Igneous Rocks Flashcards
What is a Phanerite?
Coarse grained igneous rock
What is a Phanerite?
Coarse grained igneous rock
What is Pegmatite?
Igneous Rock with unusually large grains
What is Aphanite?
Fine grained igneous rock
What 3 descriptors describe the grains of igneous rock?
Phanerite, Pegmatite, Aphanite
How is a glassy igneous rock formed?
When magma cools very quickly (e.g obsidian)
What are the 6 most common minerals in igneous rocks?
Quartz, feldspar, Mica, Amphibole, Pyroxene, Olivine
What is a pluton?
An intrusive igneous body
What is the name given to an intrusive igneous body?
A pluton
What are the 5 types of minor pluton?
Dyke, Sill, Laccolith, Volcanic pipe, Kimberlite pipe
What is the largest pluton type (major pluton)?
A batholith
What’s the difference between a dyke and a sill?
Both tabular and sheet like but a dyke cuts across a body of rock, and a sill runs parallel to the layering/fabric of the rock it intrudes
Describe a laccolith.
An intrusion parallel to the layering of existing rocks which forces the ones above it to bend up like a dome
What is a volcanic pipe?
A pipe shaped conduit, usually vertical that once fed magma to a volcanic event.
What is a kimberlite pipe?
A cylindrical intrusion
