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This Sin-Kamen (Blue Rock) near Lake Pleshcheyevo used to be a Meryan shrine Credit: Viktorianec.
This is a blue rock, probably various copper minerals, from the Berkeley hills near San Francisco, California. Credit: Looie496.
This is an approximately natural color picture of the asteroid 243 Ida on August 28, 1993. Credit: NASA/JPL.

Sin-Kamen (Синь-Камень, in Russian literally – Blue Stone, or Blue Rock) is a type of pagan sacred stones, widespread in Russia, in areas historically inhabited by both Eastern Slavic (Russian), and Uralic tribes (Merya, Muroma[1]).

While in the majority of cases, the stones belonging to the Blue Stones type, have a black, or dark gray color, this particular stone [in the image] does indeed look dark blue, when wet.[2]

"Several types of rock surface materials can be recognized at the two sites [Viking Lander 1 and Viking Lander 2]; dark, relatively 'blue' rock surfaces are probably minimally weathered igneous rock, whereas bright rock surfaces, with a green/(blue + red) ratio higher than that of any other surface material, are interpreted as a weathering product formed in situ on the rock."[3]

At second right is an approximately natural color image of the asteroid 243 Ida. "There are brighter areas, appearing bluish in the picture, around craters on the upper left end of Ida, around the small bright crater near the center of the asteroid, and near the upper right-hand edge (the limb). This is a combination of more reflected blue light and greater absorption of near infrared light, suggesting a difference in the abundance or composition of iron-bearing minerals in these areas."[4]

"The [Sloan Digital Sky Survey] SDSS “blue” asteroids are related to the C-type (carbonaceous) asteroids, but not all of them are C-type. They are a mixture of C-, E-, M-, and P-types."[5]

RocksEdit

 
Rock outcrop occurs along a mountain creek near Orosí, Costa Rica. Credit: Dirk van der Made.

Rocks are a bound aggregate of minerals with usually a large geographic extent.

Occasionally, a rock is composed of only one mineral. But a crystal of the mineral fluorite in your hand is a stone rather than a rock.

A rock is a naturally occurring solid aggregate of one or more minerals or mineraloids.

Def. any "natural material with a distinctive composition of minerals"[6] is called a rock.

Beta particlesEdit

Excessive "26Mg [has] been reported in meteoritic carbonaceous chondrites [...] which demonstrate an excess of 26Mg of up to 40% combined with essentially solar concentrations of 24Mg and 25Mg. Many of the data are well correlated with the 27Al content of the samples, and this is interpreted as evidence that the excess 26Mg has arisen from the in situ decay (via positron emission and electron capture) of the ground state of 26Al in these minerals."[7]

X-raysEdit

 
The image contains a 27.70 g fragment of the Carancas meteorite fall. The scale cube is 1 cm3. Credit: Meteorite Recon.

On September 20, the X-Ray Laboratory at the Faculty of Geological Sciences, Mayor de San Andres University, La Paz, Bolivia, published a report of their analysis of a small sample of material recovered from the impact site. They detected iron, nickel, cobalt, and traces of iridium — elements characteristic of the elemental composition of meteorites. The quantitative proportions of silicon, aluminum, potassium, calcium, magnesium, and phosphorus are incompatible with rocks that are normally found at the surface of the Earth.[8]

In X-ray wavelengths, many scientists are investigating the scattering of X-rays by interstellar dust, and some have suggested that astronomical X-ray sources would possess diffuse haloes, due to the dust.[9]

UltravioletsEdit

 
This is a black-and-white image of 2 Pallas taken with the Hubble Telescope in 2007 with UV filter. Credit: Hubble Space Telescope/STScI.{{free media}}
 
Clementine image of Aristarchus and surroundings is mapped onto simulated topography. Credit: NASA.

"Spectrally blue (B-type) asteroids are rare, with the second discovered asteroid, Pallas, being the largest and most famous example."[10]

"[T]he negative optical spectral slope of some B-type asteroids is due to the presence of a broad absorption band centered near 1.0 μm. The 1 μm band can be matched in position and shape using magnetite (Fe3O4), which is an important indicator of past aqueous alteration in the parent body. ... Observations of B-type asteroid (335) Roberta in the 3 μm region reveal an absorption feature centered at 2.9 μm, which is consistent with the absorption due to phyllosilicates (another hydration product) observed in CI chondrites. ... at least some B-type asteroids are likely to have incorporated significant amounts of water ice and to have experienced intensive aqueous alteration."[10]

In 1911, Professor Robert W. Wood used ultraviolet photography to take images of the crater area. He discovered the plateau had an anomalous appearance in the ultraviolet, and an area to the north appeared to give indications of a sulfur deposit.[11] This colorful area is sometimes referred to as "Wood's Spot", an alternate name for the Aristarchus Plateau.

Spectra taken of this crater during the Clementine mission were used to perform mineral mapping.[12] The data indicated that the central peak is a type of rock called anorthosite, which is a slow-cooling form of igneous rock composed of plagioclase feldspar. By contrast the outer wall is troctolite, a rock composed of equal parts plagioclase and olivine.

The Aristarchus region was part of a Hubble Space Telescope study in 2005 that was investigating the presence of oxygen-rich glassy soils in the form of the mineral ilmenite. Baseline measurements were made of the Apollo 15 and Apollo 17 landing sites, where the chemistry is known, and these were compared to Aristarchus. The Hubble Advanced Camera for Surveys was used to photograph the crater in visual and ultraviolet light. The crater was determined to have especially rich concentrations of ilmenite, a titanium oxide mineral that could potentially be used in the future by a lunar settlement for extracting oxygen.[13]

OpticalsEdit

The analysis of high-resolution, near-infrared and [ultraviolet] UV spectra obtained by the Galileo spacecraft and from the ground has revealed various non-ice materials: magnesium- and iron-bearing hydrated silicates,[14] carbon dioxide,[15] sulfur dioxide,[16] and possibly ammonia and various organic compounds.[14][17] Spectral data indicate that the moon's surface is extremely heterogeneous at the small scale. Small, bright patches of pure water ice are intermixed with patches of a rock–ice mixture and extended dark areas made of a non-ice material.[14][18]

BluesEdit

"Nine out of 10 well-characterized Apollo 17 breccia matrices fall into Group 2, and this includes both the blue-grey breccias which are the dominant rock type at this site"[19].

