The physical landscape was an important component of the practical and spiritual aspects of Native Americans lives. There is strong evidence around the margins of the Atlantic Ocean that this process has taken place before. Observations. All volcanic eruptions in Iceland, such as the 1973 eruption of Eldfell, the 1783 eruption of Laki, and the 2010 eruption of Eyjafjallajkull, are caused by the North American and the Eurasian Plates moving apart, which is a result of divergent plate boundary forces. In 1989 and 1990, Mt. Sandstone and shale layers at Kenai Fjords are commonly metamorphosed and were so deformed during subduction and uplift that they are vertical in places. Within the past few million years, rifting has taken place in the Gulf of Aden and the Red Sea, and also within the Gulf of California. Cocos Plate; Type: Minor: Approximate area: 2,900,000 km 2: Movement 1: north-east: Speed 1: 67 mm/year: . Novarupta Lava Dome The mountain is mainly andesite lava flows and volcanic mudflows covered by numerous glaciers. The Cocos Plate is subducting beneath the Caribbean Plate, while the Caribbean Plate is subducting below both the Panama Plate and the North Andean Plate. The Cascadia Subduction Zone, extending from northern California through western Oregon and Washington to southern British Columbia, is a type of convergent plate boundary. This plate is moving north north east towards the Eurasia plate. The Cocos Plate was created approximately 23 million years ago when the Farallon Plate broke into two pieces, which also created the Nazca Plate. Farther east the Juan de Fuca Plate descends deeper and deeper. The types are ocean-ocean, ocean-continent, and continent-continent. USGS photo. * The boundaries that moving away . Over the next 50 million years, it is likely that there will be full development of the east African rift and creation of new ocean floor. The eastern boundary is a transform fault, the Panama Fracture Zone. North America plate, Africa plate, Australia plate, Arabia plate, India plate, Filipino plate. Elias National Park What are the 4 types of plate boundaries? Lake Clark National Park and Preserve contains an active composite volcano with a profile and recent history reminiscent of Mt. Between 200 and 150 Ma, rifting started between South America and Africa and between North America and Europe, and India moved north toward Asia. That may not seem like much, but when tens of thousands of earthquakes occur over a few million years, coastal ranges form. Mount Rainier National Park showcases a 14,411-foot (4,393-meter) composite volcano. By 80 Ma, Africa had separated from South America, most of Europe had separated from North America, and India had separated from Antarctica. Before we talk about processes at plate boundaries, its important to point out that there are never gaps between plates. The northern side is a divergent boundary with the Cocos Plate, the Galapagos Rise. Examples of ocean-ocean convergent zones are subduction of the Pacific Plate beneath the North America Plate south of Alaska (Aleutian Islands) and beneath the Philippine Plate west of the Philippines, subduction of the India Plate beneath the Eurasian Plate south of Indonesia, and subduction of the Atlantic Plate beneath the Caribbean Plate (see Figure \(\PageIndex{1}\)). Illustrations above modified from Earth: Portrait of a Planet", by S. Marshak, 2001, W. W. Norton & Comp., New York. Basalt lava is thin and runny and will flow for miles and miles. This plate includes all of Africa and the surrounding ocean, including the eastern Atlantic Ocean, the surrounding Antarctic Ocean, and the western Indian ocean. The North American plate is moving to the west-southwest at about 2.3 cm (~1 inch) per year driven by the spreading center that created the Atlantic Ocean, the Mid Atlantic Ridge. Roughly 3.2 million square kilometers (1.2 million square miles) in area, the Caribbean. It is likely that as many as 20 mantle plumes, many of which still exist, were responsible for the initiation of the rifting of Pangea along what is now the mid-Atlantic ridge (see Figure \(\PageIndex{10}\)). . Cocos Tectonic Plate Aniakchak National Monument and Preserve is on the Alaska Peninsula. Forty million years ago, a large tectonic plate, known as the Farallon Plate, was between the Pacific and North American plates. As the Juan de Fuca Plate (lower cookie) subducts beneath the North American Plate (upper cookie), the layers are scraped off the ocean floor and pile up as the Coast Range. As discussed in the context of