Campo del Cielo – an Iron Meteorite found in Argentina

2021 ◽  
Vol 58 (9) ◽  
pp. 570-580
Author(s):  
R. Haubner ◽  
S. Strobl
Keyword(s):  
High Temperatures ◽  
Iron Meteorite ◽  
Iron Meteorites ◽  
Steel Microstructure

Abstract Fragments of the “Campo del Cielo” meteorite were first reported by conquistadores in Argentina in as early as 1576. This meteorite belongs to the group of iron meteorites and is classified as a group IA coarse octahedrite. The use of meteoric iron to make objects of daily use or hunting weapons in prehistoric times is only confirmed by very few finds. Metallographic examinations were performed to assess if it was realistic and in fact feasible to process meteoric iron. The bulk of the examined “Campo del Cielo” meteorite fragment found in Argentina is kamacite (α-Fe) with approx. 5.3 wt.% of dissolved Ni. Graphite was also detected in addition to various non-metallic phases. Due to high temperatures during processing, graphite can dissolve and a steel microstructure would form as a result.

Scanning Electron Microscopy And Electron Probe Microanalysis Of Extraterrestrial Materials

1999 ◽  
Vol 5 (S2) ◽  
pp. 2-3
Author(s):  
J. I. Goldstein
Keyword(s):  
Electron Microscopy ◽  
Low Temperatures ◽  
Electron Probe ◽  
Iron Meteorite ◽  
The Moon ◽  
Iron Meteorites ◽  
Slow Cooling ◽  
Electron Probe Microanalyzer ◽  
Extraterrestrial Materials ◽  
Scanning Electron

One of the first samples analyzed by Castaing in his electron probe microanalyzer (EPMA) some 50 years ago was an iron meteorite. The Widmanstatten pattern microstructure of iron meteorites can be observed at very low magnifications ( Fig. 1). These meteorites are ideal samples for microanalysis because of the Ni gradient which extends over 10 to 1000 microns in the parent taenite phase of these Fe-Ni samples (Fig. 3). The Ni gradient is the result of very slow cooling of the iron meteorite, in terms of millions of years, within a parent'asteroid.The scanning electron microscope (SEM) has been used to characterize the microstructure of meteorites, as well as samples from the moon and mars. For example, the microstructure of the dark etching taenite areas (T in Fig. 1) of the Carleton iron meteorite is shown in Fig 2. In this example, precipitates are observed along original martensite laths which form during the cooling of the iron meteorite at low temperatures.

scholarly journals Fe-Ni-P-S Melt Pockets in Elga IIE Iron Meteorite: Evidence for the Origin at High-Pressures Up to 20 GPa

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 616 ◽  
Author(s):  
Konstantin Litasov ◽  
Svetlana Teplyakova ◽  
Anton Shatskiy ◽  
Konstantin Kuper
Keyword(s):  
Experimental Data ◽  
Solid Solution ◽  
Important Implication ◽  
High Pressures ◽  
Bulk Composition ◽  
Parent Body ◽  
Iron Meteorite ◽  
Iron Meteorites ◽  
High Pressures And Temperatures ◽  
Melt Pockets

Here we report new data on high-pressure microstructures in Elga group IIE iron meteorites, made of solidified Fe-Ni-P-S melt pockets and microcrystalline aggregates, which could be formed only at high pressures and temperatures according to the experimental data. The bulk composition of the melt pockets and crystals correspond to the Fe3P-Fe3S solid solution with the closure of an immiscibility gap at pressures near 20 GPa in static experiments. Some other melt pockets fit with the Fe2S-Fe2P compositions, which could also correspond to high pressures and temperatures. The results suggest a late shock episode during the formation of the IIE iron parent body, which may be prior or due to the final disruption that caused the meteorite arrival to Earth. It also has an important implication to the shock features in other meteorites, such as ureilite.

Origin of Iron Meteorite Groups IAB and IIICD

1980 ◽  
Vol 35 (8) ◽  
pp. 781-795 ◽  
Author(s):  
John T. Wasson ◽  
John Willis ◽  
Chien M. Wai ◽  
Alfred Kracher
Keyword(s):  
Parent Body ◽  
Iron Meteorite ◽  
Iron Meteorites ◽  
Impact Melt ◽  
Equilibrium Crystallization ◽  
Ni Content ◽  
Oxide Phases ◽  
Host Metal ◽  
Impact Melts ◽  
The Impact