"A 1953 telescopic photograph of a flash on the Moon is the only unequivocal record of the rare crash of an asteroid-sized body onto the lunar surface. ... A search of images from the Clementine mission reveals an ∼1.5-km high-albedo, blue, fresh-appearing crater with an associated ejecta blanket at the location of the flash."[20]

In terms of reflectance from the lunar surface, "the very dark 'blue' maria [are] such as found in Mare Tranquillitatis."[21]

"[T]he slope of the reflectance spectrum in the blue and ultraviolet ... is directly related to the percent TiO2 in the [lunar] surface soil (Charette et al., 1974)."[22]

CyansEdit

“[A]ll the blue basalt types (high in UV/VIS ratio [0.40/0.56 µm]) are also the darkest mare soils.”[23] Both Luna 24 and Apollo 12 soil samples are from mare soils that reflect primarily cyan that is likely due to the presence of TiO2 in the soils.[22]

"Previous work has suggested that a cyan color in the multispectral frame represents highland material, and that yellows and greens are freshly excavated basalts. However, we have recently found that a cyan color can also result from a freshly excavated high-Ti basalt."[24]

GreensEdit

 
This colour mosaic was assembled from 18 images taken by Galileo's imaging system through a green filter. Credit: NASA/JPL/USGS.

"During its mission, the Galileo spacecraft returned a number of images of Earth's only natural satellite. Galileo surveyed the moon on Dec. 7, 1992, on its way to explore the Jupiter system in 1995-1997."[25]

"This color mosaic was assembled from 18 images taken by Galileo's imaging system through a green filter. On the upperleft is the dark, lava-filled Mare Imbrium, Mare Serenitatis (middle left), Mare Tranquillitatis (lower left), and Mare Crisium, the dark circular feature toward the bottom of the mosaic. Also visible in this view are the dark lava plains of the Marginis and Smythii Basins at the lower right. The Humboldtianum Basin, a 400-mile impact structure partly filled with dark volcanic deposits, is seen at the center of the image."[25]

OrangesEdit

"Crystallized spheres of orange glass from Shorty Crater at the Apollo 17 site are ... the characteristic ingredient of the dark mantling deposit of the Taurus-Littrow region."[26]

"The reflectance properties of the orange glass are highly distinctive. There are two broad absorption bands, one near 1.15 µm and the other near 1.9 µm that arise from Fe2+ on octahedral and tetrahedral sites, respectively ... The weak absorption near 0.5 µm probably arises from Ti3+, and the absorption edge extending into the visible region is due largely to oxygen-titanium charge transfer".[26]

EarthEdit

 
This is an aerial image of the ice cap on Ellesmere Island, Canada. Credit: National Snow and Ice Data Center.
 
This oblique astronaut photograph from the International Space Station (ISS) captures a white-to-grey volcanic ash and steam plume extending westwards from the Soufriere Hills volcano. Credit: NASA Expedition 21 crew.
 
This is an aerial view of the Barringer Meteor Crater about 69 km east of Flagstaff, Arizona. Credit:D. Roddy, U.S. Geological Survey.

The first image on the right is an aerial image of the ice cap on Ellesmere Island, Canada.

Oblique images such as the one on the second lower right are taken by astronauts looking out from the ISS at an angle, rather than looking straight downward toward the Earth (a perspective called a nadir view), as is common with most remotely sensed data from satellites. An oblique view gives the scene a more three-dimension quality, and provides a look at the vertical structure of the volcanic plume. While much of the island is covered in green vegetation, grey deposits that include pyroclastic flows and volcanic mud-flows (lahars) are visible extending from the volcano toward the coastline. When compared to its extent in earlier views, the volcanic debris has filled in more of the eastern coastline. Urban areas are visible in the northern and western portions of the island; they are recognizable by linear street patterns and the presence of bright building rooftops. The silver-grey appearance of the Caribbean Sea surface is due to sun-glint, which is the mirror-like reflection of sunlight off the water surface back towards the hand-held camera on-board the ISS. The sun-glint highlights surface wave patterns around the island.

The image on the left is an aerial view of the Barringer Meteor Crater. Fragments of an iron-nickel meteorite have been found in the crater confirming its origin as an impact crater.

MoonEdit

 
Planetary geologist and NASA astronaut Harrison "Jack" Schmitt collects lunar samples during the Apollo 17 mission. Credit: NASA.
 
This image shows the lunar meteorite Allan Hills 81005. Credit: NASA.

In the image at right, planetary geologist and NASA astronaut Harrison "Jack" Schmitt collects lunar samples during the Apollo 17 mission.

"Recent scans of magnetized lunar rocks that show no evidence of effects from cosmic impacts now provide strong evidence that the moon had a magnetic field".[27]

"Earth's magnetic field is currently 50 microteslas in strength. The early moon may have had a magnetic field that was bigger, maybe up to more than 70 microteslas."[28]

Allan Hills A81005 or ALH A81005 (sometimes also named without the "A" in front of the number) was the first lunar meteorite found on Earth.[29] It was found in 1982 in the Allan Hills at the end of the Transantarctic Mountains, during a meteorite gathering expedition (ANSMET).[30]

ALH A81005 was found on 17 January 1982 by John Schutt and Ian Whillans.[31][32] It is named after the Allan Hills, a mountain chain in Antarctica where many meteorites are gathered by expeditions.[30] The large number of meteorites collected in Antarctica and the lack of geographic terms that could be used for names have led to the adaption of the "Antarctic rules" for meteorite naming. Every meteorite found in Antarctica receives the names of the collection area (Allan Hills) and a number. The number consists of the year the expedition started "81" and a three digit number that is given out consecutively (005). The "A" in front of the number stands for meteorites collected by ANSMET expeditions and can be considered optional.[33] The definition of the year is used because the year changes during the Austral summer season (December to March) and this avoids samples from one expedition having different years. This is the reason ALH A81005 has the year "81" in its name despite being found on 17 January 1982.[33]

ALH A81005 measures 3 × 2.5 × 3 centimetres (1.18 × 0.98 × 1.18 in). It has a dark fusion crust on the outside. The interior is made up of a black to dark grey groundmass (matrix) with larger grey and white angular crystals (clasts). This appearance is typical for breccias, including those originating on Earth. The size of the larger crystals ranges from sub-millimeter to 8 millimetres (0.31 in) in diameter.[30]

Thin section analysis revealed that the crystals are mostly plagioclase, with some pyroxene and olivine. It was also discovered that the meteorite had similarities to terrestrial gabbro or basalt. Microprobe analysis showed that the plagioclase was very calcium-rich. The crystals are a solid solution of 97% anorthite and 3% albite. The pyroxenes have a variable composition lying between enstatite, ferrosilite and wollastonite. The olivine is a solid solution of 11 to 40% fayalite with the rest being forsterite]].[30] ALH A81005 is classified as a "lunar anorthosite breccia" and belongto the group "lunar anorthosite" (abbreviated Lun-A).[30]

M3 found a rock dominated by Mg-spinel with no detectable pyroxene or olivine present (<5%) occurring along the western inner ring of Moscoviense Basin (as one of several discrete areas). The occurrence of this spinel does not easily fit with current lunar-crustal evolution models.[34]

Rock formsEdit

Rock forms are geomorphic land forms made of specific rock types.

