By Shashank Anand, 2023 Science Communication Intern

Life as we know it is intricately tied to the presence of water, adequate energy, and the passage of time. The quest to understand the “water puzzle” of Mars, the enigmatic red planet, fuels the curiosity of scientists worldwide (Fig. 1). With hopes of discovering hints of life, Marisa Palucis of Dartmouth College delved into Mars’ 4.5-billion-year-long history. Palucis presented her research at GSA Connects 2023 in a session about geomorphology and landscape evolution on Mars.

Mars’ surface is a desolate expanse, devoid of liquid water, with temperatures plunging to as low as –225 °F. Yet tantalizing surface features—gullies, alluvial fans, and riverbed-like formations—hint at water on the planet in the distant past (Fig. 2). This raises questions about the “Water Chapter”: When did it occur, how did it shape the landscape, and to what extent? The challenge lies in unraveling the mysteries of the planet’s ancient water history when these sediment transport processes are dormant on present-day Mars.

Figure 1. Liquid water on Mars in the past? Credit: Getty Images.

Planetary geomorphologists adopt an innovative approach, using Earth’s peculiar landscapes under diverse climate and sediment transport processes to gain valuable insights into Mars’ atmospheric and surface conditions. Palucis conducted her research using the Meteor Crater in Arizona, which serves as Earth’s analog to Mars’ features (Fig. 3). Formed approximately 50,000 years ago under cooler and wetter conditions, the Meteor Crater became a crucial site for Palucis to explore how a landscape resembling ancient Mars has evolved amid significant climate change. Gullies on Meteor Crater’s walls, formed by debris flows—a slurry mixture of sediment carried by fluid down the slope—provide a unique window into Mars’ past.

Figure 2. Examples of gullies across Mars. Figure from Palucis and Morgan (2022). Credit: NASA/JPL/University of Arizona.

Palucis discovered that conventional analyses of deposits and erosional landforms at Meteor Crater underestimate total water inputs and the intensity and duration of those inputs. This insight challenges simplistic water budget analyses on the red planet, emphasizing the need to account for additional water required to trigger debris flows and the possibility of more water on ancient Mars. She aptly compares this to a pebble in a stream bed—a reminder that merely accounting for the water that just moves the pebble ignores all the times the river flows while the pebble remains stationary. She remarks, “A better understanding of the mechanics of sediment transport on steep slopes, and the associated water volumes and rates under different climate conditions, will help us develop more accurate models for Martian systems.”

Figure 3. Example of a gully on Mars (left) and gullies at Meteor Crater (right). Figure from Palucis et al. (2023). Credit: NASA/JPL-Caltech/University of Arizona; opentopography.org

As we pursue knowledge about Mars, each discovery unravels a piece of the intricate puzzle that defines the planet’s history. Through the lens of Meteor Crater, we gain a glimpse into Mars’ past, paving the way for more accurate interpretations and a deeper understanding of our celestial neighbor. Palucis’s exploration of Mars-analog environments, such as the Canadian Arctic, continues to further our understanding of the past and current Martian landscape. “I truly hope that we do find evidence of life in the coming decades,” says Palucis. The journey doesn’t end here; it’s an ongoing exploration that fuels our curiosity about life and the mysteries beyond our home planet.

Acknowledgements
This page was added to the online exhibit with the assistance of funding to Shashank Anand from the Geological Society of America.

References

Palucis, M.C., and Morgan, A.M., Extraterrestrial fluvial environments, in Shroder, J.F., ed., Treatise on Geomorphology: Cambridge, Mass., Academic Press, p. 994–1031, https://doi.org/10.1016/B978-0-12-818234-5.00006-7

Palucis, M., Morgan, A.M., Strauss, J.V., Rivera-Hernandez, F., Marshall, J.A., Menio, E., and Miller, R., 2023, Rates and processes controlling periglacial alluvial fan formation: Implications for Martian fans: GSA Bulletin, v 135, no. 3-4, https://doi.org/10.1130/B36459.1. 

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The GSA Science Communication Internship was a program offered at GSA Connects in Pittsburgh, Penn., designed for student attendees interested in science communication as a possible alternative career path.  Interns were paired with GSA’s Science Communication Fellow in order to gain experience in making science clear and exciting, under the tutelage of a professional writer.  Students were assigned to conduct interviews with presenters at the meeting and to compile summaries capturing the significance of the presenters’ work for a non-technical audience.  Media assignments and mentoring were useful learning experiences and exposure opportunities for students seeking to expand their knowledge into geoscientific reporting.