Among the greatest of the park’s many attractions is the solitude one
can savor in the midst of magnificent scenery. Only a short walk
separates us from the highway, torrents of cars, noise, and tension.
Away from these, everything seems restful.
Quiescent it may seem, yet the landscape is not static but dynamic. This
is one of the many exciting ideas that geology has contributed to
society. The concept of the “everlasting hills” is a myth. All the
features around us are actually rather short-lived in terms of geologic
time. The discerning eye detects again and again the restlessness of the
land. We have discussed many bits of evidence that show how the
landscape and the earth’s crust beneath it are constantly being carved,
pushed up, dropped down, folded, tilted, and faulted.
The Teton landscape is a battleground, the scene of a continuing
unresolved struggle between the forces that deform the earth’s crust and
raise the mountains and the slow processes of erosion that strive to
level the uplands, fill the hollows, and reduce the landscape to an
ultimate featureless plain. The remainder of this booklet is devoted to
tracing the seesaw conflict between these inexorable antagonists through
more than 2.5 billion years as they shaped the present landscape—and the
battle still goes on.
Evidence of the struggle is all around us. Even though to some observers
it may detract from the restfulness of the scene, perhaps it conveys to
all of us a new appreciation of the tremendous dynamic forces
responsible for the magnificence of the Teton Range.
The battle is indicated by the small faults that displace both the land
surface and young deposits at the east base of Mount Teewinot, Rockchuck
Peak (fig. 15), and other places along the foot of the Tetons.
Jackson Hole continues to drop and tilt. The gravel-covered surfaces
that originally sloped southward are now tilted westward toward the
mountains. The Snake River, although the major stream, is not in the
lowest part of Jackson Hole; Fish Creek, a lesser tributary near the
town of Wilson, is 15 feet lower. For 10 miles this creek flows
southward parallel to the Snake River but with a gentler gradient, thus
permitting the two streams to join near the south end of Jackson Hole.
As tilting continues, the Snake River west of Jackson tries to move
westward but is prevented from doing so by long flood-control levees
built south of the park.
Recent faults also break the valley floor between the Gros Ventre River
and the town of Jackson.
The ever-changing piles of rock debris that mantle the slopes adjacent
to the higher peaks, the creeping advance of rock glaciers, the
devastating snow avalanches, and the thundering rockfalls are specific
reminders that the land surface is restless. Jackson Hole contains more
landslides and rock mudflows than almost any other part of the Rocky
Mountain region. They constantly plague road builders (fig. 17) and add
to the cost of other types of construction.
All of these examples of the relentless battle between constructive and
destructive processes modifying the Teton landscape are but minor
skirmishes. The bending and breaking of rocks at the surface are small
reflections of enormous stresses and strains deep within the earth where
the major conflict is being waged. It is revealed every now and then by
a convulsion such as the 1959 earthquake in and west of Yellowstone
Park. Events of this type release much more energy than all the nuclear
devices thus far exploded by man.
[Illustration: Figure 17. _Slide blocking main highway in northern
part of Grand Teton National Park. National Park Service photo by
Eliot Davis, May 1952._]