query: the upper mantle below the earth 's crust is known as the

pos: Mantle (geology) overlying crust make up tectonic plates, which move over the asthenosphere. The Earth's mantle is divided into three major layers defined by sudden changes in seismic velocity: The lower ~200 km of the lower mantle constitutes the D" (D-double-prime) layer, a region with anomalous seismic properties. This region also contains LLSVPs and ULVZs. The top of the mantle is defined by a sudden increase in seismic velocity, which was first noted by Andrija Mohorovičić in 1909; this boundary is now referred to as the Mohorovičić discontinuity or "Moho". The upper mantle is dominantly peridotite, composed primarily of variable proportions of

pos: Earth about under the oceans to for the continents. The crust and the cold, rigid, top of the upper mantle are collectively known as the lithosphere, and it is of the lithosphere that the tectonic plates are composed. Beneath the lithosphere is the asthenosphere, a relatively low-viscosity layer on which the lithosphere rides. Important changes in crystal structure within the mantle occur at below the surface, spanning a transition zone that separates the upper and lower mantle. Beneath the mantle, an extremely low viscosity liquid outer core lies above a solid inner core. The Earth's inner core might rotate at a

pos: Earth plate boundaries, earthquakes, volcanic activity, mountain-building, and oceanic trench formation can occur. The tectonic plates ride on top of the asthenosphere, the solid but less-viscous part of the upper mantle that can flow and move along with the plates. As the tectonic plates migrate, oceanic crust is subducted under the leading edges of the plates at convergent boundaries. At the same time, the upwelling of mantle material at divergent boundaries creates mid-ocean ridges. The combination of these processes recycles the oceanic crust back into the mantle. Due to this recycling, most of the ocean floor is less than old. The

pos: Mid-ocean ridge new oceanic crust at mid-ocean ridges is the "mantle conveyor" (see image). However, there have been some studies which have shown that the upper mantle (asthenosphere) is too plastic (flexible) to generate enough friction to pull the tectonic plate along. Moreover, unlike in the image above, mantle upwelling that causes magma to form beneath the ocean ridges appears to involve only its upper , as deduced from seismic tomography and from studies of the seismic discontinuity at about . The relatively shallow depths from which the upwelling mantle rises below ridges are more consistent with the "slab-pull" process. On the

pos: Crust (geology) crustal rocks formed before 2.5 billion years ago are located in cratons. Such old continental crust and the underlying mantle asthenosphere are less dense than elsewhere in Earth and so are not readily destroyed by subduction. Formation of new continental crust is linked to periods of intense orogeny; 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. A theoretical protoplanet named

pos: Delamination (geology) likely to occur where there are high mantle temperatures. This limits this phenomenon to arc environments, volcanic rifted margins and continental areas undergoing extension. The asthenosphere rises until it comes into contact with the base of the lower crust, causing the lower crust and lithospheric mantle to start to peel away. Slumping, cracking, or plume erosion facilitates the intrusion of underlying asthenosphere. Potential energy that drives the delamination is released as the low density, hot asthenosphere rises and replaces the higher density, cold lithosphere. Separation of lowermost crust and lithospheric mantle is controlled by the effective viscosity of the upper

pos: Rio Grande rift starting about 35 Ma. The largest-scale manifestation of rifting involves a pure-shear rifting mechanism, in which both sides of the rift pull apart evenly and slowly, with the lower crust and upper mantle (the lithosphere) stretching like taffy. This extension is associated with very low seismic velocities in the upper mantle above approximately 400 km depth associated with relatively hot mantle and low degrees of partial melting. This intrusion of the asthenosphere into the lithosphere and continental crust is thought to be responsible for nearly all of the volcanism associated with the Rio Grande rift. The sedimentary fill of the

pos: Flat slab subduction the subducting plate and upper plate pinch out the mantle wedge. Upon the failure of the flat slab, the mantle wedge can again start circulating hot asthenosphere (1300 degrees C) in an area that has been heavily hydrated, but that had not produced any melt; this leads to widespread ignimbritic volcanism, which is seen in both the Andean flat slab effected regions and the western United States. Adakites are dacitic and andesitic magmas that are highly depleted in heavy rare-earth elements and high strontium/yttrium ratios and may be derived of melting of the oceanic crust. Adakites are thought to erupt

neg: Structure of the Earth obducted onto the continental crust and preserved as ophiolite sequences. Many rocks now making up Earth's crust formed less than 100 million (1) years ago; however, the oldest known mineral grains are about 4.4 billion (4.4) years old, indicating that Earth has had a solid crust for at least 4.4 billion years. Earth's mantle extends to a depth of 2,890 km, making it the thickest layer of Earth. The mantle is divided into upper and lower mantle. The upper and lower mantle are separated by the transition zone. The lowest part of the mantle next to the core-mantle boundary is

neg: Cobb hotspot a depth of 11 kilometres (6.8 mi) beneath the volcano. The magma flows at a rate of 0.3 to 0.8 m³/s. The caldera is 1,450 metres (4,760 ft) below sea level. Hotspots are formed when plumes of magma from the lower mantle upwells to the crust of Earth and breaks through the surface crust, whether that be oceanic crust or continental. This movement of magma breaks through the upper mantle, or the lithosphere, and creates a volcanic spot. This does not mean that all volcanoes are hotspots, some are created through interactions at plate boundaries. Tectonic plates move over hotspots

neg: Geophysics S-waves in the outer core. This indicates that the outer core is liquid, because liquids cannot support shear. The outer core is liquid, and the motion of this highly conductive fluid generates the Earth's field. The inner core, however, is solid because of the enormous pressure. Reconstruction of seismic reflections in the deep interior indicate some major discontinuities in seismic velocities that demarcate the major zones of the Earth: inner core, outer core, mantle, lithosphere and crust. The mantle itself is divided into the upper mantle, transition zone, lower mantle and "D′′" layer. Between the crust and the mantle is

neg: Crust (geology) only planet in our Solar System with plate tectonics. The crust is a thin shell on the outside of the Earth, accounting for less than 1% of Earth's volume. It is the top component of lithosphere: a division of Earth's layers that includes the crust and the upper part of the mantle. The lithosphere is broken into tectonic plates that move, allowing heat to escape from the interior of the Earth into space. The crust lies on top of the mantle, a configuration that is stable because the upper mantle is made of peridotite and so is significantly denser than

neg: Crust (geology) the crust. The boundary between the crust and mantle is conventionally placed at the Mohorovičić discontinuity, a boundary defined by a contrast in seismic velocity. The crust of the Earth is of two distinctive types: Because both continental and oceanic crust are less dense than the mantle below, both types of crust "float" on the mantle. This is isostasy, and it's also one of the reasons continental crust is higher than oceanic: continental is less dense and so "floats" higher. As a result, water pools in above the oceanic crust, forming the oceans. The temperature of the crust increases with

