Not long after NASA’s Opportunity rover descended on Mars back in 2004 it discovered small rocks that have been called “blueberries,” and scientists are still working hard to learn more about these strange geological formations. While these rocks do indeed resemble blueberries, determining their makeup is something that has continued to confound scientists.
To learn more about these blueberries on Mars, scientists have spent many years examining similar rocks found here on Earth and have used chemistry to not only try to understand what the rocks are made of, but to also understand how the landscape of Mars may have once appeared, as Live Science reports.
Briony Horgan, who is a planetary scientist at Purdue University in Indiana, has explained that regardless of the chemistry of these tiny rocks, it is clear that at one point in time vast amounts of water must have flowed over them.
“No matter what the exact chemistry of these spherules was to start, the fact that they’re there tells us that a lot of liquid water moved through these rocks over time.”
Horgan also noted that once scientists discover how the blueberry rocks on Mars were created, they may also be able to ascertain what different kinds of life may have thrived on the Red Planet in its early days. To try and discover their chemical composition, scientists have examined other rocks which resemble the Martian rocks in Mongolia and Utah. However, the rocks in these two locations aren’t exactly the same as they are much greater in size. As Horgan stated, “They’re all blobbed together. They’re different sizes.”
But despite the rocks in Utah and Mongolia not being exactly the same size as their Martian counterparts, it is much easier for scientists to travel to these locations than to travel to Mars to physically examine the actual specimens there. What scientists have discovered so far is that the cores of these rocks were created out of iron-rich calcite, with the rocks forming around this mineral.
According to Hidekazu Yoshida of Nagoya University and Hitoshi Hasegawa of Kochi University in Japan, scientists were absolutely thrilled to discover part of the chemical composition of these mysterious rocks.
“That moment of discovery, it was very exciting.”
After conducting chemical modeling and examining the blueberry rocks, scientists feel certain that acidic water which was also very rich in iron may have flooded over the first deposits of calcite on Mars. However, the real Martian rocks at this point are made entirely of hematite and no longer contain any calcite like the rocks on Earth do. Yet this may simply mean that prolonged periods of water rushing over them on Mars may have alleviated any remaining calcite.
But the mystery of these strange rocks continues to persist. Planetary geologist Steve Ruff from Arizona State University has stated, “My sense of what we know about the area of the hematite that we can map from orbit is it’s not a huge area, covering less than 1 percent of Mars’ surface.”
Ruff also has concerns that the rocks that are being studied on Earth may be too different from the Martian ones, yet believes that these kinds of studies are still extremely useful.
“I’m intrigued by this idea. The formation of these little concretions on Earth and certainly on Mars has always been a bit of a mystery, and there’s multiple ideas about how you form these things.”
The new study on the many mysteries of the rocks on Mars known as blueberries has been published in Science Advances.