Mars Study Yields Clues to Possible Cradle of Life

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@jpl.nasa.gov

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

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

2017-261

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