[48] However, Wegener did not pursue this observation in his later works and his theory was dismissed by geologists because there was no mechanism to explain how continents could plow through ocean crust, and the theory became largely forgotten. The first discovered mid-ocean ridge was the Mid-Atlantic Ridge, which is a spreading center that bisects the North and South Atlantic basins; hence the origin of the name 'mid-ocean ridge'. The Midlina Bridge connects two plates. As crystallized basalt extruded at a ridge axis cools below Curie points of appropriate iron-titanium oxides, magnetic field directions parallel to the Earth's magnetic field are recorded in those oxides. Active & Passive Continental Margins | Overview, Types & Examples, Changes in Sea Level: Causes & the Effect on the Environment, Evidence for the Mechanism of Continental Drift. This dataset shows the age of the ocean floor along with the labeled tectonic plates and boundaries. Running down the middle of the mid-ocean ridge is a rift valley 25-50 km wide and 1 km deep. Mid-Atlantic Ocean Ridge Plate Boundaries Plate Movement Seafloor Seafloor Age Seafloor Spreading Tectonics Transform Boundaries Download Dataset Files (FTP) Video (Download) Image (Download) Add to Playlist View My Playlist Description Permalink to Description There are three main mid-ocean ridges found on Earth. C5 Energy and Matter. ESS1.C The History of Planet Earth. Students learn changes in one part of a system might cause large changes in another part, systems in dynamic equilibrium are stable due to a balance of feedback mechanisms, and stability might be disturbed by either sudden events or gradual changes that accumulate over time. The crust, formed by tectonic plates, lies atop the mantel, a layer of thick, viscous material known as magma. This is a slow-spreading center that spreads apart at a rate of 0.8 to 2 inches per year. PS2.B Types of Interactions. Later, more lava erupts and pushes the original seafloor outward. To back up, a mid-ocean ridge represents what originally started off as a continental rift, something like the East African Rift today. When the fissure opens, pressure is reduced on the super-heated mantle material below. As a result, the oceanic crust is broadened, but existing landmasses are also obliterated. WebThe Mid-Atlantic Ridge is an example of divergent plate boundaries. This feature is where seafloor spreading takes place along a divergent plate boundary. Learn the mid-ocean ridge definition and see a mid-ocean ridge example. 
They also understand that phenomena may have more than one cause, and some cause and effect relationships in systems can only be described using probability. Divergent plate boundaries are locations where plates are moving away from one another. Most mid-ocean ridges are located deep below the sea. A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. [6] The overall shape of ridges results from Pratt isostacy: close to the ridge axis, there is a hot, low-density mantle supporting the oceanic crust. Seafloor spreading Seafloor global topography: cooling models, Plate tectonics Development of the theory, "What is the longest mountain range on earth? WebIn Earth's current lithospheric plate configuration, the mid-ocean ridge system extends connected for over 60,000 km making them also the longest mountain chain and plate The mid ocean ridge is the longest mountain range on Earth. Much like a hot spring on the ocean floor, hydrothermal vents occur where heated fluid is propelled through the Earth's crust. Some other interesting mid-ocean ridge facts include: Mid-ocean ridges represent a chain of underwater mountains formed by seafloor spreading at divergent plate boundaries. This magma oozes out onto the seafloor to form pillow basalts, breccias (fragmented basaltic rock), and flows, interbedded in some cases with limestone or chert. They understand events that occur together with regularity might or might not signify a cause and effect relationship. Volcanic activity sometimes occurs within the rift. G is measured in marine surveys at a lower rate than in land surveys, which are commonly referred to as free-air anomalies. This slow spreading ridge deposits new ocean crust at a rate of 2 to 5 centimeters, or 0.8 to 2 inches, per year. Concept note-5: -Most divergent boundaries are located along mid-ocean oceanic ridges (although some are on land). This new crust is formed due to igneous intrusions and extrusions as magma either cools beneath the Earth's surface or erupts as lava above the Earth's surface. 
