Mars Volcanoes Still Active Today, Dark Deposits May Come from 50,000 Years Old Crater

For billions of years, scientists have known that Mars was volcanically active. Many people, on the other hand, assume that volcanic activity has long since stopped. According to a group of scientists, Mars was volcanically active in far more recent times.

According to CNet, researchers discovered evidence of a recent volcanic eruption, but they mean on a galactic timescale by recent. The data, according to experts, is thought to be from a blast that occurred within the last 50,000 years. Although that is still a long time, the discovery could have consequences for the quest for signs of microbial life on Mars.

(Photo: NASA/JPL/MSSS/The Murray Lab)
Recent explosive volcanic deposit around a fissure of the Cerberus Fossae system.

Researchers made the observations with the help of various instruments aboard the Mars Reconnaissance Orbiter (or MRO), which has been orbiting the planet since 2006. The images focused on an area known as Elysium Planitia (literally, the Heavenly Plains), specifically a region known as Cerberus Fossae, which is riddled with parallel cracks in the Martian crust.

The pre-print study, uploaded in arxriv.org, is titled "Evidence for Geologically Recent Explosive Volcanism in Elysium Planitia, Mars."

New and Different Kind of Volcanism

A team of planetary scientists examined one of these fractures with an unidentified 34-kilometer long fissure hundreds of meters deep. They called it "a dark deposit."

They found these lobes or wings of dark material that stretches for several kilometers along about half of its length on either side of the fissure. The surface around it is much lighter in color, most likely due to fine dust.

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They discovered the material is rich in pyroxene. According to Geology.com, pyroxene is a mineral typically found in volcanic flows, using other instruments onboard MRO.

They also discovered that the material has high thermal inertia, which means it takes a long time to warm up and cool down during the day and at night. The thermal inertia of plain old rocks is poor, so they heat and cool quickly. This suggests fluffier, grainier material, which is characteristic of volcanic eruptions.

There are about 20 million cubic meters or a cube about 270 meters across the total volume of dark material. Still, it's spread out over a large area and is probably a few hundred centimeters thick near the fissure (this was determined by looking at craters from impacts that happened after the material was deposited; they reveal how deep the material is).

The scientists believe this is most definitely a pyroclastic flow deposit. National Geographic said these are extremely hot gas and particle flows that can travel hundreds of kilometers per hour across the ground, burning and suffocating everything in their path (common on Earth when, for example, an explosive plume of ash collapses).

They acknowledge that it's possible that this isn't volcanic-related activity at all, but just dust and sand blew out of the fissure by the storm, but this is impossible. The wind blows from the southwest in this part of Mars, and the lobes can be seen extending to the SW and NE. The SW lobe is longer than the NE lobe (about 12 km vs. 6 km), but this is consistent with it being blown by wind after it formed; the fact that material is to the NE at all suggests this isn't a wind-driven feature.

How Old is the Crater?

When they tried to find out how old it was, things got really interesting. Examining craters is one way of doing so. Syfy.com explained that the longer a region is exposed, the more craters it accumulates. You can measure the age of the surface by counting craters and calculating their sizes... and what they find is that it may be 50-200 thousand years old.

Similar eruptions on Mars were discovered about 3 million years ago, according to researchers per Syfy.com. A significantly younger volcanic corruption can be seen in the 50,000-year-old period. The Mars InSight Lander is currently exploring the Elysium Planitia.

It is, however, about 1000 miles away from this specific deposit. Scientists also claim that if the deposit's source is volcanic in origin, it may indicate that Mars once had conditions that may have supported microbial life.