Geoscience Reference
In-Depth Information
Chapter 2
Deep time
Space is big, really big . . . You may think it's a long way down the street to
the chemists' but that's just peanuts to space.
Douglas Adams,
The Hitchhiker's Guide to the Galaxy
The world is not only large in its spatial dimensions. It also extends almost unimaginably
far back in time. It is impossible to get a full grasp of the concepts and processes at work
in geology without an understanding of what writers John McPhee, Stephen Jay Gould, and
Henry Gee have referred to as deep time.
Most of us know our parents, many remember our grandparents. Only a few have met great
grandparents. Their youth lies more than a century in our past, a time which seems alien to
us with our vastly different scientific understanding and social structure. Just a dozen gen-
erations back, England was ruled by Queen Elizabeth I, motorized transport and electronic
communication was undreamt of, and Europeans were exploring the Americas for the first
time. Thirty generations takes us a thousand years back, before the Normans invaded Britain.
It is also before continuous written records are likely to be able to trace our direct ancestry.
We may be able to tell from archaeology and genetics roughly who our ancestors were at
this time and where they might have lived but we cannot be certain. Fifty generations ago,