Forces that act at a distance involve fields that can be mapped by their relative strength and effect on an object. In Iceland, the Mid-Atlantic Ridge is above sea level. Students can investigate or analyze a system by defining its boundaries and initial conditions, as well as its inputs and outputs. Because a majority of this mountain range is located below the ocean, few people have ever seen it up close, and many people don't know about this massive feature on Earth. Most divergent boundaries are located along mid-ocean oceanic ridges (although some are on land). Students learn some systems appear stable, but over long periods of time they will eventually change. Scientists named it the 'Mid-Atlantic Ridge'. This action creates mountains. AP Environmental Science: Tutoring Solution, AP Environmental Science - Oceans: Tutoring Solution, Psychological Research & Experimental Design, All Teacher Certification Test Prep Courses, Introduction to AP Environmental Science: Tutoring Solution, AP Environmental Science - Geologic Time: Tutoring Solution, AP Environmental Science - Plate Tectonics: Tutoring Solution, AP Environmental Science - Earthquakes: Tutoring Solution, AP Environmental Science - Volcanoes: Tutoring Solution, AP Environmental Science - The Atmosphere and the Environment: Tutoring Solution, AP Environmental Science - Weather and Storms: Tutoring Solution, AP Environmental Science - Water Balance: Tutoring Solution, AP Environmental Science - Running Water: Tutoring Solution, AP Environmental Science - Ground Water: Tutoring Solution, AP Environmental Science - Glaciers: Tutoring Solution, Ocean Basins: Definition, Formation, Features & Types, Ocean Circulation: Patterns & Effect on Climate, Waves: Types, Features & Effect on Erosion, Contributing Factors of Longshore Transport: Beach Drift & Longshore Current, Mid-Ocean Ridge: Definition, Facts, Formation & Example, What is Plankton? The oldest oceanic crust is around 280 Ma in the eastern Mediterranean, and the oldest parts of the open ocean are around 180 Ma on either side of the north Atlantic. [17][18] Hydrothermal vents fueled by magmatic and volcanic heat are a common feature at oceanic spreading centers. The East Africa Rift is in a very early stage of development. Iceland is a location where we can see a mid-ocean ridge above sea level. WebThe first sort of plate boundary is called a divergent boundary, or spreading center. 1 April 2010. Two locations are marked within the rift valley of East Africa, and another location is marked within the Red Sea. A plate boundary is a location where the plates that are moving away from one another are so Divergent. An oceanographer will give you a far better response than I can, young lady. [25] In slab pull the weight of a tectonic plate being subducted (pulled) below an overlying plate at a subduction zone drags the rest of the plate along behind it. This type of boundary is also known as a spreading boundary. Maps can be used to locate features and determine patterns in those events. low topographic ridge in ocean basin oceanic trench no earthquakes shallow earthquakes only shallow and deep earthquakes underwater The Ridge is a high area compared to the surrounding seafloor because of the lift from the convection current below. They also learn within a natural or designed system, the transfer of energy drives the motion and/or cycling of matter. The island of Iceland sits right on the Mid-Atlantic ridge (Figure below). Earths physical features occur in patterns, as do earthquakes and volcanoes. WebScience. Because oceanic crust is composed of rocks that are less dense than continental crust, it falls beneath it. The Southeast Indian Ridge is located in the Indian and Pacific Oceans. It is likely that as many as 20 mantle plumes, many of which still exist, were responsible for the initiation of the rifting of Pangaea along what is now the mid-Atlantic ridge. Lupton, J., 1998. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. The continuous mountain range is 65,000km (40,400mi) long (several times longer than the Andes, the longest continental mountain range), and the total length of the oceanic ridge system is 80,000km (49,700mi) long. 
Hydrothermal activity at the ridge crest is efficient in removing magnesium. The effect of unbalanced forces on an object results in a change of motion. Plus, get practice tests, quizzes, and personalized coaching to help you Plate boundaries with this type of structure are well-known, such as the Mid-Atlantic Ridge. Energy may take different forms (e.g. PS2.B Types of Interactions. There are three types of tectonic plate boundaries: subduction, convergent, and divergent. The plate collision at a constructive boundary can result in the formation of mountains. Dewey, W.F. [2][3][9][10] By contrast, fast-spreading ridges (greater than 90mm/yr) such as the East Pacific Rise lack rift valleys. In oceans, this happens at mid-ocean ridges -- on land, at continental rift zones. Subduction is also demonstrated by the presence of the Aleutian Islands. 
