Remains of recent glaciers found near Mars’ equator suggest water ice may exist today at low latitudes.

Remains of recent glaciers found near Mars' equator suggest water ice may exist today at low latitudes.

A relict glacier near the Martian equator. Credit: NASA MRO HiRISE and CRISM False Color Composite / Lee et al. 2023

In a groundbreaking announcement at the 54th Lunar and Planetary Science Conference held in The Woodlands, Texas, scientists revealed the discovery of a glacier near Mars’ equator. Located in eastern Noctis Labyrinthus at coordinates 7°33′ S, 93°14′ W, this result is significant because it indicates the recent presence of surface water ice on Mars, even near the equator. This discovery raises the possibility that ice may still exist at shallow depths in the region, which could have important implications for future human exploration.

The surface feature identified as a “glacier” is one of several light colored deposits (LTDs) found in the area. Usually, LTDs consist primarily of light-colored sulfate salts, but this deposit also shows many glacier features, including fault fields and moraine bands. The glacier is estimated to be 6 km long and up to 4 km wide, and the surface height ranges from +1.3 to +1.7 km. This discovery indicates that the recent history of Mars may have been more watery than previously thought, which could have implications for understanding the planet’s habitability.

“What we found is not ice, but salt deposits that contain the detailed morphological features of a glacier. What we think happened here is that the salt formed on top of the glacier while maintaining the shape of the ice below, down to such details as the SETI Institute planetary scientist,” said Dr. Pascal Lee, a planetary scientist at the SETI Institute. and the Mars Institute, lead author of the study: “Fault Fields and Cumulus Bands.”

The presence of volcanic material covering the area indicates how sulfate salts formed and preserved the imprint of a glacier beneath. When freshly erupted lava material (a mixture of volcanic ash, pumice, and hot lava blocks) comes into contact with water ice, sulfate salts such as those that normally form light-colored Martian deposits may form and accumulate in a hard, crustal salt bed.

“This region of Mars has a history of volcanic activity. Where some volcanic material came into contact with icy ice, chemical reactions were taking place at the boundary between the two to form a solid layer of sulfate salts,” Saurabh explains. Chobham, a graduate student in the University of Maryland’s Department of Geology, and co-author of the study. “This is the most likely explanation for the hydrated and hydroxylated sulfate we are observing in this light-colored sediment.”

Over time, as erosion removed the overlying volcanic material, it became a crustal layer of sulfates reflecting the glacial ice beneath, which explains how salt deposits now appear, providing unique features to glaciers such as faults and moraine ranges.

Remains of recent glaciers found near Mars' equator suggest water ice may exist today at low latitudes.

Interpretation of Relict Glacier’s features. Credit: Lee et al. 2023

“Glaciers often present distinct types of features, including fringe-marginal rifts, volutes and tic-tac-toe fields, and also moraine groups and foliation. We are seeing similar features in this light-coloured deposit, in shape, location and scale,” said John Shute, A geologist at the Mars Institute, an experienced ice guide in the Arctic and Antarctica, and a co-author of this study, it’s very interesting.

The subtle features of the glacier, the associated deposits of sulfate salts, and the overlying volcanic material are all highly dispersed by impacts and must be geologically young, likely an Amazonian, the most recent geological period that includes modern Mars. “We’ve learned of glacial activity on Mars at many locations, including near equator in the distant past. And we know of recent glacial activity on Mars, but so far, only at high latitudes. A relatively small glacier at this location, he told me, tells us that Mars has had surface ice recently, even near the equator, which is new.”

It remains to be seen if water ice can still be preserved beneath the light-colored sediments or if it disappears altogether. “Water ice, at the moment, is not stable on Mars itself near the equator at these altitudes. So it’s not surprising that we haven’t detected any water ice on the surface. It’s possible that all the water ice in the glacier has sublimated away now. But there is also the possibility that some of them may still be protected at shallow depths under sulfate salts.”

The study draws an analogy with ancient glacial islands on the salt lake basins, or Salar, in the Altiplano in South America. There, ancient glacier ice has been sheltered from melting, evaporation and sublimation under blankets of bright salts. Li and colleagues hypothesize a similar situation to explain how sulfate salts on Mars might be able to provide protection for sublimated ices at the planet’s low latitudes.

If there is still water ice preserved at shallow depths at a low latitude on Mars, there will be implications for science and human exploration. “The desire to land humans in a place where they can extract water ice from the Earth has prompted mission planners to look at higher latitude locations. But the latter environments are usually cooler and more challenging for humans and robots. If there are tropical locations where they can be found, Lee said. With ice at shallower depths, we’ll have the best of both environments: warmer conditions for human exploration while still having access to ice.”

But Li warned that there was still more work to be done: “We now have to determine if and how much.” water ice They may already be present in this lagging glacier, and whether other light-colored sediments may also contain or contain ice-rich substrates. ”

more information:
Pascal Lee et al A glacier near the Martian equator: evidence of recent glaciation and volcanism in the eastern labyrinth Noctis Labyrinthus (2023)

Introduction of
SETI Institute

the quote: Recent Glacier Remains Found Near Mars’ Equator Indicate Possible Water Ice Today at Low Latitudes (2023, March 15) Retrieved March 15, 2023 from 03-modern-glacier-mars-equator-ice.html

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