Study Guide: Geology/Soil

Geology

The scientific study of the Earth, its materials, processes, and history.

Plate Tectonics

A unifying theory in geology that explains the movement of the Earth's lithosphere divided into tectonic plates.

Lithosphere

The outermost layer of the Earth, including the crust and upper mantle.

Crust

The chemically distinct outer layer of the lithosphere, composed of various rocks and minerals.

Mantle

The layer located above the core, containing semi-molten rock (magma) that flows slowly.

Asthenosphere

The upper part of the mantle, composed of semi-molten rock that allows for tectonic plate movement.

Core

The innermost zone of the Earth, consisting of a liquid outer core and a solid inner core, primarily made of iron and nickel.

Continental Drift

The hypothesis proposing that continents were once part of a supercontinent called Pangaea.

Sea-Floor Spreading

The process where new oceanic crust forms at mid-ocean ridges and is pushed away from the ridge.

Fossil Distribution

The occurrence of similar fossils on widely separated continents, indicating they were once connected.

Chemical Weathering

The process involving chemical reactions that alter the minerals within rocks.

Biological Weathering

The process occurring when living organisms contribute to the breakdown of rocks.

Soil Horizons

Layers in soil, including O Horizon, A Horizon, E Horizon, B Horizon, C Horizon, and R Horizon.

Cation Exchange Capacity (CEC)

The soil's ability to retain and supply cations (nutrient ions) to plants.

Base Saturation

The proportion of CEC occupied by nutrient cations, indicating soil fertility.

Rock Cycle

The continuous process of rock formation, alteration, and destruction involving igneous, sedimentary, and metamorphic rocks.

Earthquake

A sudden release of energy in the Earth's crust, causing vibrations.

Volcano

A geological structure formed when molten rock (magma) rises to the Earth's surface.

Weathering

The process through which rocks are broken down by physical, chemical, or biological processes.

Soil

A dynamic natural body of the Earth's surface that supports plant life.

Pedology

The study of soil formation, classification, and mapping.