Introduction to Weathering and Soil Types lec 3

These flashcards cover key terms and concepts regarding weathering, soil types, and their characteristics as discussed in the provided lecture.

Weathering

The process of breaking down rocks, resulting in the formation of soil and sediment.

Biological Weathering

Weathering caused by the activities of organisms, such as plant roots and burrowing animals.

Paleosol

An ancient soil that has been preserved in the geological record.

Bowen's Reaction Series

A conceptual model that outlines the equilibrium of minerals as they crystallize from magma at different temperatures.

Climate

The long-term patterns of temperature, humidity, and precipitation in a given area that affect weathering rates.

Parent Rock

The original rock from which sediment is derived and which influences the soil formation process.

Sedimentary Structures

Features formed during the deposition of sediment, which can reveal information about past environmental conditions.

Porosity

The measure of the void spaces in a material, which affects how much fluid a material can hold.

Permeability

The ability of a material to transmit fluids through its pores.

Isotope

Different variants of a chemical element that have the same number of protons but different numbers of neutrons, used in geochemical analysis.

Sorting

The degree to which grain sizes are distributed evenly in sediment; well-sorted means similar sizes, poorly sorted means a range of sizes.

Physical Weathering

The mechanical process of breaking rocks into smaller fragments without changing their chemical composition, often through forces like frost wedging or thermal expansion.

Chemical Weathering

The process by which the internal structure of a mineral is altered by the removal and/or addition of elements, typically involving water ($H_2O$) and atmospheric gases.

Erosion

The transport of weathered rock and soil particles from one location to another by agents such as moving water, wind, ice, or gravity.

Lithification

The process where unconsolidated sediments are transformed into solid sedimentary rocks through compaction and cementation.

Oxidation

A chemical weathering process where oxygen ($O<em>2$) reacts with minerals, particularly those containing iron ($Fe$), to form oxides like hematite ($Fe</em>2O_3$).

Hydrolysis

A chemical reaction between mineral ions and the ions of water ($H^+$ and $OH^-$), resulting in the decomposition of the original mineral and the formation of new minerals like clay.

Soil Horizon

A specific layer within a soil profile ($O$, $A$, $E$, $B$, or $C$) that possesses physical and chemical characteristics differing from the layers above and below it.

Diagenesis

The collective physical, chemical, and biological changes that occur in sediment after deposition and during its transition to sedimentary rock, occurring at temperatures below approximately $200$ degrees Celsius.

Frost Wedging

A form of physical weathering where water enters cracks in rocks, freezes, and expands by approximately $9\%$ in volume, exerting pressure that breaks the rock apart.

Exfoliation

A physical weathering process, also known as sheeting, where large, curved slabs of rock peel off the surface of a rock mass due to the reduction in pressure as overlying rock is eroded.