|
(Continued)
|
Outline
of the last great glaciation
|
| Years
ago before present time |
Effect |
| 5th
Period |
13,000 |
|
| |
20,000 |
Scottish
higland re-advance |
| |
30,000 |
|
| |
60,000 |
Scottish
and Welsh advance |
| |
95,000 |
|
| |
125,000 |
Hunstanton
glaciation |
|
INTERGLACIAL-WARM
PERIOD
|
| 4th
Period |
235,000 |
Gipping
Till |
| |
360,000 |
Great
Chalky Boulder Clay |
|
INTERGLACIAL-WARM
PERIOD
|
| 3rd
Period |
670,000 |
Lowestoft
Till |
| |
780,000 |
Lower
Chalky Boulder Clay |
|
INTERGLACIAL-WARM
PERIOD
|
| 2nd
Period |
900,000 |
|
| |
1,150,000 |
|
|
INTERGLACIAL-WARM
PERIOD
|
| 1st
Period |
1,370,000 |
|
| |
1,600,000 |
|
|
The
first and the second of these glacial periods had very little
effect on the landscape of East Anglia. The third (fig.
3a), however, happened approximately 780,000 years ago and
lasted for some 90,000 years; and between this time and
that of the last great glaciation to affect this area (the
fourth, fig 3b), which took place between 235 and 360 thousand
years ago, the area was covered by a vast blanket of chalky
boulder clay. This material was the result of the glaciers
grinding away at the material they þowed over, which
was picked up, carried by the glaciers and then deposited
once the glaciers melted. This covered a very large area
in front of the glaciers and varied in thickness, usually
between 30 and 50 metres, but in the south west of Suffolk
thicknesses between 50 and 75 metres have been recorded,
though you can't tell that from the surface.
|
Fig
3. Direction of Ice movement: A Lowestoft and B Gipping.
--- Ice Front |
|
|
