UC Researchers Go Rafting for Rocks

After navigating the two-person inflatable raft successfully through a rough rapid, Professor Eva Enkelmann and Ph.D. candidate Jeanette Arkle managed to dock alongside a steep canyon wall. It was the only mode of transportation they could use to document land formations and collect a rock sample to bring back to the University of Cincinnati labs.

Arkle yelled to Enkelmann above the roaring whitewater, "I'm livin' the dream!"

The UC Geology Department’s Enkelmann coordinated and led the reconnaissance trip to Canada’s Mackenzie Mountains this summer to study the range. Some scientists have hypothesized that the Mackenzie Mountains may be related to the formation of the St. Elias Range, the high mountain range located in southeast Alaska. However, before Enkelmann’s trip, there was not a lot of research or rock samples to support this idea.

“When we set off on this trip we had the goal of collecting rock samples for later analysis,” Enkelmann said, “which will allow us to gain a better understanding of how the mountain range was built, or more specifically, the recent reactivation of the mountain building processes.”

The team’s biggest logistical challenge for the trip was accessing the remote interior of the mountain range for enough time to conduct their research. To overcome this obstacle, the team took advantage of a major river that cuts through the heart of the mountain range and used river rafts as not only their mode of transportation, but also as their base-camp.

A National Geographic Society grant assisted Enkelmann and her team by covering the cost of transportation to their remote destination. The team flew into the small town of Norman Wells in the Northwest Territory before they traveled to a mountain lake by floatplane. From there the team spent two days transporting their equipment to a river where they began traveling through the mountain range by raft boats.

Enkelmann and her team used the river rafts to travel 180 miles down the river that traverses the mountain range, allowing the team to stop and gather samples more frequently than if they had flown over the area by helicopter. Over the course of the two-week expedition the team gathered about 600 pounds of rock samples. The team collected different types of rocks that are 400 to 600 million years old and once formed the western continental border of North America, comparable to the Atlantic coast of the eastern United States today.

The expedition team was composed of four people in total, including the duo from UC and two field assistants. Arkle, who has participated in a

number of expeditions

during her time at UC, served as both a geologist and raft guide during the expedition of the mountain range, which is about the size of California.

“This expedition was a chance to meld two of my passions and skill-sets: to explore an extremely remote part of the world via raft and to be part of a scientific team, which is on the forefront of investigating a provocative geologic problem,” Arkle said.

Even though the expedition took place around the end of July and beginning of August, the team experienced a lot of precipitation, including snow, during their trip. The overcast conditions on some days made it more difficult for the UC team to make observations on the mountains’ topography, especially when part of the mountains were covered in fog.  However, Enkelmann and her team were still able to make some observations of the mountains and how they were built while on the expedition. For example, when studying the topography of the landscape, they noticed that the rocks and landscape appear to be lifting up.

Currently, Enkelmann has two undergraduate assistants in her lab who separate the samples into various minerals, which will later be analyzed in her thermochronology lab. Thermochronology is a geologic dating tool that gives geologists insight to how landscapes, such as mountain ranges, grow and wear away due to tectonic and surface-process interactions. A thermochronology date is used to understand the thermal history of a rock, or how the rock traveled to the surface where it was collected.

After the rock samples are crushed and minerals of interest are separated out in Enkelmann’s thermochronology lab, a microscope analysis is used to determine when a rock was at a temperature below the Earth’s surface. Depending on the outcome of the ongoing laboratory work, the Mackenzie Mountains expedition could potentially lead to further research for Enkelmann as the fieldwork allowed her to become familiar with both the Mackenzie Mountains and its rocks.