weathering & soils

nonrenewable

A natural resource that is not replaced in a useful time frame

not all the rocks that appear at the surface are formed at the surface. After uplift from their environment of formation, rocks are changed into a form that is...

STABLE under the new conditions of earths surface through weathering

weathering & soils film

This film shows a summary of weathering processes at the Earth's surface, its role in the formation of soils and the relevance of soil in the maintenance of terrestrial life. Make sure you know the differences between mechanical and chemical weathering and how these two different forms of weathering work together. The various factors that influence mechanical and chemical weathering are analyzed. Although weathering is a natural process, human activities can accelerate it to the detriment of living creatures. The formation of soil is a consequence of weathering. The importance of soil for the terrestrial food chain is described in the rest of the film as well as the way in which human activities disrupt natural processes and cause erosion. The final part focusses on a case story, emphasizing the agents of erosion and the strategies to mitigate the problems.

rain water seeps down through the A-horizon and leaches away some of the soil material down to the B horizon, the next layer where the leached material are ...

accumulated

The billions of tons of CO2 nitrogen oxides and SO2 added every year from the burning of fossil fuels and forests combine chemically with rain water creating solutions many times more acidic than natural rain. The effect of this kind of precipitation created a global environmental problem known as ...

acid rain

the minerals most unstable and that weather the fastest at the Earth's surface are those that form at the ... temperatures. (REMEMBER BOWEN'S SERIES FOR THIS !)

at the highest temperatures

In very wet. tropical, climates, ... is the dominant form of weathering, enhanced by the abundance of water and the high ...

chemical & temperature

basalt decomposes more rapidly to ... minerals and iron compounds

claim

The most important source of acid rain is the SO2 emitted by automobiles and from industries and power plants burning high sulfur ...

coal

what combination of factors produced the famous Dust Bowl of the 1930's?

drought conditions combined with high winds to blow the regions soil into massive swirling clouds of dust

granites often develop joints (fractures) oriented parallel to the ground surface because, at the surface, they are no longer under the high pressure which they were formed. Plates of granite peel off the surface of the outcrop, layer by layer, like the stripping of skins from an onion, in a process known as...

exfoliation

granite weathers into a sandy soil made up of grains. Clay in the soil comes from the weathering of ...

feldspars

soil conservation strategies:

in depth soil survey first - then can give the strategies...

by breaking rocks in smaller pieces, mechanical weathering ... the amount of exposed surface. This will ... the action of chemical weathering.

increases ... this hasens the chemical weathering of the entire rock

resources :

materials useful to humans

in dry climates, ... weathering is the dominant form of weathering

mechanical

^ this is also an example of ... weathering

mechanical weathering

As rainwater percolates through decaying vegetation and soil, it picks up ... and thus becomes more effective in decomposing the underlying rock

more acids

does mechanical weathering result in a change in the bulk chemical composition of the parent rock? Why?

no - it still consists of its original composition

what mineral is very stable at the Earth's surface?

quarts, hemotite

soil is the foundation upon which the entire ... depends

terrestrial food chain

renewable

those that are replemnished in a period of time within a human life - wood - can grow trees within 30 years so this is renewable can occur in less than a lifetime very doable

the A-horizon is the loamy ... found at the surface

top soil

the C-horizon, the bottom-most layer, is the zone where there are still fragments of the ...

underlying bedrock that is partially disintegrated and decomposed and scattered among the weathered material but still recognizable

the floor of a tropical rainforest is actually a rather ... soil. most of the nutrient in the rainforest is provided by the organic matter from the forest itself when it decays. When the rainforest is cut down, the humus is exposed to ...

unproductive - erosion, the loss of this nutrient source ultimately results in a barron wasteland

reserves :

useful materials after they have been found, measured and considered currently economic to mine - they are already identifies and are presently economic

what are the principal agents of chemical weathering?

water in the ground & moisture in the air usually these solutions are weakly acidic and are capable of causing the slow chemical decomposition of most rock making minerals

The break down of a rock into fragments or even into its minerals components by physical processes is called...

weathering

Does chemical weathering change the bulk chemical composition of the parent rock? Example:

yes - the rusting of metal the red rust on this nail is a different substance from the metallic iron from its core - one substance has changed into another the iron of the nail has combined with oxygen from the atmosphere to form rust