ArêtesEdit

 
This is an image of Punta dell'Alp from monte Pelvo. Credit: F Ceragioli.

Def. a "very thin ridge of rock"[35] is called an arête.

"An earlier [...] glacial episode, herein termed the Altonah Glaciation, is indicated by an extensive lateral moraine beyond the mouth of Yellowstone canyon as well as moraines in Lake Fork and Uinta River canyons. At higher elevations, alpine glacial landforms, including cirques, rock glaciers, arêtes, and hanging valleys are ubiquitous."[36]

"Arêtes and cols are most common in the south-central and southwestern Uinta Mountains, where accumulation areas of glaciers were largest and the development of ice caps that drained into multiple valleys was common. In the south-central Uintas, the most prominent arêtes have more than 450 m of relief and are more than 10 km in length. In the southeastern Uintas, rounded unglaciated divides locally termed “bollies” are more common than narrow arêtes. Examples of these features include broad divides that separate glacial valleys in the headwaters of Dry Fork and Ashley Creeks [...]."[36]

CanyonsEdit

 
This is a view of the Grand Canyon in Arizona, USA. Credit: Mike Buchheit.

On the right is an example of a river canyon, specifically the Grand Canyon in Arizona, USA.

Def. a "valley, especially a long, narrow, steep valley, cut in rock by a river"[37] is called a canyon, or a river canyon.

Def. a deep gorge is called a canyon.

CliffsEdit

 
This cliff is part of a karst landscape formed by water and plants on calcareous (probably) limestone. Credit: Pavle Cikovac.
 
An eroded boulder clay cliff is shown. Credit: Eric Jones.
 
A red cliff along US287 between Lander and Dubois in Wyoming, near Wind Canyon. Credit: Wing-Chi Poon.
 
Cliffs of Moher is in East, Ireland. Credit: Tobias Helfrich.

The cliff in the image on the right is part of a karst landscape formed by water and plants on calcareous (probably) limestone.

"This photo [on the left] shows clearly why these glacial deposits are called boulder clay, consisting as they are of clay and stones of various sizes up to and including large boulders. Till is another name for boulder clay."[38] The image is of an eroded boulder-clay cliff near to Trefor, Gwynedd, Great Britain.

Def. a "vertical (or nearly vertical) rock face"[39] is called a cliff.

GlaciersEdit

 
Briksdalsbreen is a part of the Jostedalsbreen glacier in Norway. Credit: Donarreiskoffer.

Def. "a mass of ice that originates on land, usually having an area larger than one tenth of a square kilometer"[40] is called a glacier.

MountainsEdit

 
Low winter sun reflects off Skopphornet and Sunnmøre alps (Sykkylven) in Norway. Credit: "color line".

Def. a "large mass of earth and rock, rising above the common level of the earth or adjacent land, usually given by geographers as above 1000 feet in height (or 304.8 metres), though such masses may still be described as hills in comparison with larger mountains"[41] is called a mountain.

PavementsEdit

 
Limestone pavement is above Malham Cove in the Yorkshire Dales. Credit: Lupin.
 
This shows limestone pavement in Haute Savoie, France. Credit: f.corageoud.
 
Desert pavement is near Barstow, California. Credit: Wilson44691.
 
The "Tesselated Pavement“ is the result of an orthogonal joint pattern in the rock. Credit: JJ Harrison.
 
Grooves and striations are on exhumed Permian glacial pavement. Credit: Bahudhara.

Def. a more or less horizontal, hard expanse of bare rock as a surface is called a pavement.

On the right are two images of a limestone pavement which is part of a karst topography.

On the left is a desert pavement in southeastern California.

A pavement such as the one on the second left covered with pieces that are similarly shaped is referred to as a tessellated pavement.

Volcanic bombsEdit

 
This is an accretionary lava ball. Credit: J. D. Griggs, USGS HVO.
 
This is a volcanic bomb found in the Mojave Desert National Preserve by Rob McConnell. Credit: Wilson44691.
 
This is a picture of a lavabomb at Strohn, Germany. Credit: Jhintzbe.

Def. "distinctively shaped [natural] projectiles ... which acquired their shape essentially before landing"[42] are called bombs.

Def. a bomb "ejected from a volcanic vent"[42] is called a volcanic bomb.

Volcanic bombs can be thrown many kilometres from an erupting vent, and often acquire aerodynamic shapes during their flight.

The image at top right is an "[a]ccretionary lava ball [coming] to rest on the grass after rolling off the top of an ‘a‘a flow in Royal Gardens subdivision. Accretionary lava balls form as viscous lava is molded around a core of already solidified lava."[43]

Volcanic bombs cool into solid fragments before they reach the ground. Because volcanic bombs cool after they leave the volcano, they do not have grains making them extrusive igneous rocks. Volcanic bombs can be thrown many kilometres from an erupting vent, and often acquire aerodynamic shapes during their flight.

Volcanic bombs can be extremely large; the 1935 eruption of Mount Asama in Japan expelled bombs measuring 5–6 m in diameter up to 600 m from the vent. A large volcanic bomb is shown in the third image at right from Strohn, Germany.

Volcanic bombs are known to occasionally explode from internal gas pressure as they cool, but explosions are rare. Bomb explosions are most often observed in 'bread-crust' type bombs.

Ribbon or cylindrical bombs form from highly to moderately fluid magma, ejected as irregular strings and blobs. The strings break up into small segments which fall to the ground intact and look like ribbons. Hence, the name "ribbon bombs". These bombs are circular or flattened in cross section, are fluted along their length, and have tabular vesicles.

Spherical bombs also form from high to moderately fluid magma. In the case of spherical bombs, surface tension plays a major role in pulling the ejecta into spheres.

Spindle, fusiform, or almond/rotational bombs are formed by the same processes as spherical bombs, though the major difference being the partial nature of the spherical shape. Spinning during flight leaves these bombs looking elongated or almond shaped; the spinning theory behind these bombs' development has also given them the name 'fusiform bombs'. Spindle bombs are characterised by longitudinal fluting, one side slightly smoother and broader than the other. This smooth side represents the underside of the bomb as it fell through the air.

