Houston: Mars once had salt lakes that went through wet and dry phases similar to Earth's, according to a study indicating that the climate of the red planet has "dried up" for a long time.
According to the researchers, including those from Texas A&M University in the United States, liquid water on Mars may have become unsustainable and evaporated as the planet's atmosphere became thinner and surface pressure became lower.
The study, published in the journal Nature Geoscience, noted that over 3 billion years ago the lake that was present in the Gale Crater – a huge 95-mile-wide rocky basin that has been explored with NASA's Curiosity rover since 2012 – passed by a drying episode possibly linked to the global drying of Mars.
The Gale Crater formed about 3.6 billion years ago when a meteor hit Mars, the study noted.
"Since then, its geological terrain has recorded the history of Mars and studies have shown that Gale Crater reveals signs that liquid water was present throughout its history, which is a key ingredient of microbial life as we know it," said the co-author of Marion Nachon of Texas A&M University. According to Nachon, salt ponds eventually formed during these drying periods. "It's hard to tell exactly how big these lagoons are, but the lake at Gale Crater has been around for long periods of time – from at least hundreds of years to perhaps tens of thousands of years," Nachon said.
The researchers said the salt lagoons on Mars are similar to some found on Earth, such as those in a region called the Altiplano, near the Bolivian-Peruvian border.
Nachon added that the Altiplano is a barren, high-altitude plateau where mountain rivers and streams "do not flow into the sea but lead to closed basins, similar to what used to happen at the Gale Crater on Mars." "This hydrology creates lakes with water levels strongly influenced by the climate. During arid periods, the Altiplano lakes become shallow due to evaporation and some even dry up completely," she said. According to the researchers, the weather on Mars may have fluctuated equally between the wettest and driest periods. The study also looked at the types of chemical elements present in liquid water present on the surface of the red planet at the time, and the kind of environmental changes that any life on Mars might have to deal with, if any.