Metamorphism

1
Metamorphism Metamorphic Rock
2
What is different?
3
(No Transcript)
4
Making a Metamorphic Rock

• Protolith composition (elements)
• Metamorphism
• 2. Temperature
• 3. Pressure
• 4. Fluid
• 5. Time

5
Composition

• Additional elements to the melt?

6
Protolith

• The parent rock

7
(No Transcript)
8
20 to 60 quartz 40 to 80 feldspars 0 to 20
ferromag.
20 to 60 quartz 40 to 80 feldspars 0 to 20
ferromag.
9
Metamorphosed Granite or Shale
10
Temperature

• The heat comes from
• Depth
• Magma

11
Metamorphic Grade
12
(No Transcript)
13
(No Transcript)
14
Retrograde Metamorphism
Prograde Metamorphism
15
Mineral stability
16
Pressure

• Lithostatic pressure
• Pressure Gradient
• Minerals formed at great depths vs. shallow depths

17
Stress vs. Strain
18
Differential Stress

• Directions Intensities
• Compressive stress
• Shear stress
• Alignment of crystals

19
Foliation

• Minerals crystallize out
• parallel to the direction of differential stress
• perpendicular to the compressional stress

20
Fluids

• Hot water (vapor)
• Source
• Trapped and released from pore spaces
• Condensation of a cooling magma
• A catalyst

21
Time

• Difficult to replicate P and T in lab

22
Metamorphic Textures

• Slaty Cleavage
• Schistose
• Gneissic

23
Slaty Cleavage

• Flat parallel fracture planes
• NOT parallel to the original bedding.
• Occurs often in fine-grained rocks
• Shale/slate

24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
Schistosity

• The alignment of platy minerals (e.g. micas)
• Reflective luster
• Common in coarse-grained rocks that have been
  strongly deformed.

28
(No Transcript)
29
(No Transcript)
30
Quartz Muscovite Schist
31
Metamorphic facies
32
Metamorphic environments

• Contact
• Vs.
• Regional

33
Contact metamorphism

• Controlling factors
• High temperature
• Low pressure

34
(No Transcript)
35
(No Transcript)
36
Regional Metamorphism

• Large areas (think big)
• Variable temperatures and pressures
• Foliated

37
(No Transcript)
38
Progressive Metamorphism
39
Metamorphic Rock

• Shields

40
Begin Review
41
(No Transcript)
42
Draw, describe, varying chemistry between the two
features, and discuss how the feature may have
formed (include relative time)
43
(No Transcript)
44
(No Transcript)
45
5.
1.
3.
2.
4.
46

• Draw and label
• Discuss formation

47
(No Transcript)
48
(No Transcript)
49
(No Transcript)
50
(No Transcript)
51
(No Transcript)
52
(No Transcript)
53
(No Transcript)
54
(No Transcript)
55
(No Transcript)
56
(No Transcript)