Analysis of a Martian meteorite has determined when liquid water existed on the Red Planet.

Approximately 10.7 million years ago, a significant impact event occurred on Mars, resulting in the ejection of rock fragments into space, one of which eventually landed on Earth. Recently, an international research team utilized an innovative method to study an ancient meteorite known as Lafayette and discovered that, prior to its arrival on our planet, it had been in contact with liquid water.

2024-11-17 10:01:01https://naked-science.ru/article/astronomy/analiz-marsianskogo-meteo

Lafayette is shrouded in mysteries: in 1931, a meteorite was found in the storage of Purdue University (USA), but nothing more is known about this discovery. The fragment itself, however, holds significant information about the history of the Red Planet and belongs to a group known as nakhlites—volcanic rocks that formed on Mars approximately 1.3 to 1.4 billion years ago and were ejected into space as a result of an asteroid impact (around 10.7 million years ago).

Meteorites directly associated with Mars are rare and allow scientists to learn more about the past and geology of our neighboring planet. It has long been known that this fragment of Martian rock once came into contact with water; however, the exact timeframe was only established recently. It is worth noting that Martian meteorites are identified by their isotopic ratios, which are unique to each planet in the Solar System (excluding Earth and the Moon, as the latter formed from terrestrial material).

The research results, published in the journal Geochemical Perspectives Letters, indicated that Martian rocks interacted with water about 742 million years ago (with an accuracy of ±15 million years). This is currently the most precise estimate of when liquid water was present on the surface of the Red Planet in significant quantities.

Since traditional methods were not sufficiently accurate, a team of scientists from the University of Alberta (Canada) and the University of Glasgow (UK) employed an advanced 40Ar/39Ar dating method, which measures the ratio of argon isotopes, allowing for the determination of the mineral formation time.

Using this method, researchers accurately dated iddingsite within Lafayette—a reddish-brown mixture of silicates that forms as a result of the interaction of rocks with liquid water. The results showed that liquid water was present on the Martian surface about 742 million years ago. This suggests that the water activity on the Red Planet is not related to the initial formation of the rocks or known impact events, as previously thought.

The authors of the study also proposed that volcanic activity could have been responsible for the presence of liquid water: the heat from these geological processes likely melted the local permafrost, thereby creating brief conditions for chemical interactions between liquid water and rocks.

Such localized hydrological cycles on Mars during the Amazonian period (a geological period characterized by cold and dry conditions that began around 2.9 billion years ago and continues to the present day) occurred infrequently but were not exceptional.

Thus, the research findings are significant for understanding the geological and climatic history of Mars and support the idea that the planet may still be geologically active, as there could be heat sources beneath its surface capable of creating conditions suitable for liquid water.