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Questions and Answers
What is the primary heat source responsible for earthquakes and volcanic activity on Earth?
What is the primary heat source responsible for earthquakes and volcanic activity on Earth?
Which process is NOT involved in the mechanical or physical weathering of rocks?
Which process is NOT involved in the mechanical or physical weathering of rocks?
What initiates the formation of igneous rocks?
What initiates the formation of igneous rocks?
Which of the following statements about igneous rocks is incorrect?
Which of the following statements about igneous rocks is incorrect?
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Which type of weathering involves the breakdown of rocks without changing their chemical composition?
Which type of weathering involves the breakdown of rocks without changing their chemical composition?
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What term describes the internal heat energy accumulated during the early evolution of the planet?
What term describes the internal heat energy accumulated during the early evolution of the planet?
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Which of the following is a key function of erosion in the geological processes?
Which of the following is a key function of erosion in the geological processes?
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What are the three main layers of the Earth?
What are the three main layers of the Earth?
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What is the silica content percentage that classifies a rock as ultramafic?
What is the silica content percentage that classifies a rock as ultramafic?
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Which type of igneous rock is characterized by a high viscosity magma before forming?
Which type of igneous rock is characterized by a high viscosity magma before forming?
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Which mineral is primarily associated with mafic igneous rocks?
Which mineral is primarily associated with mafic igneous rocks?
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What color is commonly associated with intermediate igneous rocks?
What color is commonly associated with intermediate igneous rocks?
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Which igneous rock example is representative of the ultramafic classification?
Which igneous rock example is representative of the ultramafic classification?
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What is the density characteristic of felsic igneous rocks?
What is the density characteristic of felsic igneous rocks?
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Which type of igneous rock contains the highest silica content?
Which type of igneous rock contains the highest silica content?
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What primary minerals are found in felsic igneous rocks?
What primary minerals are found in felsic igneous rocks?
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What process describes the breakdown of rocks without a change in their chemical composition?
What process describes the breakdown of rocks without a change in their chemical composition?
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Which factor contributes to mechanical weathering through the freezing and thawing of water in rock fractures?
Which factor contributes to mechanical weathering through the freezing and thawing of water in rock fractures?
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Which of the following is an example of chemical weathering?
Which of the following is an example of chemical weathering?
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What role do burrowing animals play in the weathering process?
What role do burrowing animals play in the weathering process?
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How does temperature affect mechanical weathering?
How does temperature affect mechanical weathering?
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What is the primary mechanism by which oxidation contributes to weathering?
What is the primary mechanism by which oxidation contributes to weathering?
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What is an effect of human activities on physical weathering?
What is an effect of human activities on physical weathering?
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Which process involves minerals reacting with water to form clay minerals?
Which process involves minerals reacting with water to form clay minerals?
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What percentage of the world's active and dormant volcanoes are found in the Ring of Fire?
What percentage of the world's active and dormant volcanoes are found in the Ring of Fire?
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Which of the following best describes a hazard?
Which of the following best describes a hazard?
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Which province is ranked first for the highest risk of hazards in the Philippines?
Which province is ranked first for the highest risk of hazards in the Philippines?
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Which statement is true about the hazards faced by the Philippines?
Which statement is true about the hazards faced by the Philippines?
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Which of the following is classified as an anthropogenic hazard?
Which of the following is classified as an anthropogenic hazard?
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What is the purpose of a hazard map?
What is the purpose of a hazard map?
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Which province ranks second due to the number of active and dangerous volcanoes?
Which province ranks second due to the number of active and dangerous volcanoes?
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What are geological processes primarily responsible for?
What are geological processes primarily responsible for?
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What primarily causes pyroclastic flows to occur?
What primarily causes pyroclastic flows to occur?
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What are lahars commonly formed from?
What are lahars commonly formed from?
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What is a characteristic feature of lava domes?
What is a characteristic feature of lava domes?
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Which natural disaster frequently affects the Philippines due to its geographical location?
Which natural disaster frequently affects the Philippines due to its geographical location?
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What distinguishes floods from other natural disasters?
What distinguishes floods from other natural disasters?
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What was a consequence of the Taal Volcano eruption in January 2020?
What was a consequence of the Taal Volcano eruption in January 2020?
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What is the largest component of gases released during a volcanic eruption?
What is the largest component of gases released during a volcanic eruption?
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How does the Philippines' location affect its geological hazards?
How does the Philippines' location affect its geological hazards?
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What characterizes phaneritic texture in rocks?
What characterizes phaneritic texture in rocks?
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Which principle states that younger sedimentary rock layers are deposited on top of older layers?
Which principle states that younger sedimentary rock layers are deposited on top of older layers?
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What does the principle of crosscutting relationships imply?
What does the principle of crosscutting relationships imply?
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Which texture is characterized by rocks having visible pits from gas escape?
