Water on Ancient Mars?

 We all need a break from political news, so here's a cool story, slightly condensed, from Universe Today on the presence of water on ancient Mars.

There was Hot Water on Mars 4.45 Billion Years Ago

Earth and Mars were very similar in their youth. Four billion years ago, both planets had vast, warm seas. But while Earth retained its oceans, the waters of Mars evaporated away or froze beneath its dusty surface. Based on geological studies, we know that Earth’s water cycle seemed to have stabilized early. From about 4.5 billion years ago to today, water has had a stable presence on Earth. For Mars, things are less clear. Clay minerals cover about 45% of the Martian surface and date to what is known as the Noachian period, which ranges from 4.1 to 3.7 billion years ago. During the Amazonian period, which dates from 3 billion years ago to today, Mars seems to have been mostly dry. We have little evidence of the earliest period of Mars, known as the pre-Noachian. But a new study peels back the Martian ages to give us a glimpse of the first epoch of Mars, and it comes from a Martian meteorite known as Black Beauty.

This new study doesn’t focus on Black Beauty as a whole, but rather on small crystals of zircon embedded within it. These crystals can be dated to 4.48–4.43 billion years, meaning they formed in the Pre-Noachian period. What’s interesting is that the crystals have layers of iron, aluminum, and sodium in a pattern known as oscillatory zoning. Since zircon is igneous in origin, this kind of banding is almost unheard of in zircon crystals. On Earth, there is only one place where such a pattern occurs, which is in hydrothermal geysers such as those found in Yellowstone National Park.

The presence of these crystals in Black Beauty proves not only that Mars was wet during the Pre-Noachian period, but that it was geologically active with warm thermal vents. Similar vents on Earth may have triggered the formation of life on our world. Whether life ever existed on Mars is still an unanswered question, but it is clear that the conditions for life on Mars did exist in its earliest history.

Reference: Gillespie, Jack, et al. “Zircon trace element evidence for early hydrothermal activity on Mars.” Science Advances 110.47 (2024)