Cow pie bombs are formed when highly fluid magma falls from moderate height; so the bombs do not solidify before impact (they are still liquid when they strike the ground). They consequently flatten or splash and form irregular roundish disks, which resemble cow-dung.

Bread-crust bombs are formed if the outside of the lava bombs solidifies during their flights. They may develop cracked outer surfaces as the interiors continue to expand.

Cored bombs are bombs that have rinds of lava enclosing a core of previously consolidated lava. The core consists of accessory fragments of an earlier eruption, accidental fragments of country rock or, in rare cases, bits of lava formed earlier during the same eruption.

Rock structuresEdit

 
The image shows rock strata in Cafayate, Argentina. Credit: travelwayoflife.
 
The image shows an anticline in the Barstow Formation (Miocene) at Calico Ghost Town near Barstow, California USA. Credit: Wilson44691.

The image at the right shows rock strata in Cafayate, Argentina, the subject of stratigraphy.

Structural geology is the study of the three-dimensional distribution of rock units with respect to their deformational histories.

Marginal marinesEdit

 
This is a marginal marine sequence from southwestern Utah, USA. Credit: Wilson44691.

The marginal marine sequence on the right has been dated to the Middle Triassic.

Rock typesEdit

 
This rock shows a common facies of the Piégut-Pluviers granodiorite, northwestern Massif Central, France. Credit: Rudolf Pohl.
 
A metamorphic rock deformed during the Variscan orogeny, Vall de Cardós, Lérida, Spain. Credit: PePeEfe.

Usually rock types consist of sedimentary, metamorphic and igneous.

 
This image shows the sedimentary rock layers at Zabriskie Point in Death Valley, USA. Credit: Brigitte Werner (werner22brigitte).

MeteoritesEdit

 
Martian meteorite EETA79001 is a shergottite. Credit: NASA.{{free media}}

Def. a meteorite that is known to have originated on the Moon is called a lunar meteorite.

The meteorite called Allan Hills 81005 resembled some rocks brought back from the Moon by the Apollo program.[44]

Yamato 791197 is another lunar meteorite.

About 134 lunar meteorites have been discovered so far (as of October, 2010), perhaps representing more than 50 separate meteorite falls (i.e., many of the stones are "paired" fragments of the same meteoroid). The total mass is more than 46 kg.

Meteorites have been found on the Moon[45][46]

Many of the meteorites that are found on Earth turn out to be from the Moon.

So far seifertite has only been found in Martian[47][48] and lunar meteorites.[49]

EucritesEdit

 
A 175g individual is of the Millbillillie meteorite shower, a eucrite achondrite that fell in Australia in 1960. Credit: H. Raab.

Def. an "achondritic meteoritic rock consisting chiefly of pigeonite and anorthite"[50] is called a eucrite.

Igneous rocksEdit

Def. "one of the major groups of rock that makes up the crust of the Earth; formed by the cooling of molten rock, either below the surface (intrusive) or on the surface (extrusive)"[51] is called an igneous rock.

Igneous rocks are often divided into intrusive and extrusive by either grain size or glassiness.

AndesitesEdit

 
Close view is of andesite lava flow from Brokeoff Volcano, California. Credit: United States of America Geological Survey.

Def. a "class of fine-grained intermediate [..] rock [...] containing mostly plagioclase feldspar"[52] is called an andesite.

"Andesite is a gray to black volcanic rock with between about 52 and 63 weight percent silica (SiO2). Andesites contain crystals composed primarily of plagioclase feldspar and one or more of the minerals pyroxene (clinopyroxene and orthopyroxene) and lesser amounts of hornblende. At the lower end of the silica range, andesite lava may also contain olivine. Andesite magma commonly erupts from stratovolcanoes as thick lava flows, some reaching several km in length. Andesite magma can also generate strong explosive eruptions to form pyroclastic flows and surges and enormous eruption columns. Andesites erupt at temperatures between 900 and 1100° C."[53]

AnorthositesEdit

 
Anorthosite is a mafic intrusive igneous rock composed predominantly of plagioclase. Credit: Thamizhpparithi Maari.{{free media}}

Def. a "phaneritic, [...] rock characterized by a predominance of plagioclase feldspar"[54] is called an anorthosite.

Anorthosite on Earth can be divided into five types:[55]

  1. Archean-age anorthosites
  2. Proterozoic anorthosite (also known as massif or massif-type anorthosite) – the most abundant type of anorthosite on Earth[56]
  3. Layers within Layered Intrusions (e.g., Bushveld Igneous Complex and Stillwater igneous complex intrusions)
  4. Mid-ocean ridge and transform fault anorthosites
  5. Anorthosite xenoliths in other rocks (often granites, kimberlites, or basalts).

Plagioclase crystals are usually less dense than magma; so, as plagioclase crystallizes in a magma chamber, the plagioclase crystals float to the top, concentrating there.[57][56][55]

Lunar anorthosites constitute the light-coloured areas of the Moon's surface and have been the subject of much research.[58]

Proterozoic anorthosites were emplaced during the Proterozoic Eon (ca. 2,500–542 Ma), though most were emplaced between 1,800 and 1,000 Ma.[56]

Large volumes of ultramafic rocks are not found in association with Proterozoic anorthosites.[59]

BasaltsEdit

 
This is an example of a basalt. Credit: USGS.

Def. a "hard mafic [...] rock of varied mineral content"[60] is called a basalt.

"Basalt is a hard, black volcanic rock with less than about 52 weight percent silica (SiO2). Because of basalt's low silica content, it has a low viscosity (resistance to flow). Therefore, basaltic lava can flow quickly and easily move > 20 km from a vent. The low viscosity typically allows volcanic gases to escape without generating enormous eruption columns. Basaltic lava fountains and fissure eruptions, however, still form explosive fountains hundreds of meters tall. Common minerals in basalt include olivine, pyroxene, and plagioclase. Basalt is erupted at temperatures between 1100 to 1250° C."[61]

"Basalt is the most common rock type in the Earth's crust (the outer 10 to 50 km). In fact, most of the ocean floor is made of basalt."[61]

"Huge outpourings of lava called "flood basalts" are found on many continents. The Columbia River basalts, erupted 15 to 17 million years ago, cover most of southeastern Washington and regions of adjacent Oregon and Idaho."[61]

"Basaltic magma is commonly produced by direct melting of the Earth's mantle, the region of the Earth below the outer crust. On continents, the mantle begins at depths of 30 to 50 km."[61]

"Shield volcanoes, such as those that make up the Islands of Hawai`i, are composed almost entirely of basalt."[61]

CarbonatitesEdit

 
Carbonatite from Jacupiranga, Brazil, is a rock composed of calcite, magnetite and olivine. Credit: Eurico Zimbres.
 
