Curtin University's new research on how terrestrial rocks formed billions of years ago has helped unravel the mystery of how the planet's unique plate tectonic behavior has changed over its life of over four billion years.
The research, published today in Nature, found that by comparing the temperature, pressure and age of ancient rocks, it was revealed that plate tectonics evolved gradually over the last 2.5 billion years while our planet cooled slowly.
Tim Johnson, chief Australian researcher at the School of Earth and Planetary Sciences at Curtin University, said the new research helped solve the ongoing debate on when and how the Earth plate tectonic system began.
"Metamorphic rocks are those that transform when they are buried and heated when the tectonic plates come together. Not only are they exceptionally beautiful, but they can also hold the key to unraveling the mystery of how Earth's unique plate tectonic behavior has changed over time, "said Dr. Johnson.
"Some geologists believe that the Earth has had plate tectonics during its existence of four and a half billion, while others believe that plate tectonics appeared abruptly about a billion years ago.
"Using a simple statistical analysis of the temperature, pressure and age of metamorphic rocks, we revealed that plate tectonics evolved gradually over the last 2.5 billion years as our planet slowly cooled."
Dr. Johnson said that a major focus of the research was on how Earth's tectonic processes could be changed through the Proterozoic Aeon, from 2.5 billion to 0.54 billion years ago, which represents almost half of the history of the Earth.
"It is discussed whether the tectonic plate processes we observe today can be used to interpret truly ancient rocks or if the Earth's tectonic processes were fundamentally different in the deep geological past," said Dr. Johnson.
"Understanding how the ancient Earth was different from the modern Earth is the key to accurately interpreting how terrestrial rocks were formed and why they are distributed across continents in the models we see, including where the mineral resources are located, how large they could be and where additional resources could be found. "
The research document was written by dr. Robert Holder and Professor Daniel Viete of Johns Hopkins University and Professor Michael Brown of the University of Maryland.
The "Metamorphism and evolution of plate tectonics" report is available online Here.
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