Seismic Waves. One ingenious way scientists learn about Earth’s interior is by looking at how energy travels from the point of an earthquake. Seismic waves move faster through denser or more rigid material. As P-waves encounter the liquid outer core, which is less rigid than the mantle, they slow down.

The mantle lies between Earth’s dense, super-heated core and its thin outer layer, the crust. As Earth began to take shape about 4.5 billion years ago, iron and nickel quickly separated from other rocks and minerals to form the core of the new planet. The molten material that surrounded the core was the early mantle.

There are no samples of Earth’s core accessible for direct measurement, as there are for Earth’s mantle. Information about Earth’s core mostly comes from analysis of seismic waves and Earth’s magnetic field. The inner core is believed to be composed of an iron–nickel alloy with some other elements.

Core, mantle, and crust are divisions based on composition. The crust makes up less than 1 percent of Earth by mass, consisting of oceanic crust and continental crust is often more felsic rock. The mantle is hot and represents about 68 percent of Earth’s mass. Finally, the core is mostly iron metal.

Earth can be divided into three main layers: the core, the mantle and the crust. Each of these layers can be further divided into two parts: the inner and outer core, the upper and lower mantle and the continental and oceanic crust. The inner core is solid, while the outer core is liquid.

​​The earth is made up of three different layers: the crust, the mantle and the core. This is the outside layer of the earth and is made of solid rock, mostly basalt and granite. There are two types of crust; oceanic and continental. Oceanic crust is denser and thinner and mainly com​posed of basalt.

The flow of matter by convection in the solid mantle and the sinking of cold, dense crust back into the mantle exert forces on crustal plates that then move, producing tectonic activity. The addition of a significant amount of thermal energy released by radioactive decay in Earth’s crust and mantle.

Continental crust is typically 40 km (25 miles) thick, while oceanic crust is much thinner, averaging about 6 km (4 miles) in thickness. The less-dense continental crust has greater buoyancy, causing it to float much higher in the mantle.

Oceanic crust is made of basalt, dark in color, thin compared to continental crust (5 km thick vs 20-50 km), denser than continental crust, and geologically young. Continental crust is composed of granite, light in color, and thicker, less dense, and older than oceanic crust.

Layers that are less dense, such as the crust, float on layers that are denser, such as the mantle. Both oceanic crust and continental crust are less dense than the mantle, but oceanic crust is denser than continental crust. This is partly why the continents are at a higher elevation than the ocean floor.

Continental crust is low in density whereas oceanic crust has a higher density. continental crust is thicker, on the contrary, the oceanic crust is thinner. Continental crust floats on magma freely but oceanic crust floats on magma scarcely. Continental crust cannot recycle whereas oceanic crust can recycle it.

The oceanic crust, on the basis of seismological studies of the seafloor, dredge hauls, drilling, and studies of ophiolites on land, is layered consisting of an upper sedimentary layer, a middle basaltic volcanic layer, and a lower third layer consisting of gabbroic plutonic rocks.

Oceanic plates are mafic in nature, composed of basalt rock and its coarse-grained equivalent, gabbro, both rich in iron, magnesium and calcium. In contrast, continental plates are felsic in nature, dominated by granitic rock with its abundant silica, aluminum, sodium and potassium.

Not including a sedimentary cover of variable thickness and composition, the oceanic crust consists of three layers: (1) a relatively thin uppermost volcanic layer of basaltic lavas known as mid-ocean ridge basalts (MORB) erupted on the seafloor; (2) a thicker layer of more coarsely crystalline, intrusive basaltic …

Oceanic crust is denser and thinner and mainly com​posed of basalt. Continental crust is less dense, thicker, and mainly composed of granite. The mantle lies below the crust and is up to 2900 km thick. It consists of hot, dense, iron and magnesium-rich solid rock….The core.