A hundred million years ago, a sea creature called an Ammonnite died and its hard carbonate shell settled into the sea as a biomineral. The carbonate was replaced with silicates.
The impact of Earth's geology on life can be seen, with organisms adapting to environments as different as deserts, mountains, forests and oceans. Life's impact on geology can be missed. That omission has been corrected by a new survey of our planet's minerals. Evidence shows that half of all mineral diversity is the result of living things. It is a discovery that could provide valuable insights to scientists who are trying to piece together Earth's geological history. In a pair of papers published today in American Mineralogist, Robert Hazen and his team outline a new system for classifying minerals, one that places importance on how minerals form, not just how they look. They acknowledge how Earth's geological development and the evolution of life influence each other. More than 10,500 different types of minerals are recognized by their new Taxonomy. The International Mineralogical Association focuses on a mineral's crystal structure and chemical makeup. Hazen is a mineralogist at the Carnegie Institute for Science in Washington, D.C. He started digging into the literature in 2008 to find out how the minerals formed. Morrison said the project was a monster to try to tackle. Many mineral species came from different processes. Pyrite is also known as fool's gold and is a type of crystal. There are 21 fundamentally different ways in which pyrite forms. Over millions of years, iron deposits heat up in the underground and cause the formation of some pyrite crystals. Some form as a result of the breakdown of organic matter on the seafloor. Others are associated with coal mines.
Under a wide range of temperature and hydration conditions, there are three different kinds of pyrite, which can be formed in 21 different ways.
Hazen said that each one of those kinds of pyrite tells a different story about our planet, its origin, and how it has changed over time. Hazen and Morrison define a combination of the mineral species with its mechanism of origin as "kind" minerals. They used machine learning analysis to identify 10,556 different types of minerals. All known minerals were created by 57 separate processes. The processes included weathering, chemical precipitations, metamorphic transformation inside the mantle, lightning strikes, radiation, oxidation, and even condensations in space before the planet formed. Water is the biggest factor in the diversity of minerals on the planet.
There are blue-green formations of malachite in copper deposits. They arose after life raised atmospheric oxygen levels.
They found that one-third of all mineral kinds form exclusively as parts of living things, such as bits of bones, teeth, coral and kidneys stones, which are all rich in mineral content. germanium compounds are found in industrial coal fires and are shaped by life's activity. Half of all minerals have life's fingerprints on them. Nita Sahai is a biomineralization specialist at the University of Akron in Ohio who was not involved in the new research. The boundary between animals, vegetables, and minerals is not static. The human body has 2% minerals by weight, most of it locked away in the scaffolding that protects our teeth and bones. Morrison and Hazen's new Taxonomy put a nice systematization on it and made it more accessible to a broader community.
Some scientists will be happy with the new Mineral Taxonomy. Sarah Carmichael is a mineralogy researcher at Appalachian State University. Carlos Gray Santana is a philosopher of science at the University of Utah and he is standing by the IMA system. He said that the IMA taxonomy still works well in chemistry, mining and engineering because it was developed for those purposes. It serves our needs well. Scientists need to do things like space exploration. One implication of Hazen and Morrison's findings is that our watery, living planet is more rich in minerals than other rocky bodies in the solar system. Hazen said there were many minerals that couldn't be formed on Mars. It doesn't have penguins pooping on clay minerals, it doesn't have bats in caves, and it doesn't have cacti that are rotting. Hazen and Morrison hope that one day they will be able to use their taxonomy to look for signs of life on other planets or moons. Researchers can use the new mineralogical framework to look at features like grain size and structure defects to see if it could have been produced by an ancient microbe. Hazen thinks that the new taxonomy might be able to detect life on planets outside our solar system. Light from exoplanets can be analyzed to determine the chemical composition of their atmospheres, based on the measurable oxygen content, the presence or absence of water Vapor, relative carbon concentrations and other data. The methodology may be pushing it too far since you won't go to those planets and collect minerals to confirm the results. He sees Hazen and Morrison's Taxonomy as an important source of insights for studies of extraterrestrial minerals found on our moon and Mars. Morrison said, "We are understanding not just our planet, but also our entire solar system, and possibly solar systems beyond." That is amazing.
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