oceanic crust and continental crust

The oceanic crust is younger than the continental crust of 3.8 billion years old. Continental crust is thicker and generally older (think about Pangaea. The continental crust can be between six and forty-seven miles thick. Seismic studies reveal that the oceanic crust is not deformed into folded mountain structures. Some of the magma rises still higher to fill vertical cracks, where it solidifies and forms wall-like sheets, or dikes of basalt. Since oceanic crust is heavier than continental crust, it is constantly sinking and moving under continental crust. Due to this difference in densities in magma between the oceanic crust and the continental crust, … Comparison Between Oceanic Crust And Continental Crust. One is called the Oceanic Crust, and the other, the Continental Crust. Continental crust is the outermost layer of lithosphere on the land. The region of a continent that has been structurally stable for a prolonged period of time is called a craton. The properties like density, buoyancy, age and heal flow value of the continental crust (though vary with vertically) remain constant laterally which play a prominent role in plate tectonics. This process, called subduction, occurs at the oceanic trenches. Explanation: Oceanic crust is the outermost layer of earth's lithosphere under the ocean. Of course, it beats the previous record of … Required fields are marked *. External energy sources manifest themselves in subaerial weathering, erosion, transportation and deposition by geomorphic agents like wind, ocean, river and ice. As with oceanic crust, continental crust is created by plate tectonics. Tonalite-trondhjemite-granodiorite rocks or TTG, along with the granite magma generated from the partial melting of TTG or by fractional crystallization, is the major source of formation of continental crust. As … The oceanic crust is denser than the continental crust. Continental Crust The continental crust accounts for 40% of the surface of the Earth. Firstly, there is the difference of pressure applied to the … Despite their greater density, oceanic plates average only about four or five miles in thickness, compared to an average of 25 miles for continental plates; under major mountain belts, the continental crust can reach nearly 50 miles thick. However, hydrothermal alteration of ocean floor produces some altered rocks like serpentine and spilite. So it is less dense than the oceanic crust. Continental Crust. Oceanic crust is thin; the depth to the Moho averages 5 – 7 km. A feature unique to oceanic crust is that there are areas known as mid-ocean ridges where oceanic crust is still being created. According to isostasy, the rocks composed of lighter materials are more buoyant than denser rocks, hence possess higher elevation. How is oceanic crust different from continental crust? This evidence asserts about the existence of oceanic crust prior to formation of continental crust. The lavas are generally of two types: pillow lavas and sheet flows. The continental crust consists of a wide range of metamorphic rocks such as gneiss, schist, slate, marble and metamorphic rocks compositionally similar to granite. Crustal accretion in the oceanic realm is lateral and the layers accumulate side by side because dikes intrude into dikes as they are injected from the magma chamber below. The continental crust is highly affected by deformation and metamorphism. Shield, Craton, Platform, Continental shelf, Continental slope, basin, folded mountain belt etc. As the two plates pull apart, normal faults develop on both sides of the rift, and the central blocks slide downwards. That means it is apparently not subjected to strong compressional forces. Continental crust is made up of many different rocks (Figure below).All three major rock types—igneous, metamorphic, and sedimentary—are found in the crust. Continental crust is the crust under which the continents are built and is 10-70 km thick, while oceanic crust is the crust under the oceans, and is only 5-7 km thick. When oceanic crust and continental crust collide, _____ always subducts. The crust is the top layer of the Earth’s Surface. Continental Crust (Sial) Old, light, thick (up to 150km under mountains) permanent, does not sink. Continental crust also consists of the shallow seabed close to shores called continental shelves. The oceanic crust is presumed to be formed around 4.5 billion years ago, before the formation of continental crust. Less dense layers float on top of denser ones such as the mantle. The continental crust thins seaward from a thickness of about 30 km beneath the coastal plain to about 10 km beneath the continental slope off Cape Hatteras (Fig. The upper continental crust being granitic to granodioritc in composition is enriched in radioactive elements like U, Th and K. The greater thickness and lower density of continental crust make it more buoyant than oceanic crust. So the oceanic crust becomes denser and cooler as it moves away from mid oceanic ridge. In divergent plate boundaries, the lithospheric plate gets faulted, fractured and distinctly separate with the widening and deepening of the rift valley. Continental slope is considered to be the boundary or transition between basaltic oceanic crust and granitoid continental crust. It infers the continental crust is likely to be formed around 4.36Ga. In general, continental crust is far older than oceanic crust. Magma additions by crustal underplating: Magma from the mantle may be added to the crust by underplating, involving the intrusion of sills and plutons. The oceanic crust is thinner while the continental crust is much thicker. By contrast, the continental crust is made up of light-colored granite rocks full of substances like oxygen and silicon. The continental crust remains unchanged from the time of formation. The continental rocks are mainly granite rocks. The continental crust has both positive and negative relief. Because of basaltic composition, radioactive elements are absent in oceanic crust. The continental crust is the repository of all geological processes occurring since Archean era where as present oceanic crust can deliver any information regarding geological activities up to Jurassic age. About 40% of Earth's surface area and about 70% of the volume of the Earth's crust is continental crust. Continental crust is also less dense than oceanic crust, though it is considerably thicker; mostly 35 to 40 km versus the average oceanic thickness of around 7-10 km. Continental crust is made of granite. Hence recreation or regeneration or destruction processes are not observed in continental crust. Oceanic crust has more heat flow value than the continental crust. Also Know, what causes the difference in temperature between the 2 types of crust? In this way, the entire ocean floor is completely regenerated in 200 or 300 million years. Characteristics of the crustThere are 2 main types of crust that lie on plates and each has its own characteristics: Oceanic Crust (Sima) Young (under 200 million years), thin, dense and heavy, will sink. The  continental crust has a great variety of topography because of myriad geological activities occurring due to internal and external energy sources. Crustal deformation leads to oogenesis and basin formation over the long term. The transition from oceanic to continental crust occurs in a distance of about 100-20 Difference Between Oceanic and Continental Crust The oceanic crust is mainly made out of dark basalt rocks that are rich in minerals and substances like silicon and magnesium. This rock is made up of silicon, oxygen, and magnesium. Continental crust is the surface that forms land masses, and oceanic crust is the surface found under the ocean floor. What is the theory of continental drift? lithosphere contains only the oceanic and continental crust 2. asthenosphere overlies the lithosphere 3. asthenosphere contains the oceanic crust and mantle 4. lithosphere contains the crust and the upper part of the mantle 14. Continental crust tends to be much older than the oceanic kind, and rocks found on this kind of crust are often the oldest in the world. The crust is subdivided into two types, oceanic and continental. Maximum heat flow value is observed at mid oceanic ridge axis reaching its lowest value at subduction zone. Oceanic Crust The oceanic crust is that part of the Earth’s crust that covers the ocean basins. the older one The continental crust is of variable thickness with an average thickness 35-40 km. Continents do something different from oceanic crust. Oceanic crust is the uppermost layer of the oceanic portion of a tectonic plate.It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumulates. Will be preferentially subducted is not deformed into folded mountain structures has somehow ferromagnesian minerals mid-oceanic ridge is solid. Of formation true oceanic crust axis, the dense oceanic lithosphere subducts beneath the continental crust 3.0... Some of the mantle.The crust and mantle layers are mostly rocks and minerals while the center is hot! 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