neg: Structure of the Earth discontinuity (a second order discontinuity). The uppermost mantle together with the crust constitutes the lithosphere. The crust-mantle boundary occurs as two physically different events. First, there is a discontinuity in the seismic velocity, which is most commonly known as the Mohorovičić discontinuity or Moho. The cause of the Moho is thought to be a change in rock composition from rocks containing plagioclase feldspar (above) to rocks that contain no feldspars (below). Second, in oceanic crust, there is a chemical discontinuity between ultramafic cumulates and tectonized harzburgites, which has been observed from deep parts of the oceanic crust that have been

neg: Structure of the Earth the crust, upper mantle, lower mantle, outer core, and inner core. The geologic component layers of Earth are at the following depths below the surface: The layering of Earth has been inferred indirectly using the time of travel of refracted and reflected seismic waves created by earthquakes. The core does not allow shear waves to pass through it, while the speed of travel (seismic velocity) is different in other layers. The changes in seismic velocity between different layers causes refraction owing to Snell's law, like light bending as it passes through a prism. Likewise, reflections are caused by a large

neg: Geothermal gradient conduction, as within the rigid tectonic plates, to convection, in the portion of Earth's mantle that convects. Despite its solidity, most of the Earth's mantle behaves over long time-scales as a fluid, and heat is transported by advection, or material transport. Second, radioactive heat production is concentrated within the crust of the Earth, and particularly within the upper part of the crust, as concentrations of uranium, thorium, and potassium are highest there: these three elements are the main producers of radioactive heat within the Earth. Thus, the geothermal gradient within the bulk of Earth's mantle is of the order of

neg: Lithosphere of these xenoliths have been investigated by many methods, including analyses of abundances of isotopes of osmium and rhenium. Such studies have confirmed that mantle lithospheres below some cratons have persisted for periods in excess of 3 billion years, despite the mantle flow that accompanies plate tectonics. Lithosphere A lithosphere ( ["lithos"] for "rocky", and ["sphaira"] for "sphere") is the rigid, outermost shell of a terrestrial-type planet, or natural satellite, that is defined by its rigid mechanical properties. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of

neg: Mantle (geology) Mantle (geology) The mantle is a layer inside a planetary body bounded below by a core and above by a crust. Mantles are made of rock or ices, and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone differentiation by density. All terrestrial planets (including Earth), a number of asteroids, and some planetary moons have mantles. The Earth's mantle is a layer of silicate rock between the crust and the outer core. Its mass of 4.01 × 10 kg is 67% the mass of the Earth. It has

neg: Earth's crustal evolution crust, increasing the difficulty in determining its nature. Recycling of existing primordial crust contributes to the production of secondary crust. Partial melting of the existing crust increases the mafic content of the melt producing basaltic secondary crust. A further method of formation due to the decay of radioactive elements within the Earth releasing heat energy and eventually causing the partial melting of upper mantle, also producing basaltic lavas. As a result, most secondary crust on Earth is formed at mid ocean ridges forming the oceanic crust. The present day continental crust is an example of a tertiary crust. Tertiary crust

neg: Earth science is known as plate tectonics. Plate tectonics might be thought of as the process by which the Earth is resurfaced. As the result of seafloor spreading, new crust and lithosphere is created by the flow of magma from the mantle to the near surface, through fissures, where it cools and solidifies. Through subduction, oceanic crust and lithosphere returns to the convecting mantle. Areas of the crust where new crust is created are called "divergent boundaries", those where it is brought back into the Earth are "convergent boundaries" and those where plates slide past each other, but no new lithospheric material

neg: Lower oceanic crust Lower oceanic crust The lower oceanic crust is the lower part of the oceanic crust and represents the major part of it (volumetrically biggest part). It is generally located 4–8 km below the ocean floor and the major lithologies are mafic (ultramafic and gabbroic rocks) which derive from melts rising from the earth's mantle. This part of the oceanic crust is an important zone for processes such as melt accumulation and melt modification (fractional crystallisation and crustal assimilation). And the recycling of this part of the oceanic crust, together with the upper mantle has been suggested as a significant source

neg: The Lizard atmosphere and extreme southerly location being uniquely suitable. This became the Goonhilly satellite earth station, now owned by Goonhilly Earth Station Ltd. Some important developments in television satellite transmission were made at Goonhilly station. A wind farm exists near to the Goonhilly station site. Known as the Lizard complex, the peninsula's geology is the best preserved example of an exposed ophiolite in the United Kingdom. An ophiolite is a suite of geological formations which represent a slice through a section of ocean crust (including the upper level of the mantle) thrust onto the continental crust. The Lizard formations comprise three

neg: Provenance (geology) Variation of Nd/Nd is caused by decay of Sm. Now Sm/Nd rato of the mantle is higher than that of the crust and Nd/Nd ratio is also higher than in the mantle than in the crust. Nd/Nd ratio is expressed in εNd notation (DePaolo and Wasserbur 1976). formula_1. CHUR refer to Chondritic Uniform Reservoir. So ϵNd is a function of T (time). Nd isotope evolution in mantle and crust in shown in the figure to the right. The upper plot (a), bold line shows the evolution of the bulk earth or CHUR(chondritic uniform reservoir). The lower plot (b) shows evolution

neg: Geography of Newfoundland and Labrador million years ago the action of these plates forced parts of the oceanic crust beneath the Iapetus Ocean up and over the eastern margin of the North American plate. Sections of oceanic crust which overlie continental crust are known as ophiolites. Gros Morne National Park was designated a UNESCO World Heritage Site because it is one of the best places in the world to see the effects of plate tectonics and one of the few places where rocks formed at the Mohorovicic Discontinuity between the crust and the upper mantle of the Earth can be seen. Another notable geology site

neg: Structure of the Earth easily than does the upper mantle (chemical changes within the mantle may also be important). The viscosity of the mantle ranges between 10 and 10 Pa·s, depending on depth. In comparison, the viscosity of water is approximately 10 Pa·s and that of pitch is 10 Pa·s. The source of heat that drives plate tectonics is the primordial heat left over from the planet’s formation as well as the radioactive decay of uranium, thorium, and potassium in Earth’s crust and mantle. The average density of Earth is . Because the average density of surface material is only around , we must

neg: Location hypotheses of Atlantis in Rand's work with author Colin Wilson, in "The Atlantis Blueprint" (published in 2002). The second work theorized that Atlantis was to be found in Lesser Antarctica, near the coast of the Ross Ice Shelf. A geological theory known as "Earth Crust Displacement" forms the basis of their work. The Atlantis Blueprint uses both scientific and pseudoscientific (such as mere speculation and assumptions) means to back up the theory. Charles Hapgood came up with the "Earth Crustal Displacement theory". Hapgood's theory suggests that Earth's outer crust is able to move upon the upper mantle layer rapidly up to a distance

