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
Phenocrysts: Ol: olivine, Opx: orthopyroxene, Cpx: clinopyroxene
, Pig: plagioclase, Qtz: quartz, and Amp: amphibole.
In the A-B diagram of , 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.