Download Section 10-4

Section 10-4
• Where does most igneous activity take place?
• Define the following terms for igneous rock
features:
– Batholith
– Dike
– Sill
– Laccolith
– Volcanic neck
– Caldera
• Batholith – the largest intrusive igneous rock
body
• forms when magma cools and solidifies
underground and stops rising to the surface
• Dike – forms when magma is squeezed
into a vertical crack that cuts across rock
layers and solidifies underground
• Sill – forms when magma is squeezed
into a horizontal crack between rock
layers and solidifies underground
• Laccolith – a dome of rock that forms when a
sill pushes the rock layers upward
• Volcanic neck – the solid igneous core of a
vent that remains after the outer layers of lava
and tephra have been eroded away from an
extinct volcano
• Caldera – the large opening formed at the top
of a volcano when a crater collapses into the
vent following an eruption
Mountains p. 123-125
• Describe the 4 main types of
mountains.
• Folded mountains – are created when rock
layers are squeezed from opposite sides,
causing them to buckle and fold
• Upwarped mountains – are formed when
Earth’s crust is pushed up and eroded, forming
sharp peaks and ridges
• Fault-block mountains – jagged mountains
formed from huge, tilted blocks of rock that
are separated from surrounding rock by faults
• Volcanic mountains – created when magma
within Earth escapes to the surface, building
cones of lava and ash