Principles of Earth Science Unit 5: Whitmore

Weathering; climate; acids; frost

__________________ is the physical or chemical breakdown of rock

- All types of rocks can be subject to this

- _____________ is one of the most important factors

- some rocks like limestones dissolve very easily with _________ that are produced naturally

- __________ heaving can be a problem in climates with extremely cold temperatures

Physical; Chemical

Weathering:

- Mechanical or _______________

> Frost wedging

> Unloading

> Root wedging

> Abrasion

> Hydraulic action

> Cavitation

> WInd

> Fire

> Groundwater Sapping

- _____________

> Solution by carbonic acid

> "Rusting" of rocks

imploding; bubble

Hydraulic Action:

- the force of an _______________ cavitation ___________ can cause tremendous damage

Abrasion; wind

______________ by _________ is typically not a very important process

ventifact

an object that has been sculpted by the wind by the process of abrasion

Chemical

_______________ Weathering:

- Carbonic acid

> CO2 + H20 -> H2CO3

> Carbon dioxide and water make carbonic acid

> H2CO3 + CaCO3 -> Ca++ + 2HCO3

> Carbonic acid dissolves calcite to make calcium and bicarbonate ions

- Oxygen

> 4Fe + 3O2 -> 2FeO3

> Iron and oxygen combine to make rust

rust

If rocks have iron in them, they can ________.

Special; joints; patterns

____________ Types of weathering

- Spheroidal weathering

- Differential weathering

- Weathering in ___________ and streams controlled by joint _____________

resistant; easily; valleys

harder rocks are more ______________ to weathering and stand out, whereas softer rocks are ___________ eroded and tend to make ___________

soil

What is ________?

- Loose unconsolidated earth material resting on top of bedrock which can usually support plant growth

- contains both mineral and organic matter

- Mineral matter comes from weathered bedrock

- Loam is equal amounts of sand, silt, and clay (this is the ideal soil)

- Type and amount of soil is highly dependent on climate (water, bedrock type, heat, etc.)

stratified; O; A; E; B; C

- Soil is typically _______________

- Very general pattern

- The soil orders will vary depending on climate

- ____ horizon: thin layer of organic matter (lots of organics, masses of roots, dark in color, humus)

- ____ horizon: zone of leaching (top soil, mixture of organic and mineral matter, slightly darker)

- ____ horizon (zone of leaching below the A horizon)

- ____ horizon: zone of accumulation (sub soil, zone of accumulation from above materials)

- ____ horizon: partially altered to unaltered parent material (weathered pieces of bedrock)

climate; water

The type of soil and the horizons present are highly dependent on ___________ , slope, direction of __________ movement (up or down) and other factors

soil formation

Factors affecting _______ ______________:

- Parent material

> Residential soils vs. Transported soils

- Slope

- Living organisms

- Climate

- Time

duration; bedrock; climate

Weathering Factors:

- _____________ of weathering

- _____________ type

- _____________

- topography

layers; color; composition

Soil horizons and classifications:

- As soils mature, distinct __________ appear in them

- Soil layers are called soil horizons and can be distinguished from each other by __________ , chemical _________________ , and overall general appearance

climate; geology

Soil:

- There are 12 general soil orders and many suborders. Soil type usually has something to do with _____________ or _____________ .

> "Aridisols" are in deserts

> "Andisols" are formed from volcanic ash (andesite)

negatively; moisture; water drainage; positively

The importance of clay and quartz minerals in soils:

- clay is often ________________ charged and will attract water molecules to it

- clay helps old _______________ in soils

- Quartz grains are usually larger and help the soil to remain aerated and loose, allowing good __________ ______________

- clay minerals can also hold ________________ charged ions which are important as plant nutrients

- Plants can exchange H+ ions with Ca++ and K+, for example

abundant water; differently; complete

Chemical weathering and climate:

- Chemical weathering is most intense where there is _____________ __________ or in very humid climates

- The same rock will weather _______________ in different climates

> Weathering rates of sandstone and limestone in wet/dry climates

- Clay minerals and quartz are usually the only things left when the weathering process is _______________

resistant; easily

Climate difference and weathering

- In the desert west, limestones are very _____________

- the the humid east, limestones dissolve ___________

thickness; downward; upward

Soils and climate

- Climate effects soil ______________ and character

- Climates that are wet generally have thicker soils and are characterized by _______________ movement of water

