Catastrophism
The view that most of Earth’s geological features are the result of large-scale catastrophes such as floods, volcanic eruptions, etc.
Uniformitarianism
The view that most of Earth’s geological features are the result of slow, gradual processes that have been at work for millions or even billions of years
Humus
The decayed remains of once-living creatures
Minerals
Inorganic crystalline substances found naturally in the earth
Sedimentary Rock
Sediments (sand, silt, minerals, and other components of soil) that are laid down by water or some other agent
Igneous Rock
Rock formed from molten rock (magma)
Metamorphic Rock
Rock that has changed, usally due to heat and/or pressure
Lamination
When a single layer of rock is less than 1 centimeter thick
Weathering
The process by which rocks are broken down to form sediments
Unconformity
A surface of erosion that separates one layer of rock from another
Erosion
The process by which rock and soil are broken down and transported away
