What is an angular unconformity?

An angular unconformity is a geological feature that occurs when there is a significant interruption in the deposition of sedimentary rock layers, resulting in a distinct age difference and orientation between the older and younger rocks. This process involves several steps: the older rock layers are first deposited horizontally, then they become tilted or folded due to tectonic forces. Following this deformation, the surface of these older rocks undergoes erosion, which wipes away some of the rock material. Finally, new sediment is deposited over the eroded surface of the older, tilted layers.

This process is key to understanding Earth's geological history, as angular unconformities provide evidence of significant temporal gaps and past geological activity, indicating that the area experienced tectonic upheaval and subsequent erosion before new layers were laid down. The presence of an angular unconformity reveals insights into the dynamic nature of the Earth’s crust and the processes that shape it over millions of years.