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| Gower
Gulch, where it emerges from the Black Mountains
onto the floor of Death Valley. Incision of the
fan surface has taken place entirely since 1941,
as a result of the diversion of the drainage of
Furnace Creek Wash into Gower Gulch by the staff
of what was then Death Valley National Monument.
Photo by Nicholas Christie-Blick. |
Death Valley—the name conjures
images of a searing, arid wasteland, and its main claim
to fame is that it contains the lowest point of land
in the Western hemisphere, at 282 feet below sea level.
But metaphorically speaking, Death Valley’s unusual
altitude is just the tip of its iceberg of geological
wonders. With its steep, faulted margins, upturned ancient
sea beds, and modern-day volcanic craters, Death Valley
offers a front-row seat to a panorama of Earth’s
activity that goes back 1.7 billion years and continues
today.
There are in fact
twenty seats, to be exact. That is how many slots are
open to first- and second-year Columbia University students
for Dr. Nicholas Christie-Blick’s annual geology
field trip to Death Valley. To Dr. Christie-Blick, professor
of geology and associate chair of Columbia University’s
Department of Earth and Environmental Sciences, there
is no better way to learn about geology than getting
up close and personal with the world-class Death Valley
outcrops that best define such terms as extrusive igneous
rocks, extensional faults, and fossiliferous carbonate
sediments.
Designed for students
with little or no background in the earth and environmental
sciences, the week-long excursion emphasizes a heuristic
rather than show-and-tell approach to learning. “We
focus on a small number of contrasting geological vignettes,
both modern and ancient, and the students get to develop
interpretations of what they see from first principles…The
details of Death Valley, as interesting and controversial
as they are, are for us a vehicle by which students
come to see how the scientific method works in a geological
context,” explains Prof. Christie-Blick.
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| This
image shows everyone in the Spring ’03 group with
the exception of one student and TA Gad Soffer,
who is presumably taking the picture. We're in the
sand dunes in Death Valley. Photo by Hasan Merali.
|
Students prepare
for the field trip by attending several discussion sessions
that provide an overview of Death Valley’s geological
phenomena. Reading assignments include materials at
several levels. Most accessible are those aimed at the
general public: the Death Valley National Park website,
and chapters from Geology Underfoot in Death Valley
and Owens Valley by Sharp and Glazner. Other assignments
are drawn from Earth, by Press and Siever,
and articles from the mainstream geological literature.
In the months leading
up to the excursion, Prof. Christie-Blick also connects
the geology to be examined with world events—this
year, he discussed the huge earthquake of November 3,
2002, on the Denali fault in Alaska, and the geology
of Iraq. “The Denali fault is a strike-slip fault,
one that allows adjacent crustal blocks to move sideways.
That is also the character of the Northern Death Valley
fault zone, which is still active and which we explore
during the excursion.
"Iraq lies along
the southwestern margin of a mountain belt that is being
squeezed horizontally. The faults and folds of the Spring
Mountains, which we examine on the first afternoon of
the trip, were produced by the same process some 100
million years ago.”
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| Wilson
Cliffs, Spring Mountains, Nevada. Eolian sandstone
approximately 200 million years old (cliffs) overthrust
by 500 million-year-old marine carbonate rocks
(top left). Photo by Nicholas Christie-Blick. |
Although introductory
in nature, the course web site warns that the field
trip isn’t “Earth science for poets”
or “geotourism.” Students have to come prepared
to do real geology. Prof. Christie-Blick emphasizes
the scientific practice of making observations and taking
notes in a field journal throughout the week, whether
the focus of study is at the scale of a mountain side
or a speck of sand as seen with a hand lens (magnifying
glass). Prof. Christie-Blick and his teaching assistant,
Gad Soffer, bring along an array of other tools for
specific outcrops: a geological hammer, shovel, whisk
broom, Brunton compass, and hydrochloric acid that is
needed to test carbonate rock samples. Prof. Christie-Blick
warns students to look carefully before they sit down,
and to watch where they put their hands when scrambling
over rocks because Death Valley is home to both rattlesnakes
and scorpions. Far more likely dangers, however, are
dehydration and sunburn. Prof. Christie-Blick takes
care that students bring plenty of sunscreen and carry
ample water.
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| Spring
Mountains, Nevada. Eolian sandstone approximately
200 million years old (red rocks) overthrust by
and folded to a near-vertical orientation beneath
500 million-year-old marine carbonate rocks (grey).
Photo by Nicholas Christie-Blick. |
The days are long,
with students heading off at 7:30 or 8:00am and returning
at 6:00pm, but “exhilarating,” as one student
put it. The daily itinerary includes visits to two key
localities and short stops at other notable places.
Few of the stops are selected from those most commonly
seen by visitors—the best geology is often found
off the beaten track—but the scenery is dramatic
from virtually any vantage point. After a brief introduction
of each site by Prof. Christie-Blick, the students work
alone or in small groups to explore, make observations,
collect data, and develop hypotheses about what they
are seeing. Prof. Christie-Blick then leads discussions
during which students are able to debate their ideas.
Prof. Christie-Blick
finds it hard to come up with a list of the best geological
examples from the field trip because Death Valley contains
so many world-class examples and each is unique and
interesting in its own way. That being said, students
seem to find the following sites most thought-provoking:
Ubehebe Crater, more than 770 feet deep and half a mile
wide, is the result of volcanic activity that took place
less than 3,000 years ago, when magma worked its way
through a fault at the base of Tin Mountain and ran
into rain-soaked bedrock and alluvial fan sediments,
causing repeated steam explosions.
