News / Science & Technology

Evidence of Martian Ocean Mounts

Comparison of exhumed delta in sedimentary rocks on Mars (left) with a modern delta on Earth (right). On the left, a shaded relief map shows elevated, branching, lobate features in Aeolis Dorsa, Mars, interpreted as resistant channel deposits that make up an ancient delta.
Comparison of exhumed delta in sedimentary rocks on Mars (left) with a modern delta on Earth (right). On the left, a shaded relief map shows elevated, branching, lobate features in Aeolis Dorsa, Mars, interpreted as resistant channel deposits that make up an ancient delta.

Related Articles

Water-Ice Clouds Activate Martian Atmosphere

There is more water vapor in the Martian atmosphere than in the upper layers of Earth's

Next Mars Rover Could Look for Signs of Past Life

NASA is thinking ahead to next rover it plans to send to Red Planet

Astronomer Finds New Moon Orbiting Neptune

An astronomer studying archived images taken by the Hubble Space Telescope finds a 14th moon orbiting the planet

Scientists Observe Solar System's Tail for First Time

Images from NASA's Interstellar Boundary Explorer spacecraft, known as IBEX, have allowed scientists to map out heliosphere's tail for first time
VOA News
Mars may have once had a vast ocean that covered as much as a third of the planet.

Researchers at the California Institute of Technology have found evidence of an ancient delta where a Martian river may have once emptied into the ocean.

"Scientists have long hypothesized that the northern lowlands of Mars are a dried-up ocean bottom, but no one yet has found the smoking gun," says Mike Lamb, an assistant professor of geology at Caltech and a coauthor of the paper describing the results. The paper was published online in the July 12 issue of the Journal of Geophysical Research.

Scientists say the evidence is not extensive enough to prove the ocean existed, but note that most of Mars’ northern hemisphere is flat and at a lower elevation than the southern hemisphere. It is similar to ocean basins found on Earth.

Using images from the Mars Reconnaissance Orbiter (MRO), Caltech scientists studied a 100-square-kilometer area on what might have been the former coastline. This area is located in a larger zone known as Aeolis Dorsa, which is covered in ridge-like features called inverted channels.

On Earth, inverted channels are the remnants of rivers or streams. After the river dries, silt and other finer materials erode away, leaving the larger rocks behind.

In the images analyzed by Caltech scientists, the inverted channels on Mars appear to fan out, which the scientists say could have been caused by three things: The channels could have been a drainage system down a mountain where they converged and created a larger river; it could have been caused by an alluvial water drainage fan; or the channels could be part of a river delta.

To determine which scenario they were looking at on Mars, scientists took pictures of the area from different points in the MRO’s orbit, creating stereo images. The camera on the MRO can distinguish changes in elevation at a resolution of one meter.

They determined that the water that once flowed through the channels was spreading out rather than converging, meaning they were part of an alluvial fan or delta. Researchers also noticed an “an abrupt increase in slope of the sedimentary beds near the downstream end of the channels,” which is commonly seen when a stream empties into a large body of water. 

Deltas have been observed on Mars before, but most are inside a geological boundary like a crater. The newly discovered delta showed no confining boundary.

"This is probably one of the most convincing pieces of evidence of a delta in an unconfined region — and a delta points to the existence of a large body of water in the northern hemisphere of Mars," said Roman DiBiase, a postdoctoral scholar at Caltech and lead author of the paper.

But scientists are quick to point out that there could be other explanations. For example, there could have been a confining boundary that later disappeared due to geological activity, but that would lead to the conclusion that the Martian surface was more geologically active than previously thought.

Further analysis of the hypothetical coastline will be needed before determining if there was a large ocean.

"In our work and that of others — including the Curiosity rover — scientists are finding a rich sedimentary record on Mars that is revealing its past environments, which include rain, flowing water, rivers, deltas, and potentially oceans," Lamb said. "Both the ancient environments on Mars and the planet's sedimentary archive of these environments are turning out to be surprisingly Earth-like."

You May Like

Video Video Claims to Show Shia Forces in Iraq Executing Sunni Boy

update While not yet independently confirmed, brutal killing already has gotten attention of Islamic State followers on social media More

After Six Years, Little Change for Niger Delta's Former Militants

Nigerians who laid down arms in exchange for government amnesty subsidies fear program may end with upcoming presidential elections More

Vietnam Pushes for More Educated Drivers to Curb Road Deaths

Transportation officials hope that making a greater effort to get drivers to learn the rules of the road will reduce fatal crashes More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
NASA Spacecraft Approaches a Dwarf Planeti
X
George Putic
March 04, 2015 8:51 PM
NASA’s Dawn spacecraft will make history on Friday, March 6, when it becomes the first man-made object to orbit a dwarf planet named Ceres. It is located in the asteroid belt between Mars and Jupiter, almost 500 million kilometers from Earth. Among other objectives, Dawn will try to examine two mysterious bright white spots detected on the planet’s surface. VOA’s George Putic has more.
Video

