The statement that the oldest rock remains at the highest elevation is not always true. While older rocks are often found at higher elevations, there are several factors at play, and it's not a simple cause-and-effect relationship. Here's a breakdown of the complexities:

Factors influencing rock elevation:

* Tectonic uplift: The most significant factor is tectonic activity. Mountain ranges form when tectonic plates collide, pushing rock upward. This process can uplift even relatively young rocks to great heights.

* Erosion: Erosion, both by wind and water, wears away rock over time. This means that older rocks might have been eroded away to a greater degree than younger rocks, leaving the younger ones at higher elevations.

* Isostatic adjustment: The Earth's crust is not static; it adjusts to changes in mass. When massive amounts of material are removed (like through erosion), the crust rises in response. This can lead to older rocks, which were originally buried deeper, being exposed at higher elevations.

* Intrusive igneous rocks: Igneous rocks, formed from cooled magma, can intrude into existing rock formations. These intrusions can uplift and expose older rocks around them.

Why older rocks are *sometimes* found at higher elevations:

* Tectonic history: In some cases, older rocks might have been in place before major tectonic events that uplifted younger rock. These older rocks, once buried deeper, may now be exposed at higher elevations due to erosion and uplift.

* Erosion resistance: Some rock types are more resistant to erosion than others. Older rocks might be made of harder, more durable minerals, allowing them to withstand erosion better and remain at higher elevations.

Exceptions to the rule:

* Volcanoes: Volcanic mountains are often relatively young, with the youngest rock at the highest elevation.

* Sedimentary basins: Sedimentary rocks are often deposited in low-lying areas and are younger than the underlying basement rocks.

In conclusion:

While the statement about oldest rocks being at the highest elevation is a general observation, it is not always true. Many factors, including tectonic activity, erosion, isostatic adjustment, and the nature of the rock itself, contribute to the elevation of a rock formation. The relationship between rock age and elevation is complex and influenced by the specific geological history of the region.