Tectonic Forces and Fold Classification

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Questions and Answers

What characterized the Hadean Era?

Stabilization of Earth's core and crust (correct)

Evolution of amphibians

Development of a breathable atmosphere

Formation of multicellular organisms

During which era did the atmosphere begin to contain oxygen?

Proterozoic Era (correct)

Hadean Era

Paleozoic Era

Archean Era

Which event was significant in the Paleozoic Era?

Invention of tools by reptiles

Emergence of mammals

Development of marine invertebrates

Formation of the supercontinent Pangaea (correct)

What was a key development during the Devonian period of the Paleozoic Era?

Inhalation of air by amphibians Signup and view all the answers

What type of atmosphere characterized the Archean Era?

Methane-rich atmosphere Signup and view all the answers

What type of fault is characterized by the upper block moving down relative to the lower block due to tensional forces?

Normal fault Signup and view all the answers

Which dating method identifies the exact numeric age of rocks using isotopes?

Radiometric dating Signup and view all the answers

What process transforms sediments into solid sedimentary rocks?

Lithification Signup and view all the answers

Which geological fault is caused by compressional forces, with the upper block moving over the lower block?

Thrust fault Signup and view all the answers

What principle states that new rock layers are formed on top of older layers?

Law of Superposition Signup and view all the answers

Which of the following is NOT a type of absolute dating?

Law of Superposition Signup and view all the answers

In geological terms, what is the correct order of time divisions from smallest to largest?

Age, Epoch, Period, Era, Eon Signup and view all the answers

What do fossils provide evidence of within Earth's geological history?

Past events and organism life Signup and view all the answers

What do compressional tectonic forces primarily result in?

Convergent plate boundaries Signup and view all the answers

Which type of force is characterized by rocks sliding past one another?

Shearing forces Signup and view all the answers

Which type of fold is described as an upward arch in the layers of rocks?

Anticline Signup and view all the answers

What results from a plane under compressional forces that can no longer hold the pressure?

Fault Signup and view all the answers

Which characteristic best describes a symmetrical fold?

Vertical axial plane and the same angle of fold limbs Signup and view all the answers

What type of faults are inclined fractures where the blocks have mostly shifted vertically?

Dip-slip faults Signup and view all the answers

Which type of fold is referred to as a 'downfold'?

Syncline Signup and view all the answers

What happens to fold limbs in a recumbent fold?

They lie horizontally Signup and view all the answers

Which major event marked the Mesozoic Era?

Breakup of major landmasses Signup and view all the answers

What significant impact did the ice ages have during the Cenozoic Era?

Contributed to the formation of vast geological features Signup and view all the answers

Which of the following is considered a natural hazard?

Volcanic eruptions Signup and view all the answers

What hazard is commonly associated with earthquakes occurring under the ocean?

Tsunamis Signup and view all the answers

Which organization is responsible for monitoring seismic activities in the Philippines?

PHIVOLCS Signup and view all the answers

Which of the following best describes ground shaking during an earthquake?

The vibration of the ground Signup and view all the answers

What effect does surface faulting have during an earthquake?

It causes displacement reaching the Earth's surface. Signup and view all the answers

Which type of hazard is caused by human activities?

Deforestation Signup and view all the answers

What is the primary activity involved in excavation within archaeology?

Removing soil to expose remains Signup and view all the answers

Which of the following human activities contributes to landslides?

Cutting trees Signup and view all the answers

What is one of the negative economic effects of landslides?

Cost to repair structures Signup and view all the answers

How many typhoons does the Philippines experience on average each year?

19 to 22 Signup and view all the answers

How is a tropical cyclone defined?

A storm with low atmospheric pressure Signup and view all the answers

What is PAGASA responsible for in relation to typhoons?

Naming and monitoring weather disturbances Signup and view all the answers

What temperature is necessary for the formation of tropical cyclones?

Greater than 26°C Signup and view all the answers

Which hydrometeorological hazard is NOT commonly associated with typhoons?

Seismic activity Signup and view all the answers

Which of the following accurately describes a landslide?

