Meteorite**NWA 13683; R3-6**4.639 gram gorgeous endcut, very rare type!!!

Description

Hello up for sale is NWA 13683 classified as a R3-6. This endcut weighs 4.639 gram, displays gorgeous chondrules , troilite, abundant pentlandite, phosphate and chromite inclusions. The Rumuruti (R) chondrites record environments rich in both S and O, making them ideal probes for volatile enhancement in the early Solar System. Oxidation trends in R chondrites are affected by both aqueous alteration and thermal metamorphism. The differing degrees of oxidation in this group reflect differences in local environments on the parent asteroid.
This meteorite was found in Adrar, Algeria 2018, comes with COA card. Thanks for your interest and take care!
Northwest Africa 13683
Basic informationName: Northwest Africa 13683
This is an OFFICIAL meteorite name.
Abbreviation: NWA 13683
Observed fall: No
Year found: 2018
Country: Algeria
Mass: 1959 g
Northwest Africa 13683 (NWA 13683)
Adrar, Algeria
Find: 2018
Classification: Rumuruti chondrite (R3-6)
History: Found between 2018-2019. Many meteorites weighing a total of 1959 grams were purchased by Adria_n Contreras Gómez from a Sahara seller in July 2020.
Physical characteristics: Sample lacks fusion crust, is irregular-shaped and shows abundant chondrules surrounded by sulfides.
Petrography: Description and classification (A. Love, App) Sample is a genomict chondrite breccia composed of rounded to angular clasts of unequilibrated and recrystallized textures occurring within a host of slightly flattened, dispersed chondrules, fragments and sulfide grains. Recrystallized clasts lack discernible chondrules and low Ca pyroxene, and contains a network of 50µm secondary plagioclase. Chondrules average apparent diameter 424µm (n=105). Additional minerals are: troilite, abundant pentlandite, phosphate and chromite.
Geochemistry: Host: olivine (Fa32.2±14.3, CV%=43 (R3.5), Fe/Mn=80.7±23.0, n=30); low Ca pyroxene (Fs6.6±6.0Wo1.0±0.8, Fe/Mn=19.7±11.6, n=7); pigeonite (Fs21.4±2.9Wo9.5±2.7, n=3); unequilibrated clast: olivine (Fa20.1±14.4, CV%=72 (R3.2), Fe/Mn=62.6±30.6, n=12); recrystallized clast: olivine (Fa37.6±0.1, Fe/Mn=73.1±3.6, n=6); high Ca pyroxene (Fs13.4±0.1Wo39.1±0.4, Fe/Mn=36.8±2.2, n=3).
Classification: Rumuruti chondrite (R3-6, C-S2, wi-2) Chondrule diameter, magnetic susceptibility, ubiquitous pentlandite and lack of FeNi metal suggest sample is an R chondrite. Based on unequilibrated compositions and coefficient of variation w/in clast and host, sample is an R3.2-6.
Specimens: Adrián Contreras holds the 290 g main mass. An endcut and several small fragments weighing 28.06 g and a polished thin section are on deposit at App.
State/Prov/County:Adrar
Date:2018
Mass (g):1959
Pieces:many
Class:R3-6
Shock stage:low
Weathering grade:wi-2
Fayalite (mol%):32.2±14.3; 20.1±14.4; 37.6±0.1Ferrosilite (mol%):6.6±6.0; 21.4±2.9; 13.4±0.1Wollastonite (mol%):1.0±0.8; 9.5±2.7; 39.1±0.4
Magnetic suscept.:3.16
Classifier:A. Love, App
Type spec mass (g):28.06
Type spec location: App
Main mass:Carlos Muñecas (Expometeoritos)Comments:Submitted by Anthony Love
Geochimica et Cosmochimica Acta
Volume 124, 1 January 2014, Pages 131-151
R-chondrite bulk-chemical compositions and diverse oxides: Implications for parent-body processes
Author links open overlay panelJunkoIsaabJohn T.Wassonabc
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https://doi.org/10.1016/j.gca.2013.09.018Get rights and content
Science direct says:
Abstract
R chondrites are among the most oxidized chondrite groups; they also have the highest Δ17O values known in whole-rock meteorites. We analyzed R chondrites (six Antarctic, four hot-desert) by instrumental neutron activation analysis. Data for one of the former and three of the latter show large weathering effects, but the remainder show only moderate scatter and permit us to determine trends and mean compositions for the group. Bulk R-chondrite compositions are similar to those in H and L chondrites, but the concentrations of several volatiles, especially Se and Zn, are higher; the more volatile the element, the higher the enrichment in R chondrites relative to H and L.
Petrologic types in R chondrites extend as low as 3.6. We determined olivine compositional distributions and studied opaque oxides in 15 R-chondrite thin sections, including a newly discovered R4 clast in Bencubbin (adding to the diversity of chondritic clasts in this polymict breccia) and an R clast in CM2 Murchison. Opaque oxides in R chondrites include nearly pure magnetite, Al-rich chromite, magnetite–chromite solid solution, nearly pure chromite, and ilmenite. This diverse set of opaque phases reflects differing aqueous-alteration conditions.
