EAPS graduate student examines Martian and Earth volcanoes


Sheridan Ackiss

Sheridan Ackiss stands in front of the 5,897 meter Cotopaxi Volcano.

Satellite imaging wasn’t enough for Sheridan Ackiss, a PhD student in the Department of Earth, Atmospheric, and Planetary Sciences.

Ackiss followed up her internationally recognized, NASA-backed findings on Mars’ ancient volcanic history with a trip to study the volcanoes of Earth.

By studying images retrieved from NASA’s Mars Reconnaissance Orbiter’s mineral-mapping spectrometer, Ackiss and her team found evidence for volcanoes in a southern region of the Red Planet known as Sisyphi Montes. These volcanoes are covered in different types of rocks. Those rocks tell a story suggesting that these volcanoes once erupted under ice.  For NASA, this volcanic and icy history could help them learn more about past Martian climate and the history of its potentially life-sustaining water.

But getting to see Mars’ ancient, under-ice volcanoes up-close is out of the question, at least for a long, long time. Ackiss decided to take a trip to Ecuador to compare and contrast the volcanoes she is researching from afar in EAPS Prof. Briony Horgan’s lab with some of Earth’s most active volcanoes within the majestic Andes Mountains.

“I think volcanic processes and behaviors are the same on both planets,” said Ackiss, who is also a NASA Earth and Space Science doctoral fellow.

Ackiss, fellow EAPS graduate student Marie McBride, and students from other universities joined the South Dakota School of Mines’ Volcanology Field Camp to put on their hiking boots, grab their hammers and investigate lava flows, compositions, deposits and the surrounding rocks of Ecuadorian volcanoes from May 17 to June 3. While her South Dakotan peers concentrated on Earth stones, Ackiss was still thinking of the Martian minerals.

“I wanted to go and see the deposits first hand to  know what I’m looking at on Mars,” said Ackiss, who worked for NASA’s Goddard Space Flight Center before arriving to Purdue. “We can’t look at images from Mars and say ‘This is a layer of pumice followed by a layer of dirt’ mostly because its not that definitive. As planetary scientists, we have to look at all possible angles to verify what we think we are seeing. Everything has to be non-interpretive. So, we would say something like, ‘This is a light-toned layer followed by a dark-toned layer’.”

While Ecuador is about the size of Colorado, it still has tremendously diverse geography – rainforest, mountains, beaches and islands. Lucky for Ackiss, volcanoes touch all of such Ecuadorian regions. Ackiss conducted field work at the Tungurahua stratovolcano, the freezing Cotopaxi (3,750 meters above sea level) stratovolcano, and Galapagos Islands’ shield volcanoes.

“It was an amazing learning experience for me,” Ackiss said. “It’s made me really rethink things for my research. For Mars, we look at things from the five to 10 to 50 kilometer scales. On Earth, it’s a centimeter scale.”

Mars focus

Horgan and Ackiss are part of the upcoming NASA Mars 2020 rover mission. Horgan has worked on the science team for the $2.5 billion rover’s camera since 2014.

The heavy Mars lean in the department will remain as NASA and millions of planetary science fans consistently have one eye on the Red Planet.

Since the region of Mars that Ackiss studies is near the planet’s south pole, it’s much too cold, treacherous and remote for a rover to land. NASA is banking on researchers like Ackiss to reveal as much as they can about Earth’s neighbor. The Sisyphi Montes will be inaccessible for many years.

“We’re sending rovers. We’re trying to get samples returned and we’re trying to send humans,” Ackiss said. “I think my research is interesting because it’s not accessible to the rovers or the landing sites. We learn so much from the rovers but we learn about planet-wide processes thanks to the satellites.”

The moon, too

Ackiss’ work, as well as McBride’s, is applicable to volcanic studies on Earth’s moon.

McBride said the “glassy” deposits from ancient volcanic activity could contain oxygen for extraction for future lunar missions or settlements. Her work centers on mapping and characterizing these areas for possible future exploration.

“I’m working on eruption styles that caused these different deposits we see all over the moon,” McBride added.

Ackiss assured there is no Mars vs. the moon rivalry in their office.

“I’m pro going back to the moon before going to Mars,” Ackiss said. “The moon could serve as a base. Land on the moon and then go to Mars from the moon.”

Ackiss and group

Ackiss (fifth from the right) and the Ecuador group in front of the Tungurahua Volcano.

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