new theory by authors at Caltech University and printed in Nature Geoscience, suggests the clay may have been formed by lava.
The team said the light signatures of the magma-formed Earth clays are very similar to some of the Martian clays, and samples brought to Earth via meteorites.
Ralph Milliken, a planetary scientist at Brown University who was not involved in the study, saw some merit to the idea.
Speaking to the LA Times, he said: 'It's certainly a different take on trying to explain the origin of some clay minerals on Mars.
'It does have some merit, and alternative hypotheses need to be considered fully.'
He added that some evidence disputed the idea, such as the tracks on Mars which appear to have been carved by flowing water, as well as signs of mineral deposits on Mars.
More knowledge is likely to be acquired by NASA's rover Curiosity, as it continues its investigation of the mountains and valleys of Mars.
Alain Meunier of France’s Universite de Poitiers and a team studied clay minerals at Mururoa atoll in French Polynesia that seem similar to martian examples, and showed they were formed from precipitation of lava.
The same process has also occurred at other locations on Earth, including the Parana basin in Brazil, said the study in Nature Geoscience.
“To crystallise, clays need water but not necessarily liquid water. In other words, clays are not exclusively typical of soils or altered rocks; they may crystallise also directly from magmas,” Meunier told AFP by email.
“Magmatic clays have no climatic significance. Consequently, they cannot be used to prove that the planet was habitable or not during its early history.”
If the theory is correct, it “would imply that early Mars may not have been as habitable as previously thought at the time when Earth’s life was taking hold,” University of Colorado geologist Brian Hynek wrote in a comment.
No comments:
Post a Comment