Science Olympiad Dynamic Planet Practice Test

What do we call a stable block of crust that forms the nucleus of a continent?

1. Supercraton

2. Craton

3. Terrane

4. Plateau

The correct answer is: Craton

A stable block of crust that forms the nucleus of a continent is referred to as a craton. Cratons are typically ancient, tectonically stable portions of the continental crust that have remained largely unchanged for billions of years. They serve as the foundational core from which continental landmasses have grown over geological time. Cratons are characterized by their thick, stable lithosphere and are usually composed of highly metamorphosed rocks known as the shield, which is exposed at the surface in some regions. This stability and longevity allow them to play a crucial role in the geological history of continents, as they provide insights into the early formation of the Earth’s crust and the processes that contributed to the development of continental structures. In contrast, supercratons and terranes are not correct terms for the nucleus of continents. Supercratons typically refer to large, aggregated craton-like areas or those that are composed of multiple cratons, while terranes are smaller, distinct geological units that have been displaced from their original locations. Plateaus, while raised areas of land, do not necessarily imply the same geological stability or ancient origins as cratons. Hence, the term craton accurately describes the stable, foundational blocks of continental crust.