The analysis of a mineral present in a Martian meteorite that fell to Earth revealed traces of water on Mars dating back to 4.45 billion years ago according to new research.
The zircon grain may contain the oldest direct evidence of hot water on the Red Planet, which means it is possible that environments such as hot springs once existed on Mars, associated with the emergence of life on Earth.
The discovery opens new avenues for understanding whether Mars was ever habitable in its ancient past. It also adds further support to observations already collected by the fleet of spacecraft orbiting and exploring the Red Planet, which have detected evidence of where rivers and lakes once existed on the Martian surface.
However, key questions remain, such as when exactly water appeared on Mars and how it evolved – and disappeared – over time.
Scientists analyzed a sample of the “Black Beauty” meteorite, also known as NWA 7034, found in the Sahara Desert in 2011. The meteorite was ejected from the Martian surface after another celestial object hit the planet between 5 million and 10 million years ago, and its fragments have served as a fundamental source for studying ancient Mars for years.
The new study, published in the journal Science Advances on November 22, it focused on a single grain of the mineral zircon found inside the meteorite. The team’s analysis shows that water was present just 100 million years after the planet’s formation, suggesting that Mars may have been able to support life at some point in its history.
“Our data suggest the presence of water in the crust of Mars at a time comparable to the first evidence of water on Earth’s surface, about 4.4 billion years ago,” said study lead author Jack Gillespie, a researcher at the College of Mars. of Geosciences and Environment at the University of Lausanne, Switzerland, in a statement.
“This discovery provides new evidence to understand the planetary evolution of Mars, the processes that occurred on it and its potential to have harbored life,” he added.
Minerals as time capsules
The rocks may hold the answers to some of the biggest remaining questions about Mars, including how much water was present and whether life ever existed on the planet. This is why meteorites like Beleza Negra are of so much interest to scientists.
Carl Agee, professor and director of the Meteoritics Institute at the University of New Mexico, first introduced the space rock to the scientific community in 2013.
“[O meteorito Beleza Negra] contains hundreds of fragments of rocks and minerals, each a different part of the 4.5 billion years of Martian history,” said study co-author Dr. Aaron Cavosie, planetary scientist and senior professor at the Martian Space Science and Technology Center. Curtin University, by email. “It is the only source of pieces for the geological puzzle of pre-Noachian Mars.”
The Noachian period occurred from 4.1 to 3.7 billion years ago, and little is known from direct measurements dating back to the pre-Noachian period on Mars, between 4.5 billion and 4.1 billion years ago, although It’s crucial to understand why it serves as the first page in the book of Mars history, Cavosie said.
But Black Beauty revealed some of its secrets. Many of the rock fragments the meteorite contains show that the Martian crust withstood multiple impacts, causing a massive amount of shaking on the planet’s surface, he said.
The space rock also contains the oldest known pieces from Mars, including the oldest zircons, Cavosie said. Zircon, used in products such as jewelry, ceramic tiles and medical implants, is a tough mineral that can help scientists look into the past and determine the conditions present when it crystallized, including the temperature at the time and whether the mineral interacted with water.
“Zircon contains traces of uranium, an element that acts like a natural clock,” said Gillespie, who was a postdoctoral researcher in Curtin University’s School of Earth and Planetary Sciences at the time of the study. “This element breaks down into lead over time at a precisely known rate. By comparing the proportion of uranium to lead, we can calculate the age of crystal formation.”
The zircon found in Black Beauty was not altered by its trip to Earth nor by its fiery entry into our planet’s atmosphere before falling into the Sahara, as it was protected by its location inside the meteorite, Cavosie explained.
During analysis of the zircon grain, the study team detected unusual amounts of iron, sodium and aluminum, suggesting that water-rich fluids left these traces in the zircon when it formed 4.45 billion years ago. Such elements are not usually found in crystalline zircon, but the researchers’ atomic-scale studies showed that the elements were incorporated into the crystalline structure and lined up like fruit stands in a market, Cavosie said.
“We could see through the patterns of how [o ferro, alumínio e sódio] are found within the zircon that they were incorporated into the grain as it grew, like layers in an onion,” he explained.
On Earth, zircons from hydrothermal systems — which form when water is heated by subsurface volcanic activity, such as the upward flow of hot magma — have patterns similar to those found in Beleza Negra. If hydrothermal systems existed in the Martian crust 4.45 billion years ago, it is likely that liquid water reached the surface.
“Our experience on Earth shows that water is essential for habitats capable of supporting life,” Cavosie said. “Many environments on Earth host life in hot water systems, including hot springs and hydrothermal vents. Such environments may have given rise to the first forms of life on Earth. Our new study shows that Mars’ crust was warm and wet in the pre-Noachian period, meaning habitable environments may have existed at that time.”
Getting to know Mars a little better
Cavosie is curious to determine whether hydrothermal systems like hot springs were prevalent when magma was helping to form the Red Planet’s crust between 4.48 billion and 4.43 billion years ago or whether they were more one-off.
“If hydrothermal systems were a stable feature on early Mars, this would indicate that habitable conditions may have persisted for a considerable period,” Cavosie said. “This is now a testable hypothesis that can be addressed by collecting more data on Martian zircons.”
Until samples can be returned directly from Mars, the Beleza Negra meteorite is one of the best windows into understanding how the Martian crust formed and what the early surface of Mars was like, said Briony Horgan, co-investigator on the Perseverance rover mission and professor of planetary science at Purdue University in West Lafayette, Indiana. Horgan did not participate in this study.
Finding evidence of subsurface hydrothermal systems from a tiny grain of zircon aligns with scientific theories about how much water and volcanic activity existed on ancient Mars, she said. And these first potentially habitable environments would have been shielded from radiation by a strong planetary magnetic field, which Mars does not have today, Horgan added. Scientists are still trying to explain how the red planet lost its protective magnetic field.
The Perseverance rover is currently climbing the rim of Jezero Crater on Mars, an ancient lake that was once filled with water 3.7 billion years ago. Some of the rocks the rover found may have been formed by hydrothermal systems, Horgan said. The rover will collect samples from the rocks because they may preserve evidence of ancient microbial life.
“As much as meteorites can tell us, we can do even better with a carefully selected, intact rock sample from a known location on Mars with good geological context,” Horgan said. “So this paper is a great motivation to bring our Mars samples back to Earth to study in the same level of detail in the coming years.”
This content was originally published in Meteorite found on Earth may have new clues about water and life on Mars on the CNN Brasil website.
Source: CNN Brasil
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