A step in time
In 1998 Richard Fortey gave us Life: An Unauthorised Biography. Now we have his Intimate History of the Earth. In both he leads us into the interstices of subjects which few have so far been willing to see as a whole. He does so with skill, eloquence and an endearing lightness of touch that makes them indeed seem unauthorized and intimate, yet serious at the same time.
Geology occupies a special place in the history of science. From the end of the 18th century to the middle of the 19th, it was the driving force in stretching time and space in the human mind. Chronology based on the Bible was superseded, not without pain. The arguments of the catastrophists and uniformitarians may seem entertainingly artificial today, but as in many ferocious disputes there were elements of rightness and both sides.
Darwin was profoundly influenced by the work of such geological pioneers as Hutton and Lyell, and ideas about the evolution of life proceeded naturally from those about the evolution of the Earth. The discovery of radioactivity led to radical revision of its estimated age, from less than a hundred million, to more than 4,500 million years. The next ferocious dispute arouse in the 1960s and 1970s over the movement of what are now called tectonic plats, the continuing transformation of the Earth's surface. In Fortey's words, geology acts as a kind of collective unconscious of the world, which affects all we think or do.
The surface which looks so stable is in fact a jigsaw of constantly moving parts. Their speed is variable, but a useful analogy is that of the growth of a human fingernail. Few things happen soon. I remember wonderingly standing with one foot on each side of the crack which is the famous San Andreas fault in California, and later descending into that part of Ethiopia below sea level where the sea will eventually pour in.
The pressure of plates on each other and their division in such places as the Mid Atlantic Ridge can push up mountains, create deep fissures above and below the sea, reshape and reorient continents, and slide unlikely deposits on top of each other, thereby confusing nice sedimentary sequences. To understand the engines driving this apparatus, we have to look deep: below the crust, below the lithosphere, below the mantle, and through the liquid to the solid core. Then of course there are occasional hits from space, ranging from that which disposed of the dinosaur family 65 million years ago to that which destroyed Siberian forests in 1908.
Already the long past looks very different. We can now imagine the days when the Mediterranean was a series of inland lakes, the Scottish and Appalachian mountains were joined, the Himalayas had not yet risen, Madagascar was part of Africa, Antarctica was north of the equator, and so on back into configurations yet to be worked out. We can also discern some of the future: a widening Atlantic, a shrinking Pacific, and the movement of Australia to the North-East.
In all this Fortey is an admirable guide. He builds his arguments from personal experience of particular places, whether Vesuvius, Hawaii, the Alps, Newfoundland or the Persian Gulf. As he puts it, it is a dance to the movement of time. Anyone who descends the Grand Canyon and sees the layers of Earth history stacked at angles on either side can catch something of the dance. Even England, with its succession of layers from recent in the East to ancient in the West, can feel a little mobile, and the curvaceous strata of Lulworth Cove in Dorset are enough to induce giddiness. I can think of no better dancing companion than Fortey to explain each step. My only reproach is that we could have done with a few more maps.
The book is not of course confined to geology. Fortey links his intimate history with the evolution of life, with its marker fossils at most stages, and the development of human society. Even if we human mites of the surface are usually unaware of what goes on below (and likewise of what goes on above), geology is indeed the basis of our economies, our cities and the conduct of our lives.
Fortey concludes with a ride around the Earth in a kind of celestial helicopter to see the picture as a whole. In doing so the pilot seems to miss the equatorial bulge which I believe makes the highest mountain measured from the centre of the Earth Chimborazo in the Andes rather than Everest in the Himalayas. But he misses little else. Indeed he brightly illuminates the world we know, and enriches our understanding of its past and future. Enjoy this remarkable book.