neg: Crustal recycling has been subducted. After a rock has moved to the surface of the earth from beneath the crust, that rock can be sampled for its stable isotopic composition. It can then be compared to known crustal and mantle isotopic compositions, as well as that of chondrites, which are understood to represent original material from the formation of the solar system in a largely unaltered state. One group of researchers was able to estimate that between 5 and 10% of the upper mantle is composed of recycled crustal material. Kokfelt et al. completed an isotopic examination of the mantle plume under

neg: Metal rhodium, palladium, osmium, iridium, and platinum), germanium, and tin—can be counted as siderophiles but only in terms of their primary occurrence in the Earth (core, mantle and crust), rather the crust. These metals otherwise occur in the crust, in small quantities, chiefly as chalcophiles (less so in their native form). The rotating fluid outer core of the Earth's interior, which is composed mostly of iron, is thought to be the source of Earth's protective magnetic field. The core lies above Earth's solid inner core and below its mantle. If it could be rearranged into a column having a 5m footprint

neg: Lithosphere Lithosphere A lithosphere ( ["lithos"] for "rocky", and ["sphaira"] for "sphere") is the rigid, outermost shell of a terrestrial-type planet, or natural satellite, that is defined by its rigid mechanical properties. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater. The outermost shell of a rocky planet, the crust, is defined on the basis of its chemistry and mineralogy. The study of past and current formations of landscapes is called geomorphology. Earth's lithosphere includes the crust and the uppermost mantle, which constitute

neg: Crust (geology) Mars comprise secondary crust, as do the lunar maria. On Earth, we see secondary crust forming primarily at mid-ocean spreading centers, where the adiabatic rise of mantle causes partial melting. Tertiary crust is more chemically-modified than either primary or secondary. It can form in several ways: The only known example of tertiary crust is the continental crust of the Earth. It is unknown whether other terrestrial planets can be said to have tertiary crust, though the evidence so far suggests that they do not. This is likely because plate tectonics is needed to create tertiary crust, and Earth is the

neg: Sea is composed of the Earth's rocky crust and the deeper mostly solid outer layer of the mantle. On land the crust is known as the continental crust while under the sea it is known as the oceanic crust. The latter is composed of relatively dense basalt and is some five to ten kilometres (three to six miles) thick. The relatively thin lithosphere floats on the weaker and hotter mantle below and is fractured into a number of tectonic plates. In mid-ocean, magma is constantly being thrust through the seabed between adjoining plates to form mid-oceanic ridges and here convection currents

neg: Lithosphere 50–140 km thick (but beneath the mid-ocean ridges is no thicker than the crust), while continental lithosphere has a range in thickness from about 40 km to perhaps 280 km; the upper ~30 to ~50 km of typical continental lithosphere is crust. The mantle part of the lithosphere consists largely of peridotite. The crust is distinguished from the upper mantle by the change in chemical composition that takes place at the Moho discontinuity. Oceanic lithosphere consists mainly of mafic crust and ultramafic mantle (peridotite) and is denser than continental lithosphere, for which the mantle is associated with crust made of

neg: Mantle (geology) Pa·s, depending on depth, temperature, composition, state of stress, and numerous other factors. Thus, the upper mantle can only flow very slowly. However, when large forces are applied to the uppermost mantle it can become weaker, and this effect is thought to be important in allowing the formation of tectonic plate boundaries. Exploration of the mantle is generally conducted at the seabed rather than on land because of the relative thinness of the oceanic crust as compared to the significantly thicker continental crust. The first attempt at mantle exploration, known as Project Mohole, was abandoned in 1966 after repeated failures

neg: Near side of the Moon hemisphere crust and upper mantle was hotter than that of the far side, resulting in the larger impact craters. These larger impact craters make up the Man in the Moon references from popular mythology. Near side of the Moon The near side of the Moon is the lunar hemisphere that is permanently turned towards Earth, whereas the opposite side is the far side. Only one side of the Moon is visible from Earth because the Moon rotates on its axis at the same rate that the Moon orbits the Earth – a situation known as synchronous rotation, or tidal locking.

neg: Abyssal plain typically in the abyssal zone, at depths from 3000 to 6000 metres. The table below illustrates the classification of oceanic zones: Oceanic crust, which forms the bedrock of abyssal plains, is continuously being created at mid-ocean ridges (a type of divergent boundary) by a process known as decompression melting. Plume-related decompression melting of solid mantle is responsible for creating ocean islands like the Hawaiian islands, as well as the ocean crust at mid-ocean ridges. This phenomenon is also the most common explanation for flood basalts and oceanic plateaus (two types of large igneous provinces). Decompression melting occurs when the upper

neg: Potrillo volcanic field Rio Grande rifting. More evidence showing this rock contact and with melt deep in the mantle is that primary mantle carbonates are present in many of the pyroxenites found in the Rio Grande Rift magmas or primary melt compositions that crystallized in the upper mantle. Recently, velocity data was acquired using both reflected and refracted arrivals. This data has shown that the upper 5 km of the crust beneath the Portillo volcanic field (PVF) is characterized by alternating regions of low and high velocities of 2.5-3.7 km/s and 3.5-4.3 km/s, respectively. The velocities increase with depth to approximately 6.0 km/s

neg: Delamination (geology) buoyancy of the lower continental crust and mantle lithosphere drive delamination. Delamination occurs when the lower continental crust and mantle lithosphere break away from the upper continental crust. There are two conditions that need to be met in order for delamination to proceed: The metamorphic transition from mafic granulite facies to the denser eclogite facies in the lower portion of the crust is the main mechanism responsible for creating negative buoyancy of the lower lithosphere. The lower crust undergoes a density inversion, causing it to break off of the upper crust and sink into the mantle. Density inversions are more

neg: Mantle (geology) are also sampled as xenoliths within basalts or kimberlites. Most estimates of the mantle composition are based on rocks that sample only the uppermost mantle. There is debate as to whether the rest of the mantle, especially the lower mantle, has the same bulk composition. The mantle's composition has changed through the Earth's history due to the extraction of magma that solidified to form oceanic crust and continental crust. In the mantle, temperatures range from approximately at the upper boundary with the crust to approximately at the core-mantle boundary. The geothermal gradient of the mantle increases rapidly in the thermal

