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Eucrite
Eucrites are achondritic stony meteorites, many of which originate from the surface of the asteroid 4 Vesta and are part of the HED meteorite clan. They are the most common achondrite group with over 100 meteorites found. Eucrites consist of basaltic rock from the crust of 4 Vesta or a similar parent body. They are mostly composed of calcium-poor pyroxene, pigeonite, and calcium-rich plagioclase ( anorthite). Based on differences of chemical composition and features of the component crystals, they are subdivided into several groups: * Non-cumulate eucrites are the most common variety and can be subdivided further: ** Main series eucrites formed near the surface and are mostly regolith breccias lithified under the pressure of overlying newer deposits. ** Stannern trend eucrites are a rare variety. ** Nuevo Laredo trend eucrites are thought to come from deeper layers of 4 Vesta's crust, and are a transition group towards the cumulate eucrites. * Cumulate eucrites are rare typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4 Vesta
Vesta (minor-planet designation: 4 Vesta) is one of the largest objects in the asteroid belt, with a mean diameter of . It was discovered by the German astronomer Heinrich Wilhelm Matthias Olbers on 29 March 1807 and is named after Vesta, the virgin goddess of home and hearth from Roman mythology. Vesta is thought to be the second-largest asteroid, both by mass and by volume, after the dwarf planet Ceres, though in volume it overlaps with the uncertainty in the measurements of 2 Pallas.Marsset, M., Brož, M., Vernazza, P. et al. The violent collisional history of aqueously evolved (2) Pallas. Nat Astron 4, 569–576 (2020). https://doi.org/10.1038/s41550-019-1007-5 Measurements give it a nominal volume only slightly larger than that of Pallas (about 5% greater, which is the magnitude of the uncertainties in measurement), but it is 25% to 30% more massive. It constitutes an estimated 9% of the mass of the asteroid belt. Vesta is the only known remaining rocky protoplanet (with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HED Meteorite
HED meteorites are a clan (subgroup) of achondrite meteorites. HED stands for "howardite–eucrite–diogenite". These achondrites came from a differentiated parent body and experienced extensive igneous processing not much different from the magmatic rocks found on Earth and for this reason they closely resemble terrestrial igneous rocks. Classification HED meteorites are broadly divided into: * Howardites * Eucrites * Diogenites Several subgroups of both eucrites and diogenites have been found. The HED meteorites account for about 5% of all falls, which is about 60% of all achondrites. Origin No matter their composition all these types of meteorite are thought to have originated in the crust of the asteroid Vesta. According to this theory the differences of composition are due to their ejection at different moments in the geologic history of Vesta. Their crystallization ages have been determined to be between 4.43 and 4.55 billion years from radioisotope ratios. HED meteorit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achondrite
An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies. As a result, achondrites have distinct textures and mineralogies indicative of igneous processes. Achondrites account for about 8% of meteorites overall, and the majority (about two-thirds) of them are HED meteorites, possibly originating from the crust of asteroid 4 Vesta. Other types include Martian, Lunar, and several types thought to originate from as-yet unidentified asteroids. These groups have been determined on the basis of e.g. the Fe/ Mn chemical ratio and the 17O/18O oxygen isotope ratios, thought to be characteristic "fingerprints" for each parent body. Classification Achondrites are classified into the following groups:O. Richard Norton. The Cambridge encyclopedia of meteorites. U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achondrite
An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies. As a result, achondrites have distinct textures and mineralogies indicative of igneous processes. Achondrites account for about 8% of meteorites overall, and the majority (about two-thirds) of them are HED meteorites, possibly originating from the crust of asteroid 4 Vesta. Other types include Martian, Lunar, and several types thought to originate from as-yet unidentified asteroids. These groups have been determined on the basis of e.g. the Fe/ Mn chemical ratio and the 17O/18O oxygen isotope ratios, thought to be characteristic "fingerprints" for each parent body. Classification Achondrites are classified into the following groups:O. Richard Norton. The Cambridge encyclopedia of meteorites. U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroidal Achondrite
An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies. As a result, achondrites have distinct textures and mineralogies indicative of igneous processes. Achondrites account for about 8% of meteorites overall, and the majority (about two-thirds) of them are HED meteorites, possibly originating from the crust of asteroid 4 Vesta. Other types include Martian, Lunar, and several types thought to originate from as-yet unidentified asteroids. These groups have been determined on the basis of e.g. the Fe/ Mn chemical ratio and the 17O/18O oxygen isotope ratios, thought to be characteristic "fingerprints" for each parent body. Classification Achondrites are classified into the following groups:O. Richard Norton. The Cambridge encyclopedia of meteorites. UK ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroidal Achondrites
