Term
| What is a metamorphic rock? |
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Definition
| Alteration of igneous and sedimentary rocks through heat and pressure. |
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Term
| Where do metamorphic rocks occur? |
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Definition
| Occur in locations characterized by contact metamorphism and/or regional metamorphism. |
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Term
| What Controls the Characteristics of the Final Metamorphic Product? |
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Definition
| Pressure and temperature exposure (metamorphic grade) and original chemical composition of the prolotith. |
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Term
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Definition
| The igneous/sedimentary rock that you started with (parent rock) |
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Term
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Definition
Occurs when surrounding country rock comes into contact with hot fluids
Water (hydrothermal fluids)
Magma
250-400°C temp., 2-4kb pressure (1kb = 14,700 psi)
High Temperature and LOW PRESSURE
OCCURS WHEREVER MAGMA IS GENERATED!! |
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Term
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Definition
Very large scale (continental scale)
[550-700°C temp., 5-10kb pressure (1kb = 14,700 psi)]
High temperature and HIGH PRESSURE
Results in changes in mineral composition and physical appearance.
*OCCURS AT CONVERGENT PLATE BOUNDARIES* |
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Term
| How are Metamorphic Rocks Classified? |
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Definition
| Texture and Metamorphic Grade |
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Term
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Definition
Mineral grains in rock are oriented in the same direction and align due to the forces being applied to the rock
Rock will have a “uniform shininess”
ROCK EXAMPLES: slate, schist, gneiss |
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Term
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Definition
There is no preferred orientation of mineral grains, no foliation
ROCK EXAMPLES: quartzite, marble
Grains welded together |
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Term
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Definition
Determines how much heat/pressure the rock has been exposed to.
Mineralogy changes with increasing metamorphic grade (mineral phase transitions).
Index minerals are used by geologists to determine what pressures and temperatures rock was exposed to.
(Garnet, Biotite, silliminite, quartz, ETC.)
THEY FUNCTION AS THERMOMETERS/BAROMETERS |
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Term
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Definition
lower heat and pressure
ex: slate |
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Term
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Definition
Medium heat and pressure
ex: Schist |
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Term
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Definition
High heat and pressure
ex: Gneiss |
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Term
| What changes occur with increasing metamorphic grade? |
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Definition
Grain size increases through recrystallization
Changes in mineralogy (minerals become unstable and transition to more stable mineral phases)
Textural changes (minerals become more aligned, and eventually segregate into bands containing like minerals) ex: gneissic banding |
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Term
| What types of rocks are formed at Subduction Zones? (both ocean-ocean and ocean-continental) |
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Definition
| Igneous, Metamorphic and Sedimentary |
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Term
| What types of rocks are formed at Transform Margins |
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Definition
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Term
| What types of rocks are formed at divergent margins |
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Definition
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Term
| What type of rocks are formed at an Intracontinent tectonic setting? |
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Definition
Sedimentary (major rock type)
Igneous (minor rock type - can be found if you have an igneous intrusion) |
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Term
| What types of rocks are formed at a Continental Collision? |
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Definition
Metamorphic - major rock type formed
Sedimentary and Igneous - minor rock types formed |
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