Geologic provinces of the world (USGS)

Shield      Platform      Orogen      Basin      Large igneous province      Extended crust

Oceanic crust:      0–20 Ma      20–65 Ma      >65 Ma

In geology, a crust is the outermost solid shell of a planet or moon. Crust is chemically and mechanically different from underlying material. Crusts of Earth, our Moon, Mercury, Venus, and Mars have been generated largely by igneous processes, and these crusts are richer in incompatible elements than the underlying mantles. Crusts are also present on moons of outer planets and have formed by similar or analogous processes: for instance, Io, a moon of Jupiter, also has a crust formed by igneous processes. Image File history File links Download high resolution version (1200x637, 114 KB) Map of world geologic provinces. ... Image File history File links Download high resolution version (1200x637, 114 KB) Map of world geologic provinces. ... A geologic province is a spatial entity with common geologic attributes. ... The United States Geological Survey (USGS) is a scientific agency of the United States government. ... Shields are shown in orange. ... In geology, a platform is a continental area covered by relatively flat or gently tilted, mainly sedimentary strata, which overlie a basement of consolidated igneous or metamorphic rocks of an earlier deformation. ... // Orogeny (Greek for mountain generating) is the process of mountain building, and may be studied as a tectonic structural event, as a geographical event and a chronological event, in that orogenic events cause distinctive structural phenomena and related tectonic activity, affect certain regions of rocks and crust and happen within... A structural basin is a large-scale structural formation of rock strata formed by tectonic warping of previously flat lying strata. ... Large Igneous provinces (LIPS) were originally defined by Coffin and Eldholm (1992) as areas of Earths surface that contain very large volumes of magmatic rocks (typically basalt but including rhyolites) erupted over extremely short geological time intervals of a few million years or less. ... Age of oceanic crust Oceanic crust is the part of Earths lithosphere that surfaces in the ocean basins. ... Annum is a Latin noun meaning year. ... This article is about Earths moon. ... This article is about the planet. ... For other uses, see Venus (disambiguation). ... Adjectives: Martian Atmosphere Surface pressure: 0. ... Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... Incompatible element is a term used in petrology and geochemistry. ... Earth cutaway from core to exosphere. ... Atmosphere Surface pressure: trace Composition: 90% sulfur dioxide Io (eye-oe, IPA: , Greek Ῑώ) is the innermost of the four Galilean moons of Jupiter and, with a diameter of 3,642 kilometers, is the fourth largest moon in the Solar System. ... For other uses, see Jupiter (disambiguation). ...

Earth has the best characterized and perhaps the most complex crust of all the planets and moons in our solar system. An overview of our crust is provided in the entry on Structure of the Earth, and the two contrasting types of crust are discussed in entries on continental crust and oceanic crust. Despite the details known about Earth's crust, its early history is obscure. The rapidly growing base of knowledge about other bodies in the solar system provides insights into the beginnings of Earth history as well as into other possible paths of planetary evolution. Studies of the Moon have been particularly valuable for understanding the early Earth. This article is about the Solar System. ... Earth cutaway from core to exosphere. ... The thickness of the Earths crust (km). ... Age of oceanic crust Oceanic crust is the part of Earths lithosphere that surfaces in the ocean basins. ...

Perspective from the Moon

The Moon provides an unusual opportunity to study how crust can first form, for at least these two reasons. First, ancient crust is well-preserved because the Moon has never had plate tectonics or an atmosphere or surface water. Second, there are many extremely well-characterized samples of the crust from known locations.

The limited summary below is intended for comparative purposes, and much of the content is based on the overview of Hiesinger and Head (2006) ^[1] and other papers in the same volume. Much more information can be found in the complementary entries about the Geology of the Moon and the Moon. Exploring Shorty crater during the Apollo 17 mission to the Moon. ... This article is about Earths moon. ...

