Annals of the Former World

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Annals of the Former World Page 76

by John McPhee


  Rising from the Plains is primarily about Wyoming, which includes within its borders an exceptional range of geology. It’s about the roadcuts of the interstate but also about Jackson Hole and the Tetons and the Powder River Basin and the Wind River Basin and the Laramie Range and David Love and his father and especially his mother, who educated her children at Love Ranch, a very long ride from neighbors, in the geographical center of Wyoming. She was born in 1882 and died long before I would have had a chance to meet her, but she is probably the most arresting personality I have encountered in the course of my professional work. You will find the story of the Laramide Orogeny—the rising of the Rocky Mountains—, the burial and exhumation of the Rockies, a set piece on the geologic history of Jackson Hole and the Tetons (understand a fragment …), and a set piece on the theory of geophysical hot spots (such as Yellowstone, Hawaii, Bermuda, Iceland, Tristan da Cunha, Mt. Cameroon), preceded by a passage on the tension between field geology and “black-box geology”.

  Sometimes it is said of geologists that they reflect in their professional styles the sort of country in which they grew up. Nowhere could that be better exampled than in the life of a geologist born in the center of Wyoming. The passages on Love Ranch and the years of David Love’s upbringing.

  In the unspectacular setting of Rawlins, Wyoming, a person can see in one sweeping glance a spread of time far greater than the time represented in the walls of the Grand Canyon. A verbal rock column reaches down at Rawlins through those 2.6 billion years.

  The final sixth of Rising from the Plains is an environmental montage of tensions between geological discovery and environmental preservation. David Love, exploration geologist and passionate defender of wild Wyoming, contains within himself the essence of the struggle, as it is exemplified by coal, oil shale, trona, oil and gas in the Overthrust Belt, oil in Yellowstone Park, and—one of his signal discoveries, close to home—sedimentary uranium.

  Assembling California came thirteen years after Basin and Range, and the wait was prudent, for, as every grandchild knows, California is challenged only by Alaska as a national showcase of active tectonics. I had scarcely begun writing Assembling California when, in 1989, the Loma Prieta earthquake occurred, and inserted itself with prominence in the text. In 1992, other temblors took place at Big Bear, Landers, and Joshua Tree, the latter two evidently initiating a new fault line and confirming a prediction made in Basin and Range by Ken Deffeyes.

  Assembling California begins and ends at the same point on the Pacific Coast, and in what amounts to a long and digressive flashback traverses the state east to west in the company of Eldridge Moores, whose tectonic hypotheses are on the applied outer boundary of the theory of plate tectonics, where he reconstructs former worlds. When Anita Harris, in In Suspect Terrain, alludes to “the plate-tectonics boys,” the group would include Eldridge Moores. He has suggested, for example, that Arizona and Antarctica were once conjoined. This did not prevent the Geological Society of America from electing him its president in 1995. The simple itinerant structure of Assembling California includes two long set pieces—one near the start and the other near the finish—illustrating the extensive effects of two very different geological events: the gold rush of the eighteen-forties and fifties and the Loma Prieta earthquake, of 1989.

  Moores is an ophiolitologist, an expert on ocean-crustal rock, which asks or answers large questions when it is found detached and lying on continents. An introduction to the nature and complexity of ophiolites is followed by subflashbacks to Cyprus and Greece, where Moores has done research for decades and where transported rock of the ocean floor stands as mountains. With the exception of some veneer, this is not sedimentary rock derived from continents and laid down in the sea; this is igneous rock from magma chilled at ocean spreading centers, and rock of the mantle below. A large piece of it, an exotic terrane, is a part of California known in geology as the Smartville Block.

  Son of a gold miner, Moores grew up in the almost alpine setting of Crown King, Arizona, and now lives in the Great Central Valley of California, whose geologic story has few (if any) parallels among valleys of the world. The Coast Ranges, with their own odd story, are only a few miles west of Moores’ home in Davis. A long set piece on world ophiolites and global tectonics—a narrative of maps in motion, of evolving and dissolving lands, including every plate and continent—is the result of a heady conversation in the Louis Martini winery in the Napa Valley.

