Download Volcano

What is this Volcano?
Cinder Volcano
Composite Volcano
Shield Volcano
Volcanoes
Explosive liquid lava
Ash-cinder from vents
Will form a shield
volcano
High and steep
Subduction
Highly explosive
Thick lava
Large and flat
Subduction zones
Low explosive
Liquid lava
Sunset Crater in AZ
Paricutin in Mexico
Mt. St. Helens
Mt. Hood, OR
Hawaiian Islands
Overview of the Rock Cycle
 The rock cycle describes Earth’s natural process of
recycling rocks and sediments.
 All the rocks on Earth fall into the three distinct
categories of sedimentary, igneous, or metamorphic
rocks.
 The names of these rock types refer to the way the
rocks were formed
Igneous Rocks
 Igneous rocks are formed from
magma, the molten form of Earth’s
mantle layer.
 These rocks can form above ground
when lava comes out of a volcano, or
they may form under the Earth’s
surface when magma cools.
 When igneous rocks are broken
down chemically and physically the
pieces of this rock may become solid
rock, creating sedimentary rock. Or,
if these rocks undergo heat and
pressure they may turn into
metamorphic rock.
 Granite is a common igneous rock
that is formed under the Earth’s
surface.
 About 75% of the Earth’s crust is
granite.
Sedimentary Rocks
 Sedimentary rocks form from
weathered pieces of other rocks
(metamorphic, igneous, or
other sedimentary rocks) or
from weathered shells of sea
creatures.
 Also, sedimentary rocks can be
precipitated directly out of
water as is the case with
limestone.
 Coal is also an example of a
sedimentary rock.
 Coal forms when dead organic
matter is squeezed together
before the material can be
decayed. Whatever the case,
these rocks must be squeezed
and cemented together.
Metamorphic Rocks
 Metamorphic rocks form under intense heat
and pressure.
 These rocks may start out as igneous,
sedimentary or another type of metamorphic
rock, but due to heat and pressure the
characteristics change, generating a
metamorphic rock.
 It is important to know that rocks continue to
change form. What was once a sedimentary rock
may become a metamorphic rock when
subjected to extreme heat and pressure.
 With sufficient time and weathering, that
metamorphic rock can become a sedimentary
rock once again. Evidence of deformation and
stress is often associated with metamorphic
rocks due to the fact that they were subject to
extreme heat and pressure.
 One very common metamorphic rock, is
marble. Marble is formed when heat and
pressure are applied to limestone for many
thousands of years.