Carbonatite lava is at Ol Doinyo Lengai volcano, Tanzania. Credit: Thomas Kraft, Kufstein.
 
This magnesiocarbonatite is from Verity-Paradise Carbonatite Complex of British Columbia. Specimen is 75 mm wide. Credit: James St. John.
 
Okaite is from the Oka Carbonatite Complex, Oka Niobium Mine, Oka, Quebec. Credit: James St. John.

Def. any "intrusive igneous rock having a majority of carbonate minerals"[62] is called a carbonatite.

DacitesEdit

 
Close view is of dacite lava from the May 1915 eruption of Lassen Peak, California. Credit: USGS.

Def. a rock with a high iron content is called a dacite.

"Dacite lava is most often light gray, but can be dark gray to black. Dacite lava consists of about 63 to 68 percent silica (SiO2). Common minerals include plagioclase feldspar, pyroxene, and amphibole. Dacite generally erupts at temperatures between 800 and 1000°C. It is one of the most common rock types associated with enormous Plinian-style eruptions. When relatively gas-poor dacite erupts onto a volcano's surface, it typically forms thick rounded lava flow in the shape of a dome."[63]

"Even though it contains less silica than rhyolite, dacite can be even more viscous (resistant to flow) and just as dangerous as rhyolites. These characteristics are a result of the high crystal content of many dacites, within a relatively high-silica melt matrix. Dacite was erupted from Mount St. Helens 1980-86, Mount Pinatubo in 1991, and Mount Unzen 1991-1996."[63]

GabbrosEdit

 
Gabbro specimen is from Rock Creek Canyon, eastern Sierra Nevada, California. Credit: Mark A. Wilson, Department of Geology, The College of Wooster.

Def. a dark, coarse-grained plutonic rock of crystalline texture, consisting mainly of pyroxene, plagioclase feldspar, and often olivine is called a gabbro.

Def. "a coarsely crystalline, igneous rock consisting of lamellar pyroxene and labradorite"[64] is called a gabbro.

As with diamictites, rock definitions should be without regard to origin.

GranitesEdit

 
View is of polished granite. Credit: Dake.
 
The color of a granite usually comes from the color of the feldspar. Credit: Luis Fernández García.
 
Granite such as this contains potassium feldspar, plagioclase feldspar, quartz, biotite and/or amphibole. Credit: Friman.

Def. a very hard, granular, crystalline, rock consisting mainly of quartz, mica, and feldspar is called a granite.

GranodioritesEdit

 
Here's a photo of a granodiorite. Credit: Zerohuman.

Def. a "rock similar to granite, but containing more plagioclase than potassium feldspar"[65] is called a granodiorite.

HawaiitesEdit

 
Geological sample is on display at the House of the Volcano, Reunion Island. Credit: David Monniaux.

Def. an "olivine basalt intermediate between alkali olivine and mugearite"[66] is called a hawaiite.

MonzogranitesEdit

 
Core sample is of Rochovce granite, coarse-grained biotite monzogranite (75.6 ± 1.1 Ma - Cretacous). Credit: Pelex.

Rochovce granite, composing the coring on the right, is a coarse-grained biotite monzogranite.

PeridotitesEdit

 
Peridotite specimen is displayed. Credit: USGS.

Def. a "rock consisting of small crystals of olivine, pyroxene and hornblende"[67] is called a peridotite.

RhyolitesEdit

 
A rhyolite boulder near Carn Alw shows the characteristic pattern of swirling or parallel layers called flow banding caused by the molten magma meeting a hard surface before cooling and setting. Credit: ceridwen.
 
Flow banding is in rhyolite lava from Mono-Inyo Craters volcanic chain, California (black bands composed of obsidian). Credit: USGS.

Def. a rock "of felsic composition, with aphanitic to porphyritic texture"[68] is called a rhyolite.

"Rhyolite is a light-colored rock with silica (SiO2) content greater than about 68 weight percent. Sodium and potassium oxides both can reach about 5 weight percent. Common mineral types include quartz, feldspar and biotite and are often found in a glassy matrix. Rhyolite is erupted at temperatures of 700 to 850° C."[69]

"Rhyolite can look very different, depending on how it erupts. Explosive eruptions of rhyolite create pumice, which is white and full of bubbles. Effusive eruptions of rhyolite often produce obsidian, which is bubble-free and black."[69]

"Some of the United States' largest and most active calderas formed during eruption of rhyolitic magmas (for example, Yellowstone in Wyoming, Long Valley in California and Valles in New Mexico)."[69]

"Rhyolite often erupts explosively because its high silica content results in extremely high viscosity (resistance to flow), which hinders degassing. When bubbles form, they can cause the magma to explode, fragmenting the rock into pumice and tiny particles of volcanic ash."[69]

SyenitesEdit

 
This is a piece of syenite. Credit: USGS.
 
Rock name is särnaite (leucocratic variety of nepheline syenite) and it is from Sweden. Credit: Siim Sepp.

Def. an "igneous rock composed of feldspar and hornblende"[70] is called a syenite.

On the left is a leucocratic variety of nepheline syenite from Sweden called särnaite.

TonalitesEdit

 
A piece of tonalite on red granite gneiss from Tjörn in Sweden. Credit: Ingwik.

Def. an "igneous, plutonic rock composed mainly of plagioclase"[71] is called a tonalite.

Metamorphic rocksEdit

Def. "one of the major groups of rock that makes up the crust of the Earth; consists of pre-existing rock mass in which new minerals or textures are formed at higher temperatures and greater pressures than those present on the Earth's surface"[72] is called a metamorphic rock.

AmphibolitesEdit

 
Garnet bearing amphibolite is from Val di Fleres, Italy. Credit: Bernabè Egon.
 
Amphibolite is from Cape Cod, Massachusetts. Credit: B.W. Hallett, V. F. Paskevich, L.J. Poppe, S.G. Brand, and D.S. Blackwood, USGS.

Def. any "of a class of [...] rock composed mainly of amphibole with some quartz etc"[73] is called an amphibolite.

On the left is foliated amphibolite, sample 81MW0005, a borehole sample from under Cape Cod in Massachusetts in USA. It is made of the minerals plagioclase (35%), hornblende (20%), biotite (20%), epidote (15%), quartz (9%), and trace oxides and sphene. Plagioclase is mostly fine grained and subhedral and occurs in the matrix. Fine-grained hornblende occurs as anhedral pleochroic green-tan crystals. Biotite is partly, but not entirely aligned in the foliation, suggesting that deformation took place before a secondary growth of biotite. Epidote is anhedral, and sometimes rimmed by biotite. Quartz occurs in 2 mm-thick aggregates and shows subgrain development.

