Topic Keywords 2

What is the Earth structure?

It’s defined by compositional layers - crust, mantle and core (inner and outer).

What are internal energy sources?

The heat and pressure generated from within the Earth, which drive tectonic (geophysical hazards).

What is plate tectonic theory?

That the Earth’s solid outer shell (lithosphere) is divided into several large, rigid plates that glide slowly over the ductile semi-molten asthenosphere beneath.

What are tectonic plates?

Massive, irregular slabs of the Earth’s solid lithosphere (crust and upper mantle) that float on the semi-molten asthenosphere.

What is plate movement?

The slow, continuous movement of the Earth’s rigid lithospheric plates over the semi-molten asthenosphere.

What is gravitational sliding?

A plate tectonic process where gravity causes young, less dense and elevated oceanic lithosphere to slide down from a constructive plate margin.

What is ridge push?

A proposed mechanism for plate movement at constructive margins, where gravity acts on the less dense lithosphere at a mid-ocean ridge.

What is slab pull?

A primary driving force of tectonic plate movement, where cold, dense oceanic lithosphere sinks under its own weight into mantle at subduction zones.

What are convection currents?

In the mantle. Circular, heat driven movements of semi-molten magma, acting as a ‘conveyor belt’ for tectonic plates.

What is seafloor spreading?

A geological process, occurring at constructive plate margins where new oceanic crust is created as tectonic plates diverge.

What are destructive plate margins?

When 2 tectonic plates move toward each other, causing denser oceanic plate to subduct beneath lighter continental crust.

What are constructive plate margins?

When 2 tectonic plates move apart, typically at 2cm a year, causing magma to rise from the mantle to fill the gap.

What are conservative plate margins?

The boundary where tectonic plates slide past eachother, either in the opposite direction or same at different speeds.

What are landforms?

Natural features of the Earth’s surface shaped by physical processes, such as erosion, deposition or tectonic activity.

What are young fold mountains?

Relatively recent formed mountain ranges - particularly within last 10-5 million years.