Certain minerals from the Martian crust in the meteorite are oxidized, suggesting the presence of water during the impact that created it and shot toward Earth.
Several years ago, a pair of dark meteorites were discovered in the Sahara desert. They were nicknamed NWA 7034 and NWA 7533 – NWA being the acronym for Northwest Africa and the number that accompanies the order in which the meteorites were officially approved by the Meteoritical Society. The analysis showed that these Martian meteorites are extremely rare and contain mixtures of different rock fragments, some of which are 4.4 billion years old.
Given this great age, an international team led by Professor Takashi Mikouchi from the University of Tokyo recently purchased 50 grams of NWA 7533 for analysis.
‘I study minerals in Martian meteorites to understand how Mars formed and how its crust and mantle evolved. This is the first time I have investigated this particular meteorite, nicknamed Black Beauty because of its dark color, “Mikouchi said in a statement. ‘Our NWA 7533 samples underwent four different types of spectroscopic analysis, ways of detecting chemical fingerprints. The results led our team to draw some interesting conclusions.
Planetary scientists are well aware that there has been water on Mars for at least 3.7 billion years. But from the mineral composition of the meteorite, Mikouchi and her team deduced that water was likely present much earlier, about 4.4 billion years ago.
“The igneous clasts, or fragmented rocks, in the meteorite are formed from magma and are commonly caused by impacts and oxidation,” explained the professor. ‘This oxidation could have occurred if there was water present in the Martian crust 4.4 billion years ago during an impact that melted part of the crust. Our analysis also suggests that such an impact would have released a large amount of hydrogen, contributing to planetary warming at a time when Mars already had a dense insulating atmosphere of carbon dioxide.’
If there was water on Mars earlier than previously thought, that suggests that the water is possibly a natural byproduct of some process early in the planet’s formation. This finding could help researchers answer the question of where the water comes from, which in turn could affect theories about the origins of life and the exploration of life beyond Earth.
The full study has been published in the journal Science Advances.
Source: Tokyo University