Facts about the Divergent Plate Boundary
- It is also called a constructive boundary, as a new crust is formed at this plate boundary.
- Tectonic plates move slowly and steadily. The ridge spreads or widens by a few centimeters every year.
- The sea floor spreading results in the formation of parallel sea mounts or even bigger mountains on the ocean floor.
What does it mean if a plate boundary is divergent?
Divergent plate boundaries occur when two plates separate from each other. Divergent plate boundaries form the Mid Atlantic Ridge, the largest underwater mountain range. There are several types of landforms that are created from divergent plate boundaries including rift valleys, oceanic trenches, and underwater mountain ranges.
What happens to plates in a divergent boundary?
When the movement of the tectonic plates causes two plates to pull away from each other, a divergent boundary is said to exist. Divergent boundaries that develop in the ocean lead to the creation of mountains and volcanoes, according to the National Geographic.
What are the features of a divergent plate boundary?
The beneath area of divergent plate boundary often features the material due to the complex convection in the mantle of earth. When the two opposing plates are moving away from each other, the gap will be filled. It happens during the eruption. The tectonic plates will shift from the sides of divergent plate boundary.
What happens at a divergent plate boundary?
Divergent plate boundaries are locations where plates are moving away from one another. This occurs above rising convection currents. The rising current pushes up on the bottom of the lithosphere, lifting it and flowing laterally beneath it. This lateral flow causes the plate material above to be dragged along in the direction of flow.
What are 2 examples of divergent boundaries?
Divergent boundaries are typified in the oceanic lithosphere by the rifts of the oceanic ridge system, including the Mid-Atlantic Ridge and the East Pacific Rise, and in the continental lithosphere by rift valleys such as the famous East African Great Rift Valley.
What does a divergent plate boundary look like?
0:002:25Two types of Divergent Plate Boundaries - YouTubeYouTubeStart of suggested clipEnd of suggested clipThere are two major types of divergent boundaries continental and continental lithosphere andMoreThere are two major types of divergent boundaries continental and continental lithosphere and oceanic.
What type of rocks are formed at divergent boundaries?
Felsic and intermediate magmas and rocks tend to form at ocean--continent or ocean--ocean convergent boundaries, or where hot spots are found on land, and mafic magmas form in divergent plate boundaries and hot spots in the ocean.
Do divergent boundaries cause volcanoes?
Plates rip apart at a divergent plate boundary, causing volcanic activity and shallow earthquakes; and. At a convergent plate boundary, one plate dives or “subducts” beneath the other, resulting in a variety of earthquakes and a line of volcanoes on the overriding plate.
Where would one find a convergent plate boundary?
Convergent boundaries occur between oceanic-oceanic lithosphere, oceanic-continental lithosphere, and continental-continental lithosphere. The geologic features related to convergent boundaries vary depending on crust types.
What do divergent plates create?
A divergent boundary occurs when two tectonic plates move away from each other. Along these boundaries, earthquakes are common and magma (molten rock) rises from the Earth's mantle to the surface, solidifying to create new oceanic crust.
What types of rocks are found at convergent plate boundaries?
Metamorphic rocks are most abundant at convergent plate boundaries, but can occur in other areas where there are increased pressures and/or temperatures. Sedimentary rocks form only on the surface of the Earth.
Which type of metamorphism is found at a divergent plate boundary?
Contact metamorphism is common at both convergent and divergent plate boundaries, in areas where molten rock is produced. Regional metamorphism largely occurs at convergent plate boundaries.
Where are divergent plate boundaries on Earth?
Perhaps the best known of the divergent boundaries is the Mid-Atlantic Ridge. This submerged mountain range, which extends from the Arctic Ocean to beyond the southern tip of Africa, is but one segment of the global mid-ocean ridge system that encircles the Earth.
What does a divergent boundary form on land?
A divergent plate boundary on land rips apart continents (Figure below). When plate divergence occurs on land, the continental crust rifts, or splits. This effectively creates a new ocean basin as the pieces of the continent move apart.
What features are found at convergent boundaries?
Effects found at a convergent boundary between continental plates include: intense folding and faulting; a broad folded mountain range; shallow earthquake activity; shortening and thickening of the plates within the collision zone.
What does a convergent boundary form?
Convergent boundaries can form mountains, volcanos, or subduction zones that form large trenches. When two plates collide, the crusts can push together to form mountain ranges. This is how the Himalayan mountains were formed. Convergent boundaries between oceanic and continental boundaries feature a subduction zone.
What causes valley floors to drop down along fault lines in the Basin and Range Province?
Continental rifting causes valleys floors to drop down along fault lines in the Basin and Range Province. Snake Valley, Tucson Basin and Death Valley are the basins, while the Snake Range, Rincon Mountains, Tucson Mountains and Panamint Mountains are the adjacent ranges.
Which crust sticks up above sea level?
Continental crust is thick and buoyant, and therefore sticks up above sea level.
What is the rift zone?
