Subduction is the process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle.
What is the process that continually adds new crust to the ocean floor along both sides of the mid-ocean ridge?
A ridge forms along a crack in the oceanic crust. At a mid-ocean ridge, molten material rises from the mantle and erupts. The molten material then spreads out, pushing older rock to both sides of the ridge. ... This process, called sea-floor spreading , continually adds new material to the ocean floor.
Which term refers to the process in which the ocean floor goes beneath a deep ocean trench and recycled back into the asthenosphere?
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth’s mantle at convergent boundaries. ... The process of subduction has created most of the Earth’s continental crust.
What process is taking place at the trenches?
Trenches are formed by subduction , a geophysical process in which two or more of Earth’s tectonic plates converge and the older, denser plate is pushed beneath the lighter plate and deep into the mantle, causing the seafloor and outermost crust (the lithosphere) to bend and form a steep, V-shaped depression.
What is the process of seafloor spreading?
Seafloor spreading is a geologic process in which tectonic plates—large slabs of Earth’s lithosphere—split apart from each other . ... The less-dense material rises, often forming a mountain or elevated area of the seafloor. Eventually, the crust cracks.
Are deep ocean trenches geologically stable?
They are not geologically very stable because volcanic activity and earthquakes are always associated with deep-ocean trenches.
What is the Earth deepest point called?
The Mariana Trench , in the Pacific Ocean, is the deepest location on Earth. According to the Exclusive Economic Zone (EEZ), the United States has jurisdiction over the trench and its resources.
What happens when two plates carrying continental crust collide?
Plates Collide When two plates carrying continents collide, the continental crust buckles and rocks pile up, creating towering mountain ranges . The Himalayas were born when the Indian subcontinent smashed into Asia 45 million years ago.
What happens to old oceanic crust at the trenches as new molten material rises from the mid-ocean ridge?
What happens to old oceanic crust as new molten material rises from the mantle? The molten material spreads out, pushing older rock to both sides of the ridge . It sinks down due to density. ... The Earth’s ocean floors move like conveyor belts, carrying the continents along with them, as they move.
What is it called when the ocean floor sinks back into the mantle?
Subduction is the process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle.
Is the Mariana Trench still forming?
The Mariana Trench was formed through a process called subduction . ... Today, the majority of the Mariana Trench is a U.S. protected zone as part of the Marianas Trench Marine National Monument, established in 2009.
Where are deep sea trenches found?
These chasms are the deepest parts of the ocean—and some of the deepest natural spots on Earth. Ocean trenches are found in every ocean basin on the planet , although the deepest ocean trenches ring the Pacific as part of the so-called “Ring of Fire” that also includes active volcanoes and earthquake zones.
What is the first step of seafloor spreading?
1. A long crack in the oceanic crust forms at a mid ocean ridge . 2. Molten material rises and erupts along the ridge.
What are the three types of seafloor spreading?
There are three types of plate-plate interactions based upon relative motion: convergent, where plates collide, divergent , where plates separate, and transform motion, where plates simply slide past each other.
What are two pieces of evidence for seafloor spreading?
Several types of evidence from the oceans supported Hess’s theory of sea-floor spreading- evidence from molten material, magnetic stripes, and drilling samples . This evidence also led sci- entists to look again at Wegener’s theory of continental drift.
What is the importance of seafloor spreading?
Significance. Seafloor spreading helps explain continental drift in the theory of plate tectonics . When oceanic plates diverge, tensional stress causes fractures to occur in the lithosphere.
