2024年5月21日 · Together, the two layers make up a craton, which is the foundation for a continent. One example of a shield is the Canadian Shield, which underlies modern-day Canada. Continents and cratons are not exactly the same thing.

The term shield cannot be used interchangeably with the term craton. However, shield can be used interchangeably with the term basement. The difference is that a craton describes a basement overlain by a sedimentary platform while shield only describes the basement.

A craton is an ancient part of the Earth's continental crust which has been more or less stable since Precambrian times. Cratons whose ancient rocks are widely exposed at the surface, often with relatively subdued relief, are known as shields .

The term craton is used to distinguish the stable portion of the continental crust from regions that are more geologically active and unstable. [4] Cratons are composed of two layers: a continental shield, in which the basement rock crops out at the surface, [5] and a platform which overlays the shield in some areas with sedimentary rock. [6]

2021年10月27日 · What is the difference between a craton, shield, and platform? A craton is the oldest, stable part of a continent. A shield is the exposed part of a craton with visible ancient rocks, whereas a platform is a part of the craton covered by recent sedimentary rocks.

2021年2月15日 · The craton region of North America includes the region between the Rocky Mountains (to the west) and the Appalachian Mountains (to the east) and include the Canadian Shield. A shield is a large area of exposed Precambrian-age crystalline igneous and high-grade metamorphic rocks that form tectonically stable areas.

The extensive central cratons of continents may consist of both shields and platforms. A shield is that part of a craton in which (usually) Precambrian basement rocks crop out extensively at the surface. By contrast, in a platform the basement is overlain by …

The ancient core of a continent, at and beneath the surface, is its craton. The cratonic rock that is seen at the surface is called the shield. Where the shield is covered by younger sediments is the platform.

We apply the term platform, a synonym of craton, to any large portion of the continental crust bounded by folded belts or sometimes by oceans, and characterized by the following specific features: (a) tectonic stability over a very long period (several hundreds of million years or more); (b) general tectonic homogeneity (despite a complex inner ...

A shield is defined as a craton in which basement rocks have been exposed by erosion at the surface; and such shields typically comprise Precambrian basement rocks. Cratons characteristically consist of ancient felsic igneous rocks in the crystalline basement at the center of continents, as distinguished from the linear belts of geosynclinal ...