Corvi Wallace and Jennifer Lawson like it hot. That came in handy in their Winter Quarter geology class.
Sure, it was cold and rainy in Seattle. But for two glorious weeks, Wallace, Lawson, and 14 fellow students traipsed around in the heat of Oman, a small country on the eastern margin of the Arabian Peninsula. The trip was the field component of "The Origin of Oceanic Crust," a UW course offered jointly by the Departments of Geological Sciences and Oceanography.
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| During their trip to Oman, UW students sampled the layered gabbro, normally submerged deep under the Earth's oceans. |
Why travel halfway around the world for a field trip? When it comes to studying oceanic crust, the site is unparalleled. "Although most of our planet is made up of oceanic crust, it's hard to see," explains Bruce Nelson, professor of geological sciences. "Most of it is submerged deep under the oceans. But in a few places, geologic processes have caused a piece of oceanic crust and the mantle beneath it to break off and rise up onto the land. Oman is by far the best example on the planet of exposed oceanic crust."
In Oman, the exposed crust extends for more than 400 miles. The UW group--eight geology students, eight oceanography students, and four professors--covered the distance in white Land Cruisers, stopping frequently to examine portions of the crust. They were joined by a group from the University of Oregon and two French scientists who are experts on the region.
"There's one main road up the coast," Lawson recalls. "We'd drive on the road in a caravan and then just turn off onto unmarked dirt roads, which we'd follow for hours. The French guides had figured out where to take us and what kinds of rocks to see. We'd arrive at an outcrop [of oceanic crust] in the middle of nowhere and we all had to wonder, 'How did anyone find this in the first place?'"
The exposed oceanic crust in Oman is tilted in such a way that visitors, if they travel far enough, can view all of its layers. The top layer consists of pillow lavas--lavas that form underwater--and deep sea sediments. Next come "feeder channels"--places where magma has broken through the crust to the ocean floor--followed by gabbro, a type of rock that makes up most of the oceanic crust. At the bottom is the earth's mantle.
The scale of the outcrops was impressive even to those familiar with oceanic crust. "I had a pretty good idea of what I was going to see before we got there, but everything was on a much larger scale than I'd previously seen," recalls Geology Professor Stu McCallum, who co-taught the course with Nelson and Professors William Wilcock and Debbie Kelley from the Department of Oceanography. "I'd seen outcrops of pillow lava in the Olympic Mountains here at home, but in Oman the outcrops go on for hundreds of kilometers. What that gives you is an ability to really test hypotheses for the origins of the oceanic crust."
As it turns out, there are still plenty of questions about the crust's origins. And the UW students were expected to tackle some of them in Oman.
"During the first half of the course, we covered what is known about oceanic crust so that students would be prepared to make observations and do research when they arrived in Oman," says Nelson. "Then we had them develop research proposals. By the time we left for Oman, the students had very specific goals and projects."
"To get to go on a trip like this really advances a student's understanding of what's involved in doing research...The whole experience was just amazing."
Wallace, an undergraduate, and Lawson, a graduate student, teamed up to study gabbro. One puzzling characteristic of gabbro is that it has layers similar to those seen in sedimentary rock although it crystallized from magma. There is much debate among geologists about the cause of this layering. The students took on this question, mapping portions of the gabbro and collecting oriented samples for further study in a UW laboratory.
"Some people return from trips with souvenirs; we all came back with boxes of rocks," jokes Wallace. "Even the backpack I carried on the plane was filled with 20 pounds of rocks. This really confused the customs people. As you might imagine, the airport was chaos."
What will become of all those rocks? "We will make thin sections from the gabbros," says Lawson. "Then we can study individual mineral grains under a microscope to see if they are distorted or aligned in any certain direction. That may provide answers." Lawson and Wallace plan to continue their research this summer.
Nelson believes that the many unanswered questions about oceanic crust--and the opportunity for students to explore them--made the trip particularly exciting. "This is real science," he says. "These are questions the scientific community is truly interested in understanding. The students can make a real contribution."
That the trip happened at all is a testament to the tenacity--and connections--of the faculty involved. Wilcock, who had conducted a small research project in Oman, used his connections with Omani government officials and researchers to gain permission for the visit. Then the faculty tapped various sources for funding, including the Geological Sciences and Oceanography Departments, the College of Arts and Sciences, and the Office of Undergraduate Education. Participating students were required to contribute $500.
"The financial support we got was amazing," says Lawson. "I think that everybody realizes this was a one-of-a-kind experience." Adds Wallace, "To get to go on a trip like this really advances a student's understanding of what's involved in doing research--the difficulties, the excitement...all of it. The whole experience was just amazing. To be in a research institution, with the connections that brings, made all the difference."
For more information, visit the Oman Field Trip Web site at http://quayle.ocean.washington.edu/oman/index.html.