Most of the crust of the moon crystallized from magma formed as a consequence of intense meteorite bombardment in the early history of our solar system. A particularly large meteorite is thought to have collided with the forming Earth, and part of the material ejected into space by the collision accreted to form the Moon. As the Moon formed, the outer part of it is thought to have been molten, a “lunar magma ocean.” Plagioclase feldspar crystallized in large amounts from this magma ocean and floated towards the surface. The cumulate rocks form much of the crust. The upper part of the crust probably averages about 88% plagioclase (near the lower limit of 90% defined for anorthosite): the lower part of the crust may contain a higher percent of ferromagnesian minerals such as the pyroxenes and olivine, but even that lower part probably averages about 78% plagioclase.^[2] The underlying mantle is denser and olivine-rich. This article, which relates to the Moon, is a stub. ... Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ... This article does not cite any references or sources. ... Magma is molten rock located beneath the surface of the Earth (or any other terrestrial planet), and which often collects in a magma chamber. ... Cumulate rocks are igneous rocks formed by the accumulation of crystals from a magma either by settling or floating. ... Anorthosite is a phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar (90-100%), and a minimal mafic component (0-10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present. ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... The mineral olivine (also called chrysolite and, when gem-quality, peridot) is a magnesium iron silicate with the formula (Mg,Fe)2SiO4. ...

The thickness of the crust ranges between about 20 and 120 km. Crust on the far side of the moon averages about 12 km thicker than that on the near side. Estimates of average thickness fall in the range from about 50 to 60 km. Most of this plagioclase-rich crust formed shortly after formation of the moon, between about 4.5 and 4.3 billion years ago. Perhaps 10% or less of the crust consists of igneous rock added after formation of the initial plagioclase-rich material. The best-characterized and most voluminous of these later additions are the mare basalts formed between about 3.9 and 3.2 billion years ago. Minor volcanism continued after 3.2 billion years, perhaps as recently as 1 billion years ago. There is no evidence of crustal formation or deformation due to plate tectonics. For the cities, see Basalt, Colorado and Basalt, Idaho. ... The tectonic plates of the world were mapped in the second half of the 20th century. ...

Study of the Moon has established that a crust can form on a rocky planetary body significantly smaller than Earth. Although the radius of the Moon is only about a quarter that of Earth, the lunar crust has a significantly greater average thickness. This relatively thick crust formed almost immediately after formation of the Moon. Magmatism continued after the period of intense meteorite impacts ended about 3.9 billion years ago, but igneous rocks younger than 3.9 billion years make up only a minor part of the crust. Igneous rocks (etymology from Latin ignis, fire) are rocks formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... Igneous rocks (etymology from Latin ignis, fire) are rocks formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ...

Earth's crust

Earth cutaway from core to exosphere.

The crust of the Earth is composed of a great variety of igneous, metamorphic, and sedimentary rocks. The crust is underlain by the mantle. The upper part of the mantle is composed mostly of peridotite, a rock denser than rocks common in the overlying crust. The boundary between the crust and mantle is conventionally placed at the Mohorovičić discontinuity, a boundary defined by a contrast in seismic velocity. Earth's crust occupies less than 1% of Earth's volume. Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... This article is about Earth as a planet. ... The planetary core consists of the innermost layer(s) of a planet. ... [fAgot png|thumb|200px|right|Atmosphere diagram showing the exosphere and other layers. ... This article is about Earth as a planet. ... Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... The term Metamorphic can be associated with a number of meanings:- Metamorphic rock The term for rocks that have been transformed by extreme heat and pressure. ... Two types of sedimentary rock: limey shale overlain by limestone. ... Earth cutaway from core to exosphere. ... Peridotite xenolith from San Carlos, southwestern United States. ... Ordovician ophiolite in Gros Morne National Park, Newfoundland. ... Seismology (from the Greek seismos = earthquake and logos = word) is the scientific study of earthquakes and the movement of waves through the Earth. ...

