The discovery raises the possibility that ice still exists at shallow depths, which could have implications for future exploration.
The structure of a glacier has been located in the equatorial region of Martea relevant finding that implies the recent presence of surface water on Mars, including at the equator.
This discovery –located in eastern Labyrinth of the night at coordinates 7 33′ S, 93 14′ W–, raises the possibility that shallow ice still exists in the area, which could have significant implications for future human exploration.
The finding has been presented at the 54th Lunar and Planetary Science Conference held in The WoodlandsTexas
The surface feature has been identified as a “leaving the glacier”. In geology, the term relict refers to structures or minerals from a parent rock that did not undergo metamorphic changes when the surrounding rock did, or to rocks that survived a destructive geologic process.
This relict glacier is one of many light-toned deposits (LTD) found in the region. LTDs usually consist primarily of light-colored sulfate salts, but this deposit also shows many of the characteristics of a glacier, including rift fields and moraine bands.
The glacier is estimated to be 6 kilometers long and up to 4 kilometers wide, with a surface elevation ranging from +1.3 to +1.7 kilometers. This discovery suggests 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 have found is not ice, but rather a salt deposit with the detailed morphological characteristics of a glacier. What we think happened here is that salt formed on top of a glacier while retaining the shape of the ice below, down to details such as crack fields and moraine bands,” said the Dr. Pascal Leeplanetary scientist Mars Institute y SETI. Instituteand the lead author of the study.
The presence of volcanic materials covering the region suggests how sulfate salts might have formed and preserved the footprint of a glacier below. When newly erupted pyroclastic materials (mixtures of volcanic ash, pumice, and hot lava blocks) come into contact with water ice, sulfate salts such as those commonly forming light-hued deposits on Mars can form and accumulate in a crusty, hardened layer of salt.
“This region of Mars has a history of volcanic activity. And when some of the volcanic material came into contact with the glacier ice, chemical reactions would have taken place at the boundary between the two to form a hardened layer of sulfate salts.” Explain Saurabh Shubham, graduate student in the Department of Science at the University of Maryland. Geologist, and co-author of the study. “This is the most likely explanation for the hydrated and hydroxylated sulfates we observed in this light-toned deposit.”
Over time, with the erosion that removed the volcanic materials that covered it, a layer of sulfates that reflected the ice of the glacier below was exposed, which would explain why a salt deposit is now visible, which presents unique characteristics of glaciers. such as cracks and moraine bands.
“Glaciers often display distinctive types of features, including fringe, spreading, and tic-tac-toe fields, as well as moraine bands and foliation. We are seeing analogous features in this light-toned deposit, in shape, location, and scale. It’s very intriguing,” said John Rubblea geologist at the Mars Institute, expert guide to Arctic and Antarctic ice fields, and co-author of this study.
The fine-scale features of the glacier, its associated sulfate salt deposit, and overlying volcanic materials have very few impact craters and must be geologically young, probably Amazonian in age, the last geologic period that includes modern Mars. “We have known about glacial activity on Mars in many places, including near the equator in the more distant past. And we know about recent glacial activity on Mars, but so far, only at higher latitudes. A relatively young relict glacier on this location tells us that Mars experienced surface ice in recent times, even near the equator, which is new,” Lee said.
It remains to be seen if the water ice is still preserved under the light-colored deposit or if it has disappeared completely. “Water ice is currently not stable on the very surface of Mars near the equator at these elevations.. So it is not surprising that we are not detecting any water ice on the surface. All the water ice on the glacier may have already sublimated. But there is also the possibility that part of it is still protected at a shallow depth under the sulfate salts.”
The study draws an analogy with ancient ice islands in salt lake beds, or salars, of the Altiplano in South America. There, the ancient glacial ice has remained protected from melting, evaporation, and sublimation under layers of glowing salts. Lee and his coauthors hypothesize a similar situation to explain how sulfate salts on Mars might offer protection to ice vulnerable to sublimation at low latitudes on the planet.
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