Geology test (Chapter 4-6)

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Igneous Rock formation
Solidification of melt- heat prevents them from completely forming- 650- 1200
Extrusive
Above earths surface heat is lost rapidly
Intrusive
Melt infuses already formed rocks
Volatiles
Interfere atomic bonds
Flux melting
Melting with volatiles
Magma groups
Felsic, intermediate, mafic, ultramafic
Aphanitic
Small minerals- extrusive
Phaneritic
Easily visible minerals- intrusive
Porphyritic
Large and small minerals
Phenocrystes
Large minerals
Ground mass
Small minerals
Pegmatitic
Very large minerals
Vitric
Glassy
Vesicular
Holes
Pyroclastic
Igneous rock made of ash
Sedimentary rocks
Made of sediment form at or near the surface
Clastic
Pre-existing Rock, most common
Chemical
chemical process
Biochemical
Made of organisms, not common
Clastic
Formation- weather: exposure to the elements, transportation: movement caused by wind, water, ice, deposition: stop moving & come to rest, lithification: long term results in stone
Lithification
Compaction: pressure reduces space between rocks
Cementation: minerals grow across the mineral grains
Plagioclase
White
Potassium
Orange
Chemical rocks
Difficult to transport usually found where formed.
Laminations
Small coverings
Graded bedding
Change in sediment size; floods & river beds
Cross bedding
Inclined beds within another bed; current, wind, water
Ripple marks
Series of ridges
Mud cracks
As mud dries it shrinks; hot or arid places
Categories: Geology