New look at minerals, could change the way we search for life

For the first time, scientists have created an ordered catalog where we can find all the information about minerals. This collection of mineral origin stories suggests that the Earth may have harbored life earlier than previously thought.

The reason comes from quantifying water as the most variable component in geology, and that could change the way researchers look for signs of life and water on other planets.

Calcite can form in 17 different ways, more than almost any other mineral. This calcite, formed in a cave, has a special shape due to the changing water levels.

"This is going to be a 'big bang' in the research world," said Robert Hazen, a mineralogist and biologist at the Carnegie Institution for Science in Washington, DC.

For more than 100 years, scientists have primarily identified minerals to answer the "what is it" question, often focusing on their structure and chemical composition. However, it inadvertently creates an incomplete picture and has many gaps in knowledge.

For example, although all diamonds are a crystalline carbon, three different diamonds can tell three different stories, Hazen said. One may have formed 5 billion years ago in a distant star, another may have been born in a meteorite collision, and the other may have been formed by heat and high pressure deep below the Earth's crust.

Diamonds have the same carbon structure, but they can form in different ways. This particular gemstone is often sourced deep within the Earth.

So Hazen and his colleagues identified a different approach to mineral classification. This approach will focus on "how" they form and think about minerals as things that evolved from the history of life. He and his team then published their findings on July 1 in the journal American Mineralogist. Researchers have now identified 57 ways minerals form, from condensing in space and between stars to forming in bat droppings.

The information in the catalog is not new, but in the past it was often scattered among thousands of scientific articles and was not organized in a systematic way. Hazen says the "boldness" of their work is in taking it and putting it all together (more than 5,600 known minerals). That makes the catalog a one-stop-shop for those looking to use the mineral to dig into the past.

The compilation also allowed the team to take a step back and think about mineral evolution from a broader perspective. One of the new studies shows that more than half of all known minerals formed in ways that would have been possible on Earth in the early days.

Of all the geological environments that scientists consider potential for the initiation of life on Earth, most may have existed as early as 4.3 billion years ago. Thus, life may have started almost immediately after the Earth formed, or at least earlier than scientists had thought.

"That would be a very poignant implication - that the potential for life was ignited right away," said Zachary Adam, a paleontologist at the University of Wisconsin-Madison who was not involved in the new studies. from the very beginning of a planet".

However, Frances Westall, a biogeographer at the Center for Molecular Biophysics in Orléans, France, says the exact moment when conditions are ripe for life is based on "iffy" models. She says scientists need more data before they can say for sure. But, she said, "this study and its implications are amazing".

The new results also show how essential water is to the creation of most minerals on Earth. The team reports that about 80 percent of known minerals require water (H20) in their formation.

Some minerals would not have formed in certain ways without the influence of life. Photosynthetic bacteria helped bring about the oxygen-rich conditions needed for this azurite (left), while the opal ammonification (right) was created by the mineral opal, where an ammonium shell used to be.

In a word, this means that if researchers see water on a planet like Mars, they can guess that it has a rich mineral ecosystem. Scientists can identify what minerals are present on the Red Planet and then use this new catalog to study back and find its environment in the past.

"I think we can do more than that. And it's just a matter of time and effort right now," said Shaunna Morrison, a mineralogist at the Carnegie Institution and co-author of the new studies. to research".