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Questions and Answers
The ______ cycle is affected by the hydrologic cycle as well as the tectonic cycle.
The ______ cycle is affected by the hydrologic cycle as well as the tectonic cycle.
rock
______ is the chemical and physical breakdown of rock exposed to air, moisture, and living organisms.
______ is the chemical and physical breakdown of rock exposed to air, moisture, and living organisms.
Weathering
The breakdown of rock into solid fragments by physical processes is called ______ weathering.
The breakdown of rock into solid fragments by physical processes is called ______ weathering.
mechanical
The decomposition of rocks and minerals by chemical and biochemical reactions is known as ______ weathering.
The decomposition of rocks and minerals by chemical and biochemical reactions is known as ______ weathering.
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Loose debris overlying bedrock is called ______, formed by the weathering of the rocks immediately below it.
Loose debris overlying bedrock is called ______, formed by the weathering of the rocks immediately below it.
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Minerals formed deep within the Earth's interior are not ______ at the surface.
Minerals formed deep within the Earth's interior are not ______ at the surface.
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The ______ reaction series helps understand the stability of minerals.
The ______ reaction series helps understand the stability of minerals.
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The most important agent in chemical weathering is ______.
The most important agent in chemical weathering is ______.
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Quartz is highly ______ under surface conditions.
Quartz is highly ______ under surface conditions.
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Feldspars can be altered to form ______ minerals.
Feldspars can be altered to form ______ minerals.
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The process of dissolving minerals in water is called ______.
The process of dissolving minerals in water is called ______.
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Salt weathering can be caused by the ______ of salt crystals within rock.
Salt weathering can be caused by the ______ of salt crystals within rock.
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The chemical formula for the reaction of ______ with oxygen is 4FeSiO3 + O2 = 2(Fe2O3) + 4(SiO2)
The chemical formula for the reaction of ______ with oxygen is 4FeSiO3 + O2 = 2(Fe2O3) + 4(SiO2)
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The presence of small amounts of ______ results in a red stain on weathered debris and rock.
The presence of small amounts of ______ results in a red stain on weathered debris and rock.
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Weathering of the mineral ______ not only produces iron oxide but also releases sulfur into solution, forming sulfuric acid.
Weathering of the mineral ______ not only produces iron oxide but also releases sulfur into solution, forming sulfuric acid.
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The process of ______, often associated with mining operations, is caused by the weathering of pyrite.
The process of ______, often associated with mining operations, is caused by the weathering of pyrite.
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The ______ is one of the most important factors influencing weathering.
The ______ is one of the most important factors influencing weathering.
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The ______ can significantly influence weathering rates.
The ______ can significantly influence weathering rates.
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Weathering occurs more rapidly on ______ slopes.
Weathering occurs more rapidly on ______ slopes.
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______ can expose new rock surfaces to weathering.
______ can expose new rock surfaces to weathering.
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Microorganisms play a significant role in ______, particularly through the formation of algal mats.
Microorganisms play a significant role in ______, particularly through the formation of algal mats.
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Rock that has been fragmented, transported, and deposited is called ______.
Rock that has been fragmented, transported, and deposited is called ______.
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The process of breaking down rocks at the Earth's surface is called ______.
The process of breaking down rocks at the Earth's surface is called ______.
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Tiny mineral particles with properties similar to clay minerals are called ______.
Tiny mineral particles with properties similar to clay minerals are called ______.
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The partially decayed organic matter in soil is called ______.
The partially decayed organic matter in soil is called ______.
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A sediment made of relatively coarse mineral grains is called ______.
A sediment made of relatively coarse mineral grains is called ______.
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______ is a mixture of minerals, organic matter, and other components.
______ is a mixture of minerals, organic matter, and other components.
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A soil profile is a sequence of soil ______ from the surface down to bedrock.
A soil profile is a sequence of soil ______ from the surface down to bedrock.
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The ______ of a soil profile is influenced by factors such as climate and rock type.
The ______ of a soil profile is influenced by factors such as climate and rock type.
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The loose debris produced by weathering is called ______.
The loose debris produced by weathering is called ______.
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Flashcards
Weathering
Weathering
The chemical and physical breakdown of rock exposed to air, moisture, and living organisms.
Mechanical Weathering
Mechanical Weathering
The breakdown of rock into solid fragments by physical processes without altering the chemical composition.