- Dry climates are characterized by thin soils, little leaching, scant humus, and _____________ movement of soil water

tropical; high

Soils and climate

- Laterites

> Form in ___________ regions where temperatures and rainfall amounts are ________

> Soils are highly leached

> Usually red and composed of iron and aluminum oxides (neither are very soluble in water)

> Sometimes bauxite can form if the bedrock was rich in Aluminum. Bauxite is mined as a source of aluminum ore

> Laterites are often poor in nutrients and rather non productive

hardpan

Soils and Climate

- _____________ Soil

> General term for a hard layer of earth material that is difficult to drill or dig through

> Usually a clayey layer of cemented soil

> In arid climates this usually results from the formation of calcium carbonate and other minerals that form as the result of water evaporation

> "caliche"

soil development; Clay; carbonic

Chemical weathering and soil

- Chemical weathering of rock minerals is one of the main processes of ________ ___________________

- ________ minerals are produced from chemical weathering

- feldspar, mica, and ferromagnesian minerals all weather to clay under the influence of ________________ acid

- These processes produce other soluble products as well such as Na+, Ca++, K+, etc.

Residual; Transported

- _____________ Soils

> One that develops from the weathering of bedrock directly below it

> Typical situation

- _______________ Soils

> Soil that has not formed from the local rock

> Transported by water, wind, or ice

> floodplain soils

> Wind blown soils (sand, silt, loess)

> Glacial moraine

mass movement

_________ _________________: the down slope movement of rock, regolith, or soil under the influence of gravity. They can occur fast or slow

- Also called mass wasting

- Factors that influence mass movements:

> water

> slope

> Relief

> Vegetation (lack of)

> Seismic activity

> Rock type

Solifluction

occurs as the upper layer of permafrost thaws during the summer and moves down slope under the influence of gravity on top of the frozen soil

Oceans; freshwater

The Earth's water

- ___________: 96.5%

- Other saline waters: 0.9%

- _______________: 2.5%

> Glaciers: 68.7%

> Groundwater: 30.1%

> Lakes, streams, etc.: 1.2%

Hydrologic

The ________________ Cycle:

Important parts:

- Solar radiation (energy)

- Oceans

- Evaporation

- transpiration

- condensation

- clouds

- precipitation (rain/snow)

- glaciers (frozen water)

- Surface runoff (streams)

- Infiltration

- Groundwater

streams

the work of _____________:

- Streams do three primary types of work

> Erosion

> Transportation

> Deposition

- Most of the stream's work is done during periods of flooding or high water. Most deposition happens as water levels go down

erosion

___________: removal of weathered products

- We have talked a lot about these things already in the context of weathering

- What is the difference between weathering and erosion?

- Erosion methods of streams

> Abrasion

> Hydraulic action

> Solution by carbonic acid

> Cavitation

Abrasion

like sandpaper

hydraulic action

like a pressure washer

cavitation

like jackhammer bubbles

transportation

___________________:

- Bed load

> Sliding

> Rolling

> Saltation

- Suspended load

- dissolved load

Stream competence

____________ __________________:

- Stream competence refers to the largest particle that a stream can carry

- Factors affecting competence:

> Gradient (slope)

> Velocity

> Volume of water

> Density of fluid

> Channel characteristics

stream deposits

_____________ _______________:

- When material is deposited by a stream, competence goes down and the stream is no longer able to carry its load. The larger material gets deposited first, followed by smaller material as the competence continues to decrease

- Channel deposits

- Gravel bars

- Sand bars

- Point bars

- Flood plain deposits

- Alluvial fans

- deltas

Alluvial fans

_____________ ________:

- These deposits form in arid or semi-arid mountainous areas

- the deposits forms the result of a rapid decrease in competence as rivers come out of the mountains onto a very flat plain

- They are called "alluvial" because they are river deposits and "fans" because they have a triangular "fan" shape when viewed from above

river deltas

__________ ___________:

- These deposits form at the mouth of a stream as the stream enters into a lake or ocean

- the deposit forms as a result of a drop in competence

- have various shapes depending on stream load, tides and other factors

tributaries; mouth

- the drainage basin of a river is made up of all its ________________

- The ____________ of the river is the final destination of the river or when the river reaches base level

distributary channels

when a river breaks up into smaller rivers on the delta, these are called _______________ ______________

floods

_____________

- Most numerous and devastating type of natural disaster

- 1931 Chinese floods

> Years of drought

> Then heavy winter snows

> Then hit by 7 tropical storms

> Nearly 4 million people died

- 1993 Mississippi River flood

> Series of thunderstorms across upper Midwest during the summer

- Missoula flood (during the Ice Age, after Noah's flood)

