The origin of minerals

A 15-year study, led by the Carnegie Institution of Science in the United States, details the origins and diversity of all known minerals on Earth, a landmark work that will help reconstruct the history of life on Earth. to guide the search for new minerals and deposits, to predict the possible characteristics of future life and to contribute to the search for habitable planets and extraterrestrial life.

Robert Hazen and Shaunna Morrison detail a novel approach to group minerals into species (types) by their affinity or separate minerals into new species based on when and how they originated.

Once the genesis of minerals is taken into account, the number of “mineral species” amounts to more than 10,500, a figure that is 75% higher than that of the approximately 6,000 mineral species recognized by the International Mineralogical Association (IMA). ) based solely on crystal structure and chemical composition.

This novel work radically changes the way of seeing the diversity of minerals on the planet, as Hazen emphasizes. And it allows you to see things from a much broader and more revealing perspective. For example, more than 80% of the minerals on Earth have the intervention of water. This is therefore a substance of fundamental importance for the mineral diversity on this planet. This is also one of the main reasons why the Moon and Mercury, and even Mars, have far fewer mineral species than Earth.

The research also shows the global role of biology in mineralogy in a much more eloquent way. A third of the minerals on Earth could not have been formed without biological materials such as shells, bones and microbes, or without the vital indirect role of biology, such as creating an oxygen-rich atmosphere that gave rise to some 2,000 minerals. that could not have been formed otherwise.

Example of a mineral formed with the help of biological processes. (Photo: ARKENSTONE/Rob Lavinsky)

The study indicates that nature created 40% of the Earth’s mineral species in more than one way; for example, both abiotically and with the help of cells. And in several cases he used more than 15 different recipes to produce the same crystal structure and chemical composition.

The most extreme example of the latter is the 21 different forms of processing that nature has used over the last 4.5 billion years to create pyrite. Pyrite forms at high and low temperatures, with and without water, with the help of microbes, and in environments where life plays no role.

Among the conclusions of the investigation, the following also stand out:

-Rare elements play a disproportionately large role in Earth’s mineral diversity. Just 41 elements, which together make up less than 5 parts per million of the Earth’s crust, are essential components in some 2,400 (more than 42%) of the Earth’s minerals. These 41 elements include arsenic, cadmium, gold, mercury, silver, titanium, tin, uranium and tungsten.

-Much of the Earth’s mineral diversity was established in the planet’s first 250 million years.

-Some 296 known minerals are believed to predate the Earth itself. Of such minerals, 97 are only known from meteorites (with the age of some individual mineral grains estimated at 7 billion years, that is, several billion years before the formation of our solar system).

a-More than 600 minerals are the indirect result of human activities, including more than 500 minerals caused by mining, with 234 of them formed by fires in coal mines.

Hazen and Morrison present the results of their research in the academic journal American Mineralogist, under the title “On the paragenetic modes of minerals: A mineral evolution perspective”. (Font: NCYT by Amazings)