Video NASA Spacecraft Approaches a Dwarf Planet

NASA’s Dawn spacecraft will make history on Friday, March 6, when it becomes the first man-made object to orbit a dwarf planet named Ceres. It is located in the asteroid belt between Mars and Jupiter, almost 500 million kilometers from Earth. Among other objectives, Dawn will try to examine two mysterious bright white spots detected on the planet’s surface. VOA’s George Putic has more.
Video

Video Young Muslims Radicalized Online

Young Muslims are being radicalized ‘in their bedrooms’ through direct contact with Islamic State or ISIL fighters via the Internet, according to terror experts. There are growing concerns that authorities and Internet providers are not doing enough to counter online extremism - which analysts say is spread by a prolific network of online supporters around the world. Henry Ridgwell reports from London.
Video

Video African Americans Recall 1960's Fight For Voting Rights

U.S. President Barack Obama and thousands of people will gather in the small southern U.S. city of Selma, Alabama, Saturday, March 7th to commemorate the 50th anniversary of a historic voting rights march that became known as “Bloody Sunday." VOA’s Chris Simkins traveled to Alabama and introduces us to some of the foot soldiers of the voting rights struggles of the 1960’s.
Video

Video Positive Messaging Transforms Ethiopia's Image

Ethiopia was once known for famine and droughts. Now, headlines more often point to its fast-growing economy and its emergence as a regional peacemaker. How has Addis Ababa changed the narrative? VOA's Marthe van der Wolf reports.
Video

Video Cyber War Rages Between Iran, US

A newly published report indicates Iran and the United States have increased their cyber attacks on each other, even as their top diplomats are working toward an agreement to guarantee Iran does not develop a nuclear weapon and to free Iran from international sanctions. The development is part of a growing global trend. VOA’s Al Pessin reports from London.
Video

Video Answers Elude Families of MH370 Passengers

For the families on board Malaysia Airlines flight MH370, an airline official’s statement nearly one year ago that the plane had lost contact with air traffic control at 2:40 AM is the only thing that remains confirmed. William Ide reports.
Video

Video Land Disputes Arise Amid Uganda Oil Boom

Ugandan police say there has been a sharp increase in land disputes, with 10 new cases being reported each day. The claims come amid an oil boom as investors appear to be cashing in by selling parcels of land to multiple buyers. Meanwhile, the people who have been living on the land for decades are chased away, sometimes with a heavy hand. VOA's Serginho Roosblad reports.
Video

Video In Russia, Many Doubt Opposition Leader's Killer Will Be Found

The funeral has been held in Moscow for Boris Nemtsov, the opposition leader who was assassinated late Friday just meters from the Kremlin. Nemtsov joins a growing list of outspoken critics of Russia under the leadership of President Vladimir Putin who are believed to have been murdered for their work. VOA’s Daniel Schearf reports from Moscow.
Video

Video Simulated Astronauts Get Taste of Mars, in Hawaii

For generations, people have dreamed of traveling to Mars to explore Earth's closest planetary neighbor. VOA's Mike O'Sullivan reports that while space agencies like NASA are planning manned missions to the planet, some volunteers in Hawaii are learning how humans will cope with months in isolation on a Mars base.
Video

Video Destruction of Iraq Artifacts Shocks Archaeologists

The city of Mosul was once one of the most culturally rich and religiously diverse cities in Iraq. That tradition is under attack by members of the Islamic State who have made Mosul their capital city. The Mosul Museum is the latest target of the group’s campaign of terror and destruction, and is of grave concern to archaeologists around the world. VOA’s Kane Farabaugh reports.
Video

Video Smartphones May Help in Diagnosing HIV

Diagnosing infections such as HIV requires expensive clinical tests, making the procedure too costly for many poor patients or those living in remote areas. But a new technology called lab-on-a-chip may make the tests more accessible to many. VOA’s George Putic reports.
Video

Video Afghan Refugees Complain of Harassment in Pakistan

Afghan officials have expressed concern over reports of a crackdown on Afghan refugees in Pakistan following the Peshawar school attack in December. Reports of mass arrests and police harassment coupled with fear of an uncertain future are making life difficult for a population that fled its homeland to escape war. VOA’s Ayesha Tanzeem reports from Islamabad.

All About America

Circumventing Censorship

An Internet Primer for Healthy Web Habits

As surveillance and censoring technologies advance, so, too, do new tools for your computer or mobile device that help protect your privacy and break through Internet censorship.
More