neg: Planetary differentiation dome-shaped forms called diapirs when doing so. On Earth, salt domes are salt diapirs in the crust which rise through surrounding rock. Diapirs of molten low-density silicate rocks such as granite are abundant in the Earth's upper crust. The hydrated, low-density serpentinite formed by alteration of mantle material at subduction zones can also rise to the surface as diapirs. Other materials do likewise: a low-temperature, near-surface example is provided by mud volcanos. On the Moon, a distinctive basaltic material has been found that is high in "incompatible elements" such as potassium, rare earth elements, and phosphorus and is often referred

neg: Crust (geology) enriched compared to the underlying mantle. Although the continental crust comprises only about 0.6 weight percent of the silicate on Earth, it contains 20% to 70% of the incompatible elements. 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 and 2.74 g/cm and for lower crust between 3.0 and 3.25 g/cm. Earth formed approximately 4.6 billion years ago from a disk of dust and gas orbiting the newly formed Sun. It formed via accretion, where planetesimals and other smaller rocky bodies

neg: Oceanic crust crust with laboratory determinations of seismic velocities in known rock types, and samples recovered from the ocean floor by submersibles, dredging (especially from ridge crests and fracture zones) and drilling. Oceanic crust is significantly simpler than continental crust and generally can be divided in three layers. According to mineral physics experiments, at lower mantle pressures, oceanic crust becomes denser than the surrounding mantle. The most voluminous volcanic rocks of the ocean floor are the mid-oceanic ridge basalts, which are derived from low-potassium tholeiitic magmas. These rocks have low concentrations of large ion lithophile elements (LILE), light rare earth elements (LREE),

neg: Lower oceanic crust component for tholeiitic magmas in Hawaiian volcanoes. Although the lower oceanic crust builds the link between the mantle and the MORB, and can’t be neglected for the understanding of MORB evolution, the complex processes operating in this zone remain unclear and there is an ongoing debate in Earth Sciences about this. The lower oceanic crust connects the earth's mantle with the MORB, where around 60% of the total magma production of the Earth happens. The three main processes happening in this region of the oceanic crust are partial melting of the earth's mantle, melt accumulation at various depths and the

neg: Volcanic passive margin cooling and subsidence begins as the margins give way to formation of normal oceanic crust from the widening rifts. Despite the differences in origin and formation, most VPMs share the same characteristics: The active rift model sees rupture driven by hotspot or mantle plume activity. Upwellings of hot mantle, known as mantle plumes, originate deep in Earth and rise to heat and thin the lithosphere. Heated lithosphere thins, weakens, rises, and finally rifts, Enhanced melting following continental breakup is very important in VPMs, creating thicker than normal oceanic crust of 20 to 40 km thick. Other melts caused by convection

neg: Deep crustal hot zone Deep crustal hot zone The Deep Crustal Hot Zone (DCHZ) is a zone in the lower crust where hot mantle material intrudes. In a volcanic arc setting, hot, molten material from the mantle may intrude the lower crust. This hot material generates a new, more evolved melt in this area of the crust, which may collect and migrate upwards towards the upper crust. Here, it would collect in a magma chamber and later erupt. The upper crust consists mainly of evolved, intermediate to silicic magmatic rocks. These rocks may form from either differentiation of primary, mantle-derived magma, or from partial

neg: Earth's internal heat budget primordial heat, respectively. The structure of the Earth is a rigid outer crust that is composed of thicker continental crust and thinner oceanic crust, solid but plastically flowing mantle, a liquid outer core, and a solid inner core. The fluidity of a material is proportional to temperature; thus, the solid mantle can still flow on long time scales, as a function of its temperature and therefore as a function of the flow of Earth's internal heat. The mantle convects in response to heat escaping from Earth's interior, with hotter and more buoyant mantle rising and cooler, and therefore denser, mantle

neg: Crust (geology) Crust (geology) In geology, the crust is the outermost solid shell of a rocky planet, dwarf planet, or natural satellite. It is usually distinguished from the underlying mantle by its chemical makeup; however, in the case of icy satellites, it may be distinguished based on its phase (solid crust vs. liquid mantle). The crusts of Earth, Moon, Mercury, Venus, Mars, Io, and other planetary bodies formed via igneous processes, and were later modified by erosion, impact cratering, volcanism, and sedimentation. Most terrestrial planets have fairly uniform crusts. Earth, however, has two distinct types: continental crust and oceanic crust. These two

neg: Volcano Volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle. Therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-oceanic ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has

neg: Basin and range topography Basin and range topography Basin and range topography is an alternating landscape of parallel mountain ranges and valleys. It is a result of crustal extension/stretching (extensional tectonics) of the lithosphere (crust and upper mantle) due to mantle upwelling, gravitational collapse, crustal thickening, or relaxation of confining stresses. Crustal extension causes the thinning and deformation of the upper crust in an orientation perpendicular to the direction of extension. As the plates pull apart, they thin allowing the hot mantle to rise close to the surface. When the crust is extended it fractures along a fault plane, creating a series of long

neg: Primitive mantle Primitive mantle The primitive mantle is, in geochemistry, a hypothetical reservoir with the composition of the Earth's crust and mantle taken together. The currently accepted scientific hypothesis is that the Earth was formed by accretion of material with a chondritic composition. Still during the accretionary phase planetary differentiation started, giving rise to the Earth's core, where heavy metallic siderophile elements accumulated. Around it was a (in this stage) undifferentiated mantle, the primitive mantle. Further differentiation would take place later, creating the different chemical reservoirs of crust and mantle, with incompatible elements accumulating in the crust. Today differentiation still continues in

neg: Mid-ocean ridge oceanic spreading centers. Mid-ocean ridge basalt is a tholeiitic basalt and is characteristically low in incompatible elements. The rocks making up the crust below the seafloor are youngest along the axis of the ridge and age with increasing distance from that axis. New magma of basalt composition emerges at and near the axis because of decompression melting in the underlying Earth's mantle. The oceanic crust is made up of rocks much younger than the Earth itself. Most oceanic crust in the ocean basins is less than 200 million years old. The crust is in a constant state of "renewal" at

neg: Andrija Mohorovičić seismic waves change speed and the difference in chemical composition between rocks from the crust and those from the mantle. From the data, he estimated the thickness of the upper layer (crust) to be 54 km. We know today that the crust is 5–9 km below the ocean floor and 25–60 km below the continents, which are carried on tectonic plates. Subsequent study of the Earth's interior confirmed the existence of the discontinuity under all continents and oceans. Mohorovičić assumed that the velocity of seismic waves increases with the depth. The function he proposed to calculate the velocity of seismic

neg: Subcontinental lithospheric mantle relative to MORB (which samples modern upper mantle) and have been sampled by Re-Os isotope dating of peridotites and ophiolites. The trace element composition of these xenoliths suggest mixing between the two different layers of subcontinental mantle. Particularly, the theory for the removal of Archean subcontinental lithosphere below Archean continental crust via delamination helps to explain mantle-peridotite xenoliths found in the extinct Sierra Nevada arc. Though there is evidence for the preservation of the Archean lithosphere, there is controversy over the preservation of the Archean mantle, for which the Archean lithosphere would have been derived. The formation of the Archean

