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Unformatted text preview: GLG 321 2008 Problem Set #3 1 Problem Set 3 Name: ____________________ Polymorphism, Chemical Variation and Graphical Representations This problem set is due Thursday February 7. Please read the questions carefully and answer them completely. If the question asks “why?” or says to “explain” then you must write out your explanation. 1. Enstatite MgSiO 3 is a common mafic mineral in Earth’s upper mantle. In the deep Earth, MgSiO 3 can also occur in a garnet structure (majorite Mg 3 MgSiSi 3 O 12 ) and as a high-pressure clinoenstatite. a) Are orthopyrxene, majorite and high-P clinoenstatite isomorphs or polymorphs? b) We find majorite in small meted regions of shocked meteorites. In most cases, the majorite formed from the transformation of enstatite at high pressure and temperature. What type phase transformation change enstatite to majorite garnet? Explain your answer. ( Hint: the structure of pyroxene is very different form that of a garnet.) 2. Potassium feldspars (KSi 3 AlO...
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This note was uploaded on 04/03/2008 for the course GEO glg 321 taught by Professor Tom during the Spring '08 term at ASU.
- Spring '08