Once an Ocean, Now One of the Driest, Most Desolate Places on Earth
Vassar freshman Aaron Jones probably wasn’t the first visitor to Death Valley to observe that it looks a lot like the surface of Mars. But the future earth science major says if he hadn’t seen it for himself, he couldn’t have grasped the power of wind erosion and compared the resulting rock formations to those on the distant planet.
Jones was one of nine students in earth science and geography professor Jill Schneiderman’s class on sedimentary rocks and stratigraphy at Death Valley and the Mojave Desert during Spring Break. Before the trip, each student chose a site that had particular geological significance. The students did some initial research on their sites at the start of the semester, then gave oral presentations and gathered more information when they got there. They prepared posters on their expanded research at the end of the semester.
Jones, the only freshman in the class, says he had some anxiety about completing the course successfully when he first enrolled. “But going to Death Valley and seeing it for myself made the whole concept of sedimentation and erosion easier for me to understand,” he says.
In his presentation on ventifacts—rocks that are eroded by sand particles blown by the wind—Jones explained how studying their shapes enables scientists to determine wind patterns of the region over a long period of time. He noted the same phenomena are found on Mars. “The winds are stronger on Mars so the effects are greater, but it’s really quite similar to what you see at Death Valley,” Jones says.
Schneiderman says she had taken a class to Death Valley when she taught earth science at the University of California at Pomona nearly 25 years ago and was glad to be able to return with a class from Vassar. The land that comprises Death Valley was once part of an ocean—and at a different point in history part of an inland sea—and now one of the driest and most desolate places on earth. Because it has undergone so many transformations, its rocks and dry streambeds contain an abundance of information about the earth’s natural history.
“There’s a saying among geologists that you go where the rocks are—there’s no substitute for being there,” Schneiderman says. “When you’re there you can study the rocks in a way that can’t be done in a classroom or a lab.”
Marlena Crowell ’14 studied salt deposits in Badwater Basin, at 282 feet below sea level the lowest point in North America. Crowell says that in the field she collected a small sample from the valley floor that she believed to be mostly halite (salt). She brought the sample back to Vassar to analyze its composition, Using X-ray fluorescence and X-ray diffraction techniques, Crowell detected small bits of bassanite, gypsum and quartz along with the halite, key clues to determining its history and origin. “Exploring Death Valley showed me first-hand how important it is to go to the site for your research, and that’s one of the things that appeals to me about earth science,” Crowell says.
Kathleen Ewen '15 says her research enabled her to learn about the history of the earth not only near Death Valley but in other parts of the earth as well. She studied volcanic sediments, including volcanic ash from as far away as Yellowstone. “What we find here helps explain eruptions in Chile or at Yellowstone,” Ewen says.
The trip was made possible thanks to a grant for earth science field trips from an alumna, Joan Rockwell '72, who majored in geology and took a trip to Yellowstone National Park during her junior year. Schneiderman says the funds enable students to study the earth in a much more meaningful way.
“In geology, field trips aren’t optional,” she says. “The scale of the earth in terms of both size and time is so vast that there’s no other way to learn but to go see it. I thank Joan Rockwell for providing this experience to our students.”
Schneiderman says it’s part of her job to cultivate in her students “a sense of awe about the earth,” and taking them to places like Death Valley is one way to do so. “We live at a time when we’re witnessing the destruction of our environment, and it’s important to spur students to address these issues,” she says. “I want to show them the grandeur of the earth, something that nourishes their spirit. That’s one of my responsibilities as a science teacher.”
Posted Wednesday, May 15, 2013