1. Compare and contrast the structural features found in convergent and divergent ocean basins.
Beginning with the most obvious difference, divergent ocean basins are essentially two plates which are moving away from one another. Contrasting, convergent ocean basins are essentially two plates moving towards one another. For the second difference, I want to focus on what is happening to the Earth’s crust at each point. In divergent ocean basins, new crust is being formed as the two plates move father and farther away. In contrast, crust is being destroyed at converging ocean basins. Essentially, the two converging plates (and their crust) will collide and form a subduction zone (specific with the crust density). This zone is essentially characterized
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Submarine canyons can be found at active and passive margins, while deep sea trenches can only be found at active margins. The primary reason for this difference is specific to how submarine canyons and deep sea trenches are formed. If we think back to what occurs at active and passive margins, it becomes apparent that deep sea trenches are only formed from some form of a tectonic collision. Submarine canyons, presenting at passive and active margins, are largely formed by turbidity currents. The last difference between a submarine canyon and a deep sea trench is “placement”/shape. The most apparent location of a submarine canyon is on the down slope of a continental shelf; furthermore, as the slope continues downward the canyon essentially ends by formation of a deep sea fan. While I was supplementing the text, one perfect analogy for a deep sea fan (more of a visual aid) that I found online was those formed at the opening/mouth of a river. Essentially, as sediment continually flows over a specific path, the path begins to erode and you get fan like formations from the mouth. In contrast, deep sea trenches are more prominent and “sharp” in nature. Rather than running perpendicular to a continental slope, deep sea trenches are physical depression originating from the ocean floor and protruding downward in a “V” shaped
This lab uses earthquake data to construct profiles of two convergent boundaries: the Tonga Trench and the Peru-Chile Trench. Where two tectonic plates converge, if one or both of the plates is an oceanic lithosphere, a subduction zone will form. When crust is formed at a mid-ocean ridge, it is hot and buoyant meaning it has a low density. As it spreads away from the ridge and cools and contracts, or becomes denser, it is able to sink into the hotter underlying mantle. When two oceanic plates collide, the younger of the two plates, because it is less dense will ride over the edge of the older plate. The density of the
Pushing forces generated in the lithosphere above the adjacent downgoing portion of the convection cell result in the formation of a deep-sea trench that eventually develops into what type of plate
The theory of plate tectonics states that Earth’s outer shell is divided into plates. The crust and upper mantle is broken into plates that move around on the mantle, changing in size throughout time. The lithosphere makes up the crust and upper mantle and the asthenosphere a plastic like layer beneath the lithosphere. There are three types of plate boundaries. Divergent boundaries where two plates move away from each other. The ocean widens and new crust forms at the mid-oceanic ridge. Convergent boundaries has three types of converging, moving two plates towards each other. First we have an ocean floor plate that collides with a less dense continental plate. Next an ocean floor plate collides with another ocean floor plate. Finally a continental plate collides with another continental plate. Transform boundaries were two plates slide past one another. The resulting effects of plate tectonics is landforms such as rift valleys,
They have sinuous, curving channels and their heights are higher compared to their widths (Thompson & Thompson, 2003). Irregularities toward the local direction of slant cause paths sinuosity. Canyons located in the Mammoth Cave run up to 80 to 100 feet high and 10-30 feet wide but many of them are not that high and much narrower. Vertical shafts are created where water can run down vertically alongside fractures (Call, 2010) as illustrated in figure 6.
As mentioned before, water was a major agent in the creation of these caves. Geologists say that the formation of these caves can be traced back all the way to the Cambrian period which was about six hundred million years ago. Back in the time which is present day Nevada and western Utah, the land was covered by shallow, warm, inland sea. There were msny thick layers of sediments located at the sea bottom. Some of the layers consisted of silt, others were sand, and there were others that were made up of a limy substance that came from minute shell creatures’ decomposed bodies. In one of those limy layers was to formulate into limestone to create the Lehman Caves. That limy layer was compacted by the weight of other latter sediments deposited on top of it. Since there was so much pressure, eventually that limy layer started to turn into limestone. Limestone is a cystalline or bioclastic rock that is composed of calcite. Later on as there was an increase in heat and pressure, some of the limestone formulated into some low-grade marble. Marble is a nonfoliated, metamorphic that is composed of calcite and/or dolomite. Its texture is fine to coarse. According to “The Formation of Lehman Caves”, “Later, great forces under the earth’s crust caused the layers of the rock to buckle. This mountain range (the buckle) rose gradually until its peaks were thousands of feet above the valley
Pitch black, dead quiet and seemingly desolate, the deep sea resembles that of a far off alien world. Until recent advancements in technology, little to none has been known about the deep sea. Far beyond the natural reach of humans, only highly expensive submersibles have visited the ocean’s deepest and darkest locations. In the Pacific Northwest, an eerie 7-mile venture underwater will take you to the deepest spot on the planet, Challenger Deep in the Mariana Trench.
