Magma and IGNEOUS Rocks Flashcards
extremely hot liquid and semi-liquid rock located under Earth’s surface
magma
3 classifications of magma
mafic
intermediate
felsic
Have high silica content (>63%)
High silica content made it very viscous which causes explosive volcanic eruptions
Can erupt at low temperatures (800°𝐶)
felsic magma
Have low silica content (45-52%) and high ferromagnesian content
Low viscosity
Can erupt at high temperatures (1100°𝐶)
mafic magma
Have silica content (52-63%) and relatively high ferromagnesian content
Can erupt at temperatures (850 to 1100°𝐶)
intermediate magma
Have low silica content (<45%) and very high ferromagnesian content
Can erupt at high temperatures (1600°𝐶),
Highly mobile liquid in eruption.
Rare and very old
ultramafic magma
Formed by cooling and crystallization of magma
igneous rocks
forms within crust/below ground surface
takes centuries – millions of years to form
Also called Plutonic rocks
Can be found in great mountain ranges
intrusive igneous rocks
forms above ground surface;
takes seconds to years to form
Also called Volcanic rocks
Can be found near volcanoes and ocean floor
extrusive igneous rocks
shows how minerals are formed as magma cools and becomes igneous rocks
Bowen’s Reaction Series
Discontinuous Branch
Olivine => Pyroxene => Amphibole => Biotite
you transform some/all of your previously formed minerals to new minerals
discontinuous branch
Continuous Branch
Plagioclase Feldspar goes from calcium-rich to sodium- rich form as the temperature drops and as long as sodium is available in magma
Mafic:
Intermediate:
Felsic:
Basaltic
Andesitic
Rhyolitic
Plutons that are large and irregularly shaped
stocks or batholiths
a pluton that is sheet-like and is parallel to the existing layering of the underground materials
sill
similar to sill but cuts across the existing layers of underground materials
dyke
a sill that has expanded and pushed the rock above it
laccolith
a “cylindrical” conduit (may have any cross- sectional shape) that serves to allow movement of magma
from one point to another
pipe
used as aggregates in concrete, rock fill for dams, railroad ballast, and highway base course
extrusive rocks
