G'day Folks,
For those who have been
wondering Dronino is now official. See the extract released today. It also
mentions that the sulfide inclusions are (~10 vol.%).
Cheers,
Jeff Kuyken
I.M.C.A. #3085
www.meteorites.com.au
www.meteoritesaustralia.com
Dronino 54o44.8΄ N;
41o25.3΄ E
Ryazan district, Russia
Found July
2000
Iron, ataxite (ungrouped)
A 40kg iron was found by Oleg Gus’kov, Moscow
resident, as he
was returning home from collecting mushrooms near the
village
of Dronino in the Ryazan district. In early 2003, it was taken
to
Vernad, and identified as meteoritic. In summer 2003,
scientific
expeditions and meteorite hunters collected more than 600
fragments
(the largest is 250 kg) totaling about 3 000 kg and occurring
at
a depth of 0.2-2 m across an area of 0.5x1.5 km. The
distribution of the
fragments suggests that the meteorite formed a
now-buried crater about 30 m
in diameter. This crater is not reflected
in the present-day topography of
the site. No historical
records exist of a meteorite fall, thus it appears
likely that the
meteorite fell earlier than the 12th century when the area
was
largely unpopulated. Classification and mineralogy (D.
Badyukov, M.
Nazarov, Vernad; J. Wasson, UCLA): the Dronino
iron is an ataxite containing
sulfide inclusions (~10 vol.%) and
consisting of kamacite (7.0±0.5 wt% Ni and
0.75 wt% Co) and
rare taenite (26.5±0.5 wt% Ni and 0.35 wt% Co) as
elongated
precipitates (1-3 µm in size) which form linear and banded
textures;
sulfide inclusions (up to a few mm in size) rounded
and
elongated along the banding; accessories are chromite and Fe
phosphate
(graftonite?); no phosphide was found and P is not
detectable in metal with
EMP; INAA data: Ni 98.1, Co 5.54
(mg/g), Cr 37, Cu 32, Ga <0.3, As 3.52, W
0.38, Ir 1.68 ppm, Au
0.284 (µg/g); the meteorite is most close to IVA irons
in Ni, Ir
and the low P but the low Au and Ga contents distinguish
the
Dronino element pattern from that of all known iron meteorite
groups.
Dronino meteorite fragments are heavily weathered and
covered with rust 1-3
cm thick. Sulfide nodules are surrounded
by Fe hydroxides, which replace
metal. Troilite of the nodules is
commonly replaced with unknown Fe,Ni
sulfides. Specimens:
type specimen 700 kg including the largest 250 kg piece
Vernad.