  San Francisco geology is introduced in the roadcuts of the approaching Interstate 80 and pursued on foot among the hills of the city. A set piece that traverses California the long way, north-south, is about the San Andreas system, which is actually a family of faults. Among them is the Hayward Fault, which could be a source of considerable trauma for San Francisco, Oakland, Berkeley, and all other Bay Area cities, not to mention Hayward.

  Crossing the Craton describes Nebraska by visiting Colorado, because in Colorado you see the basement of Nebraska bent up into the air. The fact that the journey takes place in the company of a geochronologist from the University of Kansas can only enhance the description. Between Chicago and Cheyenne, the most arresting geophysical feature is the Midcontinent Rift, which opened about a fourth of the way back through the history of the earth—1.1 billion years—and serves as an abyssal edge for a look down through deeper and deeper time. The oldest rock yet found on earth has an age close to four billion years, some six hundred million years younger than the earth itself. After reaching back to the earliest beginnings, the story turns around and comes forward through the Archean Eon, while island arcs accrete and small cratons form. At the end of the Archean, in the very general neighborhood of 2.5 billion years before the present, great and unrepeatable changes occur in the behavior of the earth, including the precipitation of banded iron and the beginning of modern plate tectonics.

  In the early Proterozoic Eon, seven small cratons collide, conjoin as the Canadian Shield. Younger island arcs eventually drift in and dock against the shield, forming large parts of Nebraska and Colorado. These novel views into Precambrian eons are the result of advances in radiometric dating and, among other things, the measurement and interpretation of magnetic and gravity anomalies, all of it anchored and restrained by well cores.

  More arcs accrete. A coastal plate boundary like the Andean margin of South America develops along what is now a northeasterly trend through New Mexico and Kansas. About halfway through the Proterozoic, a baffling series of great plutons (each analogous to the Sierra Nevada batholith of relatively modern times) perforates North America from one side to the other and is mysteriously unaccompanied by the building of mountains, as plutons generally are, almost by definition.

  A time line at 1.1 billion years comes in from the eastern and western margins of the continent and converges in the active and growing Midcontinent Rift. When the spreading stops under Iowa, the granites of Pikes Peak almost unaccountably appear in Colorado, the last tectonic event in Precambrian North America.

  An editor from whose counsel I have benefitted since the early phases of this project is Sara Lippincott, of Pasadena, California, who left The New Yorker in 1993 in order to become a free-lance editor of books. When Sara lived in New York, her idea of a perfect vacation was to get in an airplane and visit Caltech. She did that often. Now that she lives in Pasadena, she teaches at Caltech (a writing course). And from the beginning of Basin and Range to the Pikes Peak conclusion of Crossing the Craton, Sara has been the editor of this book. In the twenty years following the first journeys that are described here, professional attitudes toward plate theory evolved in different ways. The text, as it evolved, reflects that, and in preparing it for comprehensive publication we have attempted to preserve the sense of growing acceptance. Elsewhere, we have freely added material, adjusted the time scale, and tried to keep pace with the constant refining of radiometric dates. The text has been meshed, melded, revised, in some places cut, and everywhere studied for repetition. For the most part, I ha
ve eliminated the repetitions, but I also chose to modify some of them and simply leave others standing. Reminders and repetitions can be as useful in this subject as they are in ballads. Rock carries its own epithets, its own refrains. In it, you see things happening again, and now again. Annals of the Former World in selected places echoes what it has said before. Diapirs are redefined; plate theory is repeatedly and in different ways explained. “Geology repeats itself!” Anita Harris likes to say. Anita likes to say it so much that after a minute or two she says, “Geology repeats itself!”