AnthracitesEdit

 
Lump of anthracite was extracted from the Ibbenbüren underground coal mine, located in Ibbenbüren, Germany. Credit: Educerva.

Def. a "form of carbonized ancient plants; the hardest and cleanest-burning of all the coals; hard coal"[74] is called anthracite.

Def. a coal of a hard variety that contains relatively pure carbon is called an anthracite.

Anthracite is the most metamorphosed type of coal (but still represents low-grade metamorphism), in which the carbon content is between 92% and 98%.[75][76]

BlueschistsEdit

 
This blueschist example is from Ile de Groix, France. Credit: Arlette1.

Def. a "rock containing glaucophane"[77] is called a blueschist.

 

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Diagram showing metamorphic facies in pressure-temperature space. The domain of the graph corresponds to circumstances within the Earth's crust and upper mantle.

A metamorphic facies is a set of metamorphic mineral assemblages that were formed under similar pressures and temperatures.[78] The assemblage is typical of what is formed in conditions corresponding to an area on the two dimensional graph of temperature vs. pressure (See diagram at right).[78] Rocks which contain certain minerals can therefore be linked to certain tectonic settings, times and places in geological history of the area.[78] The boundaries between facies (and corresponding areas on the temperature v. pressure graph), are wide, because they are gradational and approximate.[78] The area on the graph corresponding to rock formation at the lowest values of temperature and pressure, is the range of formation of sedimentary rocks, as opposed to metamorphic rocks, in a process called diagenesis.[78]

Blueschist is a metavolcanic rock that forms by the metamorphism of basalt and rocks with similar composition at high pressures and low temperatures, approximately corresponding to a depth of 15 to 30 kilometers and 200 to ~500 degrees Celsius. The blue color of the rock comes from the presence of the mineral glaucophane. Blueschists are typically found within orogenic belts as terranes of lithology in faulted contact with greenschist or rarely eclogite facies rocks. ... Blueschist, as a rock type, is defined by the presence of the minerals glaucophane + ( lawsonite or epidote ) +/- jadeite +/- albite or chlorite +/- garnet +/- muscovite in a rock of roughly basaltic composition. Blueschist often has a lepidoblastic, nematoblastic or schistose rock microstructure defined primarily by chlorite, phengitic white mica, glaucophane, and other minerals with an elongate or platy shape. Grain size is rarely coarse, as mineral growth is retarded by the swiftness of the rock's metamorphic trajectory and perhaps more importantly, the low temperatures of metamorphism and in many cases the anhydrous state of the basalts. However, coarse varieties do occur. Blueschists may appear blue, black, gray, or blue-green in outcrop.

GneissesEdit

 
This gneiss is the property of museum of geology at the University of Tartu. Credit: Siim Sepp.

Def. a "rock having bands or veins, but not schistose"[79] is called a gneiss.

GranulitesEdit

 
This is a granulite from Slovakia. Credit: Helix84.

Def. "fine-grained [...] rock composed chiefly of feldspar, quartz, and garnets"[80] is called a granulite.

Granulites are a class of high-grade metamorphic rocks of the granulite facies that have experienced high-temperature and moderate-pressure metamorphism that are medium to coarse–grained and mainly composed of feldspars sometimes associated with quartz and anhydrous ferromagnesian minerals, with granoblastic texture and gneissose to massive structure.[81]

HornfelsEdit

 
This is a sample of banded hornfels from Borok quarry in Novosibirsk. Credit: Fed.

The hornfels shown on the right were formed from the heating of sandstones and siltstones by the Insskoy series of granite intrusions.

Maw sit sitEdit

 
Maw sit sit is a very rare, complex, polymineralic metamorphic rock. Credit: James St. John.

Maw sit sit, also known as jade-albite, is a gemstone found exclusively in northern Burma, first identified in 1963 by the late Swiss gemologist, Edward Gubelin, and was named after the village close to where it was first found in the foothills of the Himalayas.[82]

Typically maw sit sit is green with distinctive dark-green to black veins, is technically a rock rather than a mineral, composed of several different minerals, including kosmochlor (also known as ureyite), varying amounts of chromium-enriched jadeite, and albite feldspar.[83]

Maw sit sit can have a refractive index ranging from 1.52-1.68,[84][85] and a hardness rating of 6 to 7 on the Mohs scale.

MarblesEdit

 
This is a block of white marble. Credit: USGS.
 
Mississippian marble is in Big Cottonwood Canyon, Wasatch Mountains, Utah. Credit: commons:User:Wilson44691:Mark A. Wilson.

On the right is a block of white marble.

The left shows Mississippian marble in Big Cottonwood Canyon, Wasatch Mountains, Utah.

PhyllitesEdit

 
This is a sample of phyllite, a metamorphic rock. Credit: USGS.

A sample of a phyllite is on the right.

QuartzitesEdit

 
This quartzite shows banding. Credit: Siim Sepp.

Def. "a [...] rock consisting of interlocking grains of quartz"[86] is called a quartzite.

In a quartzite, fractures occur through the quartz grains. In a sedimentary rock composed of quartz grains, the rock fractures around the quartz grains.

SchistsEdit

 
This is a detail of schist, a foliated metamorphic rock. Credit: Michael C. Rygel.

At right is an image of schist.

SlatesEdit

 
The image shows finely layered slate perhaps with occasional dolomite layers exposed on a beach in Cornwall, UK. Credit: Si Griffiths.
 
The image shows folds in slate and quartzite of the Meguma Group near the Ovens, Nova Scotia, Canada. Credit: Michael C. Rygel.
 
This is a cyan colored slate. USGS.

Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. It is the finest grained foliated metamorphic rock.[87] Foliation may not correspond to the original sedimentary layering, but instead is in planes perpendicular to the direction of metamorphic compression.[87] Slate is frequently grey in color, especially when seen, en masse, covering roofs. However, slate occurs in a variety of colors even from a single locality; for example, slate from North Wales can be found in many shades of grey, from pale to dark, and may also be purple, green or cyan.

Def. a "fine-grained homogeneous [...] rock composed of clay or [...] ash which [...] cleaves easily into thin layers"[88] is called a slate.

Sedimentary rocksEdit

Def. "one of the major groups of rock that makes up the crust of the Earth; formed by the deposition of either the weathered remains of other rocks, the results of biological activity, or precipitation from solution"[89] is called a sedimentary rock.

AeolianitesEdit

 
Holocene eolianite is on Long Island, Bahamas. Credit: Wilson44691.

