Sam Coleman: Traveling to Mars and Back in Time to Learn about Earthquake Faults

Sam Coleman
2011 Geology
Hometown: Santa Ana, CA
Career Goal: Professor of Geology, or Geologist with the US Geological Survey
As a recipient of a NASA Space Grant, NAU undergraduate Sam Coleman has been on Mars, or as close as humans have gotten to actually being on the red planet. Sam has been analyzing highly detailed satellite images of Mars at the US Geological Survey, looking for evidence of winds. One day, while studying the surface of Mars, Sam "stumbled into a crater in a dune field. It was a pretty cool discovery, because no one had previously documented any craters on the dunes of Mars." If enough such craters are found, they can be used to estimate the age of the dune.
The excitement of this discovery has led Sam to pursue other research opportunities. As luck would have it, he heard about two interesting research projects supervised by Dr. Paul Umhoefer, Professor of Geology at NAU.
Starting this fall, Sam will be working with Dr. Umhoefer to examine the interaction between two fault systems in the Lake Mead area. The two faults have been extending, like cracks in a car windshield, for around 17 million years. Similar to the infamous San Andreas Fault in California, these faults are strike slip faults, but they are moving in opposite directions and are meeting at almost a right angle. Though both systems have been studied individually, the nature of their interactions with each other is still unclear. Studying these interacting systems in the exposed landscape of the Lake Mead area, where they can be easily seen on the surface, may allow researchers to predict the behavior of similar systems in other locations.

Another project Sam will carry out under Dr. Umhoefer's mentorship involves examining ancient layers of ash in the Horse Springs Formation. Cliff faces in the Horse Springs Formation reveal layers of ash among strata of other sediment types. The interval between each ash layer represents a time period of 100,000 to 200,000 years, and correlates fairly well with wobbles in the Earth's orbit called Milenkovich Cycles, which are associated with historic climate change. Between the layers of ash on the cliff faces, Sam hopes to identify features such as sand dunes or muddy lake bottoms that will provide clues about climate during a particular time period. This information may help researchers better understand-and perhaps even predict-future climate changes.
"Research is exciting because it gives you the opportunity to discover something new and make a difference in the world. Even small discoveries are important because every advance in knowledge deepens our understanding of the world."
Sam advises incoming NAU freshman to get involved in research as soon as possible. Undergraduate research experience may help students get jobs after graduation, and is important for those who are planning to go to graduate school. "Learn how to manage your time, because good time management is key to college success."
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