Question 3. The phase diagram below depicts the stability of mixtures of Payalite and Forsterite, the Fe- and Mg olivine

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Question 3 The Phase Diagram Below Depicts The Stability Of Mixtures Of Payalite And Forsterite The Fe And Mg Olivine 1 (40.14 KiB) Viewed 63 times

Question 3. The phase diagram below depicts the stability of mixtures of Payalite and Forsterite, the Fe- and Mg olivine end members, at different temperatures. O is a solid solution of the two. Describe the cooling history of a liquid with composition d. Assume complete equilibration during cooling (e. relatively slow cooling). Indude the following information: • Composition of the first crystals that form • Temperature at which the first crystals form: • Temperature at which the last trace of melt solidifies d 2000 Liquid 1800 Olss +L 1600 T(C) 1400 1 Olss 1200 ! 1000 Fo Fa 50 wt.% Forsterite • How much melt exists at 1800°C? • How much melt exlsts at 1700°C? If cooling happened quickly relative to diffusion rates in olivine crystals, what compositional pattern would the crystals have (cores rims)? Would this affect the final solidification temperature of the melt (if so, la which direction)?