Meteoryt Pułtusk 1868 / Pultusk meteorite 1868

Meteorite Pultusk, January 30, 1868
Selected specimens from the collection of the Faculty of Geology, Warsaw University

The meteorite fall ocurred on the January 30, 1868, in the vicinity of the town of Pultusk, NE from Warsaw. The area of the fall was 127 km². The estimated total mass of the meteorites reached 8,863 kg and the number of the fragments counted 68,780. Most of the fragments had the mass of few gram, they have been called "the Pultusk peas". The largest found specimen weighted 9,095 g (J. Samsonowicz 1953).


#008814 - loc. Gostkowo, specimen from the collection of the Mineralogical Cabinet of the Main School in Warsaw	#002932 - loc. Magnuszew, coll. Jan Samsonowicz, specimen bought from W. Borowinska 4.VIII.1951, mass 18,6g	#008810 - specimen from the materials of K. Smulikowski, mass 254,9g

#008811 - specimen from the materials of K. Smulikowski, mass 81,7g	#008813 - specimen from the materials of K. Smulikowski, mass 102,9g	#008815 - specimen from the materials of K. Smulikowski, mass 96,3g

#008818 - specimen from the materials of K. Smulikowski, mass 33,5g	#008821 - specimen from the materials of K. Smulikowski, mass 44,5g	#008826 - specimen from the materials of K. Smulikowski, mass 12,2g

#008834 - ospecimen from the materials of K. Smulikowski, mass 14,5g	#008872 - specimen from the materials of K. Smulikowski, mass 11,2g	"Pultusk peas" - specimens from the materials of K. Smulikowski, mass 3,9 - 2,2g

Materials from the licentiate dissertation of Joanna Szczygielska (Institute of Geochemistry, Mineralogy and Petrology, Faculty of Geology, Warsaw University), made under supervision of Andrzej Pelc, M.Sc. in 2002.

     Studies of the meteorite Pultusk concern a very variable material of the large amount of small fragmests, thus the generalised characteristics is rather difficult. The meteorite is brecciated and contains two varieties of xenoliths embedded in dark brecciated groundmass. R. A. Binns (fide A. Manecki 1972) determined the groundmass as a primary component and xenoliths as the recrystallised ones. During the microscope studies A. Manecki (1972) found fissures healed by opaque minerals.
     The better crystallised xenoliths bear small amount of olivine and pyroxene chondrules, in part damaged and crushed. The pyroxene chondrules are excentric-radial but the olivine ones consist of parallel arranged olivines. The groundmass bears olivine in fine- to medium-grained aggregates and opaque minerals, moreover rare plagioclase. The boundary between chondrules and the groundmass is indistinct.
     The xenoliths of the lower degree of recrystallisation bear more chondrules than the xenoliths of the former type. The chondrules have spherical and ellipsoidal shape, but frequently one may find only their fragments. They are distinctly separated from the groundmass. For the olivine chondrules the boundary is marked by droplets of the opaque minerals. The chondrules consist of platy olivine and prismatic pyroxene, their texture is excentric-radial. The chondrules of the granular structure are built from olivine as well. Condrules formed by single olivine grains have been found as well; the chondrules of the parallel textures and those formed in their central partz by parallel olivine aggregate and surrounded by granular mass of the same mineral are distinctly rarer. Space between the plates of olivine or small prisms of pyroxene is filled by partly recrystallised maskelynite.
     The meteorite Pultusk is a brecciated chondrite with abundant xenoliths of various degrees of recrysdtallisation. Olivine and bronzite are the main minerals, kamacite, troilite and chromite are subordinate, chalcopyrite, plagioclase and native copper are accesory mierals.
     The chondrules consist of olivine and bronzite. According to the B. Mason's (1962) classification, the meteorite Pułtusk is the olivine-bronzite chondrite type H. Xenoliths of the type five prevail in it, according to the petrologic classification proposed by W. R. van Schmus and J. A. Wood (1967). Thus, the meteorite Pułlusk has the symbol H5,that means it is the ordinary chondrite significantly metamorphosed thermally, because the contours of the chondrules frequently are difficult to distinguish (A. Manecki 1972).

Meteorite iron, kamacite – occurs as gray grains of various shape and size, of the xenomorphic habit, frequently dendritic. Grains of the size of few millimetres ar most common. In some specimens iron occurs in veilets up to 20 mm long. The largest mass of a single grain was 25,86g. Density of kamacite equals to 6,916 g/cm³.
Troilite – forms xenomorphic fractured grains. Occurs with kamacite and as inclusions in this mineral.
Chalcopyrite – appears rarely, occurs with troilite.
Chromite – occurs relatively rarely as inclusions in silicate minerals, its grains are xenomorphic. In asociation wit kamacite it is hypidiomorphic, sometimes in envelopes of kamacite or troilite, foreming the atol structures. In o;ivine chromite forms exsolution inclusions.
Native copper – forms tiny xenomorphic inclusions in kamacite.
Olivine – that one occurring in the meteorite Pultusk contains 17 -18 mol. % fayalite. It is a component of the chondrules and in lesser degree it occurs in the groundmass.
Pyroxene – bronzite, a component of the chondrules and in subordinate amounts it is present in the groundmass.
Plagioclases – xenomorphic grains with albite twinning.
Maskelynite – transparent with low refractive indices and undulous anomal light extinction.
The mineral composition is ghiven according to A. Manecki (1973). Other authors mentioned also anorthite, clinobronzite, enstatite and diallag.

The chemical composition and the results of calculations given according to Diakonov and Kharitonova (1961). Contents in weight percent.

SiO2	36.44
TiO2	0.18
Al2O3	1.88	Fe (metallic)	17.62
Cr2O3	0.37
FeO	9.48	Ni in meteorite iron	9.13
MnO	0.25
MgO	23.75	Fe as iron sulphide	3.80
CaO	1.82
Na2O	0.83	S as iron sulphide	2.17
K2O	0.09
P2O5	0.22	Total content of iron	27.19
Fe	16.02
Ni	1.61
FeS	5.97
Total	98.91