By Matthew Dawson, GSA Education Programs Manager
GSA Fellow Kathleen Counter Benison is a professor of Geology in the Department of Geology and Geography at West Virginia University, where she leads the Red Earth Observatory Research Group. Dr. Benison’s research focus is on sedimentary geology, geochemistry, geomicrobiology, paleoclimatology, and astrobiology, and she is a Return Sample Selection Participating Scientist with NASA’s Mars 2020 mission project science group. She is chair of GSA’s Limnogeology Division and Science Editor of Geology, one of GSA’s premier journals.
GSA had the chance to chat with Kathleen about her involvement in the science being performed by the Mars Perseverance rover.
GSA: What are your geological research interests here on earth, and how do those interests connect to Mars?
KB: I am fascinated with our ability to interpret environmental conditions, climate, and life from the past by studies of sedimentary rocks. I am particularly interested in the interactions among surface water chemistry, chemical precipitates such as salt minerals, weather and climate, and microorganisms. For ~ 20 years, I have been conducting field work and lab work on acid saline lake and groundwater systems in Western Australia. Here, the water pH is as low as 1.4, the salinity can be 10x saltier than seawater, and a rare suite of minerals precipitates. Despite the extreme conditions, there are diverse communities of microorganisms that live here, and are trapped in the salt minerals. I also study Permian red beds and evaporites, which formed in acid saline lakes and associated environments. Minerals such as halite and gypsum can develop fluid inclusions as they grow and these provide an extraordinary record of past conditions, including water chemistry and trapped microorganisms. There are some similarities in mineralogy, sedimentary structures, and diagenetic features between terrestrial acid saline lake deposits and some rocks found on Mars. Recent understanding of how life can thrive in extreme terrestrial environments, such as acid saline lakes, and how microorganisms and organic compounds can be preserved in minerals and rocks from those environments, has implications for the understanding of past habitability and the search for signs of ancient life on Mars. Knowing how to recognize signs of past water and biosignature potential in sediments and rocks is necessary for the best approach to unlocking Mars history of life.
GSA: What can the study of geology on Earth tell us about Mars? (And vice versa?)
KB: Mars and Earth are similar, but also different; currently, they have differences in surface temperature, atmospheric composition, and gravity. But they are both rocky planets, they are neighbors in the solar system, and they both have a history of the same general geologic processes: volcanism, glaciation, fluvial and eolian processes. So, our geologic knowledge of Earth gives us a starting point for understanding Mars. And whatever we learn about Mars expands our knowledge of planetary evolution. Knowing about Mars can ultimately teach us more about our home planet and provide us with possible scenarios about interactions amongst atmosphere, hydrosphere, lithosphere, and biosphere. As we humans ponder the current and future crises on Earth, such as climate change, environmental stress, and extinctions, all knowledge about both Earth’s past and history of other planets and moons, is helpful. Is life unique to Earth? How fragile is life? Answers to these questions are key to humankind’s own self-interest.
GSA: Tell us about your role with NASA’s Perseverance Rover, which recently landed on Mars. (As a geoscience educator and a geocacher, I’m especially interested in hearing about the cache of rock and sediment samples.)
KB: The Mars 2020 mission has goals of evaluating signs of habitability, sampling rocks and sediments with a high potential for biosignatures, and leaving deposits (or “caches”) of samples on Mars surface to be collected and returned to Earth in approximately 10 years by a Mars Sample Return mission. The Perseverance rover is the first robot on Mars that can collect samples. It contains a drilling mechanism on its arm. Each sample will be placed in a sample tube and sealed. The samples will be approximately the size of an adult human index finger. As a field geologist who has mailed hundreds of pounds of rocks, sediments, and waters from field sites to my lab, this seems like a tiny amount of sample. However, the small volume and light weight is necessary for returning the samples to Earth. In addition, thanks to many advanced analytical methods that can be performed in Earth labs, these small samples have the potential to provide a huge amount and diversity of data.
I am a member of a large team of dedicated scientists and engineers. Although much of our work is a group effort, there are subgroups charged with specialized tasks. I am one of 15 return sample participating scientists and our main job is to help select rocks and sediments to sample.
GSA: Is there anything in particular that you are hoping to learn from the Perseverance mission?
KB: Ultimately, I hope that we are successful in choosing and returning a suite of samples that both represent the diversity of the Jezero crater region, as well as have high potential for biosignatures. Personally, I hope to find and sample sediments and rocks with fluid inclusions because they may contain actual remnants of past martian waters and microbial life. But anything we find on Mars will teach us more about the planet.
GSA: How can the public—youth, in particular—learn more about the geology of Mars? Do you have any recommendations for places to visit right here on Earth that serve as interesting Mars analogues?
KB: Some terrestrial analogues for Mars are in remote locations, such as lakes in the dry valleys of Antarctica and acid salt lakes in the high Andes of Chile. However, the national parks of the western U.S., as well as many state parks, showcase spectacular geology similar to some of the landscapes and rock types we see on Mars. My favorite places at which one gets a feel for being on another planet are Death Valley, White Sands, and Zion National Parks. However, there are many other locations that can teach us about geology – local beaches, sand dunes, and rivers, to name a few.
In addition, NASA has some fantastic information about Mars, including educational material, on the NASA Jet Propulsion Laboratory (JPL) education website. You can even look online at images being sent daily from the two active NASA rovers on Mars, Curiosity and Perseverance.
GSA: As we begin to close this interview, I’d like to thank you for your service to GSA, as Science Editor of Geology, and Chair of the Limnogeology Division. Can you talk a bit about what GSA has meant for you and your career as a geoscientist?
KB: GSA has enriched my professional network, as well as helped me as a geoscience educator and researcher. Technical sessions, Division meetings, short courses, and field trips at GSA annual and section meetings, and GSA journals and other publications, have all been invaluable ways for me to learn about current geoscience advances, and to communicate my latest science. My students have benefitted as recipients of student membership and student research grants. It’s great to see their enthusiasm as they go to their first GSA meeting!
GSA: Is there anything else you’d like to share? Since March is Women’s History Month, is there a woman who has inspired you in your geoscience career?
KB: I graduated from three different universities for undergraduate, masters, and PhD programs in geology, but I only had one woman as a science professor, hydrogeologist Dr. Gwen Macpherson at the University of Kansas, who served on my doctoral committee. She showed me that women could be both successful academics and moms, something I had not seen previously.
To learn more about Kathleen’s research:
For more about Mars:
- NASA Mars 2020 website
- Geocaching on Mars with the Perseverance Rover
- Planetary Geology & EarthCache Sites