[meteorite-list] First Italian Meteorite Crater

From: M come Meteorite Meteorites <mcomemeteorite2000_at_meteoritecentral.com>
Date: Thu Apr 22 09:53:33 2004
Message-ID: <20021209204208.39282.qmail_at_web10302.mail.yahoo.com>

Hello all

Meteoritics & Planetary Science 37 (2002)
© Meteoritical Society, 2002. Printed in USA.

The Sirente crater field, Italy
Jens Ormö*, Angelo Pio Rossi and Goro Komatsu
*Correspondence author's address: International
Research School
of Planetary Sciences, Universita d'Annunzio, Viale
Pindaro 42,
65127 Pescara, Italy; e-mail address:
ormo_at_irsps.unich.it
Abstract–We propose the Sirente crater field to be the
first
discovered impact craters in Italy. They are located
in the
Sirente plain within the mountains of the Abruzzo
region, central
Italy. The craters are distributed in a field 450 m
long and 400
m wide. This field consists of about 17 smaller
craters close to
a larger main crater. The main crater is located in
the southern
end of the crater field and is 140 m long and 115 m
wide, measured
rim-to-rim. It has a well-developed, saddle-shaped rim
that rises
at a maximum 2.2 m above the surrounding plain.
Radiocarbon dating
of the target surface preserved below the rim gave a
calibrated
age of formation at about 412 A.D. (1650 ± 40
radiocarbon years
B.P.). This young age is consistent with the apparent
little
modification of the rim. The morphology of the main
crater and
its relation to a crater field strongly points to its
origin by
impact from a projectile that broke up during its
passage through
the atmosphere. Quartz is very rare in the target and
no planar
deformation features (PDFs) have been found so far.
The rim
material and the upper 4 m of the main crater infill
are
impregnated with ferric oxides, which gives a more
reddish colour
compared to the other sediments of the plain. Rusty
crusts with
high Fe and Mn content occur in the rim material, but
have not
been found in the plain's sediments. Some of these
crusts can
be separated by magnet, and have sporadic micron-sized
Ni-rich
granules. The main crater is in the size range of
craters with
explosive dispersion of the projectile and has many
features
comparable to both large experimental and meteoritic
impact
craters formed in loose sediments. We suggest that
this crater
represents a rare example of well-preserved, small
impact craters
formed in unconsolidated target materials.
(da http://www.uark.edu/~meteor/abst37-11.htm#ormo )

regards

Matteo


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Received on Mon 09 Dec 2002 03:42:08 PM PST