subduction-related volcanism in Chapter 4, the significant volume of water within the subducting material is released as the subducting crust is heated. Mazama that formed Crater Lake. Kenai Fjords National Park CC BY. The Cocos Plate Examine the interactive globe. The Cocos Plate is a young oceanic tectonic plate beneath the Pacific Ocean off the west coast of Central America, named for Cocos Island, which rides upon it. and Alberta are also a result of continent-continent collisions. Introduction The Cocos Plate is a relatively small sized, triangular-shaped oceanic plate located just west of Mexico and the Caribbean. When mixed with water from glaciers, snowmelt, and streams, these materials can make very dense, fast-moving volcanic mudflows (known sometimes by the Indonesian term lahar). In 1966, Tuzo Wilson proposed that there has been a continuous series of cycles of continental rifting and collision; that is, break-up of supercontinents, drifting, collision, and formation of other supercontinents. Magmas high in silica are thick and pasty. The original composite volcano was about 7,000 feet (2,000 meters) high, but lost about 2,500 feet (750 meters) of its height. Adding TravelTime as Impedance in ArcGIS Network Analyst? Massive areas of granite from the cooled magma chambers that fed the volcanoes form portions of the Sierra Nevada Mountains, including Yosemite National Park. We know that the JDF Plate is moving toward the North American Plate at around 4 centimeters per year to 5 centimeters per year. Because the oceanic crust formed by spreading on the mid-Atlantic ridge is not currently being subducted (except in the Caribbean), the Atlantic Ocean is slowly getting bigger, and the Pacific Ocean is getting smaller. The Cascades are the modern volcanic arc developing where the Juan de Fuca Plate subducts beneath the North American Plate. Copalis River, Washington Mazama, erupted and collapsed 7,700 years ago, forming the large cavity (caldera) that now holds Crater Lake. This is what has happened in the Sierra Nevada of central and southern California, as represented by the granite-type rocks of Half Dome within Yosemite National Park shown on the California state quarter. The lake partially fills a collapsed crater (caldera) that formed when a 12,000-foot (3,700-meter) composite volcano, Mt. These mega-earthquakes occur every 200 to 600 years or so, and the last one was in the year 1700. The resulting magmas can therefore have a variety of compositions, ranging from the original (low-silica) basalt, to (intermediate-silica) andesite, all the way up to (high-silica) rhyolite. Layers of sandstone and shale deposited on the top of the Pacific Plate were later metamorphosed to quartzite and slate as the plate subducted beneath southern Alaska, and then shoved upward as part of the accretionary wedge. Regional tectonics of Central America are mainly controlled by the collision of the Cocos and the Caribbean plates. This map shows the Juan de Fuca (JDF) and Explorer Plates off the coast of Vancouver Island. Where tectonic plates converge, the one with dense, thin oceanic crust subducts beneath the one with thick, more buoyant continental crust. This situation may not continue for too much longer, however. Examine the figure below. The forearc basin is the Willamette Valley in Oregon and Puget Sound in Washington. See Appendix 3 for Exercise 10.5 answers. Among them are Mt. NPS photo. Lassen Peak in Lassen Volcanic National Park is an amalgamation of rhyolite lava domes. In this region, the Cocos Plate is subducting beneath the North America and Caribbean Plates (ocean-continent convergence), and the South and North America Plates are subducting beneath the Caribbean Plate (ocean-ocean convergence). The rising hot water causes overlying rock to melt, generating magma that at times erupts out on the surface as lava flows and other materials forming Mt. Modified from Parks and Plates: The Geology of our National Parks, Monuments and Seashores, by Robert J. Lillie, New York, W. W. Norton and Company, 298 pp., 2005, www.amazon.com/dp/0134905172. After a terrifying free-fall that lasted 8 minutes, the pilots finally managed to restart the engines at only 6,000 feet (2,000 meters). Question: Tectonic Plates Use this map to answer the following questions. Many National Park Service sites are found in active and ancient subduction zones. Effects of the 1964 earthquake are quite spectacular in the park; the coastline dropped so much that in places it lies submerged beneath about 8 feet (2.5meters) of