This is a mindmap about rocks, erosion and much more. Not everyone likes long boring mind maps so I made one with short snippets of facts on it, it might not have long paragraphs but it still contains lots of great information especially for GCSE Geographers :) I hope it helps!
They are rocks that are
changed due to
heat/pressure
Usually formed from layers or
bands of crystals that are very
hard
Resistant to erosion
How are they formed?
Earth movements can sometimes cause rocks
to be deeply buried or squeezed. They are put
under a lot of pressure and heat, they DO NOT
melt but they change chemically
They can be formed from
sedimentary or igneous rocks
Examples
Slate
Marble
Igneous Rocks
How are they formed?
Magma from inside the Earth erupts and cools on
the surface of the Earth- extrusive rocks. Or magma
cools inside the Earth to form intrusive rock which
may be exposed to weather and erosion later. As
the magma cools it forms rocks made of crystals.
Examples
Basalt
Granite
Characteristics
More resistant and doesn't erode easily
Contains randomly arranged
interlocking crystals. The crystal
size depends on how long it took
to cool, the slower the rate of
cooling the larger the crystals
They do not contain fossils
Sedimentary Rocks
Characteristics
Contain rounded grains
in layers. The oldest
layers are at the bottom
and the youngest are at
the top.
May contain fossils of animals
and plants from when the
sediments formed
Erodes more
easily
Examples
Mudstone
Shale
How are they formed?
Sediments get transported and
deposited these include rocks and
skeletons. These sediments get
compacted and compressed, due to
this pressure, sedimentary rock is
formes
This is called Lithification
Weathering
What is the Coast?
The coast is a narrow zone
that connects the land and
see, the coastline sometimes
changes due to weathering.
What is weathering
Weathering is the breaking down of
minerals or rocks on the Earth’s surface this
could happen because of chemical, physical
or biological reactions taken place.
The three main types of weathering
Mechanical: Freeze-Thaw weathering
is when water gets into cracks of
rocks. It then freezes and expands and
then the process starts again during
the process fragments of rocks may
fall off
Chemical: Rain water is slightly
acidic and reacts with certain rock
types. Limestone is made of
carbonates and will disintegrate in
acid.
Biological: This weathering occurs
because of plants or animals.
Plant roots or burrowing animals
can break up rocks
What can affect weathering?
The structure of the
rock: (how soluble or
stable it is.)
The climate of the area: heat
speeds up a chemical reaction so in
warm, humid climates chemical
weathering is more common. In
cold, dry climates physical
weathering is more common.
Human
Activity:
Pollution
Mass Movement
Slumping
Rain seeps through permeable rock.
At the junction where permeable
rock reaches the impermeable rock,
the saturated soil and the weaker
rock slump in a rotational manner
along a curved surface.
Sliding
The movement of material occurs along a
flat surface, usually a bedding plane. Large
amounts of rock and soil can move
downslope rapidly and can cause a lot of
damage.
Rock Fall
A sudden form of mass movement.
Fragments of weathered rock from the
cliff face fall under gravity and collect at
the base.
Coastal Erosion
Hydraulic Action
The sheer power of the waves as they
smash against the cliff. Air becomes
trapped in the cracks in the rock and
causes the rock to break apart.
Abrasion
This is when pebbles grind
along a rock platform, much
like sandpaper. Over time the
rock becomes smooth and
round.
Solution
This is when seawater
dissolves certain types of
rocks. In the UK, chalk and
limestone cliffs are prone
to this type of erosion.
Attrition
This is when rocks that the
sea is carrying knock against
each other. They break apart
to become smaller and
more rounded.