ENVIRON 102 Chapter Notes - Chapter 7, Mod 2-3: Basalt, Igneous Rock, Continental Crust
10 May 2018
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Chapter 7: Ecosystem Ecology
7.2 The Rock Cycle
Elements within crust and mantle are converted from one type of rock to another
o Forces of plate tectonics (ex: weathering, erosion, and deposition)
High temperatures and pressure rocks melt and form magma magma cools and forms
igneous rock
o IGNEOUS: characteristics depend on chemical composition of magma and rate of cooling
▪ Mantle magma cool into rocks with iron and magnesium
▪ Continental crust magma cool into rocks with aluminum and silicon
▪ Magma cooled under surface forms intrusive igneous rock (ex: granite)
• Rough granular texture – a lot of time to grow large
▪ Magma cooled on surface forms extrusive igneous rock (ex: basalt)
• Cools rapidly – small crystals
Weathering (rocks breaking into smaller particles) is often caused by a combination of physical
and chemical processes
o Flowing water, ice, wind, gravity, plant roots/chemicals, carcass chemicals
o Broken up rock create soil
Erosion: weathered rock and soil are carried away by gravity, wind, water, or glacial ice
o Eventually deposited as sediment
o Minerals glue sediment together to form rock – SEDIMENTARY rock
SEDIMENTARY: characteristics depend on the sediment
o Ex: Shells/skeletons of marine organisms are rich in calcium and form limestone
METAMORPHIC rocks form when sedimentary and igneous rock are under high temperatures and
pressure (due to tectonic processes)
o Ex: shale slate; limestone marble
Release of nutrient elements
7.3 The Hydrologic Cycle
Hydrologic cycle: distribution and flux of water through Earth’s biogeochemical system
Three phases: solid ice, liquid water, and gaseous water vapor
Liquid water on ground
o Evaporate into atmosphere
o Flow across surface into streams and lakes and oceans
o Percolate through soil and become groundwater
Evaporation from leaves: transpiration
Runoff: rainwater that falls on land and eventually enters lakes and streams
Groundwater: water that is pulled by gravity down into the soil and rocks
o Aquifer: layers of soil or rock saturated by groundwater
o Moves at less than 1 ft per year
Earth’s liquid water carries dissolved molecules and sediment
Raindrops pick up chemicals in the atmosphere
Hydrologic cycle is important to the cycling of nutrient elements
Human activity
o Diverted water from rivers/streams for agricultural/industrial/residential uses
o Deforestation and pavements altered amounts of water in each step of cycle
o Taking water from aquifers faster than replenishment
o Worldwide climates are warming and glacial ice is melting
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Document Summary
Elements within crust and mantle are converted from one type of rock to another: forces of plate tectonics (ex: weathering, erosion, and deposition) Weathering (rocks breaking into smaller particles) is often caused by a combination of physical: flowing water, ice, wind, gravity, plant roots/chemicals, carcass chemicals, broken up rock create soil. Erosion: weathered rock and soil are carried away by gravity, wind, water, or glacial ice: eventually deposited as sediment, minerals glue sediment together to form rock sedimentary rock. Sedimentary: characteristics depend on the sediment: ex: shells/skeletons of marine organisms are rich in calcium and form limestone. Metamorphic rocks form when sedimentary and igneous rock are under high temperatures and pressure (due to tectonic processes: ex: shale slate; limestone marble. Hydrologic cycle: distribution and flux of water through earth"s biogeochemical system. Three phases: solid ice, liquid water, and gaseous water vapor.
