What is a sea stack?

A sea stack is defined as a coastal feature that appears as a vertical column of rock. This geological formation is created through processes like erosion, where waves and weathering wear away the base of a cliff, eventually isolating a column of rock from the mainland as the surrounding rock is eroded away. Over time, this column stands alone as a stack, often visible from the shore.

The formation process of a sea stack highlights key aspects of coastal erosion and the impact of natural forces on coastal landscapes. Sea stacks often indicate the strength of wave action in the area and can serve as important habitats for various marine life.

In regards to the other options, while a narrow flat area of rock at the base of a sea cliff is known as a wave-cut platform, and a hole through a headland would be classified as an arch, these terms do not describe the distinct vertical characteristics associated with a sea stack. A short sea stack may refer to a smaller version of a sea stack but does not accurately describe the defining nature of what a sea stack is. Hence, the best definition aligns with that of a vertical column of rock.