Beyond these three uses, there is much disagreement over when to capitalize. Every major publication and publisher has its own standards, and many writers have their own preferences (which are generally overridden by in-house rules during publication).
Deep-sea trench. Deep-sea trench, also called oceanic trench , any long, narrow, steep-sided depression in the ocean bottom in which occur the maximum oceanic depths, approximately 7,300 to more than 11,000 metres (24,000 to 36,000 feet). They typically form in locations where one tectonic plate subducts under another.
Of the Earthâs 20 major trenches, 17 are found in the Pacific basin, a vast area rimmed by trenches of both marginal and island arc varieties. Marginal trenches bound the west coast of Central and South America from the Gulf of California to southern Chile.