Mineral and chemical composition of the Jezersko meteorite—A new chondrite from Slovenia

The Jezersko meteorite is a newly confirmed stony meteorite found in 1992 in the Karavanke mountains, Slovenia. The meteorite is moderately weathered (W2), indicating short terrestrial residence time. Chondrules in partially recrystallized matrix are clearly discernible but often fragmented and have mean diameter of 0.73 mm. The meteorite consists of homogeneous olivine (Fa_19.4) and low‐Ca pyroxenes (Fs_16.7Wo_1.2), of which 34% are monoclinic, and minor plagioclase (Ab₈₃An₁₁Or₆) and Ca‐pyroxene (Fs₆Wo_45.8). Troilite, kamacite, zoned taenite, tetrataenite, chromite, and metallic copper comprise about 16.5 vol% of the meteorite. Phosphates are represented by merrillite and minor chlorapatite. Undulatory extinction in some olivine grains and other shock indicators suggests weak shock metamorphism between stages S2 and S3. The bulk chemical composition generally corresponds to the mean H chondrite composition. Low siderophile element contents indicate the oxidized character of the Jezersko parent body. The temperatures recorded by two‐pyroxene, olivine‐chromite, and olivine‐orthopyroxene geothermometers are 854 °C, 737–787 °C, and 750 °C, respectively. Mg concentration profiles across orthopyroxenes and clinopyroxenes indicate relatively fast cooling at temperatures above 700 °C. A low cooling rate of 10 °C Myr^?1 was obtained from metallographic data. Considering physical, chemical, and mineralogical properties, meteorite Jezersko was classified as an H4 S2(3) ordinary chondrite.     

The Yarle Lakes 001 meteorite: A H5 chondrite from South Australia

Abstract— The Yarle Lakes 001 meteorite was a single stone of 913 g found approximately 20 km north of Watson, South Australia, in 1990 October. It consists of olivine (Fa_{18.7 ± 0.4}, n = 30), low-Ca pyroxene (Fs_{16.6 ± 0.2} Wo _{12 + 0.4}, n = 15). feldspar, high-Ca pyroxene, metallic Fe-Ni and troilite. Based on texture and mineral chemistry, Yarle Lakes 001 is classified as a H5 chondrite of shock stage S3.     

The Danebury Iron Age meteorite—An H5 ordinary chondrite “find” from Hampshire,England

What remains of a 30 g sample, first recognized as a meteorite in 1989 during characterization of metalworking debris from Danebury, an Iron Age hillfort, in Hampshire, England, has been classified as an H5 ordinary chondrite. Its arrival on Earth has been dated as 2350 ± 120 yr BP, making it contemporary with the period of maximum human activity at the recovery site. Despite its considerable terrestrial residence age, the interior of the specimen is remarkably fresh with a weathering index of W1/2. There is, however, no evidence of human intervention in its preservation. Its near‐pristine state is explained in terms of its serendipitous burial during the back‐fill of a pit dug into chalk by prehistoric people for the storage of grain. This chance discovery has interesting ramifications for the survival of meteorites in areas having a high pH because of a natural lime content arising as a result of the local geology.     

The Loxton meteorite: A new olivine-bronzite chondrite from South Australia

Abstract— The Loxton meteorite is a single stone of 22 g found in South Australia in 1968. It has been classified as an L5 chondrite, shock facies ‘a,’ and contains olivine (Fa₂₄), orthopyroxene (Fs_21–22), clinopyroxene (Wo_44.7En_45.9Fs_9.4), nickel-iron, troilite, chromite and chlorapatite.     

Denman 002: A new CV3 chondrite from South Australia

Abstract— Denman 002 is a new Australian carbonaceous chondrite. A single stone of 30 g was recovered in 1991 May near Fisher Station on the Trans Australian Railway, Nullarbor Plain, South Australia (30°36′S, 130°04′E). Texture, mineral and chemical composition indicate that it is a CV3 chondrite of oxidised subgroup with several similarities to Allende. It is composed of sharply defined chondrules, Ca-Al rich inclusions up to 3.5 mm across, olivine aggregates and fine-grained, nearly opaque matrix (40 vol%). Silicates are compositionally highly heterogeneous (olivine Fa: 0.2–45.6 mol%, PMD: 109.7). Denman 002 shows shock effects of stage SI and weathering of category A.     

