Sedimentary Rocks and Weathering, Erosion, and Soil Vocab

Rock cycle

model that illustrates the origin of the 3 basic types of rocks & the interrelatedness of Earth’s materials and processes

Igneous rock

rock formed from the cooling and hardening (recrystallization) of molten (melted) minerals

Sedimentary rock

rock formed from weathered products of pre-existing rocks that have been transported, deposited, compacted, & cemented

Metamorphic rock

rock formed from the alteration of pre-existing rock under the influence of heat and pressure

Clastic (sedimentary)

sedimentary rocks that are made up of pieces of pre-existing rocks

Chemical (sedimentary)

sedimentary rocks that form by precipitation of minerals from water

Biologic/biochemical (sedimentary)

sedimentary rocks that form when living organisms die, pile up, and are then compressed and cemented together.

Erosion

the geological process in which earth materials are transported by natural forces such as wind or water.

Deposition

the geological process in which sediments, soil and rocks are added to a landform or landmass

Compaction

layers are squeezed together and any water mixed in with the sediments is forced out

Cementation

the hardening and welding of clastic sediments (those formed from preexisting rock fragments) by the precipitation of mineral matter in the pore spaces.

Mechanical weathering

also called physical weathering; it is a process that causes rocks to break down

Chemical weathering

breaking down of rocks by changing the molecular structure of rocks and soil.

Exfoliation

process in which large flat or curved sheets of rock fracture and are detached from the outcrop due to pressure release

Frost wedging

happens when water gets in crack, freezes, and expands

Regolith

the layer of unconsolidated rocky material covering bedrock

Soil

the upper layer of earth in which plants grow a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles

Soil horizon

a layer parallel to the soil surface whose physical, chemical and biological characteristics differ from the layers above and beneath.

Humus

the organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms

Bedrock

solid rock underlying loose deposits such as soil or alluvium.

Mass movement

bulk movements of soil and rock debris down slopes in response to the pull of gravity

Glacier

a slowly moving mass or river of ice formed by the accumulation and compaction of snow on mountains or near the poles

Alluvial fan

a fan-shaped mass of alluvium deposited as the flow of a river decreases in velocity.

Wind deflation

the removal of solid particles by wind

Wind abrasion

the process of friction caused by scuffing, scratching, wearing down, marring, and rubbing away of materials