Which texture is characterized by rocks having visible pits from gas escape?
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What does the term 'absolute age' refer to?
What does the term 'absolute age' refer to?
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Which principle explains that layers of sediment extend continuously unless interrupted by erosion?
Which principle explains that layers of sediment extend continuously unless interrupted by erosion?
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Which of the following textures indicates that mineral grains in the rock are too small to see with the unaided eye?
Which of the following textures indicates that mineral grains in the rock are too small to see with the unaided eye?
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What is the role of radioactive decay in determining absolute age?
What is the role of radioactive decay in determining absolute age?
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Study Notes
Exogenic Processes
- Exogenic processes are geological processes that occur on or near the Earth's surface, driven by external forces like water, wind, and ice. These processes are a part of the rock cycle.
Mechanical Weathering
- Mechanical weathering breaks down rocks into smaller pieces without changing their chemical composition.
- Factors affecting mechanical weathering include:
- Organic activity (e.g., plant roots)
- Human activities (e.g., digging, quarrying)
- Burrowing animals (e.g., rats, rabbits)
- Temperature changes (e.g., frost wedging)
- Abrasion (e.g., rocks rubbing against each other)
- Pressure changes (e.g., tectonic forces, uplift and erosion)
Chemical Weathering
- Chemical weathering alters the chemical composition of rocks through chemical reactions.
- Chemical reactions cause changes in the minerals of rocks.
- Dissolution: Minerals dissolve in water (e.g., Halite, Calcite).
- Hydrolysis: Minerals react with water, creating new minerals, often clay minerals (e.g., amphibole, pyroxene).
- Oxidation: Minerals react with oxygen, often causing the mineral to decompose (e.g., rust).
Weathering
- Weathering is the breakdown of rocks into smaller fragments and particles.
Erosion
- Erosion is the removal and transportation of weathered materials from one location to another.
- The agents of erosion are mainly water, wind, glaciers.
Mass Wasting
- Mass wasting refers to the downslope movement of sediments under the influence of gravity.
- Examples include:
- Falls
- Slides
- Avalanches
- Flows
Deposition
- Deposition is the process where eroded materials settle down in a new location.
Earth's Internal Heat
- The Earth's internal heat is generated by two main sources:
- Primordial Heat: leftover energy from the Earth's formation (kinetic energy from colliding particles)
- Radiogenic Heat: decay of radioactive elements (Uranium, Thorium, Potassium). -The Earth's core also contains molten iron and nickel.
Structure of the Earth
- The Earth has three main layers:
- Crust (solid rock)
- Mantle (liquid rock)
- Core (liquid outer and solid inner core, also composed of iron and nickel).
Relative Age
- Relative age refers to the age of rocks or geologic features compared to others and not an exact age.
- Geologists use observational methods to determine the relative age.
- Original horizontality principle: Sediments deposited horizontally. Tilted rocks were tilted after formation.
- Superposition principle: Younger layers are on top of older layers in a sequence of rock layers.
- Cross-cutting relationships: A feature that cuts across older rocks is younger than the rocks it cuts through
- Faunal succession: Different species lived at different times; fossils are used to date rocks
- Lateral continuity: Sediments originally continuous and only separated by valleys or erosion.
Absolute Age
- Absolute age refers to the exact age of a rock or fossil.
- Scientists use radioactive dating, which measures the decay rate of radioactive isotopes.
- Half-life: The time it takes for half of the radioactive atoms to decay.
Geologic Time Scale
- A standard timeline used to describe the age of rocks, fossils, and Earth's history.
- Divided into eons (largest unit), eras, periods, and epochs (smallest unit).
- Key events, like mass extinctions, define divisions.
- Phanerozoic Eon is characterized by visible life, divided into the Paleozoic, Mesozoic, and Cenozoic Eras.
- Precambrian Eon: Hadean, Archaean, and Proterozoic Eons.
Volcanic Hazards:
- Tephra: Volcanic fragments (ash, lapilli, blocks, bombs).
- Pyroclastic flows: Fast-moving flows of hot gas, ash, and volcanic rock.
- Lahars: Mudflows from volcanic ash and water.
- Lava flows: Molten rock flowing down a slope.
- Lava domes: Mound of viscous lava.
- Poisonous gases: Released during eruptions.
Earthquake Hazards:
- Ground shaking: Vibration of the ground.
- Surface faulting: Displacements along faults.
- Landslides and liquefaction: Ground failure.
- Tsunamis: Large waves generated by underwater earthquakes.
Geology
- The study of the Earth and its history. Includes studying materials forming the Earth, features, and structures. Processes acting on the Earth, including history of life on Earth.
Geological Processes and Hazards
- Geologic processes are naturally occurring events affecting Earth's surface.
- Geologic hazards are processes leading to significant damage, loss of life/property.
- Examples: earthquakes, volcanic eruptions, landslides, floods, tsunamis, and droughts
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