Ejby—A new H5/6 ordinary chondrite fall in Copenhagen,Denmark

On February 6, 2016 at 21:07:19 UT, a very bright fireball was seen over the eastern part of Denmark. The weather was cloudy over eastern Denmark, but many people saw the sky light up—even in the heavily illuminated Copenhagen. Two hundred and thirty three reports of the associated sound and light phenomena were received by the Danish fireball network. We have formed a consortium to describe the meteorite and the circumstances of the fall and the results are presented in this paper. The first fragment of the meteorite was found the day after the fall, and in the following weeks, a total of 11 fragments with a total weight of 8982 g were found. The meteorite is an unbrecciated, weakly shocked (S2), ordinary H chondrite of petrologic type 5/6 (Bouvier et al. 2017). The concentration of the cosmogenic radionuclides suggests that the preatmospheric radius was rather small ~20 cm. The cosmic ray exposure age of Ejby (83 ± 11 Ma) is the highest of an H chondrite and the second highest age for an ordinary chondrite. Using the preatmospheric orbit of the Ejby meteoroid (Spurny et al. 2017) locations of the recovered fragments, and wind data from the date of the fall, we have modeled the dark flight (below 18 km) of the fragments. The recovery location of the largest fragment can only be explained if aerodynamic effects during the dark flight phase are included. The recovery location of all other fragments are consistent with the dark flight modeling.     

The Wilder H5 chondrite: A 1982 find from Idaho

Abstract— The Wilder chondrite, a single stone of 1970 g, was found in southwestern Idaho in 1982. A classification of H5 is indicated by the mean compositions of olivines (Fa_18.4) and orthopyroxenes (Fs_16.3), and the narrow range in mineral compositions, recrystallized nature of the matrix, and mean Wo content of the orthopyroxenes (Wo_1.34).     

Nullarbor 018: A new L6 chondrite from Australia

Abstract— A new meteorite find from the Nullarbor Plain in Australia was studied using optical, SEM, and electron microprobe techniques. The meteorite, Nullarbor 018, is an orthodox L6 chondrite that experienced minor-to-moderate alteration of metal during terrestrial weathering (grade A–B to B). During weathering, troilite was preferentially altered, and roughly 20% of the original complement of S in the meteorite was removed. Shock metamorphic effects corresponding to shock stage S4 (or shock facies d) are found, including the presence of some diaplectic feldspar (maskelynite). The meteorite is not obviously paired with other finds from the Nullarbor region, but the possibility that it is paired cannot be excluded.     

Lake Machattie,a weathered H5 chondrite find from Queensland,Australia

Abstract— Lake Machattie is an H5a chondrite find. The 2.6-kg stone is heavily weathered; unoxidized metal occurs only as 10-μm-size blebs enclosed in olivine.     

The Galkiv meteorite: A new H4 chondrite from Ukraine

Abstract— The Galkiv chondrite is a single 5 kg stone that fell in the Chernigov region of Ukraine on 1995 January 12. The composition of olivines in the meteorite indicate that Galkiv belongs to the H group of ordinary chondrites. Although the heterogeneity of olivine corresponds to a petrologic type 5 and the heterogeneity of low-Ca pyroxene suggests the chondrite is type 3, clearly defined chondrule boundaries, the presence of clinopyroxene, cryptocrystalline glass and rare grains of feldspatic plagioclase, structural evidences of shock metamorphism and very low level of terrestrial weathering allow us to classify the meteorite as an H4 chondrite of shock stage S3 and weathering grade WO.     

