Download Folding and Faulting Types of Rocks

Folding and Faulting
Types of Rocks
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Igneous Rocks: form when molten lava
(magma) cools and turn to solid rock.
The magma comes from the Earth’s core
which is molten rock. E.g. Granite and
Basalt.
Sedimentary Rocks: are formed due to
compaction and sedimentation of grains in
a pile of sediments. This type of rock has
layers. E.g. sandstone, limestone, shale etc.
Metamorphic rocks: are formed from preexisting rocks. E.g. Marble
Rock cycle
Rocks can
change shape
due to stress
Three types of stress:
Compression
Tension
Shear
FOLDING
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Rocks under enormous heat and pressure can
slowly bend without breaking. this is how
rocks form folds.
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Geologists use the terms syncline and anticline to
describe downward and upward folds in rock
An anticline is a fold in a rock that arcs upward.
A syncline is a fold in a rock that arcs downward.
Draw diagram yourself of an anticline and
syncline
Important minerals are found near fold such as
gold (at Bendigo in victoria) and oil.
FAULTS
FAULT: is the line along which
rocks break and move.
 Faults occurs when the rock
cannot withstand enormous heat
and pressure.
 Important minerals and oil can
usually be found along fault
lines.
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Normal Faults
 Caused
by
tension forces
 Upper block
moves down
relative to
lower block.
Reverse Faults
 Caused
by
compression
forces
 Upper block
moves up
relative to lower
block.
 Draw fig26
pg.148
Reverse Faults
Caused
by
compression
forces
Hanging
wall moves
up
Strike-slip Faults
Opposing
forces
cause rock to
break
Move horizontally