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38 Cards in this Set
- Front
- Back
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Metamorphism |
The transformation of one rock into another by temperatures and/or pressures unlike those in which the original rock formed |
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temperatures greater than |
300 degrees c |
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metamorphic rocks can be produced from: |
igneous rocks sedimentary rocks other metamorphic rocks
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Metamorphism progresses how? |
continuum from low-grade to high-grade |
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Types of metamorphism |
contact or thermal hydrothermal regional |
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agents of metamorphism |
heat pressure chemically active fluids |
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pressure |
isotropic - confining pressure applies forces equally in all directions, increases with depth
anisotrophic - unequal pressure in different directions. induces differential stress |
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Metamorphic textures |
foliated, differential stresses
non-foliated, confining pressure |
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foliation |
any planar or banded arrangement of mineral grains or structural features within a rock
parallel alignment of flattened mineral grains and pebbles
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foliated textures |
slaty parting schistocity or schistos gniessic banding augen texture
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non-foliated textures |
fused granular poryphyroblastic eclogitic |
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slaty parting |
Closely spaced planar surfaces along which rocks will easily split
Individual grains are generally microscopic |
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schistosity |
– Platy minerals are |
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gneissic banding |
During higher grades of |
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Augen Structures |
During higher grades of |
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porphyroblastic texture |
Large grains, called porphyroblasts, surrounded by a fine grained matrix of other minerals high fluid content in parent material |
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eclogitic texture |
extreme high temp and confining pressure
low fluid content in parent material garnets in a (NA-rich_ green pyroxene matrix |
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fused granular |
metamorphism of chemical sedimentary rocks and pure sandstones |
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Slate |
foliated rock very fine-grained excellent rock cleavage low grade metamorphism of shale |
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phyllite |
foliated rock platy minerals not large enough to be identified with the unaided eye glossy sheen and wavy surfaces contains fine rystals of muscovite and or chlorite micas
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schist |
foliated rock medium to coarse grained platy minerals predominate
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gneiss |
foliated rock banded appearancs; warped or bent bands high grade metamorphism
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quartzite |
nonfoliated rock formed from a parent rock of quartz rich sandstone quartz are fused together |
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argylite |
nonfoliated formed from a predominantly clay parent rock such as shale tightly fused finegrained metamorphic rock
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marble |
nonfoliated coarse crystalline parent rock was limestone or dolostone composed essentially of calcite or dolomite crystals variety of colors
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anthracite coal |
nonfoliated formed from plant matter highest grade of coal |
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shock metamorphism |
occurs when high speed projectiles called bolides strike earth's surface
impactites |
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metamorphism occurs along |
convergent plate boundaries |
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knowledge of earth's interior comes from |
study of seismic waves aka earthquake waves |
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compressional waves |
(p waves) about to propagate through liquids as well as solids |
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shear waves |
(s waves) cannot travel through liquids
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when seismic waves pass from one material to another |
part of the energy is reflected by the interface part of the energy passes into the next layer and the path of the wave is refracted or bent |
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crust |
the comparatively thin outer skin that ranges from 3km at the ocean ridge up to 70 km in some mountain belts |
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continental crust |
exceeds 70km under some mountainous regions average rock density about 2.7 g
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oceanic crust |
3 - 15 km thick density 3g
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mantel |
solid rocky interior layer 82% of earths volume |
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athenosphere |
upper mantle density 3.3-3.7 allows plate movement
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mesosphere |
lower mantle 4.2-6
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