In the Western Pacific Ocean traveling to the Southern end of the Mariana Trench, a crescent shape canyon, lies the deepest part of the ocean called “Challenger Deep” reaching down to approximately 36,070 feet. Also down 20,000 feet to the deepest and darkest place in the Trench can be found the “Hadal Zone” named after the Greek God Hades, associating it to his underworld. As far as we know only about three people have traveled down to this part of the ocean such as Film Director James Cameron in 2012 and two scientist aboard the Trieste in 1960. In 1875, a British survey ship called “HMS Challenger” expedition was the first to actually discover these depths during a global circumnavigation, making the deepest point in the ocean named after
The three major types of tectonic plates are divergent, subduction and transform. Divergent plates tend to move apart from each other. Subduction plates are when oceanic plate moves under a continental plate. This can cause volcanos to erupt and large sized earthquakes. Transform plates slide back and forth against one another. The Lithosphere consists of the Earths crust and uppermost mantle. The North American plate and the South American plate are the major plates of the lithosphere. The lithosphere also consists of the Pacific plate, the African plate and the Eurasian plate. The Pacific plate is the only major plate that is mainly underwater and is also the largest plate in the lithosphere. The Earth was once one large continental body called Pangea, before the plates started
Explain to the class that another type of plate tectonics, when the plates crash into each other, is called convergent, and that this causes the Earths crust to be pushed into the interior where it is remelted at the same rate the new crust is being made. Discuss the two kinds of surface features associated with them, then describe to them that with oceanic convergence, a deep ocean trench is formed along a line of the
The breaking apart of this supercontinent was due to the movement of the Earth's Tectonic Plates. Tectonic Plates are large masses of the lithosphere or outer layer of the Earth's surface. The layers included in the Lithosphere are the Crust up to the upper layer of the Mantle. The Oceanic Crust is thinner and denser than the Continental Crust and can be found underneath the ocean. It is also more active than the Continental Crust that stretches 200 km below the Earth's surface. This crust drifts and moves either horizontally or vertically causing geological phenomenons such as earthquakes, volcanic eruptions, etc. The major tectonic plates are North American, Caribbean, South American, Scotia, Antarctic, Eurasian, Arabian, African, Indian, Philippine, Australian, Pacific, Juan de Fuca, Cocos, and Nazca. These plates move an estimate of 1 to 10 cm per year causing interaction at plate boundaries. When two plates are colliding or moving toward each other it is in Convergent boundaries. If these two plates are Oceanic Crusts, they are in Subduction zones wherein the denser plate in forced beneath the less dense plate and would eventually melt or destroy. On the other hand, when two plates move away from each other it is in Divergent boundaries. New crust material from molten magma formed below may fill the space between these plates or become ocean basins.
The seven major tectonic plates comprise mostly on continental plates and the Pacific plate. The seven major plates from greatest to least are called: the Pacific Plate stretching 103,300,000 km2, North American Plate being 75,900,000 km2, Eurasian Plate being 67,800,000 km2, African Plate stretching 61,300,000 km2, Antarctic Plate being 60,900,000 km2, Australian Plate being 47,000,000 km2, and the South American Plate being 43,600,000 km2. With different tectonic plates, there are different ways they can move: divergent, convergent, and transform. Divergent plate movement is when both plates moving away from each other, creating a canyon that has magma pushing out from the bottom, forming new ground. Convergent is usually an oceanic plate and a continental plate are moving into one another, causing the oceanic plate to subducts into the mantle. This causes move active volcanos and earthquakes. Even though all of the plates are in the lithosphere, it's only the where Earth is flexible enough to move rather than flow. The lithosphere flexes when loads of weight are placed on it or
The different tectonic plates rest on the mantle, a very hot layer of earth that is directly beneath the crust. There are seven major tectonic plates, their names are The Pacific Plate, The North American Plate, The Eurasian Plate, The African Plate, The Antarctic Plate, The Australian Plate, and The South American Plate. In addition to these major plates there are also many smaller tectonic plates that make up parts of the Earth's crust. When the boundaries between plates shift, this causes earthquakes. There are three types of movements that cause earthquakes. Divergent is when the plates move away from each other, Subduction is when one plate moves underneath another, and Transform is when the plates grind against each other. The lithosphere is another name for earth's crust and mantle, it is made up of all the tectonic
There are many differences between continental drift and sea-floor spreading and plate tectonics. there are also lots of differences between continental drift and sea-floor spreading and plate tectonics. They all have different factors that makes them different or the same. Sea-floor spreading is an important part of the world. Plate tectonics and continental drift are all also an important part of the world. There is a lot of ways to tell you about the differences and similar traits like showing you or just simply telling you about them.
There are three distinct types of plate boundaries existing, which are supported by geological observation, geophysical data, and theoretical considerations. Their names and categories are based on if adjacent plates move apart from each other (divergent plate margins), toward one another (convergent plate margins), or slip past one another in a direction parallel to their common boundary (transform plate margins) (Pitman, W.C., 2007).
Each plate is moving a certain direction due to the convection from the Asthenosphere. The meeting of two plates is called a boundary, there are three types of boundaries in the world: Convergent Boundaries, Divergent Boundaries. And Transform Boundaries. In the case of Convergent Boundaries, two plates are pushing against each other, which can create Deep Ocean Trenches, Huge Mountains, and/or Volcanic Mountain chains. An example of this happening is the Mariana Trench, During Convergence, the denser crust, oceanic crust, is subducted below the less dense crust. If the crusts have the same density then the plates are pushed upwards. At Divergent Boundaries, the plates are moving away from each other, this can create Mid-Ocean Ridges and Rift Valleys. An example of this happening is the Mid-Atlantic Ridge. At the final boundary, Transform Boundaries, the plates slide the past one another in the opposite direction, causing shallow earthquakes and offset features. An example of this Boundary is The San Andreas Fault. While the crust moves, there are places called Hot spots in which a hot portion of the mantle rises up beneath the crust for millions of years. An example of this is the Hawaii Island