Desert digs: Adventures in Atacama

By Kristen Carlson

The Atacama Desert in Northern Chile is almost like another planet.

It is so arid that virtually no organisms exist there.

 It is so dry that when the indigenous people died and were buried in large woven baskets, their bodies, including their hair, were perfectly preserved because of the lack of microorganisms to break down their bodies' organic material.

Jason Rech, assistant professor of geology, began his research on the Atacama in 1998 when he was a graduate student at the University of Arizona. As Rech put it, he jumped at the chance to get involved.   This led to the research he did for his dissertation, which focused on the last 20,000 years of climate change.

When Rech joined Miami in 2002 he began a new project to look at climate change over the last 20 million years in the Atacama. This Chilean desert is said to be one of the driest and oldest in the world. It sweeps across nearly 125 miles of South America and stretches 700 miles between the Pacific and the Andes Mountains.

For the past three years, Rech and his team, including his colleague and another assistant professor, Brian Currie, have worked to find out precisely how old it is, why it is so dry, and whether the uplift of the Andes led to the creation of the desert.

Rech and his colleagues already have come to some important conclusions.

"Some researchers suggest that the extreme aridity of Atacama began about 3 million years ago, yet our data conclusively shows that this extreme aridity began at least 10 million years ago."   Rech said.

They also have been able to document a significant amount of uplift in the last 8 million years.   "Our best estimate from the displacements of fossil soils is that there has been about 1 to 1.5 kilometers of uplift in the last 8 million years.   This is important to understanding the uplift history of the Andes," Rech said.

The study is currently being funded through Miami grants, including the Hampton Fund.

On Rech's various trips to the Atacama -- which take place in our summer, which is South America's winter -- he has even brought along some students, including undergraduate Eric Shullenberger.

Shullenberger is a senior geology major who has been involved with the Atacama study since the summer of his sophomore year.

"The desert itself was unlike anywhere else I have ever visited," Shullenberger said. "The nights were frigid and quite windy. The days were hot and breezy."
      

The scientists camp without the need for tents. The silent nights in the desert threaten no rain and no insects. Shullenberger said the fieldwork tended to be very strenuous, often consisting of hiking steep terrain on loose rock. Rech and his team learned quickly that keeping an ample amount of survival supplies - including food and water -- was crucial to manage the desert camp-outs. "An empty stomach was usually temporary, but a dry palate was not." Shullenberger said. 

All that hard work goes into collecting soil and rock samples for oxygen and carbon isotopes, mineralogy and salt content analyses.   "Most of our work is based on buried soils and old marsh and lake deposits," Rech said.

When he returns from Chile to his lab in Shideler Hall, he analyzes the data and works some of what he's learned into the geology courses he teaches.

"I hope to continue this new line of research for quite some time.   Many other scientific groups, such as other academic institutions and NASA are starting to do research in the Atacama," Rech said.

This vast desert, Rech explained, is probably the best analog for interpreting land forms and investigating potential life on other planets, such as Mars. That's because Mars is incredibly arid, and as far as we know, no organisms exist there - almost like the Atacama.

Read more of Kristen Carlson's articles:

Del Rio-Tsonis