Outer Continental Shelf

The outer continental shelf is the distal, seaward part of the continental shelf, extending from roughly mid-shelf out to the shelf break near 120 to 140 meters depth. It is dominated by relict sediment deposited during Quaternary lowstands and reworked little by present currents, because the modern wave base does not reach it. Many outer shelves carry drowned shorelines, sand ridges, and reef terraces from past sea-level stands. The zone is the legal and resource frontier for offshore oil, gas, and minerals, and it grades at the shelf break into the continental slope. It contrasts with the wave-swept inner shelf.