Tectonic Theory

Question 1

Pangaea

Answer 1

Pangaea is a hypothetical super-continent that included all current land masses, believed to have been in existence before the continents broke apart during the Triassic and Jurassic Periods.

Question 2

Continental Drift

Answer 2

The gradual movement of the continents across the earth’s surface through geological time.

Question 3

Convection Currents

Answer 3

The movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.

Question 4

Igneous Rock

Answer 4

Igneous rock is formed through the cooling and solidification of magma or lava.

Question 5

Impermeable

Answer 5

Not allowing fluid to pass through.

Question 6

Lava Flow

Answer 6

A mass of flowing or solidified lava.

Question 7

Metamorphic Rock

Answer 7

Rock that was once one form of rock but has changed to another under the influence of heat, pressure, or some other agent without passing through a liquid phase.

Question 8

Plate Tectonic Theory

Answer 8

The theory that the outer rigid layer of the earth (the lithosphere) is divided into a couple of dozen “plates” that move around across the earth’s surface relative to each other, like slabs of ice on a lake.

Question 9

Sedimentary Rocks

Answer 9

Rock that has formed through the deposition and solidification of sediment, especially sediment transported by water (rivers, lakes, and oceans), ice (glaciers), and wind. Sedimentary rocks are often deposited in layers, and frequently contain fossils. An example would be Limestone.

Question 10

Asthenosphere

Answer 10

The upper layer of the earth’s mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.

Question 11

Wadati-Benioff Zone

Answer 11

A zone of seismicity corresponding with the down-going slab in a subduction zone. Differential motion along the zone produces numerous earthquakes, the foci of which may be as deep as about 670 kilometres.

Question 12

Inner Core

Answer 12

A solid sphere in the middle of the fluid core such as the iron-nickel core of the Earth.

Question 13

Crust

Answer 13

A crust is the outermost layer of a planet. The crust of the Earth is composed of a great variety of igneous, metamorphic, and sedimentary rocks. The crust is underlain by the mantle. The upper part of the mantle is composed mostly of peridotite, a rock denser than rocks common in the overlying crust.

Question 14

Lithosphere

Answer 14

The rigid outer part of the earth, consisting of the crust and upper mantle.

Question 15

Magma Chamber

Answer 15

A reservoir of magma within the earth’s crust beneath a volcano.

Question 16

Mantle

Answer 16

The mantle is made up of semi-molten rock called magma. In the upper parts of the mantle the rock is hard, but lower down the rock is soft and beginning to melt. The crust is the outer layer of the earth. It is a thin layer between 0-60 km thick.

Question 17

Moho

Answer 17

The boundary surface between the earth’s crust and the mantle, lying at a depth of about 10–12 km under the ocean bed and 40–50 km under the continents.

Question 18

Ocean Trench

Answer 18

A long, narrow, deep depression in the ocean bed, typically one running parallel to a plate boundary and marking a subduction zone.

Question 19

Permeable

Answer 19

Allowing liquids or gases to pass through it.

Question 20

Palaemagnetism

Answer 20

Concerned with the magnetism in rocks that was induced by the earth’s magnetic field at the time of their formation.

Question 21

Rayleigh-Benard Theory

Answer 21

The Rayleigh-Benard convection phenomena is an instability which basically occurs in a viscous fluid layer submitted to a vertical negative temperature gradient, in the same direction than the gravity.

Question 22

Tethys Sea

Answer 22

An ocean that existed between the continents of Gondwana and Laurasia during much of the Mesozoic era.