[meteorite-list] Vaca Muerta euc- what is it?

[bernd.pauli at paulinet.de]

AL kindly wrote:

"I believe there is an absence of olivine in mesosiderites."

Objection, Your Honor!

Norton O.R. (2002) The Cambridge Encyclopedia of Meteorites, p. 157:

"Accessory amounts of olivine are also present in mesosiderites"
"...the mineralogy of the silicate portion...is ...orthopyroxene and
plagioclase with minor amounts of olivine."

Norton O.R. (2008) Field Guide to Meteors and Meteorites, p.173:

a) Figure 8.10: "Estherville...Silicates include olivine, pyroxene, and plagioclase..."
b) Figure 8.11: "Vaca Muerta...Like Estherville, it contains eucritic pebbles and
    many silicate inclusions..."

T.H. Burbine et al. (1996) Mantle material in the main belt:
Battered to bits (Meteoritics 31-5, 1996, 607-620, p. 609):

"Mesosiderites are stony-iron meteorites containing Ni-rich Fe metal and mafic
 silicates (Floran, 1978). The amount of metal has been found to vary from 17
 to  80 wt% but is usually between 40 to 60% (Mason and Jarosewich, 1973). The
 silicates are mainly orthopyroxene and plagioclase with lesser amounts of other
 silicates such as pigeonite and olivine (Floran, 1978)."

By the way, a few years ago, Martinez Rodrigo offered thin Vaca Muerta slices
with predominantly eucritic components and / or olivine crystals. Some of the
olivine-rich slices were cut so thinly that they were even translucent when held
up against the light.

Best wishes,

Bernd