Martian clay could help reveal environmental conditions on early Earth
Researchers from the University of Hawaiʻi at Mānoa NASA Astrobiology Institute (UHNAI) have discovered high concentrations of boron in a Martian meteorite. When present in its oxidized form (borate), boron may have played a key role in the formation of RNA, one of the building blocks for life. The work was published on June 6 in PLOS One.
Borates may have been important for the origin of life on Earth because they can stabilize ribose, a crucial component of RNA. In early life, RNA is thought to have been the informational precursor to DNA, said James Stephenson, an evolutionary biologist and UHNAI postdoctoral fellow. Furthermore, RNA may have been the first molecule to store information and pass it on to the next generation, a mechanism crucial for evolution.
On Earth, borate-enriched salt, sediment and clay deposits are relatively common, but such deposits had never previously been found on an extraterrestrial body. This new research suggests that when life was getting started on Earth, borate could also have been concentrated in deposits on Mars.
The significance goes beyond an interest in the red planet. “Earth and Mars used to have much more in common than they do today. Over time, Mars has lost a lot of its atmosphere and surface water, but ancient meteorites preserve delicate clays from wetter periods in Mars’ history,” said Lydia Hallis, lead author on the paper along with Stephenson and a cosmochemist and UHNAI postdoctoral fellow. “The Martian clay we studied is thought to be up to 700 million years old. The recycling of the Earth’s crust via plate tectonics has left no evidence of clays this old on our planet; hence, Martian clays could provide essential information regarding environmental conditions on the early Earth.”
The presence of ancient borate-enriched clays on Mars implies that these clays may also have been present on the early Earth. Borate-enriched clays such as the ones studied here may have represented chemical havens in which one of life’s key molecular building blocks could form.
For more, read the UH Mānoa news release.