Gondwana was a ‘supercontinent’ that existed between 500 and 180 million years ago. For the past four decades, geologists have debated how Gondwana eventually broke up, developing a multitude of scenarios which can be loosely grouped into two schools of thought – one theory claiming the continent separated into many small plates, and a second theory claiming it broke into just a few large pieces. Dr Eagles, working with Dr Matthais König from the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, has devised a new computer model showing that the supercontinent cracked into two pieces, too heavy to hold itself together.
Gondwana comprised of most of the landmasses in today’s Southern Hemisphere, including Antarctica, South America, Africa, Madagascar, Australia-New Guinea, and New Zealand, as well as Arabia and the Indian subcontinent of the Northern Hemisphere. Between around 250 and 180 million years ago, it formed part of the single supercontinent ‘Pangea’.
Evidence suggests that Gondwana began to break up at around 183 million years ago. Analysing magnetic and gravity anomaly data from some of Gondwana’s first cracking points – fracture zones in the Mozambique Basin and the Riiser-Larsen Sea off Antarctica – Dr Eagles and Dr König reconstructed the paths that each part of Gondwana took as it broke apart. The computer model reveals that the supercontinent divided into just two large, eastern and western plates. Approximately 30 million years later, these two plates started to split to form the familiar continents of today’s Southern Hemisphere.
‘You could say that the process is ongoing as Africa is currently splitting in two along the East African Rift,’ says Dr Eagles. ‘The previously held view of Gondwana initially breaking up into many different pieces was unnecessarily complicated. It gave fuel to the theory that a plume of hot mantle, about 2,000 to 3,000 kilometres wide, began the splitting process. A straight forward split takes the spotlight off plumes as active agents in the supercontinent’s breakup, because the small number of plates involved resembles the pattern of plate tectonics in the rest of Earth’s history during which plumes have played bit parts.’
According to Dr Eagles and Dr König’s study, because supercontinents like Gondwana are gravitationally unstable to begin with, and have very thick crusts in comparison to oceans, they eventually start to collapse under their own weight.
Says Dr Eagles, ‘These findings are a starting point from which more accurate and careful research can be made on the supercontinent. The new model challenges the positions of India and Sri Lanka in Gondwana which have been widely used for the past 40 years, assigning them very different positions in the supercontinent. These differences have major consequences for our understanding of Earth.’
Robert Massey | alfa
Time To Say Goodbye: The MOSAiC floe’s days are numbered
31.07.2020 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
Alaskan seismometers record the northern lights
30.07.2020 | Seismological Society of America
“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.
Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...
An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.
Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...
Although no life has been detected on the Martian surface, a new study from astrophysicist and research scientist at the Center for Space Science at NYU Abu...
New approach creates synthetic layered magnets with unprecedented level of control over their magnetic properties
The magnetic properties of a chromium halide can be tuned by manipulating the non-magnetic atoms in the material, a team, led by Boston College researchers,...
Scientists of Tomsk Polytechnic University jointly with a team of the V.E. Zuev Institute of Atmospheric Optics of the Siberian Branch of the Russian Academy of Sciences have discovered a method to increase the operation range of optical traps also known
Optical tweezers are a device which uses a laser beam to move micron-sized objects such as living cells, proteins, and molecules. In 2018, the American...
23.07.2020 | Event News
21.07.2020 | Event News
07.07.2020 | Event News
03.08.2020 | Information Technology
03.08.2020 | Information Technology
03.08.2020 | Life Sciences