24° 50′ N., 31° 40′ E. Five stones with black, bubbly Outermost layer of a differentiated planet, asteroid or moon, usually consisting of silicate rock and extending no more than 10s of km from the surface. The term is also applied to icy bodies, in which case it is composed of ices, frozen gases, and accumulated meteoritic material. On Earth, the Click on Term to Read More were found by a member of the Geological Survey of Egypt in a farm field on the Nile River near Luxor. Today only a single 23 kg specimen remains preserved.
MIL CO3 chondrites: 3.2
DOM CO3 chondrites: 3.2
Felix, Lancé, and Ornans: 3.4
Isna: 3.7 Isna represents one of the most highly metamorphosed CO meteorites, both thermally and aqueously. The peak metamorphic temperature of Isna was ~530°C, reflected by its higher Ni and Co content, lower Cr in kamacite concentration, very coarse texture, decreased abundance of presolar diamonds, and increased TL sensitivity due to An alumino-silicate mineral containing a solid solution of calcium, sodium and potassium. Over half the Earth’s crust is composed of feldspars and due to their abundance, feldspars are used in the classification of igneous rocks. A more complete explanation can be found on the feldspar group page. Click on Term to Read More Physical or chemical process or action that results in the formation of regularly-shaped, -sized, and -patterned solid forms known as crystals. Click on Term to Read More from Roughly spherical aggregate of coarse crystals formed from the rapid cooling and solidification of a melt at ~1400 ° C. Large numbers of chondrules are found in all chondrites except for the CI group of carbonaceous chondrites. Chondrules are typically 0.5-2 mm in diameter and are usually composed of olivine Click on Term to Read More glass. Compared to other CO chondrites, Isna has an exceptionally low Time interval that a meteoroid was an independent body in space. In other words, the time between when a meteoroid was broken off its parent body and its arrival on Earth as a meteorite - also known simply as the "exposure age." It can be estimated from the observed effects Click on Term to Read More of ~0.15 m.y. A high solar Element occurring in the right-most column of the periodic table; also called "inert" gases. In these gases, the outer electron shell is completely filled, making them very unreactive. Click on Term to Read More content attests to a Mixture of unconsolidated rocky fragments, soil, dust and other fine granular particles blanketing the surface of a body lacking an atmosphere. Regolith is the product of "gardening" by repeated meteorite impacts, and thermal processes (such as repeated heating and cooling cycles). Click on Term to Read More origin. A high hydrothermal alteration is reflected in the increased size and abundance of rimmed AOAs, an apparant increase in chondrule size, and melilite-rich Inclusions found predominantly in carbonaceous chondrites and are rich in refractory elements particularly calcium, aluminum and titanium that in various combinations form minerals such as spinel, melilite, perovskite and hibonite. There are two types of refractory inclusion: • Ca Al-rich inclusions (CAIs) • Amoeboid olivine aggregates (AOAs) Refractory inclusions were Click on Term to Read More altered to fine-grained, spinel–A class of silicate (SiO3) minerals that form a solid solution between iron and magnesium and can contain up to 50% calcium. Pyroxenes are important rock forming minerals and critical to understanding igneous processes. For more detailed information, please read the Pyroxene Group article found in the Meteoritics & Classification Click on Term to Read More inclusions. In addition, 16O compositions are lowest in the highest petrographic subtypes, reflecting an increased Element that makes up 20.95 vol. % of the Earth's atmosphere at ground level, 89 wt. % of seawater and 46.6 wt. % (94 vol. %) of Earth's crust. It appears to be the third most abundant element in the universe (after H and He), but has an abundance only Click on Term to Read More exchange in an 16O-poor water reservoir during hydrothermal metamorphism. Some theories have linked the CO3 group to the K-type asteroids of the Eos family, an asteroid group that possesses S-type spectra in visible wavelengths and C-type spectra in the near-infrared. Based on reflectance spectra and Ratio of the amount of light reflected by an object and the amount of incident light. Albedo is used as a measure of the reflectivity or intrinsic brightness of an object. A white, perfectly reflecting surface has an albedo of 1.0 while a black perfectly absorbing surface would have an Click on Term to Read More, the asteroids 221 Eos (104 km-diameter) and 653 Berenike (39 km-diameter) were found to be good analogs for the olivine-rich CO3 meteorites. These asteroids are located near 3 The astronomical unit for length is described as the "mean" distance (average of aphelion and perihelion distances) between the Earth and the Sun. Though most references state the value for 1 AU to be approximately 150 million kilometers, the currently accepted precise value for the AU is 149,597,870.66 km. The Click on Term to Read More at the 9:4 resonance, where meteorites are expected to become Earth-crossers on timescales greater than tens of millions of years (see diagram below). However, utilizing more advanced spectrographic techniques comparing a broader spectrum, it was determined that a better fit to the Eos family was the Modifying term used to describe meteorites that are mineralogically and/or chemically unique and defy classification into the group or sub-group they most closely resemble. Some examples include Ungrouped Achondrite (achondrite-ung), Ungrouped Chondrite (chondrite-ung), Ungrouped Iron (iron-ung), and Ungrouped Carbonaceous (C-ung). Click on Term to Read More An achondrite is a type of stony meteorite whose precursor was of chondritic origin and experienced metamorphic and igneous processes. They have a planetary or differentiated asteroidal origin where the chondritic parent body reached a sufficient size that through heating due to radioactive decay of 26Al (isotope of Aluminum) and Click on Term to Read More Divnoe (Mothé-Diniz and Carvano, 2005).
Diagram credit: M. M. M. Meier et al., Earth and Planetary Science Letters, vol. 490 (2018)
‘Cosmic history and a candidate parent asteroid for the quasicrystal-bearing Work in progress. A solid natural object reaching a planet’s surface from interplanetary space. Solid portion of a meteoroid that survives its fall to Earth, or some other body. Meteorites are classified as stony meteorites, iron meteorites, and stony-iron meteorites. These groups are further divided according to their mineralogy and Click on Term to Read More Khatyrka’
(https://doi.org/10.1016/j.epsl.2018.03.025) Isna has an average The volume percentage of a rock that consists of void space. Vesicular porosity is a type of porosity resulting from the presence of vesicles, or gas bubbles, in igneous rock such as the pumice presented here. Vesicular porosity is very rare in meteorites and is often associated with slag, one Click on Term to Read More of 14.5% (Macke et al., 2011). For additional information on the formation of the CO chondrites and their metamorphic heirarchy, visit the Colony page. The specimen of Isna shown above is a 4.5 g partial slice.