[meteorite-list] Ankerite

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 10:04:48 2004
Message-ID: <3CDFDF9C.D10FD66D_at_lehrer1.rz.uni-karlsruhe.de>

Paul Dudley wrote:

> Ankeritic carbonate is essentially dolomite that has iron and
> manganese substituting for some of the magnesium and/or calcium

Treiman Allan wrote:

> Ankerite is the mineral name for the iron-bearing
> equivalent of dolomite. Dolomite is CaMg(CO3)2,
> and ankerite is CaFe(CO3)2.

> The ankerite is most likely Martian in origin, because
> it requires low-oxygen conditions (reducing) to form,
> unlike Earth's atmosphere. So, like the carbonate minerals
> in ALH84001 and in Nakhla, it suggests that liquid water
> containing carbonate circulated underground on Mars.


Hello Paul, Allan and List,

RUBIN A.E. (1997) Mineralogy of meteorite groups
(Meteoritics 32-2, 1997, 231-247) - p. 233:

ankerite = Ca(Fe+2, Mg, Mn) (CO3)2

and on p. 241:

ALH 84001 is a coarse-grained, cataclastic orthopyroxenite
consisting mainly of orthopyroxene grains ... minor to
accessory phases include maskelynite, ... , Mg-Fe-Ca (Mn)
carbonate ... + Reference Z3, p. 247:

ZOLENSKY M.E. et al. (1988) Aqueous alteration (in Meteorites and
the Early Solar System, eds. J.F. Kerridge et al., pp. 114-143, UoA
Press).

Best wishes,

Bernd
Received on Mon 13 May 2002 11:45:32 AM PDT