AbstractSeveral low-Ni iron meteorites previously assigned to group IAB are reclassified IIICD on the basis of lower Ge, Ga, W and Ir concentrations and higher As concentrations; the low-Ni extreme of IIICD is now 62 mg/g, that of IAB is 64 mg/g. The resulting fractionation patterns in the two groups are quite similar. It has long been established that, in contrast to the magmatic iron meteorite groups, IAB and IIICD did not form by fractional crystallization of a metallic magma. Other models have been proposed, but all have serious flaws. A new model is proposed involving the formation of each iron in small pools of impact melt on a parent body consisting of material similar to the chondritic inclusions found in some IAB and IIICD irons, but initially unequilibrated. These impact melts ranged in temperatures from ~ 1190 K to ~ 1350 K. The degree of equilibration between melt and unmelted solids ranged from minimal at the lowest temperature to moderate at the highest temperature. The lowest temperature melts were near the cotectic in the Fe-Ni-S system with Ni contents of ~ 12 atom %. Upon cooling, these precipitated metal having ~ 600 mg/g Ni by equilibrium crystallization. The Ni-rich melt resulted from the melting of Ni-rich sulfides and metal in the unequilibrated chondritic parent. Low-Ni irons formed in high temperature melts near the composition of the FeS-Fe eutectic or somewhat more metal rich. We suggest that the decreasing Ge, Ga and refractory abundances with increasing Ni concentration reflect the trapping of these elements in oxide phases in the unequilibrated chondritic material, and that very little entered the Ni-rich melt parental to the Oktibbeha County iron. The remaining elements tended to have element/Ni ratios in the melts that were more or less independent of temperature. The remarkable correlation between I-Xe age of the chondritic inclusions and Ni content of the host metal is explained by a detailed evolution of (mega)regolith in which these groups originated. The most Ni-rich melts could only be generated from an unequilibrated chondrite parent; as the continuing deposition of impact energy produced increasingly higher grades of metamorphism, the maximum Ni content of the impact melts (and their subsequently precipitated metal) gradually decreased.

Meteorite traces on a shatter cone surface from the Agoudal impact site, Morocco

2015 ◽  
Vol 152 (4) ◽  
pp. 751-757 ◽  
Author(s):  
M. SCHMIEDER ◽  
H. CHENNAOUI AOUDJEHANE ◽  
E. BUCHNER ◽  
E. TOHVER
Keyword(s):  
Iron Meteorite ◽  
Impact Structure ◽  
Iron Meteorites ◽  
Electron Microscopic ◽  
Impact Site ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Cone Surface ◽  
Shatter Cones ◽  
The Impact

AbstractThe recently discovered Agoudal impact site in Morocco is a small, eroded impact structure with well-developed shatter cones. A scanning electron microscopic study of a shatter cone surface has revealed the presence of schreibersite – a phosphide very rare on Earth but common in iron meteorites – and Fe–Ni oxides. This is the first reported evidence for primary meteoritic matter adherent to shatter cones and suggests that the Agoudal crater was formed by the impact of an iron meteorite, probably the Agoudal IIAB iron. Shatter cones from other terrestrial impact structures might also hold valuable information about the nature of the impacting projectiles.

A new method for high-precision palladium isotope analyses of iron meteorites and other metal samples

2017 ◽  
Vol 32 (3) ◽  
pp. 647-656 ◽  
Author(s):  
Mattias Ek ◽  
Alison C. Hunt ◽  
Maria Schönbächler
Keyword(s):  
High Precision ◽  
Iron Meteorite ◽  
New Method ◽  
Iron Meteorites ◽  
Icp Ms ◽  
Isotope Analyses

We present a new method for separation of Pd from an iron meteorite matrix and high precision analyses of all isotopes via multi collector ICP-MS.

Durch Spallationsreaktionen und Neutroneneinfang erzeugtes 36Cl in Meteoriten und die prae-atmosphärische Größe von Steinmeteoriten

1965 ◽  
Vol 20 (4) ◽  
pp. 533-540 ◽  
Author(s):  
F. Begemann ◽  
E. Vilcsek
Keyword(s):  
Mass Loss ◽  
Neutron Capture ◽  
Iron Meteorite ◽  
Iron Meteorites ◽  
Significance Level ◽  
Spallation Reactions ◽  
Limits Of Error ◽  
Good Agreement ◽  
Terrestrial Age ◽  
Comparable Size

