Insulating crust kept cryomagma liquid for millions of years on nearby dwarf planet

February 12, 2019

A recent NASA mission to the dwarf planet Ceres found brilliant, white spots of salts on its surface. New research led by The University of Texas at Austin in partnership with NASA's Jet Propulsion Laboratory (JPL) delved into the factors that influenced the volcanic activity that formed the distinctive spots and that could play a key role in mixing the ingredients for life on other worlds.

The volcanoes on Ceres are cryovolcanoes, a type of volcano that forms on planetary bodies with icy shells and that moves salty water known as cryomagma from underground reservoirs to the surface. Scientists think that cryovolcanoes on Jupiter's icy moon Europa could help foster chemical mixing that could make complex molecules needed for life. Learning more about how these volcanoes work on Ceres--which is a simpler geological environment than Europa--could help scientists get a handle on the primary forces that drive their activity.

"Cryovolcanism looks to be a really important system as we look for life," said lead author Marc Hesse, an associate professor at the UT Jackson School of Geosciences. "So we're trying to understand these ice shells and how they behave."

The final version of the research was published online on Feb.8 in the journal Geophysical Research Letters. The research was co-authored by Julie Castillo-Rogez, a planetary scientist at NASA's JPL.

At 585 miles across, Ceres is the largest planetary body in the asteroid belt between Mars and Jupiter. Forged billions of years ago from rock and ice and far enough from the influence of other planets, scientists had thought that Ceres' days of active geology had come to close. But the NASA Dawn mission changed that view when the space probe sent back pictures of bright, white spots at the bottom of impact craters. The spots turned out to be the remnants of cryomagma.

The location of the spots at or near the center of crater basins suggests that the heat and energy generated by asteroid impacts could jumpstart geology on Ceres, creating reservoirs of cryomagma that were then brought to the surface by conduits such as fractures.

The new research looked specifically at the deposits on the floor of the 90-mile-wide crater Occator, which was formed about 20 million years ago. However, the deposits here are as young as 4 million years old, indicating a relatively recent formation geologically speaking with respect to the crater itself. Earlier research conducted by other scientists found that the conditions on Ceres wouldn't allow for the cryomagma generated by the Occator impact to exist for more than about 400,000 years.

The age discrepancy between salt deposits and impact timing raises a question: How could a reservoir of melt stay in a liquid state for millions of years after impact on an otherwise geologically stagnant world?

In their new paper, Hesse and Castillo-Rogez were able to significantly extend the life of the cryomagma by including more up-to-date details on Ceres' crustal chemistry and physics.

"It's difficult to maintain liquid so close to the surface," said Castillo-Rogez. "But our new model includes materials inside the crust that tend to act as insulators consistent with the results from the Dawn observations."

The new calculations indicate that the cryomagma of Occator could last up to 10 million years--a value that doesn't close the time gap completely, but that indicates that the additional data helps make a more realistic cooling timeline.

"Now that we're accounting for all these negative feedbacks on cooling--the fact that you release latent heat, the fact that as you warm up the crust it becomes less conductive--you can begin to argue that if the ages are just off by a few million years you might get it," Hesse said.

Jennifer Scully, a planetary geologist at NASA's JPL who studies Ceres but was not involved with the study, said that the findings are a great contribution toward unpacking the geologic history of an alien world.

"They used more up-to-date data to create their model," said Scully. "This will help in the future to see if all of the material involved in the observed deposits can be explained by the impact, or does this require a connection to a deeper source of material. It's a great step in the right direction of answering that question."
-end-
The National Science Foundation and NASA funded the research.

University of Texas at Austin

Related Volcanic Activity Articles from Brightsurf:

Volcanic eruptions have more effect in summer
Modeling shows that volcanic eruptions can cause changes in global climate, if the timing is right.

Piecing together the Alaska coastline's fractured volcanic activity
Among seismologists, the geology of Alaska's earthquake- and volcano-rich coast from the Aleutian Islands to the southeast is fascinating, but not well understood.

ALMA shows volcanic impact on Io's atmosphere
New radio images from ALMA show for the first time the direct effect of volcanic activity on the atmosphere of Jupiter's moon Io.

Indian monsoon can be predicted better after volcanic eruptions
Large volcanic eruptions can help to forecast the monsoon over India - the seasonal rainfall that is key for the country's agriculture and thus for feeding one billion people.

Photos may improve understanding of volcanic processes
The shape of volcanoes and their craters provide critical information on their formation and eruptive history.

Volcanic activity and changes in Earth's mantle were key to rise of atmospheric oxygen
Evidence from rocks billions of years old suggest that volcanoes played a key role in the rise of oxygen in the atmosphere of the early Earth.

Volcanic eruptions reduce global rainfall
POSTECH Professor Seung-Ki Min's joint research team identifies the mechanism behind the reduction in precipitation after volcanic eruptions.

A new tool to predict volcanic eruptions
Earth's atmosphere is made up of 78% nitrogen and 21% oxygen, a mixture that is unique in the solar system.

Oral traditions and volcanic eruptions in Australia
In Australia, the onset of human occupation (about 65,000 years?) and dispersion across the continent are the subjects of intense debate and are critical to understanding global human migration routes.

Volcanic ash sparks a new discovery
Imagine you're getting ready to fly to your favorite vacation destination when suddenly a volcano erupts, sending massive amounts of volcanic ash into the atmosphere, and forcing the cancellation of your flight.

Read More: Volcanic Activity News and Volcanic Activity Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.