Chloride deposits are indicators of the presence of water on early Mars and have important implications for understanding the Martian climate and habitability. Color and Stereo Surface Imaging Systems Using the spacecraft (CaSSIS) aboard the European Space Agency's (ESA) Mars Trace Gases Explorer (TGO), planetary researchers conducted a planet-wide search for chloride-bearing deposits in Terra Sirenum and other parts of Mars.
This CaSSIS/TGO image shows chloride-bearing deposits (purple-colored scaly waves) in Terra Sirenum on Mars. Image credit: ESA/TGO/CaSSIS.
“Mars is currently a desert world, but around 3.5 billion years ago it was covered by rivers, lakes and possibly oceans,” said University of Bern researcher Valentin Bickel and his colleagues.
“The Cold Period began as Mars lost its magnetic field, could no longer retain its atmosphere, and water evaporated, froze, or became trapped within the surface.”
“Over time, the water disappeared, leaving behind mineral fingerprints on the surface.”
In this study, the researchers used neural networks to map potential chloride-bearing deposits in CaSSIS images across a large portion of Mars.
They identified a total of 965 potential chloride deposits ranging from 300 to 3,000 metres in diameter.
“These salt deposits probably formed from shallow pools or brines that evaporated in the sun,” the scientists said.
“Similar methods are used in saltwater pools on Earth to produce salt for human consumption.”
“Highly salty water could be a haven for life and an indicator of habitable parts of Mars,” the researchers added.
“Due to the high salinity, the water remains liquid even at minus 40 degrees.”
“The presence of chloride deposits, pictured above, and their direct association with liquid water, make areas like Terra Sirenum good targets for future robotic missions to search for signs of life.”
“While chloride-bearing terrains are not noticeable in regular black-and-white images, they show up as a distinct purple color in color infrared images, making CaSSIS a unique tool for studying the distribution of salts across Mars.”
“Our paper contains never-before-seen data that will help us better understand the distribution of water on Mars' distant past,” they said.
“TGO continues to image Mars from orbit to understand the planet's ancient past and potential habitability.”
“Not only will the spacecraft send back stunning images, it will also provide the best inventory of atmospheric gases and map water-rich areas on the planet's surface.”
“Understanding the history of water on Mars and whether it once allowed life to thrive is at the heart of ESA's ExoMars mission.”
Team paper Featured in this month's journal Scientific Data.
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VT Bickel others2024. Global dataset of potential chloride deposits on Mars identified by TGO CaSSIS. Scientific Data 11,845;doi: 10.1038/s41597-024-03685-3
Source: www.sci.news