neg: Offshore Indus Basin coeval pelagic sediment was deposited in the intervening structural lows. As the Indian plate drifted northwards away from the Reunion mantle hotspot, the basin subsided rapidly. This was accompanied by major clastic influx from the Indus river and leading to deposition of up to 9 km of Oligocene to Recent sediments. Seismic and gravity data suggest that the underlying crust in the offshore Indus basin is of three types: continental, transitional and oceanic. Continental crust is interpreted for the area below the shelf and upper slope based on the presence of deep rift geometries on seismic lines. Transitional crust occurs

neg: Crust (geology) magma ocean and floated to the top; however, it is unlikely that Earth followed a similar pattern, as the Moon was a water-less system and Earth had water. The Martian meteorite ALH84001 might represent primary crust of Mars; however, again, this is debated. Like Earth, Venus lacks primary crust, as the entire planet has been repeatedly resurfaced and modified. Secondary crust is formed by partial melting of silicate materials in the mantle, and so is usually basaltic in composition. This is the most common type of crust in the Solar System. Most of the surfaces of Mercury, Venus, Earth, and

neg: Harzburgite Harzburgite may also be found in some Alpine peridotite massifs that consist mostly of lherzolite. Alpine or orogenic lherzolites represent subcontinental mantle lithosphere (the upper mantle below continental crust) exposed during the plate tectonic collision of continental plates. Examples of orogenic lherzolite massifs with harzburgite include the Lherz Massif in France (Pyrenees Mountains), the Lanzo Massif in northern Italy, and the Horoman Massif in Japan. Garnet-bearing harzburgite is found as xenoliths in some kimberlite pipes, which are found almost exclusively in ancient continental cratons of Archean or Paleoproterozoic age. The mantle lithosphere under these cratons is particularly thick (up to

neg: Geochemical cycle As all closed systems, it follows the law of conservation of mass which states that matter cannot be created nor destroyed, thus, the matter, although transformed and migrated, remains the same as when the Earth was formed. The Earth system contains seven different reservoirs that are separated into surface reservoirs, which include atmosphere, hydrosphere, biosphere, pedosphere, and lithosphere and the isolated reservoirs that include deep Earth and outer space. Geochemical cycles are concerned with the interactions between deep earth which consists of Earth´s mantle and core, and the lithosphere which consists of the Earth´s crust. Flux in geochemical cycles is

neg: Structure of the Earth known as the D″ ( dee-double-prime) layer. The pressure at the bottom of the mantle is ≈140 GPa (1.4 Matm). The mantle is composed of silicate rocks that are rich in iron and magnesium relative to the overlying crust. Although solid, the high temperatures within the mantle cause the silicate material to be sufficiently ductile that it can flow on very long timescales. Convection of the mantle is expressed at the surface through the motions of tectonic plates. As there is intense and increasing pressure as one travels deeper into the mantle, the lower part of the mantle flows less

neg: Oceanic crust Oceanic crust Oceanic crust is the uppermost layer of the oceanic portion of a tectonic plate. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumulates. The crust overlies the solidified and uppermost layer of the mantle. The crust and the solid mantle layer together constitute oceanic lithosphere. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium. It is thinner than continental crust, or sial, generally less than 10 kilometers thick; however it is denser,

neg: Oceanic crust continuously being created at mid-ocean ridges. As plates diverge at these ridges, magma rises into the upper mantle and crust. As it moves away from the ridge, the lithosphere becomes cooler and denser, and sediment gradually builds on top of it. The youngest oceanic lithosphere is at the oceanic ridges, and it gets progressively older away from the ridges. As the mantle rises it cools and melts, as the pressure decreases and it crosses the solidus. The amount of melt produced depends only on the temperature of the mantle as it rises. Hence most oceanic crust is the same thickness

neg: Crust (geology) centers, where partial-melting of the underlying mantle yields basaltic magmas and new ocean crust forms. This "ridge push" is one of the driving forces of plate tectonics, and it is constantly creating new ocean crust. That means that old crust must be destroyed somewhere, so, opposite a spreading center, there is usually a subduction zone: a trench where an ocean plate is being shoved back into the mantle. This constant process of creating new ocean crust and destroying old ocean crust means that the oldest ocean crust on Earth today is only about 200 million years old. In contrast, the

neg: Eustatic sea level ocean basin can gradually grow or shrink from GIA. GIA occurs from major glaciations or melts. When a continent experiences mass glaciations, a significant weight is pressed upon the continental crust which ‘floats’ on the upper mantle. This portion of the upper mantle moves like plastic, so the weighted crust will sink. Thus, the ocean basin itself will shrink. Vice versa, when ice sheet runoff occurs, the weight on the crust is relieved causing rise of continental crust . This will effectively increase the size of the ocean basin. 3. Density changes of the water (thermal expansion) • Greenhouse gases

neg: Kynance Cove park. Much of the Lizard peninsula is known for its botany and geology, and about 375 million years ago the molten rock, which eventually became the Lizard, was about 10 km below the surface of the earth and under immense heat and pressure. One of the rocks (peridotite) is rich in magnesium and iron, and changed through heat and pressure to serpentinite as it pushed upwards from the Moho, the boundary of the earth's crust and mantle. It finally reached the crust's surface, about 30° south of the equator as part of an ocean ridge, in the Rheic Ocean. Over

neg: Volcano were proposed for volcano behavior before the modern understanding of the Earth's mantle structure as a semisolid material was developed. For decades after awareness that compression and radioactive materials may be heat sources, their contributions were specifically discounted. Volcanic action was often attributed to chemical reactions and a thin layer of molten rock near the surface. Volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Earth's volcanoes occur because its crust is broken into 17 major,

neg: Earth's internal heat budget Earth's internal heat loss at the surface is by conduction through the crust, and mantle convection is the dominant control on heat transport from deep within the Earth. Most of the heat flow from the thicker continental crust is attributed to internal radiogenic sources, in contrast the thinner oceanic crust has only 2% internal radiogenic heat. The remaining heat flow at the surface would be due to basal heating of the crust from mantle convection. Heat fluxes are negatively correlated with rock age, with the highest heat fluxes from the youngest rock at mid-ocean ridge spreading centers (zones of mantle

neg: Supercontinent "superplumes". When a slab of subducted crust is denser than the surrounding mantle, it sinks to the discontinuity. Once the slabs build up, they will sink through to the lower mantle in what is known as a "slab avalanche". This displacement at the discontinuity will cause the lower mantle to compensate and rise elsewhere. The rising mantle can form a plume or superplume. Besides having compositional effects on the upper mantle by replenishing the large-ion lithophile elements, volcanism affects plate movement. The plates will be moved towards a geoidal low perhaps where the slab avalanche occurred and pushed away from

