How does land uplift affect stream terrace formation?

Land uplift plays a significant role in stream terrace formation by elevating the land beneath a stream, which ultimately contributes to the development of terraces. As the land rises, the river's base level does not change immediately, but the stream will respond to this uplift by incising into its own bed over time. This process creates a set of steps or flat surfaces, known as terraces, which represent former river levels before the uplift occurred. Each terrace can correspond to a period of stability followed by a downcutting phase as the river adjusts to the elevated landscape, carving new channels into the former floodplain.

The other alternatives do not accurately describe the interaction between land uplift and stream terrace formation. Some suggest effects like subsidence of the riverbed or raising the base level, which do not align with the mechanics of how uplift directly influences river dynamics and terrace creation. Instead, the consistent rise in the land enhances the relative elevation of existing structures, leading to the formation of distinct terrace levels as the river adjusts.