What are the key elements of the structure of the Earth? Lithosphere What are the key elements of the structure of the Earth?

Lithosphere: rocky layer of earth including the crust and upper mantle Lithosphere: rocky layer of earth including the crust and upper mantle. The lithosphere is broken up into several plates that slide laterally as a result of convection currents.

Three ways that energy can be transferred: radiation, conduction, and convection. Convection is the movement of heat (thermal energy) from one part of a fluid to another.

Convection current: the rising of hot fluid and falling of cooler fluid resulting in cyclical motion.

Convection currents are responsible for plate tectonic movement Convection currents are responsible for plate tectonic movement . Continental drift – theory which explains why continents shift position.

Earth, Terra, Jorde, Gaia has four layers of significance: crust, mantle, outer core, inner core.

Evidence for continental drift: comparative fossils, comparative flora, mid-ocean ridges, paleomagnetism, geological fit.

Comparative fossils. Similar brachiopod fossils have been discovered in both Australia and India.

Comparative fossils. The fossil remains of mesosaurus, a reptile, has been discovered in both South America and Africa.

Comparative flora. The fern, glossopteris, is native to Africa, Antarctica, South America, AND Australia.

Mid-Ocean Ridge. Underwater mountain range formed when magma rises through diverging plates. The ridge is therefore evidence that the plates are moving, albeit slowly.

Jigsaw Fit: the similarity in outline of the continental coastlines Jigsaw Fit: the similarity in outline of the continental coastlines. Geological fit: the terrain features of one continent appear to match the terrain features of another.

Paleomagnetism: the ancient alignment of rock and magma minerals with the Earth’s magnetic field.

Paleomagnetism Analysis Process Magma (liquid rock) forms near the core. Minerals align with Earth’s magnetic field. The magnetic field reverses. Minerals align themselves with the new field. This creates bands of minerals aligned in different directions.

Oceanic crust: outermost layer of Earth’s lithosphere found under the oceans and formed at mid-oceanic ridges.

Continental crust: less dense and thicker than oceanic crust, formed in subduction zones.

Subduction zone (destructive plate boundary): area of plate collision where the more dense plate follows a path underneath the less dense plate.

Divergent zone (constructive plate boundary): locations where plates move away from one another. This occurs above rising convection currents.

conservative plate boundaries: occur when plates slide past each other in opposite directions, but without creating or destroying lithosphere.

Seismic waves are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. They are the energy that travels through the earth and is recorded on seismographs.

P wave or primary wave: fastest kind of seismic wave P wave or primary wave: fastest kind of seismic wave. can move through solid rock and fluids. particles move in the same direction that the wave is moving in.

S wave or secondary wave: slower than a P wave and can only move through solid rock; not liquid. S waves move rock particles perpendicular to the direction that the wave. It is this property of S waves that led seismologists to conclude that the Earth's outer core is a liquid.