What physical phenomenon is depicted by a geologic cross section?

A geologic cross section provides a vertical slice through the Earth's crust, allowing for a detailed view of the internal structure of subsurface geology. It illustrates how various rock layers are arranged, their compositions, and their relationships to one another. This representation is crucial for understanding geological features, such as faults, folds, and stratigraphy, which are not visible from the surface but are essential for interpreting the geological history and processes that shape an area.

In contrast, a topographical map focuses on surface features, showing elevations and landforms but does not provide insights into what lies beneath the surface. Temperature fluctuations within rock formations, while relevant in some geological contexts, are not directly represented in a geologic cross section. Additionally, gravitational forces may influence geological processes, but they are not depicted in the structural representation provided by a cross section. Thus, the correct choice emphasizes the cross section's role in revealing the complex internal arrangement of geological formations.