Question about Earth?

Question

What is oceanic crust, continental crust, Moho, lithosphere, asthenosphere, plasticity, mesosphere and outer core?

Answer 1

Oceanic crust is the part of Earth's lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima. It is thinner than continental crust, or sial, generally less than 10 kilometers thick, however it is more dense, having a mean density of about 3.3 grams per cubic centimeter.

The outer core of the Earth is a liquid layer above the solid inner core. It is located from 2,890 to 5,150 km (1,800 to 3,200 mi) below the Earth's surface.

The continental crust is the layer of granitic, sedimentary, and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called sial due to its granitic rock, in contrast to the oceanic crust, called sima due to its basaltic (also called mafic) rock. Due to the change in velocity of seismic waves it is believed that on continents at a certain depth sial becomes close in its physical properties to sima and the dividing line is called Conrad discontinuity. Consisting mostly of granitic rock, it has a density of about 2.7g/cm3 and is less dense than the material of the Earth's mantle, which consists of mafic rock. 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. About 40% of the Earth's surface is now underlain by continental crust.

The Mohorovičić discontinuity, the boundary between the Earth's crust and the mantle.

The town of Moho, Peru in the Puno Region of Peru

The Moho Province in the Puno Region of Peru

The lithosphere (IPA: [ˈlɪθ.ə.sfiɹ], from the Greek λίθος [líthos] for "rocky" + σφαίρα [sfaíra] for "sphere") is the solid outermost shell of a rocky planet.

earth's lithosphere

On the Earth, the lithosphere includes the crust and the uppermost mantle which is joined to the crust across the Mohorovičić discontinuity. The lithosphere is underlain by the asthenosphere, the weaker, hotter, and deeper part of the upper mantle. The boundary between the lithosphere and the underlying asthenosphere is defined by a difference in response to stress: the lithosphere remains rigid for long periods of geologic time, whereas the asthenosphere flows much more readily. As the conductively cooling surface layer of the Earth's convection system, the lithosphere thickens over time. It is fragmented into tectonic plates (shown in the picture), which move independently relative to one another. This movement of lithospheric plates is described as plate tectonics. This is when plates move horizontally across the Earth's surface and the continents change their relative positions.

The concept of the lithosphere as Earth’s strong outer layer was developed by Barrell, who wrote a series of papers introducing the concept (Barrell 1914a-c). The concept was based on the presence of significant gravity anomalies over continental crust, from which he inferred that there must exist a strong upper layer (which he called the lithosphere) above a weaker layer which could flow (which he called the asthenosphere). These ideas were enlarged by Daly (1940), and have been broadly accepted by geologists and geophysicists. Although these ideas about lithosphere and asthenosphere were developed long before plate tectonic theory was articulated in the 1960s, the concepts that strong lithosphere exists and that this rests on weak asthenosphere are essential to that theory.

The division of Earth's outer layers into lithosphere and asthenosphere should not be confused with the chemical subdivision of the outer Earth into mantle, and crust. All crust is in the lithosphere, but lithosphere generally contains more mantle than crust.

There are two types of lithosphere:

Oceanic lithosphere, which is associated with Oceanic crust

Continental lithosphere, which is associated with Continental crust

The asthenosphere (from an invented Greek ἀσθενός a + ''sthenos "without strength" and Greek word σφαίρα (sphera) meaning globe) is the region of the Earth between 100 and 200 km (~ 62 and 124 miles) below the surface — but perhaps extending as deep as 400 km (~ 249 miles) — that is the weak or "soft" zone in the upper mantle.

Plasticity generally means ability to permanently change or deform. (It differs from "elasticity", which refers to ability to change temporarily and revert back to original form.)

Plasticity (physics): In physics and engineering, plasticity is the propensity of a material to undergo permanent deformation under load. In civil engineering, plasticity of a soil is quantitatively determined by Atterberg Limits testing

Plasticity (psychology): An intelligence factor that determines the ease of changing ones perception of a situation for finding a new solution to a problem. Lack of plasticity is termed rigidity.

The mesosphere (from the Greek words mesos = middle and sphaira = ball) is the layer of the Earth's atmosphere that is directly above the stratosphere and directly below the thermosphere. The mesosphere is located from about 50 km to 80-90 km altitude above Earth's surface

Within this layer, temperature decreases with increasing altitude.[1] The main dynamical features in this region are atmospheric tides, internal atmospheric gravity waves (usually just called "gravity waves") and planetary waves. Most of these waves and tides are excited in the troposphere and lower stratosphere and propagate upward to the mesosphere. In the mesosphere, gravity-wave amplitudes can become so large that the waves become unstable and dissipate. This dissipation deposits momentum into the mesosphere and largely drives its global circulation.

Answer 2

Hooee - sound suspiciously like homework.

Wikipedia 'structure of the earth' is excellent and easy to understand.

Answer 3

www.

read your schoolbock

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