Chemical Weathering
Chemical Weathering
The decomposition of rocks and minerals through chemical and biochemical reactions.
Regolith
Regolith
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Rock Cycle
Rock Cycle
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Dissolution
Dissolution
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Ion Exchange
Ion Exchange
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Oxidation
Oxidation
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Hydrolysis
Hydrolysis
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Feldspar to Clay
Feldspar to Clay
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Salt Weathering
Salt Weathering
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Acid Mine Drainage
Acid Mine Drainage
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Factors Affecting Weathering
Factors Affecting Weathering
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Rock Composition
Rock Composition
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Tectonic Setting
Tectonic Setting
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Topography
Topography
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Biological Activity
Biological Activity
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Climate Influence
Climate Influence
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Rock Structure
Rock Structure
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Vegetation's Role
Vegetation's Role
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Rock Hazard Analysis
Rock Hazard Analysis
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Weathering Effects
Weathering Effects
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Sediment
Sediment
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Clay
Clay
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Humus
Humus
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Soil Composition
Soil Composition
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Soil Horizon
Soil Horizon
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Soil Profile
Soil Profile
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Regolith and Soil
Regolith and Soil
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Study Notes
Chapter 7 Weathering - Hoodoos
- Hoodoos experience weathering at a rate of approximately 1 meter every 100 years.
Geological Assistant Job Posting
- Application deadline is Tuesday, January 21, 2025, 11:59 PM EST.
- Position is a student position.
- Organization: Various Ministries
- Division: Various Divisions and Branches
- Location: Kenora, Red Lake, Sault Ste Marie, South Porcupine, Sudbury, Swastika, Thunder Bay, Tweed
- Language: English
- Job Type: 13 Temporary positions of varying contract length over the summer
- Job Code: Student 2 - Student Level 2
- Salary: $18.05-$18.05 per hour* (*Indicates the salary listed as per the OPSEU Collective Agreement.)
- Job ID: 223776
- Application link: https://www.gojobs.gov.on.ca/
Annual Scholarships (2025)
- Scholarship amount: $3,000
- Deadline to apply: February 6, 2025
- Eligible Students: Students enrolled in Mining-Related Post-Secondary programs connected to Northwestern Ontario.
- Application method: Visit wimnwo.com for application or submit via email to [email protected]
Chapter 7 Weathering - Recap
- Rock Cycle: the set of processes that form, change, and break down rocks.
- Two main types of weathering: mechanical and chemical.
- Factors influencing weathering: Tectonic setting, rock composition, rock structure, topography, amount of vegetation and biological activity, and climate.
Chapter 7 Weathering - The Rock Cycle
- The rock cycle is affected by the hydrologic cycle as well as the tectonic cycle and is powered by energy from the sun.
- Processes involved include igneous rock formation, erosion, deposition, sedimentation, and metamorphosis of both igneous and sedimentary rocks.
Plate Tectonics and Weathering
- Heat stored in the Earth drives plate tectonics contributing to mountain belt formation.
- High relief in these areas leads to extensive erosion, turning igneous and metamorphic rocks into sediment, which blankets the surrounding area.
- Over 70% of loose debris on Earth's surface originates from mountain belts due to high relief promoting erosion.
- Rivers transport this sediment to the oceans, where it's incorporated into mountain chains (either scraped off or melted).
Weathering: The First Step in the Rock Cycle
- Weathering is the chemical and physical breakdown of rocks exposed to air, moisture, and living organisms (chemical and physical weathering).
- Erosion is the transport of rock particles by gravity or a fluid (air, water, or ice).
Mechanical Weathering
- Mechanical weathering involves breaking rock into smaller fragments without changing its chemical composition.
- Processes include: the breakdown of rock into solid fragments, root wedging, glacial grinding, heating of the rock, pressure release, and abrasion in streams.
Water, Air, and Microorganisms in Weathering
- Water, air, and microorganisms penetrate cracks and react with rock, shaping it into loose debris.
- This process gradually transforms rock, increasing surface area for further reactions and weathering.
Regolith and Soil
- Regolith is loose debris overlying bedrock, formed from weathering below.
- Soil is the topmost layer of regolith capable of supporting rooted plants.
Joint Formation
- Rock masses can experience jointing from overlying/surrounding pressure or tectonic squeezing.
- Granite bodies show varying levels of jointing.
- Joints influence weathering rates- more joints = faster weathering.
