14 DAY TRIAL // Scientists from CSIRO Minerals Down Under Flagship, led by researcher Dr. Stephen Barnes, have finally been able to put a timescale on the intricate convection processes that take place deep inside our planet, when they have determined how platinum is generated throughout the core. The convection processes inside the Earth are similar to those that move water in a pot of boiling water, except at a very massive scale. The experts have analyzed geological records and samples showing platinum concentrations, and have realized that the core slowly gained the precious metal over time.
Following the study, they believe that, when the core of our planet formed, some 4.5 billion years ago, it took all the heavy platinum down under with it, leaving none in the crust and the mantle. For the investigation, the platinum content of lava flows called komatiites was analyzed over extended periods of time. The results have revealed that the most ancient flows showed the least concentrations of platinum, whereas newer records show a significant increase. This has led Barnes to assume that the core slowly gained platinum over time, ScienceDaily informs.
“We found that the oldest komatiites have the lowest platinum content. The platinum content gradually increases from about 3.5 billion years to 2.9 billion years ago. This tells us that the deep source where the komatiite came from, down near the boundary between the Earth’s core and mantle, was gradually gaining platinum over time,” the scientist explains. “When the Earth’s core formed, it took all the available platinum with it, leaving the mantle and crust with none. Following that, a steady rain of meteorites created the so-called Late Veneer – a thin surface layer of meteorite debris rich in platinum.”
What followed was a very lengthy process, spanning more than 1.5 billion years. The large convection forces inside our planet, which would eventually form the tectonic plates and start moving them around, slowly mixed the outer surface layer into the planet's mantle, and afterwards the core, allowing it to gradually exhibit larger concentrations of platinum. Millions of years later, the precious metal began to resurface in komatiites in ever larger concentrations, a fact that shows in geological records.