I added a bit of formatting to your message above. This is a great learning experience. I've been ''playing'' here for a couple months now. I also recently (in geologic terms) earned a master's in economic geology. -User:Vsmith 18:14, 9 Oct 2004 (UTC) == Geography - geology? == ''Geology differs from Geography in that geology studies Earth without a focus on the human element...''
Wow! What a claim. Finding energy and mineral resourses; predicting seismic and volcanologic hazards ... There might be a ''human element'' focus involved. I deleted that nonsense. Let's get a better comparison or forget it. -User:Vsmith 04:45, 24 Oct 2004 (UTC) == remove pedology link == The link to pedology in the geology article should to be renamed soil sciences and removed to the science article under the heading earth sciences. This change is needed to maintain a NPOV, consistent with the International Council for Science which has accepted as equal Scientific Union members the IUSS and the IUGS. User:Paleorthid 17:44, 31 Oct 2004 (UTC) :Hmm... academic semantics and turf wars :-) Put soil science back in and renamed section to ''Fields or related disciplines''. Soil is a bit related to geology, without rocks, minerals, weathering, and erosion, there would be no soil to abuse and fertilize. -User:Vsmith 00:36, 1 Nov 2004 (UTC) ::That works. Thx for understanding. Semantic/turf deal inevitable. Soils curricula sufficient for a BS in soil science always a challenge to keep in class catalog. Soil Science departments get folded into ag, bio, env, eng, geog or geol depts. Natural to see soilsci as branch of same. Fallout in the not-academic world: state regulations get passed for soilsci practice to require non-soilsci license/reg (Sanitarians, PEs, or RPGs) or certif (crop or ag practitioners). That said, would have been lost mapping soils without my geomorphology class. Geo 60 Mineralogy leveled me tho. ouch. User:Paleorthid 06:28, 1 Nov 2004 (UTC) == Need a geologist == The Flood geology page is making some very bold and unsubstantiated claims. It would behoove a geologist to go over there and do some heavy editting if your up to the task of taking on the creationists. User:67.172.158.8 21:41, 6 Jan 2005 (UTC) :: I went to Flood geology and the talk page and saw a positive and unfolding discussion going on. For instance, creationists admitting that certain theories they had in the past were unsupportable, even within their community. This gets my attention because it speaks to a dynamic that we old-age-earth.ers would typically assume to be incompatible with biblical literalism. And I saw a gallant defense against some of the most damning criticisms one could make of the scientific credentials and sincerity of their supporters within the geologic profession. Look past the dogma, and you see a legitimate tension between uniformitarianianism as a model and our need to understand the effects of catastrophic events. Certainly geologists should visit the Flood geology page and review, contribute, and offer criticism. And look forward to a reasoned response. This free exchange of diverse views between professional scientists can only be good for geology. An invitation to engage in 'heavy editing' flamebait by an Anonymous_Coward sounds to me like a call to vandalism, and I hope you will join me in not taking that bait. User:Paleorthid 21:48, 8 Jan 2005 (UTC) ::Flood geology has gone through a major transition since two months ago and now seems to be ready to actually accept edits from those who know a bit about geology. In particular, it would be nice to have someone to come through and make substantitive critique of the page. We need someone familiar with editting geology articles to help tighten up the article and provide the alternative offered by actual science. Thank you. User:Joshuaschroeder 06:28, 5 Mar 2005 (UTC) == Sikkim == I need a someone to make sense of the geology subsection in the Sikkim article and see if it is noteworthy. User:Nichalp 18:10, Feb 13, 2005 (UTC) == New content heeds home == The history of science was getting too long, in mav's estimation. So I am looking for a new home for some of the content. Would it be allright with everyone if I injected some of the content here? User:Ancheta Wis 19:35, 29 Mar 2005 (UTC) == Manipulation of geological data == A new user has just asked me to look over his first article; I've made some comments on the formatting, etc., but it would be good if more expert users could take a look at it. I'm sure that everyone will be gentle... User:Mel Etitis (Μελ_Ετητης)">User talk:Mel Etitis 19:05, 7 Apr 2005 (UTC) ==Bunter== Could somebody have a go at starting Bunter (geology), please? User:Pigsonthewing 08:59, 17 Jun 2005 (UTC) == Continent == In the second paragraph of continent granite is described as an example of "metamorphic and sedimentary rock". Can someone check this? -- User:Ran (User talk:Ran) 17:04, Jun 19, 2005 (UTC)

Geology

Earth sciences fa:Category:زمين‌شناسی th:Category:ธรณีวิทยา

Geology

Would :Category:Geography belong here instead of directly in :Category:Natural sciences?-- User:Mic 08:21, 11 Jun 2004 (UTC) :It is now placed in :Category:Earth sciences. -- User:Mic 16:10, 11 Jun 2004 (UTC)

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