Dhofar 019
Oman
Found 2000 January 24
Martian basalt (shergottite)
A brownish gray stone
weighing 1056 g was found in the desert. Mineralogy and
classification (M. Nazarov and M. Ivanova, Vernad; L. A. Taylor,
UTenn): fusion crust absent; meteorite is a doleritic rock
consisting of subhedral grains (0.2–0.5 mm) of pigeonite (Wo9–1 5
En40–70, Fe/Mn = 20–40 at), augite (Wo30–40 En40–55), olivine
(Fo25–60, Fe/Mn = 50–60 at), and feldspar (An36–68) converted to
maskelynite; olivine has higher Fe/Mg than that of coexisting
pyroxenes, as it is in nakhlites; mineral modes (approximate volume
percent) are pyroxene = 65, maskelynite = 25, and olivine = 10, with
accessory silica, K-rich feldspar, whitlockite, chlorapatite,
chromite, ilmenite, titanomagnetite, magnetite, and pyrrhotite;
secondary phases are calcite, gypsum, smectite, celestite, and Fe
hydroxides; shock features include fracturing and mosaicism,
maskelynite, and rare impact-melt pockets; extensive terrestrial
weathering present mainly as carbonate veins crosscutting the
meteorite, however, there are smectite–calcite–gypsum "orangettes"
replacing maskelynite, which are similar to those in Allan Hills
84001 and could be of martian origin; bulk chemistry close to
Shergotty, with light rare earth elements strongly depleted.
Specimens: type specimens, 113, 4, and 2 g, and two thin sections,
Vernad; main mass with anonymous finder.
I bought the last two slices
from the Russian finders, one left intact, the other broken up.
Below is a link to the NASA
Martian Meteorites webpage and a paper on the Dhofar 019
meteorite.
http://www-curator.jsc.nasa.gov/antmet/mmc/XVII-%20Dhofar.pdf
