Geology Chapter 5 Summary

Rocks weathered by mechanical and chemical weathering

Weathering processes produce spheroidal weathering, differentially weathered landforms, sheet joints, and exfoliation domes

Mechanical weathering (Physical disintegration) = breaking rock into smaller pieces. little or no chemical

Frost action = mechanical effect of freezing water on rocks (occurs as frost wedging)

Pressure Release = reduction of pressure on the body of the rock cause it to crack as it expanded

By exposing more surface area of rock mechanical weather can speed up Chemical weathering

Chemical weathering = decomposition or rock from exposure to water and atmospherics gases. Mineral’s components recombine into new minerals that are more in equilibrium

Carbonic Acid = weak acid mixed with water and Carbon Dioxide. Most effective in chem weathering

Calcite dissolves when it’s chemically weathered.

What mineral form clay minerals when chemically weathered? Silicate minerals

What mineral is most resistant to chemical weathering? Quartz

Residual Soil = develops from weathering of bedrock beneath them. Local soil.

Transported soil = doesn’t develop from locally formed rock but from regolith/rocks brought from other regions.

Soil Horizons = soil layers. distingusihed by appearance and chem composition 

What is the most important factor determining soil type? Climate

Facotrs that affect soil type: Parent material, time, slope, organic activity, climate

Rates of Eorsion influenced by: soil characterisitics, climate, slope, and vegetation 

What are the soil horizons? O, A, E, B, C,

What is the composition of O horizon? Consists entirely of Orgnaic materials such as decomposed leaves, animals. May contain humus.