Fell June 25, 1983 32° 55.5′ N., 105° 54.4′ E. At 7:00 in the evening, this unique 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 fell in Ningqiang County, Shaanxi Province, The People’s Republic of China. Four stones were recovered weighing 0.35, 0.38, 0.78, and 3.1 kg for a total of 4.61 kg. The curator for the majority of the material is the Zijin Shan Observatory, Academia Sinica, in Nanjing, People’s Republic of China.
Ningqiang is an unequilibrated carbonaceous 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 that petrographically and texturally resembles the oxidizedOxidation 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 CV3 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 (such as Allende) in its large, well-defined 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, its high abundance of dark inclusions and fine-grained fayalitic olivineGroup of silicate minerals, (Mg,Fe)2SiO4, with the compositional endpoints of forsterite (Mg2SiO4) and fayalite (Fe2SiO4). Olivine is commonly found in all chondrites within both the matrix and chondrules, achondrites including most primitive achondrites and some evolved achondrites, in pallasites as large yellow-green crystals (brown when terrestrialized), in the silicate portion Click on Term to Read MorematrixFine grained primary and silicate-rich material in chondrites that surrounds chondrules, refractory inclusions (like CAIs), breccia clasts and other constituents. Click on Term to Read More (50.5 vol%), its high magnetiteFe oxide, Fe2+Fe3+2O4, containing oxidized iron (Fe3+) found in the matrix of carbonaceous chondrites and as diagnostic component in CK chondrites. In CK chondrites, magnetite is typically chromian, containing several wt. % Cr2O3. Click on Term to Read More/FeNi-metal ratio, and in containing awaruiteNi-rich Fe metal, Ni3Fe, similar to taenite found in minor amounts in some meteorites. Awaruite is also known as josephinite, a mineral found as placer deposits in Josephine County, Oregon, and sometimes mistaken for a meteorite. Note: web.mineral.com incorrectly defines Awaruite as “Ni2Fe to Ni3Fe”, however the IMA Database of Click on Term to Read More (Ni >65 wt%) as its principal metalElement that readily forms cations and has metallic bonds; sometimes said to be similar to a cation in a cloud of electrons. The metals are one of the three groups of elements as distinguished by their ionization and bonding properties, along with the metalloids and nonmetals. A diagonal line drawn Click on Term to Read More phase. A metallic phase in Ningqiang containing ~39 wt% Co (wairauite?), similar to a Co-rich phase found in certain LL and R chondrites, is associated with troiliteBrass colored non-magnetic mineral of iron sulfide, FeS, found in a variety of meteorites. Click on Term to Read More and pentlanditeFe-Ni sulfide, (Fe,Ni)9S8, that is often associated with troilite, and found in the matrix and chondrules of CO, CV, CK and CR chondrites. The color is yellow-bronze with light bronze-brown streak and metallic luster. It typically forms during cooling of magmatic sulfide melts during the evolution of parent silicate melt. The Click on Term to Read More. Ningqiang also contains opaque assemblages within 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, chondrules, and matrix which are typically found in CV3 chondrites (Wang et al., 2006). These assemblages are low-temperature aqueous alteration products (peak temperatures for the Ningqiang parent bodyThe body from which a meteorite or meteoroid was derived prior to its ejection. Some parent bodies were destroyed early in the formation of our Solar System, while others like the asteroid 4-Vesta and Mars are still observable today. Click on Term to Read More were no higher than 300°C; Hsu et al., 2011) of pre-existing metal grains; these grains originated as an immiscibleThe property of liquids that are mutually insoluble (won't mix together) such as oil and water or metallic and silicate melts. Click on Term to Read More phase of a silicateThe most abundant group of minerals in Earth's crust, the structure of silicates are dominated by the silica tetrahedron, SiO44-, with metal ions occurring between tetrahedra). The mesodesmic bonds of the silicon tetrahedron allow extensive polymerization and silicates are classified according to the amount of linking that occurs between the melt during the formation of CAIs and chondrules.