Physical (Mechanical) Weathering - Causes
- Root and frost wedging
- Glacial grinding
- Heating of the rock
- Pressure release
- Abrasion in streams
Tree Roots and Weathering
- Tree roots pry apart rocks, contributing to their weathering.
Freeze/Thaw Weathering (Frost Wedging)
- Repeated freezing and thawing of water within rock cracks expands the water, widening cracks and breaking the rock apart.
Chapter 7 Weathering - Other Processes
- Glacial processes: Glaciers flowing over land can scour rock surfaces, breaking off and transporting loose material.
- Sheet joints: This type of weathering occurs mostly in massive intrusive igneous rocks (like granite) due to pressure release. The expansion and contraction of the rock due to temperature changes can also cause layers of the rock to crack off.
- Spheroidal weathering: This occurs when heating and cooling cycles cause thin layers of rock to crack, often resulting in spherical shapes on the rock surface.
- Moving water (rivers and waves): These are significant erosional forces actively shaping landforms.
- Chemical weathering: This process occurs due to the instability of minerals formed deep within the Earth when subjected to surface conditions.
- Dissolution: A reaction between minerals and acidic or alkaline water, altering the mineral's stability. Rainwater is slightly acidic due to dissolved CO2, which forms carbonic acid. This carbonic acid can dissolve calcite in limestone, which forms large cavities in the rocks.
- Ion exchange: Acidic water containing hydrogen ions enters feldspar crystals, causing potassium ions to dissolve.
- Oxidation: Iron-rich minerals in the presence of oxygen and water can undergo hydrolysis to form iron oxide, which is an insoluble mineral precipitate. This contributes to discoloration and the eventual weathering of the rock.
- Acid mine drainage: The weathering of pyrite releases sulfur into solution, which reacts with water to produce sulfuric acid. This leads to acid mine drainage in many mining areas.
Factors Affecting Weathering
- Tectonic setting: Different tectonic settings can result in different rates and types of weathering.
- Rock composition: Different minerals weather at varying rates. Calcite weathers quickly through dissolution, while quartz is highly resistant to weathering.
- Rock structure: Distribution of joints impacts the rate of weathering. Closely spaced joints result in faster weathering.
- Topography: Weathering proceeds faster on steep slopes because they expose underlying rock to weathering factors.
- Vegetation and biological activity: Vegetation can contribute to both mechanical and chemical weathering through processes like root wedging and increased water retention in the soil. Removing vegetation can increase soil loss.
- Climate: Chemical weathering prevails in warm, wet tropical climates, occurring quickly and extensively at great depths. Mechanical weathering is more prevalent in cold, dry regions. Hot and dry climates typically result in slower weathering of both types.
Products of Weathering
- Sediment: Rock fragments that have been transported and deposited.
- Clay: Tiny mineral particles with characteristic physical properties similar to clay minerals. They are hydrous aluminosilicate minerals.
- Humus: Partially decayed organic matter in soil
- Sand: Soil particles characterized by their relatively coarse mineral grains.
Soil Profiles and Horizons
- Soil horizons: are zones or layers within a soil profile. Each horizon has different physical, chemical, and biological characteristics.
- Soil profiles: Soil horizons form a sequence from the surface down to underlying bedrock.
- Pedalfers, spodosols, and mollisols: Typical types of soil found in Ontario.
Soil Erosion
- On-surface erosion: includes particle displacement (raindrop erosion), channeling water flow through the ground and gullies enlarging.
- Underground erosion: includes piping - the hydraulic removal of soil particles by subsurface flow.
- Wind erosion: Mechanisms include suspension (dust storms), saltation (jumping), and rolling/creep.
Erosion Control
- Agricultural Practices: Contour farming, strip cropping, terracing, conservation tilling.
- Contour Farming: Orienting crop rows alongside elevation contours to disrupt water flow.
- Strip Cropping: Alternating strips of erosion-inhibiting crops (like grasses) with more erodible row crops, to slow runoff.
- Terracing: Building embankments and terraces on slopes; especially in rice paddy agriculture.
- Conservation Tilling: Techniques to reduce soil disturbance and exposure during cropping.
Additional Information
- Job application procedures and deadlines may vary.
- There is a video on soil erosion which can provide further information.
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Description
This quiz explores the concepts of weathering processes and their relationship with the hydrologic and tectonic cycles. Test your knowledge on physical and chemical weathering, mineral stability, and the effects of environmental factors on rock breakdown.
