EARTH

A senior paleontologist at London's Natural History Museum looks at the new geology, offering an overview built around visits to exemplary sites.

Fortey (Trilobite!, 2000, etc.) begins with volcanoes. The Vesuvius eruption that buried Pompeii in a.d. 79 may have been the first scientifically documented geological event. Nearby, the columns of the Temple of Serapis show evidence of having sunk below sea level, then risen to their current elevation due to the movement of the Earth—a fact that gave Charles Lyell the early clues on which scientific geology was built. Hawaii is another volcanic terrain, with the movement of plates beneath the ocean floor clearly marked by the chain of islands and submerged sea mounts that make up the Hawaiian group. In the Alps, the collision of two plates has raised up a mountain range; the author shows us where and how the different strata have slid past one another. In each location, he combines local color and the history of geology itself with a guided tour of the rocks that result from the processes at work, gradually building up a coherent description of how the theory of plate tectonics emerged to account for the world we see around us. It is at the edges of plates that the majority of the action takes place; there, precious metals collect, melted out of lesser rocks by the heat of the magma seeping up through the joints in the crust. In other sites, geology finds evidence that former continents have been split apart: the rocks that constitute the Appalachian mountain chain extend through Newfoundland, then jump the Atlantic to Scotland and Scandinavia. These lands must, in the remote past, have been joined. Fortey shows the evidence, summarizes the arguments, and does everything he can to put a human face on a science that builds whole worlds over a span of billions of years.

A virtuoso performance. (32 pp. color photos; 58 halftones throughout)