Transcript Processes of rock and fossil formation

Comparisons of rocks and minerals and how they are related
PROCESSES OF ROCK AND FOSSIL
FORMATION
MINERAL DEFINITION
A mineral is a substance found in nature. They
are solid, non-living substances.
 Minerals are made of atoms
 Earth has more than 3,500 different kinds of
minerals.
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MINERAL PROPERTIES
Crystal shape – A mineral’s atoms can make
shapes called crystals. The crystal gets its
shape from the way the atoms inside are
arranged. Crystals have smooth, flat surfaces
and sharp edges.
 Cubic
orthorhombic
rhomboid
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MORE MINERAL PROPERTIES
Hardness
Hardness test – Mohs scale from 1 – 10
Talc
#1 --------- Diamond
#10
Streak – The colored line a mineral makes on a
plate.
MORE MINERAL PROPERTIES
Some minerals break apart in a special way.
 Cleavage
Fracture
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Color
Luster
ROCK DEFINITION
When minerals mix together, they become
rocks.
 Magma is made from many minerals.
 As magma cools, the minerals harden together
and become rocks.

IGNEOUS ROCKS
Igneous rocks are rock made from cooled
magma.
 Obsidian
Granite
Basalt
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METAMORPHIC ROCKS
Metamorphic rocks are changed by being
heated and squeezed.
 Metamorphic rocks are usually very dense.
 Gneiss
Schist
Marble
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SEDIMENTARY ROCKS
Sedimentary rocks are made of pieces of
sediment that have been glued together.
 The glue for the rocks is made when water
dissolves some minerals which later harden.
 Breccia
Conglomerate Sandstone

ROCKS UNDERGO CHANGES OVER TIME
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The rock cycle is continuous and moving in all
possible directions.
ENERGY IS RESPONSIBLE FOR CHANGES TO
ROCKS OVER TIME.
It takes mechanical energy to move the
sediments to form sedimentary rocks.
 Magma has a tremendous amount of heat to
melt minerals together.
 It requires tremendous heat and pressure to
form metamorphic rocks.

EROSION
Erosion changes the surface of the Earth by
wearing away the materials.
 mudslide
water erosion Dust storm
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WEATHERING
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Weathering changes Earth materials.

Chemical
Mechanical
SOIL FORMATION

Soil forms when rock has been weathered and
eroded.
FOSSILS
Fossils are the remains or traces of ancient life.
 They are at least 10,000 years old.
 They can be mineralized samples such as
petrified wood.
 They can be materials from the organism like
bones and fur.
 They can also be traces of the organism like
footprints or nests.
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FOSSIL FORMATION
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Fossils are most commonly formed when:
1. An animal dies and its skeleton settles to the seafloor where
it is buried by sediment.
2. The sediment thickens and begins to turn to stone.
3. The skeleton dissolves and a mold is formed.
4. Minerals crystallize inside the mold and a cast is formed.
5. The fossil is exposed on Earth’s surface due to erosion.
DEPOSITION
Deposition happens when the energy causing
the transportation of sediments is unable to
move them further.
 Therefore, they are deposited in an area.
 Sediments are deposited in layers.
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RELATIVE AGE
Rocks are dated by relative age.
 The older rocks are said to be at the bottom,
while the younger rocks are normally on the
top.
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FOLDING
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These rocks have been folded
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In this case the youngest ones may not always
be on top.
FAULTING
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These rocks have been faulted
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Again some of the rocks have shifted, so
relative age is harder to determine.
FOSSILS AS EVIDENCE

Fossils show evidence of the changing surface of
the Earth.
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This fish fossil found in a mountain side is
evidence that there was once a water habitat in
this area.
FOSSIL LAYERS
Recently deposited fossil layers are more likely
to contain fossils resembling existing species
than the older rock layers.
 The fossils in unit O will
be closer to the existing
species than those in the
lower units.
M will contain the oldest
species.
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EARTH’S ENERGY CAN BE TRANSFERRED

Energy from Earth’s interior causes changes to
Earth’s surface.
Earthquakes
Volcanoes
EARTH’S INTERIOR ENERGY
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The Earth’s rock layer is broken
into pieces that are in constant slow motion.
From time to time, the pieces lock together,
and energy that accumulates between the
pieces may be suddenly released.
 It travels through the Earth in the form
 of waves.
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People on the Earth experience an earthquake.
EARTHQUAKES
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An earthquake is the result of a sudden release
of energy in the Earth’s crust that creates
seismic waves.
These seismic waves transfer mechanical energy.
EARTH’S INTERIOR ENERGY
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A volcano is an opening in the Earth’s crust
which allows hot magma to escape from below
the surface.
VOLCANOES
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A volcano is a release of energy that built below
the surface of the Earth due to heat and
pressure.
Flowing magma transfers heat and mechanical energy.
EARTH’S CHANGING SURFACE
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Small changes over time add up to major
changes on Earth’s surface.