Weathering, Mass Movement and Groundwater Flashcards
The earth’s crust is constantly undergoing geological changes caused by -
Internal forces
_______________build new mountain ranges
Orogenesis
What is denudation-
The process of wearing away the earth causes a general lowering and levelling out of the surface.
Phases of denudation-
4 phases-
- Weathering
- Erosion
- Transportation
- Deposition
Weathering—
The gradual disintegration of rocks by atmospheric or weather forces.
Erosion—
The active wearing away of the earth’s surface by moving agents like running water , wind , ice and waves.
Transportation—
The removal of the eroded debris to new positions.
Deposition—
The dumping of the debris in certain parts of the earth, wher it can accumulate to form new rocks.
Types of weathering-
- Chemical weathering
2. Physical or mechanical weathering
Consider the following statements-
- Chemical weathering is a fast process.
- Does chemical weathering weaken the surface of the rocks. explain
- Wrong, its a slow process.
- Chemical process require some amount of water and air to start the chemical reaction which is more than enough to dissolve certain constituents , thus loose crystals and weaken the surface.
What is regolith?
They are mineral remians of decomposed rocks.
The rain water absorbs organic acids from the soil and thus becomes a stronger weathering agent than pure rain water acting on bare rock. Is the statement true?
True
Three major chemical weathering process-
- Solution
- Oxidation
- Decomposition by organic rocks
- Solution is the most potent weathering process in which region?
- Is the density of joints or cracks in the rock is also crucial to speed the weathering?
- Do weathering often proceeds very rapidly in tropical countries with heavy rainfall and warm climate?
- Do climate affect the rate of weathering?
- Chemical weathering is fast where, at warm wet climate or dry climate?
- Limestone regions
- Yes
- Yes
- Yes
- Warm wet climate
Dry climate provide good conditions for-
Physical or mechanical weathering
What is oxidation?
Reaction of oxygen in air or water with minerals in the rock.
Does oxidation weaken the rocks?
Yes
Does bacteria help to speed up the weathering of the underlying rocks?
Yes bacteria produces acid which when dissolved in water speed up the weathering. These absorb chemical elements from the rocks as food and also produce organic acids.
In which type of weathering process frost-shattered peaks are formed ?
Physical or mechanical weathering due to frost action.
Mass movement is the movement of weathered materials down a slope due to _________?
Gravitational Force
what are soil creep?
This is a slow,gradual but more or less continuous movement of soil down hillslopes.
What is solifluction?
The soil acts like a liquid and a soil-flow or mud-flow occurs.
Landslides occur in ________?
What may loosens rocks and start off a landslide?
Steep slopes or mountainous areas.
Earthquakes or volcanic mountains.
________is particularly common where permeable debris or rock layers overlie impermeable strata such as clay.
Slumping
