BOOK REVIEW
A Restless Planet
Michael Novacek
Earth: An Intimate History. Richard Fortey. xii + 429 pp.
Alfred A. Knopf, 2004. $30.
Richard Fortey's new magnum (dare I say magma?) opus,
Earth: An Intimate History, is a hefty volume encased
in a dust jacket with a metallic tint somewhere between copper and
bronze. From a distance the book resembles one of those marvelous
rocks that Fortey so enthusiastically smothers with attention in the
text. The center of the front cover has a small circular cutout
(obviously iconic for the spherical Earth), which serves as a window
onto an old lithograph that shows Mount Vesuvius erupting (one of
several striking images on the front of the binding). The effect is
arresting and beautiful (hats off to designer Peter Mendelsund), a
perfect complement to Fortey's stated purpose of enlightening
readers about plate tectonics by showing "how the lie of the
land responds to a deeper beat."
Every rock, whether copper-veined, silver-clad, black-glazed or
imbued with olivine green, tells a story about the Earth as a whole.
This connection was made first by Charles Lyell in the 1830s and
later by his successors, who used what they learned from visits to
Vesuvius, the Alps and other magnificent terrains to fashion a
theory of the Earth. Of course, as Fortey describes, these early
connections made between rock, region and Earth process were later
transformed and fortified, becoming the modern theory we call plate tectonics.
Like the complex crust of Earth itself, Fortey's book is a
mosaic—part history, part travelogue and part geological
survey—which moves us with him around the globe and into
Earth's interior. Fortey describes the "Temple" of Serapis
near the Bay of Naples, where Lyell in 1830 challenged a static
concept of the Earth with a simple observation: He noted that the
borings in the midsection of the marble columns there were
apparently caused by rock-eating marine clams, indicating the rise
and fall of the sea and the ups and downs of a dynamic crust over
vast stretches of time. Fortey calls Serapis a geological "holy
place for rationalists," recognizing the oxymoron: The scarred
columns evoke a rational explanation that defies many a religious
conviction about the biblical brevity of Earth's history.
Fortey continues his pilgrimage to other "holy
places"—the shield volcanoes of the big island of Hawaii;
the spectacular overturned strata, or nappes, in the Sernft Valley
of the eastern Alps; the ancient schists of Newfoundland and, of all
places, Central Park in New York City; the Ellora temples (literally
a holy place) within the Deccan lava deposits in India; the San
Andreas Fault; the Grand Canyon; and the laboratories of Bristol
University, where conditions in the Earth's interior are quite
credibly reproduced experimentally.
Not content with these wanderings, the author in his last chapter
takes us on a wobbly orbit around the planet to witness from afar
some of the great plate features at the proper scale. Along the way,
he lands at various spots to reminisce about his searches for
trilobites and other fossils. These excursions reminded me that a
widely published survey showed that geologists were among the most
satisfied professionals. Who wouldn't be, with so much of the world
as your oyster?
Geology was revolutionized by plate tectonics—an enviable
change (scientists in many other fields would like to see their
disciplines similarly transformed). Yet this grand unified theory of
Earth processes is now rather well established—nay, aged.
Fortey worries that "it is difficult to record the growth in
comprehension of the earth in the light of plate tectonics without
occasionally sounding smug. 'Aren't we the clever ones?' we seem to imply."
Indeed, our enthusiasm to embrace these explanations can tempt us to
trivialize a great void in understanding: Although the effects of
plate tectonics on mountain building, island emergence, trenching
and faulting are manifest, the basic mechanisms literally underlying
plate shuffling are still only partly understood. Fortey asks the
yet unanswered questions: What is the energy source for the Earth's
magnetic field? Does the mantle contain two sets of convection cells
of fluid rock or only one? The inner workings of our home planet,
the processes that determine the architecture of the deep mantle and
the core, are less observable to us than the atmospheric
fluctuations of a distant star. Unlike travel into deep space, a
journey to the center of the Earth seems all but impossible. The
closest we may get are those high-pressure, high-temperature
chambers at Bristol or other research labs.
Not that a dissection of the crust itself is always that easy.