The mid ocean ridge is the longest mountain range on Earth. Mid-ocean ridges form at divergent plate boundaries, where seafloor spreading leads to the production of new ocean crust. The German Meteor expedition traced the mid-ocean ridge from the South Atlantic into the Indian Ocean early in the twentieth century. It is suggested that this type of valley eventually develops into a linear sea (such as the present-day Red Sea), and finally into an ocean (such as the Atlantic). The transfer of energy can be tracked as energy flows through a designed or natural system. Within this model, the geometry and location of mid-ocean ridges are considered to be independent of lower-mantle dynamics, such as deeply sourced plumes that produce voluminous lava eruptions-termed large igneous provinces. Certain features on Earth can be used to order events that have occurred in a landscape. What are some other interesting mid-ocean ridge facts? School of Geosciences, University of Sydney, Australia via NOAA's National Geophysical Data Center, Added on The mineralogy of reef-building and sediment-producing organisms is thus regulated by chemical reactions occurring along the mid-ocean ridge, the rate of which is controlled by the rate of sea-floor spreading. A section of the Mid-Atlantic Ridge located above water in Iceland. Get unlimited access to over 88,000 lessons. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. The crust and the relatively rigid peridotite below it make up the oceanic lithosphere, which sits above the less rigid and viscous asthenosphere. Two plates move away from each other in a constructive plate boundary. They also propose causal relationships by examining what is known about smaller scale mechanisms within the system. The spreading, however, is generally not uniform causing linear features perpendicular to the divergent boundaries. They can also design systems to do specific tasks. Find out what causes mid-ocean ridges and what happens at a mid-ocean ridge. Over time, as the plates continue to diverge, the magnetic polarity reverses, and new crust formed at the ridge now takes on the reversed polarity (white stripes in Figure \(\PageIndex{8}\)). Because the poles are closer to the center of the Earth than the equator, d2 and g will be smaller in Equation 7. Language links are at the top of the page across from the title. The mid-ocean ridge is nearly 60,000 kilometers, or 37,000 miles, in length. [31], Increased rates of seafloor spreading (i.e. They see some changes are irreversible, and negative feedback can stabilize a system, while positive feedback can destabilize it. Earthquakes occur as a result of this fracturing and movement. One of the constructive boundaries is one in which two plates do not collide and destroy any continental landmasses. [43] Soundings from lines dropped to the seafloor were analyzed by oceanographers Matthew Fontaine Maury and Charles Wyville Thomson and revealed a prominent rise in the seafloor that ran down the Atlantic basin from north to south. The tectonic plates are constantly in motion and new surfaces are always being created. There are multiple lines of evidence demonstrating that new oceanic crust is forming at these seafloor spreading centers: Comparing the ages of the oceanic crust near a mid-ocean ridge shows that the crust is youngest right at the spreading center, and gets progressively older as you move away from the divergent boundary in either direction, aging approximately 1 million years for every 20-40 km from the ridge. WebA convergent plate boundary is most likely associated with a (n): -oceanic trench. In nuclear processes, atoms are not conserved, but the total number of protons plus neutrons is conserved. It's the only place we can see a mid-ocean ridge out of the water. The spreading center or axis commonly connects to a transform fault oriented at right angles to the axis. [6] A good approximation is that the depth of the seafloor at a location on a spreading mid-ocean ridge is proportional to the square root of the age of the seafloor. The Himalayas can be seen here because of a collision between two continents: the Indo-Australian and Eurasian plates. This feature is where seafloor spreading takes place along a divergent plate boundary. Radioactive decay within Earths interior contributes to thermal convection in the mantle. Because of the ease with which new materials can be created, two types of boundaries are commonly referred to as divergent or constructive boundaries. Students learn that the total amount of energy and matter in closed systems is conserved. This is seafloor spreading. Convergent boundaries are also called collision boundaries because they are areas where two plates collide. New magma of basalt composition emerges at and near the axis because of decompression melting in the underlying Earth's mantle. Because of this, the youngest sea floor can be found along divergent boundaries, such as the Mid-Atlantic Ocean Ridge. [50] With a crustal thickness of 7km (4.3mi), this amounts to about 19km3 (4.6cumi) of new ocean crust formed every year. The rocks making up the crust below the seafloor are youngest along the axis of the