Laboratory Experiments to Unravel Inner Secrets of Continents
Abstract
Continents are unique features of planet Earth, which set it apart from all other planets in the Solar System. Therefore, how continents formed and evolved through Earth's history is one of the deepest mysteries and fundamental questions in Earth Science. An intriguing aspect of continents is that at the core of continents are regions called cratons that have been stable and untouched by plate tectonic processes like mountain-building or earthquakes for billions of years. Continents are important not only because they provide stable land where humans can live, away from natural disasters but they can also moderate climate. Given the importance and uniqueness of continents in Earth processes and habitability of the planet, Earth scientists attempt to understand the physical structure and chemical composition of continents, especially the cratons. The surface of the cratons is made up of the crust that we live on, and is underlain by the mantle like the rest of the Earth, but here, processes that happen on the edge of the continental plates i-e where they collide or slide past or under each other are absent. One of the ways to explore the inaccessible deep regions underneath the continents, that are several tens of hundreds of kilometers beneath our feet is to use seismic waves that travel through the interior layers of the Earth like earthquake waves. The speed with which these seismic waves travel through the Earth's interior depends on properties of the material through which they travel, much like how sound travels slower underwater than in air. Such seismic waves reveal that cratons extend down to depths of 250 km. However, Earth scientists trying to understand processes that occur at depths inside the Earth must rely on laboratory experiments that allow us to mimic the high temperature and the high-pressure conditions inside the Earth. We can thus imitate processes that were taking place during the formation of these continents. By subjecting rocks that are synthesized in the lab to conditions inside the Earth [1], we can say that the physical features of cratons estimated via the study of seismic waves can be explained by the presence of some unique minerals. Laboratory experiments can thus reveal secrets of cratons that have enabled them to survive over time.
[1] Saha et al., 2018, G3- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.U54A..01G
- Keywords:
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- 6699 General or miscellaneous;
- PUBLIC ISSUES