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 Cocos Ridge (CR), which formed when the Cocos Plate drifted over the Galapagos Hotspot (Walther, 2003) , is a bathymetric high reaching about 2 km above the surrounding seafloor and stretching about 2000 km long and 200-300 km wide across the Cocos Plate . 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. This subduction forms the volcanoes of Guatemala, El Salvador, Nicaragua, and Costa Rica, also known as the Central America Volcanic Arc. It is assumed that the relative lack of strength of the partial melting zone facilitates the sliding of the lithospheric plates. Wrangell (left) and Mt. By 80 Ma, Africa had separated from South America, most of Europe had separated from North America, and India had separated from Antarctica. Redoubt, on the eastern side of the park, had four explosive eruptions that resulted in large volumes of ash and mudflows. This plate moves north and slightly west towards the Caribbean plate and the North America plate. The original composite volcano was about 7,000 feet (2,000 meters) high, but lost about 2,500 feet (750 meters) of its height. The Pacific Plate is the fastest, followed by the Australian and Nazca Plates. Cocos Tectonic Plate | LAC Geo 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. Increased temperature and pressure at that depth cause the rocks to metamorphose and dehydrate (sweat). A visit to Olympic National Park is an opportunity to witness features of an accretionary wedge as they develop. Yosemite National Park, California New Guinea and the northern parts of New Zealand are part of the Australia plate. Transform faults do not just connect divergent boundaries. Download the official NPS app before your next visit, Accretionary WedgeCoast Ranges [3 parks], Accretionary WedgeSouthern Alaska [1park]. As originally described by Wegener in 1915, the present continents were once all part of a supercontinent, which he termed Pangea (meaning all land). The Cascade Volcanoes extend in a north-south line from Mt. Transform boundaries exist where one plate slides past another without production or destruction of crustal material. The Cocos Plate is a small, oceanic plate just to the west of Central America. Most of the igneous rocks were manufactured in the ocean and are basalt. Farther east, the continent began to rift apart in the Basin and Range Province. Crater Lake National Park has the 9th deepest lake in the world. Storms coming in from the Pacific Ocean drop most of their moisture on the Coast Range and Cascades, leaving eastern Oregon and Washington high and dry. Magma from the mantle pushing up to fill the voids left by divergence of the two plates, Magma cooling more slowly in the lower part of the new crust and forming gabbro bodies, Figure \(\PageIndex{1}\): Plates tect2 en by the. Plate Boundaries Divergent UU) Transform North American Plate Convergent Other Plate Motion Caribbean Plate Indias Plate motion vectors rotated based on the direction of plate movement Cocos Plate Pacific Plate South American Plate Google Earth Z age Landsat / Copernicus ata SIO, NOAA . Would you characterize earthquake activity as. The Cocos plate is found on the west side of Mexico. This plate includes the northeastern part of the Atlantic ocean, all of Europe, all of Russia (except its most eastern part), and down through southeast Asia, including China and Indonesia. Plate tectonics is the theory that the crust of the earth is broken up into giant slabs of rocks that sort of fit together like puzzle pieces. rare Examine the interactive globe. But thousands of eruptions over less than a million years have built Mount Rainier and other Cascade peaks to elevations of more than 10,000 feet (3,000 meters)! Visits to coastal NPS sites in the Pacific Northwest can help us appreciate the landscapes that develop over time because of these large quakes, and learn how we are preparing our homes, communities, and infrastructure for the next Big One.. A mid-oceanic ridge, a divergent tectonic plate boundary located along the floor of the Pacific Ocean. Caribbean Plate | Geology Page 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. It is released when the oceanic crust is heats and then rises and mixes with the overlying mantle. This plate is moving northwest towards the Australia, Filipino, and Eurasia plates. Photo courtesy of Robert J. Lillie. Subduction of the Cocos plate beneath the North American plate along the Middle American Trench in Mexico generates large to great earthquakes every 30-100 years. This plate is moving north north east towards the Eurasia plate. Based on Keary and Vine, 1996, Global Tectonics (2ed), Blackwell Science Ltd., Oxford. This subduction-subduction-transform (SST) triple junction is referred to hereafter as the NACC triple junction. National Park Service Sites in the Southern Alaska Subduction Zone reveal a variety of active volcanic features above the zone where the top of the Pacific Plate reaches sufficient depth where temperature and pressure are high enough to dehydrate rocks and form magma. In 1989 and 1990, Mt. Yosemite Valley and Half Dome. Introduction The Cocos Plate is a relatively small sized, triangular-shaped oceanic plate located just west of Mexico and the Caribbean. The Cocos Plate in the Pacific Ocean is subducted beneath the Caribbean Plate, just off the western coast of Central America. Mazama 7,700 years before, the material expelled from its magma chamber did not spew forth out of the top of the volcano. Crater Lake partially fills the caldera of a volcano that erupted and collapsed in on Itself 7,700 years ago. 