ridge and age with increasing distance from that axis. Divergent plate boundaries in the ocean create mid-ocean ridges. By contrast, the East Pacific Rise has been characterized as a fast-spreading center, with as much as 6 to 16 centimeters, or 3-6 inches, of new ocean floor forming every year. As the oceanic plate cools, away from the ridge axis, the oceanic mantle lithosphere (the colder, denser part of the mantle that, together with the crust, comprises the oceanic plates) thickens, and the density increases. Causes of Glaciation: Overview & Theory | What is Glaciation? While many of these processes can be observed, other processes occur beneath the Earth's surface. [12] Ridges that spread at rates <20mm/yr are referred to as ultraslow spreading ridges[3][13] (e.g., the Gakkel Ridge in the Arctic Ocean and the Southwest Indian Ridge). [37] Hydrothermal vents at spreading centers introduce various amounts of iron, sulfur, manganese, silicon, and other elements into the ocean, some of which are recycled into the ocean crust. They can use models (e.g., physical, mathematical, computer models) to simulate the flow of energy, matter, and interactions within and between systems at different scales. Joanna holds a PhD in Biology from the University of Michigan and is currently working towards a degree in Veterinary Medicine at Michigan State University. A constructive plate boundary is where two plates are moving towards each other. Enrolling in a course lets you earn progress by passing quizzes and exams. Figure 15b depicts a theoretical density model. 31 chapters | b. the lithosphere is divided into plates. Why a photo of a bridge with some bleak looking rock? The plates pulling apart cause earthquakes. 
I would definitely recommend Study.com to my colleagues. The Southeast Indian Ridge is located between the Indo-Australian and Antarctic plates. This process leads to the creation of a new crust and the formation of underwater mountains along the extensive ridge. I feel like its a lifeline. the Mid At transform boundaries, the plates slide and grind past one another. 
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They also understand that phenomena may have more than one cause, and some cause and effect relationships in systems can only be described using probability. Divergent plate boundaries are locations where plates are moving away from one another. Most mid-ocean ridges are located deep below the sea. A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. [6] The overall shape of ridges results from Pratt isostacy: close to the ridge axis, there is a hot, low-density mantle supporting the oceanic crust. Seafloor spreading Seafloor global topography: cooling models, Plate tectonics Development of the theory, "What is the longest mountain range on earth? WebIn Earth's current lithospheric plate configuration, the mid-ocean ridge system extends connected for over 60,000 km making them also the longest mountain chain and plate The mid ocean ridge is the longest mountain range on Earth. Much like a hot spring on the ocean floor, hydrothermal vents occur where heated fluid is propelled through the Earth's crust. Some other interesting mid-ocean ridge facts include: Mid-ocean ridges represent a chain of underwater mountains formed by seafloor spreading at divergent plate boundaries. This magma oozes out onto the seafloor to form pillow basalts, breccias (fragmented basaltic rock), and flows, interbedded in some cases with limestone or chert. They understand events that occur together with regularity might or might not signify a cause and effect relationship. Volcanic activity sometimes occurs within the rift. G is measured in marine surveys at a lower rate than in land surveys, which are commonly referred to as free-air anomalies. This slow spreading ridge deposits new ocean crust at a rate of 2 to 5 centimeters, or 0.8 to 2 inches, per year. Concept note-5: -Most divergent boundaries are located along mid-ocean oceanic ridges (although some are on land). This new crust is formed due to igneous intrusions and extrusions as magma either cools beneath the Earth's surface or erupts as lava above the Earth's surface. Forces that act at a distance involve fields that can be mapped by their relative strength and effect on an object. In Iceland, the Mid-Atlantic Ridge is above sea level. Students can investigate or analyze a system by defining its boundaries and initial conditions, as well as its inputs and outputs. Because a majority of this mountain range is located below the ocean, few people have ever seen it up close, and many people don't know about this massive feature on Earth. Most divergent boundaries are located along mid-ocean oceanic ridges (although some are on land). Students learn some systems appear stable, but over long periods of time they will eventually change. Scientists named it the 'Mid-Atlantic Ridge'. This action creates mountains. 