Weathering Ch 12 Chemical Mechanical Weathering Weathering the

  • Slides: 16
Download presentation
Weathering Ch. 12

Weathering Ch. 12

Chemical & Mechanical Weathering • Weathering - the breakdown of rock. • Mechanical (PHYSICAL)

Chemical & Mechanical Weathering • Weathering - the breakdown of rock. • Mechanical (PHYSICAL) Weathering – breakdown of rock into smaller pieces by natural agents. • Chemical Weathering – breakdown or disintegration of rock by chemical reactions.

Rate of Weathering What affects the rate of weathering? 1. Surface exposure – how

Rate of Weathering What affects the rate of weathering? 1. Surface exposure – how long is the rock exposed to the elements (wind/water)? 2. Composition of Rock – what minerals is the rock made of? (Some minerals weather at different rates) 3. Climate – certain climates promote different types of weathering Wet climates favor chemical weathering (tropical) Dry climates favor mechanical weathering (deserts)

MECHANICAL & CHEMICAL WEATHERING FOLDABLE

MECHANICAL & CHEMICAL WEATHERING FOLDABLE

METHODS OF MECHANICAL WEATHERING

METHODS OF MECHANICAL WEATHERING

Mechanical Weathering: ICE/WATER • Frost/ice wedging – water gets into cracks, freezes and expands,

Mechanical Weathering: ICE/WATER • Frost/ice wedging – water gets into cracks, freezes and expands, thaws and contracts.

Mechanical Weathering: ABRASION • Water, wind, ice, and gravity move rock. As they scrape

Mechanical Weathering: ABRASION • Water, wind, ice, and gravity move rock. As they scrape against surfaces and move against each other they SCRAPE and wear them down. • “SANDPAPER”

Mechanical Weathering: PLANTS/ANIMALS • Root wedging - plant roots grow into rock and break

Mechanical Weathering: PLANTS/ANIMALS • Root wedging - plant roots grow into rock and break them. • Animals burrow into cracks of rocks and break them.

Animals weathering rock.

Animals weathering rock.

Mechanical Weathering: UPWARD EXPANSION • Uplift – upward force inside earth, causes rock to

Mechanical Weathering: UPWARD EXPANSION • Uplift – upward force inside earth, causes rock to break in layers parallel to surface known as exfoliation. • Thermal expansion – rocks are heated, expand contract, peeling off layers.

METHODS OF CHEMICAL WEATHERING

METHODS OF CHEMICAL WEATHERING

Chemical Weathering: CARBONATION • Carbonic acid (common acid dissolved in water) seeps through the

Chemical Weathering: CARBONATION • Carbonic acid (common acid dissolved in water) seeps through the ground and dissolves certain minerals. Dissolves CALCITE completely! • CALCITE is in limestone and marble.

Luray Caverns, VA

Luray Caverns, VA

Chemical Weathering: OXIDATION • Chemical reaction of OXYGEN (O) with other substances, especially IRON

Chemical Weathering: OXIDATION • Chemical reaction of OXYGEN (O) with other substances, especially IRON (Fe). • When O + Fe = rust.

Chemical Weathering: HYDROLYSIS • Water reacting with minerals by dissolving the ions in them

Chemical Weathering: HYDROLYSIS • Water reacting with minerals by dissolving the ions in them and reacting with the water to form clay minerals. • (FELDSPAR)

Chemical Weathering: BIOLOGIC BREAKDOWN • Plants/animals sometimes secrete acid which can chemically weather rock.

Chemical Weathering: BIOLOGIC BREAKDOWN • Plants/animals sometimes secrete acid which can chemically weather rock. • Moss/lichens

Weathering weathering mechanical weathering chemical weathering oxidation WeatheringWeathering weathering mechanical weathering chemical weathering oxidation Weathering
Weathering weathering mechanical weathering chemical weathering oxidation WeatheringWeathering weathering mechanical weathering chemical weathering oxidation Weathering
Weathering Weathering Vocabulary Weathering Physical Weathering Chemical WeatheringWeathering Weathering Vocabulary Weathering Physical Weathering Chemical Weathering
Weathering Erosion Differential Weathering Chemical Weathering Mechanical PhysicalWeathering Erosion Differential Weathering Chemical Weathering Mechanical Physical
Weathering and Erosion Mechanical Weathering Chemical Weathering ExamineWeathering and Erosion Mechanical Weathering Chemical Weathering Examine
WEATHERING WEATHERING Nature of weathering and erosion WeatheringWEATHERING WEATHERING Nature of weathering and erosion Weathering
Weathering No atmosphere no weathering Mechanical Weathering ExamplesWeathering No atmosphere no weathering Mechanical Weathering Examples
Weathering Weathering Physical mechanical weathering The process byWeathering Weathering Physical mechanical weathering The process by
Weathering and Erosion Objectives Define weathering mechanical weatheringWeathering and Erosion Objectives Define weathering mechanical weathering
Chapter 4 Mechanical Weathering What is Weathering WeatheringChapter 4 Mechanical Weathering What is Weathering Weathering
Mechanical Physical Weathering Mechanical Weathering The breakdown ofMechanical Physical Weathering Mechanical Weathering The breakdown of
Weathering and Soil Types of Weathering Chemical WeatheringWeathering and Soil Types of Weathering Chemical Weathering
Introduction to Weathering Chemical Weathering Physical Weathering RatesIntroduction to Weathering Chemical Weathering Physical Weathering Rates
WEATHERING PROCESSES Physical and Chemical Weathering Weathering insituWEATHERING PROCESSES Physical and Chemical Weathering Weathering insitu
Chemical Mechanical Weathering How is soil formed WeatheringChemical Mechanical Weathering How is soil formed Weathering