Thin sections of dyke contacts show microporphyritic crystals of plagioclase, augite, and orthopyroxene
scattered in a dark glassy matrix (Fig.
2006, Investigating the depth of komatiite melting using experimentally determined olivine and orthopyroxene
melt reaction coefficients: American Geophysical Union, Fall Meeting, 2006, abstract V24B-05.
Harzburgites have granular, amorph granular and Milonite textures and amorph Olivine 70-80%), amorph Orthopyroxene
(15-25%), Clinopiroxine (5%) and Chrome Spinel (less than 2%) and Menitite crystals are seen in their mineralogy composition.
Modal mineralogies are defined by plagioclase (~30-95 vol%), orthopyroxene
(<1-45 vol%) and clinopyroxene (<1-25 vol%), with accessory (<10 vol%) abundances of Feo-Ti oxide, olivine, hornblende, biotite, apatite, and secondary minerals (e.
According to the IUGS classification criteria (Le Maitre, 1989) this intrusive body can be described as a leucocratic gabbro/dolerite with massive structure, with equigranular and subophitic texture, medium to coarse grain sized, composed by plagioclase (An55-45), altered olivine, orthopyroxene
, clinopyroxene (augite), opaque minerals and apatite.
Generally, early crystallizing minerals such as olivine, clinopyroxene, plagioclase and orthopyroxene
contain very low REE abundances (Table 2).
The most abundant minerals found were olivine, clinopyroxene, and orthopyroxene
From sample 3005150, garnet, plagioclase, and orthopyroxene
have been used for Sm-Nd studies (Table 2, Fig.
They consist of plagioclase laths, orthopyroxene
, clinopyroxene, amphibole, and biotite in a groundmass of plagioclase and K-feldspar (Figs.
The ultramafic rocks are composed of variably serpentinized olivine, clinopyroxene, orthopyroxene
, and tremolite.
Formulas for olivine, augite, orthopyroxene
(Opx), plagioclase (Plag) and nepheline calculated on the basis of 4, 6, 6, 32 and 32 oxygen, respectively.
However, ALH84001 contains relatively high-density material, including the mineral orthopyroxene