New model of the tectonic plate with boundary zones in darker shades. Credit: Dr. Derrick Hasterok, University of Adelaide
The new models, which show how the continents are assembled, provide a fresh look at the Earth’s history and will help to better understand natural hazards such as earthquakes and volcanoes.
“We looked at current knowledge of the configuration of the boundary areas of the slabs and the past construction of the continental crust,” said Dr. Derrick Gasterok, a professor in the Department of Earth Sciences at the University of Adelaide who led the team that produced the new models.
“The continents were put together in several pieces at once, a bit like a puzzle, but each time the puzzle was completed, it was cut and reorganized to create a new picture. Our research helps to illuminate the various components so that geologists can collect previous images.
“We found that the boundary areas of the plates represent nearly 16 percent of the earth’s crust and an even higher share, 27 percent, of the continents.
“Our new tectonic plate model better explains the spatial distribution of 90 percent of earthquakes and 80 percent of volcanoes over the past two million years, while existing models capture only 65 percent of earthquakes.
– Dr. Derrick Hasterok, Lecturer, Department of Earth Sciences, University of Adelaide
New models showing the architecture of the Earth. Credit: Dr. Derrick Hasterok, University of Adelaide
The team produced three new geological models: a plate model, a province model and an orogeny model.
“There are 26 orogenesis – the process of mountain formation – that have left their mark on today’s crustal architecture. Many, but not all, are related to the formation of supercontinents, “said Dr. Gasterok.
“Our work allows us to update maps of tectonic plates and the formation of continents that are found in textbooks in the classroom. These slab models, which are assembled from topographic models and global seismicity, have not been updated since 2003.
The new model of the plate includes several new microplates, including the Macquarie microplate, which is located south of Tasmania, and the Capricorn microplate, which separates the Indian and Australian plates.
“To further enrich the model, we added more accurate information about the boundaries of the deformation zones: previous models showed them as discrete areas, not as wide areas,” said Dr. Gasterok.
“The biggest changes in the model of the slab are in the western part of North America, which often has the border with the Pacific slab, drawn as the San Andreas and Queen Charlotte faults. But the newly delineated border is much wider, approximately 1,500 km, than the pre-delineated narrow area.
“The other big change is in Central Asia. The new model now includes all deformation zones north of India as the slab makes its way with bulldogs in Eurasia.
A tale told by the continents. Credit: Dr. Derrick Hasterok, University of Adelaide
Published in the journal Earth-Science Reviews, the team’s work provides a more accurate representation of Earth’s architecture and has other important applications.
“Our new tectonic plate model better explains the spatial distribution of 90 percent of earthquakes and 80 percent of volcanoes over the past two million years, while existing models capture only 65 percent of earthquakes,” said Dr. Gasterok.
“The sign model can be used to improve geohazard risk models; The orogeny model helps to understand geodynamic systems and a better model of Earth’s evolution, and the provincial model can be used to improve mineral demand.
Reference: “New Maps of Global Geological Provinces and Tectonic Plates” by Derrick Gasterok, Jacqueline A. Halpin, Alan C. Collins, Martin Hand, Corne Krimer, Matthew G. Gard and Steen Glory, May 31, 2022, reviews for the Earth. DOI: 10.1016 / j.earscirev.2022.104069
The work involved researchers from the universities of Adelaide, Tasmania, Nevada-Reno and Geoscience Australia.
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