Throughout northern and central Death Valley, alluvial
fans, which have developed only in the last few thousand
years since the disappearance of the 600-foot-deep Lake
Manly, are cut and offset by active faults. At Gower
Gulch, the students examine these geological phenomena
and the unintended environmental consequences of the
diversion of floodwater since 1941 from the much larger
Furnace Creek Wash.
Of the ancient geological
examples examined, among the most impressive are hill-sized
mounds, or stromatolites, in the Noonday Dolomite, built
by primitive microbial organisms some 700 million years
ago, before the advent of modern metazoan organisms.
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| Ubehebe
crater. Photo by Nicholas Christie-Blick. |
In the Spring Mountains,
marine carbonate rocks more than 500 million years old
have been pushed up and over the top of much younger
(200 million years), wind-blown sandstones along huge
faults. This activity has left the oldest rocks at the
highest elevations and the youngest cropping out near
the foot of the mountains, where some of the youngest
are also upside down. Students developed reasoning for
determining the direction in which the sandstones become
younger as well as the setting in which they originally
accumulated.
Experiencing the
life of a field scientist does not end at sunset. Spring
break coincides with ideal camping weather in Death
Valley. So students “rough it” for two nights,
sleeping out in the open under the stars at Furnace
Creek. With an annual rainfall of less than two inches,
tents are usually considered optional. However, they
were quite welcome this year when a freak rainstorm
started “dumping buckets of water” on the
students in the middle of the night. Students also spend
five evenings in bunkrooms at the Shoshone Education
and Research Center (SHEAR). Small teams take turns
preparing the evening meal for the group, including
clean up. To help conserve water, many students enjoy
bathing in the segregated hot springs at Tecopa, 8 miles
to the south, or taking a dip in the naturally heated
spring-water pool at the Furnace Creek Ranch.
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| Spring
Mountains, Nevada, where marine carbonate rocks
more than 500 million years old (grey) in horizontal
thrust fault contact with 200 million-year-old
wind-blown sandstones beneath (red). Photo by
Nicholas Christie-Blick. |
Students found the
entire experience incredibly rewarding. Andrew Tolve,
a second-year Columbia student with a triple concentration
in English, History, and Earth Science, said, “Being
in an environment where geology was so tangible was
unbelievable. Everything was so exposed— twisting
fault lines, salt pans, alluvial fans. The course explained
geology in a way that no textbook could, it brought
it all to life.” When asked what he most appreciated
about the course, Mr. Tolve said, “It offered
a six-day glimpse into how scientists operate, the mindset
in which they approach problems. I realized that geology
rests upon simple observations that anyone can make,
and from this basis of evidence, scientists can form
more complex theories. But the evidence is out there
for anyone to find and that’s why the field is
such a dynamic one.”
Pearl Flath, a second-year
Applied Mathematics Columbia student, said “I
really loved the trip, it was awesome. I’d do
it again if I could.” She described her favorite
day, when Prof. Christie-Blick took the students to
a “gigantic lump, this mud mound with lots of
layers. At first we thought it was a volcano plug, but
then we examined it more closely with our hand lenses
and saw all of these little sea critters—we realized
we were standing on a fossilized coral reef.”
Ms. Flath “really liked the process of figuring
out on our own what formations were and how they were
formed.” She said that by midway through the trip,
students were having lively scientific debates about
cause and effect.
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| Central
Death Valley, from Dante's View. Telescope Peak
(11,049 ft) rises above Badwater (bottom of image,
282 ft below sea level). Photo by Nicholas Christie-Blick. |
When asked if the
experience changed her ideas regarding a future career,
Ms. Flath replied, “The course opened up a whole
new area of earth science to me. I never really thought
about the field of geology before, never thought geologists
had such an exciting time. The nice thing about applied
math is that it can be applied to nearly any scientific
endeavor, including geology. Maybe I’ll be modeling
seismic activity some day.”
Some students were
just happy to be away from their hectic city university
student lifestyle. “Something about being out
in the wilderness, away from the pressures of everyday
life, no cell phones, no shopping, it was so calming.
Despite hiking all day, the trip was really laid back
and relaxing,” said Shari Keller, a second-year
Psychology major at Columbia. She also enjoyed “the
investigative process…it was so cool to go out
there and try to figure the geology out, like putting
together the pieces of a jigsaw puzzle. It was amazing
to learn how much goes into science, you have to think
like a detective!”
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| Spring
’03 group at China Ranch. Photo by Nicholas Christie-Blick. |
All of the students
mentioned how Prof. Christie-Blick’s enthusiasm
for his subject was contagious—“He really
encouraged us to ask questions,” said Mr. Tolve.
The students appreciated the patience he and his teaching
assistants exhibited, especially for answering the ubiquitous
“What’s this rock? Ok, how about this one?”
Ms. Flath said, “Nick’s a great teacher,
he never tires of explaining things.” “He
really knew how to make us think in a way that was actually
fun,” said Ms. Keller.
Prof. Christie-Blick
doesn’t know how many students have changed their
intended majors to Earth Science as a result of the
field trip. “I want to give all of them an appreciation
for geology in the field, but, more importantly, I want
to challenge them to think through things for themselves.
Some may not head into the sciences down the road, but
they will have had a great Columbia experience that
hopefully leaves them with a deeper appreciation for
the Earth.” Of course, he would be delighted if
a fraction of the students signed up for majors or concentrations
in his department.
For those students
interested in learning more about the geology field
trip (Earth and Environmental Science course V1010y,
worth 2 credits), please visit Prof. Christie-Blick’s
course web site at http://www.ldeo.columbia.edu/dees/V1010/.
He will update it shortly with application information
and other details for the Spring Break 2004 Geological
Excursion.
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