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Chondryt węglisty NWA 4446

Przylibski Tadeusz A., Blutstein Konrad, Łuszczek Katarzyna, Gruchot Joanna

Przegląd Geologiczny

2022

Vol. 70, nr 7

513--526

The authors carried out petrographic, mineralogical, and chemical analyses (bulk chemical composition and microanalyses of mineral chemical composition) of NWA 4446 carbonaceous chondrite. NWA 4446 chondrite is classified as CV3, S2, W2. This meteorite is a rock fragment most likely from one of the C-type asteroids orbiting the Sun in the outer part of the asteroid belt. It represents the matter formed at the earliest stages of the formation of extrasola bodies in the solar system. As a result of the research, the authors documented a wider range of variation in the chemical composition of olivine crystals (Fa: 0.67-46.57 mol%) in the matrix and chondrules, and a much narrower range of variation in the chemical com- position of pyroxene crystals (Fs: 0.90–3.35 mol%) against the data used for the classification of the meteorite. The characteristics of the chondrules, ranging in size from 0.5 to more than 1 mm, allowed concluding that they constitute about 60% of the meteorite’s vol- ume, in which they form many structural and mineral varieties PO, POP, BO, PP and RP chondrules were observed. The remaining 40% of the chondrite volume is a matrix consisting of small crystals of pyroxenes, olivines, glass, as well as opaque minerals: sulphides, FeNi alloy, native copper and gold grains, carbonaceous substance, and compact CAIs. The mineral and chemical composi- tion of CAIs shows that their dominant mineral is melilite, accompanied by diopside and spinel. The chemical composition of spinel and diopside is very similar to their total chemical formulas, while the composition of melilite shows a significant sodium deficiency. Among the opaque minerals, one phase of the FeNi dominates - awaruite (Ni 3 Fe), and sulphides are represented by troilite (FeS) and mackinawite ((Fe,Ni) 9 S 8 ). Moreover, grains of native copper with an admixture of gold and grains of native gold with an admixture of platinum, nickel and copper with a size of several μm were identified. Taking into account the admixtures contained in the above-mentioned opaque minerals (mainly Co and Cu), the parent rock of the carbonaceous chondrite NWA 4446 can be considered to have been mineralized with Fe, Ni, Co and Cu ore minerals with the content of Au and Pt. This means that, we can expect deposits of native forms of the above-mentioned metals and sulphides on the parent bodies of carbonaceous chondrites of the CV group - C-type asteroids.

Perspektywy eksploatacji złóż metali z grupy platynowców z powierzchni asteroid

Kłósko P., Barański K.

Przegląd Górniczy

2017

T. 73, nr 10

1--8

Nieustannie rosnące zapotrzebowanie na surowce metaliczne, w tym metale z grupy platynowców, skłania do poszukiwania nowych, dotychczas niewykorzystywanych źródeł surowców. Potencjalne źródło platynowców stanowią asteroidy znajdujące się w Pasie Planetoid oraz asteroidy z grupy obiektów bliskich ziemi (NEO - ang. Near-Earth Objects). Na podstawie prowadzonych obecnie badań i projektów w dziedzinie eksploracji kosmosu, agencje rządowe i przedsiębiorstwa prywatne opracowują technologie umożliwiające eksploatację złóż platynowców pochodzących z powierzchni asteroid. Biorąc pod uwagę wysokie ceny metali z grupy platynowców oraz ich ograniczone zasoby na Ziemi, pomysł eksploatacji złóż pochodzenia kosmicznego wydaje się uzasadniony ekonomicznie. Istotną kwestią są także aspekty prawne i etyczne, związane z wykorzystywaniem obiektów pozaziemskich w celach gospodarczych.

Constantly growing demand for metallic minerals, including platinum group metals (PGM) stimulates the search for new sources of raw materials, not used yet. The potential sources of PGM are asteroids located in the Asteroid Belt and asteroids from the group of Near-Earth Objects (NEO). On the basis of ongoing researches and projects in the field of space exploration, government agencies and private companies are working on technologies which enable exploitation of PGM from the surface of asteroids. Because of high prices of PGM minerals and their limited resources on Earth, the idea of exploitation of extraterrestrial sources appears to be economically reasonable. Also, the important issue is legal and ethical aspects connected with the use of extraterrestrial objects for economic purposes.