Earth Science Seafloor and Dating Methods

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Questions and Answers

What method helped scientists pinpoint the exact age of Earth?

Chronological dating

Stratigraphic dating

Relative dating

Radiometric dating (correct)

What is one reason why magnetic patterns on the ocean floor were puzzling to scientists?

They suggested the ocean floor was static.

They revealed uniform age across the ocean floor.

They indicated consistent polarity throughout the ocean floor.

They showed alternating bands of normal and reversed polarity. (correct)

What occurs when temperature-pressure conditions exceed those required for metamorphism?

Rocks will become sediment.

Rocks will melt and form igneous rocks. (correct)

Rocks will undergo chemical alteration only.

Rocks will remain unchanged.

What does relative dating allow geologists to determine?

If a rock is older or younger than another rock. Signup and view all the answers

Which statement about the age pattern on the seafloor is not true?

The oldest seafloor is located near mid-ocean ridges. Signup and view all the answers

What characterizes regional metamorphism?

Metamorphic rocks formed from immense pressure and heat. Signup and view all the answers

Which statement regarding the geologic time scale is correct?

It is a record of the known history of rocks and fossils. Signup and view all the answers

How did scientists determine that rocks farther away from the mid-ocean ridge were older?

By determining the age of rock samples obtained by drilling. Signup and view all the answers

Which of the following best describes chemical weathering?

The process by which rocks are broken down by chemical means Signup and view all the answers

What happens at a divergent plate boundary?

Two tectonic plates pull away from one another, forming a rift valley Signup and view all the answers

Which statement does not accurately describe how a mountain can form?

A glacier moving down a valley deposits debris on Earth’s surface Signup and view all the answers

How do scientists use fossils to determine the relative ages of rock layers?

By comparing fossils in many different rock layers Signup and view all the answers

Which of the following is NOT considered a criterion for index fossils?

The fossil must have lived for only a long time Signup and view all the answers

What is the importance of dating in geology?

To estimate the absolute ages of specific rock layers Signup and view all the answers

What happens to the rock if it is exposed to tension stress?

Rocks will be pulled apart Signup and view all the answers

Which type of stress is caused by the collision of two tectonic plates?

Compressional stress Signup and view all the answers

What effect does magma's viscosity have on volcanic eruptions?

It affects how explosive the eruption will be Signup and view all the answers

Which of the following best describes how pressure affects the melting of rocks?

The higher the pressure, the higher the melting points Signup and view all the answers

Study Notes

Multiple Choice Review Questions - Earth Science

Seafloor before echo sounders: Scientists thought the seafloor was completely flat.
Seafloor age determination: Scientists discovered older rocks further from the mid-ocean ridge by drilling and examining rock samples.
Magnetic patterns on ocean floor: Alternating bands of normal and reversed polarity were puzzling.
Seafloor age pattern: Youngest seafloor is near mid-ocean ridges.
Rock dating technique: Radiometric dating uses the decay rate of radioactive isotopes to determine age.
Earth's age determination method: Absolute dating helps determine the exact age of Earth.
Relative rock age determination: Geologists use relative dating to determine if one rock is older or younger than another.
Igneous rock absolute age: Determining the ratio of decayed to undecayed radioactive isotopes in igneous rocks.
Regional Metamorphism: Rocks changing due to intense pressure and heat.
Metamorphism and melting: Exceeding metamorphic conditions results in rock melting to form igneous rock
Metamorphism description: Changes in a rock due to altered conditions
Foliation & Lineation: Pressure and recrystallization cause this in deformed rocks
Geologic Time Scale Order: Precambrian, Paleozoic, Mesozoic, Cenozoic
Geologic Time Scale: A record of rock and fossil history
Cenozoic Era: Not the period where gymnosperms replaced angiosperms.
Dinosaur Extinction: Possibly caused by climate change from an asteroid impact.
Weathering: The mechanical or chemical breakdown of rocks.
Physical weathering example: (Not) Plant growth in cracks
Chemical weathering description: Chemical breakdown of rocks.
Oxidation example: Rust breaking down rocks over time
Mountain Formation: Caused by tectonic plates pushing together.
Mountain formation NOT example: Glacial deposits
Divergent plate boundary: Two plates moving apart, creating rifts or ridges.
Tectonic Plate Movement: Driven by convection currents.
Fossil relative age determination: Fossils in different rock layers are compared.
Index fossil criteria: An index fossil lives for a short time and has wide distribution.
Index fossil use: Estimating absolute ages of rock layers.
Fossil formation: Organisms die and their remains are covered in sediment.
Relative rock age indicator: Position of layers compared to other layers.
Dating importance: (Not) Determining particles in fossils.
Relative dating and digging: Deeper you dig, the older the rocks.
Relative dating characteristic: Does not involve numerical dating
Sedimentary rock formation: Sand and gravel become rock from pressure.
Superposition: Youngest rocks are on top in undisturbed layers.
Rock layer formation: Erosion and weathering.
Continental slope: From oceanic to continental crust
Ocean basin embryonic stage: Rift valleys form.
Ocean crust meets continental: Ocean crust sinks.
Tension stress effect: Rocks pull apart.
Shear stress effect: Rock surfaces slip in opposite directions.
Mountain formation stress: Compressional stress.
Ava's clay bar stress: Compressional stress
Viscosity effect on volcanic eruption: Lower viscosity results in less explosive eruptions.
Rock melting factors: Temperature, pressure, and mineral composition.
Pressure effect on rock melting: High pressure increases melting point.
Magma formation conditions: Low pressure and high temperature.
Earth as a thermal engine: Internal heat from isotopes.
Internal heat buildup: Heat escape is slower than heat generation.
Early Earth heat generation: Collision of gas and dust masses.
Earth's internal heat source: Radioactive elements.

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Description

This quiz covers key concepts in Earth Science focused on seafloor exploration and rock dating techniques. Topics include seafloor age determination, magnetic patterns, and both absolute and relative dating methods used by geologists. Test your knowledge on the processes that shape our planet's geology.