[meteorite-list] Met Bulletin Update - Braunschweig Approved - April 23, 2013 Fall

From: Galactic Stone & Ironworks <meteoritemike_at_meteoritecentral.com>
Date: Mon, 23 Sep 2013 15:39:58 -0400
Message-ID: <CAKBPJW8tqR-g+c-_XSdJSWj7jqi95Ea8EGGsGhGmc7T+npJYLw_at_mail.gmail.com>

Hi Bulletin Watchers,

Lost in all of the excitement about Chelyabinsk was the 04-23-13 fall
of the Braunschweig L6 meteorite in Germany.

Link - http://www.lpi.usra.edu/meteor/metbull.php?code=58083

Write-up :

Braunschweig 52?13.548?N, 10?31.193?E
Niedersachsen, Germany
Fell: 2013 Apr 23, 02:05 a.m.
Classification: Ordinary chondrite (L6)

History: (R. Bartoschewitz, Bart) Erhard Seemann recognized a rock
impact in the concrete pavement in his yard 3 m from his front door
when he came home on April 23, 2013, in the morning. He documented his
observation and collected the main fragments (~700 g) of the nearly
complete crushed stone. A neighbor heard a strong hum followed by a
loud crash that night at about 2:10 a.m. In the morning he found
several small rock fragments (~50 g) in his gateway. In Ahlum village,
Julian Mascow was surprised by a bright flare coming from the SE,
ending in a short tracer just over his head. About 90 s later he was
frightened by an explosion and ensuing rattling sound around him. Mark
Vornhusen?s web camera documented the fireball from Vechta. When
Rainer Bartoschewitz documented the meteorite impact, he discovered
many further small fragments (~500 g) within 18 m of the others.

Physical characteristics: (R. Bartoschewitz, Bart) One meteorite
individual of about 1.3 kg broken into hundreds of small fragments
after impacting concrete pavement. The biggest fragment, 214 g, stuck
in the concrete making a 7 cm diameter, 3 cm deep impression. Other
fragments were <30 g. The gray-white meteorite material is covered by
a 0.4 mm thick dull black fusion crust with abundant 50 ?m cracks.
Magnetic susceptibility log ? = 4.75.

Petrography: (R. Bartoschewitz, Bart) Recrystallized matrix of
olivine, pyroxene (0.02-0.5 mm) and secondary feldspar bear poorly
developed and deformed, dominantly barred olivine chondrules (0.5 to
15 mm, av. 1.5 mm), metal, troilite and chromite. Dark metal-troilite
veins (50 ?m) cross the meteorite. Olivine shows rather sharp
extinction and irregular cracks.

Geochemistry: (R. Bartoschewitz, Bart, P. Appel and B. Mader, Kiel)
olivine Fa24.3-26.0 (mean Fa25.2?0.40, n=33); Ca-poor pyroxene
Fs20.8-21.7Wo1.0-1.8 (mean Fs21.3?0.24Wo1.6?0.20, n=12); Ca-rich
pyroxene Fs8.1-8.8Wo44.4-45.2 (mean Fs8.4?0.40Wo44.7?0.35, n=4);
feldspar An11-18Or 4-10, chromite Cr/(Cr+Al)=88.3, Fe/(Fe+Mg)=79.8.
Kamacite Ni=4.7-6.2, Co=1.0; taenite Ni=20-34, Co=0.3-0.7 (all in
wt.%)

Classification: L chondrite (L6, S4, W0)

Specimens: Main mass of about 700 g, E. Seemann, Braunschweig; type
specimen of 25 g, MKBraun; 500 g, Bart


Best regards and happy huntings,

MikeG

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Received on Mon 23 Sep 2013 03:39:58 PM PDT