The oceanic crust of the Earth is different from its continental crust. The oceanic crust is 5 km (3 mi) to 10 km (6 mi) thick^[3] and is composed primarily of basalt, diabase, and gabbro. The continental crust is typically from 30 km (20 mi) to 50 km (30 mi) thick, and it is mostly composed of less dense rocks than is the oceanic crust. Some of these less dense rocks, such as granite, are common in the continental crust but rare to absent in the oceanic crust. The continental crust and the oceanic crust are sometimes called sial and sima respectively. Due to the change in velocity of seismic waves it is believed that on continents at a certain depth sial becomes close in its physical properties to sima and the dividing line is called Conrad discontinuity. Age of oceanic crust Oceanic crust is the part of Earths lithosphere that surfaces in the ocean basins. ... The thickness of the Earths crust (km). ... Age of oceanic crust Oceanic crust is the part of Earths lithosphere that surfaces in the ocean basins. ... For the cities, see Basalt, Colorado and Basalt, Idaho. ... It has been suggested that this article or section be merged with Dolerite. ... Gabbro specimen. ... The thickness of the Earths crust (km). ... For other uses, see granite (disambiguation). ... typical Sial material, a Precambrian granite showing potassium feldspar (felsic) matrix For the Sial tribe of Pakistan, see Sial (tribe). ... Sima (Simplified Chinese: 司马; Traditional Chinese: 司馬; pinyin: ; Wade-Giles: Ssu-ma) is a Chinese family name. ... Body waves and surface waves Earthquake wave paths p-wave and s-wave from seismograph A seismic wave is a wave that travels through the Earth, most often as the result of a tectonic earthquake, sometimes from an explosion. ...

The temperature of the crust increases with depth, reaching values typically in the range from about 500 °C (900 °F) to 1,000 °C (1,800 °F) at the boundary with the underlying mantle. The crust and underlying relatively rigid mantle make up the lithosphere. Because of convection in the underlying plastic, although non-molten, upper mantle and asthenosphere, the lithosphere is broken into tectonic plates that move. The tectonic plates of the lithosphere on Earth. ... Convection in the most general terms refers to the movement of currents within fluids (i. ... In physics and materials science, plasticity is a property of a material to undergo a non-reversible change of shape in response to an applied force. ... Earth cutaway from core to exosphere. ... This article does not cite any references or sources. ... The tectonic plates of the world were mapped in the second half of the 20th century. ...

Partly by analogy to what is known about our Moon, Earth is considered to have differentiated from an aggregate of planetesimals into its core, mantle and crust within about 100 million years of the formation of the planet, 4.6 billion years ago. The primordial crust was very thin, and was likely recycled by much more vigorous plate tectonics and destroyed by significant asteroid impacts, which were much more common in the early stages of the solar system. Look up Aggregate in Wiktionary, the free dictionary. ... In cosmogony, planetesimals are objects thought to exist within solar nebulae. ... Earth cutaway from core to exosphere. ... The introduction of this article does not provide enough context for readers unfamiliar with the subject. ... The tectonic plates of the world were mapped in the second half of the 20th century. ... For other uses, see Asteroid (disambiguation). ...

The Earth has likely always had some form of basaltic crust, but the age of the oldest oceanic crust today is only about 200 million years. In contrast, the bulk of the continental crust is much older. The oldest continental crustal rocks on Earth have ages in the range from about 3.7 to 4.0 billion years ^[4] and have been found in the Narryer Gneiss Terrane in Western Australia, in the Acasta Gneiss in the Northwest Territories on the Canadian Shield, and on other cratonic regions such as those on the Fennoscandian Shield. A few zircons with ages as great as 4.3 billion years have been found in the Narryer Gneiss Terrane. The Narryer Gneiss Terrane complex is verifiably the oldest known portion of the crust on Earth. ... Slogan or Nickname: Wildflower State or the Golden State Other Australian states and territories Capital Perth Government Constitutional monarchy Governor Ken Michael Premier Alan Carpenter (ALP) Federal representation  - House seats 15  - Senate seats 12 Gross State Product (2005-06)  - Product ($m)  $107,910 (4th)  - Product per capita  $53,134/person... The Acasta Gneiss is a rock outcrop of Archaean tonalite gneiss in the Northwest Territories, Canada. ... For the former United States territory, see Northwest Territory. ... Canadian Shield Canadian Shield Landform. ... The Baltic Shield (or Fennoscandian Shield) is a segment of the Earths crust belonging to the East European Craton, representing a large part of Scandinavia, northwestern Russia and the northern Baltic Sea. ... The Narryer Gneiss Terrane complex is verifiably the oldest known portion of the crust on Earth. ...