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. Redwood National and State Parks, California Images above modified from Oregon's Island in the Sky: Geology Road Guide to Marys Peak, by Robert J. Lillie, Wells Creek Publishers, 75 pp., 2017, www.amazon.com/dp/1540611965. The Caribbean Plate is a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea off the northern coast of South America . The boundary between the two plates is the Nootka Fault, which is the location of frequent small-to-medium earthquakes (roughly up to magnitude 5), as depicted by the red stars. 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. A glance at a map of the western United States might suggest that the Sierra Nevada are a southward continuation of the Cascade Volcanoes. 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. This plate is moving directly east towards the South America plate. This plate is small. The line of active volcanoes, from Mt. This plate is bound by the North-American and Caribbean Plates to the north-east, the small Rivera Plate to the north-west, the Pacific Plate to the west, Left image When the plates suddenly let go, a massive earthquake will shake the entire Pacific Northwest, a series of tsunami waves will pound the Coast, and landslides will make it difficult to reach some of those in need. The volcano is still active, having erupted in 1931. On the western edge of the plate is a continuous subduction zone where the Cocos, Panama, and North Andean Plates are all converging with the Caribbean Plate. Kenai Fjords National Park 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. Boundaries between the plates are of three types: divergent (i.e., moving apart), convergent (i.e., moving together), and transform (moving side by side). Convergent Plate BoundariesSubduction Zones - National Park Service 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. Over time, the San Andreas boundary has grown longer as the Farallon Plate split into two separate platesthe Juan de Fuca Plate on the north, and the Cocos Plate on the south. Off the Pacific coast, the Cocos plate is subducted beneath both the North American and Caribbean plates, which are separated by a sinistral transcurrent boundary. A forearc basin develops in the low area between the two mountain ranges. The park is a complex amalgamation of blocks of continental and oceanic crust that have slammed into North America. Mount Rainier is a 14,000 foot (4,300 meter) volcano in the Cascade Range developed above the place where the subducting Juan de Fuca Plate reaches sufficient depth to release hot fluids into the overriding North American Plate. Fortunately, no one was injured. The Cocos Plate was created approximately 23 million years ago when the Farallon Plate broke into two pieces, which also created the Nazca Plate. Transform boundaries where plates slide passed each other. Mount Rainier is a 14,000 foot (4,300 meter) volcano in the Cascade Range developed above the place where the subducting Juan de Fuca Plate reaches sufficient depth to release hot fluids into the overriding North American Plate. The low region between the two parallel mountain ranges is the, 150 miles inland, the top of the subducting plate reaches depths where its hot enough to generate fluids, forming volcanoes in the. St. Helens. North American Tectonic Plates | Facts, Movement & Locations - Video Legal. Multiple complex plate boundaries contribute lots of earthquake and volcanic activity in the region. Spreading rates vary considerably, from 2 cm/y to 6 cm/y in the Atlantic, to between 12 cm/y and 20 cm/y in the Pacific. Many National Park Service sites are found in active and ancient 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. Three others, Aniakchak National Monument, Katmai National Park, and Lake Clark National Park, are farther inland, along the active volcanic arc. Transform boundaries are places where plates slide sideways past each other. Sea lions resting on layers of pillow basalt that formed beneath the ocean and were uplifted as part of the accretionary wedge. Farther east the Juan de Fuca Plate descends deeper and deeper. North America plate, Australia plate, Antarctic plate, Nazca plate, Filipino plate, Cocos plate, Juan de Fuca plate. It runs from the tip of South America eastwards to form a barrier between the Antarctic plate and the South America plate. The southern boundary is a mid-oceanic ridge, the Galapagos Rise. And, as at Mt. The east coast of North America is a passive margin and not a plate boundary. This can be demonstrated by stacking the three quarters with California on the bottom, overlain by Oregon and then Washington. A mature island arc develops into a chain of relatively large islands (such as Japan or Indonesia) as more and more volcanic material is extruded and sedimentary rocks accumulate around the islands.
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