Def. a "rock formed from dune sand, often calcareous"[90] is called an aeolianite.

ArgillitesEdit

 
This is a piece of black argillite from Haida Gwaii. Credit: Gbuchana.
 
Greyish chunks of graptolitic argillite in front of Pakri Cliff, yellowish and white chunks are limestone. Credit: Siim Sepp.

Def. a "fine-grained sedimentary rock, intermediate between shale and slate, sometimes used as a building material"[91] is called an argillite.

ArkosesEdit

 
Arkose can have grains of K-feldspar (pinkish-orangish) and quartz (gray). Credit: James St. John.

Def. a "sedimentary rock consisting of small fragments of feldspar and quartz similar to a coarse sand"[92] is called an arkose.

BrecciasEdit

 
Tertiary breccia is at Resting Springs Pass, Mojave Desert, California. Credit: Wilson44691.
 
This unusual breccia is cemented by azurite and malachite, Morenci Mine, Arizona. Credit: James St. John.

Def. a "rock composed of angular fragments in a matrix that may be of a similar or a different material"[93] is called a breccia.

CalcarenitesEdit

 
The Pietra di Bismantova in the northern Appennine (Emilia Romagna region, northern Italy) is an example of calcarenite formation.

Def. a "form of limestone (or dolomite) composed of sand sized grains derived from the erosion of older rocks"[94] is called a calcarenite.

ConglomeratesEdit

 
The boulder is of conglomerate with cobble-sized clasts. Credit: Jstuby.
 
Carmelo Formation (Conglomerate) is at Point Lobos. Credit: Brocken Inaglory.

Def. a "rock consisting of gravel or pebbles embedded in a matrix"[95] is called a conglomerate.

Clastic rocksEdit

 
Thin section is of a clast (sand grain), derived from a basalt scoria. Vesicles (air bubbles) can be seen throughout the clast. Plane light above, cross-polarized light below. Scale box is 0.25 mm. Credit: Qfl247.

Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock, where a clast is a fragment of geological detritus,[96] chunks and smaller grains of rock broken off other rocks by physical weathering.[97]

ClaystonesEdit

 
Glacial Lake Missoula claystone is shown. Credit: Qfl247.
 
Claystone is in Slovakia. Credit: Pelex.

Def. a "rock composed of fine, clay particles"[98] is called a claystone.

CoalsEdit

 
Bituminous coal is a sedimentary rock. Credit: USGA.
 
Continental United States coal regions are mapped. Credit: USGS.

Def. "a black rock formed from prehistoric plant remains, composed largely of carbon and burned as a fuel"[99] is called a coal.

DiamictitesEdit

 
Boulder of diamictite of the Precambrian Mineral Fork Formation is lithified glacial till, along the Elephant Head Trail, Antelope Island, Utah. Credit: Jstuby.

Def. "nonsorted, noncalcareous terrigenous deposits composed of sand and/or larger particles dispersed through a muddy matrix"[100] are called diamictons.

Def. a lithified diamicton is called a diamictite.[100]

"Such rocks have in common a mixed, ill-sorted, disperse-megaclastic lithology with a great to extreme range of size grades."[100] The definitions of these rocks are "without regard to origin".[100]

Def. a " sedimentary, calcareous conglomerate containing a mixture of particles; mixtite"[101] is called a diamictite.

GreensandsEdit

 
A roadcut within the Llano Uplift on Texas Highway 1431 about 18 km northwest Marble Falls, Texas, exposes greensand of the Lion Mountain Sandstone (Cambrian) in the lower unit. Notice the normal fault cutting through the formation. Credit: Erimus.

Def. a "greenish sandstone containing glauconite"[102] is called a greensand.

GreywackesEdit

 
This is a sample of greywacke. Credit: www.mineraly.sk.

Def. a "hard dark sandstone with poorly sorted angular grains of quartz, feldspar, and small rock fragments in a compact, clay-fine matrix"[103] is called a greywacke.

GritstonesEdit

 
The Salt Cellar, a gritstone tor on Derwent Edge in the Peak District, England. Credit: Mick Knapton.

Def. a "form of sedimentary rock, similar to sandstone but coarser"[104] is called a gritstone.

LiasEdit

 
Lower Lias sequence is exposed at Nash Point, Glamorgan, Wales. Credit: Wilson44691.

Def. a "stratigraphic group from the lower Jurassic period, consisting of thin layers of blue limestone [present in parts of southern England]"[105] is called a lias.

LimestonesEdit

 
Layers of alpine limestone are dated to the Triassic. Credit: Gikü.

The middle Triassic layers of alpine limestone in the image on the right were deposited on the bottom of a shallow sea.

LithificationEdit

 
Differentially cemented & eroded sandstone occur in the Eocene of Fantasy Canyon, Utah, USA. Credit: James St. John.

Def. the "compaction and cementation of sediment into rock"[106] is called lithification.

Def. a "subdivision of any stratigraphic unit that has characteristic lithologic features"[107] is called a lithofacies.

Def. the "formation of sedimentary rock"[108] is called lithogenesis.

Def. "an element that forms silicates or oxides and is concentrated in the minerals of the Earth's crust"[109] is called a lithophile.

"The rocks are quartzose sandstones that were deposited on the eastern shore of ancient Lake Uinta, which existed during the Eocene. Some wisps and ribbons of dark-colored, magnetite-rich sand are present in the sandstone. The variety of chaotic rockforms at Fantasy Canyon are quite diverse - these cannot be explained by ordinary weathering and erosion. Close examination shows that erosion has acted upon differentially cemented sandstone. The sandstone has not undergone complete lithification and diagenesis - groundwater lobes have preferentially cemented portions of the sandstone, especially immediately adjacent to joint planes. The poorly-cemented sandstone was easily eroded & the better-cemented sandstone remains."[110]

"Fantasy Canyon [is located] between Red Wash & Coyote Wash, Chapita Wells Gas Field, west-northwest of the town of Bonanza & south-southeast of the town of Vernal & east of the town of Ouray, northeastern Utah, USA."[110]

MudstonesEdit

 
Mudstone formation is on Lyme Regis East Beach. Credit: Ballista.
 
Sample is of mudstone. Credit: Manishwiki15.
 
Red mudrock is in the Ragged Reef Formation (Pennsylvanian), Cumberland Basin, Nova Scotia. Credit: Michael C. Rygel.

Def. a "fine-grained sedimentary rock whose original constituents were clays or muds"[111] is called a mudstone.

OolitesEdit

 
Ooids occur on the surface of a limestone; Carmel Formation (Middle Jurassic) of southern Utah. Credit: .
 
