(C3-ung in MetBull 80)
Found June 1995
27° 16.03′ N., 16° 25.22′ E. A stone weighing 451 g was found in the Libyan Sahara. It is shocked to stage S1 and has a weathering grade of W1. The main massLargest fragment of a meteorite, typically at the time of recovery. Meteorites are commonly cut, sliced or sometimes broken thus reducing the size of the main mass and the resulting largest specimen is called the "largest known mass". Click on Term to Read More is at the University of Humboldt in Berlin. A 703 g stone recovered nearby, designated DaG 056, is thought to be paired with DaG 055 based on similar cosmic-ray exposure ages (6.1 and 6.3 m.y. respectively), similar bulk compositions, and their close proximity when found. In 1998, stones were found nearby that might also be paired with DaG 055—DaG 429 (253 g) and DaG 430 (572 g; CRE age of 5.9 m.y.). Notably, only DaG 056 has been found to contain solar-type rare gases indicative of a regolithMixture 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. Another type-3 carbonaceous chondriteCarbonaceous chondrites represent the most primitive rock samples of our solar system. This rare (less than 5% of all meteorite falls) class of meteorites are a time capsule from the earliest days in the formation of our solar system. They are divided into the following compositional groups that, other than Click on Term to Read More, NWA 1665, has an O-isotope composition that plots near the DaG 055 pairing group, and it has been suggested that it could also be related.
Characteristics observed in DaG 055 and 056 are similar to those of reducedOxidation and reduction together are called redox (reduction and oxidation) and generally characterized by the transfer of electrons between chemical species, like molecules, atoms or ions, where one species undergoes oxidation, a loss of electrons, while another species undergoes reduction, a gain of electrons. This transfer of electrons between reactants Click on Term to Read More CV chondritesMeteorite class named after the Vigarano meteorite that fell in Italy in 1910. They have abundant large, well-defined rimless (?) chondrules of magnesium-rich olivine (~0.7 mm diameter; 40-65 vol. %), often surrounded by iron sulfide. They also contain 7-20 vol. % CAIs. The often dark-gray matrix is dominated by Fe-rich Click on Term to Read More
, but significant differences suggest the use of an ‘anomalous’ suffix. ChondruleRoughly 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
sizes of DaG 055 are large (ave. 790 µm), similar to sizes found in CV chondritesChondrites are the most common meteorites accounting for ~84% of falls. Chondrites are comprised mostly of Fe- and Mg-bearing silicate minerals (found in both chondrules and fine grained matrix), reduced Fe/Ni metal (found in various states like large blebs, small grains and/or even chondrule rims), and various refractory inclusions (such Click on Term to Read More
(ave. 750 µm; Choe et al.
, 2010). Igneous rims are present on chondrulesRoughly 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
in both meteorites, attesting to their formation in a dusty region of the nebulaAn immense interstellar, diffuse cloud of gas and dust from which a central star and surrounding planets and planetesimals condense and accrete. The properties of nebulae vary enormously and depend on their composition as well as the environment in which they are situated. Emission nebula are powered by young, massive Click on Term to Read More
. A low abundance of AOAs along with rare CAIsSub-millimeter to centimeter-sized amorphous objects found typically in carbonaceous chondrites and ranging in color from white to greyish white and even light pink. CAIs have occasionally been found in ordinary chondrites, such as the L3.00 chondrite, NWA 8276 (Sara Russell, 2016). CAIs are also known as refractory inclusions since they Click on Term to Read More
are present in DaG 055 as well as CV chondrites. The opaques consist of FeNi-metal and sulfide at abundances consistent with reduced CV chondrites. The O-isotope values of DaG 055 plot along the CCAM line within the CO and CV fields. Clayton and Mayeda (1999) describe a similar oxygenElement 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
plot in the middle of the CK field.
According to one research team, refractory lithophile elementElement that tends to be concentrated in the silicate phase, e.g., B, O, halogens, alkali earths, alkali metals, Al, Si, Sc, Ti, V, Cr, Mn, Y, Zr, Nb, REE, Hf, Ta, W, Th, and U.
abundances fallMeteorite seen to fall. Such meteorites are usually collected soon after falling and are not affected by terrestrial weathering (Weathering = 0). Beginning in 2014 (date needs confirmation), the NomComm adopted the use of the terms "probable fall" and "confirmed fall" to provide better insight into the meteorite's history. If Click on Term to Read More
within the CV-group range, while another team concluded that they plot higher than all chondriteChondrites are the most common meteorites accounting for ~84% of falls. Chondrites are comprised mostly of Fe- and Mg-bearing silicate minerals (found in both chondrules and fine grained matrix), reduced Fe/Ni metal (found in various states like large blebs, small grains and/or even chondrule rims), and various refractory inclusions (such Click on Term to Read More
groups. By comparison, siderophile and chalcophile abundances are more CV-like (Huber et al.
, 2006). Certain moderately volatile elementsChemical elements that condense (or volatilize) at relatively low temperatures. The opposite of volatile is refractory. Volatile elements can be divided into moderately volatile (Tc = 1230–640 K) and highly volatile (Tc < 640 K). The moderately volatile lithophile elements are: Mn, P, Na, B ,Rb, K, F, Zn. The moderately Click on Term to Read More
plot near the CV field, as do volatileSubstances which have a tendency to enter the gas phase relatively easily (by evaporation, addition of heat, etc.).
siderophile and chalcophile elements. DaG 055 has unequilibrated olivines with a composition of Fa0.4
, in the range of equilibrated CV-group members (Fa31
). It also shows similarities to the CK3 Camel Donga 003, but exhibits lower than normal 129
Xe ratios. A porosityThe 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
measurememt was made for the probable pairing DaG 056, and it was determined to be 2.25 (±1.42) vol% (M. Strait, 2010).
It has been proposed by some (e.g.
, Greenwood et al.
,2009 and Wasson et al.
, 2013) that the CK group is consistent with a metamorphicRocks that have recrystallized in a solid state due to changes in temperature, pressure, and chemical environment. Click on Term to Read More
extension of the CV group (see the Dhofar 015
page for more detailed information). The specimen of DaG 055 shown above is a 0.8 g fragment partially covered by fusion crustMelted exterior of a meteorite that forms when it passes through Earth’s atmosphere. Friction with the air will raise a meteorite’s surface temperature upwards of 4800 K (8180 °F) and will melt (ablate) the surface minerals and flow backwards over the surface as shown in the Lafayette meteorite photograph below. Click on Term to Read More