Transcript Slide 1

Death Valley
Take a stroll through one of the lowest
pieces of land in the Western
Hemisphere (282 feet below sea level),
a place that, strangely enough, also
happens to be adjacent to the highest
point of land in the lower 48 states of
the U.S., the 14,494 ft. mountain peak of
Mt. Whitney.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
Zabriskie Point, in midwinter. The soft sediments at Zabriskie Point were deposited in an old lake,
and are being eroded into the beautiful features seen here. The snow-covered peaks in the
background tower two miles above the valley floor. (Photo by Penn State graduate, now University
of New Mexico professor, Peter Fawcett.)
Unit 2 – Making Mountains – Death Valley
Geosc. 10
Badwater in midwinter. Peter Fawcett, noted Penn State alumnus and
University of New Mexico professor, at 282 feet below sea level. The little bit of
water from a midwinter storm will evaporate quickly.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
Salt flats in midwinter, Death Valley. Water, such as seen in the previous
picture, carries dissolved minerals (ask a plumber who has tried to remove a
faucet in a house with hard water if you don't believe this!). When the water
evaporates, the salt is left. Photo by Peter Fawcett.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
20-mule team. The salts deposited in Death Valley included valuable materials such as borax,
containing boron dissolved from volcanic and other rocks around the valley. The salts were mined,
and the borax hauled out by 20-mule teams. This is a picture from a reenactment of the mule
teams, years after the mining ceased. Photo by Ed Derobertis of the National Park Service.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
Probably the most familiar of the many uses of borax is in laundry detergents. Before he
was president of the United States, actor Ronald Reagan advertised a laundry detergent
containing borax, as shown in this photo from the National Park Service archives.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
Another salt flat is shown here. Behind the salt flat, at the foot of the mountains, is an alluvial fan, a pile of gravel
brought down into the valley from the mountains by streams that run for a short while after rainstorms. The vertical
distance between the lowest point (end of the pink arrow) and highest point (end of the yellow arrow) on the fan is
greater than the vertical distance from Spring Creek to the top of Mt. Nittany near Penn State¹s University Park
Campus--the fan is taller than most eastern mountains! The scale of things in Death Valley is immense, and very
difficult to comprehend. Photo by Peter Fawcett
Unit 2 – Making Mountains – Death Valley
Geosc. 10
Again, putting Penn State’s Mt. Nittany, or many other eastern mountains, into this picture wouldn’t
change it much - they would reach only part of the way from the salt flat at the bottom (shown by
the orange arrow) up the fan (the top of the fan is shown by the yellow arrow), far shorter than the
peaks in the picture.
Photo by Peter Fawcett
Unit 2 – Making Mountains – Death Valley
Geosc. 10
During the ice age, more rain fell in Death Valley because storm tracks had moved, and less water evaporated
because temperatures were lower than today. A huge lake filled Death Valley then. In this rather fuzzy slide
downloaded from the USGS-National Park Service web site, the horizontal lines (the ends of one are shown by
the blue arrows) are old beaches from that lake.
The photo of Shoreline Butte is by Marli Miller.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
Some of the gravels washed into the valley by streams are shown
in this photo by Peter Fawcett.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
Deserts are not dominated by dunes in many places, but dunes do occur. The streams flowing into
Death Valley carry salts, big rocks, but also sand. If the sand is piled by wind, beautiful forms may result,
such as these.
Photo by Paul Stone, United States Geologic Survey
Unit 2 – Making Mountains – Death Valley
Geosc. 10
The enigmatic Devil's Racetrack. The stones rather clearly have moved across the surface of the salt flat.
Strong winds during wet times are probably involved. Perhaps a thin water layer forms in a winter storm,
freezes on top on a cold night, and then the wind drags the ice carrying the rocks. Photo by Marli Miller,
from the Death Valley National Park web site.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
Death Valley was dropped along faults (or the mountains were raised, or both). The Hanaupah
Fault (between the blue arrows) cuts the toe of an alluvial fan coming down from Telescope
Peak, shown in this photo by Marli Miller from the Death Valley National Park web site.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
UP
DOWN
A closer view of The Hanaupah Fault (between the blue arrows) as seen in the previous
picture, with labels showing which side of the fault was raised (“UP”) and lowered (“DOWN”).
Photo by Marli Miller, from the Death Valley National Park web site.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
http://www2.nature.nps.gov/GEOLOGY/usgsn
ps/deva/Ubehebe_field19.jpg Peter Sanchez
http://marsweb.jpl.nasa.gov/missions/behind/images/ubehebe_crater.jpg
http://www2.nature.nps.gov/GEOLOGY/u
sgsnps/deva/LUbe.jpg Marli Miller
Hot rocks occur at shallow depth under Death Valley, and break through occasionally in volcanoes,
usually coming up along faults; farther to the south, stronger volcanism has made the sea floor of
the Gulf of California. In Death Valley, the eruptions are not especially strong, but they have made
craters, such as those in the Ubehebe volcanic field, shown in these photos.
Unit 2 – Making Mountains – Death Valley
Geosc. 10
http://wrgis.wr.usgs.gov/parks/deva/ftcin2.html
Photo by Tom Bean, National Park Service
Sometimes, volcanoes make small cinder cones, composed of little rocks and hardened blobs of
lava thrown through the air. And, sometimes faults move rocks horizontally, as shown here (upper
left without lines, and lower right with fault shown by dashed line and motion by arrows) for Split
Cinder Cone in Death Valley. Most of the faulting in Death Valley is related to the dropping of the
Valley and raising of the mountains, but horizontal motions such as this do occur occasionally.
Unit 2 – Making Mountains – Death Valley
Geosc. 10