Metamorphic Rocks

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Assignments	Chernicoff, Metamorphism and Metamorphic Rocks, ch. 7.
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Lesson Outline

Read the entire chapter. Study the illustrations. Focus your attention on the vocabulary terms found in the following notes.

I. Introduction

1. Normal depths for metamorphism: below sedimentary depths, above igneous depths (Fig 7-1)
2. Definition of metamorphism
3. Metamorphic rocks underlie most of North America (Fig 7-2)

II. Conditions promoting metamorphism

1. Rocks are most stable in the environment in which they _____________.
2. ___________________ of minerals result from the migration of ions to more stable sites within the rock.
3. Heat
   1. Radioactivity
   2. Intruding magma
   3. Friction between rock bodies
4. Pressure (Fig 7-3)
   1. Compaction results from ____________ pressure
   2. Recrystallization results from ____________ pressure
   3. Foliation is derived from the Latin "foliatus," or ____________.
5. Fluids
   1. Water or magmatic gases
   2. Ions migrate in fluid

III. Common metamorphic rocks

1. Classification summarized in Figure 7-1, p. 131.
2. Template for describing metamorphic rocks.
3. Foliated rocks often derive from subjection of ____________ to greater and greater degrees of _______________ pressure.
   1. Slate
      1. Increased directed pressure and temperatures applied to shale causes ______________ of mica, foliation.
      2. Slaty cleavage
         1. Rock cleavage is not mineral cleavage: rock cleavage occurs between (atoms, minerals) and mineral cleavage occurs between (atoms, minerals)
         2. Occurs (parallel, perpendicular) to foliation planes, (parallel, perpendicular) to applied pressure.
         3. Because of _______ __________ slate is a source of blackboards, floor tiles, pool table tops, etc.
         4. Distinguish between shale and slate:
            1. Which is more compact?
            2. When struck, ______ thuds and ________ rings.
   2. Phyllite
      1. Which is shiny, a phyllite or a slate?
      2. Which is wavy, a phyllite or a slate?
   3. Schist
      1. Which may be shiny, a phyllite or a schist (or both)?
      2. Which contains clearly visible individual mica flakes, a phyllite or a schist (or both)?
   4. Gneiss
      1. Single-mineral __________ .
      2. Remnants of long-departed mountains.
      3. Form from many different __________ rocks.
      4. Series of increasing metamorphism:
         1. Mud
         2. Shale
         3. _______
         4. _______
         5. _______
         6. Gneiss
         7. Migmatite
4. Foliated rocks derived from igneous rocks
   1. __________ metamorphoses to greenschist.
   2. __________ and ___________ metamorphose to gneiss
5. Nonfoliated rocks
   1. Pure ________________ and _______________ form marble.
   2. _______________ metamorphoses to quartzite.
   3. Which effervesces under acid, marble or quartzite?
   4. Which can scratch glass, marble or quartzite?

IV. Types of Metamorphism

1. Contact Metamorphism
   1. Affected by magmatic heat and fluids, not by ____________.
   2. A metamorphic ___________ refers to the entire zone of metamorphism around a heat source (such as an igneous dike or sill).
2. _______________ regional metamorphism occurs beneath miles of rock or sediment, produces _______________ metamorphic rocks.
3. _______________ regional metamorphism occurs between converging plates, produces _______________ metamorphic rocks.
4. _______________ metamorphism including oceanic serpentinization.
5. _______________ metamorphism.
6. _______________ metamorphism from meteoritic impacts.

V. Uses of Metamorphic rocks

1. Strong and weather resistant
2. Buildings (serpentine, gneiss, marble), sculpture (marble), tombstones (quartzite)
3. Potential hazards: landslides

Focus Questions

Be prepared to answer any of these questions should they occur on a quiz or on the final exam.

1. ____________ is a metamorphic rock where flakes of mica are visible to the unaided eye:
   1. shale
   2. mica peridotite
   3. phyllite
   4. schist
   5. marble