Basalt | Encyclopedia MDPI
Basalt (/bəˈsɔːlt, ˈbæsɒlt, -sɔːlt/) is a mafic extrusive igneous rock formed from the rapid cooling of magnesium-rich and iron-rich lava exposed at or very near the surface of a terrestrial planet or a moon. More than 90% of all volcanic rock on Earth is basalt. Basalt lava has a low viscosity, due to its low silica content, resulting in rapid lava flows that can …Web
اقرأ أكثرElemental and Sr–Nd–Pb isotopic geochemistry of Mesozoic …
Was there Jurassic paleo-Pacific subduction in South China?: Constraints from 40Ar/39Ar dating, elemental and Sr–Nd–Pb isotopic geochemistry of the Mesozoic basalts. Lithos, Vol. 106, Issue. 1-2, p. 83.Web
اقرأ أكثرHainan mantle plume produced late Cenozoic basaltic rocks in
In the plot of Th/Yb versus Ta/Yb for discriminating tectonic setting of basaltic rocks 77, all samples plot in the array of basalts from non-subduction settings (e.g., MORB, and within plate ...Web
اقرأ أكثرIntraplate volcanism originating from upwelling hydrous mantle
The Cenozoic intraplate volcanism in northeast China is located more than 1,000 km westward of the Japan Trench 1, while the young alkaline basalts (0–6 Ma) known as petit-spots outcrop up to ...Web
اقرأ أكثرGeochemistry of a Tertiary continental basalt suite, Red Sea …
The basalts show general trends of increasing incompatible elements (K 2 O, Nb, Y, Sr and Yb), and decreasing contents of compatible elements (Cr, Ni, Sc and Ca) with decreasing Mg no. Furthermore, TiO 2, P 2 O 5, LREE and Th define maxima at about Mg no.=56, suggesting late fractionation of Fe–Ti oxides and apatite.Web
اقرأ أكثرBasalt | Definition, Properties, & Facts | Britannica
Alkali basalts predominate among the lavas of the ocean basins and are common among the mafic lavas of the forelands and …Web
اقرأ أكثرNumerical modelling of CO2-water-basalt interaction
The effects of CO 2 on water-basaltic glass interaction have been simulated at 25ºC. The calculations indicate that addition of CO 2 (2—30 bar) to water significantly changes the reaction path. Initially, the pH is buffered between 4 and 6 by CO 2 ionization, with dissolution of basaltic glass and the formation of secondary minerals with SiO2, Mg …Web
اقرأ أكثرAfghanistan 2001-2021: The skyline and the slum
Afghanistan, a mountainous territory nestled in the heartland of Asia, has long been a battlefield of global powers. But it has never been conquered, and hence …Web
اقرأ أكثرBasalt Definition, Composition & Uses
Basalt rock is made from volcanos, as it forms from lava that rapidly cools above the surface. Basalt is a type of extrusive igneous rock that gets its dark color from the composition of its ...Web
اقرأ أكثرAptian flood basalts in Bacalhau oil and gas field
A post-rift Aptian magmatism is recorded in a 500-m-thick sequence of basalts interbedded with marls in the Bacalhau oil and gas field in Santos Basin, SE Brazil. This magmatic section is within the so-called pre-salt sequence of Santos Basin that comprises the major oil and gas reserves of Brazil. This is the first publication of …Web
اقرأ أكثرThe Deccan Volcanic Province (DVP), India: A Review
Geochemical data (major and minor oxides, trace elements including REE, and Sr, Nd, Pb, and O isotopes) have been obtained on a number of flow sequences and plutonic and volcanic complexes of the DVP by numerous groups since the early 1970's. Evaluation of these data has led to the classification of the basalts and other rock types, …Web
اقرأ أكثرA Guide to Basalt: A Common, Fine-grained, Dark-Colored …
Basalts are usually dark colored, i.e., dark gray, brown-black, greenish-black, or black fine-grained rocks. However, they can have other textures and colors. Also, weathered hand specimens may have a tan, yellow, brown, or reddish-brown surface. Thus, try to get one with a freshly cut surface. 1. ColorsWeb
اقرأ أكثرExperimental Petrology and Petrogenesis of Apollo 12 Basalts
Experimental studies at 1 bar and up to 30 kbar establish the crystallization sequences for basalts 12021, 12065, 12022, 12009 and 12040. Olivine is the liquidus phase at low pressures, with minor chromium spinel and pigeonitic clinopyroxene joining the olivine at lower temperatures or accompanying the olivine in the less magnesian basalts (12021, …Web
اقرأ أكثرAge, geochemical characteristics and petrogenesis of Late …
Miocene to Quaternary alkali basalts in the Lut–Sistan region, eastern Iran are spatially associated with two active, N–S-trending dextral strike–slip fault systems in the region, i.e., the Neh faults in the Sistan suture zone and the Nayband fault ~ 200 km further to the west in the Lut block.Here, we present new 40 Ar/ 39 Ar ages, geochemical and …Web
اقرأ أكثرGeology and petrogenesis of gabbro from the Zhob Ophiolite
Large olistoliths of intra-plate alkali basalts of hotspot affinity (Sawada et al. 1993; Siddiqui et al. 1994) are found within the hyaloclastite in the Muslim Bagh area ... Boulin J (1981) Structure d Afghanistan sutures periindiennes et Tethys orientale. CR Academy of Sci Paris Ser D 292:239–242. Google Scholar Boulin J (1988) Hercynian and ...Web
