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جيولوجي'''ځمکپېژندنه''' (ځمکهیا پېژندنه) دا''جيولوجي'' په لومړي ځل د يونان له ژبې راوتلی ويېک دی او د ځمکې پېژندنې نه مانا او مفهوم داسې څرګندېږي . ځمکه پېژندنه هغه پوهه يا علم دی چې پکې د ځمکې څېره، مساهت ،ډول ، فيزيکي څرنګوالی (پږنۍ څرنګوالی) او د ځمکې د پېښليک (تاريخ ) پوره انځوريزه بشپړ پوهاوی او شننه پلاس راکوي او راښيي.
ځمکه پېژندنه هغه پوهه يا علم دی چې پکې د ځمکې څېره، مساهت ،ډول ، فيزيکي څرنګوالی (پږنۍ څرنګوالی) او د ځمکې د پېښليک (تاريخ ) پوره انځوريزه بشپړ پوهاوی او شننه پلاس راکوي او راښيي.
'''Geology''' (from [[Greek language|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 science]]s. [[Geologist]]s have helped establish the [[age of the Earth]] at about 4.6 billion (4.6x10<sup>9</sup>) years, and have determined that the Earth's [[lithosphere]], which includes the [[Crust (geology)|crust]], is fragmented into [[tectonic plates]] that move over a [[rheid|rheic]] upper [[Mantle (geology)|mantle]] ([[asthenosphere]]) via processes that are collectively referred to as [[plate tectonics]]. Geologists help locate and manage the earth's [[natural resource]]s, such as [[petroleum]] and [[coal]], as well as [[metals]] such as [[iron]], [[copper]], and [[uranium]]. Additional economic interests include [[gemstone]]s 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]].
[[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)|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]]. An older meaning of the word was first used by [[Richard de Bury]]. He used it to distinguish between earthly and [[Theology|theological]] 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 shell|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 [[mountain]]s and by [[Deposition (geology)|deposition]] of [[silt]].
The work on rocks ''Peri lithon'' 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|French]]. [[Georg Bauer]] (Georg Agricola), a physician, summarised the knowledge of [[mining]] and [[metallurgy]] in [[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|hydrodynamic power]], melting cookers, transport of [[ore]]s, extraction of [[soda]], [[sulfur]] and [[alum]], and administrative issues. The book was published in [[1556]].
Nicolaus Steno (1638-1686) is credited with the [[law of superposition]], the [[principle of original horizontality]], and the [[principle of lateral continuity]]: three defining principles of [[stratigraphy]].
By the [[1700s]] [[Jean-Etienne Guettard]] and [[Nicolas Desmarest]] hiked central France and recorded their observations on [[Geologic map|geological maps]]; Guettard recorded the first observation of the [[Volcano|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 (science)|uniformitarianism]]''.
[[William Smith (geologist)|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.
[[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|Plutonists]]'' because they believed that some rocks were formed by [[vulcanism]] which is the deposition of lava from [[volcano]]es, as opposed to the ''[[Neptunism|Neptunists]]'', 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|stratigraphic]] succession of the layers of the earth. They were independently anticipated by [[William Smith (geologist)|William Smith]]'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)|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.
[[دوتنه: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|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 revolutionised 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)|intrusions]]. 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, [[laccolith]]s, [[batholith]]s, [[Sill (geology)|sills]] and [[Dike (geology)|dikes]].
'''The Principle of Cross-cutting Relationships''' pertains to the formation of [[Geologic fault|faults]] 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 sedimentary 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 occurs when [[xenolith]]s 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.
