New models showing how the continents were assembled provide new insights into Earth’s history and will help to better understand natural hazards such as earthquakes and volcanoes. “We examined the current knowledge about the configuration of the slab boundary zones and the previous construction of the continental crust,” said Dr. Derrick Hasterok, Lecturer, Department of Earth Sciences, University of Adelaide who led the team that produced the new models. “The continents were assembled a few pieces at a time, a bit like a puzzle, but each time the puzzle was finished, they were cut and reorganized to create a new image. Our study helps to illuminate the various elements so that geologists can combine the previous images. “We found that the plate boundary zones represented almost 16 percent of the Earth’s crust and an even higher percentage, 27 percent, of the continents.” “Our new model for tectonic plates better explains the spatial distribution of 90 percent of earthquakes and 80 percent of volcanoes over the last two million years, while existing models record only 65 percent of earthquakes.” – Dr. Derrick Hasterok, Lecturer, Department of Earth Sciences, University of Adelaide New models showing the architecture of the Earth. Credits: 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 orogenies – the process of mountain formation – that have left their mark on the current architecture of the crust. “Many of them, but not all, are related to the formation of supernatural beings,” said Dr. Hasterok. “Our work allows us to update the maps of the tectonic plates and the formation of continents found in the class textbooks. “These slab models, assembled from topographic models and global seismicity, have not been updated since 2003.” The new slab model includes many new microplates, including the Macquarie microplate in southern Tasmania and the Capricorn microplate that separates the Indian and Australian slabs. “To further enrich the model, we added more accurate information about the boundaries of the deformation zones: previous models showed them as discrete areas rather than wide bands,” said Dr. Hasterok. “The biggest changes to the plate model have taken place in western North America, which often borders the Pacific plate as far as the San Andreas and Queen Charlotte faults. But the recently demarcated border is much wider, about 1,500 km, than the previously designed narrow zone. “The other big change is in Central Asia. The new model now includes all the deformation zones in northern India, as the slab is bulldozed to Eurasia. A fairy tale told by the continents. Credits: Dr. Derrick Hasterok, University of Adelaide Published in Earth-Science Reviews, the team’s work provides a more accurate representation of the Earth’s architecture and has other important applications. “Our new model for tectonic plates better explains the spatial distribution of 90 percent of earthquakes and 80 percent of volcanoes in the last two million years, while existing models record only 65 percent of earthquakes,” said Dr. Hasterok. . “The slab model can be used to improve geo-hazard models. the orogeny model helps to understand geodynamic systems and better models the evolution of the Earth and the provincial model can be used to improve the search for minerals. Reference: “New Maps of Global Geological Provinces and Tectonic Plates” by Derrick Hasterok, Jacqueline A. Halpin, Alan S. Collins, Martin Hand, Corné Kreemer, Matthew G. Gard and Stijn Glorie, May 31, 2022, Earth-Science Reviews. DOI: 10.1016 / j.earscirev.2022.104069 The work involved researchers at the Universities of Adelaide, Tasmania, Nevada-Reno and the Australian Geosciences.
