Download Lab 6: Metamorphic Rock

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