In what general direction is the Pacific Plate moving? The plates are made up of crust and the lithospheric part of the mantle (Figure \(\PageIndex{2}\)), and even though they are moving all the time, and in different directions, there is never a significant amount of space between them.
There are two kinds of plates oceanic and continental plates.
Transform boundaries exist where one plate slides past another without production or destruction of crustal material. And I want to make clear, this movement is relatively slow.
National Park Service sites along the transform plate boundary in California contain rocks formed during the earlier subduction that occurred in western North America. North America plate, South America plate, Cocos plate. Notice what happens as you move your left hand away and slide your right hand toward you.
This is a map of the main tectonic plates that comprise the Earth's surface: In the Pacific Northwest, movement of three tectonic plates drive our earthquake hazard.
Like many of the rocks that are caught up in the zone of transform motion between the Pacific and North American plates, the rocks at Channel Islands National Park were deformed as part of the accretionary wedge during earlier subduction of the Farallon Plate. The Pacific Plate originated at the triple junction of the three main oceanic plates of Panthalassa, the Farallon, Phoenix, and Izanagi Plates, around 190 million years ago. WebThis chain has formed as the Pacific Plate moved northwest over a hot spot (Steven Earle, Physical Geology).
This subduction zone landscape was later plucked from the edge of the North American Plate and transported nearly 200 miles northwestward along the San Andreas Fault.
On the east, the North American Plate is subducting westward, forming volcanoes of the Lesser Antilles Island Arc. 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. Parks in western California contain blocks of crust that have moved great distances north-northwestward along the San Andreas Fault. Its motion is not smooth, but rather sticky; strain builds up until the fault breaks and a few meters of Juan De Fuca slips under North America in a big Megathrust earthquake. As originally described by Wegener in 1915, the present continents were once all part of a supercontinent, which he termed Pangea (meaning all land).
Feature labels. The North American Plate, for example, rotates counter-clockwise; the Eurasian Plate rotates clockwise. The grinding action between the plates at a transform plate boundary results in shallow earthquakes, large lateral displacement of rock, and a broad zone of crustal deformation.
Based on Keary and Vine, 1996, Global Tectonics (2ed), Blackwell Science Ltd., Oxford.
These cookies will be stored in your browser only with your consent. Pillow basalt, formed as lava poured out on the ocean floor, was later scraped off the top of the subducting plate and thrust onto the edge of the continent. The plate forms a convergent boundary by subducting under the Philippine Sea Plate creating the Mariana Trench, has a transform boundary with the Caroline Plate, and has a collision boundary with the North Bismarck Plate.
The oldest part disappearing by way of the plate tectonics cycle is early-Cretaceous (145 to 137 million years ago). It includes many lesser faults in addition to the San Andreas Fault. WebAs the Pacific Plate continues to move west-northwest, the Island of Hawaii will be carried beyond the hotspot by plate motion, setting the stage for the formation of a new volcanic island in its place. The plate formed because the triple junction had converted to an unstable form surrounded on all sides by transform faults, due to the development of a kink in one of the plate boundaries. The locked zone varies in width from a few tens of kilometers (km) along the Oregon coast to perhaps a hundred km or more off of Washington's Olympic Peninsula, and is about 1,000 km long. The earthquake ruptured a large portion of the San Andreas Fault, including land that is now Point Reyes National Seashore and Golden Gate National Recreation Area.
Thisblock of crust is rotated west and pushed north into Washington state.
This feature includes the famous San Andreas Fault, responsible not only for destructive earthquakes, but also for the spectacular scenery of the San Francisco Bay area and other coastal regions of California. It caused extensive damage to the city, including fires that lasted for several days, and killed an estimated 3,000 people. 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.
The northern side is a convergent boundary subducting under the North American Plate forming the Aleutian Trench and the corresponding Aleutian Islands. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website.
Here, the Pacific Plate is moving northwest with respect to the North American Plate.
Point Reyes National Seashore and Golden Gate National Recreation Area are the only two NPS sites that are right on the San Andreas Fault. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org.
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 \(\PageIndex{10}\)).
The Cascades are the modern volcanic arc developing where the Juan de Fuca Plate subducts beneath the North American Plate. Shouldnt the line reading While the North American plate in the east moves in the southwest direction read southEAST direction? The broad zone of transform motion between the Pacific and North American plates formed numerous slivers of mountain ranges with narrow valleys in between. The Pacific Plate is being moved north west due to sea floor spreading from the East Pacific Rise (divergent margin) in the Gulf of California.
This map of gravity residuals measured over the puget lowland reveals a pattern of deep, fault bounded basins (cool colors) and uplifts (warm colors).
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. Photo courtesy of Robert J. Lillie. British Columbia, however, is part of rigid North America and moves with it. 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.
Filipino plate: This plate includes the islands that make up the Philipines and north to include parts of southern Japan. Beyond merely describing current plate motions, Plate Tectonics provides an overarching framework that connects many elements of Earth science. At an ocean-ocean convergent boundary, one of the plates (oceanic crust and lithospheric mantle) is pushed, or subducted, under the other. Boundaries between the plates are of three types: divergent (i.e., moving apart), convergent (i.e., moving together), and transform (moving side by side).
The islands contain sedimentary layers and pillow lavas that formed on the ocean floor. In California, much of the strain generated by the grinding of the Pacific Plate against North America is taken up in earthquakes on the San Andreas Fault and related structures, but the shearing action doesn'tend there. Are the Pacific Plate and the Antarctic Plate moving toward each other, away from each other, or past each other? a. Northwest because of the formation of newer islands (g) Assuming that the current direction of motion continues, what will be the eventual fate of the Meiji seamount? But opting out of some of these cookies may affect your browsing experience. Photo by Robert J. Lillie. It has higher density materials than the inner core. This plate makes up all of Antarctica and much of the surrounding ocean. Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. Proterozoic Eon: Eukaryotes to Multicellular Life (2500 to 541 million years ago), Indo-Australian Plate: Tectonic Boundaries and Movement, Soil Nutrients Deficiency and Replenishing, Pacific Ring of Fire: Volcanoes, Earthquakes and Plate Tectonics. Download the official NPS app before your next visit.
The sedimentary and metamorphic rocks across the fault line are similar to those found in Redwood National and State Parks on the North Coast of California.
Modern plate boundaries may be far different from ancient ones presumably marked by old fold belts.
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. This plate includes all of Saudi Arabia, and much of the Levant (up to Iraq and Syria).
The Pacific Plate is almost entirely oceanic, but it does include the part of California west of the San Andreas Fault. while the North America is being pushed to the southwest due to the spreading of the seafloor in the mid-Atlantic ridge. The South Whidbey Island Fault and Darrington Devil's Mountain Fault bound the Everett Basin. The valleys are commonly due to erosion along individual fault lines. WebThe Pacific Plate is moving to the northwest at a speed of between 7 and 11 centimeters (cm) or ~3-4 inches a year. Layers of ocean sediment were squeezed and contorted as they were caught in the vise of the converging plates at the ancient subduction zone. Already mentioned, the Pacific Ring of Fire has the most active chains of volcanoes in the world. about 43 million years ago The Pacific plate is moving at a rate of speed of 8.10 cm per year.
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Modified from Earth: Portrait of a Planet, by S. Marshak, 2001, W. W. Norton & Comp., New York.
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