Question

Which one of the following must have thickness less than 1 cm?

• A. Lamina
• B. Bed
• C. Straum
• D. Layer

Answer 1

The Correct Option is A

To solve the question of which geological feature must have a thickness of less than 1 cm, we need to understand the context of each term related to sedimentary structures.

• Lamina: In geology, a lamina is the thinnest layer within a sedimentary structure. By definition, a lamina typically measures less than 1 cm in thickness. This makes it the correct answer to this question.
• Bed: A bed is a larger, thicker sedimentary feature, usually greater than 1 cm in thickness. It consists of one or more layers or strata and can range from a few centimeters to several meters thick.
• Stratum (plural: Strata): A stratum is a single layer of sedimentary rock that can be distinguished from other layers. The thickness of strata can vary significantly and generally exceeds 1 cm.
• Layer: This is a general term used to describe any sheet or thickness of sedimentary deposits, which may refer to either a lamina or a bed. It does not specify the thickness directly.

The key detail here is the specific thickness criterion of being less than 1 cm, which clearly aligns with the definition of a lamina. As such, the correct answer is Lamina.