Washington, Sept 20 : The discovery of young Martian clays, rich in minerals and formed by water, suggests the planet could have supported life relatively recently in its history, NASA scientists say.

The minerals were found inside two small depressions in a region of the planet known as Noctis Labyrinthus.

"We discovered locations at Noctis Labyrinthus that show many kinds of minerals that formed by water activity," said lead author Catherine Weitz, senior scientist at the Planetary Science Institute.

"The clays we found, called iron/magnesium (Fe/Mg)-smectites, are much younger at Noctis Labyrinthus relative to those found in the ancient rocks on Mars, which indicates a different water environment in these depressions relative to what was happening elsewhere on Mars," she added.

Smectites are a specific type of clay mineral that expands and contracts with adsorbed water. They contain silica, plus aluminum, iron or magnesium in their structures. They form by the alteration of other silicate minerals in the presence of non-acidic water.

Weitz and her co-authors studied approximately 300 meters of vertically exposed layered rocks within two 30 to 40-km wide depressions, called troughs, near the western end of the Valles Marineris canyon system.

They used high-resolution images and hyperspectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on the Mars Reconnaissance Orbiter (MRO) spacecraft, and combined it with digital terrain models to determine elevations and view geometric relationships between units.

The team was then able to map hydrated minerals and understand how the water chemistry varied with time within each trough, said Weitz.

They found that each trough probably experienced multiple episodes where water partially filled in low-lying regions and deposited minerals.

As each trough continued to enlarge and experience collapse over time, older minerals became buried and separated, followed by deposition of younger minerals, then finally erosion to re-expose buried units.

The observed minerals indicate water varied in pH levels over time, in one trough from acidic to neutral, and in the other trough from neutral to acidic and back to neutral.

"These clays formed from persistent water in neutral to basic conditions around 2 to 3 billion years ago, indicating these two troughs are unique and could have been a more habitable region on Mars at a time when drier conditions dominated the surface," said co-author Janice Bishop from the SETI Institute and NASA Ames Research Center.

The findings are published in the journal Geology. (ANI)