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Rocks and Minerals Lab 6 NAME____________________ ROCKS AND MINERALS Lab 6: Metamorphic Rock-forming Minerals DUE: Part I is due by the end of lab; part II is due at the beginning of lab next week OBJECTIVES to familiarize yourself with physical characteristics of common metamorphic rock-forming minerals. to review the occurrences of these minerals in metamorphic rocks. to develop a reference for use during the metamorphic part of this class. ASSIGNMENT PART I: Complete the table below. For #17, there are 2 minerals that need to be identified. When you are done with this part of the assignment, check your answers with one of the instructors. Then proceed to Part II. Facies is a scheme by which we classify metamorphic minerals based upon their mineralogy. Protolith is the original rock that underwent metamorphism to generate the sample of interest. See pg. 345 of your text, which describes 4 protoliths: mafic, ultramafic, mudrock, calcareous and the characteristic minerals found in each facies. Mineral ID hints (refer to your text for complete descriptions) Garnet Equant xtls, no cleavage Muscovite Andalusite Square prisms, incl. may form cross pattern Biotite Kyanite Blue or green bladed xtls Chlorite Sillimanite Colorless, elongate xtls, comm. assoc. w/ bt Talc Staurolite Yel. to brn. xtls, cross-shaped twinning Serpentine Epidote Yellow-green to dk green xtls K-feldspar Actinolite Green elongate xtls, 60-120 cleavage Calcite Tremolite White elongate xtls, 60-120 cleavage Dolomite 1 Colorless, 1 perfect cleavage, elastic flakes Black, 1 perfect cleavage, elastic flakes Green, 1 perfect cleavage, inelastic flakes H=1, soapy feel Fibrous or fine-grained masses, H=2.5-3.5 90° cleavage, commonly white or pink 3 cleavages at 75°, H=3, rxn with HCl 3 cleavages at 75°, H=3, no rxn w/ HCl unless powdered Rocks and Minerals Lab 6 TABLE FOR PART I Sample # Physical Characteristics Mineral Name Formula 1 2 3 4 2 Common protolith Common facies Rocks and Minerals Lab 6 Sample # Physical Characteristics Mineral Name Formula 5 (green mineral) 6 7 8 3 Common protolith Common facies Rocks and Minerals Lab 6 Sample # Physical Characteristics Mineral Name Formula 9 10 11 12 4 Common protolith Common facies Rocks and Minerals Lab 6 Sample # Physical Characteristics Mineral Name Formula 13 14 (lg. brown xtls.) Bonus: ID another mineral from this lab. 15 16 5 Common protolith Common facies Rocks and Minerals Lab 6 PART II: Answer the following questions: 1. Name the 3 aluminosilicate polymorphs that are important metamorphic minerals, and ACCURATELY sketch the P-T phase diagram for these. 6 Rocks and Minerals Lab 6 2. Study the P-T diagram on page 344 and the table (Table 17-1) on page 345 of Blatt, Tracy and Owens. For the following facies, FROM THE MINERALS IN THIS LAB, list three important (diagnostic) minerals that may be present in each facies. In parentheses next to each mineral, give the corresponding sample number from part I. Zeolite facies ______________________________________________________________________________________________ Greenschist facies __________________________________________________________________________________________ Amphibolite facies __________________________________________________________________________________________ Granulite facies ____________________________________________________________________________________________ Blueschist facies ___________________________________________________________________________________________ Eclogite facies _____________________________________________________________________________________________ 3. Summarize the characteristics that will allow you to distinguish the following mineral pairs: actinolite – chlorite epidote – chlorite 7 Rocks and Minerals Lab 6 sillimanite – quartz andalusite – staurolite talc – quartz calcite – dolomite garnet - staurolite 8