Understanding Surficial Processes in the Himalayan Orogen

For geology graduate student Jason Dortch, work is play.

Considering how he became interested in the field, it is no surprise. When he started his undergraduate courses at Riverside Community College, he only knew his direction in life would take him into the sciences. Then he discovered a geology class that offered the hiking aficionado some practical knowledge: learning how to read maps.

“I like to go hiking, so I figured learning how to read a map might be a good idea,” Dortch says.

When the professor showed a video on the first day of class that featured a geologist climbing up the rim of a volcano to collect lava samples, Dortch was hooked. He enrolled at University of California, Riverside, where he received his BS in geology.

Now, Dortch is a PhD student studying mountain landscape evolution at University of Cincinnati under

Geology Professor

Lewis Owen, whom he followed from UC Riverside to continue collaboration. He received his master’s here in 2007 while studying glacial geomorphology in Alaska.

Dortch hopes to obtain his PhD by next summer in tectonic geomorphology and paleoclimatology, a topic that puts the self-proclaimed adrenaline junkie into hair-raising situations all in the name of research.

He has dangled off cliffs, motorcycled over mountain peaks and cross-country skied 450 miles in the Alaskan and Himalayan mountains for his passion.

“In simple terms, I’m trying to link processes that operate on the Earth’s surface to the processes that operate in the Earth’s interior,” he says. “My backcountry skills and ability to be comfortable in traversing various terrains, in addition to main roads, helps me spread out the spatial distribution of where I’m collecting data, so I can learn a lot more. I get to access areas that aren’t easy to get into at all.”

Dortch has spent the past four summers working in the Ladakh region, a collection of high altitude mountain ranges in the Indian Himalaya. Utilizing thermochronology and cosmogenic dating on rock samples, he analyzes the rate, magnitude and timing of landscape evolution.

Two mechanisms are known to increase the height of mountains: tectonic convergence and incision. Dortch has a particular interest is what is referred to by geomorphologists as the chicken or egg question regarding these mechanisms: did uplift of the Himalaya cause global cooling and increased glaciation, or did global cooling and subsequent glacial incision induce the uplift of the Himalayan peaks?

“We know that the Tibetan Plateau was created by the Indian plate colliding with the Eurasian plate—but it was followed shortly by global cooling; the question is which one is the dominant driver,” Dortch explains. “Did glacial incision cause the mountain peaks to uplift or did the uplift cause the glaciation? We don’t know which one caused the other, but they’re definitely related.”

These questions are what got Dortch interested in tectonic geomorphology, a relatively new field that will bear key information about the effects of climate change on landscape evolution.

“It’s complicated,” Dortch says about his interest in the topic. “If I can sit for five minutes and not wrap my head around a subject, I’m intrigued by it.”

Though he has a year left in the geology program, Dortch has already been offered a few postdoctoral fellowships. While not sure of his ultimate plan, he learned about an opening in Argentina that would include scaling a volcano for data collection—a feat that would whet his adrenaline whistle and help him explore tectonic geomorphology on a new continent simultaneously.

“My colleague, Lindsay Schoenbohm, is doing work on the Puna Plateau in Argentina. When she asked two students if they wanted to go up a 17,000-foot volcano to collect samples, they passed on it,” he says. “You’re kidding me, right? I can’t wait to do that kind of stuff.”