Science Grade 10 Quarter 1 Lesson 2

Plate boundary

These plates are all moving in different directions and different speeds the place where two plates meet called

Alfred Wegener

the father of the plate tectonics theory

Driving mechanism

aspect of the plate tectonics theory explains how tectonic plates are able to move across the Earth's surface

Lithosphere

The brittle, solid part of Earth

asthenosphere

It is a ductile layer under the solid lithosphere. It is primarily composed of rocks that are partly molten due to high temperature and pressure under the lithosphere.

convection current

is divided into cells that move in the opposite direction. Hot molten materials move up whereas cooler materials move down.

plate margins

also known as plate boundaries, are of three types, namely, convergent, divergent, and transform. Each plate boundary forms different geological features.

convergent boundaries

This is where two plates are colliding Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust.

Where oceanic crust meets ocean crust

Island arcs and oceanic trenches occur when both of the plates are made of oceanic crust.These are often associated with submarine volcanoes.

Where oceanic crust meets continental crust

The denser oceanic plate is subducted, often forming a mountain range on the continent. The Andes is an example of this type of collision.

Where continental crust meets continental crust

too light to subduct so a continentcontinent collision occurs, creating especially large mountain ranges. The most spectacular example of this is the Himalayas.

Subduction

is a geological process that takes place at convergent boundaries of tectonic plates where one plate moves under another and is forced to sink due to high gravitational potential energy into the mantle.

subduction zones

Regions where this process occurs are known as

Divergent Boundaries

This is where two plates are moving apart each other. The space created can also fill with new crustal material sourced from molten magma that forms below.

fracture

Resulting in the production of new seafloor. As the plate moves opposite each other, it causes a __ in the lithosphere, resulting in the upwelling of hot molten materials.

mid-oceanic ridges

The most active divergent plate boundaries are between oceanic plates and are often called

rifts

Divergent boundaries within continents initially produce

rift valley

is another feature that results from plate movement. As plates move apart, they create a depression or a lowland region along the separation of the plates

The Great Rift Valley of Africa

is an example of this rifting due to tectonic movement.

transform boundaries

This is where plates slide passed each other

destroyed nor created

The relative motion of the plates is horizontal. They can occur underwater or on land, and crust is neither

earthquake

Because of friction, the plates cannot simply glide past each other. Rather, stress builds up in both plates and when it exceeds the threshold of the rocks, the energy is released - causing

convection current

is thought to be the driving mechanism for plate movements.

asthenosphere

Even though the mantle is solid, a part of it called the ___ flows like a soft and pliable plastic.

heat transfer

Convection currents are an important form of

photosphere

In the sun, convection occurs when opaque gas absorbs energy emitted by fusion, heats up, and rises to the ___ where the energy is radiated into space.

convection

also occurs in a pot of boiling water, or a convection oven