Igneous Rocks Flashcards
a naturally-occurring aggregate of one or more minerals; may or may not contain natural glass and organic matter
Rock
classified by mineral and chemical composition; the texture of the constituent particles; and also by the processes that formed them
Rocks
Ignis means?
fire
form when magma (molten rock) cools and crystallizes, either at volcanoes on the surface of the Earth or while the melted rock is still inside the crust
Igneous Rocks
molten rock generated by partial melting of rocks in Earth’s upper mantle and in the lower crust in smaller amounts
Magma
collects in many separate magma chambers within the Earth’s crust; different compositions in different places
Magma
magma will have a longer time to crystallize mineral while in the ____________
subsurface
these rocks form when magma cools and solidifies underground
Intrusive Rocks
these rocks form when the molten material (lava) reaches the Earth’s surface
Extrusive Rocks
Liquids in Magma
Silicate (sometimes carbonate or
sulfide)
Ions of K, Na, Fe, Ca, Mg, Al
Solids in Magma
Minerals
Rock fragments
Dissolved Gas in Magma
H₂O, CO₂, SO₂
Temperature of Magma
600-1200°C
Property to resist flow
Viscosity
higher temperature, (lower/higher) viscosity
lower
higher SiO₂, (lower/higher) viscosity
higher
higher dissolved H₂O, (lower/higher) viscosity
lower
Felsic, Silicic or acidic (>63% SiO₂)
Intermediate (52-63% SiO₂)
Continental Crust
Mafic or basic (45-52% SiO₂)
Oceanic Crust
Ultramafic or ultrabasic (<45% SiO₂)
Upper Mantle
Types of Magma
Felsic
Intermediate
Mafic
Ultramafic
Types of Magma is classified according to
Temperature
Silica Content
Viscosity
Type of Igneous Rocks:
molten rock solidified at the surface
ex. Basalt, Andesite, Rhyolite
Extrusive (volcanic)
Type of Igneous Rocks:
igneous rocks formed at depth
ex. Gabbro, Diorite, Granite
Intrusive (plutonic)
Classification of Igneous Rocks:
very fine-grained (<2mm in diameter) as a result of rapid cooling at the surface
- minerals too small to be seen by the naked eye
Aphanitic
Classification of Igneous Rocks:
coarse-grained (>5 mm) mineral sizes due to magma cooling at depth.
Phaneritic
Classification of Igneous Rocks:
very large crystals (phenocrysts) embedded in smaller crystals (groundmass)
Porphyritic
Classification of Igneous Rocks:
contain tiny holes called vesicles formed due to gas bubbles in the lava or magma
Vesicular
Classification of Igneous Rocks:
molten rock quenched quickly as it was ejected into the atmosphere
Glassy
Classification of Igneous Rocks:
formed when volcanic materials are extruded violently; made of rock fragments rather than crystals
Pyroclastic
