14 DAY TRIAL // A group of scientists with the Carnegie Institution for Science determined in a new study that the early Earth did not feature the vast diversity of mineral species it boasts today. In fact, only less than 8 percent of current minerals existed on the planet 550 million years after it formed.
This finding is very important because biologists attribute minerals with a very important role in promoting the development of life on our planet. These materials are believed to have provided a shelter for the earliest building blocks of life to endure the harsh planetary conditions of the time.
In a paper published in the latest issue of the American Journal of Science, researchers say minerals may have facilitated the emergence of the first molecules necessary for life and provided the necessary metabolic energy for these early structures to develop later on.
However, these studies have always assumed that Earth's mineral diversity was similar to the one we see today. During the Hadean Eon – the planet's first 550 million years of life – only around 420 mineral species existed, as opposed to the nearly 5,000 we can detect today, the new paper shows.
For this research, CIW scientists created a list of all mineral species that were possible during the Hadean Eon, based on the conditions available on Earth at the time. The research effort was led by research scientist Robert Hazen, from the CIT Geophysical Laboratory.
The relatively-low number of mineral species this study predicts is largely “a consequence of the limited ways that minerals might have formed prior to 4 billion years ago,” explains Hazen, who also holds an appointment as the Clarence Robinson professor of Earth science at George Mason University.
“Most of the 420 minerals of the Hadean Eon formed from magma – molten rock that slowly crystallized at or near Earth’s surface – as well as the alteration of those minerals when exposed to hot water,” he goes on to say.
Hazen says that, most likely, many of the models explaining the origins of life will not have to be changed due to the new study, though some may require adjustments. The majority of minerals believed to have played a critical role in the development of life were still found to have existed during the Hadean Eon.
What the team found is that slow-forming minerals such as those containing lithium, beryllium or molybdenum, took at least one billion years to develop, so they were likely not available early on.
Hazen and his group were funded by the US National Science Foundation (NSF), the NASA Astrobiology Institute, the Deep Carbon Observatory, and the Carnegie Institution for Science.