Saumalkol 					Location 53°31.09’N 68°11.05’E
Kazakhstan  
Found 2023, April
Ungrouped chondrite, F-Chondrite  

  
History: The meteorite was found by Mr. Asan Abykeev 25 km NNE from the Saumalkol town,
Aiyrttau district, North Kazakhstan region, Republic of Kazakhstan in April 2023. The meteorite
was discovered near the border a plowed field during a metal detector search for scrap metal. Mr.
Abykeev was tripped over a stone that was sticking out of the ground. He checked the stone with a
metal detector, and since the signal from the stone was very strong, Mr. Abykeev dug up the stone,
and upon closer inspection, he recognized that it is a meteorite.

Physical characteristics: A single stone of 163 kg in weight has a flattened irregular shape. The
reddish-brown surface has coarse regmaglypth.

Petrography: The meteorite has brecciated texture composed of angular rock fragments of 5-10 cm
in size (38 vol. %) surrounded by a main mass (62 vol. %). The metal veins of 0.5-2 cm in thickness
occur on the contacts of the clasts and main mass.
The rock fragments have chondritic texture and are composed of compactly-packed
chondrules, chondrule fragments and mineral grains. The matrix is absent with exception of few
small areas where the very fine-grained pyroxene-feldspar aggregate of irregular texture is
developed between the chondrules. The rock is weakly fractured. The chondrules mostly are not
well lineated. The average chondrule diameter is 410±225 ?m (N=115). The chondrules are of BP,
RP, GO, GOP, POP and CC types. The olivine has weak wavy optical extinction and irregular
fractures. The metal and troilite grains have irregular morphology and usually are occurred
separately from the each other. Minor metal-sulfide aggregates were observed. Modal metal and
troilite abundances are 11.9 and 4.4 vol.% respectively. Accessory minerals are chromite, rutile, Cl-
apatite, schreibersite and native copper. Shreibersite inclusions in Fe,Ni metal have narrow (5 ?m)
taenite rim on the contact with kamacite. Shreibersite aggregated with troilite and metal has no
taenite rim. Chromite is presented by anhedral grains in the main mass of meteorite and by sub- to
euhedral crystals in the Fe,Ni metal. Chromite chondrules and chromite-rich fine-grained objects
were found. The metal is insignificantly replaced by terrestrial Fe,Ni hydroxide.
The main mass contains the chondrule fragments, mineral fragments and complete
chondrules joined together by Fe,Ni metal (16.0 vol.%) and troilite (5.3 vol.%). The metal and
troilite are heterogeneously distributed in the main mass of meteorite and form irregular grains and
clumps (up to 5 mm in size) having ~50 vol.% of metal witn inclusions of chondrules and silicate
grains. The metal veins up to 5 cm in length are present in the main mass.

Mineral compositions and geochemistry: (Borisovsky S.E., IGEM RAS, EPMA): Olivine
Fa4.36±0.17 (here and further in wt.%: CaO 0.02±0.02; Cr2O3 0.03±0.02; N=20) Low-Ca
pyroxene: Fs5.57±1.25 Wo1.85±1.58 (Al2O3 0.42±0.35; TiO2 0.11±0.07; Cr2O3 0.37±0.26;
N=29); Fs7.71±1.75 Wo6.42±1.71 (Al2O3 1.00±0.46; TiO2 0.12±0.04; Cr2O3 0.76±0.21; N=12);
diopside Fs2.90±1.12 Wo38.46±9.99 (Na2O 0.58±0.32; Al2O3 2.52±1.91, TiO2 0.12±0.04; Cr2O3
1.27±0.40; N=21); Chromite MgO 8.51±0.31; Al2O3 5.31±0.12; V2O3 0.6±0.07; TiO2 0.26±0.15;
ZnO 0.28±0.02 (N=11); Kamacite: Ni 6.14±0.32; Co 0.41±0.02; Si 0.02±0.01 (N=10); Taenite Ni
38.46±5.4; Co 0.18±0.06; Si 0.04±0.01 (N=10); Troilite (Cr 0.26±0.02; N=11); Oxygen isotopic
composition (J. Gattacceca, C. Sonzogni, D. Au Yang, CEREGE) is d17O=2.72‰, d18O=4.17‰ ,
D17O=0.56‰; Magnetic susceptibility measured on 6.59 g is logX = 5.41 (J. Gattacceca CEREGE).

Classification: Based on high-MgO silicate composition out of the H chondrites range, absence of
matrix and specific oxygen isotope composition the meteorite is classified as ungrouped chondrite
of petrological Type 4, weakly shocked (S2) and weakly weathered (W1). The meteorite can have
an affinity to “F-chondrites” by MgO-rich composition of silicates and oxygen isotopic composition
which is between H and “F” chondrite trends, near Acfer 370 “F”-chondrite composition. The Cr
abundance in troilite of Saumalcol is close to that of Acfer 370.