Tectonic Plates Key Terms

?
  • Created by: ella.cook
  • Created on: 13-03-17 19:34
Moho
Short for Mohorovicic discontinuity, the boundary between the crust and mantle. It lies at c35km beneath the continents and 10-15km beneath the ocean floor
1 of 42
Asthenosphere
The layer in the Earth's mantle below the lithosphere. The high temperatures cause the rocks to soften and become viscous meaning they easily deform
2 of 42
Lithosphere
Layer in the Earth's mantle above the asthenosphere together with the crust which is divided into a series of tectonic plates. It's rigid and moves by flows of semi-molten rock in the asthenosphere.
3 of 42
Continental Drift
The theory that the continents are mobile and have moved across the Earth's surface through geological time.
4 of 42
Palaeomagnetism
Traces of changes in the Earth's magnetic field in the alignment of magnetic minerals in sedimentary and igneous rocks.
5 of 42
Benioff Zone
Boundary between a subducting ocean plate and the over-riding continental plate at a destructive boundary.
6 of 42
Black smoker
Hydrothermal vent on the ocean floor at constructive or destructive plate boundaries. The water carries high amounts of metal sulphides.
7 of 42
Caldera
Large-scale volcanic crater formed as a result of an explosive eruption which emptied the magma chamber causing the volcano sides to subside.
8 of 42
Continental shelf
The gently sloping offshore extension of a continent extending into the ocean as far as the continental slope
9 of 42
Continental slope
Where the continental shelf becomes steeper as it descends into the ocean.
10 of 42
Convection
The motion of a gas or liquid which when warmed rises until eventually it cools and sinks in a continuous circulation.
11 of 42
Cumuliform cloud
A cloud formed by convection with a rounded-top, lumpy appearance and flat base.
12 of 42
Denundation
The wearing away of the Earth's surface by weathering and erosion
13 of 42
Dyke
A vertical or near vertical minor intrusion of magma through surrounding older rocks
14 of 42
Earthquake focus
A point in the crust where rocks fracture, releasing energy.
15 of 42
Effusive eruption
A gentle, free-flowing basic eruption of lava, e.g. basalt
16 of 42
Epicentre
Point at the surface directly above an earthquake focus
17 of 42
Explosive eruption
A violent eruption owing to the build-up of pressure within a volcano, due to viscous magma preventing the escape of gases
18 of 42
Ferrous minerals
Minerals with a significant iron content.
19 of 42
Flood basalt
A large area of basaltic lava erupted over a long (thousands of years) from multiple vents e.g.the Deccan Plateau.
20 of 42
Guyot
Flat-topped seamount with its summit well below the ocean surface. Many appear to have volcanic origin, having formed at ocean ridges.
21 of 42
Hot spot
An area of intense volcanic activity where a mantle plume reaches the Earth's surface causing eruptions. Located away from plate boundaries e.g. Hawaii
22 of 42
Hydrothermal vent
Very hot water springs, rich in dissolved minerals, flowing from the ocean floor at mid-ocean ridges or hot spots
23 of 42
Isostatic
Relating to vertical movements of the Earth's crust
24 of 42
Jokulhaulps
Extreme glacial meltwater outbursts caused be geothermal or volcanic activity beneath glaciers.
25 of 42
Mid-ocean ridge
The boundary between two diverging oceanic plates. It consists of two parallel chains of submarine mountains separated by a graben, and offset in places by transform faults.
26 of 42
Modified Mercalli Scale
A subjective measure of earthquake intensity using factors such as what was felt by people and the type and scale of damage to buildings and infrastructure.
27 of 42
Moment Magnitude Scale (Mw)
A measure of earthquake strength using the amount of physical movement caused by a quake.
28 of 42
Ocean trench
Narrow deep depression on the ocean floor adjacent to a subduction zone.
29 of 42
Phreatic
An eruption of steam from a volcano caused when groundwater meets magma.
30 of 42
Pillow lava
Rounded mounds of lava erupted along mid-oceanic ridges, which cool rapidly on contact with water
31 of 42
Richter Scale
System measuring the magnitude of an earthquake by using the energy released when overstrained rocks suddenly fracture. Uses a logarithmic scale, with just over 9.0 being the largest quake measured to date.
32 of 42
Rift valley
A valley formed by downfaulting between parallel faults. On land and along mid-ocean ridges.
33 of 42
Sea-floor spreading
Lateral movement of new oceanic crust away from a mid-ocean ridge (constructive plate boundary). A key process in continental drift theory.
34 of 42
Shield volcano
A volcano with a broad base and gently sloping sides. It forms from the effusive eruption of fluid basalt lava.
35 of 42
Strato-volcano
A steep-sided volcano made up of layers of lava and ash emitted during explosive eruptions. Also known as a composite cone.
36 of 42
Subduction
The tectonic process found at convergent plate margins where an oceanic plate descend into the Earth's mantle and is destroyed.
37 of 42
Super-volcano
A volcano that erupts more than 1000km of material in a single eruption event.
38 of 42
Transform faults
Large-scale faults in the crust at right angles to a mid-ocean ridge, which ranges from a few tens of km's to several hundred. Earthquakes occur along their lengths as they slip.
39 of 42
Upper mantle
The layer of the Earth's interior extending 75-200km below the surface. The upper mantle is able to flow under pressure.
40 of 42
Viscosity
An indication of how well a substance flows. Acid lavas have high viscosity as they are sticky and don't flow far from a vent.
41 of 42
Volcanic Explosivity Index (VEI)
Combines magnitude and intensity of an eruption on a logarithmic scale, 0=least explosive, 8=most explosive.
42 of 42

Other cards in this set

Card 2

Front

The layer in the Earth's mantle below the lithosphere. The high temperatures cause the rocks to soften and become viscous meaning they easily deform

Back

Asthenosphere

Card 3

Front

Layer in the Earth's mantle above the asthenosphere together with the crust which is divided into a series of tectonic plates. It's rigid and moves by flows of semi-molten rock in the asthenosphere.

Back

Preview of the back of card 3

Card 4

Front

The theory that the continents are mobile and have moved across the Earth's surface through geological time.

Back

Preview of the back of card 4

Card 5

Front

Traces of changes in the Earth's magnetic field in the alignment of magnetic minerals in sedimentary and igneous rocks.

Back

Preview of the back of card 5
View more cards

Comments

No comments have yet been made

Similar Geography resources:

See all Geography resources »See all Plate tectonics resources »