Nearly every aspect of geology has some economic
or environmental relevance. Many geologists are involved in exploration
for mineral and energy resources, using their specialized knowledge
to locate the natural resources on which our industrialized society
is based. As the demand for these nonrenewable resources increases,
geologists are applying the basic principles of geology in increasingly
sophisticated ways to help focus their attention on areas with a
high potential for economic success.
Although locating mineral and energy resources
is extremely important, geologists are also being asked to use their
expertise to help solve many environmental problems. Some geologists
are involved in finding groundwater for ever-burgeoning needs of
communities and industries or in monitoring surface and under-ground
water pollution and suggesting ways to clean it up. Geologic engineers
help find safe locations for dams, waste-disposal sites, and power
plants and design earthquake-resistant buildings.
Geologists are also involved in making short- and
long-range predictions about earthquakes and volcanic eruptions
and the potential destruction that may result. In addition, they
are working with civil defense planners to help draw up contingency
plans should such natural disasters occur.
As this brief survey illustrates, geologists follow
a wide variety of pursuits. As the world's population increases
and greater demands are made on Earth's limited resources, the need
for geologists and their expertise will become even greater.
Destructive volcanic eruptions, devastating earthquakes,
disastrous landslides, large sea waves, floods, and droughts make
headlines because they wreck many people's lives. Although we cannot
prevent most of these natural disasters, the more we know about
them the better we can predict-and perhaps control the severity
of their impact.
Equally important, but not always as well understood
or appreciated, is the connection between geology and economic and
political power. The distribution of mineral and energy resources
is unequal, and no country is self-sufficient for all its mineral
and energy needs. Throughout history, people have fought wars to
secure needed mineral and energy resources. We need look no further
than 1990-1991 to see that the United States became involved in
the Gulf War largely because of the need to protect U.S. oil interest
in that region. Mineral and energy availability and needs often
shape foreign policy. The sanctions that the United States imposed
on South Africa in 1986, for example, did not include most of the
important minerals we had been importing and needed for our industrialized
society, such as platinum-group minerals. Many foreign policies
and treaties develop from the need to acquire and maintain adequate
mineral and energy resources.
Most people are unaware of the extent to which
geology affects their lives. For many people, the connection between
geology and such well-publicized problems as nonrenewable energy
and mineral resources, let alone waste disposal and pollution, is
simply too far removed or too complex to fully appreciate. But consider
for a moment just how dependent we are on geology in our daily routines.
Much electricity for appliances comes from burning
coal, oil, or natural gas, or from uranium consumed in nuclear-generating
plants. Geologists locate the coal, petroleum, and uranium. The
copper or other metal wires through which electricity travels are
manufactured from materials found as a result of mineral exploration.
The buildings we live and work in owe their very existence to geologic
resources. A few examples are the concrete foundation (concrete
is a mixture of clay, sand, or gravel, and limestone), the drywall
(made largely from the mineral gypsum), the windows (the mineral
quartz is the principal ingredient in the manufacture of glass),
and the metal or plastic plumbing fixtures inside the building (the
metals are from ore deposits, and the plastics are most likely manufactured
from petroleum distillates of crude oil).
Furthermore, when we go to work, our cars and public
transport are powered and lubricated by some type of petroleum by-product
and are constructed of metal alloys and plastics. And the roads
or rails we ride over are made of geologic materials, such as gravel,
asphalt, concrete, or steel. All these items are the result of processing
As individuals and societies, the standard of living
we enjoy directly depends on the consumption of geologic materials.
Therefore, we need to be aware of geology and of how our use and
misuse of geologic resources may affect the delicate balance of
nature and irrevocably alter our culture as well as our environment.
If we are to have a world in which poverty is not
widespread, then we must develop policies that encourage management
of our natural resources along with continuing economic development.
A growing, global population will mean increased demand for food,
water, and natural resources, particularly nonrenewable mineral
and energy resources. Geologists will play an important role in
locating the needed resources, as well as in protecting the environment
for future generations.
Part 2: From "Basin and Range"
by John McPhee
I used to sit in class and listen to the terms
come floating down the room like paper airplanes. Geology was called
a descriptive science, and with its pitted, outwash plains and drowned
rivers, its hanging tributaries and starved coastlines, it was nothing
if not descriptive. It was a fountain of metaphor - of isostatic
adjustments and degraded channels, of angular unconformities and
shifting divides, of rootless mountains and bitter lakes. Streams
eroded headward, digging from two sides into mountain or hill, avidly
struggling toward each other until the divide between them broke
down, and the two rivers that did the breaking now became confluent
(one yielding to the other, giving up its direction of flow and
going the opposite way) to become a single stream. Stream capture.
In the Sierra Nevada, the Yuba had captured the Bear. The Macho
member of a formation in New Mexico was derived in large part from
the solution and collapse of another formation. There was fatigued
rock and incompetent rock and inequigranular fabric in rock. If
you bent or folded rock, the inside of the curve was under great
tension, and somewhere in the middle was the surface of no strain.
Thrust fault, reverse fault, normal fault - the two sides were active
in every fault. The inclination of a slope on which boulders would
stay put was the angel of repose. There seemed, indeed, to be more
than a little of the humanities in this subject. Geologists communicated
in English; and they could name things in a manner that sent shivers
through the bones. They had roof pendants in their discordant batholiths,
mosaic conglomerates in desert pavement. There was ultrabasic, deep-ocean,
mottled green-and-black - or serpentine. There was the slip face
of the barchan dune.
