Answer:
Estuaries and sea arches are coastal landforms that occur when the sea level rises relative to the land.
Step-by-step explanation:
When the sea level rises relative to the land, the following coastal landforms occur:
- Estuaries: Estuaries are coastal areas where a river meets the sea. As the sea level rises, estuaries form when the rising water inundates the lower-lying river valleys and creates a semi-enclosed coastal body of water. Estuaries are characterized by brackish water, a mix of freshwater and seawater, and are often home to unique ecosystems and diverse wildlife.
- Sea arches: Sea arches are natural arches or bridges that form along coastal cliffs or headlands. They occur when the sea erodes the softer rock layers beneath harder layers, creating a hole or tunnel that extends through the headland. As the sea level rises, the base of the sea arch can become submerged, transforming it into a sea stack or isolated pillar of rock.
In contrast, terraces and fjords are not directly formed by the rising sea level relative to the land:
- Terraces: Terraces are flat, elevated landforms found along coastlines. They are typically formed through a combination of tectonic activity, erosion, and sea level changes over long periods. Terraces can occur at different elevations, reflecting past sea levels, but they are not directly related to rising sea levels in the present.
- Fjords: Fjords are narrow, deep inlets that form when glaciers carve U-shaped valleys. They are typically found in high-latitude regions and are not directly influenced by changes in sea level. Fjords are created by glacial erosion, with the weight of the ice pushing the land downward, creating a deep channel that becomes flooded by the sea when the glacier retreats.
In summary, estuaries and sea arches are coastal landforms that occur when the sea level rises relative to the land. Terraces and fjords, on the other hand, are not directly formed by rising sea levels but are shaped by other geological processes.