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The oldest oceanic crust is around 280 Ma in the eastern Mediterranean, and the oldest parts of the open ocean are around 180 Ma on either side of the north Atlantic. [17][18] Hydrothermal vents fueled by magmatic and volcanic heat are a common feature at oceanic spreading centers. The East Africa Rift is in a very early stage of development. Iceland is a location where we can see a mid-ocean ridge above sea level. WebThe first sort of plate boundary is called a divergent boundary, or spreading center. 1 April 2010. Two locations are marked within the rift valley of East Africa, and another location is marked within the Red Sea. A plate boundary is a location where the plates that are moving away from one another are so Divergent. An oceanographer will give you a far better response than I can, young lady. [25] In slab pull the weight of a tectonic plate being subducted (pulled) below an overlying plate at a subduction zone drags the rest of the plate along behind it. This type of boundary is also known as a spreading boundary. Maps can be used to locate features and determine patterns in those events. low topographic ridge in ocean basin oceanic trench no earthquakes shallow earthquakes only shallow and deep earthquakes underwater The Ridge is a high area compared to the surrounding seafloor because of the lift from the convection current below. They also learn within a natural or designed system, the transfer of energy drives the motion and/or cycling of matter. The island of Iceland sits right on the Mid-Atlantic ridge (Figure below). Earths physical features occur in patterns, as do earthquakes and volcanoes. WebScience. Because oceanic crust is composed of rocks that are less dense than continental crust, it falls beneath it. The Southeast Indian Ridge is located in the Indian and Pacific Oceans. It is likely that as many as 20 mantle plumes, many of which still exist, were responsible for the initiation of the rifting of Pangaea along what is now the mid-Atlantic ridge. Lupton, J., 1998. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. The continuous mountain range is 65,000km (40,400mi) long (several times longer than the Andes, the longest continental mountain range), and the total length of the oceanic ridge system is 80,000km (49,700mi) long. Hydrothermal activity at the ridge crest is efficient in removing magnesium. The effect of unbalanced forces on an object results in a change of motion. Plus, get practice tests, quizzes, and personalized coaching to help you Plate boundaries with this type of structure are well-known, such as the Mid-Atlantic Ridge. Energy may take different forms (e.g. PS2.B Types of Interactions. There are three types of tectonic plate boundaries: subduction, convergent, and divergent. The plate collision at a constructive boundary can result in the formation of mountains. Dewey, W.F. [2][3][9][10] By contrast, fast-spreading ridges (greater than 90mm/yr) such as the East Pacific Rise lack rift valleys. In oceans, this happens at mid-ocean ridges -- on land, at continental rift zones. Subduction is also demonstrated by the presence of the Aleutian Islands. The mid ocean ridge is the longest mountain range on Earth. Mid-ocean ridges form at divergent plate boundaries, where seafloor spreading leads to the production of new ocean crust. The German Meteor expedition traced the mid-ocean ridge from the South Atlantic into the Indian Ocean early in the twentieth century. It is suggested that this type of valley eventually develops into a linear sea (such as the present-day Red Sea), and finally into an ocean (such as the Atlantic). The transfer of energy can be tracked as energy flows through a designed or natural system. Within this model, the geometry and location of mid-ocean ridges are considered to be independent of lower-mantle dynamics, such as deeply sourced plumes that produce voluminous lava eruptions-termed large igneous provinces. Certain features on Earth can be used to order events that have occurred in a landscape. What are some other interesting mid-ocean ridge facts? School of Geosciences, University of Sydney, Australia via NOAA's National Geophysical Data Center, Added on The mineralogy of reef-building and sediment-producing organisms is thus regulated by chemical reactions occurring along the mid-ocean ridge, the rate of which is controlled by the rate of sea-floor spreading. A section of the Mid-Atlantic Ridge located above water in Iceland. Get unlimited access to over 88,000 lessons. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. The crust and the relatively rigid peridotite below it make up the oceanic lithosphere, which sits above the less rigid and viscous asthenosphere. Two plates move away from each other in a constructive plate boundary. They also propose causal relationships by examining what is known about smaller scale mechanisms within the system. The spreading, however, is generally not uniform causing linear features perpendicular to the divergent boundaries. They can also design systems to do specific tasks. Find out what causes mid-ocean ridges and what happens at a mid-ocean ridge. Over time, as the plates continue to diverge, the magnetic polarity reverses, and new crust formed at the ridge now takes on the reversed polarity (white stripes in Figure \(\PageIndex{8}\)). Because the poles are closer to the center of the Earth than