Geoscience Reference
In-Depth Information
THREE DIFFERENT TIMESCALES
More recent past events tend to be better known and of greater interest than distant past
events. Figure 6 is plotted on a logarithmic timescale, so that the most recent times are
given more space and greater ages are given less and less space.
FIG
6.
Three different timescales, plotted to give more space to more recent events.
For the purposes of this topic, we can distinguish three overlapping timescales to
help us to understand the landscapes of Southern England:
The
bedrock timescale
(extending from 542 million years ago to about 2 million
years ago)
The
Ice Age timescale
(covering roughly the last 1 million years)
The
last 30,000 years timescale
We shall now review each of these, commenting on the sorts of episodes in each
that are important in our exploration of Southern England.
THE BEDROCK TIMESCALE
Figure 7 is a simplified version of a generally accepted geological timescale relevant
to the landscapes of Southern England. The names of the divisions are universally ac-
cepted in the geological world and, unlike the previous diagram, the passage of time
is represented on a uniform (linear) timescale. The divisions have been selected, and
sometimes grouped, to help in our analysis of the situation in Southern England, and
these have been colour-coded for use in the rest of the topic.