> Failed glacial ice dam in Idaho

streams

types of _______________:

- Meandering

- Rejuvenated (also called entrenched or incised meanders)

- Braided

- Disappearing

- Misfit

Rejuvenation

__________________: caused by a drop in base level. This can be accomplished by uplift of the continent and/or a lowering of sea level

channeled scabland

the ________________ _______________ of Washington:

- In 1923, J. Harland Bretz proposed the scablands were formed by a catastrophic flood

- His theory was met with immediate criticism because of the enormity of the water required to makes the features

- his theory was not fully accepted until 1969

- he won the Penrose medal in 1980

Bretz's evidence

Channeled scablands

- ___________ _______________:

> Dry waterfalls with plunge pools 300 feet deep

> Hanging valleys

> Giant ripple marks with a wavelength of 200 to 500 feet and heights of 50 feet

> River gravel bars 400 feet high

> Upstream lake terraces and lake deposits (evidence for lake Missoula)

> The unexplained "scablands" topography (40,000 square kilometers in eastern Washington)

> Giant underwater delta at end of Columbia river

> Erratic boulders

> Giant potholes

> Tributaries plugged with huge gravel bars along the course of the Clark Fork River

proposed

Channeled scablands

- Bretz _______________:

> Amazon like river 9 miles wide and several hundred feet deep

> Lake Missoula (500 cubic miles of water)

> Dry falls were 3 times the height and 40 times the volume of Niagara falls

> Maximum flow of 30 meters per second

> discharge of 21 million cubic meters per second

hydrologic

the ________________ cycle:

- Important parts:

> Solar radiation (energy)

> Oceans

> Evaporation

> Transportation

> Condensation

> Clouds

> Precipitation (rain/snow)

> Glaciers (frozen water)

> Surface runoff (streams)

> infiltration

> groundwater

groundwater

what is ___________________?

- Terms to know:

> Vadose zone

> Capillary fringe

> Water table

> Saturated zone

- the water table is not flat, it gently contours the earth's surface above

- the higher parts of the water table flow to the lower parts

Porosity; permeability; aquifer

- ______________ is the amount or percentage of empty space that is contained within a rock. some rocks have higher than others

- ____________________ is the ability of a fluid to flow through a rock. Some rocks have higher than others

- in order to be a good _____________, groundwater must have both of these

impermeable; pollute

in modern landfills, the bottom of the landfill is lined with clay or shale to form an ________________ layer (a perched water table) so the fill does not _____________ the water table below

hot

_______ groundwater:

- Hot springs

- Geysers

- Fumeroles

- Mudpots

- Yellowstone Park has over 10,000 thermal features, 350 of which are geysers. There are only 550 geysers known in the world

Weathering

Process of larger rocks getting broken into smaller pieces

Erosion

Removal of the weathered products

Soil; mineral; organic

_______: Mixture of mineral and organic matter

- _____________: Can consist of various sizes of rocks (from fine particles to boulders) and chemically weathered products of rocks (clay)

- ______________: Contains various decay products of plants

Soil Horizons

Layers that typical soils are distributed into. usually have indistinct contacts between them, grading from one layer into another; will have varying thickness, mostly dependent on climate

O; humus

"____" horizon: Organic zone; contains dead and decaying plant and animal remains. Usually has masses of roots penetrating into the deeper layers

- normally dark in color (brown) because of the large amount of "_________" (organic material) it contains

A

"____" horizon: Contains a mixture of the organic material above and some mineral matter

- Darker normally than "O" horizon (brown or black)

- Below "O" horizon

- Most productive and nutrient-rich portion of any soil horizon

Loam

Soil the contains approximately equal amounts of clay,, silt, and sand

E

"____" horizon: zone of leaching below the "A" horizon

- Lighter in color than overlaying horizons

- Leaching happens in climates with a lot of rainfall and significant downward movement of water towards bedrock

- Poor in nutrients, rich in iron (red/orange in color)

B

"____" horizon: "subsoil"/"soil of accumulation"; consists of a variety of substances (organics, clay, small pieces of bedrock), most come from above

C

"____" horizon: Parent material; highly dependent on the type of bedrock below and usually consists of broken pieces of the underlying bedrock.

