Science Olympiad Dynamic Planet Practice Test

What is the term for a fragment of crustal material that has been accreted to a different tectonic plate?

1. Terrane

2. Crustal block

3. Subducted plate

4. Oceanic fragment

The correct answer is: Terrane

The correct term for a fragment of crustal material that has been accreted to a different tectonic plate is "terrane." Terranes are pieces of the Earth's crust that have distinct geological histories and characteristics and are often separated from the surrounding rock by fault lines. These geological units can vary greatly in size and composition, and their accretion occurs through processes such as tectonic plate movements, where one plate collides with and adds material from another. In geologic terms, understanding terranes is crucial because they can provide insights into the historical movements of the Earth's crust and the formation of mountain ranges and other geological features. The study of terranes helps geologists piece together the complex puzzle of Earth's geological past, revealing how continents have shifted over time. The other terms listed refer to different concepts. A "crustal block" is a more general term and is not necessarily associated with the specific process of accretion. A "subducted plate" refers to a tectonic plate that is being forced down into the mantle at a convergent boundary but does not imply the addition of crustal material to another plate. An "oceanic fragment" typically describes a piece of the oceanic crust but doesn't specifically address the process of