Here's why:

* Terrigenous means "derived from land". This sediment is transported from land to the ocean by rivers, wind, glaciers, and other processes.

* Continental margins are the areas of the ocean floor that are closest to land, making them prime locations for terrigenous sediments to accumulate.

Examples of terrigenous sediments include:

* Sand: Made up of weathered rock fragments, often carried by rivers.

* Clay: Fine-grained sediment, often transported by wind or rivers.

* Silt: Sediment with particles between the size of sand and clay.

While other types of sediments may be present in smaller amounts, terrigenous sediment is the dominant type near continents.