Mineralogy on Mars points to a cold and icy ancient climate

June 8, 2018 by Kayla Zacharias, Purdue University
Researchers expect the volcanoes in Mars' Sisyphi Planum region to look similar to subglacial volcanoes on earth, such as Herðubreið in Iceland. Credit: Purdue University photo/Sheridan Ackiss

The climate throughout Mars' early history has long been debated—was the Red Planet warm and wet, or cold and icy? New research published in Icarus provides evidence for the latter.

Mars is littered with valley networks, deltas and lake deposits, meaning it must have had freely flowing water at some point, probably around 4 billion years ago. But climate models of the planet's deep past haven't been able to produce warm enough conditions to allow liquid water on the surface.

"There are people trying to model Mars' ancient climate using the same kind of models we use here on Earth, and they're having a really hard time doing it. It's difficult to create a warm ancient Mars because the sun was a lot fainter then. The whole solar system was cooler," said Briony Horgan, an assistant professor of earth, atmospheric and planetary sciences at Purdue University. "While a lot of people are using , we're coming at this from a unique perspective—what does the volcanic record of Mars tell us?"

Volcanism was abundant throughout Mars' early history. There are large, broad volcanoes on some of the planet's widely studied regions, but less is known about a region of low and smooth topography in the southern highlands known as Sisyphi Planum. Here, there are more than 100 flat-topped mounds known as the Sisyphi Montes, which could be volcanic in origin.

When volcanoes erupt beneath ice sheets and glaciers on Earth, the combination of heat and melt water create flat-topped, steep-sided mountains called "tuyas," or table mountains. When subglacial eruptions don't breach the surface of the ice, the tops of the volcanoes remain cone-shaped instead of becoming flat. The mineralogy produced during these events is unique due to the interaction between hot lava and cold glacial meltwater.

Sheridan Ackiss, a Ph.D. candidate at Purdue and lead author of the paper, used images from NASA's Compact Reconnaissance Imaging Spectrometers for Mars (CRISM) to find out if the mineral makeup of the region was consistent with subglacial volcanism.

CRISM detects both the visible range and shorter wavelengths of light, which helps the instrument's operators identify a broad range of minerals on the Martian surface. At visible wavelengths, the way light is reflected is strongly influenced by iron, whereas at infrared wavelengths, CRISM can pick up features from carbonate, sulfate, hydroxyl and water incorporated in mineral crystals.

"Each rock has a specific fingerprint, and you can identify that with reflections of light," Ackiss said.

The findings identify three distinct mineral combinations in the region, dominated by gypsum, polyhydrated sulfates and a smectite-zeolite-iron oxide mixture—all of which have been associated with volcanoes in glacial environments.

"We now have two sets of data, minerals and morphology, that say there had to have been ice on Mars at some point in time," said Ackiss. "And it was probably relatively late in Mars' history."

Ackiss' team hopes their findings can be used as a reference point for other regions on Mars with a volcanic history. If researchers could find evidence for volcanic activity under ice sheets elsewhere, it would solidify the case for a very cold ancient Mars. But fear not, space enthusiasts, this doesn't eliminate the possibility of past life on Mars.

"Even if Mars was a cold and icy wasteland, these interacting with ice sheets could have created a little happy place for microbes to exist," Horgan said. "This is the kind of place you'd want to go to understand how life would've survived on Mars during that time."

Explore further: Found: Clues about volcanoes under ice on ancient Mars

More information: S. Ackiss et al, Mineralogic evidence for subglacial volcanism in the Sisyphi Montes region of Mars, Icarus (2018). DOI: 10.1016/j.icarus.2018.03.026

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4 comments

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Mark Thomas
4 / 5 (4) Jun 08, 2018
But climate models of the planet's deep past haven't been able to produce warm enough conditions to allow liquid water on the surface


Well then the water was either under the ice or (more likely) you need to adjust your models. NASA's elevation map of Mars in combination with other evidence makes if very clear there were massive amounts of liquid water on Mars at one or more points in the past. What evidence? (I can hear you asking.) You need to do your own research and NASA's conclusions and the basis for them.

https://astropedi...1024.jpg
rrwillsj
1 / 5 (4) Jun 08, 2018
Mark, are you insisting that their data be adjusted to your opinion? Otherwise, their collected data cannot be as reliable as your interpretations of someone else's data?

Please correct me if I am misstating your opinion.

In my opinion, all these recent articles in apparent conflict? Are actually attempting to describe possibilities for what little evidence we have collected for different ages of the Mars-Archaean Epoch.

Each researcher offering different speculations about what part of the elephant they are running their hands over.

In other words, Mars 1 billion years ago was not the same as the Mars 4 billion years ago. With major changes again every time you add or subtract a billion years.

Compare with the Grand Canyon or the Canadian Shield. We see an endless geological transformation. That is still continuing. No matter what we may choose to believe.

Some people are grousing that they never got to ride a dinosaur. Cause Noah forgot to board them.
AllStBob
5 / 5 (1) Jun 10, 2018
It is important we don't fit the data to the models which predict conditions for life. It is also equally possible there was flowing water on Mars and no life arose.
torbjorn_b_g_larsson
not rated yet Jun 25, 2018
"an Early–Late Hesperian age (i.e. 3.71–3.37 Ga) for Syrtis Major volcanism is suggested". [Volcanism and Tectonism Across the Inner Solar System, p30.] Plenty of time for both free water ~4 Ga as Gale crater suggest, then ice cover later as today's climate suggest.

Coincidentally, the same climate model problem for early Earth under the weak young Sun was likely solved as this paper was prepared. Erosion with an ocean and ~1 atm of CO2 atmosphere seems to have sufficed and self regulated to boot. Mars could have had the same at ~4 Ga. [ https://www.astro...sewhere/ ]

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