What does a prehistoric culture have in common with platinum? According to a new study, platinum may reveal why the Clovis people, a prehistoric Native American culture that existed 12-13,000 years ago, suddenly disappeared.
The research, conducted by University of South Carolina archaeologists and described on the SC website, suggests the civilization was wiped out by an asteroid. The evidence is widespread platinum, an element associated with asteroids or comets, at archaeological sites across the United States. The findings back up similar discoveries of platinum in an ice-core from Greenland by Harvard University researchers in 2013.
“Platinum is very rare in the Earth’s crust, but it is common in asteroids and comets,” says Christopher Moore, the study’s lead author and an archaeologist at Carolina. He calls the presence of platinum found in the soil layers at 11 archaeological sites in California, Arizona, New Mexico, Ohio, Virginia, North Carolina, and South Carolina an anomaly.
Asteroids are thought to contain not only platinum but other valuable metals including gold and iron ore. As such, several companies have embarked on projects to mine asteroids for these resources. Given the impracticalities and expense of transporting mining equipment and mined resources to and from deep space, some projects are not focused on bringing resources back to earth, but to use the water found in asteroids to make rocket fuel in space to enable further exploration. As we reported last year in Space: The Final Frontier… For Mining? NASA scientists suggest that advances in robotics and 3-D printing may lead to the development of self-sustaining machinery and tools that could make asteroid mining a reality.
Whether they come from space or the Earth, the platinum group metals (PGMs) are valued for their wide range of industrial, medical, and electronic applications. According to the 2017 U.S.G.S. Mineral Commodity Report on PGMs, the leading use for PGMs was in catalytic converters to decrease harmful emissions from automobiles. PGMs are also used in catalysts for bulk-chemical production and petroleum refining, in electronic applications, in multilayer ceramic capacitors, and in hybridized integrated circuits.
PGMs can be recovered from spent catalysts and other industrial products. Recycling PGMs from industry is much more successful than recovery from consumer electronics. Recycling efforts must be combined with careful elemental analysis of the recovered metal to determine its exact chemical composition and to ensure the metal is free from contaminants or hazardous materials. X-ray fluorescence (XRF) is a widely-used technology for this type of analysis. XRF analyzers determine the chemistry of a sample by measuring the fluorescent (or secondary) x-ray emitted from a sample when it is excited by a primary x-ray source. Because this fluorescence is unique to the elemental composition of the sample, XRF is an excellent technology for qualitative and quantitative analysis of the material composition.
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