What are circular depressions found in limestone regions typically referred to?

The term used to describe circular depressions found in limestone regions is "dolines." Dolines are typically formed through the processes of chemical weathering and erosion, specifically in karst landscapes where the dissolution of soluble rocks like limestone occurs.

In these areas, rainwater, which is slightly acidic due to dissolved carbon dioxide, seeps into the ground and gradually dissolves the limestone, creating voids beneath the surface. Over time, the ground may collapse into these voids, forming a circular depression known as a doline.

Dolines can vary in size and depth and are an essential feature of karst topography, indicating the presence of a subsurface drainage system. Understanding dolines is important in geology and hydrology, as they can affect groundwater flow and influence the ecosystem.