Mineral evolution

The last billion years have witnessed a particularly dramatic increase in mineralogical diversity, primarily as a consequence of atmospheric oxygenation. To understand this Neoproterozoic and Phanerozoic acceleration in mineral evolution we must thus address another emergent chemical event - the origin of life. 

The Redpath Museum has a few meteorites, although you can easily miss them. They re just tiny black rocks, some speckled, a few of bulbous metal, but none is very colorful. Geology was a lot simpler 5 billion years ago. In his paper describing mineral evolution, Hazen says the earliest meteorites have only 60 different minerals, about 20 of these in grains too small to see. The planetary disk and intense solar radiation worked like a blender on high speed, smoothly mixing the elements into hard, dark chunks of rock, rich in Hazen s Big Six elements. The other 77 elements were occasional impurities smoothly dispersed throughout. 

If not for the larger size and wetter composition of Earth, our planet would look like those, a gray swirl of light and dark rocks, pitted with asteroid craters and devoid of life or even movement. Mercury and the moon are time machines to an alternate past in which Earth did not have the chemicals that it needed to continue its mineral evolution. 

Earth has very old rounded pebbles about the same age, showing that our oceans also formed early. Hazen s Mineral Evolution essay describes rounded pebbles of fool s gold pyrite and a uranium rock that will react quickly with even a hint of oxygen. Because all the oxygen was locked up in rocks, these pebbles persisted long enough to tumble through water, and eroded rather than corroded. 

In Mineral Evolution (2008), Hazen and coworkers estimated that the processes described in this chapter—granite formation, plate tectonics, and carbonate deposition—added about 1,000 new mineral species to our rocks. Most involve the action of water, so that means hquid oceans tripled the number of different minerals on this planet from 500 to 1,500. 

The Earth changed with life, in a process geologist Robert Hazen describes as coevolution. Earlier in this story, Hazen described how water formed a thousand different minerals on the Earth s surface. At this point oxygen extended the process of mineral evolution, multiplying the different minerals even more We suggest that fully two-thirds of the approximately forty-five hundred known mineral species could not have formed prior to the GOE, and that most of Earth s rich mineral diversity probably could not occur on a non-living world (p. 177). 

Copper was also brought out into the ocean by water and oxygen working together. Hazen notes in Mineral Evolution that 256 of 321 copper minerals were formed by the action of water, which means they were laid down by rain, erosion, and sedimentation after copper was released by oxygen. 

Hazen, Robert Geologist who wrote The Story of Earth (20i2), which describes his theory of mineral evolution. 

Robert Hazen has assembledageological theory called mineral evolution,... R.M. Hazen et al. Mineral evolution. 2008. Amer Mineral. 93(ii-i2), p. i693. DOl 10.2138/ am. 2008.2955. 

This steam-driven motion added about 250 more minerals to the early earth,. .. See Hazen, Mineral evolution. ... 

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