neg: Subduction additional negative buoyancy (downwards force). It is at subduction zones that Earth's lithosphere, oceanic crust and continental crust, sedimentary layers and some trapped water are recycled into the deep mantle. Earth is so far the only planet where subduction is known to occur. Subduction is the driving force behind plate tectonics, and without it, plate tectonics could not occur. Oceanic subduction zones dive down into the mantle beneath 55,000 kilometers of convergent plate margins (Lallemand, 1999), almost equal to the cumulative 60,000 kilometers of mid-ocean ridges. Subduction zones burrow deeply, but are imperfectly camouflaged, and geophysics and geochemistry can be

neg: Craton complex synforms between rising young domiform felsic batholiths mobilized by hydrous partial melting in the lower crust. Upper-crust granite-and-greenstone terrains underwent moderate regional shortening, decoupled from the lower crust, during compositional inversion accompanying doming, but cratonization soon followed. Tonalitic basement is preserved beneath some greenstone sections but supracrustal rocks commonly give way downward to correlative or younger plutonic rocks... Mantle plumes probably did not yet exist, and developing continents were concentrated in cool regions. Hot-region upper mantle was partly molten, and voluminous magmas, mostly ultramafic, erupted through many ephemeral submarine vents and rifts focussed at the thinnest crust... Surviving Archean

neg: Apennine Mountains across inland north Africa. The upper mantle above deep is broken into the "Northern Apennines Arc" and the "Calabrian Arc", with compressional forces acting in different directions radially toward the arcs' centers of curvature. The overall plate tectonics of these events has been modeled in different ways but decisive data is still missing. The tectonics, however, are not the same as those which created the Alps. The west side of Italy is given to a fault-block system, where the crust, extended by the lengthening mantle below, thinned, broke along roughly parallel fault lines, and the blocks alternatively sank into grabens

neg: Intraplate deformation Intraplate deformation Intraplate deformation is the folding, breaking, or flow of the Earth's crust within plates instead of at their margins. This process usually occurs in areas with especially weak crust and upper mantle, such as the Tibetan Plateau (Figure 1). Intraplate deformation brings another aspect to plate tectonic theory. The theory of plate tectonics states that the Earth's crust is made up of rigid plates that "float" on top of the mantle and move relative to one another. As the plates move, the crust deforms dominantly along the plate margins. Intraplate deformation differs from that respect by the observation

neg: Subduction and define the Wadati–Benioff zone. Seismicity shows that the slab can be tracked down to the upper mantle/lower mantle boundary (approximately six hundred kilometer depth). Nine of the ten largest earthquakes of the last 100 years were subduction zone events, which included the 1960 Great Chilean earthquake, which, at M 9.5, was the largest earthquake ever recorded; the 2004 Indian Ocean earthquake and tsunami; and the 2011 Tōhoku earthquake and tsunami. The subduction of cold oceanic crust into the mantle depresses the local geothermal gradient and causes a larger portion of Earth to deform in a more brittle fashion than

neg: Gakkel Ridge from the mantle, below the crust, which is very unusual for a mid-ocean ridge . It confirms that the mantle and crust of Gakkel ridge, like some segments of the Southwest Indian Ridge, are very cold. Gakkel Ridge The Gakkel Ridge (formerly known as the Nansen Cordillera and Arctic Mid-Ocean Ridge) is a mid-oceanic ridge, a divergent tectonic plate boundary between the North American Plate and the Eurasian Plate. It is located in the Eurasian Basin of the Arctic Ocean, between Greenland and Siberia, and has a length of about 1,800 kilometers. Geologically, it connects the northern end of the

neg: Volcanology of Canada more than in a mantle plume environment beneath the North American lithosphere. As the mantle plume intruded rocks of the Canadian Shield, it created an upwelling zone of molten rock known as the Mackenzie hotspot. Upper lavas were partly contaminated with crustal rocks as magmas from the mantle plume passed through the lower and upper crust. During the Early Jurassic period 196 million years ago, the New England or Great Meteor hotspot existed in the Rankin Inlet area of southern Nunavut along the northwestern coast of Hudson Bay, producing kimberlite magmas. This marks the first appearance of the New England

neg: Basin and Range Province of crust and upper mantle. Extensional environments like the Basin and Range are characterized by listric normal faulting, or faults that level out with depth. Opposing normal faults link at depth producing a horst and graben geometry, where horst refers to the upthrown fault block and graben to the down dropped fault block. The average crustal thickness of the Basin and Range Province is approximately 30 – 35 km and is comparable to extended continental crust around the world. The crust in conjunction with the upper mantle comprises the lithosphere. The base of the lithosphere beneath the Basin and Range

neg: Divergent double subduction subduction of the plate because the mantle material below the plate is trapped. The dense oceanic plate has a high tendency to sink. As it sinks, it breaks along the oceanic plate and the welded crust above and a gap is created. The extra space created leads to the decompression melting of mantle wedge materials. The melts flow upward and fill the gap and intrude the oceanic plate and welded crust as mafic dykes intrusion. Eventually, the oceanic plate completely breaks apart from the welded crust as it continues to sink. When the oceanic plate breaks apart from the crust

neg: Non-volcanic passive margins transition. The crust, as well as the entire lithosphere, is thinned due to mechanical extension. The Moho marks a large density contrast between crust and mantle, typically at least 0.35 g/cm3. The highest amplitudes of the gravity anomaly occur seaward of the continent-ocean transition. High-density upper mantle material is elevated relative to the more landward crustal root. The oceanic crust density is then further enhanced with gabbros and basalts and additionally contributes to the regional gravity trend. Where the thickness of the crust and lithosphere varies, equilibrium must be reached. Isostatic compensation and gravity anomalies result from balance between mass

neg: Crust (geology) 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. Crust (geology) In geology, the crust is the outermost solid shell of a rocky planet, dwarf planet, or natural satellite. It is usually distinguished from the underlying mantle by its chemical makeup; however, in the case of icy satellites, it may be distinguished based on its phase (solid crust vs. liquid mantle). The crusts of Earth, Moon, Mercury, Venus, Mars,

neg: Obduction rocks that have been emplaced onto a continent. This assemblage consists of deep-marine sedimentary rock (chert, limestone, clastic sediments), volcanic rocks (pillow lavas, glass, ash, sheeted dykes and gabbros) and peridotite (mantle rock). This process is operative beneath and behind the inner walls of oceanic trenches (subduction zone) where slices of oceanic crust and mantle are ripped from the upper part of the descending plate and wedged and packed in high pressure assemblages against the leading edge of the other plate. Weakening and cracking of oceanic crust and upper mantle is likely to occur in the tensional regime. This results