  For convenience, this should repeat itself, too. To wit:

  JOHN McPHEE

  Farrar, Straus and Giroux

  New York

  by John McPhee

  Irons in the Fire

  The Ransom of Russian Art

  Assembling California

  Looking for a Ship

  The Control of Nature

  Rising from the Plains

  Table of Contents

  La Place de la Concorde Suisse

  In Suspect Terrain

  Basin and Range

  Giving Good Weight

  Coming into the Country

  The Survival of the Bark Canoe

  Pieces of the Frame

  The Curve of Binding Energy

  The Deltoid Pumpkin Seed

  Encounters with the Archdruid

  The Crofter and the Laird

  Levels of the Game

  A Roomful of Hovings

  The Pine Barrens

  Oranges

  The Headmaster

  A Sense of Where You Are

  The John McPhee Reader

  The Second John McPhee Reader

  Index

  The index that appeared in the print version of this title does not match the pages of your eBook. Please use the search function on your eReading device to search for terms of interest. For your reference, the terms that appear in the print index are listed below.

  Aar Glacier, Switzerland

  Abelson, Phil

  Absaroka Range, Wyoming

  abyssal plans

  abyssoliths, see batholiths

  Acadian Orogeny

  accretion tectonics

  accuracy vs. precision

  Acropolis: geology of as klippe

  Adam, Robert

  Adriatic Plate

  Africa: and Brazil cratons in Cretaceous period and Europe geologic history Jurassic proximity to South America and Madagascar in Mississippian period and North America in Precambrian time and Seychelles in Triassic period

  African Plate

  Agassiz, Jean Louis Rodolphe: theory of continental glaciation in United States view of The Origin of Species

  Agassiz’s Club

  Agricola, Georgius

  Alaska: amount of ice in Pleistocene epoch amount of ice today Brooks Range as exotic terrane glacial erratics in origins of Seward Peninsula as suspect terrane Yukon gold

  Alberti, Friedrich August von

  Aleutian Islands

  Aleutian Trench

  Alexander Terrane

  Alleghenian Orogeny

  Allegheny Plateau

  alluvial fans Great Central Valley

  Almadén winery: on San Andreas Fault

  alpine glaciers “ghost glaciation,” observable movement in Sierra Nevada in Switzerland in Tetons see also continental glaciation

  Alps: formation of peridotites in

  Alvarez, Luis

  Alvarez, Walter

  Amazonian Craton

  American Association of Petroleum Geologists : and Anita Harris and continental-drift hypothesis maps by

  American Geological Institute

  American Geophysical Union

  American River, California: dam site near Auburn discovery of gold

  Ames, Oakes

  Ames, Oliver

  amphibolite

  Ancestral Rockies

  Andes: andesite in lack of ophiolites in origins of

  andesite: vs. diorite vs. granodiorite naming of in Sierra Nevada

  angular unconformities: Carlin Canyon, Nevada in Scotland

  anorthosite

  Antarctica: amount of ice in Cretaceous period and India and North America

  Antarctic Plate

  anthracite

  anticlines: Cat Creek Anticline Davis Anticline in Great Central Valley sheepherder anticlines see also synclines

  Antioch Fault

  Antler Orogeny

  Apollo Object

  Appalachians: Ancestral and Delaware Water Gap described formation of Great Valley of the Appalachians on I-80 in late Pennsylvanian maps of orogenies and plate tectonics in Precambrian time as remains of alpine massif remnants in Newark Basin rivers in role of hot spots seismological data study by early geologists in Triassic period

  Archaeopteryx, Jurassic bird

  Archean cratons: collisions between defined map of mineral deposits in Wyoming craton

  Archean Eon: Africa in characteristics of island arcs life-forms in methods of venting heat study of tectonics in transition to Proterozoic Eon

  arc rocks, see island arcs

  argon/argon dating

  Arizona: geology of Moores’ mining background

  Arkansas River gorge, Colorado

  Armstrong, Richard

  Arthur’s Seat, Scotland

  artists: and Delaware Water Gap Hudson River School

  Ascension Island: as hot spot

  aseismic slip

  ash, see volcanic ash

  asteroids: Apollo Object

  asthenosphere

  Athens, Greece: McPhee and Moores in

  Atlantic Ocean: creation of

  Atlantis

  Atlas (Greek mythology)