water. The three West Coast states are especially meaningful because they have geologic features that, when the quarters are stacked, represent the surface and subsurface of the chain of volcanoes that has been developing over the past 200 million years. Some of the resulting magma makes it all the way to the surface and forms Mount Rainier, Mount Hood, Mount Shasta and other spectacular volcanoes of the Cascade Range. The southern boundary is a mid-oceanic ridge, the Galapagos Rise. St. Helens, a lava dome later grew within the breached crater near the mountains summit. Without referring to the plate map in Figure \(\PageIndex{1}\), or any other resources, write in the names of as many of the plates as you can. The fact that the plates include both crustal material and lithospheric mantle material makes it possible for a single plate to be made up of both oceanic and continental crust. As the mid-ocean ridge separating the Farallon and Pacific Plates entered the subduction zone, the Farallon Plate separated into the Juan de Fuca and Cocos Plates. Poking through the mass of some of the highest mountains in North America are very young volcanoes formed by the ongoing Pacific Plate subduction. Pillow lavas form on the ocean floor where erupting magma encounters cold sea water. As they were caught in the vise between the converging Juan de Fuca and North American plates, some of the layers were so contorted that they are now in vertical orientations along the coast. As described above in the context of Benioff zones (Figure \(\PageIndex{6}\)), earthquakes take place close to the boundary between the subducting crust and the overriding crust. The eastern margins of North and South America and the western margins of Europe and Africa are called passive margins because there is no subduction taking place along them. Near the western edge of the continent, the Juan de Fuca Plate plunges downward and some of the layers of hard crust and ocean sediments are scraped off the top and squeezed upward as the Olympic Mountains and other coastal ranges. Australia plate, Eurasia plate, Africa plate, Arabia plate. Mazama, Aniakchak spewed lava across its caldera floor for centuries after its collapse. Redoubt, an active volcano in Lake Clark National Park, illustrates how a volcano can pose an unexpected hazard in our modern age and why monitoring volcanic activity is so important (see photo below). Photo courtesy of Robert J. Lillie. There is commonly an ocean trench along the boundary. It separates the Pacific Plate to the west from (north to south) the North American Plate, the Rivera Plate, the Cocos Plate, the Nazca Plate, and the Antarctic Plate. Pangea began to rift apart along a line between Africa and Asia and between North America and South America at around 200 Ma. The magma, which is lighter than the surrounding mantle material, rises through the mantle and the overlying oceanic crust to the ocean floor where it creates a chain of volcanic islands known as an island arc. Credit: Photo courtesy of Robert J. Lillie. Are transform boundaries continental or oceanic? This plate includes India and the surrounding India Ocean. Plates move as rigid bodies, so it may seem surprising that the North American Plate can be moving at different rates in different places. In her version of the Oreo cookie demonstration, the creamy filling is the layers of sediment and basalt on the ocean floor. We think that the Explorer Plate is also moving east, but we dont know the rate, and there is evidence that it is slower than the JDF Plate. Trees along the Washington coast were killed by salt-water invasion when the land suddenly dropped during the last great Cascadia Subduction Zone earthquake in the year 1700. The explanation is that plates move in a rotational manner. In the past, that was true. Tilted layers of thick sandstone (pink) and thin shale (dark) along the coast at Olympic National Park reveal the enormous forces that lifted and deformed the oceanic layers as the Juan de Fuca and North American plates converged. The Caribbean plate is sandwiched between the North American and South American plates to the east and the Cocos, Nazca and North Andean plates to the west. The Caribbean Plate is a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea off the northern coast of South America . The map shows the major tectonic plates that compose Earth's crust and upper mantle Arrows indicate direction of plate movement and the size of the arrows indicate rate of movement. Nazca plate, Pacific plate, North America plate, Caribbean plate. Pacific plate, Australia plate, Africa plate, Scotia plate, Nazca plate, South America plate. Likewise, individual volcanic eruptions may add only a thin layer to the surface. Accessibility StatementFor more information contact us atinfo@libretexts.org. 