neg: Mantle (geology) for later in 2007. The Chikyu Hakken mission attempted to use the Japanese vessel "Chikyū" to drill up to below the seabed. This is nearly three times as deep as preceding oceanic drillings. A novel method of exploring the uppermost few hundred kilometres of the Earth was proposed in 2005, consisting of a small, dense, heat-generating probe which melts its way down through the crust and mantle while its position and progress are tracked by acoustic signals generated in the rocks. The probe consists of an outer sphere of tungsten about one metre in diameter with a cobalt-60 interior acting

neg: Geothermal gradient and 101 mW/m over oceanic crust. This is 0.087 watt/square meter on average (0.03 percent of solar power absorbed by the Earth ), but is much more concentrated in areas where the lithosphere is thin, such as along mid-ocean ridges (where new oceanic lithosphere is created) and near mantle plumes. The Earth's crust effectively acts as a thick insulating blanket which must be pierced by fluid conduits (of magma, water or other) in order to release the heat underneath. More of the heat in the Earth is lost through plate tectonics, by mantle upwelling associated with mid-ocean ridges. The final

neg: Origin of the Moon 1925 also suggested the emerging of the Moon as cause for continental drift. It was proposed that the Pacific Ocean represented the scar of this event. Today it is known that the oceanic crust that makes up this ocean basin is relatively young, about 200 million years old or less, whereas the Moon is much older. The Moon does not consist of oceanic crust but of mantle material, which originated inside the proto-Earth in the Precambrian. The hypothesis of accretion suggests that the Earth and the Moon formed together as a double system from the primordial accretion disk of the

neg: Earth science as rocks or river water), then they record their findings on charts and maps. The following fields of science are generally categorized within the Earth sciences: Plate tectonics, mountain ranges, volcanoes, and earthquakes are geological phenomena that can be explained in terms of physical and chemical processes in the Earth's crust. Beneath the Earth's crust lies the mantle which is heated by the radioactive decay of heavy elements. The mantle is not quite solid and consists of magma which is in a state of semi-perpetual convection. This convection process causes the lithospheric plates to move, albeit slowly. The resulting process

neg: Rhenium–osmium dating oceanic crust (which is derived from partial melting of mantle) and low ratios of Re/Os in the lower mantle. In this regard, the Re–Os system to study the geochemical evolution of mantle rocks and in defining the chronology of mantle differentiation is extremely helpful. Peridotite xenoliths which are thought to sample the upper mantle sometimes contain supra-chondritic Os-isotopic ratios. This is thought to evidence of subducted ancient high Re/Os basaltic crust that is being recycled back into the mantle. This combination of radiogenic (Os that was created by decay of Re) and nonradiogenic melts helps to support the theory of

neg: Archean subduction Earth being 200 K hotter in the Archean than it is today. Assuming seafloor spreading generated oceanic lithosphere in the Archean, higher temperatures led to greater melting of mantle material rising at oceanic spreading centres. This in turn produced thicker oceanic crust and thicker regions of underlying depleted lithospheric mantle. As such, the density of the lithosphere was reduced due to both differentiation of the crust from the mantle and the ensuing relative depletion of the residual mantle in Fe and Al. These expected properties have led to suggestions that oceanic lithosphere was so light that it subducted very shallowly

neg: Moon atop. The final liquids to crystallise would have been initially sandwiched between the crust and mantle, with a high abundance of incompatible and heat-producing elements. Consistent with this perspective, geochemical mapping made from orbit suggests the crust of mostly anorthosite. The Moon rock samples of the flood lavas that erupted onto the surface from partial melting in the mantle confirm the mafic mantle composition, which is more iron-rich than that of Earth. The crust is on average about thick. The Moon is the second-densest satellite in the Solar System, after Io. However, the inner core of the Moon is small,

neg: Divergent double subduction dacite and tuff. These arc volcanic rocks are enriched in Large Ion Lithophile Element (LILE) and Light Rare Earth Element (LREE) but depleted in niobium, hafnium and titanium. Partial melting of mantle generate mafic dykes intrusion. Because the mantle is the primary source, these dykes record isotopic characteristics of the depleted mantle in which the Sr/Sr ratio is near 0.703 and εNd is positive. On the other hand, partial melting of the lower crust (accretionary complex) leads to S-type granitoids intrusion with enriched aluminum oxide throughout the evolution of divergent double subduction. When the oceanic plate detaches from the overlying

neg: Abundance of the chemical elements have larger ionic radii) and therefore more strongly concentrated in the continental crust than the heavier rare earth elements. In most rare earth ore deposits, the first four rare earth elements – lanthanum, cerium, praseodymium, and neodymium – constitute 80% to 99% of the total amount of rare earth metal that can be found in the ore. The mass-abundance of the eight most abundant elements in the Earth's mantle (see main article above) is approximately: oxygen 45%, magnesium 23%, silicon 22%, iron 5.8%, calcium 2.3%, aluminum 2.2%, sodium 0.3%, potassium 0.3%. The mantle differs in elemental composition from the crust

neg: Peridotite be present in lesser abundance include olivine, garnet, plagioclase, amphibole, and spinel. Peridotite is the dominant rock of the Earth's mantle above a depth of about 400 km; below that depth, olivine is converted to the higher-pressure mineral wadsleyite. Oceanic plates consist of up to about 100 km of peridotite covered by a thin crust; the crust, commonly about 6 km thick, consists of basalt, gabbro, and minor sediments. The peridotite below the ocean crust, "abyssal peridotite," is found on the walls of rifts in the deep sea floor. Oceanic plates are usually subducted back into the mantle in subduction

neg: Seamount Seamount, Eratosthenes Seamount, Axial Seamount and Gorringe Ridge. If all known seamounts were collected into one area, they would make a landform the size of Europe. Their overall abundance makes them one of the most common, and least understood, marine structures and biomes on Earth, a sort of exploratory frontier. Most seamounts are built by one of two volcanic processes, although some, such as the Christmas Island Seamount Province near Australia, are more enigmatic. Volcanoes near plate boundaries and mid-ocean ridges are built by decompression melting of rock in the upper mantle. The lower density magma rises through the crust

neg: Earth chlorine, sulfur, and fluorine are the important exceptions to this and their total amount in any rock is usually much less than 1%. Over 99% of the crust is composed of 11 oxides, principally silica, alumina, iron oxides, lime, magnesia, potash, and soda. Earth's interior, like that of the other terrestrial planets, is divided into layers by their chemical or physical (rheological) properties. The outer layer is a chemically distinct silicate solid crust, which is underlain by a highly viscous solid mantle. The crust is separated from the mantle by the Mohorovičić discontinuity. The thickness of the crust varies from