  Atlas Mountains

  atmosphere: changes in

  atomic-absorption spectrophotometer

  Atwater, Tanya

  Auburn, California American River dam site

  auriferous gravels see also hydraulic mining

  Australia: in Cretaceous period movement toward China and plate tectonics in Triassic period

  autochthonous: defined

  Bahamas

  Baja California, see California, Gulf of

  basalt: association with serpentine, gabbro, and diabase in Basin and Range cooling of flood basalts υs. gabbro Hutton’s view of in Triassic New Jersey

  basement: defined see also Precambrian time

  Basin and Range: absence of layer-cake geology animals in characteristics of continental crust in creation of described earthquakes in fault-block tilting fault displacement faulting υs. Great Basin map of silence in silver deposits

  basin-and-range structure: Border Fault, New Jersey, example described reading of see also Basin and Range

  basin fill: in central Rockies impact of water and wind

  basins: in Basin and Range formation of Great Central Valley as example and hot spots Laramide Orogeny in midcontinent oil and gas in pull-apart υs. ranges types of υs. valleys windscoured see also Basin and Range; basin-and-range structure

  batholiths: across North American continent in Colorado creation of defined Pikes Peak Sierra batholith

  Bauer, Georg

  Bautista de Anza, Juan

  Beartooth Highway, Wyoming

  Beartooth Mountains, Wyoming

  Beaver Mountain, Wyoming

  bedding planes: in Great Valley Sequence Holy Toledo cut igneous rock of Palisades Sill tilting in Stansbury Mountains

  Behre, C. H., Jr.

  Bell Spring, Wyoming

  benched throughcuts

  bentonite

  Berea Delta

  Beringer winery

  Bering Sea

  Berkeley Hills, California

  Bermuda: as hot spot

  Berryessa, Lake

  Bezore, Steven

  Bible: Book of Genesis see also religion

  Bickford, M. E.

  Big Hollow, Wyoming

  Bighorn Basin, Wyoming

  Big
horn Mountains, Wyoming

  Big Meadows of the Humboldt, Nevada

  Big Mountain, Pennsylvania

  Big Picture Precambrian time

  Big Sand Draw, Wyoming

  billions vs. millions

  Bitter Creek, Wyoming

  bituminous coal

  Black, Joseph

  blackboards

  black-box geology: defined υs. field geology Werner as antecedent see also laboratory geology

  Blacks Fork River, Wyoming

  blind hot spots

  blind men and elephant (fable)

  blind thrusts

  Block, Harry

  Bloomsburg formation

  Bonneville, Lake dropping of Great Salt Lake as remnant maximum size shoreline terraces as side effect of glaciation

  Bonneville flats

  Border Fault, New Jersey defined as example of basin-and-range structure

  boulders: erratic in Hickory Run State Park jade at Crooks Gap, Wyoming periglacial

  Boundary Waters Area, Minnesota

  Bowring, Samuel A.

  braided rivers

  Brazil: and Africa

  Brazilian Shield

  breccia

  Brevard Zone

  Bridger, Jim

  Bridger (Jim) generating plant

  bridges: George Washington Bridge Golden Gate Bridge and site San Francisco-Oakland Bay Bridge

  Brink, Lambert

  Brooklyn, New York: Anita Harris in geology of

  Brooks Range, Alaska

  Brower, David

  Brunn, Jan

  Buch, Leopold von

  Buckley, William F., Jr.

  buffalo: and Wyoming gangplank

  Buffalo Wallows, Love Ranch, Wyoming

  Burma Syntaxis map of

  Busch Ranch Fault

  Cabot, James Elliott

  Caen, Herb

  Calaveras Fault

  calcium carbonate: and creation of oolites see also dolomite; limestone

 

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