Rumanová H5 chondrite,Slovaki

Abstract— An H5 chondrite was found near the village of Rumanová, Slovakia. dominant minerals of the meteorite are enstatite, olivine, kamacite, taenite and troilite. The minor minerals are oligoclase, augite, pigeonite, accessory chromite, whitlockite and chlorapatite. The composition of olivine (Fa_19.0) and low-Ca orthopyroxene (Fs_17.0), and the density and chemical composition of the meteorite correspond to those of an H chondrite. Normal zoning of Ni in metal grains and parallel planar fractures in olivine suggest weak shock metamorphism of stage S3. Due to moderate oxidation of metal, iron hydroxides were formed corresponding to weathering stage W2.     

The nuclear track record of core samples from the H5 chondrite Jilin

Abstract— Based on 43 documented drill core samples of the H5 chondrite Jilin, the depth profile of track densities was investigated. The study of olivine and pyroxene crystals extracted from the two drill cores A and B of the main fragment no. 1 yields a track background for the Jilin interior of 150 ± 90 cm^?2. To estimate the contribution of different track origins, the U microdistribution of sample sections and single grain sections was mapped by neutron-induced ²³⁵U-fission using high-purity quartz glass detectors. The average U content of 0.59 ± 0.22 ppb for pyroxenes and 0.12 ± 0.06 ppb for olivines is consistent with the observed fission track background in these minerals. There are no indications of spontaneous fission of ²⁴⁴Pu, secondary mobilisation of U in the bulk sample, or substantial track annealing. As deduced from the calculated fission track density, the track contribution from galactic cosmic rays is negligible in the core samples investigated.     

Tabbita: An L6c chondrite from New South Wales,Australia

Abstract— A crusted stone weighing 3.10 kg was found in 1983 near Tabbita in south central New South Wales (ca. 34°03′S, 145°50′E), Australia. Compositions of the ferro-magnesian silicates (olivine Fa_24.6; orthopyroxene Fs_20.9) show that the meteorite belongs to the L-group of chondrites. Uniformity of silicate compositions and the presence of abundant crystalline plagioclase feldspar (An_10.8Ab_81.7Or_7.5) show that the meteorite belongs to petrologic type 6. Silicates that display undulose extinction, and the absence of any thermal effects induced by shock indicate that Tabbita is shock facies c. Tabbita is distinct from several other L6 chondrites found in the same general area.     

The Iguaraçu H5 chondrite: a fall from Paraná State,Brazil

Abstract— The Iguaraçu meteorite, a single stone of 1200 g, fell in Paraná State, Brazil in October 1977. It is classified as an H5 ordinary chondrite with olivine of composition Fa 18.7.     

Petrology and mineralogy of the Ningqiang carbonaceous chondrite

Abstract— We report detailed chemical, petrological, and mineralogical studies on the Ningqiang carbonaceous chondrite. Ningqiang is a unique ungrouped type 3 carbonaceous chondrite. Its bulk composition is similar to that of CV and CK chondrites, but refractory lithophile elements (1.01 × CI) are distinctly depleted relative to CV (1.29 × CI) and CK (1.20 × CI) chondrites. Ningqiang consists of 47.5 vol% chondrules, 2.0 vol% Ca,Al‐rich inclusions (CAIs), 4.5 vol% amoeboid olivine aggregates (AOAs), and 46.0 vol% matrix. Most chondrules (95%) in Ningqiang are Mg‐rich. The abundances of Fe‐rich and Al‐rich chondrules are very low. Al‐rich chondrules (ARCs) in Ningqiang are composed mainly of olivine, plagioclase, spinel, and pyroxenes. In ARCs, spinel and plagioclase are enriched in moderately volatile elements (Cr, Mn, and Na), and low‐Ca pyroxenes are enriched in refractory elements (Al and Ti). The petrology and mineralogy of ARCs in Ningqiang indicate that they were formed from hybrid precursors of ferromagnesian chondrules mixed with refractory materials during chondrule formation processes. We found 294 CAIs (55.0% type A, 39.5% spinel‐pyroxene‐rich, 4.4% hibonite‐rich, and several type C and anorthite‐spinel‐rich inclusions) and 73 AOAs in 15 Ningqiang sections (equivalent to 20 cm²surface area). This is the first report of hibonite‐rich inclusions in Ningqiang. They are texturally similar to those in CM, CH, and CB chondrites, and exhibit three textural forms: aggregates of euhedral hibonite single crystals, fine‐grained aggregates of subhedral hibonite with minor spinel, and hibonite ± Al,Ti‐diopside ± spinel spherules. Evidence of secondary alteration is ubiquitous in Ningqiang. Opaque assemblages, formed by secondary alteration of pre‐existing alloys on the parent body, are widespread in chondrules and matrix. On the other hand, nepheline and sodalite, existing in all chondritic components, formed by alkali‐halogen metasomatism in the solar nebula.     

