In 2016, the geochemists
Jonas Tusch and
Carsten Münker hammered a thousand pounds of rock from the Australian Outback and airfreighted it home to Cologne, Germany.
Five years of sawing, crushing, dissolving and analyzing later, they have coaxed from those rocks a secret hidden for eons: the era when plate tectonics began.
Earth’s fractured carapace of rigid, interlocking plates is unique in the solar system. Scientists increasingly connect it to our planet’s other special features, such as its stable atmosphere, protective magnetic field and menagerie of complex life. But geologists have long debated exactly when Earth’s crust broke into plates, with competing hypotheses spanning from the first billion years of the planet’s 4.5-billion-year history to sometime in the last billion. Those estimates have wildly different implications for how plate tectonics affects everything else on Earth.
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