Rejuvenation in a mountainous terrain signifies a renewed phase of erosive activity by rivers, usually triggered by either tectonic uplift of the land or a significant fall in the base level (e.g., sea level drop). This invigorated erosive power leaves distinct morphotectonic imprints.

One prominent feature is incised meanders (or entrenched meanders). These are pre-existing, sinuous river courses that, instead of migrating laterally, cut vertically downwards into the bedrock due to the renewed uplift, forming spectacular, winding gorges or canyons. They retain their old meandering pattern but are now deeply entrenched.

Knickpoints, often manifesting as waterfalls or rapids, are abrupt breaks in a river's longitudinal profile. They represent the upstream migration of an erosional wave originating from the point of rejuvenation. As the river gains energy, it actively cuts down, and this point of enhanced erosion slowly moves upstream.

River terraces are another classic indicator. These are step-like remnants of former floodplains, abandoned as the river incises vertically due to rejuvenation, leaving the older floodplain stranded at a higher elevation. Multiple terraces suggest episodic uplift or base-level drops.

Finally, "valley-in-valley" topography often develops, where a narrower, deeper, younger valley is carved within an older, broader valley, reflecting two distinct cycles of erosion and renewed downcutting. These features collectively paint a clear picture of a landscape that has experienced a recent boost in its erosional energy.