Ningqiang contains a lower abundance of CAIs compared to CV3 chondrites, constituting ~2.0 vol% and 5.1 vol%, respectively. Several types of CAIs are present, including a rare anorthite-spinel-rich type which is thought to be both an alteration product of spinel-rich type A inclusions and the precursor material of type C inclusions; these CAIs indicate a link exists between type A and C inclusions (Wang and Hsu, 2009). In addition, these two inclusionFragment of foreign (xeno-) material enclosed within the primary matrix of a rock or meteorite. Click on Term to Read More types were the likely precursor material for the formation of Al-rich chondrules, which are consistent with a derivation from low refractory material. Hsu et al. (2011) contrasted the absence of hiboniteRefractory mineral, Ca-aluminate (CaAl12O19) that occurs in terrestrial metamorphic rocks and in CAIs of many chondrites. Meteoritic hibonite tends to be blue as seen in the meteorite Isheyevo (Ch/CB). Hibonite is one of the most refractory minerals found in primitive meteorites. Click on Term to Read More in CV and CK chondrites with the ~7% of CAIs in Ningqiang that are hibonite-bearing. They hypothesize that the component of hibonite-bearing CAIs which is 26Al-free/poor formed early in the inner Solar SystemThe Sun and set of objects orbiting around it including planets and their moons and rings, asteroids, comets, and meteoroids. prior to the injection of 26Al into the solar nebulaThe primitive gas and dust cloud around the Sun from which planetary materials formed. from a nearby stellar source, while that which is 26Al-rich formed after such injection.
Ningqiang has a similar ratio of volatileSubstances which have a tendency to enter the gas phase relatively easily (by evaporation, addition of heat, etc.). to 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 (e.g., Zn/Mn) and a similar induced TL sensitivity to that of Allende-type CV group members. However, it is more enriched in volatiles, carbonElement commonly found in meteorites, it occurs in several structural forms (polymorphs). All polymorphs are shown to the left with * indicating that it been found in meteorites and impact structures: a. diamond*; b. graphite*; c. lonsdalite*; d. buckminsterfullerene* (C60); e. C540; f. C70; g. amorphous carbon; h. carbon nanotube*. Click on Term to Read More, FeNi-metal, and magnetite compared to the Allende-type CV group. Ningqiang has a bulk composition close to that of the equilibrated CK chondrites for most elements, with other elements having abundances closer to those of the unequilibrated CV group members. Although the O-isotope ratios of Ningqiang are enriched in 16O relative to Allende, the ratios are more consistent with the CO group, suggesting that a close relationship exists between them. Interestingly, Ningqiang contains phosphoran olivine, an extrememly rare meteoriteWork 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 phase found only in main-group pallasites (and three specific terrestrial sources).
As a further comparison, Ningqiang has an average 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 size significantly smaller than that of 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, and is closest to that of the CK chondrites; however, the volume of chondrules is about two times greater than that in CK chondrites. Ningqiang contains only one-tenth the number of coarsely-rimmed chondrules than do members of the CV group, possibly due to an inefficient low-temperature rim attachment. An unusually high abundance of silicate inclusions known as aggregational chondrules are present. These chondrules probably formed in the solar 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 at an early stage of melting and were sintered together in a low-temperature environment. Utilizing grain and bulk densityMass of an object divided by its volume. Density is a characteristic property of a substance (rock vs. ice, e.g.). Some substances (like gases) are easily compressible and have different densities depending on how much pressure is exerted upon them. The Sun is composed of compressible gases and is much Click on Term to Read More measurements, Macke et al. (2011) have determined the 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 of Ningqiang to be 23.6%, with certain properties showing consistencies with the oxidized CV groups.
Nevertheless, Ningqiang is more highly depleted in refractory lithophiles than either Allende-type CV or the more unequilibrated CK members, and is actually most similar to the CO chondrites in this respect. This depletion is probably due to the lower abundance and smaller size of the refractory inclusionsInclusions 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. Such a large difference in the refractory inclusionInclusions 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 abundances between Ningqiang and Allende-type CV chondrites can be explained by a later formation for Ningqiang, giving the Allende-type CV chondrites the opportunity to agglomerate a large portion of the coarser refractories that settled out early into the nebular midplane. Ningqiang also has a unique cosmic-ray exposure ageTime 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 ~42 m.y., which is much higher than most CV members. The meteorite has experienced only low shock effects.
