EARTH SCIENCE:
Weathering: the change in the physical form or chemical
composition of exposed rock on the earth’s surface.
2 types:
Mechanical Weathering: involves processes that break rock
into smaller pieces without changing its chemical composition.
Chemical Weathering: are processes that break rock by changing its chemical composition.
Mechanical Weathering: Agents
1. Ice:
2. Living Organisms:
3. Gravity:
4. Running water:
5. Wind:
Chemical Weathering (decomposition) occurs when chemical
reactions take place between minerals in the rock and water, carbon
dioxide, oxygen, and acids.
Original minerals>>>>>>>>>>>>>New
minerals
1. Water: a. Hydrolysis
b.Leaching
2. Carbon Dioxide: Carbonation
3. Oxygen: Oxidation (corrosion)
4. Plant Acids
Weathering: very slow process.
Soil Formation:
Regolith and Bedrock
Weathering >>>>>>>>>>>>>Regolith
into soil (rock particles + mixture of minerals+water+gases+and
humus) Humus is part of well developed soil.
Soil Profile: Cross section of the soil: each Profile is composed of layers that are called horizons.
A Horizon: topsoil
B Horizon: subsoil
C Horizon: partially weathered bedrock
Climate is the most important factor influencing soil formation.
Tropical climates: Great rainfall====high rate of leaching
Desert climates: Low rainfall=====slow weathering rate=sandy soil
Temperate climates: Well developed soil, all layers present
Erosion:the process of transporting weathered products.
Agents:
1. Gravity: Mass movement
Fast:=rock fall,landslides,mudflows
Slow:=creep and slump
2. Running Water:
3. Ocean waves and currents:
4. Wind:
Peneplains:
Plateuas>>>>>>>>>>>>>>mesas>>>>>>>>>>>>>>buttes