What can multiple wave-cut platforms reveal about past sea levels?

Multiple wave-cut platforms along a coastline serve as significant geological indicators of past sea levels. Because a single wave-cut platform forms over a period of time when the sea level remains stable, the presence of multiple, vertically stacked platforms suggests that the sea level fluctuated or that the land underwent tectonic uplift over time.12

When these platforms are raised above the current high-tide level, they are referred to as marine terraces. By studying these terraces, geologists can calculate the extent of coastal uplift or the historical lowering of sea levels. In tectonically active regions, such as New Guinea, these suites of terraces provide a record of past high sea-level intervals, helping researchers correlate coastal changes with broader geological events like glaciations. Conversely, if sea levels rise, these platforms may become submerged, effectively ending their formation process.23