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Most of this water is present within the sheet silicate mineral serpentine which is derived from alteration of pyroxene and olivine near the spreading ridge shortly after the rocks formation. The Sierra Nevada are a remnant of volcanoes that extended southward when the ancient Farallon Plate dove beneath the edge of North America. The Nazca plate is a large tectonic plate that underlies the Pacific Ocean near the western coast of South America. The triangular zone of partial melting near the ridge crest is approximately 60 km thick and the proportion of magma is about 10% of the rock volume, thus producing crust that is about 6 km thick. This plate is small. The part of the plate around the South America plate is moving northwards and a little east. Crater Lake partially fills the caldera of a volcano that erupted and collapsed in on Itself 7,700 years ago. But the incident highlighted the importance of monitoring volcanic activity and making the information immediately available to the airline industry and other segments of the public. rare Examine the interactive globe. Taiwan area is the collision boundary between the Philippine Sea plate and the Eurasia plate, which has complex interaction, attracting much attention[3033]. The apparent line of collision runs between Norway and Sweden, between Scotland and England, through Ireland, through Newfoundland, and the Maritimes, through the northeastern and eastern states, and across the northern end of Florida. Now suppose the subduction processes that form the volcanoes were to stop, shutting off the magma supply that feeds the volcanoes. This is why some of the mountain chains formed during the earlier collision can be traced from Europe to North America and from Europe to Africa. The water rises and melts rock in its path. This highly active convergent plate boundary extends along both sides the Philippine Islands, from Luzon in the north to the Celebes Islands in the south. This plate includes Australia and much of the surrounding ocean. As the basalt magma rises up through the thick continental crust of North America, it melts some of that rock, too. It formed millions of years ago when the Farallon Plate split into the Cocos Plate and the Nazca Plate.. MORB Mid ocean ridge basalt subduction zones . The Coast Ranges, including the Olympic Mountains, are made of oceanic sediments and hard rocks that were caught in the vise between the converging plates, uplifted, and added to the edge of the continent. Would you characterize earthquake activity as. With continued uplift and erosion, most of the volcanic material would erode. The Coast Range and Cascades are the two parallel mountain ranges that form the Cascadia Subduction Zone in the Pacific Northwest. Fortunately, no one was injured. Californias San Andreas fault is a transform boundary. They are part of the volcanic arc that extends northeastward from the Aleutian Islands, across the Alaska Peninsula and Aniakchak National Monument, Katmai and Lake Clark national parks, and then bends eastward to Wrangell-St. Elias National Park. Dramatic examples of these layers in tilted and contorted forms can be found in Olympic National Park and elsewhere along the coast and in the mountains. The collapse caldera from the Katmai eruption is about 3 miles (5 kilometers) across and 2,000 feet (600 meters) deep. Some of the processes taking place in this setting include: Spreading is hypothesized to start within a continental area with up-warping or doming related to an underlying mantle plume or series of mantle plumes. Most divergent boundaries are located at the oceanic ridges (although some are on land), and the crustal material created at a spreading boundary is always oceanic in character; in other words, it is mafic igneous rock (e.g., basalt or gabbro, rich in ferromagnesian minerals). And at times, lower-silica components of their magma chambers erupt, producing basalt lava flows as well as cinders and volcanic bombs. The resulting magma ascends through the crust, producing a mountain chain with many volcanoes. What plate boundary is the Philippines and Eurasian Plate? At transform boundaries lithosphere is neither created nor destroyed. Wrangell, a 14,163 foot (4,317 