Sediment sources are best described as?

• A. Earth materials carried by rivers, glaciers, winds
• B. Organic material produced by plankton
• C. Atmospheric gases
• D. Minerals formed in rocks

Answer: (A)

The main idea here is the origin of the material that becomes sediment. Sediment sources are the materials that supply sediment, coming from the weathering and erosion of existing rocks and minerals. Those materials are then transported by natural processes such as rivers, glaciers, and wind to new locations where they are deposited. That’s why earth materials carried by rivers, glaciers, and winds best describe sediment sources.

Biogenic material, like organic matter produced by plankton, is a type of sediment content rather than the origin of the sediment itself. Atmospheric gases aren’t sediment, and minerals formed in rocks refer to formation inside rocks rather than the transportable material that becomes sediment.