Engineering geology: Formation and classification of geomaterials II Flashcards
What is metamorphism?
Metamorphism is the solid-state transformation of pre-existing rock into texturally or mineralogically distinct new rock as a result of high temperature, high pressure, or both.
What is specific to each metamorphic rock?
The layers
What happens when sandstone is metamorphosed?
- Becomes more crystalline - massive and structureless
- Grains transform and become inter-grown quartz crystals (no void spaces)
What does massive mean?
Isotropic, homogeneous rock with a strength that does not vary appreciably from point to point.
What is a feature of metamorphic rocks?
Minerals whose composition and lattice are in equilibrium with existing conditions
Why can metamorphism happen at high degrees?
Due to how much energy inputted and pressure, and heat
What are the 3 types of metamorphism?
- Dynamic or dislocation
- Thermal or contact
- Regional (temperature + stress)
What does non-foliated mean?
Non-foliated metamorphic rocks do not have a platy or sheet-like structure
Why can slate not transform igneous rocks?
Not enough energy
What is marble?
Marble is a metamorphic rock composed of recrystallized carbonate minerals. Metamorphosed limestone/chalk
What coarseness of foliation can you have?
- Slaty Cleavage
- Schistosity
- Banding
What are garnets?
Form other new minerals inside the rock itself
What shape of rock do we generally test?
Cylinders
Why does weathering weaken rocks?
As you weather a rock you are degrading the quality of the material - crystals break
What types of rock strength tests are there?
- Brazilian tensile test
- Point load test
- Unconfined Compression test
