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Wyniki badań mineralogicznych i petrologicznych nowych okazów meteorytu Pułtusk w 150 rocznicę spadku

Przylibski T. A., Łuszczek K.

Przegląd Geologiczny

2018

Vol. 66, nr 6

368--378

One of the largest observed stone meteorite shower in the history of mankind on Earth took place on Thursday evening on January 30, 1868, about seven o’clock near Pułtusk in Poland. Despite the 150th anniversary of the fall of chondrite officially classified as Pułtusk H5 with a shock stage S3 there is still little published data on the chemical composition of minerals of this chondrite as well as its petrological characteristics in the literature. The authors carried out mineralogical and petrological research that will help a little to fill this gap in knowledge about the Pułtusk chondrite. Meteorite specimens found by Piotr Kuś in 2015 and investigated by the authors are undoubtedly part of the Pułtusk fall of January 30, 1868. They can be classified as ordinary chondrite H5, S2,W2. The authors stated that the studied rock is characterized by a varied shock level -from S1 to S2/3, as well as it contains chondrules of the chromite-plagioclase unequilibrated rock. In the composition of the examined fragment of Pułtusk chondrite, the authors identified silicates: olivine, diopside, bronzite and clinohyperstene, and oligoclase, oxides: chromite (and spinel), sulfides: troilite, FeNi alloy mineral phases: kamacite and taenite, as well as phosphates: merrilite and apatite. The chemical composition of olivine crystals as well as low- and high-Ca pyroxenes crystals and plagioclase crystals (about the composition of oligoclase) confirms that the examined specimen comes from the Pułtusk fall and it is a rock that should be classified as a petrographic type H5.

Shock veins in the Sahara 02500 ordinary chondrite

Owocki Krzysztof, Muszyński Andrzej

Geologos

2012

Vol. 18, No. 2

111--118

A specimen of the Sahara 02500 ordinary chondrite contains shock-produced veins consisting of recrystallised fine-grained pyroxenes that include small droplets of Ni-rich metal. Non-melted olivines and pyroxenes show planar deformations filled by shock-melted and -polluted metal and troilite. Shock-melted feldspathic glass is present close to the shock veins. Geothermometric estimations indicate that the meteorite locally experienced moderate shock metamorphism with a minimum local peak temperature above 1400ºC, resulting in partial melting of Ca-poor pyroxene and full melting of feldspars, metal and sulphides. The mineral assemblage in the shock veins suggests a pressure during melt recrystallisation below 10 GPa.