Thin-section is of calcitic ooids from an oolite within the Carmel Formation (Middle Jurassic) of southern Utah. Credit: .

Def. a "rock consisting of spherical grains within a mineral cortex accreted around a nucleus, often of quartz grains"[112] is called an oolite.

PelitesEdit

Def. a "sedimentary rock containing very fine particles"[113] is called a pelites.

PhosphoritesEdit

 
Peloidal phosphorite is from the Phosphoria Formation, Simplot Mine, Idaho, specimen 4.6 cm wide. Credit: James St. John.
 
Fossiliferous peloidal phosphorite specimen is 4.7 cm across, from Yunnan Province, China. Credit: James St. John.

Def. "a sedimentary rock rich in phosphate minerals such as apatite"[114] is called a phosphorite.

RadiolaritesEdit

 
Radiolarian chert outcrop is near Cambria, California, where individual beds range from about 2 to 5 cm thick Credit: Peter D. Tillman.

Def. "the sedimentary rock formed from" "radiolarian ooze"[115] is called a radiolarite.

SandstonesEdit

 
Bunter Sandstone (detail), Hopstone, Shropshire, has layers of coloured pebbles often found in this Triassic rock, where this image shows about one metre (height) of sandstone. Credit: Roger Kidd.
 
Outcrop of Kangaroo Creek Sandstone is in Clarence Moreton Basin, New South Wales. Credit: Yendor of yinn.

Def. a "sedimentary rock produced by the consolidation and compaction of sand, cemented with clay etc"[116] is called a sandstone.

Sandstone classification by the Dott scheme uses the relative abundance of quartz, feldspar, and lithic framework grains and the abundance of a muddy matrix between the larger grains.[117]

ShalesEdit

 
The outcrop's striking layers, some at angles to each other, is a pattern called crossbedding. Credit: NASA/JPL-Caltech/MSSS.
 
Marcellus shale shown along Rt 174 just south of Slate Hill Rd, Marcellus, NY. Credit: Lvklock.
 
Black Shale occurs with pyrite. Credit: Rob Lavinsky.

Def. a "fine-grained [...] rock of a thin, laminated, and often friable, structure"[118] is called a shale.

SiltstonesEdit

 
A well-developed veined network, a fossilised soil structure, extends down from the top of a greyish red siltstone unit, and is underlain by a zone of calcareous nodules. Credit: P. J. Barrett, B. P. Kohn, R. A. Askin & J. G. McPherson.
 
Siltstone is at UAT, Estonia. Credit: Siim Sepp.

At the upper right is a small portion of the stratigraphic column between the Hatherton and MacKay glaciers in Antarctica. The top rock layer is a greyish red siltstone. The next downward is a greenish grey siltstone penetrated by sinuous tubes that may be roots or root-like structures. Underlaying this is "a zone of calcareous nodules."[119]

"The Beacon Supergroup (Barrett, 1970) in the Transantarctic Mountains is largely a flat-lying, nonmarine sequence from Devonian or older to Jurassic in age. It consists of the Taylor Group (Devonian or older), a quartzose sandstone sequence, and the Victoria Group (Permian and Triassic), dominantly a coal-bearing sandstone-siltstone sequence (Harrington, 1965)."[119]

"The Taylor Group comprises up to 1,450 m of quartzose sandstone, with smaller conglomerate, arkosic and shaly units [...]. [The] youngest Taylor Group unit [is] the Aztec Siltstone [of which the image at the right exhibits]."[119]

Def. a "sedimentary rock whose composition is intermediate in grain size between the coarser sandstone and the finer mudstone"[120] is called a siltstone.

TaconitesEdit

 
Taconite, in the United States, is a hard, silica-rich iron ore mined in the Lake Superior region. Credit: USGS.{{free media}}

"This rock is widely spread over the whole length of the Mesabi, and being different from anything found elsewhere and peculiar to this horizon of the Taconic, has been called taconyte by the writer."[121]

Taconite is a variety of iron formation, an iron-bearing (over 15% iron) sedimentary rock, in which the iron minerals are interlayered with quartz, chert, or carbonate, of the Precambrian Biwabik Iron Formation of northeastern Minnesota, bearing a superficial resemblance to iron-bearing rocks from the Taconic Mountains of New York state.[121]

TravertinesEdit

 
This is an example of a travertine. Credit: USGS.

Def. "light, porous form of concretionary limestone (or calcite)"[122] is called a travertine.

TurbiditesEdit

 
Turbidites (interbedded with mudstones/siltstones) from the Ross Sandstone Formation. Credit: USGS.
 
Turbidite (Gorgoglione Flysch) is from Miocene, South Italy. Credit: Geologist.

Def. "sea-bottom deposits formed by massive slope failures where rivers have deposited large deltas"[123] are called turbidites.

"Turbidites [shown in the image on the right] are sea-bottom deposits formed by massive slope failures where rivers have deposited large deltas. These slopes fail in response to earthquake shaking or excessive sedimentation load. The temporal correlation of turbidite occurrence for some deltas of the Pacific Northwest suggests that these deposits have been formed by earthquakes."[123]

"Turbidites (interbedded with mudstones/siltstones) from the Ross Sandstone Formation Turbidite system of Namurian age in County Clare, Western Ireland. The sandstone beds were formed in a deep basin by turbidites coming from a delta area."[123]

HadeanEdit

Def.

  1. "the geologic eon from about 4,600 to 3,800 million years ago; marked by the formation of the solar system, a stable Earth-Moon orbit and the first rocks"[124] or
  2. the "eon before 4,000 Ma"[125]

is called the Hadean.

"[U]ranium-lead dating [has been conducted] on fragments of the mineral zircon extracted from Apollo 14 lunar samples. The pieces of zircon were minuscule — no bigger than a grain of sand."[126]

"Size doesn't matter, they record amazing information nonetheless! The moon holds "so much magic ... the key to understand how our beautiful Earth formed and evolved."[127]

More "zircons from Apollo 14 samples [from the moon's Fra Mauro highlands collected in February 1971 are being studied], but [are not expected] to change [the] estimate of 4.51 billion years for the moon's age, possibly 4.52 billion years at the most."[126]

"It would be more a double-checking than anything else."[127]

Regardless "of how the moon came to be — one big strike at Earth, many smaller ones or even none at all — you still end up at the end solidifying the moon as we know it today."[127]

"We finally pinned down a minimum age for the moon formation, regardless of how it formed."[127]

See alsoEdit

ReferencesEdit

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  2. Бердников, В. Синий камень Плещеева озера // Наука и жизнь. – 1985. – № 1. – С. 134–139. (Russian)
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