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Błasiak Aleksander, (2026), Petrologia, mineralogia i geochemia pierwiastków śladowych meteorytu Drelów (Petrology, mineralogy and trace element geochemistry of the Drelów meteorite), Acta Soc. Metheor. Polon., 17, 2026, s. 35-51 (abstrakt). Plik doi; plik ASMP.

Abstract: On 18 February 2025, a bright fireball was observed over eastern Poland and recorded by the Skytinel fireball network.^[1] Subsequent field searches led to the recovery of the Drelów meteorite, already classified as a L6 ordinary chondrite, with a shock stage of S3 and a terrestrial weathering grade of W0. The total recovered mass amounts to approximately 3900 g. One specimen, independently found by the author, was selected for detailed petrographic, mineralogical and geochemical investigation. The meteorite is characterised by a predominance of a xenomorphic matrix with scarce relic chondrules, reflecting advanced thermal metamorphism. Numerous shock veins are present throughout the samples, locally filled with secondary Fe oxides and hydroxides. The fusion crust is porous and locally contains small spinel grains (<10 μm). Optical microscopic observations combined with electron microprobe analyses indicate that the silicate assemblage is dominated by olivine and low-Ca pyroxene, accompanied by feldspar, Fe-Ni metal phases, troilite, chromite and accessory phosphates. Metallic phases include kamacite, taenite and tetrataenite, with average Ni and Co contents of ~5.9 wt.% Ni and ~0.95 wt.% Co in kamacite, ~28.9 wt.% Ni and ~0.38 wt.% Co in taenite, and ~50.7 wt.% Ni and ~0.16 wt.% Co in tetrataenite. Troilite is predominantly stoichiometric, contains trace amounts of Co (up to 0.08 wt.%), and native copper was observed as an accessory phase. Mean silicate compositions correspond to Fo₇₅Fa₂₅ in olivine and Wo_1.6En_77.5Fs_20.9 in pyroxene. Trace element concentrations were determined using LA-ICP-MS and are presented as chondrite-normalised spider diagrams for individual mineral phases, including olivine, pyroxene, feldspar, apatite and merrillite. Olivine and pyroxene preserve the most coherent primary geochemical signature, whereas phosphates represent the principal hosts of rare earth elements, with merrillite showing systematically higher REE abundances than apatite, because of its low-temperature origin. Comparison of chromite compositions from the sample with ophiolitic chromites normalised to MORB highlights elevated Ti and depleted Ni and Co contents in meteoritic chromites, reflecting preferential partitioning of Ni and Co into metallic phases in chondritic material. The combined microscopic observations and chemical analyses confirm the L6 (S3/W0) classification of the Drelów meteorite and demonstrate that a phase-selective analytical approach provides robust constraints on the distribution of trace elements and REE carriers, offering greater insight than whole-rock analyses.

Keywords: Drelów, trace elements, spider diagrams, ordinary chondrite, merrillite, chromite

(Opisy ilustracji w haśle Drelów/Badania)

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