[meteorite-list] Cohenite Question

[bernd.pauli at paulinet.de]

Cohenite = [(Fe,Ni,Co)3C]


Hello Martin and List,
 
> I never saw a hexaedrite, a IIG, a IIAB, a IIE,
> a IIIAB with cohenite and they have <7% Ni.

Angra dos Reis (iron):

Cohenite was noted in one place as a cluster of
10-50 µ frayed (= to cause strain on sth.) units.

Arispe:

Cohenite has provided carbon for
local martensite-bainite formation.

A most unique characteristic of Arispe
is the distribution of the cohenite nests.

Cohenite is also present as a 100-200 µ thick
envelope around the larger schreibersite bodies.

Bendego:

Cohenite is present in significant amounts.

Chihuahua City:

.. composed of polycrystalline Fe/Ni with cohenite.

Etosha:

.. cohenite inclusions with unusual morphologies

Lake Murray:

.. cohenite is decomposed to graphite and granular kamacite

Santa Rosa:

Polycrystalline iron with cohenite and graphite.


References:

BUCHWALD V.F. (1975) Handbook of Iron Meteorites.

BRETT R. (1967) Cohenite: Its occurrence and a
proposed origin (GCA 31, 143-159).


Best wishes,

Bernd