What are the common causes of unconformities?

There are multiple geological processes that can lead to the formation of unconformities, including:

- Non-deposition: This occurs when there is a break in sedimentation, and no new sediments are deposited. This can be caused by a variety of factors, such as a change in climate, sea level, or tectonic activity.

- Uplift and erosion: This occurs when an area of land is uplifted, exposing it to erosion. This can remove any existing sediments and create an unconformity.

- Folding and faulting: This occurs when rocks are folded or faulted, which can create an angular unconformity.

- Igneous activity: This occurs when magma intrudes into existing rocks or erupts onto the Earth's surface, covering any existing sediments and creating an unconformity.

- Metamorphism: This occurs when rocks are subjected to high temperatures and pressures, which can alter their texture and composition. This can create an unconformity between metamorphic rocks and the surrounding rocks.