Weathering October 2016
Process by which rocks are broken down physically or chemically Weathering Process by which rocks are broken down physically or chemically
Mechanical Weathering Rock is physically (something hitting it) broken down into smaller pieces.
Mechanical Weathering What are the agents (causes) of mechanical weathering?
Causes of Mechanical Weathering *Ice (ice wedging- freezing / thawing of H2O breaks rock *Wind (wind blows sand against rock and it breaks down) *Water (water moves rock against rocks and they break - river rocks) *Gravity (gravity moves rock down a hill and it breaks rocks) Living Things (plant roots or animals burrowing) *Abrasion - the grinding of rock by other rock carried by wind, water, gravity, or ice.
Rock breaks down through chemical reactions. Chemical Weathering Rock breaks down through chemical reactions. https://www.youtube.com/watch?v=fUga-cw-L2E
What are the agents (causes) of chemical weathering?
Agents of Chemical Weathering (Weak Acids) Water (dissolves rock over LONG periods of time) Acid Precipitation (rain, snow, sleet, or hail with acid from fossil fuels) Acids in Groundwater (carbonic acid in caves) Acids in Living Things (lichens produce acids) Air (oxygen reacts with iron in rocks to create rust – oxidation)
Mechanical AND Chemical Weathering (plant roots push and make acid, water) http://humanities.cqu.edu.au/geography/GEOG11023/week_5_textbook.htm
Mechanical Weathering (ice) http://www. kidsgeo
Mechanical Weathering (Wind by abrasion) http://adorons
Chemical AND Mechanical Weathering (plant acid and plant roots) http://www.earth.ox.ac.uk/~oesis/field/index.html
Mechanical Weathering (wind and abrasion) http://www. uh
Chemical Weathering (acid precipitation) http://marlimillerphoto
Chemical Weathering (acid precipitation) http://www. ux1. eiu
Chemical Weathering (acid in groundwater) http://www. cartage. org
Chemical Weathering (acid in living things - lichens) http://www
Chemical Weathering AND Mechanical Weathering (wind and oxidation – rust) http://www.cartage.org.lb/en/themes/sciences/earthscience/geology/soils/FormationSoils/WeatheringSoils/ChemicalWeathering/chemicalweathering.htm
What affects the rate rock weathers? Type of Rock Mineral composition – some minerals dissolve faster than others. Permeable rock weathers easily because made of small air pockets. Climate (average weather condition) Wet, high climates = faster weathering Dry, cool climates = slower weathering