A PRESENTATION BY
CHLOE THORPE
CHARACTERISTICS
OF ROCKS
COLOR
TEXTURE
HARDNESS
WEIGHT
The Three types
of rocks
Igneous rocks are called fire rocks and are
formed either underground or above ground.
Underground, they are formed when the
melted rock, called magma, deep within the
earth becomes trapped in small pockets. As
these pockets of magma cool slowly
underground, the magma becomes igneous
rocks.
Igneous rocks are also formed when volcanoes
erupt, causing the magma to rise above the
earth's surface. When magma appears above
the earth, it is called lava. Igneous rocks are
formed as the lava cools above ground.
Rhyolite is a light-
colored volcanic rock. It has
a high silica content which
makes it very viscous. This
prevents gases from escaping
causing rhyolite eruptions to
be explosive. Rhyolite has a
silica (SiO2) content greater
than about 68 percent by
weight.
Obsidian is usually
black in color though it can also be
red or have a greenish tint. It is a
dense volcanic glass, usually
composed of rhyolite, rich in iron
and magnesium.Obsidian is formed
when the lava cools so quickly that
crystals do not have time to grow.
Obsidian fractures with very sharp
edges. It was used by Stone Age
cultures for making knives,
arrowheads, and other tools where
sharp edges are important.
Pumice is light and
porous. It forms during
explosive eruptions. Pumice
is full of holes caused by
expanding volcanic gases. It
is composed of volcanic glass
and minerals, and can form
in all types of magma:
basalt, andesite, dacite, and
rhyolite.
Sedimentary rock is formed by
mineral and other materials
sitting in water for an
extremely long time. While
the minerals and other
materials are in the water,
they will have various things
put pressure on them. After
being exposed to these
conditions for so long, it forms
into sedimentary rock.
SANDSTONE
is sand grains
cemented
together into
solid stone.
SHALE is made
from silt particles
cemented
together. It is
similar to siltstone
but with even
finer grain size,
LIMESTONE
is made primarily of
calcium carbonate
or calcite. The most
common source of
this calcite is the
shells of marine
organisms
Igneous rocks form from the
solidification of lava or magma. If it
forms intrusively, or within the
earth, the rock will have large
crystals. Granite is an example of
such a coarse-grained igneous rock.
If the rock forms extrusively, or on
the earth's surface, it will have
fine-grained crystals. Obsidian is an
example of a fine-grained igneous
rock.
SLATE is a
fined grained
metamorphic
rock.
MARBLE is a
metamorphic
rock that comes
from
metamorphosed
limestone or
dolomite.
QUARTZITE is a
coarse-grained
metamorphic rock
derived from
sandstone.
 The
upper layer of earth in which plants
grow, a black or dark brown material
typically consisting of a mixture of organic
remains
SILTY
SANDY
PEATY
CLAY
SALINE
?
YES!!
AN EASY DEFINITION IS
Rock is one object.
and
Soil is a mixture of rocks (rather small rocks:
dirt), water, minerals, bacteria, plant, animal,
fungi matter etc.
Erosion causes include - gravity, rain, flooding, wind,
drought, deforestation, farming, flowing ice
Which effects the rock and soil by
desertification, additional sedimentation, loss of habitat,
infertile soils, increased use of soil conditioners and
fertilizers, water pollution
 http://agverra.com/blog/soil-types/
 http://answers.yahoo.com/question/
 http://en.wikipedia.org/wiki/erosion
 http://en.wikipedia.org/wiki/List_of_rock_t
ypes
 http://www.zephyrus.co.uk/rocktypes.html
 http://adventuresinscience.edublogs.org/cat
egory/kids-corner/
 http://growingchillies.net/growing-chilliessoil-tips/
 http://www.soilsurvey.com.au/services.html