18.3 – Intrusive Activity

http://3dparks.wr.usgs.gov/2005/lakemead/images/volcanic.gif

Plutons

• Intrusive igneous rock body, including __________, ________,sills & dikes

• Formed through ___________-building processes and ___________-oceanic collisions

• Can be __________ at Earth’s surface to uplift and erosion

http://www.geo.hunter.cuny.edu/bight/images/pluton.jpg

Batholiths & Stocks

• The _______ plutons are called Batholiths.• Batholiths are _________-grained,

irregularly shaped, igneous rock mass that covers at least ________ km2

• Stocks are ___________ shaped plutons but ___________ in size.

• Both generally form 5-______ km below Earth’s surface and are _________ in the interior of major _____________ chains

Laccoliths

• Relatively _____________• ____________-shaped pluton that forms

when magma ___________ into parallel rock layers ________ to Earth’s surface

• Laccoliths have

________ bottoms

and ___________

tops.

http://www.indiana.edu/~geol105/images/gaia_chapter_5/dike&sill.jpg

Sills

• Pluton that forms when magma ________ parallel rock ______________

http://www.austmus.gov.au/geoscience/images/earth_diagrams/volcano_structure.gif

Dikes

• Pluton that cuts __________ preexisting rocks and often forms when magma ____________ cracks in surrounding rock ____________

http://www.waipahums.k12.hi.us/eportfolio05-06/wisportfolio05-06/team8d_portfolios/y_kenneth_e_portfolio/volcano_files/image002.png

Plutons & Tectonics

• ____________ plutons form as the result of _____________-building processes.

• Plutons are thought to form as a result of _________________-continental and ___________-continental convergence.

Reinforcement

• T/F• Batholiths are common in the interiors of

mountain chains.• Laccoliths have curved bottoms and flat

tops.• Sills form when magma is forced between

rock layers.• Most igneous activity occurs deep within

earth.