The Great Upheaval Dome Controversy EarthCache
The Great Upheaval Dome Controversy
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In Canyonlands NP, Islands in the sky section. It can be viewed
from whale rock or upheaval dome trail, the cache location. Trail
is between .8 mile and 1.8 miles long and the elevation change is
200'-250', depending on how far you want to go.
NOTICE: ALL LOG ENTRIES NOT MEETING
THE LOGGING REQUIREMENTS WILL BE DELETED! See logging reqirements
at end of description. This feature is a geological enigma that has
split scientists as to its origin. It looks like a meteor crator
but with an eroded aticline (dome) in the middle of the crator.
Uphieval dome was long thought to be a very large example of an
eroded salt dome, formed from overlying rock pressuring the
underlying salt layer wich in turn would heave up through a week
section in the rock layer. This long accepted theory was challenged
in 1993, when Eugene Shoemaker (co-discoverer of Shoemaker-Levy
Commet) and Ken Herkenhof introduced evedence supporting the then
unpopular meteor crater theory. Basically this theory explains the
concentric rings surrounding the dome as being a direct result of
extraterrestrial impact, much like the rings on the surface of a
body of water when a rock is thrown into it. They discovered
shattercones (conical shaped rocks with fractures radiating out
from a central point) and shocked quartz (normal quartz that has
been highly fractured) which is direct evidence of an impact.
Further supporting evidence came two years later when John Louie of
the University of Nevada/Reno conducted seismographic tests of the
area and concluded there was no salt layer under upheaval dome
(meteorite.com/impact/upheaval.htm). Acording to the National Parks
Service, rocks found on the surface of the crator were once a mile
below the serface and are not found anywhere else in the area. THE
COMPEATING THEORIES Salt Dome theory
(nps.gov/cany/naturescience/upheavaldome.htm) A thick layer of
salt, formed by the evaporation of ancient landlocked seas,
underlies much of southeastern Utah and Canyonlands National Park.
When under pressure from thousands of feet of overlying rock, the
salt can flow plastically, like ice moving at the bottom of a
glacier. In addition, salt is less dense than sandstone. As a
result, over millions of years salt can flow up through rock layers
as a "salt bubble", rising to the surface and creating salt domes
that deform the surrounding rock. When geologists first suggested
that Upheaval Dome was the result of a salt dome, they believed the
land form resulted from erosion of the rock layers above the dome
itself. Recent research suggests that a salt bubble as well as the
overlying rock have been entirely removed by erosion and the
present surface of Upheaval Dome is the pinched off stem below the
missing bubble. If true, Upheaval Dome would earn the distinction
of being the most deeply eroded salt structure on earth. Impact
crator theory (from nps.gov/cany/naturescience/upheavaldome.htm)
When meteorites collide with the earth, they leave impact craters
like the well-known one in Arizona. Some geologists estimate that
roughly 60 million years ago, a meteorite with a diameter of
approximately one-third of a mile hit at what is now the Upheaval
Dome. The impact created a large explosion, sending dust and debris
high into the atmosphere. The impact initially created an unstable
crater that partially collapsed. As the area around Upheaval Dome
reached an equilibrium, the rocks underground heaved upward to fill
the void left by the impact. Erosion since the impact has washed
away any meteorite debris, and now provides a glimpse into the
interior of the impact crater, exposing rock layers once buried
thousands of feet underground. Thanks to Meteorite.com and nps.gov,
and to the staff at Canyonlands National Park for permission in
placing this Earthcache! To claim this cache, you MUST post a
picture of your GPSr at any overlook location, and send me a
message with the answer to the following question:
Stratigraphically, name two formations that can be seen
here(specifically, what sedimentary layers)? Congrats to Redburne
on FTF!
Additional Hints
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