Korra Korrabes: A new,large H3 chondrite breccia from Namibia

Abstract— A new, large, ordinary chondrite has been recovered from near the strewn field of Gibeon iron meteorites in Namibia, and is designated Korra Korrabes, after the farm property on which the specimens were found in 1996–2000. A total of ～140 kg of related specimens were recovered, including a large stone of 22 kg, and hundreds of smaller objects between 2 g and several kilograms. Cut surfaces indicate that Korra Korrabes is a breccia, containing 10–20% of light grey‐brown clasts up to 3 cm across in a uniform, darker grey‐brown host that contains abundant round chondrules, and irregular grains of Fe‐Ni metal and troilite up to 1 cm across. The vast majority of the stone is unshocked, although some clasts show mild shock features (stage S2), and one chondrule fragment is moderately shocked (stage S3). Weathering grade varies between W1 and W2. Microprobe analyses indicate variable compositions of olivine (Fa_13.8–27.2, n = 152, percent mean deviation = 7.82%) and low‐Ca pyroxene (multiply twinned clinobronzite, Fs_8.4–27.8, n = 68). There is excellent preservation of magmatic textures and mineralogy within many chondrules, including normally zoned olivine (Fa_13.8–18.9) and low‐Ca pyroxene (Fs_0.2–20.9) phenocrysts, and abundant glass, some of whose compositions are unusually alkaline (Na₂O + K₂O = 13.6–16.3 wt%) and Ca‐deficient (CaO = 0‐0.75 wt%), seemingly out of magmatic equilibrium with associated clinoenstatite or high‐Al calcic clinopyroxene crystals. Textural and mineralogical features indicate that Korra Korrabes is an H3 chondrite breccia, which represents the largest and least equilibrated stony meteorite yet recovered from Namibia; it is now one of the four largest unequilibrated ordinary chondrites worldwide.     

The Cali meteorite fall: A new H/L ordinary chondrite

Abstract— The fall of the Cali meteorite took place on 6 July 2007 at 16 h 32 ± 1 min local time (21 h 32 ± 1 min UTC). A daylight fireball was witnessed by hundreds of people in the Cauca Valley in Colombia from which 10 meteorite samples with a total mass of 478 g were recovered near 3°24.3′N, 76°30.6′W. The fireball trajectory and radiant have been reconstructed with moderate accuracy. From the computed radiant and from considering various plausible velocities, we obtained a range of orbital solutions that suggest that the Cali progenitor meteoroid probably originated in the main asteroid belt. Based on petrography, mineral chemistry, magnetic susceptibility, thermoluminescence, and bulk chemistry, the Cali meteorite is classified as an H/L4 ordinary chondrite breccia.     

The Juancheng chondrite: A new meteorite fall from China

Abstract— A new meteorite, the Juancheng chondrite, fell recently in Juancheng County, Shandong Province, China. It is classified as an H5 (S2) chondrite on the basis of the compositions of olivine (Fa 19.2, σ_Fa 0.46), low-Ca pyroxene (Fs 16.9, σ_Fs 0.4) and Co contents of kamacite (0.36–0.47 wt%). Plagioclase is compositionally heterogeneous.