meter) volcano that last erupted during the early part of the 20th Century. An ancient volcano, Mt. Find the plate boundary between the Juan de Fuca Plate (JF) and the North American Plate (NA). View the full answer. Along much of the boundary, the bulk of the motion occurs along the San Andreas Fault. Cocos Island rides on it.. This plate includes all of Saudi Arabia, and much of the Levant (up to Iraq and Syria). Modified from Beauty from the Beast: Plate Tectonics and the Landscapes of the Pacific Northwest, by Robert J. Lillie, Wells Creek Publishers, 92 pp., 2015, www.amazon.com/dp/1512211893. Another divergent plate boundary is the East Pacific Rise, which separates the massive Pacific plate from the Nazca, Cocos, and North American plates. During the same period, the Atlantic Ocean began to open up between northern Africa and North America, and India broke away from Antarctica. (Click on arrows and slide left and right to see labels.). Silica-rich ash melted and coated the hot engine turbines with glass, causing all four of them to shut down. The Coast Range (accretionary wedge), Great Valley (forearc basin), and Sierra Nevada (volcanic arc) still reflect the subduction zone topography. The plate boundary is a broad zone of deformation with a width of about 60 miles (100 kilometers). It is subducting under (that is, being forced under) the South American plate. What caused the Chile earthquake of 1960? This can be demonstrated by stacking the three quarters with California on the bottom, overlain by Oregon and then Washington. The caldera has partially filled with water an approximately half-scale version of the better-known Crater Lake in Oregon. Most divergent boundaries are located along mid-ocean oceanic ridges (although some are on land). The most famous example of a transform boundary is the San Andreas Fault in California. A convergent plate boundary is a location where two tectonic plates are moving toward each other, often causing one plate to slide below the other (in a process known as subduction). Now you should see color coded lines that are the plate boundaries, and the names of Earth's major plates. (Note that spreading rates are typically double the velocities of the two plates moving away from a ridge.). The addition of water to the hot mantle lowers the rockss melting point and leads to the formation of magma (flux melting) (Figure \(\PageIndex{6}\)). The Cascadia Subduction Zone and Southern Alaska are the sites of ongoing subduction as the Pacific and Juan de Fuca plates slide beneath the North American Plate. This plate is moving north east towards the Eurasia plate and the Pacific plate. As a result of this collision, the oceanic Cocos plate is subducted below the Caribbean along the Mesoamerican trench plate at speeds ranging from 2 in. USGS photo. Error message | View complete answer on https://www.britannica.com Are the Nazca Plate and South American plates divergent plates? . The rising water melts rock in its path, forming a volcanic arc on the overrriding plate. As explained above, most transform faults connect segments of mid-ocean ridges and are thus ocean-ocean plate boundaries (Figure \(\PageIndex{11}\)). The Pacific Plate is the fastest, followed by the Australian and Nazca Plates. National Park Service sites in the Coastal Ranges of Washington, Oregon and northern California contain rugged mountains of rocks that were manufactured in the ocean, then scraped off the plate and lifted out of the sea. Download the official NPS app before your next visit, Accretionary WedgeCoast Ranges [3 parks], Accretionary WedgeSouthern Alaska [1park]. Some parks in the Sierra Nevada Mountains reveal igneous magma chamber rocks that represent the eroded remnants of an ancient subduction zone, when volcanoes similar to those found in the modern Cascade Mountains extended southward all the way through California. If this continues without changing for another couple hundred million years, we will be back to where we started, with one supercontinent. Is the Nazca Plate a convergent boundary? A divergent boundary occurs when two tectonic plates move away from each other. 40 Million Years Ago The line of active volcanoes, from Mt. Hydrothermal features on the flanks of Lassen Peak include numerous hot springs, mudpots and fumaroles that suggest there is still hot magma beneath the mountain. Point Reyes National Seashore and Golden Gate National Recreation Area are the only two NPS sites that are right on the San Andreas Fault.
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