NWA 960

Ordinary ChondriteWork in Progress Ordinary chondrites (OCs) are the largest meteorite clan, comprising approximately 87% of the global collection and 78% of all falls (Meteoritical Society database 2018)1. Meteorites & the Early Solar System: page 581 section 6.1 OC of type 5 or 6 with an apparent shock stage of S1,, type 3, metal-poor
(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).)

Purchased December 2001
no coordinates recorded A single stone weighing 997 g was found in Northwest Africa and purchased by A. and G. Hupé in Erfoud, Morocco. Samples were sent for analysis to the University of Washington, Seattle (A. Irving and S. Kuehner) and the Johnson Space Center, Houston (M. Zolensky). This 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 contains mostly sub-mm-sized 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 which are primarily olivine-rich, but a minor component of low-Ca 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. chondrules is present. It was determined that 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 and pyroxene have Fa and Fs values that lie outside of the range of the ordinary–rumurutiiteMember of a rare group of chondrites, formerly named the Carlisle Lakes group, after a meteorite found in Australia in 1977. It is now named for the type specimen Rumuruti that fell in Kenya, Africa, in 1934. Rumuruti is the only witnessed fall of this group and only one small 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 clan. Minor mineralInorganic substance that is (1) naturally occurring (but does not have a biologic or man-made origin) and formed by physical (not biological) forces with a (2) defined chemical composition of limited variation, has a (3) distinctive set of of physical properties including being a solid, and has a (4) homogeneous phases include 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., troiliteBrass colored non-magnetic mineral of iron sulfide, FeS, found in a variety of meteorites., 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, chromiteBrownish-black oxide of chromium and iron (Cr-Fe oxide), Cr2FeO4, found in many meteorite groups. and glass. FeNi-metal is absent, possibly due to its complete oxidationOxidation 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 to magnetite.

In an effort to resolve the group to which this meteorite belongs, two separate labs were employed for 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 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. analysis—the University of Chicago (R. Clayton) and the Carnegie Institution, Washington D.C. (D. Rumble III). On an oxygen three-isotope diagram, the values plot outside of the field of the ordinary–rumurutiite chondrite clan, and after five years of study, it was decided that NWA 960 is best considered an anomalous, metal-poor, non-carbonaceous chondrite. Along with NWA 960, a small number of anomalous, ungrouped, non-carbonaceous 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 have been studied and classified to date including HaH 180, NWA 2335, and NWA 2336, for which O-isotopic comparisons have been made to explore any possible genetic relationships (i.e., same 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.) among them. As shown on an oxygen three-isotope diagram, constructed by Achim Raphael, these meteorites plot very close to each other and might constitute a distinct field.

An additional small number of metal-poor, ungrouped non-carbonaceous chondrites have also been studied and classified to date, including the following members of the NWA-series: 2040 [LL], 2041 [L], 3114 [L], 3127 [LL], 3157 [L], 4294 [LL], 4298 [LL], 4486 [L], 4531 [LL], and 5717 [L+LL]). Oxygen isotopic analyses infer a possible ‘supra-TFL’ genetic grouping for these meteorites, which have a slope distinct from the ordinary chondrites (H, L, and LL) as illustrated on the oxygen three-isotope diagram below.
Diagram credit: Rumble III et al., 38th LPSC, #2230 (2007) See further details about this ‘supra-TFL’ grouping of meteorites on the HaH 180 page. Northwest Africa 960 is very weakly shocked to stage S1, and weathered to grade W1–2. The photo above shows a 5.2 g partial slice of this anomalous chondrite.