the equator, d2 and g will be smaller in Equation 7. Language links are at the top of the page across from the title. The mid-ocean ridge is nearly 60,000 kilometers, or 37,000 miles, in length. [31], Increased rates of seafloor spreading (i.e. They see some changes are irreversible, and negative feedback can stabilize a system, while positive feedback can destabilize it. Earthquakes occur as a result of this fracturing and movement. One of the constructive boundaries is one in which two plates do not collide and destroy any continental landmasses. [43] Soundings from lines dropped to the seafloor were analyzed by oceanographers Matthew Fontaine Maury and Charles Wyville Thomson and revealed a prominent rise in the seafloor that ran down the Atlantic basin from north to south. The tectonic plates are constantly in motion and new surfaces are always being created. There are multiple lines of evidence demonstrating that new oceanic crust is forming at these seafloor spreading centers: Comparing the ages of the oceanic crust near a mid-ocean ridge shows that the crust is youngest right at the spreading center, and gets progressively older as you move away from the divergent boundary in either direction, aging approximately 1 million years for every 20-40 km from the ridge. WebA convergent plate boundary is most likely associated with a (n): -oceanic trench. In nuclear processes, atoms are not conserved, but the total number of protons plus neutrons is conserved. It's the only place we can see a mid-ocean ridge out of the water. The spreading center or axis commonly connects to a transform fault oriented at right angles to the axis. [6] A good approximation is that the depth of the seafloor at a location on a spreading mid-ocean ridge is proportional to the square root of the age of the seafloor. The Himalayas can be seen here because of a collision between two continents: the Indo-Australian and Eurasian plates. This feature is where seafloor spreading takes place along a divergent plate boundary. Radioactive decay within Earths interior contributes to thermal convection in the mantle. Because of the ease with which new materials can be created, two types of boundaries are commonly referred to as divergent or constructive boundaries. Students learn that the total amount of energy and matter in closed systems is conserved. This is seafloor spreading. Convergent boundaries are also called collision boundaries because they are areas where two plates collide. New magma of basalt composition emerges at and near the axis because of decompression melting in the underlying Earth's mantle. Because of this, the youngest sea floor can be found along divergent boundaries, such as the Mid-Atlantic Ocean Ridge. [50] With a crustal thickness of 7km (4.3mi), this amounts to about 19km3 (4.6cumi) of new ocean crust formed every year. The rocks making up the crust below the seafloor are youngest along the axis of the ridge and age with increasing distance from that axis. Divergent plate boundaries in the ocean create mid-ocean ridges. By contrast, the East Pacific Rise has been characterized as a fast-spreading center, with as much as 6 to 16 centimeters, or 3-6 inches, of new ocean floor forming every year. As the oceanic plate cools, away from the ridge axis, the oceanic mantle lithosphere (the colder, denser part of the mantle that, together with the crust, comprises the oceanic plates) thickens, and the density increases. Causes of Glaciation: Overview & Theory | What is Glaciation? While many of these processes can be observed, other processes occur beneath the Earth's surface. [12] Ridges that spread at rates <20mm/yr are referred to as ultraslow spreading ridges[3][13] (e.g., the Gakkel Ridge in the Arctic Ocean and the Southwest Indian Ridge). [37] Hydrothermal vents at spreading centers introduce various amounts of iron, sulfur, manganese, silicon, and other elements into the ocean, some of which are recycled into the ocean crust. They can use models (e.g., physical, mathematical, computer models) to simulate the flow of energy, matter, and interactions within and between systems at different scales. Joanna holds a PhD in Biology from the University of Michigan and is currently working towards a degree in Veterinary Medicine at Michigan State University. A constructive plate boundary is where two plates are moving towards each other. Enrolling in a course lets you earn progress by passing quizzes and exams. Figure 15b depicts a theoretical density model. 31 chapters | b. the lithosphere is divided into plates. Why a photo of a bridge with some bleak looking rock? The plates pulling apart cause earthquakes. I would definitely recommend Study.com to my colleagues. The Southeast Indian Ridge is located between the Indo-Australian and Antarctic plates. This process leads to the creation of a new crust and the formation of underwater mountains along the extensive ridge. I feel like its a lifeline. the Mid At transform boundaries, the plates slide and grind past one another. Book: Introduction to Oceanography (Webb), { "4.01:_Alfred_Wegener_and_the_Theory_of_Plate_Tectonics" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.