TopicTopic

Physical and Chemical Physical and Chemical WeatheringWeathering

Weathering vs. ErosionWeathering vs. Erosion

WeatheringWeathering

----

ErosionErosion

----

Physical (Mechanical) Weathering

----

1) Frost Action1) Frost Action

•----•----

Temperature drops below

freezing

Expanding ice causes crack to become larger

Frost ActionFrost Action

Frost Action Causes Roadway Frost Action Causes Roadway PotholesPotholes

                        

      

No, it’s the L.I.E.

Potholes Potholes & &

Frost Frost HeavesHeaves

2) Organic Activity: --

Plant roots create a Plant roots create a channel for air and water channel for air and water to go into the rockto go into the rock

Niagara Glen, Niagara-on-the-Lake, Ontario, Canada

Root Action

Burns 2007

3) Exfoliation: ----

Exfoliation caused by:Exfoliation caused by:

Thermal expansionThermal expansion – ----– Very common in arid Very common in arid

areas like Southwest areas like Southwest U.S.U.S.

Geology 211, Physical Geology, ©, 2002, Ron Parker

Thermal ExpansionThermal Expansion

Physical changes in sediments -

Abrasion:

----

Formed by water abrasion

Formed by wind abrasion

Final Question:Name a location on Earth that has a considerable amount of frost action.

Topic: Chemical Weathering

Chemical WeatheringChemical Weathering--

**--** **--**

Solution - --Ex) Salt dissolving in water

Soluble – --Ex) Salt is soluble in water

Powerful Solutions:Powerful Solutions:

Acid RainH2O (rain) + CO2 (carbon dioxide) = H2CO3 (carbonic acid)

Result: *-- *--

The details of marble statues and The details of marble statues and tombstones will be gradually worn tombstones will be gradually worn away by dissolution. away by dissolution. Image courtesy of Dr. Annabelle Foos.Image courtesy of Dr. Annabelle Foos.

Karsts Topography

– forms caves,

caverns, and sinkholes

Stalagmites

Stalactites

The Witch's Finger, a stalagmite in the Carlsbad Caverns, NM

NPS photo by Peter Jones

Do you see Do you see the person the person

in this in this picture?picture?

Sinkhole FormationSinkhole Formation

Sinkhole—Winter Park, FLSinkhole—Winter Park, FL

Sinkhole at Winter Park, Florida (1981) that formed catastrophically in the time span of one day.  The city of Winter Park stabilized and sealed the sinkhole, converting it into an urban lake. 

2) Create Plant Acid2) Create Plant Acid

-- => ---- => --

----

Hydration

=>

•--

Oxidation –Oxidation –----

Ex) Iron + Oxygen = Iron Oxide (rust)Ex) Iron + Oxygen = Iron Oxide (rust)

Rust – Rust – Oxidation of IronOxidation of Iron

Oxidation Oxidation of Copperof Copper

FQ:

What rock dissolves to form stalactites in a cave?