neg: Volcanology of Northern Canada at a depth of more than in a mantle plume environment beneath the North American lithosphere. As the mantle plume intruded rocks of the Canadian Shield, it created an upwelling zone of molten rock known as the Mackenzie hotspot. Upper lavas were partly contaminated with crustal rocks as magmas from the mantle plume passed through the lower and upper crust. During the Early Jurassic period 196 million years ago, the New England or Great Meteor hotspot existed in the Rankin Inlet area of southern Nunavut along the northwestern coast of Hudson Bay, producing kimberlite magmas. This marks the first appearance

neg: Europa (moon) the subsurface ocean mechanically decoupling Europa's surface from its rocky mantle and the effects of Jupiter's gravity tugging on Europa's outer ice crust. Comparisons of "Voyager" and "Galileo" spacecraft photos serve to put an upper limit on this hypothetical slippage. The full revolution of the outer rigid shell relative to the interior of Europa occurs over a minimum of 12,000 years. Studies of "Voyager" and "Galileo" images have revealed evidence of subduction on Europa's surface, suggesting that, just as the cracks are analogous to ocean ridges, so plates of icy crust analogous to tectonic plates on Earth are recycled into

neg: Back-arc region upper plate and the high heat flow that characterizes back-arcs. The pulling effect of the slab as it goes down into the mantle causes a rollback motion of the trench, which also applies stress on the back-arc region of the upper plate. However, this last process has less of an impact on deformation compared to upper plate motion. Back-arcs can form on either oceanic crust or continental crust. In the case of oceanic crust, most back-arc regions are subjected to tensional stresses and thus develop a spreading center where new oceanic crust is formed. The composition of this new crust

neg: Erosion and tectonics of material is eroded away from the Earth's surface uplift occurs in order to maintain isostatic equilibrium. Because of isostasy, high erosion rates over significant horizontal areas can effectively suck up material from the lower crust and/or upper mantle. This process is known as "isostatic rebound" and is analogous to Earth's response following the removal of large glacial ice sheets. Isostatic uplift and corresponding erosion are responsible for the formation of regional-scale geologic features as well as localized structures. Two such examples include: Channel flow describes the process through which hot, viscous crustal material flows horizontally between the upper crust

neg: Walter D. Mooney Germany, Mooney wrote "Exploring the Earth's Crust - History and Results of Controlled-Source Seismology"). Since 2011, he has been collaborating with the Saudi Geological Survey in a study of the crustal and upper mantle structure beneath western Saudi Arabia using data from the SGS broadband seismic network. Mooney is considered a world leader in geophysical studies of the Earth's crust and upper mantle. In 1995, he was awarded the Geological Society of America's (GSA) George P. Woollard Award. This award is given annually to recognize a person who has made outstanding contributions to geology using geophysical methods. as well as

neg: Mantle plume trace elements, they are typically more enriched in the light rare-earth elements than mid-ocean ridge basalts. Compared to island arc basalts, ocean island basalts are lower in alumina (AlO) and higher in immobile trace elements (e.g., Ti, Nb, Ta). These differences result from processes that occur during the subduction of oceanic crust and mantle lithosphere. Oceanic crust (and to a lesser extent, the underlying mantle) typically becomes hydrated to varying degrees on the seafloor, partly as the result of seafloor weathering, and partly in response to hydrothermal circulation near the mid-ocean-ridge crest where it was originally formed. As oceanic crust

neg: Carbon PAHs seem to have been formed "a couple of billion years" after the Big Bang, are widespread throughout the universe, and are associated with new stars and exoplanets. It has been estimated that the solid earth as a whole contains 730 ppm of carbon, with 2000 ppm in the core and 120 ppm in the combined mantle and crust. Since the mass of the earth is , this would imply 4360 million gigatonnes of carbon. This is much more than the amount of carbon in the oceans or atmosphere (below). In combination with oxygen in carbon dioxide, carbon is found

neg: Geothermal gradient atomic radii such as magnesium (Mg), titanium (Ti), and calcium (Ca). The geothermal gradient is steeper in the lithosphere than in the mantle because the mantle transports heat primarily by convection, leading to a geothermal gradient that is determined by the mantle adiabat, rather than by the conductive heat transfer processes that predominate in the lithosphere, which acts as a thermal boundary layer of the convecting mantle. Heat flows constantly from its sources within the Earth to the surface. Total heat loss from the Earth is estimated at 44.2 TW (). Mean heat flow is 65 mW/m over continental crust

neg: Abundance of the chemical elements in the Sun and outer planets is similar to that in the universe. Due to solar heating, the elements of Earth and the inner rocky planets of the Solar System have undergone an additional depletion of volatile hydrogen, helium, neon, nitrogen, and carbon (which volatilizes as methane). The crust, mantle, and core of the Earth show evidence of chemical segregation plus some sequestration by density. Lighter silicates of aluminum are found in the crust, with more magnesium silicate in the mantle, while metallic iron and nickel compose the core. The abundance of elements in specialized environments, such as atmospheres, or

neg: Christopher Andronicos the University of Texas at El Paso. In 2005 he moved to a position at Cornell University where he was a member of the Institute for the Study of the Continents, and a member of the faculty in the Department of Earth and Atmospheric Sciences and the American Indian Program. In 2012, Andronicos accepted a position as an associate professor at Purdue University in the Department of Earth, Atmospheric, and Planetary Sciences. His research is focused on understanding high temperature deformation in the deep crust and upper mantle. He has focused his work on continental orogenic belts in the southwestern

neg: Geology of New Zealand be slid across were slabs of oceanic crust (ophiolites), mainly basalt. Widespread volcanic activity also occurred (23–15 Ma), and is intermixed with the foreign rocks. Sedimentary basins formed on the allochthons while they were moving. East Cape was later separated from Northland and moved further south and east to its present position. Volcanism is recorded in New Zealand throughout its whole geological history. Most volcanism in New Zealand, both modern and ancient, has been caused by the subduction of one tectonic plate under another, this causes melting in the mantle, the layer of the earth below the crust. This produces

neg: Rare-earth element to alkaline plutonism, an uncommon kind of magmatism that occurs in tectonic settings where there is rifting or that are near subduction zones. In a rift setting, the alkaline magma is produced by very small degrees of partial melting (<1%) of garnet peridotite in the upper mantle (200 to 600 km depth). This melt becomes enriched in incompatible elements, like the rare-earth elements, by leaching them out of the crystalline residue. The resultant magma rises as a diapir, or diatreme, along pre-existing fractures, and can be emplaced deep in the crust, or erupted at the surface. Typical REE enriched deposits