Science Olympiad Dynamic Planet Practice Test

What is the term for a layer or series of layers of rock beneath the earth's surface?

1. Stratum

2. Lithosphere

3. Aquifer

4. Fjord

The correct answer is: Stratum

The term that describes a layer or series of layers of rock beneath the earth's surface is "stratum." In geology, a stratum (plural: strata) refers to a distinctive layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers. This concept is fundamental in understanding the Earth's geological history, as each stratum can provide insights into the conditions and environments that existed when the layer was formed. The other terms refer to different geological concepts. The lithosphere encompasses the rigid outer part of the Earth, which includes not only the uppermost solid layer of the mantle and the crust, but doesn't specifically refer to distinct layers. An aquifer is a geological formation that can store and transmit water, usually consisting of permeable rock layers, but it does not solely define the layered structure of rocks. A fjord is a deep, narrow, and elongated sea or lakedrain, typically formed by the submergence of a glaciated valley, and is not related to layers of rock beneath the surface.