The average age of the current Earth's continental crust has been estimated to be about 2.0 billion years.^[5] Most crustal rocks formed before 2.5 billion years ago are located in cratons. Such old continental crust and the underlying mantle lithosphere are less dense than elsewhere in the earth and so are not readily destroyed by subduction. Formation of new continental crust is linked to periods of intense orogeny or mountain building; these periods coincide with the formation of the supercontinents such as Rodinia, Pangaea and Gondwana. The crust forms in part by aggregation of island arcs including granite and metamorphic fold belts, and it is preserved in part by depletion of the underlying mantle to form buoyant lithospheric mantle. World geologic provinces. ... The tectonic plates of the lithosphere on Earth. ... Geometry of a subduction zone - insets to show accretionary prism and partial melting of hydrated asthenosphere. ... // Orogeny (Greek for mountain generating) is the process of mountain building, and may be studied as a tectonic structural event, as a geographical event and a chronological event, in that orogenic events cause distinctive structural phenomena and related tectonic activity, affect certain regions of rocks and crust and happen within... In geology, a supercontinent is a land mass comprising more than one continental core, or craton. ... In geology, Rodinia (from the Russian родина, or motherland) refers to one of the oldest known supercontinents, which contained most or all of Earths then-current landmass. ... For other uses, see Pangaea (disambiguation). ... For other uses of Gondwana and Gondwanaland, see Gondwana (disambiguation). ... An island arc is a type of archipelago formed by plate tectonics as one oceanic tectonic plate subducts under another and produces magma. ... For other uses, see granite (disambiguation). ... The term Metamorphic can be associated with a number of meanings:- Metamorphic rock The term for rocks that have been transformed by extreme heat and pressure. ... Earth cutaway from core to exosphere. ...

Composition of the continental crust

The continental crust has an average composition similar to that of the igneous rock, andesite. The composition tabulated below and the following discussion are based largely on the summary by Rudnick and Gao (2003).^[6] Continental crust is enriched in incompatible elements compared to the basaltic ocean crust and much enriched compared to the underlying mantle. Although the continental crust comprises only about 0.6 weight percent of the silicate Earth, it contains 20% to 70% of the incompatible elements. Igneous rocks (etymology from Latin ignis, fire) are rocks formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... A sample of andesite (dark groundmass) with amygdaloidal vesicules filled with zeolite. ... Incompatible element is a term used in petrology and geochemistry. ... For the cities, see Basalt, Colorado and Basalt, Idaho. ...

Plates in the crust of the earth, according to the plate tectonics theory

All the other constituents except water occur only in very small quantities, and total less than 1%. Estimates of average density for the upper crust range between 2.69 g/cm³ and 2.74 g/cm³ and for lower crust between 3.0 g/cm³ and 3.25 g/cm^3[3]. Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... The tectonic plates of the world were mapped in the second half of the 20th century. ...

References

1. ^ Herald Hiesinger and James W. Head III, 2006, New views of Lunar geoscience: An introduction and overview. Reviews in Mineralogy & Geochemistry 60, p. 1-81.
2. ^ Wieczorek, M. A., and Zuber, M. T., 2001, The composition and origin of the lunar crust: Constraints from central peaks and crustal thickness modeling. Geophysical Research Letters 28, p. 4023-4026.
3. ^ ^{a b} Structure and composition of the Earth. Australian Museum Online. Retrieved on 2007-09-14.
4. ^ P. J. Patchett and S. D. Samson, 2003, Ages and Growth ot the Continental Crust from Radiogenic Isotopes. In The Crust (ed. R. L. Rudnick) volume 3, pages 321-348 of Treatise on Geochemistry (eds. H. D. Holland and K. K. Turekian), Elsevier-Pergamon, Oxford
5. ^ A. I. S. Kemp and C. J. Hawkesworth, 2003, Granitic Perspectives on the Generation and Secular Evolution of the Contnental Crust. In The Crust (ed. R. L. Rudnick) volume 3, pages 349-410 of Treatise on Geochemistry (eds. H. D. Holland and K. K. Turekian), Elsevier-Pergamon, Oxford
6. ^ R. L. Rudnick and S. Gao, 2003, Composition of the Continental Crust. In The Crust (ed. R. L. Rudnick) volume 3, pages 1-64 of Treatise on Geochemistry (eds. H. D. Holland and K. K. Turekian), Elsevier-Pergamon, Oxford

Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 257th day of the year (258th in leap years) in the Gregorian calendar. ...

External links

• USGS Crust Thickness Map