Where tectonic plates move away from one another the lithosphere thins. The underlying asthenosphere rises and expands like a hot-air balloon, elevating a broad region. If the plate is capped by thick continental crust, the resulting continental rift zone rises high above sea level. The Basin and Range Province is thus a high-elevation region that includes all of Nevada and portions of Wyoming, Utah, California, and Arizona, and extends into southern Oregon, Idaho, and Montana. It is similar to the East African Rift, where volcanic materials and sedimentary layers deposited by rivers and lakes partially fill rift valleys. Prominent planar surfaces (fault escarpments) along range fronts are evidence that the region continues to rip apart—erosion would smooth them out if the fault movement stopped. The Rio Grande Rift is an arm of the Basin and Range Province extending across westernmost Texas, New Mexico, and southern Colorado. Earthquakes, fault-block mountains, and volcanism at Guadalupe Mountains National Park and Bandelier and White Sands national monuments are consequences of the ongoing continental rifting.
What are the effects of continental rifting?
The same continental rifting processes that form the high-elevation valleys and mountain ranges of the Basin and Range Province and Rio Grande Rift also result in earthquakes and volcanic activity. As the lithosphere pulls apart and thins, the underlying, hot asthenosphere rises and expands like a hot-air balloon, elevating the entire region. The drop in pressure on the shallow asthenosphere makes it start to melt. Some of the liquid rock (magma) makes it to the surface and forms lava flows, shield volcanoes, cinder cones, and other volcanic features.
Why does magma become rich in silica?
The magma becomes enriched in silica because high-silica minerals tend to melt first. Some of the lava that initially pours out at continental rift zones is thus thick and pasty, cooling to light-colored rocks (rhyolite and dacite), and steep-sided lava domes and composite volcanoes.
What is the topography of the Rio Grande Rift?
The high elevations (brown shading) and rugged topography of the Basin and Range Province and Rio Grande Rift, which are actively forming can be seen in the shaded relief map, below. The Keweenwan Rift has sedimentary and volcanic rock layers similar to those found in the active rifts, but its topography is subdued because it formed over a billion years ago.
What is the topography of the Basin and Range Province and Rio Grande Rift?
The topography of the Basin and Range Province and Rio Grande Rift reveals the full range of characteristics of a continental rift zone. First, much of the region—particularly the northern portion—is well above sea level.
Where are divergent boundaries found?
The vast majority of divergent boundaries are found in the ocean, where they were not mapped or understood until the mid-to-late 20th century.
Which oceans are examples of continental divergence?
A much better example of how continental divergence creates oceans is easy to see in the South Atlantic Ocean . There, the precise fit between South America and Africa testifies to the fact that they were once integrated with a larger continent.
Why do ridges have steeper sides?
Slow-spreading ridges like the Mid-Atlantic Ridge have steeper-sloping sides because it takes less distance for their new lithosphere to cool. They have relatively little magma production so that the ridge crest can develop a deep dropped-down block, a rift valley, at its center.
Why is the fresh seafloor higher than the older lithosphere?
At oceanic divergent boundaries, new lithosphere is born hot and cools over millions of years. As it cools it shrinks, thus the fresh seafloor stands higher than the older lithosphere on either side. This is why divergent zones take the form of long, wide swells running along the ocean floor: mid-ocean ridges. The ridges are only a few kilometers high but hundreds wide.
What did the study of mid ocean ridges help establish?
The study of mid-ocean ridges helped establish the theory of plate tectonics in the 1960s. Geomagnetic mapping showed large, alternating "magnetic stripes" in the seafloor, a result of Earth's ever-changing paleomagnetism. These stripes mirrored each other on both sides of divergent boundaries, giving geologists irrefutable evidence of seafloor spreading.
What is the slope of a ridge?
The ridges are only a few kilometers high but hundreds wide. The slope on the flanks of a ridge means that diverging plates get an assist from gravity, a force called "ridge push" that, together with slab pull, accounts for most of the energy driving the plates. On the crest of each ridge is a line of volcanic activity.
What happens to the hot mantle rock in divergent zones?
In divergent zones, this pulling motion uncovers the hot deep mantle rock of the asthenosphere. As the pressure eases on the deep rocks, they respond by melting, even though their temperature may not change.
What is divergent boundary?
A divergent boundary is a place where the convection currents in the mantle move upwards. This upwelling of magma splits and push the earth's crust apart.
What causes rift valleys?
Rift valleys like that of East Africa are also thought be be caused by divergent plate boudoirs. A rift valley is a place where the crust is splitting apart. The weak spot in the crust caused by the movement of mantle under neath causes new oceans and lakes to from along the divergent boundary. Also volcanos are formed like Mount Kenya.
Why do divergent plates grow at the oceanic crust?
Because divergent plates fill in the gaps with basalt, the oceanic crust turns out to be very young geologically. Over time, the plates grow at the oceanic crust and older rock is pushed away from mid-oceanic ridges.
Where do plate tectonics begin?
