Believe it or not, pieces of Mars have been raining down on Earth for eons. Powerful impacts on the Red Planet’s surface have launched debris into space, some of which eventually find its way to our planet as meteorites. Scientists have now taken a significant leap forward in understanding these Martian visitors. Researchers at the University of Alberta have pinpointed the origins of 200 Martian meteorites to five impact craters within two volcanic regions on Mars known as Tharsis and Elysium. This discovery opens a new window into Mars’ geological history, allowing scientists to better understand its volcanic activity and the timing of major events throughout its past.
While meteorites fall to Earth constantly, identifying their source can be tricky. However, scientists became suspicious of a group of meteorites with volcanic origins and ages of 1.3 billion years, making Mars a likely candidate. Confirmation came when NASA’s Viking landers compared the composition of Mars’ atmosphere with trapped gases in these rocks.
Previously, identifying the specific locations on Mars from which these meteorites originated was challenging. Spectral matching, a technique used to compare the composition of materials, was hindered by factors like terrain variability and dust cover. This new research overcame these challenges by combining high-resolution simulations of impacts on a Mars-like planet with analysis of the meteorites themselves.
The team’s model allowed them to determine the impact events’ peak shock pressures and the duration the rocks were exposed to these pressures. This information, gleaned from the meteorites’ unique mineral changes, impact glass, and fracture patterns, helped the researchers estimate the size of the impact craters that launched them and how deeply the rocks were buried before the impact.
This research offers a remarkable opportunity to reconstruct Mars’ volcanic stratigraphy and understand the timing of volcanic events, the different sources of Martian magma, and the rate at which craters formed during the Amazonian period, a time of reduced meteorite bombardment approximately 3 billion years ago. By tracing these Martian meteorites back to their specific origins, scientists are essentially taking a giant leap closer to physically exploring the Red Planet itself.