In 1841, a paleontologist had decided that the
big creatures of the Mesozoic were "fearfully great lizards,"
and had therefore named them dinosaurs. There were festooned crossbeds
and limestone sinks, pillow lavas and petrified trees, incised meanders
and defeated streams. There were dike swarms and slickensides, explosion
pits, volcanic bombs. Pulsating glaciers. Hogbacks. Radiolarian
ooze. There was almost enough resonance in some terms to stir the
adolescent groin. The swelling up of mountains was described as
an orogeny. Ontogeny, phylogeny, orogeny - accent syllable two.
The Antler Orogeny, the Avalonian Orogeny, the Taconic, Acadian,
Alleghenian Orogenies. The Laramide Orogeny. The center of the United
States had had a dull geologic history - nothing much being accumulated,
nothing much being eroded away. It was just sitting there conservatively.
The East had once been radical - had been unstable, reformist, revolutionary,
in the Paleozoic pulses of three or four orogenies. Now, for the
last hundred and fifty million years, the East had been stable and
conservative. The far-out stuff was in the Far West of the country
- wild, weirdsma, a leather-jacket geology in mirrored shades, with
its welded tuffs and Franciscan melange (internally deformed, complex
beyond analysis), its strike-slip faults and falling buildings,
its boiling springs and fresh volcanics, its extensional disassembling
of the earth.
There was, to be sure, another side of the page
-full of geological language of the sort that would have attracted
Gilbert and Sullivan. Rock that stayed put was called autochthonous,
and if it had moved it was allochthonous. "Normal meant "at
right angles." "Normal" also meant a fault with a
depressed hanging wall. There was a Green River Basin in Wyoming
that was not to be confused with the Green River Basin in Wyoming.
One was topographical and was on Wyoming. The other was structural
and was under Wyoming. The Great Basin, which is centered in Utah
and Nevada, was not to be confused with the Basin and Range, which
is centered in Utah and Nevada. The Great Basin was topographical,
and extraordinary in the world as a vastness of land that had no
drainage to the sea. The Basin and Range was a realm of related
mountains that coincided with the Great Basin, spilling over slightly
to the north and considerably to the south. To anyone with a smoothly
functioning bifocal mind, there was no lack of clarity about Iowa
in the Pennsylvanian, Missouri in the Mississippian, Nevada in Nebraskan,
Indiana in Illinoian, Vermont in Kansan, Texas in Wisconsinan time.
Meteoric water, with study, turned out to be rain. It ran downhill
in consequent, subsequent, obsequent, resequent, and not a few insequent
As years went by, such verbal deposits would thicken.
Someone developed enough effrontery to call a piece of our earth
an epieugeosyncline. There were those who said interfluve when they
meant between two streams, and a perfectly good word like mesopotamian
would do. A cactolith, according to the American Geological Institute
Glossary of Geology and Related Sciences, was "quasi-horizontal
chonolith composed of anastomosing ductoliths, whose distal ends
curl like a harpolith, thin like a sphenolith, or bulge dscordantly
like an akmolityh or ethmolith." The same class of people who
called on rock serpentine called another jacupirangite. Clinoptilolite,
eclogite, migmatite, tincalconite, szaibleyite, pumpellyite. meyerhofferite.
The same class of people who called one rock paracelisian called
another despujolsite. Metakirchheimerite, phlogopite, katzenbuckelite,
mboziite, noselite, neighborite, samsonite, pigeonite, muskoxite,
pabstite, aenigmatite. Joesmithite.
With the X-ray diffractometer and the X-ray fluorescence
spectrometer, which came into general use in geology laboratories
in the late ninteen-fifties, and then with the electron probe (around
1970), geologists obtained ever closer examinations of the components
of rock. What they had long seen through magnifying lenses as specimens
held in the hand -or in thin slices under microscopes - did not
always register identically in the eyes of these machines. Andesite,
for example, had been given its name for being the predominant rock
of the high mountains of South America. According to the machines,
there is surprisingly little andesite in the Andes. The Sierra Nevada
is renowned throughout the world for its relatively young and absolutely
beautiful granite. There is precious little granite in the Sierra.
Yosemite Falls, Half Dome, El Capitan - for the most part the "granite"
of the Sierra is granodiorite.
It has always been difficult enough to hold in
the mind that a magma which hardens in the earth as granite will
- if it should flow out upon the earth - harden as rhyolite, that
what hardens within the earth as diorite will harden upon the earth
as andesite, that what hardens within the earth as gabbro will harden
upon the earth as basalt, the difference from pair to pair being
a matter of chemical composition and the differences within each
pair being a matter of texture and of crystalline form, with the
darker rock at the gabbro end and the lighter rock the granite.
All of that - not to mention such wee appendixes as the fact that
diabase is a special texture of gabbro - was difficult enough for
the layman to remember before the diffractometers and the spectrometers
and the electron probes came along to present their multiplex cavils.
What had previously been described as the granite of the world turned
out to be a large family of rock that included granodiorite, monzonite,
syenite, adamellite, trondhjemite, alaskite, and a modest amount
of true granite. A great deal of rhyolite, under scrutiny, became
dacite, rhyodacite, quartz latite. Andesite was found to contain
enough silica, potassium, sodium, and aluminum to be the fraternal
twin of granodiorite. These points are pretty fine. The home terms
still apply. The enthusiasm geologists show for adding new words
to their conversation is, if anything, exceeded by their affection
for the old. They are not about to drop granite. They say granodiorite
when they are in church and granite the rest of the week.
Picture credits: "Research" pictures
are from us. Mineral pictures are from "Simon and Schuster's
Guide To Rocks & Minerals," edited by Prinz et al., 1978.
Astronomical pictures are from NASA (http://antwrp.gsfc.nasa.gov/apod/).
Other pictures are from the USGS (http://www.usgs.gov/).