Metamorphic rocks, heat and pressure, re-crystallization of atoms structures; new characteristics copyright 2013 acloutier

1. acloutier copyright 2011 1
Metamorphic Rocks
by Annie Cloutier copyright 2011

2. acloutier copyright 2011 2
• Pressure and heat increase with depth
• Pressure and heat inside the Earth cause the
changes to occur in rock
• Where does the heat come from ?
• Earth generates heat from the radioactive core
working its way up to the lithosphere
Metamorphic
Greek word origin
meta means “change”
morph means “form”

3. acloutier copyright 2011 3
Two Types of Metamorphic Groups
• Regional metamorphism > when high temperatures
and pressure affect large regions of Earth’s crust belts of
metamorphic rock happen
• Contact metamorphism > when molten rock
comes in contact with solid rock, large scale minerals
change with little deformation

4. acloutier copyright 2011 4
Regional Metamorphism

5. acloutier copyright 2011 5
Contact metamorphism

6. acloutier copyright 2011 6
Cause & Effect of Metamorphism

7. acloutier copyright 2011 7
Hydrothermal Metamorphism
when very hot water reacts with rock and alters its chemistry and
mineralogy

8. acloutier copyright 2011 8
Getting into hot water can be good
• hydrothermal fluids
invade the surrounding
rocks and change their
mineralogy, textures and
chemistry
• valuable ore deposits of
gold , copper, silver,
tungsten and lead are
formed this way

9. acloutier copyright 2011 9
Two Textures of Metamorphic Rocks
• foliated
wavy lines, bands, layers characterize
foliated rocks;
often have small crystals of mineral
grains, and long axis of parallel
alignment
Schist
Gneiss
Shale
• nonfoliated
usually form with blocky crystal
shapes; sometimes record faint
color ripple marks
Quartzite
Marble
Calcite

10. acloutier copyright 2011 10
Gneiss >
• Schist >
< Slate >

11. acloutier copyright 2011 11
It’s Morphing time..
• Metamorphic Rock
• Gneiss <
• Marble <
• Slate <
• Mica schist <
• Parent Rock
• Granite
• Limestone
• Shale
• Mica pegmatite
Its Morphin’ time !

12. acloutier copyright 2011 12
The Rock Cycle

13. acloutier copyright 2011 13
The end is not…it’s all a cycle

14. acloutier copyright 2011 14
• …but this is the end of the power point