Changes cause thermal strain expansion and

This preview shows page 6 - 8 out of 11 pages.

changes cause thermal strain (expansion and contraction)UnloadingMechanical weather can also be produced by unloading; uplift and erosion reduces pressure (ex. exfoliation dome)DissolutionA common form of chemical weathering, it is the process of dissolving into a homoge-neous solution, promoted by acidic water (as when an acidic solution dissolves lime-stone forming sinkholes)Dissolution Chemical Formulas Form acid: CO2 + H2O = H2XO3 (carbonic acid) Attack minerals: CaCO3 + H2CO3 = Ca2+ + 2HCO3-Karst TopographyA type of topography formed on soluble rock (especially limestone) primarily by dis-solution… characterized by sinkholes, caves and underground drainageOxidationA chemical reaction that occurs when elec-trons are lost from one element during the reaction (often due to exposure to oxygen); Iron (most commonly affected) is released from ferromagnesian silicates HydrolysisThe reaction of a mineral or substance with water… a hydrogen ion attacks and replaces other ions LEO-GERLEO the Lion says GERLose an Electron = OxidationGain an Electron = Reduction Chapter 6: SoilsRegolith Layer of weathering products (rocks and mineral fragments) at the Earth’s surfaceSoilA combination of mineral and organic mat-ter plus water and air… it is the portion of the regolith that can support the growth of plants HumusAn essential part of soil that consists of de-cayed remains of animal and plant life (or-ganic matter) Parent Material The source of the weathered mineral matterfrom which soil develops Residual vs. Transported SoilResidual Soil: developed on bedrockTransported Soil: developed on unconsoli-dated deposits
Soil FormationThere are 4 factors that contribute to the formation of soil:Climate: most influential control, key factorsare temperature and precipitationTime: amount of time for soil formation varies for different soils depending on geo-logic and climatic conditions Plants and Animals: influence soil physical and chemical properties (ex. microorgan-isms, worms)Topography: steep vs. gentle slopesSoil ProfileSoil forming processes operate from the topdown, and the vertical differences are calledhorizons (zones or layers of soil)Soil Horizons O Horizon: the topsoil, consists of organic matter rich in humus… much biological ac-tivity A Horizon: organic matter mixed with min-eral material E Horizon: zone of eluviation and leachingB Horizon: zone of accumulation, accumula-tion of clay minerals (Fe oxides and calcite)C Horizon: partly altered parent rock, frag-ments mechanically weathered from bedrock and some partially decomposed Bedrock Unweathered parent rock Chapter 7: Sedimentary Rocks Forming Sedimentary RocksSedimentary rocks form from the com-paction, cementation and lithification of sediments:Compaction: compacting the stuff togetherCementation: cementing grains togetherLithification: making it a rock (the “rock”-ification process) Clastic vs. Non-Clastic Clastic: clastic (detrital) rocks are formed from mineral grains (clasts) bound together (cementation)-

Upload your study docs or become a

Course Hero member to access this document

Upload your study docs or become a

Course Hero member to access this document

End of preview. Want to read all 11 pages?

Upload your study docs or become a

Course Hero member to access this document

Term
Fall
Professor
BradleyCramer
Tags

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture