Weathering and Soils

weathering

physical breakdown and/or chemical alteration of rocks

erosion

removal of weathered material

physical/mechanical weathering

disaggregation of rocks via mechanical processes

chemical weathering

decomposition of rocks and minerals via chemical reactions

exfoliation

due to a reduction in confining pressure

thermal expansion

expansion and contraction due to heating and cooling, by extreme daily temperature difference

mechanical weathering does include…

frost wedging, thermal expansion, biological activity

what type of mechanical weathering process is associated with ‘‘peeling like an onion’’

exfoliation

chemical weathering

decomposed, dissolved, or loosened by chemical processes

dissolution

some minerals are dissolved in water

oxidation

iron+oxygen=rust

hydrolysis

minerals react with water in order to form other products

what acid chemically weathers Mammoth Cave (limestone)?

sulfuric acid

When granite is chemically weathered, K-feldspar

is converted into kaolinite

factors affecting weathering rate

surface area, rock characteristics, climate

surface area

chemical weathering INCREASES with the surface area

rock characteristics

different resistances or rocks and minerals to atmospheric processes, unstable minerals decompose

climate

affected by moisture and temperature, high weathering in warm and humid climate

in which climate, chemical weathering likely to occur most rapidly

tropical forest

which of the following minerals is most resistant to weathering in the conditions found on Earth’s surface

quartz

soil

layers of loose mineral and organic matter with water and air

regolith

rock and mineral fragments

humus

decayed animal and plant remains

the most influential control of soil formation

climate

what is a soil formed in tropical region and is rich in iron and aluminum and lack of organic material

laterite