Check out this month's On the Web links, your connection to earth science friendly Web sites. The popular Geomedia feature now available by topic.
Upheaval from the Abyss: Ocean Floor Mapping and the Earth Science Revolution
Geoquotes -- our newest Geomedia feature!
|Upheaval from the Abyss: Ocean Floor Mapping
and the Earth Science Revolution
by David M. Lawrence. Rutgers University Press (2002). ISBN 0-8135-3028-8. Hardcover, $28.
Edward M. Davin
Upheaval from the Abyss is a popular retelling of the emergence of the
theory of plate tectonics. It is written in laymans language and tells
almost as much about the lives of the major players as it does about the revolution
in human knowledge that they achieved. The author David Lawrence is a freelance
science journalist and contributing writer for Geotimes. He appears to
have interviewed all of the major scientific investigators still living. For
anyone still not familiar with the multifaceted story of how this discovery
came about, I cannot think of a better place to begin. I lived through these
times. As a program director then at the National Science Foundation, I worked
with many of the key scientists involved. But when I read Upheaval from the
Abyss, I still found much that was new to me.
As its title indicates, the book is about more than plate tectonics. The author takes the long view of the human quest to understand the history of Earth: the land and the sea, the mountains, the earthquakes, volcanoes etc. He starts his story on Day One of Genesis and leads us through the centuries as man tries to reconcile his observations with The Word of God. This effort at reconciliation was mostly abandoned in the 17th century, but the conviction that the continents and the oceans, once formed, were permanent features of Earth remained steadfast. Another mental barrier that had to be overcome was comprehending the vast expanses of time required for the geological processes. Lawrence describes the paths that early thinkers followed both to dead ends and to the occasional landfall or two. When he must introduce a new concept, such as isostasy, Lawrence patiently walks the reader through the steps.
Curiously, the opening chapter recounts the last days of Alfred Wegeners 1930 expedition to cross the Greenland Ice Cap along the 71st parallel. But perhaps it is not so surprising that Lawrence opens the story with Wegener. He is Lawrences real hero if this story is said to have one. Wegener recognized the striking fit between the east coast of South America and the west coast of Africa. This fit often impressed even the casual observer, but Wegener decided that the continents were once together and formed part of a supercontinent he called Pangaea. Proving continental drift would become his life-long obsession, as he correlated data from both sides of the Atlantic.
His theory, however, ran against the mindset of the scientific community of that time, which was that the continents and oceans once formed were fixed. Perhaps, Wegeners underlying problem was that he was a polymath: his degree was in astronomy, he worked as a meteorologist, as a climatologist. But he was not even a geologist, no less a geophysicist.
During the 1920s, Wegener met the endless objections to his theory and in time published four editions of his book, The Origin of the Continents and the Oceans. Wegeners contemporary Tuzo Wilson made what was to become a prophetic statement: Perhaps the reason that [continental drift] has never been settled is that much more is known about the continents than about the ocean floors, where the decisive evidence probably lies.
Having begun with Wegener, Lawrence goes back again and, in a series of short chapters, traces mans growing knowledge of the sea floor. He begins with the pre-Civil War Naval officer Matthew Maury and his achievement, the 1845 Bathymetry of the North Atlantic Ocean. This writing helped set the stage for laying down the first Trans-Atlantic Cable. Other chapters recount the round-the-world voyage of the HMS Challenger between 1872 and 1876, which made enormous strides in our growing knowledge of complex ocean currents and the diversity of ocean specimens. The Titanic disaster in 1912 showed the need for new technology to protect ships at sea. A major accomplishment was the iceberg detector and echo sounder, an oscillator that could produce clear, powerful sound underwater. Lawrence tells us how these and many more developments came about, and also tells us about the men who produced them.
Maurice Ewing, one of the progenitors of marine geology, dominates the latter half of Lawrences story. He follows Ewings career from very humble origins in Texas to the establishment of the Lamont Geological Observatory, which he directed for more than 30 years. We learn of Ewings insatiable gathering of cores (which Lawrence calls an addiction), of Ewings geophysical measurements from the ocean floors, and his knack for picking the right people to analyze and interpret the data. While working for the U.S. Navy during World War II, Ewing and his life-long colleague Joe Worzel set the stage for the rapid advances in marine geology and geophysics in the late 1940s and 1950s. In fact, many subdisciplines of geophysics developed rapidly out of wartime emergencies. These subdisciplines marine seismic methods, gravity, heat flow, paleomagnetism would converge to establish plate tectonics.
Lawrence has uncovered many intriguing stories. We learn, for example, that Marie Tharp, working at Lamont to compile the bathymetric data of the North Atlantic, recognized that the epicenters of earthquakes line up along the rift valley of the Mid-Atlantic Ridge, evidence that the sea-floor was spreading. Tharps boss was Bruce Heezen, an arch anti-drifter; but Tharps observations helped to convince him to abandon the mindset that the continents and ocean were permanent features of Earth.