اقرأ أكثرAfghanistan War | History, Combatants, Facts,
Afghanistan War, international conflict in Afghanistan beginning in 2001 that was triggered by the September 11 attacks and consisted of three phases. The first phase—toppling the Taliban (the …Web
اقرأ أكثرGeochemistry of continental alkali basalts in the Sabzevar region
A geochemical study was undertaken on basaltic lava flows intercalated with Oligocene to Miocene strata in the Sabzevar region, northern Iran, to examine their petrogenesis in a regional tectonic framework. The lavas are either aphyric or have phenocrysts and micro-phenocrysts of olivine and, to a lesser extent, clinopyroxene. …Web
اقرأ أكثرElemental and Sr–Nd isotopic geochemistry of the basalts and
A plagioclase-accumulation model is used to account for the high alumina contents. Moreover, the basalts have enriched MORB (E-MORB) -like trace element characteristics with lower ε Nd (t) values (6.4–8.0) and (87 Sr/ 86 Sr) i ratios (0.7032–0.7036). Their incompatible element ratios exhibit linear correlation with the …Web
اقرأ أكثرGeochemistry of a Tertiary continental basalt suite, Red Sea …
Comparison with the different types of OIB indicates that the basalts may be derived from a high U/Pb (HIMU) source with slightly elevated K and Ba contents. The basalts show general trends of increasing incompatible elements (K 2 O, Nb, Y, Sr and Yb), and decreasing contents of compatible elements (Cr, Ni, Sc and Ca) with decreasing Mg no.Web
اقرأ أكثرA Timeline Of Afghanistan's 4 Decades Of Instability : NPR
The Soviet army in Kabul, Afghanistan, on Dec. 31, 1979. Francois Lochon/Gamma-Rapho/Getty Images. The collapse of the Afghan government and the Taliban's recapture of power came after a blitz by ...Web
اقرأ أكثر6 US Military Bases in Afghanistan | MilitaryBases
There are 6 US military bases in Afghanistan according to our database which is being updated all the time. Learn more about military bases.Web
اقرأ أكثرPetrochemistry and genesis of olivine basalts from small
The basalts have variable 87Sr/86Sr (0.704177–0.705139) and 143Nd/144Nd (0.512689–0.512830) ratios, within the range of OIB-like intra-plate alkaline basalts erupted in eastern Iran north of ...Web
اقرأ أكثرLate Paleozoic Rifting in northern Pakistan
Postrifting thermal subsidence led to the deposition of Upper Triassic marine carbonate rocks which unconformably overlie the rift basalts. A similar tectonic history in central Afghanistan suggests continuity between the two regions prior …Web
اقرأ أكثرWhat Is Basalt?
Basalt is the dark, heavy volcanic rock that makes up most of the world's oceanic crust. Some of it erupts on land, too, but to a first approximation, basalt is an oceanic rock. Compared to the familiar granite of the continents, basalt ("ba-SALT") is darker, denser and finer grained. It's dark and dense because it's richer in the dark, …Web
اقرأ أكثرThe longest voyage: Tectonic, magmatic, and
The associations between flood basalts and the recurrent separation of the Indian plate from Gondwana are assessed. ... overthrusting onto the Campanian sedimentary unit constraints the onset of the collision between the Indian plate and Afghan block to the Late Cretaceous. The subsequent obduction of combined …Web
اقرأ أكثرEocene paleoelevation of the Tuoyun Basin, northeastern Pamirs
In general, vesicular basalts in acquisition and core of three-dimensional CT data, using different materials to ray absorption attenuation coefficient of inconsistency, ... sedimentary phase and tectonic stress analysis of the Meso-Cenozoic sedimentary strata of the Tajik Basin and the Afghan Massif on the western side of the Pamir, and found ...Web
اقرأ أكثرA Timeline Of Afghanistan's 4 Decades Of Instability : NPR
Babrak Karmal is installed as Afghanistan's Soviet-backed ruler. Groups of guerrilla fighters known as mujahideen or holy warriors mount opposition and a jihad …Web
اقرأ أكثر(PDF) Basalt from the Extinct Spreading Center in the
These mafic rocks comprise pillow basalts characterized by a vesicular structure. The mid-ocean ridge basalt (MORB)-normalized trace element patterns of basalts from the study area display ...Web
اقرأ أكثرDepleted and ultradepleted basalt and picrite in the Davis Strait
Depleted and enriched basalts in the Hellefisk well show contemporaneous melting of depleted and enriched mantle components in the asthenosphere. The Hekja and Davis Strait High basalts and picrites have unique, ultradepleted compositions with (La/Sm) N < 0.5, (Tb/Lu) N < 1 and Nb/Zr = 0.013–0.027. We interpret these compositions as a product ...Web
اقرأ أكثرBasalt: Igneous Rock
Basalt is also an abundant rock on the Moon. Much of the Moon's surface is underlain by basaltic lava flows and flood basalts. These areas of the Moon are known as "lunar maria." Large areas of the Moon have been …Web
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