Plate tectonics begin at mid-oceanic ridges where plates are moving apart. Because plates pull apart from each other at divergent plates, lava spews out to create the youngest geological rocks on Earth.
What type of plate pulls apart from each other?
Divergent plate tectonics pull apart from each other producing rift valleys at mid-oceanic ridges.
Why does magma flow upwards from the mantle?
Because divergent plates move apart from each other at these mid-oceanic ridges, magma flows upwards from the mantle beneath.
Which plate boundary runs for most of the length of the Atlantic Ocean?
ATLANTIC OCEAN: A divergent plate boundary runs for most of the length of the Atlantic Ocean. This is the longest divergent plate on the planet.
How many kilometers of volcanoes are there under the ocean?
Beneath the oceans, lava erupts every day. Because it’s all underground, we don’t realize it’s even happening. Actually, the Earth has 70,000 km of continuous volcanoes under the ocean. More specifically, the volcanoes are at mid-oceanic ridges.
What is a divergent plate boundary?
A divergent plate boundary often forms a mountain chain known as a ridge . This feature forms as magma escapes into the space between the spreading tectonic plates. One example of a ridge is the Mid-Atlantic Ridge, an undersea chain of mountains that formed as two pairs of tectonic plates spread apart: the North American Plate and the Eurasian Plate in the north, and the South American Plate and the African Plate in the south. Because ocean ridges are found underwater, often at great depths, they can be hard to study. In fact, scientists know more about the surfaces of some of the other planets in our solar system than they do about ocean ridges.
Which plate boundary is responsible for many earthquakes?
A well-known transform plate boundary is the San Andreas Fault, which is responsible for many of California’s earthquakes. A single tectonic plate can have multiple types of plate boundaries with the other plates that surround it. For instance, the Pacific Plate, one of Earth’s largest tectonic plates, includes convergent, divergent, ...
What is the boundary between the Indian Plate and the Eurasian Plate?
Typically, a convergent plate boundary —such as the one between the Indian Plate and the Eurasian Plate—forms towering mountain ranges, like the Himalaya, as Earth’s crust is crumpled and pushed upward. In some cases, however, a convergent plate boundary can result in one tectonic plate diving underneath another.
Why are volcanoes found near plate boundaries?
Volcanoes are also often found near plate boundaries because molten rock from deep within Earth—called magma—can travel upward at these intersections between plates . There are many different types of plate boundaries. For example, sections of Earth’s crust can come together and collide (a “convergent” plate boundary), ...
Why are plate boundaries important?
Plate boundaries are important because they are often associated with earthquakes and volcanoes. When Earth’s tectonic plates grind past one another, enormous amounts of energy can be released in the form of earthquakes. Volcanoes are also often found near plate boundaries because molten rock from deep within Earth—called magma—can travel upward ...
What is the area where two or more tectonic plates bump into each other?
area where two or more tectonic plates bump into each other. Also called a collision zone.
Why are ocean ridges so hard to study?
Because ocean ridges are found underwater, often at great depths, they can be hard to study. In fact, scientists know more about the surfaces of some of the other planets in our solar system than they do about ocean ridges. A transform plate boundary occurs when two plates slide past each other, horizontally.
What is transform plate boundary?
Transform plate boundaries are where plates slide laterally past one another, producing shallow earthquakes but little or no volcanic activity. Another large-scale feature is a hotspot, where a plate rides over a rising plume of hot mantle, creating a line of volcanoes on top of the plate.
What are the three types of tectonic plates?
The landscapes of our national parks, as well as geologic hazards such as earthquakes and volcanic eruptions, are due to the movement of the large plates of Earth’s outer shell.#N#There are three types of tectonic plate boundaries: 1 Plates rip apart at a divergent plate boundary, causing volcanic activity and shallow earthquakes; 2 At a convergent plate boundary, one plate dives (“subducts”) beneath the other, resulting in a variety of earthquakes and a line of volcanoes on the overriding plate; 3 Transform plate boundaries are where plates slide laterally past one another, producing shallow earthquakes but little or no volcanic activity.
What happens when a plate rips apart?
Plates rip apart at a divergent plate boundary, causing volcanic activity and shallow earthquakes; At a convergent plate boundary, one plate dives (“subducts”) beneath the other, resulting in a variety of earthquakes and a line of volcanoes on the overriding plate;
What happens when two plates crash together?
Where plates crash together, one dives (“ subducts”) beneath the other, causing volcanoes (red triangles) to erupt on the overriding plate and earthquakes (black stars) at a variety of depths. The large white star represents the zone where plates lock together for centuries then suddenly let go, causing the largest earthquakes.
How fast do the plates move?
For example, moving at about 2 inches (5 centimeters) per year , in our lifetime the Pacific Plate moves 10 to 15 feet (3 - 5 meters) past the North American Plate along the San Andreas Fault, a transform plate boundary in California. As Europe and Africa move away from North and South America at about 1½ inches (4 centimeters) per year, the Atlantic Ocean has opened to a width of 4,000 miles (6,000 kilometers) in the past 150 million years!
