Igneous Rocks Flashcards
How much does igneous rocks cover Earth’s surface?
5%
How much does igneous rocks make up of the Earth’s crust?
95%
How do igneous rocks form?
From cooling and solidification of lava and magma
What’s the range of temperature igneous rocks are formed?
600- 1300 degrees celcius
What are plate tectonics?
Large-scale movements and interactions between the Earth’s plates
How do you classify igneous rocks?
By texture and composition
What are the 2 types of igneous textures?
Extrusive and intrusive
What’s extrusive texture?
Lava
What’s intrusive texture?
magma
What’s the speed of cooling and crystal size of extrusive igneous rocks?
Fast and fine
What’s the speed of cooling and crystal size of intrusive igneous rocks?
Below the crust: Medium and medium
Deep under ground: Slow and large
What’s a dike?
A vertical rock between older layers of rock
What’s a sill
A tabular (parallel) sheet intrusion that has intruded between older rocks of foliation
What’s pluton?
A body of intrusive igneous rock that’s crystallized from magma slowly cooking
What’s laccolith?
A sheet intrusion that has been injected between 2 layers of sedimentary rocks
What are the 3 products extrusive volcanic activity produce?
Lava, pyroclastic debris, and gases
What’s pyroclastic debris?
Fire fragments, ash, tephra, cinders
Which eruptions form composite of strato-volcanoes?
Felsic & intermediate
What does the term composite refer to when talking about volcanoes?
Alternating types of layers
How do composite or strato-volcanoes form?
From alternating eruptions of lava and explosive ash clouds
What are the main features of a volcano?
Ash cloud, pyroclastic flow, crater, main vent, lava flow, magma chamber, secondary vent, secondary cone, and volcanic bombs
What are the typical conical volcanoes?
strato-cones or composite volcanoes
What is a caldera?
A collapsed strato-volcano
What happens when a strato-volcano collapse?
The magma chamber empties
What produces cinder cones?
Eruptions with little lava and much gas
What’s a cinder cone volcano?
A volcano built from blobs of lava ejected from a single vent
What’s a stratovolcano?
A volcano built of layers of lava, ash, and volcanic debris
What’s a shield volcano?
A volcano build from countless outpourings of fluid lava flows
What’s a batholith?
An intrusive igneous body greater than 40 sq. miles in area
What is a hotspot?
A portion of the Earth’s surface which experiences volcanism and where lava pushes up from under the mantle and creates volcanoes
What are the two well-known hotspots in the U.S.?
Hawaii and Yellowstone
