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Define Weathering
All physical and chemical changes produced in rocks, at or near the earths surface, by atmospheric agents.
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What happens to primary minerals in weathering
Primary materials are broken down into secondary minerals
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What are the three primary rocks that are broken down via weathering
- Igneous
- sedimentary
- metamorphic
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What is ment by disintegration and decomposition in regards to the three rock types
- Disintegration is a physical breakdown of rocks into minerals
- Decomposition is the chemical breakdown of rocks into minerals
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After disintegraion what are two exapmples of minerals that are very slowly weatherd
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After disintegration what is an example of two minerals that are Slowly Weathered
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After disintegration what are three examples of minerals that are easily weatehered
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What happens to Quartz and Muscovite after continued disintegration
They become Resistant primary minerals
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What happens to Quartz and Muscovite after Alteration (Both phsycail and chemical)
Quartz and Muscovite become Silicate Clays
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What happens to feldspar and biotite after Decomposition and Recombination
They will become other Silicate Clays
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What happens to Calcite Augite and Hornblende After decompoisiton oxidation and hydration
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What can happen to Calcite, Augite and Hornblende when decmoposed
These can be decomposed into an aqeuous solution
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What happens to the three rock types after decomposition
Decomposition leads to the dissolvment of these three into an aqeuous solution
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What three alternatives can the three rock types in aqueous solution become
- Organic acid solution
- Hydrolysis
- Solution
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What becomes of the three rock types after they become an organic acid solution
- They form organic complexes of Al3+ and
- Fe3+
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What do the three rock types become after hydrolysis
Silicic acid
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What happens to the three rock types if they remain in solution
- They become soluble materials such as
- Ca
- Mg
- K
- Na
- Fe
- SO4
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What are the three types of Phsycial (AKA mechanical) Weatehring or disintegration
- Temperature
- Abrasion
- Plants and Animals
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What is ment by abrasion
Abrasion can be caused by the sand paper effect of sediments trapped in either water ice or in the wind which can then act to grind down pre existing rocks
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How much affect to plants and animals have on the disintegration of rocks
Plants and Animals have a minimal effect on the breakdown of rocks
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Besides physical weathering what other type of weathering is there?
- Chemical weathering AKA
- Biogeochemical weathering
- AKA
- Decomposition
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What three things enhances the effects of chemical weathering
- Geological
- Biological
- Plant
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What is ment by geological chemical weatehring
Water and ocygen acts to decompose rocks
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What is ment by biological chemical weathering
Microorganisms can create acids
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What is ment by plants chemical weathering
Plant root metabolism which i assume removes and adds CO2 i guess
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What is ment by Biogeochemical weathering
- Biogeochemical weatehring incorporates all of:
- Geological
- Biological
- Plant
- Chemical weathering
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Define Hydration in relation to Biogeochemical Weathering
Hydration - intact water molecule binds to a mineral
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Define Hydrolysis in biogeochemical weathering
Hydrolysis - Water reacts with a mineral with H+ Replacing a cation
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Define Dissolution in regards to biogeochemical weathering
Dissolution - Water dissolves minerals by dissolving ions
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Define Carbonation and other acid reactions in regards to biogeochemical weathering
Acids will accelerate the effects of weathering
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Define Oxidation and Reduction in relation to Biogeochemical weathering
The loss or gain of electrons in relation to oxygen availability
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Do weatehring proccess act alone?
No weathering proccess work together
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What does physical weathering do to increase biogeochemical weathering
Physical weathering disintegrates rocks which leads to an increased surface area for biogeochemical weathering to act on.
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Give an example of how biogeochemical weathering acts together
Hydrolysis can release Fe, Mn which can then be oxidized or reduced
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What cna soil colour say about a soil
Soil colour can give an idea of mineral content, movement of nutrients through soil as well as water content
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What is soil colour affected by
- Organc matter content
- Water content
- Presence of Fe Mn
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Waht colour of soil would iron oxides produce
Red Brown Grey Blue
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What colour of soil would we expect Manganese oxide to be
Black
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What colour fo soil would we expect Gluconite to be
Green
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What clour of soil would we expect Calcite to be
White
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Give an example of a Munsell Colour Chart Number
7.5YR 6/4
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Of 7.5YR 6/4 what represents Hue
Hue is the first value or 7.5 YR
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Of 7.5 YR 6/4 What represents Value
the Number 6 represents the Value number
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Of 7.5YR 6/4 what does the 4 represent
the 4 is the Chroma
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What is ment by Hue
Hue is a general colour range, Red, green yellow etc.
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Waht range can Value have? What does each extreme of the range represent
- Value is measured 0 - 10.
- 0 = pure Black
- 10 = Pure White
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What does a brown to black say about a soils attrbutes
A brown to Black says a high amount of organic material is present
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What does a black subsurface horizon represent
A Subsurface horizon of Black indicates a Manganese parent material such as basalt is present
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What does bright-light soil colour represent
The Eluvial horizon is present
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What does it mean in the environment when the E horizon is showing
- A showing E horizon means that an environment in which
- precipitation > evapotransperation
- meaning a leaching of sequoxides has occured
- the E horizon is consisting mainly of Silica
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What does a soil colour of yellow to redish suggest
- Fe3+ is present in the soil
- this occurs in well aerated soils
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What does a gray greenish blue soil mean
- Gray greenish blue is indicitive of a
- Fe2+ presence
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What environment does a grey greenish blue soil (Fe2+) occur in?
Poorly drained soils
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What does a white to gray soil colour represent
White to grey is the accumulation of salts
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What parent material would cause a white to gray soil colour
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Name from smallest to largest
Clay Sand Silt
- Clay 0.002 mm
- silt 0.002 - 0.05 mm
- Sand 0.05 - 2 mm
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What does a smaller size mean in realtion to chemical reactions
A smaller size of soil means a greater surface area on the soil meaning more pore spaces and water holding capacity along with increased surface area for chemical reactions meaning a greater rate of chemical reaction
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What five effects does a greater surface area due to smaller particles of soil have
- 1. Water as thin films greater surface area meaning greater chem rxns
- 2. Greater Gas retention
- 3. Faster rate of plant nutrient release
- 4. Greater attraction for charged minerals
- 5. microbe reactions
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Remerb what u know about sand silt and clay water hlding nutrient holding attraction to eachother size u already know all these things well enough to fill in his chart
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