Science - Rock Formations Ch 17 & 18
Terms
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- Igneous Rock
- Formed by the cooling and solidification of magma or lava.
- Metamorphic Rock
- Formed when another rock is changed by extreme heat or pressure.
- Sedimentary Rock
- Formed by weather or pieces of other rocks.
- Extrusive Rocks
- Formed from lava flowing onto the surface of the Earth.
- Intrusive Rocks
- Formed from slowly cooling magma deep within the Earth’s crust.
- Cementation
- Process where particles of loose sediment fill spaces and form a hard cement like substance.
- Compaction
- Process where pressure presses particles of sediment.
- Lithification
- Process where soft sediments become hard rock.
- Dikes
- Vertical cuts across existing rocks.
- Intrusions
- Magma that pushes into cracks of rocks.
- Sills
- Magma forms in horizontal cracks in existing rocks.
- Fossil
- Remains of prehistoric animals and plants preserved in rocks.
- Paleontology
- Study of fossils.
- Geologic Time Scale
- Covers the Earth’s history from its origin to the present.
- Era
- First subdivision of the geologic time scale
- Period
- a subdivision of an Era - Second on Geological Time Scale
- Epoch
- Subdivision of a Period - Last on Geologic Time Scale
- Physical charactertistics of rocks include...
- color, texture, size, shape, stacking arrangement
- Rocks can be classified by...
- a variety of textural and compositional characteristics
- 3 Groups of Rocks
- Igneous, Sedimentary, Metamorphic
- The size of crystals are determined by...
- the rate of cooling
- Sedimentary rocks can be formed by...
- evaporation, cementation, compaction, & crystallization
- When can rocks change form?
- When conditions in their environment change
- Fossils
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* Can provide information about ancient plants and animals
* Can be classified into four different groups