Geoscientists then turned to the idea that Earth was expanding. This held until Brian Isacks and Jack Oliver set their seismometers on the Tonga-Fiji Deep Earthquake Project and discovered a thick slab descending (subducting) into Earths mantle. The question of how Earth accommodated new crust created at the mid-ocean spreading centers was then answered. The two processes balanced out. The notion of an expanding Earth died with the discovery.
Lawrence also relates the interpersonal, inter-institutional, indeed international rivalries that inevitably took place as the enormous significance of the research emerged. The book includes some good photos of key maps and of the scientists. The bibliography cites important references for anyone who wants to pursue a special topic. The book is not intended to be a compendium of all the subdisciplines that make up the theory of plate tectonics, but it does embrace most of the story. One will be disappointed, perhaps, not to find an account of the smoking gun (literally) of plate tectonics: the black smokers observed from deep-diving submersibles along the East Pacific Rise in 1979. But this omission is a minor point in what must otherwise be described as a comprehensive, and very readable account of the geosciences Copernican Revolution.
Wherever he is Wegener must be looking on the scene with satisfaction to see his life work finally vindicated.
U.S. Geological Survey
MF-2372. NEVADA and CALIFORNIA. Hydrostructural maps of the Death Valley regional flow system, Nevada and California by C.J. Potter, D.S. Sweetkind, R.P. Dickerson, and M.L. Killgore. Prepared in cooperation with the USDOE, National Nuclear Security Administration. 2002. Scale 1:350,000. Two color sheets accompanied by 12 pages of text. Available free, or for $40 as print on demand.
MF-2373. CALIFORNIA. Geologic maps and structure sections of the southwestern Santa Clara Valley and southern Santa Cruz Mountains, Santa Clara and Santa Cruz Counties, California by R.J. McLaughlin, J.C. Clark, E.E. Brabb, E.J. Helley and C.J. Colón. 2001. Scale for sheets 1-5 is1:24,000; scale for sheet 6 is 1:125,000; sheets 7-8 are structure sections. Eight color sheets accompanied by 13 pages of text. 7.5-minute quadrangles mapped include Los Gatos, Laurel, Loma Prieta, Santa Teresa Hills, the southwestern part of the Morgan Hill on Mount Madonna and southwestern part of the Gilroy. Available free, or for $160 as print on demand.
MF-2374. MISSOURI and KANSAS. Geologic map of the Saint Joseph Area, Missouri and Kansas by W.J. Langer, L.L. Brady, David Smith and R.A. Melick. 2001. Scale 1:63,360. One color sheet available as print on demand. $20.
MF-2377. COLORADO. Generalized geologic map of part of the upper Animas River watershed and vicinity, Silverton, Colorado by D.B. Yager and D.J. Bove. 2002. Scale 1:48,000. One color sheet. Available free, or for $20 as print on demand.
MF-2384. CALIFORNIA. Debris flows triggered by the El Niño Rainstorm of February 2-3, 1998, Walpert Ridge and vicinity, Alameda County, California by J.A. Coe and J.W. Godt. 2001. Scale 1:24,000. Three color sheets. Available free, or for $60 as print-on-demand.
MF-2391. NEBRASKA and IOWA. Surficial geologic map of the Greater Omaha area, Nebraska and Iowa by R.R. Shroba, T.R. Brandt and J.C. Blossom. 2001. Scale 1:100,000. One color sheet. Available free, or for $20 as print on demand.
To order USGS maps: contact USGS Information Services, P.O. Box 25286, Denver, Colo. 80225. Phone: 1-888-ASK-USGS (1-888-275-8747). Maps identified as print-on-demand maps may be downloaded from the Internet, but if you prefer the USGS to run off a copy for you there is a charge as noted above.
Gimli: Strange are the ways of men, Legolas! Here they have one of the marvels of the Northern World, and what do they say of it? Caves, they say! Caves! Holes to fly to in times of war, to store fodder in! When the torches are kindled and men walk on the sandy floors under echoing domes, ah! then, Legolas, gems and crystals and veins of precious ore glint in the polished walls; and the light glows through folded marbles, shell-like, translucent. There are columns of white and saffron and dawn-rose, Legolas, fluted and twisted into dreamlike forms; they spring up from many-coloured floors to meet the glistening pendants of the roof: wings, ropes, curtains fine as frozen clouds; spears, banners, pinnacles of suspended palaces! Still lakes mirror them: a glimmering world looks up from dark pools covered with clear glass; cities stretch on through avenues and pillared courts, on into the dark recesses where no light can come. And plink! A silver drop falls, and the round wrinkles in the glass make all the towers bend and waver like weeds and corals in a grotto of the sea. Then the evening comes: they fade and twinkle out; the torches pass on into another chamber and another dream. There is chamber after chamber, Legolas; hall opening out of hall, dome after dome, stair beyond stair; and still the winding paths lead on into the mountain's heart. Caves!"
Do you have a favorite Geoquote? Please share it with us. Send one by letter
to: Geoquotes, Geotimes, 4220 King Street, Alexandria, VA 22302 or by e-mail
with the subject Geoquotes.
Back to top