Most volcanic activity on Mercury stopped about 3.5 billion years ago

Date:

Share post:

New research from North Carolina State University finds that major volcanic activity on the planet Mercury most likely ended about 3.5 billion years ago. These findings add insight into the geological evolution of Mercury in particular, and what happens when rocky planets cool and contract in general.

Most volcanic activity on Mercury stopped about 3.5 billion years ago
Enhanced color image of Mercury. The bright, circular deposit in the upper center of the image is an enormous 
effusive volcanic deposit, situated within the largest impact crater on the planet, the Caloris basin 
[Credit: NASA/Johns Hopkins Applied Physics Lab/Carnegie Institution of Washington]

There are two types of volcanic activity: effusive and explosive. Explosive volcanism is often a violent event that results in large ash and debris eruptions, such as the Mount Saint Helens eruption in 1980. Effusive volcanism refers to widespread lava flows that slowly pour out over the landscape — believed to be a key process by which planets form their crusts.

Determining the ages of effusive volcanic deposits can give researchers a handle on a planet’s geological history. For example, effusive volcanism was active a few hundred million years ago on Venus, a few million years ago on Mars, and it still takes place on Earth today. Until now, the duration of effusive volcanic activity on Mercury, made of the same materials as these other planets, had not been known.

NC State assistant professor and planetary geologist Paul Byrne and colleagues determined when the bulk of Mercury’s crust-forming volcanism ended by using photographs of the surface imaged by NASA’s MESSENGER mission. Because there are no physical samples from the planet that could be used for radiometric dating, the researchers used crater size-frequency analysis, in which the number and size of craters on the planet’s surface are placed into established mathematical models, to calculate absolute ages for effusive volcanic deposits on Mercury.

According to their results, major volcanism on Mercury stopped at around 3.5 billion years ago, in stark contrast to the volcanic ages found for Venus, Mars and Earth.

“There is a huge geological difference between Mercury and Earth, Mars or Venus,” Byrne says. “Mercury has a much smaller mantle, where radioactive decay produces heat, than those other planets, and so it lost its heat much earlier. As a result, Mercury began to contract, and the crust essentially sealed off any conduits by which magma could reach the surface.

“These new results validate 40-year-old predictions about global cooling and contraction shutting off volcanism,” Byrne continues. “Now that we can account for observations of the volcanic and tectonic properties of Mercury, we have a consistent story for its geological formation and evolution, as well as new insight into what happens when planetary bodies cool and contract.”

The research appears in Geophysical Research Letters.

Author: Tracey Peake | Source: North Carolina State University [August 05, 2016]

ADVERTISEMENT

spot_img

Related articles

Hoard of silver medieval coins found in Greece

Archaeologists in Greece have found over fifty Venetian silver coins dating to the 14th century AD, hidden in...

Dinosaur-killing impact acidified oceans

The space rock that smashed into Earth 65 million years ago, famously wiping out the dinosaurs, unleashed acid...

Unlocking the mystery behind Saturn’s moonlets

Research by Loughborough University physicists casts new light on Saturn's moonlets -- and could help solve some of...

Artefacts of Hagia Sophia on display at Trabzon Museum

Thirty-three historic artifacts in the garden of the Hagia Sophia in the Black Sea province of Trabzon have...

Fossil discovery sheds new light on evolutionary history of higher primates

An international team of researchers has announced the discovery of Afrasia djijidae, a new fossil primate from Myanmar...

Glimpse into the future of acidic oceans shows ecosystems transformed

Ocean acidification may create an impact similar to extinction on marine ecosystems, according to a study released today...

Peru's Lady of Cao mummy died during childbirth

A recent study suggests that the Lady of Cao, a spectacularly well-preserved mummy found in northern Peru in...

800-year-old shipwreck found off Sweden’s coast

An 800-year-old shipwreck has been found by divers off the south coast of Sweden, prompting speculation it may...