What are striations?

Striations refer to grooves or scratches found on rocks, which result from the movement of glaciers across the Earth's surface. As a glacier moves, it picks up sediments and debris, and when it slides over the bedrock, it can leave behind these distinct marks. These grooves indicate the direction of glacial flow and are significant in studying past glaciation events.

The other options involve different geological processes. The lines of sediment deposited by rivers relate to fluvial geology, while layers of soil formed by erosion pertain to soil formation processes and the effects of weathering. Chemical deposits from ancient waters refer to mineral accumulation due to evaporation or chemical precipitation, which is common in sedimentary environments but does not involve glacial activity. Understanding striations is crucial in the study of glaciology and the effects of ice ages on landscapes.