The 36Cl produced by spallation reactions and neutron capture on 35Cl has been measured separately in three stone meteorites and one iron meteorite.The spallation produced 36Cl activities - given in dpm per kg (Fe+Ni + 10 x Ca) -have been found to be (20.5 ±2) for Abee - Centre, (21.8 ±2) for Abee - Surface, (21.3 -26.2) for Leedey, and ≦ (22 ±10) for Norton County- Surface. They are in good agreement with those found in iron meteorites of comparable size and known terrestrial age.The neutron induced activities in the same samples are (0.21 ±0.2), (0.08 ± 0.17), (1.7 ±1), and ≦ (30 ± 15) dpm/100 mg Cl. In spite of the large uncertainties highly significant conclusions can be drawn from these data regarding the mass loss of the meteorites during approximately the last million years, either by space erosion or due to ablation during the passage through the terrestrial atmosphere. Based on calculations of EBERHARDT, GEISS, and LUTZ the ratio of post-atmospheric to pre-atmospheric radius derived for the three meteorites is Abee: rM/R=0.86 or rΜ/R > 0.7 on the 3 σ significance level, Leedey (meteorite shower): rM/R=0.5, and Norton County: rM/R=0.77 or rM/R > 0.63 (3 σ level).No neutron induced activity could be detected in the iron meteorite Cranbourne (Nr. 4). The total and spallation produced 36Cl of two adjacent samples - although differing in their Cl content by more than a factor of twenty-was the same within the experimental limits of error (4.7 ± 0.2) dpm/kg. The low value is attributed to a high terrestrial age and/or the size of this meteorite. 39Ar could not be detected (< 0.64 dpm/kg. 3 σ level).

scholarly journals Early volatile depletion on planetesimals inferred from C–S systematics of iron meteorite parent bodies

2021 ◽  
Vol 118 (13) ◽  
pp. e2026779118
Author(s):  
Marc M. Hirschmann ◽  
Edwin A. Bergin ◽  
Geoff A. Blake ◽  
Fred J. Ciesla ◽  
Jie Li
Keyword(s):  
Thermodynamic Modeling ◽  
Open System ◽  
Closed System ◽  
Small Body ◽  
Parent Body ◽  
Iron Meteorite ◽  
Terrestrial Planets ◽  
Iron Meteorites ◽  
Body Core ◽  
Volatile Loss

During the formation of terrestrial planets, volatile loss may occur through nebular processing, planetesimal differentiation, and planetary accretion. We investigate iron meteorites as an archive of volatile loss during planetesimal processing. The carbon contents of the parent bodies of magmatic iron meteorites are reconstructed by thermodynamic modeling. Calculated solid/molten alloy partitioning of C increases greatly with liquid S concentration, and inferred parent body C concentrations range from 0.0004 to 0.11 wt%. Parent bodies fall into two compositional clusters characterized by cores with medium and low C/S. Both of these require significant planetesimal degassing, as metamorphic devolatilization on chondrite-like precursors is insufficient to account for their C depletions. Planetesimal core formation models, ranging from closed-system extraction to degassing of a wholly molten body, show that significant open-system silicate melting and volatile loss are required to match medium and low C/S parent body core compositions. Greater depletion in C relative to S is the hallmark of silicate degassing, indicating that parent body core compositions record processes that affect composite silicate/iron planetesimals. Degassing of bare cores stripped of their silicate mantles would deplete S with negligible C loss and could not account for inferred parent body core compositions. Devolatilization during small-body differentiation is thus a key process in shaping the volatile inventory of terrestrial planets derived from planetesimals and planetary embryos.

scholarly journals Ore Petrography, Mineralogical and Chemical Composition of New Iron Meteorite (Al-Sherqat Meteorite) from Iraq

2021 ◽  
Vol 54 (2E) ◽  
pp. 1-11
Author(s):  
Awadh Salih
Keyword(s):  
Chemical Composition ◽  
Total Mass ◽  
Iron Meteorite ◽  
Uniform Structure ◽  
Polished Section ◽  
Iron Meteorites ◽  
Northern Iraq ◽  
The Core ◽  
Probable Source ◽  
Continuous Plate

