Where are the majority of ocean trenches found quizlet?
Volcanic features on the ocean floor that are less than 1,000 meters (0.6 miles) tall are called: abyssal hills or seaknolls. Along the margins of the Pacific are found most of Earth’s: oceanic trenches.
How are ocean trenches formed quizlet?
How are ocean trenches created? Two oceanic plates collide at a convergent boundary. The older, denser oceanic crust subducts into the mantle. The ocean floor of the majority of the Atlantic Ocean forms at a divergent boundary along a mid-ocean ridge resulting in sea floor spreading.
What features are associated with a passive continental margin Choose all that apply?
Passive margins have narrower continental shelves. Convergent active margins have continental borderlands associated with basins and islands along the coast, whereas passive margins have a flat continental shelf.
What percent of Earth’s volcanic activity each year takes place on the seafloor?
Most seafloor spreading centers lie at depths exceeding 2,000 meters (1.2, miles) and, as a consequence, approximately three-quarters of all volcanic activity on Earth occurs as deep, underwater eruptions. The effects of these deep eruptions cannot be seen from the surface of the ocean.
What are the 3 parts of the continental margin?
The continental margins consist of three portions: (1) the continental shelf which has shallow water depths rarely deeper than 650 ft) and extends seaward from the shoreline to distances ranging from 12.3 miles to 249 miles, (2) the continental slope where the bottom drops off to depths of up to 3.1 miles, and (3) the …
What is the difference between an active and a passive continental margin?
An active continental margin is found on the leading edge of the continent where it is crashing into an oceanic plate. Passive continental margins are found along the remaining coastlines.
What is the best description of a passive margin?
Passive margins (also known as rifted margins) mark the sites where continents have rifted apart to become separated by an ocean. Thus, passive margins consist of a seawards tapering wedge of continental crust that is dissected by faults, overlain by sedimentary basins and juxtaposed with oceanic crust.
Where is a passive margin?
Passive margins are found at every ocean and continent boundary that is not marked by a strike-slip fault or a subduction zone. Passive margins define the region around the Atlantic Ocean, Arctic Ocean, and western Indian Ocean, and define the entire coasts of Africa, Greenland, India and Australia.
Why are most oceanic trenches found in the Pacific Ocean?
Why are most oceanic trenches found in the Pacific Ocean? The Pacific Ocean is shrinking and plates are descending below surrounding plates along its edges, hence the creation of trenches.
Why do passive margins have no trenches?
Explanation: Passive margins have no trenches because they do not have any tectonic plate activity.
What is a conjugate margin?
A conjugate margin pair comprises two passive margins now located on different tectonic plates, separated by oceanic crust (including a spreading axis), that were once adjoined in the rift system that preceded breakup.
Which ocean has the majority of oceanic trenches?
Trenches are long, narrow and very deep and, while most are in the Pacific Ocean, can be found around the world. The deepest trench in the world, the Mariana Trench located near the Mariana Islands, is 1,580 miles long and averages just 43 miles wide.
Why do only active margins have trenches answers com?
Trenches are caused by subduction. Only passive margins have subduction.
Which is not part of the continental margin?
Which of the following is NOT part of the continental margin? coral reefs surrounding a lagoon. You just studied 65 terms!
Do passive margins have volcanic activity?
Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere.
What are the two different kinds of continental margins How do they differ?
There are two types of continental margins: active and passive margins. Active margins are typically associated with lithospheric plate boundaries. These active margins can be convergent or transform margins, and are also places of high tectonic activity, including volcanoes and earthquakes.
What is the longest trench?
Peru-Chile Trench
Which best describes an ocean trench?
Which best describes an ocean trench? A deep, curved depression near the margin of a continent or chain of volcanic islands. Lava erupts from the mid-ocean ridge and is carried away as the floor of the ocean spreads apart.
How deep is the Kermadec Trench?
32,962 ft