6. The west coasts of the Americas, with relatively narrow continental margins similar to the left profile in Figure 1, are tectonically [(active)(passive)]. Figure 2 displays a section of the South American west coast as an example, with a dark-blue ocean trench in close alignment to the green coastal land areas.…
At a hotspot, the underlying mantle is hotter than average causing ‘mantle plumes’ to rise to the bottom of the lithosphere, find a thin or weak part of the lithosphere, and breaks through. In the case of the Hawaiian islands, the hotspot is underneath an oceanic plate and the lava has built up until it is higher than the surface of the sea. These hotspots remain in the same place in relation to the mantle, but the plates move across the hotspots. The Pacific plate has moved across a hotspot in the ocean leaving the chain of Hawaiian Islands which have been formed at different times over millions of years. By dating the rocks which make up the Hawaiian Islands, it is clear that the tectonic plate must be moving in relation to the hotspot- a key piece of volcanic evidence.…
Tectonic plate’s movement creates ocean basins, mid-ocean ridges, through collision. Colliding plates push sedimentary materials into an uplifted mass of rock that contains numerous folds and faults. The Earth has undergone a number of mountain building periods. The process of creation is first by the accumulation of sediments then the tectonic collision causes rock deformation and crystal uplift and finally the isocratic rebound continues to cause uplift despite erosion and causes the development of new mountain peaks through block faulting.…
The earth’s crust is made out of plate tectonics. Each plate has a defined boundary and direction it moves. The plates in Earth’s crust perform two actions; they submerge under each other or they spread out. The Pacific Plate is the largest plate and it borders around many plates. The Pacific Plate moves northwest. New crust is formed from magma outpours, which are a result of the zones spreading. The tectonic plates created the islands. When the tectonic plates move, it creates the change in geography. Active volcanoes together shape the way islands are build. The magma from the volcano and the deposits from the plate are needed to create the pacific islands structure. The buildup of deposits eventually pushes pass sea level to create the island. The islands that are part of the same volcanic chain will all take over a millions years to rise.…
Effect of earths rotation tends to deflect air/water toward right in Northern hemisphere and left in Southern hemisphere…
4. What kind of plate boundary exists between the Juan de Fuca and the North American plate?…
The reason for this is because of the buckling and stress from the movement of the tectonic plates. The epicenter of the earthquake was 60 meters below the ocean floor about 100 miles off the coast of Chile. Valdivia and Puerto Montt suffered significant damages based on how nearby they were to the center of a massive quake (extreme). The earthquake was a megathrust earthquake which is caused by the release of mechanical stress between the subducting Nazca Plate and the South American Plate which is on the Peru-Chile…
The global seismic and volcanic activity is concentrated along the margins of the earth’s plates, which are broken pieces of the crust and are moved by convection currents that are caused by heat rising and falling inside the mantle generated by radioactive decay in the core. This movement of the plates and the Earth’s inner activity is called plate tectonics and can cause seismic and volcanic activity. However, earthquakes and volcanoes also occur within the plates rather than their edges, an example of which is the Hawaiian volcanoes that occur above a stationary hot spot beneath the Pacific plate. In the late 1960s the theory of plate tectonics was developed by Alfred Wegener and provides an explanation for the Earths tectonic behaviour, particularly the global distribution of mountain building, earthquake activity, and volcanism in a series of linear belts. However, before the theory was developed people had noticed that the continents either side of the Atlantic Ocean seemed to nearly fit together. In 1912 Alfred Wegner published the theory of continental drift suggesting that the continents used to be joined together in an ancient supercontinent which he named Pangaea. He then proposed that it later split in to two continents- Laurasia in the north and Gondwanaland in the south, which further split forming our current continents and at some point these land masses had drifted apart to their current positions on the globe.…
The youngest crust occurs near the west coastline of North America near the North American and Juan de Fuca Plates. The oldest crust is along the Japan Trench and Marianas Trench. This is the outermost layer of the Earth.…
plate. This can be proved because magma comes out from the fault of ridge which means plate…
Gabbro and basalt are both formed from the cooling of magma – but they differentiate because of different rates of cooling. Last week we had a quick introduction to plate tectonics and diverging oceanic plate boundaries where magma rises – this image represents the composition of those regions.…
This specific plate has brought up ocean floor, and pieces of continents northward to form accretionary terranes. Most of this terrane are known as groups of rocks that are surrounded by faults, different types of fossils, and other types of physical properties. Due to the Pacific Plate subducting beneath the North American plate, it creates the Denali fault system. Denali consists of a right lateral strike-slip fault over 720 miles long (Sharpe). This strike-slip fault is a part of the larger fault system which includes the San Andreas Fault system in…
the Earth; plate tectonics and the structure of the Earth's crust; minerals and igneous, sedimentary…
With continued subduction and convergence, volcanic islands collided with North America and those rocks were thrust up on the continental margin. Deformation, metamorphism and magmatism accompanied this collision and gave rise to the Taconic Orogeny. Rocks metamorphosed and deformed in this event are seen in the Blue Ridge and Piedmont provinces. This…
With the advent of plate tectonics, it was discovered that new oceanic lithosphere is being created at what location?…