The meteorite with a single total mass of 630 gm as a visible meteorite has fallen on 22 March 2021, at 10:00 a.m. in Al-Sherqat subdistrict within Salah Al-Din, northern Iraq; and therefore, was named Al-Sherqat meteorite by the authors. It is characterized by a uniform structure of coherent and medium degree of malleability. It is of a well-crystalline structure and not homogeneous in composition. The Al-Sherqat meteorite is composed of metallic phases of 7.6 gm/cm3 density exhibiting an oriented intergrowth of kamacite (α-FeNi) with taenite showing a Widmanstätten pattern on an etched polished section with the finest octahedrite kamacite bandwidth of less than 0.2 mm. It is composed of Fe (86.9 wt%), Ni (9.63 wt%), P (1.31 wt%), S (0.628 wt%), Ti (0.623 wt%), Co (0.446 wt%), Mo (0.146 wt%), Cr (0.103 wt%), Cu (0.141 wt%), V (300 ppm), Nb (220 ppm), W (53 ppm), Ag (50 ppm), Pb (30 ppm), Zn (20 ppm), Sb (16 ppm), Sn (10 ppm) and As (3 ppm). Al-Sherqat meteorite was structurally classified as an iron meteorite belongs to the plessitic group (Opl)) with octahedrite finest bands (less than 0.2 mm) of the kamacite lamellae. Kamacite platelets in Al-Sherqat meteorite are almost not a continuous plate network. Chemically, it belongs to the IIC type of magmatic group based on the amount of nickel (9.63%), where IIC is typically octahedrites has 9.3 – 11.5% Ni. The presence of kamacite, taenite, schreibersite, daubréelites, pentlandite, chromite, and wusite in Al-Sherqat meteorite are in accordance with IIC group of the iron meteorites. Al-Sherqat meteorite belongs to M-type considering a metallic core fragmented by impact asteroid. The most probable source of this meteorite is the core of an asteroid that melted early in its history.

The Redfields meteorite—A unique iron from Western Australia

1973 ◽  
Vol 39 (301) ◽  
pp. 30-35 ◽  
Author(s):  
J. R. De Laeter ◽  
G. J. H. McCall ◽  
S. J. B. Reed
Keyword(s):  
Nickel Content ◽  
Iron Meteorite ◽  
Grain Structure ◽  
Iron Meteorites ◽  
High Carbon ◽  
Unusual Structure ◽  
Unique Type ◽  
Australian Museum ◽  
Graphite Inclusions ◽  
Western Australian

SummaryA metallic mass brought to the Western Australian Museum from the Wongan Hills district N.W. of Perth has been identified as an iron meteorite of unique type. It has graphite inclusions about I mm across distributed throughout the metal giving a ‘raisin bread’ appearance. Its nickel content (6·65 %) is comparable with that of coarse octahedrites but the kamacite grain structure is anomalous. Its gallium, germanium, and nickel contents place it close to, but outside, Wasson's chemical group IIb. Taenite is absent and troilite is rare. Neumann bands in the kamacite are distorted and the kamacite has flowed around large schreibersite inclusions. The latter have an exceptionally low nickel content (7·0 %) and probably formed at an unusually high temperature. The kamacite contains more phosphorus than normal iron meteorites, and small schreibersite grains in the kamacite are relatively nickel-poor (22 %). The unusual structure of this iron is thought to be due to one or more of the factors high carbon, high phosphorus, and relatively rapid cooling.

scholarly journals 57Fe Mössbauer Analysis of Meteorites and Tektites

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 628
Author(s):  
Benilde F.O. Costa ◽  
Eduardo Ivo Alves ◽  
Pedro A.O.C. Silva ◽  
António C. Batista
Keyword(s):  
Iron Meteorite ◽  
X Ray Diffraction ◽  
Iron Meteorites ◽  
X Ray ◽  
Electron Microscopies ◽  
Northwest Africa ◽  
Mimos Ii ◽  
Lower Temperature ◽  
Mössbauer Analysis ◽  
Stony Meteorite

This review presents studies on iron meteorites (Campo del Cielo fall and an unregistered iron meteorite), an unregistered stony meteorite from Northwest Africa, and 13 tektites from the American, European, and Australasian strewn fields. The main experimental technique used in the studies was Mössbauer spectroscopy, both in transmission and backscattering geometries. For the latter, a MIMOS II spectrometer was used. Additionally, optical and scanning electron microscopies and X-ray diffraction were used. In the studied iron meteorites, kamacite is found as the main mineral. Campo del Cielo meteorite exhibits Widmanstätten patterns and schreibersite inclusions. The unregistered iron meteorite has Neumann lines and schreibersite inclusions. We have assigned Campo del Cielo as an octahedrite and the unregistered iron meteorite as a hexahedrite. The unregistered stony meteorite is composed mainly of iron-free silicates; at 4.2 K, the spectrum indicates maghemite and 1% troilite. The Cambodian tektite appeared individualized from other australasites, unlike the moldavite, which tends to cluster with them. Our analyses do not allow dismissing doubts on the provenance of tibetanites. The Fe3+/Fe2+ ratio was found to be higher for Muong Nong-type tektites than for splash-form tektites, as expected from their morphology and solidification from melt at lower temperature.

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