New research from Curtin University has found a missing component in the composition of the continental crust. This new discovery opens up a new chapter in our planet’s geological history.
The issue that had been perplexing scientists up until now was the unusually high levels of nickel and chromium in the continental crust that current models could not explain.
Dr Andreas Beinlich, from the Curtin School of Earth and Planetary Sciences, said “Our current understanding is that the continental crust formed only by magmatic processes, meaning that igneous rocks formed by the crystallization of melt and eventually lumped together to form the crust.
“Our research was able to explore a new theory that the chemical composition of the crust can be more fully explained by the addition of weathered and eroded ultramafic rock, which is rich in magnesium, nickel and chromium but poor in silica.”
The team of international researchers collected rock samples from Norway, Canada and Western Australia that contributed to the study.
“We were able to determine that the amount of eroded rock required for compensating the nickel and chromium imbalance is small but still has a distinct effect on the chemical composition of the Earth’s crust,” Dr Beinlich said.
“Our research indicates that the transfer of nickel and chromium from the rock to the continental crust had to occur through weathering and erosion, essentially driven by chemical reactions between rocks and fluids including ocean water, rainwater and groundwater.
“Considering these fluid-rock reactions as a process that contributes to the formation of the continental crust offers a new explanation for understanding the formation of the Earth’s crust and its geological history.”
Source: Curtin University