Unit 11: Geology and Earth’s Structure

Lithosphere

Outermost layer of Earth composed of tectonic plates that ‘float’ on the mantle.

Asthenosphere

Softer region under the crust that causes plate movement due to convection currents.

Divergent Boundaries

Plates move apart, creating new crust, typically found at mid-ocean ridges.

Convergent Boundaries

Plates collide, which can cause mountains to form, as well as subduction zones.

Transform Boundaries

Plates slide past one another, leading to earthquakes, such as along the San Andreas Fault.

O Horizon (Organic)

Surface litter layer that includes decomposing leaves and organic matter.

A Horizon (Topsoil)

Layer that mixes humus and minerals, crucial for plant growth.

Soil Erosion

Loss of soil caused by wind, water, and poor farming practices.

Surface Mining

Method of mining that removes surface layers to access shallow ore deposits.

Open-Pit Mining

Excavating a large pit to extract ore that is near the surface but extends deep.

Underground Mining

Involves tunnels or shafts to access deeper ore, with less surface disturbance.

Ore Processing (Refining)

The process to separate valuable minerals from waste rock, involving crushing and chemical methods.

Acid Mine Drainage (AMD)

Water pollution caused by the leaching of harmful substances from abandoned mines.

Reclamation

The process of restoring disturbed land to its original or stable condition.

Overburden

Soil and rock removed to access ore during mining.

Gangue

Non-valuable part of ore that is discarded as tailings.

Tailings

Residues from ore processing, potentially toxic due to heavy metals or chemicals.