Quiz 1 - Weathering Flashcards
It is the process of breakdown of rocks at the Earth’s surface, by the action of water, ice, acids, salts, plants, animals, gravity and changing temperatures.
Weathering
Three types of weathering
- Physical Weathering
- Chemical Weathering
- Biological Weathering
It is caused by the effects of changing temperature on rocks, causing the rock to break apart. The process is sometimes assisted by water.
Physical Weathering
It is caused by rain water reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts. These reactions occur particularly when the water is slightly acidic.
Chemical Weathering
It occurs when rocks are weakened by different biological agents like plants and animals. When plant roots grow through rocks, it creates fracture and cracks that result eventually to rock breakage.
Biological Weathering
It is a geological process in which earthen materials are worn away and transported by natural forces such as wind or water
Erosion
Types of Erosion
- Physical Erosion
- Chemical Erosion
- Water Erosion
Sources of Heat in the Planet
- Primordial Heat
- Radiogenic Heat
The Internal heat energy accumulated by dissipation in a planet during its first few million years of evolution. This is called accretional energy.
Primordial Heat
It is the thermal energy released as a result of spontaneous nuclear disintegration of natural radioactive elements inside the planet;
Uranium, Thorium, and Potassium.
Radiogenic Heat
Composition of Magma
Silicates, Gases, Metal Oxides
It is a complex mixture of molten rock, crystals, and dissolved gases found beneath Earth’s surface.
Magma
The most abundant group of minerals in magma, composed mainly of silicon and oxygen. The primary silicate minerals in magma include: Quartz, Feldspar, Mica, Olivine, and Pyroxene
Silicates
Dissolved gases in magma include: Water vapor, Carbon dioxide, Sulfur dioxide, Hydrogen sulfide, Nitrogen, and Chlorine
Gases
These include oxides of elements like iron, magnesium, aluminum, calcium, potassium, and sodium. These oxides influence the density, viscosity, and color of the magma
Metal Oxides
Magma is often classified based on its silica content into three major types:
- Basaltic Magma
- Andesitic Magma
- Rhyolitic Magma
Types of Magma Formation
- Decompression Melting
- Heat Transfer
- Flux Melting
Involves the upward movement of earth’s mostly-solid mantle.
Decompression Melting
This happens at convergent boundaries, where tectonic plates are crashing together melting the surrounding rocks into magma.
Heat Transfer
Occurs when water or other volatile components are added to rock. These compounds cause the rock to melt at lower temperature.
Flux Melting
It is the process of rock transformation due to changes in temperature, pressure, and chemical environment, occurring tens of kilometers below the surface without melting the rock.
Metamorphism
Types of Metamorphism
- Contact Metamorphism
- Regional Metamorphism
- Cataclastic Metamorphism
- Hydrothermal Metamorphism
- Burial Metamorphism
- Shock Metamorphism (Impact Metamorphism)
This happens when rocks are heated due to contact
monteatrone because of this, its rock minerals and texture changes.
Contact Metamorphism
The zone of contact of the rocks and magma is called
Contact Aureole
Unlike contact metamorphism, ______ metamorphism happens mainly because of pressure occurring in a broad range of area.
Regional Metamorphism
This type of metamorphism is not very common, and the main cause of this is the direct pressure applied to a specific zone.
Cataclastic Metamorhpism
It happens because of contact of rock to a high-temperature fluid or heated seawater.
Hydrothermal Metamorphism
It occurs when the sedimentary rocks that undergone diagenesis is buried even deeper with temperature of 300 degrees-Celsius.
Burial Metamorphism
It happens specifically when two bodies collide to each other. A great example of this is when an asteroid hit Earth
Shock Metamorphism (Impact Metamorphism)
Types of Physical Weathering
- Abrasion
- Freeze-Thaw
- Exfoliation
It occurs when rocks surface is frequently exposed to water, wind and gravity.
Abrasion
It occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart. It occurs in mountainous regions like the Alps or Snowdonia.
Freeze-Thaw
It can happen as cracks develop parallel to the land surface as a consequence of the reduction in pressure during uplift and erosion. It occurs typically in upland areas where there are exposures of uniform coarsely crystalline igneous rocks.
Exfoliation
Types of Chemical Weathering
- Carbonation
- Hydrolysis
- Hydration
- Oxidation
carbon dioxide in the air dissolves in rainwater and becomes weakly acidic. This weak “carbonic acid” can dissolve limestone as it seeps into cracks and cavities. Over many years, solution of the rock can form spectacular cave systems.
Carbonation
The breakdown of rock by acidic water to produce clay and soluble salts. Hydrolysis takes place when acid rain reacts with rock-forming minerals such as feldspar to produce clay and salts that are removed in solution.
Hydrolysis
A type of chemical weathering where water reacts chemically with the rocks, modifying its chemical structure. Example: H2O (water) is added to CaSO4 (calcium sulfate) to create CaSO4 + 2H2O (calcium sulfate dihydrate). It changes from anhydrite to gypsum.
Hydration
The breakdown of rock by oxygen and water, often giving iron- rich rocks a rusty-colored weathered surface
Oxidation
Types of Biological Weathering
- Biological Weathering by Physical Means
- Biological Weathering by Chemical Compounds
Burrowing animals like shrews, moles and earthworms create holes on the ground by excavation and move the rock fragments to the surface. These fragments become more exposed to other environmental factors that can further enhance their weathering.
Biological Weathering by Physical Means
Some plants and animals also produced acidic substances that react with the rock and cause its slow disintegration.
Biological Weathering by Chemical Compounds