In an effort to further resolve differences between the CV and CK chondriteClass of carbonaceous chondrite named for the Karoonda meteorite that fell in Australia in 1930. They are more oxidized than all other carbonaceous chondrites and genetically distinct from CV chondrites. CK chondrites appear dark-gray or black due to a high percentage of Cr-rich magnetite dispersed in a matrix of dark Click on Term to Read More groups, Yin and Sanborn (2019) analyzed Cr isotopes in a significant number and broad range of meteorites. Their study included samples from each of the three CV subgroups (oxA, oxB, Red), two anomalous CV3 (NWA 6047 and NWA 7891), a C3-ungrouped (Ningqiang), several CK members, and other potential CV-related meteorites (see top diagram below). It is demonstrated that the CV and CK meteorites are clearly resolved into two distinct isotopic reservoirs. In addition, it is shown in the top diagram below that the ε54Cr value for NWA 6047 puts it in a distinct location compared to other CV group meteorites, and therefore it may represent a separate carbonaceous chondrite parent body. Furthermore, despite the varied classification history of Ningqiang, it can now be assigned to the CK group. A coupled Δ17O vs. ε54Cr diagram plotting all of the meteorites in the study is shown in the bottom diagram below. Notably, anomalous CV3 NWA 7891 (Δ17O = –7.7 [±4.5] ‰) plots far below the range considered in the bottom diagram. Cr IsotopeOne of two or more atoms with the same atomic number (Z), but different mass (A). For example, hydrogen has three isotopes: 1H, 2H (deuterium), and 3H (tritium). Different isotopes of a given element have different numbers of neutrons in the nucleus. Click on Term to Read More Weighted Average For CV and CK Chondrites click on photo for a magnified view
O–Cr Diagram For CV and CK Chondrites CK: orange shades; CV: green shades; Achondrites: open click on photo for a magnified view
Diagrams credit: Yin and Sanborn et al., 50th LPSC, #3023 (2019) A unique dark inclusion (DI) was discovered in Ningqiang which represents some of the most pristine nebular material ever studied (Zolensky et al., 2003). It comprises two lithologies, both of which consist of µm-sized olivine and pyroxeneA 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 category. Click on Term to Read More crystals, but in only one are the silicates rimmed by amorphousMaterial without the regular, ordered structure of crystalline solids. Amorphous substances, like glass, lack a definite repeating pattern in their atomic structures (crystallinity). There may be small regions of order, but, overall there is disorder. Click on Term to Read More to microcrystalline material. These rims are thought to have formed through irradiation by bipolar outflows or FU-orionis flares from the nascent SunOur parent star. The structure of Sun's interior is the result of the hydrostatic equilibrium between gravity and the pressure of the gas. The interior consists of three shells: the core, radiative region, and convective region. Image source: http://eclipse99.nasa.gov/pages/SunActiv.html. The core is the hot, dense central region in which the, and in fact, this rim material is the carrier for Ar-rich, heavy primordial noble gasesElement 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 that were produced in a plasmaFourth state of matter: a gas in which many or most of the atoms are ionized. In the plasma state the atoms have split into positive ions and negative electrons, which can flow freely, so the gas becomes electrically conducting and a current can flow. Click on Term to Read More (Nakamura et al., 2003). In addition, an amorphous carbon phase in this DI contains both the dominant ‘Q’ noble gases (for ‘quintessence’) and exotic ‘HL’ noble gases (enriched in both heavy and light isotopes). This porous carbonaceous host phase for the Q-gases has been characterized by Amari et al. (2013) as nanoscale graphene platelets (see photo below). An in-depth investigation into the carbonaceous carrier of the Q-phase was conducted by Fisenko et al. (2018) utilizing the L4 chondrite Saratov. They contend that the carrier of the Q-gases is a nongraphitizing carbon phase present as curved, few-layer, graphene-like sheets which were likely formed in the protoplanetary nebula. The DI in the Ningqiang chondrite must have been incorporated after parent body aqueous alteration processes were complete and subsequent to partial annealing, since noble gases would have been quickly lost from host minerals through such oxidizingOxidation 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 alteration processes (Yamamoto et al., 2006). Photo and caption: Sachiko Amari et al., The Astrophysical Journal, vol. 778, #1 (2013) High-resolution aberration-corrected scanning transmission electron microscopy (STEM) image shows planar carbon ring structures inside graphene platelets in Q from acid-resistant residue of the L4 Saratov meteorite. Arrows indicate curled edges of graphene platelets. Most of the CAIs in Ningqiang contain Na-rich nepheline aggregates replacing meliliteGroup of minerals found in the CAIs of meteorites such as CV chondrites. Melilite consists almost exclusively of the binary solid solution gehlenite (Ca2Al2SiO7) – åkermanite (Ca2MgSi2O7). The melilite in CAIs is closer to gehlenite in composition. The first-formed (highest-temperature) melilite crystallizing from a melt is relatively aluminum-rich and becomes progressively Click on Term to Read More, which is thought to have occurred by a hydrothermal process (Sugita and Tomeoka, 2008). Moreover, the Ningqiang matrix has a higher Na content than CV3 matrices and is composed of two components derived from distinct parent body reservoirs: the first component consists of sub-µm-sized magnesian olivine with included nepheline (also derived from the reservoir from which the nepheline-containing CAIs originated), while the second component consists of larger than µm-sized ferroan olivine only rarely associated with nepheline, but does contain abundant grains of FeS and magnetite.
