Major Volcanic Activities in Mercury Ended Nearly 3.5 Billion Years Ago
A new study from North Carolina State University revealed that all major volcanic activities in Mercury were most likely stopped about 3.5 billion years ago, giving an additional insight in the evolution of Mercury and the result of cooling and contraction to rocky planets.
"These new results validate 40-year-old predictions about global cooling and contraction shutting off volcanism," said Paul Byrne, an assistant professor and planetary geologist at NC State and lead author of the study, in a statement. "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 study, published in the journal Geophysical Research Letters, suggests a stark contrast to the volcanic ages found for Venus, Mars and Earth. Major volcanic activities were active on Venus a few hundred million years ago, while volcanism in Mars was active a few million years ago. However, volcanism on Earth is still active up to this day.
For the study, the researchers determined the crater-size frequency distributions of nine next-largest deposits that were interpreted as volcanoes. In the analysis, researchers placed the number and size of craters in the planet's surface into established mathematical models, calculating absolute ages of effusive volcanic deposits in Mercury.
The results showed that major volcanism in Mercury halted around 3.5 billion years ago. Researchers believe that the geological attributes of Mercury played a role in stopping the volcanic activities in the planet.
As opposed to Mars, Venus and Earth, Mercury has a much smaller mantle where radioactive decay produces heat, making it lost its heat earlier than other inner planets. This resulted in the contraction of the planet that lead to the crust sealing off conduits by which magma could reach the surface.
The study was funded by NASA's MESSENGER mission and was co-authored by researchers from Carnegie Institution of Washington, Mount Holyoke College, the University of Georgia, Southwest Research Institute and Brown University.