Mineralogy, petrography, geochemistry, and classification of the Košice meteorite

Abstract

The Ko sice meteorite was observed to fall on 28 February 2010 at 23:25 UT near the city of Ko sice in eastern Slovakia and its mineralogy, petrology, and geochemistry are described. The characteristic features of the meteorite fragments are fan-like, mosaic, lamellar, and granular chondrules, which were up to 1.2 mm in diameter. The fusion crust has a black-gray color with a thickness up to 0.6 mm. The matrix of the meteorite is formed mainly by forsterite (Fo 80.6 ); diopside; enstatite (Fs 16.7 ); albite; troilite; Fe-Ni metals such as iron and taenite; and some augite, chlorapatite, merrillite, chromite, and tetrataenite. Plagioclase-like glass was also identified. Relative uniform chemical composition of basic silicates, partially brecciated textures, as well as skeletal taenite crystals into troilite veinlets suggest monomict breccia formed at conditions of rapid cooling. The Ko sice meteorite is classified as ordinary chondrite of the H5 type which has been slightly weathered, and only short veinlets of Fe hydroxides are present. The textural relationships indicate an S3 degree of shock metamorphism and W0 weathering grade. Some fragments of the meteorite Ko sice are formed by monomict breccia of the petrological type H5. On the basis of REE content, we suggest the Ko sice chondrite is probably from the same parent body as H5 chondrite Mor avka from Czech Republic. Electron-microprobe analysis (EMPA) with focused and defocused electron beam, whole-rock analysis (WRA), inductively coupled plasma mass and optical emission spectroscopy (ICP MS, ICP OES), and calibration-free laser induced breakdown spectroscopy (CF-LIBS) were used to characterize the Ko sice fragments. The results provide further evidence that whole-rock analysis gives the most accurate analyses, but this method is completely destructive. Two other proposed methods are partially destructive (EMPA) or nondestructive (CF-LIBS), but only major and minor elements can be evaluated due to the significantly lower sample consumption.

An Innovative Approach to Meteorite Analysis by Laser‐Induced Breakdown Spectroscopy

“…The presence of Cu can be ascribed to a miscibility gap that often occurs between taenite (γ‐(Ni, Fe) and two other metal phases, i.e., kamacite and tetrataenite (tetragonal taenite), where Fe + Co ↔ Ni + Cu substitutions may occur (Ozdin et al . ). The additional elements detected by LIBS only in the external regions of the whole meteorite in the wavelength range 6310–6750 Å (Figure c), i.e., Ca (6439 and 6471 Å), Ga (6334 Å), and Li (6707 Å) might also be ascribed to alteration processes.…”

“…A further study (Ozdin et al . ) identified this meteorite as a monomict breccia of the petrological type H5, thus suggesting that the Košice chondrite probably originates from the same parent body of the H5 chondrite Morávka from the Czech Republic.…”

Cosmogenic radionuclides and mineralogical properties of the Chelyabinsk (LL5) meteorite: What do we learn about the meteoroid?

“…The total abundance of the major oxides was determined in sample No. 4 by classic whole-rock analysis and inductively coupled plasma-emission spectrometry (ICP-ES) (Ozd ın et al 2015). In addition, some major and trace element abundances were analyzed in samples No.…”

Variations of cosmogenic radionuclide production rates along the meteorite orbits

“…As pointed out, the cosmogenic radionuclides were produced from all target elements of the Chelyabinsk and Košice compositions (Ozdín et al, 2015;Galimov et al, 2013). An essential problem is the determination of the specimen locations inside meteorites.…”

“…Even in the same chemical group of the chondrites, the chemical composition of the individual ones may be rather different. Therefore, analyzing cosmogenic radionuclides in a chondrite, its individual content of the main element composition must be used, e.g., the chemical compositions of the Košice and Chelyabinsk chondrites, presented by Ozdín et al (2015), and Galimov et al (2013) were used here. The contribution of a target element on the production of a radionuclide depends on its content in the chondrite, as well as on the average production cross sections of the radionuclide with primary and secondary nuclear active particles, which are the highest for the nearby target elements.…”