The symbol

1
INTRO
These slide-shows are all on the Prepwork folder
if you wish to copy any notes from them we will
not be stopping in class for you to do this
The symbol
means copy the text on this slide.
2
INTRO
The Ice Age was a series of advances and
retreats of the icecaps. It lasted from 1.7
million years to 10,000 years B.P.( before
present) Most of Britain was glaciated as far
south as the Severn-Thames line.
3
INTRO
Glaciers form in areas of permanent snow called
snowfields.
These occur at high altitudes, latitudes nearer
the poles and often on the colder, north-facing
slopes.
4
INTRO
Ice erodes in the upland areas using three main
processes and creating the features shown on page
27 of the booklet.
The products of erosion- moraine and other
material- are transported to lower ground where
they are deposited in areas in specific shapes.
This creates the features shown on page 37 of the
booklet
5
EROSION
PROCESS 1 Freeze-thaw/ frost shattering

• Water from melted snow collects in cracks and
  crevices in rocks above glaciers.

• Water expands when frozen and forces the crack
  wider. When it warms, ice melts and the wider
  crack can hold even more water.
• After several sessions, the rock shatters.
• Sharp, angular pieces of rock called scree fall
  to the foot of the slope.

• At night temperatures drop below freezing and the
  water changes into ice.

6
EROSION
PROCESS 2-Plucking

• Glacial ice freezes into the cracks and crevices
  made by the freeze-thaw process and as the
  glacier moves, loose pieces of rock are pulled or
  torn out.

7
EROSION
PROCESS 3-Abrasion
Abrasion occurs when pieces of rock debris that
are embedded in the ice rub away at the rocks on
the valley floor and sides like sandpaper.
8
EROSION
Striations are scratches made on the existing
surface by rocks that are embedded in the bottom
of the glacier as it moves forward.
The rock is scratched, polished, smoothed and
eventually worn away by the scouring action.
9
EROSION
Read pages 25 and 26 of the booklet, and use it
and the previous notes to un-jumble the following
heads and tails. There is only one best fit
answer! The tails are one line long.
a). Freeze-thaw process results in b). Plucking
results in c). Abrasion results in d). Rock
flour is the result of f). Angular rock
fragments result from
10
EROSION
jagged rocks. plucking and frost
shattering. frost shattered rocks. abrasion. sm
ooth rocks with striations.
END