This ternary phase diagram is for the Diopside-Anorthite-Forsterite system and shows both the liquid and solid lines of descent for a chosen liquid composition (Di₃₅An₁₂Fo₅₃). During stage 1 after the liquidus is reached at 1700°, the liquid evolves in compsition down the liquidus surface (liquid 1) and pure Fo crystallises (solid 1 - fixed composition). When the liquid reaches the cotectic, diopside begins crystallising. The liquid composition evolves down the cotectic trough (liquid 2) and the solid compsosition also evolves (solid 2). Once the ternary eutectic is reached (1270°), both temperature and liquid composition become fixed (liquid 3) as anorthite joins the crystallising assemblage. The solid composition now evolves isothermally toward the bulk system composition (solid 3) until no liquid is left.
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