The compositions of the minerals : calcic plagio, Al rich Cpx, Grs- alm -
rich garnet, Fe Sp; are characteristic of a metasomatic rock : a skarn.
C.....
> Dear Colleagues,
> I have gotten a rock showing the assemblage An98 +Cpx (>10 wt% Al2O3) +
> garnet (Grs58-65Alm32-33Pry8-10) + Spinel (XMg= 0.2-0.4) + amphibole
> (Magnesiohastingsite) with minor titanite and zoisite. The rock occurs as
> a
> raft (100 X 3 sq feet) within felsic orthogneiss. The rock shows cm-dm
> thick compositional layers rich in plagioclase and mafic phases. My first
> impression is the rock could be a fragment of a troctolite dyke that was
> metamorphosed to spinel-grarnet-CPx bearing assemblage. I solicit your
> valuable opinion on this. I shall be thankful to have some references that
> publish high aluminous clinopyroxene in metamorphic rock.
> Thanking you in advance,
> Cheers,
> Pulak
>
> N.B. I append a field photograph.
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