[meteorite-list] Mars Study Yields Clues to Possible Cradle of Life

[Ron Baalke]

https://www.jpl.nasa.gov/news/news.php?feature=6966

Mars Study Yields Clues to Possible Cradle of Life
Jet Propulsion Laboratory
October 6, 2017

Fast Facts:

* A long-gone sea on southern Mars once held nearly 10 times as much water 
as all of North America's Great Lakes combined, a recent report estimates.

* The report interprets data from NASA's Mars Reconnaissance Orbiter as 
evidence that hot springs pumped mineral-laden water directly into this 
ancient Martian sea.

* Undersea hydrothermal conditions on Mars may have existed about 3.7 
billion years ago; undersea hydrothermal conditions on Earth at about 
that same time are a strong candidate for where and when life on Earth 
began.

* The report adds an important type of wet ancient Martian environment 
to the diversity indicated by previous findings of evidence for rivers, 
lakes, deltas, seas, groundwater and hot springs.

The discovery of evidence for ancient sea-floor hydrothermal deposits 
on Mars identifies an area on the planet that may offer clues about the 
origin of life on Earth.

A recent international report examines observations by NASA's Mars Reconnaissance 
Orbiter (MRO) of massive deposits in a basin on southern Mars. The authors 
interpret the data as evidence that these deposits were formed by heated 
water from a volcanically active part of the planet's crust entering the 
bottom of a large sea long ago.

"Even if we never find evidence that there's been life on Mars, this site 
can tell us about the type of environment where life may have begun on 
Earth," said Paul Niles of NASA's Johnson Space Center, Houston. "Volcanic 
activity combined with standing water provided conditions that were likely 
similar to conditions that existed on Earth at about the same time -- 
when early life was evolving here."

Mars today has neither standing water nor volcanic activity. Researchers 
estimate an age of about 3.7 billion years for the Martian deposits attributed 
to seafloor hydrothermal activity. Undersea hydrothermal conditions on 
Earth at about that same time are a strong candidate for where and when 
life on Earth began. Earth still has such conditions, where many forms 
of life thrive on chemical energy extracted from rocks, without sunlight. 
But due to Earth's active crust, our planet holds little direct geological 
evidence preserved from the time when life began. The possibility of undersea 
hydrothermal activity inside icy moons such as Europa at Jupiter and Enceladus 
at Saturn feeds interest in them as destinations in the quest to find 
extraterrestrial life.

Observations by MRO's Compact Reconnaissance Spectrometer for Mars (CRISM) 
provided the data for identifying minerals in massive deposits within 
Mars' Eridania basin, which lies in a region with some of the Red Planet's 
most ancient exposed crust.

"This site gives us a compelling story for a deep, long-lived sea and 
a deep-sea hydrothermal environment," Niles said. "It is evocative of 
the deep-sea hydrothermal environments on Earth, similar to environments 
where life might be found on other worlds -- life that doesn't need a 
nice atmosphere or temperate surface, but just rocks, heat and water."

Niles co-authored the recent report in the journal Nature Communications 
with lead author Joseph Michalski, who began the analysis while at the 
Natural History Museum, London, andco-authors at the Planetary Science 
Institute in Tucson, Arizona, and the Natural History Museum.

The researchers estimate the ancient Eridania sea held about 50,000 cubic 
miles (210,000 cubic kilometers) of water. That is as much as all other 
lakes and seas on ancient Mars combined and about nine times more than 
the combined volume of all of North America's Great Lakes. The mix of 
minerals identified from the spectrometer data, including serpentine, 
talc and carbonate, and the shape and texture of the thick bedrock layers, 
led to identifying possible seafloor hydrothermal deposits. The area has 
lava flows that post-date the disappearance of the sea. The researchers 
cite these as evidence that this is an area of Mars' crust with a volcanic 
susceptibility that also could have produced effects earlier, when the 
sea was present.

The new work adds to the diversity of types of wet environments for which 
evidence exists on Mars, including rivers, lakes, deltas, seas, hot springs, 
groundwater, and volcanic eruptions beneath ice.

"Ancient, deep-water hydrothermal deposits in Eridania basin represent 
a new category of astrobiological target on Mars," the report states. 
It also says, "Eridania seafloor deposits are not only of interest for 
Mars exploration, they represent a window into early Earth." That is because 
the earliest evidence of life on Earth comes from seafloor deposits of 
similar origin and age, but the geological record of those early-Earth 
environments is poorly preserved.

The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, 
built and operates CRISM, one of six instruments with which MRO has been 
examining Mars since 2006. NASA's Jet Propulsion Laboratory, a division 
of Caltech in Pasadena, California, manages the project for the NASA Science 
Mission Directorate in Washington. Lockheed Martin Space Systems of Denver 
built the orbiter and supports its operations. For more about MRO, visit:

https://mars.nasa.gov/mro

News Media Contact
Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278
guy.webster at jpl.nasa.gov

Jenny Knotts
Johnson Space Center, Houston
281-483-5111
Norma.j.knotts at nasa.gov

Laurie Cantillo / Dwayne Brown
NASA Headquarters, Washington
202-358-1077 / 202-358-1726
laura.l.cantillo at nasa.gov / dwayne.c.brown at nasa.gov

2017-261