Chemical

______________ Weathering: Occurs when a rock disintegrates due to chemical reactions that happen within the environment

- carbonic acid is more common

Mechanical

______________ Weathering: The breakdown of rocks by physical or mechanical processes

wedging

frost ______________: If water gets into the cracks of rock and then proceeds to freeze, expanding and pushing the rock outward

heaving

frost ______________: Freezing water can lift (and crack) the road, causing damage that must be repaired

root

_________ wedge: Mechanical weathering where roots force open small fractures

- can lead to frost wedging

isostatic

_______________ rebound: If a large amount of rock is removed suddenly by erosion, or if a glacier melts and retreats, the force being exerted on the landscape will expand upward as a result of the lost material

pressure release; abrasion

______________ _____________ /Unloading: Rocks expand, having the same effect as pulling the rock apart. The rocks fracture, parallel to the surface

- When you smooth a piece of wood with sandpaper, you are using ____________ to remove the rough spots

Hydraulic

_____________ action: Breaking rocks apart by the sheer force of moving water

Cavitation

Special, but powerful mechanical weathering process. Occurs when fast moving water flows over small depressions in bedrock. Small bubble form and then implode. (Acts like a sledgehammer pointing on the rock)

sapping

Groundwater _____________: Occurs as groundwater pushes from the inside-out of a rock face. Pieces of rock weaken and fall

- Happens where a spring is flowing out of a rock

Spheroidal

_________________ weathering: When rocks (usually granites) are weathered into rounded shapes because at least 2 sets of perpendicular joints crisscross the granite. Mechanical/chemical weathering attacks joints and widens them.

differential

_________________ weathering: When one rock type weathers faster than another

wasting

Mass _____________: Mass movement; when large quantities of rock or soil move downhill under the influence of gravity, like landslides, rock falls, and slumps

- can be spectacular and rapid, or a slow process

Relief

Distance between the highest and lowest point in a landscape (the greater the relief, the greater likelihood of failure)

slope

the angle of the land surface (the higher the angle, the more likely it will fail)

mass wasting; undercut

4 types of ________ ____________ events:

1.) Falls

2.) Slides

3.) Slow Flows

4.) Rapid flows

- rockfalls and soil falls happen when material is _____________ , and a large section of the overlaying material drops through the air

talus

a large pile of debris at the base of a cliff

slides

general term used to describe rock or soil sliding down a slope

rock; slumps

__________ slides: can be a single block of material that slides down a hillside or they can be composed of many particles that slide all at once

- ___________: move along a curved/scoop-like surface

scarp

cliff face

creep

rock ____________: rocks that can slightly bend over time

- can occur in soil

solidification

happens in arctic areas where there is permafrost. The sun thaws the ground above frozen soil and turn it into mush

avalanches

rock _________________: involve large amounts of rock tumbling down a mountain side

- debris ________________: denser than the water they are moving in. Thick slurries generated by an earthquake which in turn causes mud and sand to flow downslope

currents

Density/turbidity ____________: denser than the water they are moving in. Thick slurries generated by an earthquake which in turn causes mud and sand to flow downslope

flows

earth __________: when soils and other materials become extremely water saturated and began to slowly flow downhill

mudflows

______________: large quantities of dry soil or volcanic ash are suddenly mixed with water.

- can float boulders and houses

- move quickly

hydrologic

________________ cycle: water cycle

groundwater

water found below the surface of the earth

hydraulic

________________ cycle: erosion by sheer force of moving water

solution

dissolving the rock

load; bed; suspended

weathered/eroded materials transported by streams

- _______ load: transported along bottom of stream

- _____________ load: carried in the water column

saltation

sand grain carried to end of stream. When it hits it causes other sand grains to get into current

dissolved

_________________ load: consists of various chemicals, salts, and pollutants dissolved in the water

competence

the ability of a stream to carry a load

channel

______________ deposits: deposits at bottom of a stream bed.

- form as a result of a drop in competence

levees

Natural ____________: Help confine the flow during flooding

distributaries

on a delta, the large stream splits into smaller river channels

meandering

________________ stream: one of the easiest types of streams to identify

point bar

__________ ______: Shallow inside portion of a meander bend