Which landform forms at the mouth of a river when sediments are deposited to create a triangular area?

Prepare for the IB Marine Science SL Exam. Use flashcards and multiple-choice questions with detailed explanations. Master marine ecosystems, ocean currents, and biological resources for success!

Multiple Choice

Which landform forms at the mouth of a river when sediments are deposited to create a triangular area?

Explanation:
When a river reaches the sea, its speed drops and its sediment settles out. As this sediment builds up where the river spreads into the ocean, it fans out and advances seawards, creating a wedge‑shaped landform that extends into the mouth. This is a delta. The triangular shape comes from the distributaries spreading the sediment as the flow splits and deposits material, rather than just along the shoreline. Other options describe different coastal features (a coast as the general shoreline, a beach as a sandy shore formed by wave action, the berm crest as part of a beach profile), but they don’t describe a landform formed specifically by river sediments at the mouth.

When a river reaches the sea, its speed drops and its sediment settles out. As this sediment builds up where the river spreads into the ocean, it fans out and advances seawards, creating a wedge‑shaped landform that extends into the mouth. This is a delta. The triangular shape comes from the distributaries spreading the sediment as the flow splits and deposits material, rather than just along the shoreline. Other options describe different coastal features (a coast as the general shoreline, a beach as a sandy shore formed by wave action, the berm crest as part of a beach profile), but they don’t describe a landform formed specifically by river sediments at the mouth.

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