An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies. As a result, achondrites have distinct textures and mineralogies indicative of igneous processes. Achondrites account for about 8% of meteorites overall, and the majority (about two-thirds) of them are HED meteorites, possibly originating from the crust of asteroid 4 Vesta. Other types include Martian, Lunar, and several types thought to originate from as-yet unidentified asteroids. These groups have been determined on the basis of e.g. the Fe/ Mn chemical ratio and the 17O/18O oxygen isotope ratios, thought to be characteristic "fingerprints" for each parent body. Classification Achondrites are classified into the following groups:O. Richard Norton. The Cambridge encyclopedia of meteorites. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial planet, rocky planet or natural satellite, moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of volcanism on Venus, Venus, which cover ~80% of the surface, are basaltic; the lunar mare, lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossary Of Meteoritics
This is a glossary of terms used in meteoritics, the science of meteorites. # * 2 Pallas – an asteroid from the asteroid belt and one of the likely parent bodies of the CR meteorites. * 4 Vesta – second-largest asteroid in the asteroid belt and likely source of the HED meteorites. * 221 Eos – an asteroid from the asteroid belt and one of the likely parent bodies of the CO meteorites. * 289 Nenetta – an asteroid from the asteroid belt and one of the likely parent bodies of the angrites. * 3103 Eger – an asteroid from the asteroid belt and one of the likely parent bodies of the aubrites. * 3819 Robinson – an asteroid from the asteroid belt and one of the likely parent bodies of the angrites. * IA meteorite – an iron meteorite group now part of the IAB group/complex. * IAB meteorite – an iron meteorite and primitive achondrite of the IAB group/complex. * IB meteorite – an iron meteorite group now part of the IAB group/complex. * IC meteorite – an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basaltic
Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of Venus, which cover ~80% of the surface, are basaltic; the lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flows that can spread over great areas before cooling and solidifying. Flood basalts are thick sequence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diogenite
Diogenites are a group of the HED meteorite clan, a type of achondritic stony meteorites. Origin and composition Diogenites are currently believed to originate from deep within the crust of the asteroid 4 Vesta, and as such are part of the HED meteorite clan. There are about 40 distinct members known. Diogenites are composed of igneous rocks of plutonic origin, having solidified slowly enough deep within Vesta's crust to form crystals which are larger than in the eucrites. These crystals are primarily magnesium-rich orthopyroxene, with small amounts of plagioclase and olivine. Name Diogenites are named for Diogenes of Apollonia, an ancient Greek philosopher who was the first to suggest an outer space origin for meteorites. See also * Glossary of meteoritics * Vesta family The Vesta family (adj. ''Vestian''; ) is a family of asteroids. The cratering family is located in the inner asteroid belt in the vicinity of its namesake and principal body, 4 Vesta. It is one of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithification
Lithification (from the Ancient Greek word ''lithos'' meaning 'rock' and the Latin-derived suffix ''-ific'') is the process in which sediments compact under pressure, expel connate fluids, and gradually become solid rock. Essentially, lithification is a process of porosity destruction through compaction and cementation. Lithification includes all the processes which convert unconsolidated sediments into sedimentary rocks. Petrifaction, though often used as a synonym, is more specifically used to describe the replacement of organic material by silica in the formation of fossils. See also * Diagenesis * Parent rock * Weathering Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), ... References {{Geology-stub Geological processes Sedimentary rocks Petrology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetary Science
Planetary science (or more rarely, planetology) is the scientific study of planets (including Earth), celestial bodies (such as moons, asteroids, comets) and planetary systems (in particular those of the Solar System) and the processes of their formation. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation, interrelations and history. It is a strongly interdisciplinary field, which originally grew from astronomy and Earth science, and now incorporates many disciplines, including planetary geology, cosmochemistry, atmospheric science, physics, oceanography, hydrology, theoretical planetary science, glaciology, and exoplanetology. Allied disciplines include space physics, when concerned with the effects of the Sun on the bodies of the Solar System, and astrobiology. There are interrelated observational and theoretical branches of planetary science. Observational research can involve combinations of spac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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