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1

Noble gases in Baszkówka and Mt. Tazerzait

Scherer P., Schultz L.

Geological Quarterly

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2001

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Vol. 45, No 3

313-314

EN

Concentration and isotopic composition of noble gases have been measured in bulk samples of the L5 chondrites Baszkówka and Mt. Tazerzait. Compared to other chondrites both meteorites have very large cosmic-ray exposure ages of 74 and 60 million years, respectively. During their history both meteorites were not involved in major thermal events.

2

K/Ar dating and stable isotope analysis of the Baszkówka and Mt. Tazerzait L5 chondrites

Hałas S., Wójtowicz A.

Geological Quarterly

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2001

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Vol. 45, No 3

315-318

EN

We have determined the content of 40Ar* (1.49 nmol/g) and 4He (1.75 nmol/g) in the Baszkówka meteorite by static vacuum mass spectrometry. The radiogenic argon content was calculated from the measured argon spectrum using the equation: 40Ar* = 40Ar - 295.536Ar assuming a potassium content of 680 ppm wgt. We have obtained K/Ar ages of 3.78 Ga for the chondrules and 3.47 Ga for a bulk sample of Baszkówka. A similar 4He content (1.47 nmol/g) but larger 40Ar* (2.32 nmol/g) content was found for the Mt. Tazerzait bulk sample. The K/Ar age of this meteorite on the basis of the K content (732 ppm) is 4.34 Ga. Sulphur isotope analysis of troilite specimens from both meteorites reveals essentially negative delta 34S values: -1.25š0.06o/oo for Baszkówka and -1.18š0.06o/oo for Mt. Tazerzait expressed on the V-CDT scale. This indicates that both chondrites may have a common origin. The oxygen isotope data (delta 18O = 4.88š0.03o/oo and delta 17O = 3.66š0.10o/oo) suggests that Baszkówka belongs to the L chondrites.

3

Euhedral crystals in interstitial pores of the Baszkówka and Mt. Tazerzait L5 chondrites

Wlotzka F., Otto J.

Geological Quarterly

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2001

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Vol. 45, No 3

257-262

EN

Euhedral to anhedral crystals of the main meteoritic minerals are found in interstitial pores of the unshocked L5 chondrites Baszkówka and Mt. Tazerzait. The composition of these pore minerals is the same as elsewhere in the meteorite. They must have grown from a vapour phase during metamorphic equilibration of the meteorite minerals. The pores are primary features, i.e. open space remaining after compaction of the constituents of the meteorite.

4

A study on chemical composition of Baszkówka and Mt. Tazerzait chondrites

Dybczyński R., Chwastowska J., Danko B., Kulisa K., Polkowska-Motrenko H., Samczyński Z., Sterlińska E., Szopa Z.

Geological Quarterly

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2001

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Vol. 45, No 3

289-302

EN

The elemental contents of two new meteorites, Baszkówka (Poland, 1994) and Mt.Tazerzait (Niger, 1991), were studied by instrumental and radiochemical neutron activation analysis (NAA), supplemented in the case of some elements by gravimetric, titrimetric, spectrophotometric and atomic absorption spectrometric measurements. In total 28 elements were determined for each meteorite. A striking similarity in the bulk chemical composition of the two meteorites was observed. In the case of Baszkówka some study of the elemental contents of the magnetic fraction and the distribution of elements between kamacite and taenite phases was also made. This study confirms that Baszkówka and Mt. Tazerzait are generally more similar to L chondrites than to any other class of chondrites. However both meteorites show also some distinctive features (e.g very low Hg content), distinguishing them from all other L chondrites known. Both meteorites may derive from a common parent body, which may be different from that typical for other chondrites.