weathering (6) Flashcards
Weathering
The disintegration and decomposition of rock at or near the surface of Earth
Mechanical Weathering
The physical disintegration of rock, resulting in smaller fragments
Chemical Weathering
The processes by which the internal structure of a mineral is altered by the removal and/or addition of elements
Erosion
The incorporation and transportation of material by a mobile agent, such as water, wind or ice
Frost wedging
The mechanical breakup of rock caused by the expansion of freezing water in cracks and crevices
Joint
A fracture in rock along which there has been no movement
Sheeting
A mechanical weathering process that is characterized by the splitting off of slab like sheets of rock
Exfoliation Dome
A large, dome-shaped structure, usually composed of granite, that is formed by sheeting
Dissolution
The process of dissolving into a homogenous solution, as when an acidic solution dissolves limestone; a common form of chemical weathering
Oxidation
The removal of one or more electrons from an atom or ion. So named because elements commonly combine with oxygen
Hydrolysis
A chemical weathering process in which minerals are altered by chemically reacting with water and acids
Sheroidal Weathering
Any weathering process that tends to produce a spherical shape from any initially blocky shape
How is carbonic acid formed in nature?
When it rains
What occurs when carbonic acid reacts with calcite-rich rocks such as limestone?
Dissolution
What products result when carbonic acid reacts with potassium feldspar?
Clay-Kaolinite
List several minerals that are especially susceptible to oxidation and list two common products of oxidation.
Ferromagnesian silica, biotite, pyroxene, etc.
Rust, hematite and limonite
Differential Weathering
The variation in the rate and degree of weathering caused by such factors as mineral makeup, degree of jointing, and climate
Explain why granite and marble headstones weather differently.
Composition
Marble is made of calcite which is really susceptible to dissolution
How does climate influence weathering?
Fastest weathering occurs in areas that are warm and wet
Regolith
The layer of rock and mineral fragments that nearly everywhere covers Earth’s land surface
Soil
A combination of mineral and organic matter, water, and air; the portion of the regolith that supports plant growth
Humus
Organic matter in soil that is produced by the decomposition of plants and animals
Soil Texture
The relative proportions of clay, silt, and sand in a soil. A soil’s texture strongly influences its ability to retain and transmit water and air
Explain why soil is considered an interface in the Earth system.
Geosphere, Atmosphere, Hydrosphere, and the Biosphere come together
