The Earth moves in mysterious ways. In some parts of the world, movement creates mountains, faults and earthquakes. However, in others, there aren’t any noted land deformations along areas where movement occurs.
Why is that? Geology Professor Sven Morgan has a hunch — but he’s looking to gather scientific evidence to prove it.
“Quartz is an abundant material in the Earth’s crust. In the lab, we’ve seen that if water gets into quartz grains, it weakens the rock. But we don’t have any evidence from natural examples,” said Morgan, who is campus’ Natural Sciences department chair. “If we can demonstrate this in a natural setting, it will affect how we study the Earth. It could also have implications on materials science, like, for example, how concrete is produced.”
Geologically speaking, the reason water is important is because it has major implications for how plate tectonics works.
For example, where the Indian and Asian tectonic plates meet to produce the Himalayas. “The Indian plate is strong and smashing into the Asian plate —but the Indian plate is not deforming. There are no mountains, faulting or earthquakes. The Asian plate is crumpled and weak and the collision produced the Himalayas and the Tibetan plateau (an area uplifted to an average elevation of 15,000 ft and is five times the size of France). We hypothesize that’s happening because water got into the interior grains of the Asian plate millions of years ago whereas the rocks making up the Indian plate are dry.”
Thanks to more than $500,000 in grant funding, Morgan is embarking on a three-year research project looking at how water gets into quartzites in a unique area in eastern California near the Nevada border.
Looking to prove the hypothesis, the research side of Morgan’s project will be supported by a team of three UM-Dearborn students, professional colleagues from Fayetteville State University and Central Michigan University, and a postdoctoral student.
He said the team will collect samples along a 5 km long traverse of quartzite (which is formed when quartz and sandstone are put under tectonic pressure) in California that exhibits both strong and weak behavior. Most of the quartzite seems to have behaved “strong” whereas one end seems to have behaved very weak. They will then examine the quartz grains in detail in the lab.
“Our idea is that the weak part of the quartzite got heated up by a nearby magma body that intruded 180 million years ago. When that happened, the grain boundaries migrated and allowed the water to get into the interior of grains and cause the weakening,” he said. “The implications are pretty grand because we believe that sub-microscopic amounts of water in minerals may be the factor on why the mostly dry Indian plate is stronger than the ‘wet’ Asian plate.”
Morgan said they’ll use various micro-analytical techniques — like Secondary Ion Mass Spectrometry and a Scanning Electron Microscope — to measure if and how water gets into quartz and significantly weakens rocks.
Part of the NSF grant is also for outreach in science education and he’s working with Biological Sciences faculty member Patricia Hartshorn, who specializes in science education, to include teachers and students from Cesar Chavez Academy High School in Detroit.
“We’re designing a geology-based dual-enrollment class on the tectonics of the western U.S. and how water plays a big part in shaping the landscape. I’ll go into the classroom and teach along with their teachers. Then, at the end of the class, 10 students and three teachers will have the opportunity to come out west to California,” said Morgan, noting that the National Sciences Foundation grant he secured makes the experience free for participants. “I have a passion for geology because I had a teacher who inspired me. The scenery in eastern California is also very beautiful. Dry desert ranges are to the east and Sierra Nevada Mountains are to the west. There is a lot of geological diversity there too: earthquakes, trilobites, volcanoes and glaciers. If there is a place to spark a love for geology, this is definitely it.”
With the data he gathers, he hopes to prove a longtime scientific speculation and inspire a few minds along the way.
“Geologists are storytellers who use land formations and other clues to share what monumentally occurred in the past. We can’t go down and sample the center of the Earth, but there are still ways to find out why things came to be as we see them today,” he said. “And, in discovering how the Earth works and affects everything we do, I hope that students will be inspired to continue to fill in future chapters of the story.”
Article by Sarah Tuxbury.