Trace amounts of the secondary alteration minerals sodalite and nepheline have been discovered in many components of Ningqiang. Considering the high abundance of sodalite observed in one DI relative to the expected abundance in the more porous matrix material, and understanding that the O-isotopic plot falls along the CCAM line, Wang and Hsu (2008, 2009) concluded that the sodalite and nepheline were formed in a nebular environment prior to parent body accretionAccumulation of smaller objects into progressively larger bodies in the solar nebula leading to the eventual formation of asteroids, planetesimals and planets. The earliest accretion of the smallest particles was due to Van der Waals and electromagnetic forces. Further accretion continued by relatively low-velocity collisions of smaller bodies in the Click on Term to Read More. Nakashima et al. (2008) presented further isotopic evidence indicating that nebular alteration processes were responsible for the formation of these secondary mineralMineral that forms through processes such as weathering, and in the case of meteorites can also include pre-terrestrial alteration. Secondary minerals in meteorites that formed during terrestrial weathering include oxides and hydroxides formed directly from metallic Fe-Ni by oxidation, phosphates formed by the alteration of schreibersite, and sulfates formed by Click on Term to Read More phases in Ningqiang. It is thought likely that sodalite and nepheline formation occurred through an alkali–halogenReactive nonmetal that is in Group 17 (VIIA) of the periodic table: F, Cl, Br, I and At. All of halogen elements are strongly electronegative. Click on Term to Read More metasomatic process involving anorthiteRare compositional variety of plagioclase and the calcium end-member of the plagioclase feldspar mineral series with the formula CaAl2Si2O8. Anorthite is found in mafic igneous rocks such as anorthosite. Anorthite is abundant on the Moon and in lunar meteorites. However, anorthite is very rare on Earth since it weathers rapidly Click on Term to Read More prior to its accretion to the parent body. In further studies of Ningqiang, Matsumoto et al. (2014) concluded that the fine-grained nepheline and sodalite now present in the matrix was initially formed through Na–Fe metasomatism and replacment of precursor chondrules and CAIs in the early stages of parent body formation. Thereafter, disaggregation of the altered chondrules, CAIs, and host matrix occurred, and the nepheline/sodalite was transported in a fluid and incorporated into the matrix grains of the meteorite source rock prior to final lithification. Matsumoto et al. (2017) suggest that the low abundance of CAIs and the small size and irregular shape of chondrules in Ningqiang, relative to typical CV3 chondrites, can be attibuted to this late-stage process.
Presolar silicate and oxide grains as well as grains exhibiting O-isotopic anomalies have been identified in Ningqiang matrix areas, with the abundance in one area reaching 230 ppmParts per million (106). Click on Term to Read More (Zhao et al., 2011). Most of these grains have 17O enrichments and likely formed around low- to intermediate-mass red giantGiant and highly luminous red star in the later stages of stellar evolution after it has left the main sequence. These red stars have a relatively cool surface whose core has burned most of its hydrogen. Red giants lose parts of their atmospheres and thus provide new elements into interstellar Click on Term to Read More branch stars and asymptotic giant branchPath on the Hertzsprung-Russell diagram corresponding to the changes that a star undergoes after He burning ceases in the core. At this stage, the C core shrinks and drives the expansion of the envelope, and the star becomes a red supergiant. Click on Term to Read More stars; however, a small number of the grains probably formed in supernovae. These presolar grainsMineral grains that formed before our solar system. These tiny crystalline grains are typically found in the fine-grained matrix of chondritic (primitive) meteorites. Most grains probably formed in supernovae or the stellar outflows of red giant (AGB) stars before being incorporated in the molecular cloud from which the solar system Click on Term to Read More are all enriched in Fe through a secondary Fe–alkali–halogen metasomatic process.