[[وېشنيزه:ځمکه پېژندنه|ځمکه پېژندنه]]
'''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 generalisation (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)|William Smith]] almost a hundred years before the publication of [[Charles Darwin]]'s [[theory of evolution]], the principles of succession were developed independently of evolutionary thought. The principle becomes quite complex, however, given the uncertainties of fossilisation, the localisation 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|Mining geology]]
** [[Petroleum geology]]
* [[Engineering geology]]
* [[Environmental geology]]
* [[Geoarchaeology]]
* [[Geochemistry]]
** [[Biogeochemistry]]
** [[Isotope geochemistry]]
* [[Geochronology]]
* [[Geodetics]]
* [[Geomicrobiology]]
* [[Geomorphology]]
* [[Geophysics]]
* [[Glaciology]]
* [[Historical geology]]
* [[Hydrogeology]] or [[geohydrology]]
* [[Oceanography]]
** [[Marine geology]]
* [[Mineralogy]]
* [[Paleoclimatology]]
* [[Paleontology]]
** [[Micropaleontology]]
** [[Palynology]]
* [[Petrology]]
* [[Petrophysics]]
* [[Plate tectonics]]
* [[Sedimentology]]
* [[Seismology]]
* [[Soil science]]
** [[Pedology (soil study)]]
* [[Speleology]]
* [[Stratigraphy]]
** [[Biostratigraphy]]
* [[Structural geology]]
* [[Volcanology]]
== Regional geology ==
* [[Geology of the Alps]]
* [[Geology of the Appalachians]]
* [[Geology of the Himalaya]]
=== By Nations ===
* [[Geology of Australia]]
** [[Geology of the Australian Capital Territory]]
** [[Geology of Victoria]]
** [[Yilgarn craton|Geology of the Yilgarn Craton]]
* [[Geology of the Falkland Islands]]
* [[Geology of India]]
** [[Sikkim#Geology|Geology of Sikkim]]
* [[Geology of Japan]]
* [[Geology of Scotland]]
* [[Geology of the United Kingdom]]
** [[Geology of Dorset]]
** [[Geology of Hampshire]]
** [[Geology of Hertfordshire]]
** [[Geology of Shropshire]]
* [[Geology of the United States of America]]
** [[List of California-related topics#Geology of California|Geology of California]]
** [[Geology of Connecticut]]
** [[Geology of the Bryce Canyon area]]''(Utah)''
** [[Geology of the Canyonlands area]] ''(Utah)''
** [[Geology of the Capitol Reef area]] ''(Utah)''
** [[Geology of the Death Valley area]] ''(California)''
** [[Geology of the Grand Canyon area]] ''(Arizona)''
** [[Geology of the Grand Teton area]] ''(Wyoming)''
** [[Geology of the Lassen area]] ''(California)''
** [[Mount Adams (Washington)#Geology|Geology of Mount Adams]] ''(Washington)''
** [[Geology of Mount Shasta]] ''(California)''
** [[Geology of the Yosemite area]] ''(California)''
** [[Geology of the Zion and Kolob canyons area]] ''(Utah)''
** [[Glacial geology of the Genesee River]] ''(New York, Pennsylvania)''
== Planetary geology ==
* [[Geology of Mercury]]
* [[Geology of Venus]]
* [[Geology of the Moon]]
* [[Mars (planet)#Geology|Geology of Mars]]
* [[Jupiter#Physical Characteristics|Geology of Jupiter]]
* [[Saturn#Physical Characteristics|Geology of Saturn]]
* [[Uranus#Physical Characteristics|Geology of Uranus]]
* [[Neptune#Physical Characteristics|Geology of Neptune]]
* [[Pluto#Physical Characteristics|Geology of Pluto]]
== See also ==
* [[Timeline of geology]]
* [[List of rocks]]
* [[List of minerals]]
* [[List of geology topics]]
* [[List of rock textures]]
* [[Geologist]]
* [[Geologic modeling]]
* [[Geologic timescale]]
* [[Mineral]]
* [[International Union of Geological Sciences]] ([[IUGS]])
* [[List of publications in geology|Important publications in geology]]
== External links ==
* 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'']
{{Earth science}}
[[وېشنيزه:ځمکه پېژندنه| Earth_sciences|]]
[[af:Geologie]]
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