Fortey beckons us to the epicenter of tortuous stratification, the
Alps. The place is utterly complex, and so is the narrative, full of
folding, tilting and overturning. There are also collisions: those
between plates and those between ideas and personalities—the
likes of Arnold Escher and Albert Heim, and their antagonist, the
ultimately triumphant Marcel Bertrand. Our scrambles in the Alps
eventually, albeit circuitously, lead us southward to Italy, to a
fault (the Insubric Line) and a modern conclusion: that all this
complexity is the result of a great plate collision. Africa, or more
properly the splintered-off Adriatic plate, has been pushing against
"obdurate Europe" for tens of millions of years. The upper
part of the Matterhorn is actually "a part of 'Africa' thrust
bodily northwards over Europe."
On this meandering journey we sometimes lose the connection between
rocky visages and the bigger picture. Yet there are also crystalline
explanations. We explore Via Mala—a slitlike defile so narrow
that only one traveler at a time could trace its gloomy medieval
footpath. Fortey tells us that the uniform character of the limy
schists that form the canyon walls ensured this oppressive
narrowness. "It is as if the river acted in the manner of a
circular saw cutting into a particularly dense log of teak," he
says. "The gorge maintained its vertiginous integrity as the
mountains were delivered into the jaws of erosion."
In the Alps we also encounter Eduard Suess (1831-1914), clearly one
of the giants of geology. Suess moved beyond Lyell to embrace the
complexity of regions like the Alps as part of a bigger pattern of
crustal upheaval. We then follow Suess to the Great Karroo in South
Africa, and we are startled by his prescient observations. The
similarity of ancient rocks and their fossils in Africa to those in
South America and peninsular India suggested to him that these
continents and subcontinents were once unified, forming a land Suess
called Gondwana. Fortey is clear about the impact of this insight:
"It was the acceptance of the existence of this vanished land
that set the seal on modern geology." Of course, Suess is in
good company, sharing the credit with such successors as Alfred
Wegener, Alex du Toit and, much later, Arthur Holmes, whose rough
sketch of continental drift and seafloor spreading, published in
1931, may be the most important illustration in the history of geology.
Fortey moves us to the churning present, ticking off breakthroughs
allowed by new technologies for dating rocks, measuring magnetism,
drilling the crust and mapping the seafloor. Casting his net broadly
here to reach a diverse readership, he presents an extraordinary
compilation of evidence, tests designed to find holes in
plate-tectonic theory that in the end only reconfirmed the concept.
Students taking a basic college course in geology should put down
their textbooks for a moment and read Fortey's riveting account for
clarity and inspiration.
Fortey's mid-route summary of plate-tectonic theory is a high point
of the book, but what remains is anything but anticlimactic. For
example, a chapter that delightfully blends history, commerce,
precious minerals and plate tectonics informs us that the word
dollar comes from the Dutch word daler, a variant
of thaler, the one-ounce silver coin used widely in
16th-century Europe. The silver to make thalers was churned out at
the great mine at Joachimsthal (now Jachymov, in what is now the
Czech Republic). Why was this eastern European realm so
providentially enriched? The mines are on one end of an ancient
range—the Hercynian, or Variscan, fold belt, which extended
through the midsection of continental Europe, terminating in the
western tip of England, where mines produce more tin, lead and zinc
and less silver. The range itself is, of course, the product of an
earlier plate impingement, one that long preceded the rise of the
Alps—the subduction of the Rheic Ocean, which once divided
what is now Europe.
If Fortey's narrative has a fault, it's that it left me wanting
more. I was fascinated by Doris Reynolds and her valiant battles
with her many chauvinistic male colleagues in the great Granite
Controversy of the 1930s, '40s and '50s. Thus I was surprised that
Fortey, in his discussion of the San Andreas Fault, failed to
mention the pivotal work of another extremely important woman
geologist, the still very active Tanya Atwater, who explained the
fault as an expression of the immense, laterally sliding boundary
between the Pacific and the North American Plates. I wanted to know
more about meteorites and the clues to the deeper layers of our own
planet offered by the bits that they carry from the core of
shattered planetoids.
Despite these wants, there is much that glitters within this
copper-clad volume. Fortey tells a story of the Earth that is
scientific, poetic (he quotes Seamus Heaney and D. H. Lawrence) and
certainly passionate. The book is a fitting tribute to our restless home.