A Chinese–American team of scientists from the Chinese Academy of Sciences and Arizona State University have identified two short-lived radionuclides in Ningqiang—60Fe and 36Cl—both of which likely formed inside an earlier generation of massive stars, perhaps attaining 30–60× the mass of the Sun. Rapidly expanding UV radiation from such a massive starSelf-luminous object held together by its own self-gravity. Often refers to those objects which generate energy from nuclear reactions occurring at their cores, but may also be applied to stellar remnants such as neutron stars. could have produced a shock waveAbrupt perturbation in the temperature, pressure and density of a solid, liquid or gas, that propagates faster than the speed of sound. that triggered the formation of low-mass stars like the Sun. The final life stage of such a massive star is a supernovaStellar explosion that expels much or all of the stellar material with great force, driving a blast wave into the surrounding space, and leaving a supernova remnant. Supernovae are classified based on the presence or absence of features in their optical spectra taken near maximum light. They were first categorized Click on Term to Read More, which would have enriched our protoplanetary diskFlattened and rotating disk of dense gas and dust/solids orbiting a young star from which planets can eventually form. Click on Term to Read More with the short-lived radionuclides that we observe. However, it was recognized that a significant probability exists for such an event to disrupt the presolar nebula instead of causing its gravitational collapse. An alternative model was presented by Sahijpal and Gupta (2007) in which low-mass star formation occurs first as a result of local density fluctuations, and thereafter, a massive star (>40 M⊙) is formed within ~25 parsecs, perhaps through rapid accretion or through stellar mergers. This massive star is conjectured to have undergone coreIn the context of planetary formation, the core is the central region of a large differentiated asteroid, planet or moon and made up of denser materials than the surrounding mantle and crust. For example, the cores of the Earth, the terrestrial planets and differentiated asteroids are rich in metallic iron-nickel. Click on Term to Read More collapse and transition into a supernova within a short interval of ~3–5 m.y., injecting short-lived nuclides into the existing protoplanetary disk(s). This scenario is also consistent with the finding that the earliest CAIs contain no 26Al.
Bizzarro et al. (2007) found that the differentiated meteorites do not contain 60Fe, but that later-formed chondrites do, and that all of the meteorite types do contain 26Al. They believe the radiometric evidence indicates that 26Al was infused into the local nebula very early through stellar winds from a nearby massive star. Sahijpal and Gupta (2009) suggest that this massive star belonged to a common stellar cluster and was located ~3.5 parsecs from the protosun. Injection of radionuclides by this massive star into the presolar nebula could have occurred during a Wolf-Rayet stage or during a core collapse supernova ~1 m.y. after the onset of planetesimal agglomerationProcess of collecting in a jumbled cluster. In relation to meteorites, agglomeration refers to the early accretion of chondrules, refractory inclusions and silicate matrix material to form chondritic clusters. Click on Term to Read More, after which 26Al became homogeneously mixed throughout the nebula. The stellar winds from the massive star could even be primarily responsible for the initial collapse of the protosolar disk. Only after the supernova explosion occurred was the 60Fe released from the massive star’s interior and injected into the dust of newly accreting chondritic parent bodies. For additional information on the studies of Bizzarro et al. (2007) read the PSRD article by G. Jeffrey Taylor: ‘The Sun’s Crowded Delivery Room‘, July 2007.
Ningqiang has had a variable history with its classification, at one time or another being associated with the CV, CK, and CO groups, usually as an anomalous member, or otherwise considered to be ungroupedModifying 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 (G. Kallemeyn, 27th LPSC, #1318 ). Other analyses indicating lower than usual refractory lithophile abundances led to the general conclusion that Ningqiang would be best classified as an ungrouped C3 chondrite (e.g., Wasson et al., 2013). More recent isotopic analyses conducted by Yin and Sanborn (2019) establish a CK group membership for Ningqiang. The photo shown above is a 1.2 g interior fragment of Ningqiang, while the photo below shows a prominent CAISub-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 exposed inside of a broken edge.