Which term refers to the accumulation of sediment along the landward margin of the ocean?

The term that refers to the accumulation of sediment along the landward margin of the ocean is a beach. A beach is typically formed through the processes of erosion and deposition, where waves and currents transport sediment such as sand, gravel, and pebbles from the seabed and deposit them along the shoreline. This accumulation creates the distinct landform we recognize as a beach, which acts as a transition zone between terrestrial and marine environments.

The other terms listed relate to different geological or oceanographic phenomena. Tides are the periodic rise and fall of sea levels caused by gravitational forces from the moon and sun, not an accumulation of sediment. A spring is a natural source of groundwater that flows to the earth's surface, unrelated to ocean margins. A geyser is a hot spring that periodically erupts with steam and hot water, which is also not associated with sediment accumulation along shorelines. Thus, the defining characteristic of a beach as a sedimentary environment makes it the correct answer.