We have determined in situ concentrations of 28 trace elements (REE, Ba, Rb, Sr, Th, U, Nb, Ta, Pb, Zr, Hf, Y, Sc, V, Co and Cr) in olivine, plagioclase, orthopyroxene,
clinopyroxene, amphibole and phlogopite on two polished thick sections (130 [micro]m) by laser ablation ICP-MS at the Natural History Museum of London, using a New Wave UP193FX gas laser source operating at 193 nm coupled to an Agilent 7500CS ICP-MS.
The pillow lavas have microvesicles that are filled with chlorite; carbonate and opaque minerals that located in a groundmass of plagioclase and
clinopyroxene microlites.
Phenocrysts: Ol: olivine, Opx: orthopyroxene, Cpx:
clinopyroxene, Pig: plagioclase, Qtz: quartz, and Amp: amphibole.
In the A-B diagram of [31], the samples show a negative slope in IV sectors of metaaluminous area that is such a trend characteristic of cafemic (CAFEM) rocks due to presence of hornblende, ortho- and
clinopyroxene, biotite, epidote, and titanite in origin (Figure 9(a)).
5a), which could be explained by -20%
clinopyroxene fractionation from other West Valley magmas but at pressures much higher than would be expected for an incipient rift in thin crust (Cousens et al.
Mafic minerals (biotite and hastingsitic hornblende with rare
clinopyroxene inclusions) account for up to 10 vol% of the rock.
Andesine to oligoclase ([An.sub.27-30]) predominate over sodic sanidine and scarce
clinopyroxene and titanomagnetite in the matrix of fresh trachyandesite facies.
The flow is a coarse-grained, ophitic basalt containing heavily altered plagioclase and relatively unaltered
clinopyroxene. Cornwall identified these amygduole string patterns as pegmatite layers.
In contrast, the moon's surface appears to have roughly equal mixtures of these two minerals and one other,
clinopyroxene.
Eclogites mainly consist of garnet, omphacitic
clinopyroxene and symplectite with minor rutile and epidote group minerals (including zoisite, clinozoisite and epidote).
Blundy, "A predictive model for rare earth element partitioning between
clinopyroxene and anhydrous silicate melt," Contributions to Mineralogy and Petrology, vol.