A team of scientists have developed an updated model of Earth’s tectonic plates, offering insight into how the supercontinents were assembled 2.8 million years ago.
Supercontinents such as Pangaea, Gondwana, and Laurasia were vast land masses in Earth’s early history thought to have split and eventually form the continents as we know them at present. The latter, according to scientists, “drifted” about on tectonic plates - pieces of Earth's crust and uppermost mantle, collectively referred to as the lithosphere.
The fresh findings into our planet’s geological history, laid out by researchers from the University of Adelaide in the monthly peer-reviewed scientific journal Earth-Science Reviews, have been welcomed as invaluable in better understanding various natural hazards.
“Our new model for tectonic plates better explains the spatial distribution of 90 percent of earthquakes and 80 percent of volcanoes from the past two million years, whereas existing models only capture 65 percent of earthquakes,” said Derrick Hasterok, a lecturer with the Department of Earth Sciences at the University of Adelaide.
The team produced three new geological models: a plate model, a province model, and an orogeny (mountain formation) model. Such studies typically make use of geologic record, radioactive dating, seismic surveys, and other technologies to construct maps of how the world looked at various points in Earth’s history.
“We looked at the current knowledge of the configuration of plate boundary zones and the past construction of the continental crust,” said Hasterok, who led the team.
The new model, according to the scientists, includes fresh microplates such as the Macquarie microplate, located south of Tasmania, and the Capricorn microplate, that separates the Indian and Australian plates.
Tectonic plates are composed of Earth's crust and the uppermost portion of the mantle, with earthquakes typically occurring at the boundaries of the plates. This happens when one plate dips below another to thrust it upward.
“These new plate models show improved correlation to observed earthquake and volcano occurrences within deformation zones and microplates, compared with existing models, capturing 73 and 80 percent of these criteria, respectively,” the study said.
The Australian team had added more precise information concerning the boundaries of deformation zones. Previously, models had shown these as ‘discrete areas’ rather than ‘wide zones'.
“The biggest changes to the plate model have been in western North America, which often has the boundary with the Pacific Plate drawn as the San Andreas and Queen Charlotte faults. But the newly delineated boundary is much wider, approximately 1500km, than the previously drawn narrow zone,” Dr Hasterok explained. He added that the study revealed that another large change had taken place in central Asia.
Hailing the new model as now including "all of the deformation zones north of India”, scientists claimed it could be instrumental in improving prediction of earthquakes and volcanic eruptions, as well as better prospecting for minerals.