What happens at an oceanic ridge?
Mid-ocean ridges occur along divergent plate boundaries, where new ocean floor is created as the Earth's tectonic plates spread apart. As the plates separate, molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt.
Why are mid ocean ridges elevated compared to the surrounding ocean floor quizlet?
The Mid-Oceanic Ridge is elevated above surrounding seafloor because it is made of hotter and less dense lithosphere than oceanic crust farther away from the divergent boundary.
What feature of the ocean floor develops where the oceanic lithosphere bends downward and sinks into the mantle quizlet?
Which develops where oceanic lithosphere bends downward and sinks into the mantle? Deep ocean trenches. The seafloor spreading rates along the Mid-Atlantic and Mid-Indian ocean ridges are: 1 to 5 centimeters per year.
Why are the mid ocean ridges elevated?
Since hot rocks are in a more expanded state and then contract as they cool (as they spread away from the ridge), the midocean ridges stand up high above the surrounding seafloor. The seafloor depth increases with distance away from the midocean ridges.
How far does North America move every million years?
Plate motion For the most part, the North American Plate moves in roughly a southwest direction away from the Mid-Atlantic Ridge at a rate of about 2.3 centimeters (~1 inch) per year. At the same time, the Pacific Plate is moving to the northwest at a speed of between 7 and 11 centimeters (~3-4 inches) a year.
Where do some rift valleys form along the oceanic ridge system?
Over millions of years, the Mid-Atlantic Ridge has formed rift valleys as wide as 15 kilometers (9 miles). In the Pacific Ocean, the East Pacific Rise has created rift valleys where the Pacific plate is separating from the North American plate, Cocos plate, Nazca plate, and Antarctic plate.
Why are mid-ocean ridges important to the theory of plate tectonics quizlet?
Rising mantle material at mid-ocean ridges creates the potential for plates to move away from the ridge with a force(ridge push). When tectonics plate collide, the denser plate will sink into the mantle along a subduction zone.
What occurs at mid-ocean ridges quizlet?
Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics.
Where does seafloor spreading occur quizlet?
Where does seafloor spreading occur? This process occurs along divergent plate boundaries at areas called mid-ocean ridges.
What happens to the seafloor at trenches quizlet?
What happens to oceanic crust at a deep-ocean trench? At a deep-ocean trench, the oceanic crust bends downward. In a process taking tens of millions of years, part of the ocean floor sinks back into the mantle at deep-ocean trenches.
What is the difference between Rift Valley and mid-ocean ridge?
Continental rift zones occur in weak spots in the continental lithospheric plate. A mid-ocean ridge usually originates in a continental plate as a rift zone that expands to the point of splitting the plate apart, with seawater filling in the gap.
What stage is marked by the creation of a well formed ocean basin with a mid-ocean ridge in the middle?
Stage C, is when a large ocean has formed between two continental margins and spreading still occurs. A well developed mid ocean ridge has formed along the divergent boundary. The Atlantic Ocean is an example of stage C.
Is it possible for the continents to be united again?
Just as our continents were once all connected in the supercontinent known as Pangea (which separated roughly 200 million years ago), scientists predict that in approximately 200-250 million years from now, the continents will once again come together.
When did Africa collide with North America?
about 230 million years ago After years of drifting toward each other, the continental plates of North America and Africa collided about 230 million years ago. Like a slow-motion car crash, the land edges crumpled and the two continents welded together, pushing up one large mountain range, the Appalachians.
What is the difference between rift valley and mid-ocean ridge?
Continental rift zones occur in weak spots in the continental lithospheric plate. A mid-ocean ridge usually originates in a continental plate as a rift zone that expands to the point of splitting the plate apart, with seawater filling in the gap.
Where is mid-ocean ridge?
The Mid-Atlantic Ridge extends from south of Iceland to the extreme South Atlantic Ocean near 60° S latitude. It bisects the Atlantic Ocean basin, which led to the earlier designation of mid-ocean ridge for features of this type.
What happens at mid-ocean ridges quizlet?
Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics.
How an oceanic transform boundary is related to seafloor spreading at a mid-ocean ridge?
1 Introduction. Most of Earth's crust, both present and in the past, was formed along the global mid-ocean ridge (MOR) system where two oceanic plates are pulled apart. A fundamental feature of this seafloor spreading is the formation of transform faults of varying length that offset the ridge segments at 90°.
What is the name of the process that occurs at the mid-ocean ridge?
This rock (basalt) becomes a new part of Earth's crust. Mid-Ocean Ridges Seafloor spreading occurs along mid-ocean ridges—large mountain ranges rising from the ocean floor.
Where are ocean trenches formed?
An ocean trench is a deep indent in the surface floor of the ocean and is the deepest part of the ocean. Trenches are located in subduction zones at or near a convergent boundary, continental crust, and/ or volcanic islands.
Where does seafloor spreading mostly occur?
Mid-Ocean Ridges Seafloor spreading occurs along mid-ocean ridges—large mountain ranges rising from the ocean floor. The Mid-Atlantic Ridge, for instance, separates the North American plate from the Eurasian plate, and the South American plate from the African plate.
Where would seafloor spreading most likely occur?
Seafloor spreading is a phenomenon that occurs at mid-oceanic ridges, such as the Mid-Atlantic Ridge.
What has been found at the bottom of the ocean?
A recent study revealed that a plastic bag, like the kind given away at grocery stores, is now the deepest known piece of plastic trash, found at a depth of 10,975 meters (36,000 feet) inside the Mariana Trench.
Which statement describes one event that happened at deep-ocean trenches?
Which statement describes one event that happens at deep-ocean trenches? Denser plates slide under lighter plates.
Which feature is formed near the divergent boundaries between two plates of oceanic crust?
oceanic spreading ridges Along these boundaries, magma rises from deep within the Earth and erupts to form new crust on the lithosphere. Most divergent plate boundaries are underwater and form submarine mountain ranges called oceanic spreading ridges.
What is a rift valley in the ocean?
Rift valleys – Rift valleys are confined to the central axis of mid-ocean spreading ridges; they are elongate, local depressions flanked generally on both sides by spreading ridges (Macdonald, 2001).
What is embryonic ocean basin?
A stable continent (Craton) with a hot spot underneath which can lead to the beginning of a new ocean, lookup Wilson cycle, stage A. Categories: All Articles, Land & Geology.
What will the Earth look like in 250 million years?
1:388:43What will the world look like in 250 million years? – YouTubeYouTube
Is Australia moving north?
The eastern part (Australian Plate) is moving northward at the rate of 5.6 cm (2.2 in) per year while the western part (Indian Plate) is moving only at the rate of 3.7 cm (1.5 in) per year due to the impediment of the Himalayas.
What will the Earth look like in 50 million years?
This is the way the World may look like 50 million years from now! If we continue present-day plate motions the Atlantic will widen, Africa will collide with Europe closingthe Mediterranean, Australia will collide with S.E. Asia, and California will slide northward up the coast to Alaska.