The down-slope movement of rock, debris, or earth due to gravity. Signup and view all the answers

What are the main types of movement associated with landslides?

Falls, slumps, slides, spreads, and flows. Signup and view all the answers

Which factor does NOT contribute to triggering a landslide?

High-speed winds. Signup and view all the answers

How does liquefaction affect buildings and infrastructure?

It causes soil to become unstable, risking collapse. Signup and view all the answers

What primarily influences the speed of tsunami waves?

The depth of the ocean where it travels. Signup and view all the answers

Which method is commonly recognized for human activities that accelerate landslides?

Mining operations using explosives. Signup and view all the answers

What is the result of insufficient stability in hill slopes?

Occurrence of landslides. Signup and view all the answers

Which statement about tsunamis is incorrect?

They can only damage coastal buildings. Signup and view all the answers

Study Notes

Types of Tectonic Forces

Compressional Forces: Forces pushing together on opposite sides of a plane. Deformation is possible without breaking. Results in convergent plate boundaries and folding. Folding creates wave-like deformations in layered rock.
Tensile Forces (or Extensional Forces): Forces pulling apart on opposite sides of a plane. Results in divergent plate boundaries and faulting.
Shearing Forces: Forces acting parallel to a plane, causing rocks to slide or smear past each other. Results in transform plate boundaries.

Folds

Folds are wavelike deformations in layered rock resulting from bending.
Anticline: An upward fold. Highest point called the anticlinal crest.
Syncline: A downward fold. Lowest point called the synclinal trough.
Fold limbs are layers between the anticlinal crest and synclinal trough.

Classification of Folds

Symmetrical (Simple): Same angle of fold limbs with a vertical axial plane.
Asymmetrical: Different angles between fold limbs and an inclined axial plane. One fold limb is steeper than the other.
Overturned: Fold limbs tilted beyond vertical dip; axial plane inclined so strata on one limb is overturned.
Recumbent: Fold limbs are horizontal due to over-compression and horizontal axial planes.

Faults

Faults are breaks in rock due to too much pressure.
Dip-slip Faults: Inclined fractures where blocks mostly shifted vertically.
- Normal Faults: Caused by tensional forces; the block above the fault has moved down relative to the block below.
- Reverse Faults: Caused by compressional forces; the block above the fault has moved up relative to the block below.
- Thrust Faults: One section of land slips over another at a low angle when land is compressed. Caused by compressional forces.
Strike-slip Faults: Blocks move mostly horizontally. Also known as "transform" or "lateral" faults, caused by shearing forces.

Stratified Rocks and Dating

Stratified rocks are layered rocks often containing fossils.
Fossils: Valuable for researching Earth's history.
Formation of Stratified Rocks: Lithification transforms sediments into solid sedimentary rocks through processes like accumulation, compaction, and cementation.
Relative Dating: Determining the order or arrangement of rocks from youngest to oldest using the Law of Superposition.
Absolute Dating: Identifying numeric age through radioactive dating. Uses the ratio of isotopes (parent and daughter isotopes). Examples include tree rings and radiometric dating.

Earth's History

Earth's history is divided into eons (largest unit), eras, periods, epochs, and ages.
Precambrian Eon: Hadean, Archean, and Proterozoic Eras - Early Earth history.
Phanerozoic Eon: Paleozoic, Mesozoic, and Cenozoic Eras – includes abundant life forms and recognizable geological features.

Hydrometeorological Phenomena and Hazards

Hazards: Events that cause negative impacts on humans and environment (e.g., earthquakes, volcanic eruptions, tsunamis, landslides).
Typhoons/Hurricanes/Cyclones: Rapidly rotating low-pressure systems forming over tropical oceans.
Landslides: Movement of soil, rocks, and debris down a slope due to insufficient stability (natural or human-induced).

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Description

Explore the different types of tectonic forces including compressional, tensile, and shearing forces that shape our planet's crust. Additionally, learn about folds, their classifications such as anticlines and synclines, and the characteristics of symmetrical and asymmetrical folds. This quiz tests your knowledge of these fundamental geological concepts.