The least equilibrated R chondrites contain nearly pure magnetite but the spinels in metamorphosed R chondrites contain additional components (e.g., Cr2O3 and Al2O3 and some minor cations). The NiO content in olivine correlates with the magnetite component in magnetite–chromite solid solution in equilibrated R chondrites and is a function of the degree of oxidation. The absence of metallic Fe in A-881988 and LAP 031156 indicates a high degree of oxidation; the relatively low-FeO (Fa35) olivine in these rocks in part reflects the conversion of Fe2+ to Fe3+ and its partitioning into magnetite. Oxidation trends in R chondrites are affected by both aqueous alteration and thermal metamorphism. The differing degrees of oxidation in this group reflect differences in local environments on the parent asteroid.
Chondritic meteorites are undifferentiated fragments of asteroids that contain the oldest solids formed in our Solar System. Their primitive, solar-like chemical compositions indicate that they experienced very little processing following accretion to their parent bodies. As such, they retain the best records of chemical and physical processes active in the protoplanetary disk during planet formation. Chondritic meteorites are depleted relative to the sun in volatile elements such as S and O. In addition to being important components of organic material, these elements exert a strong influence on the behavior of other more refractory species and the composition of planets. Understanding their distribution is therefore of key interest to the scientific community. While the bulk abundance of volatile elements in solid phases present in meteorites is below solar values, some meteorites record volatile-rich gas phases. The Rumuruti (R) chondrites record environments rich in both S and O, making them ideal probes for volatile enhancement in the early Solar System. Disentangling the effects of parent-body processing on pre-accretionary signatures requires unequilibrated meteorite samples. These samples are rare in the R chondrites. Here, I report analyses of unequilibrated clasts in two thin sections from the same meteorite, PRE 95404 (R3.2 to R4). Data include high resolution element maps, EMP chemical analyses from silicate, sulfide, phosphate, and spinel phases, SIMS oxygen isotope ratios of chondrules, and electron diffraction patterns from Cu-bearing phases. Oxygen isotope ratios and chondrule fO2 levels are consistent with type II chondrules in LL chondrites. Chondrule-sized, rounded sulfide nodules are ubiquitous in both thin sections. There are multiple instances of sulfide-silicate relationships that are petrologically similar to compound chondrules, suggesting that sulfide nodules and silicate chondrules formed as coexisting melts. This hypothesis is supported by the presence of phosphate inclusions and Cu-rich lamellae in both sulfide nodules and sulfide assemblages within silicate chondrules. Thermodynamic analyses indicate that sulfide melts reached temperatures up to 1138 °C and fS2 of 2 x 10^(-3) atm. These conditions require total pressures on the order of 1 atm, and a dust- or ice-rich environment. Comparison with current models suggest that either the environmental parameters used to model chondrule formation prior to planetesimal formation should be adjusted to meet this pressure constraint, or R chondrite chondrules may have formed through planetesimal bow shocks or impacts. The pre-accretionary environment recorded by unequilibrated R chondrites was therefore highly sulfidizing, and had fO2 higher than solar composition, but lower than the equilibrated R chondrites.Chalcopyrite is rare in meteorites, but forms terrestrially in hydrothermal sulfide deposits. It was previously reported in the R chondrites. I studied thin sections from PRE 95411 (R3 or R4), PCA 91002 (R3.8 to R5), and NWA 7514 (R6) using Cu X-ray maps and EMP chemical analyses of sulfide phases. I found chalcopyrite in all three samples. TEM electron diffraction data from a representative assemblage in PRE 95411 are consistent with this mineral identification. TEM images and X-ray maps reveal the presence of an oxide vein. A cubanite-like phase was identified in PCA 91002. Electron diffraction patterns are consistent with isocubanite. Cu-rich lamellae in the unequilibrated clasts of PRE 95404 are the presumed precursor materials for chalcopyrite and isocubanite. Diffraction patterns from these precursor phases index to bornite. I hypothesize that bornite formed during melt crystallization prior to accretion. Hydrothermal alteration on the parent body by an Fe-rich aqueous phase between 200 and 300°C resulted in the formation of isocubanite and chalcopyrite. In most instances, isocubanite may have transformed to chalcopyrite and pyrrhotite at temperatures below 210°C. This environment was both oxidizing and sulfidizing, suggesting that the R chondrites record an extended history of volatile-rich interaction. These results indicate that hydrothermal alteration of sulfides on the R chondrite parent body was pervasive and occurred even in low petrologic types. This high temperature aqueous activity is distinct from both the low temperature aqueous alteration of the carbonaceous chondrites and the high temperature, anhydrous alteration of the ordinary chondrites.