I first came across the phrase ‘deep time’ in a pair of books I copy-edited for the Geological Society in 1998. I realised at once that Deep Time had to be the title of the novel I’d recently started writing.
The two books were Lyell: The Past Is the Key to the Present edited by Derek J. Blundell and A.C. Scott and James Hutton: Present and Future edited by G.Y. Craig and J. Hull. They were published in celebration of the bicentenary of the death of James Hutton and the birth of Charles Lyell (pictured), the two Scottish geologists who discovered the concept of deep time – the idea that the earth is not thousands but many millions of years old. The radioisotopes today used to date rocks were unknown to them; their theories were based on observing processes like sedimentation and erosion and estimating how long it would take such processes to produce the huge thicknesses of sedimentary strata.
I never heard the term ‘deep time’ in three years of studying earth sciences at Cambridge. It was the mid 1980s and, though the concept of deep time was long known, the term itself was only coined by John McPhee in 1981 and I guess took a while to catch on. Since 1998 the phrase has become increasingly trendy, especially since 2006 when I started submitting portions of Deep Time to agents and publishers. So maybe I’ve already contributed to the term’s currency, or maybe I’ve just converged with the zeitgeist!
For a long time the big deal about deep time was the challenge it posed to biblical interpretation that clung to the idea the earth was only 6000 years old. This line of debate has bored me since I was an undergraduate. The evidence for deep time is beyond question, unless God deliberately sought to deceive us by fabricating an illusion of it. But deep time has a new relevance for today’s global ecological crisis. It puts the speed at which humankind is transforming the earth’s ecosystems into the context of the time it took those ecosystems to come into being, and so helps us understand that human activity has become a geological force of nature.