Podcast
Questions and Answers
What does the Principle of Original Horizontality state?
What does the Principle of Original Horizontality state?
- Rock fragments within another rock are younger.
- Sedimentary layers are deposited in horizontal layers. (correct)
- Fossils appear in a recognizable order over time.
- The oldest layer is always on top.
Which type of unconformity involves older sedimentary layers being tilted or folded?
Which type of unconformity involves older sedimentary layers being tilted or folded?
- Disconformity
- Nonconformity
- Angular Unconformity (correct)
- Paraconformity
What does radiometric dating primarily measure?
What does radiometric dating primarily measure?
- The sequence of rock layers
- The decay of radioactive isotopes (correct)
- The position of fossils in layers
- The thickness of sedimentary rocks
In the Principle of Faunal Succession, what is the significance of fossil organisms?
In the Principle of Faunal Succession, what is the significance of fossil organisms?
Which method is suitable for dating very old rocks using radiometric principles?
Which method is suitable for dating very old rocks using radiometric principles?
What is a characteristic of a disconformity?
What is a characteristic of a disconformity?
What is a half-life in the context of radiometric dating?
What is a half-life in the context of radiometric dating?
Which principle suggests that a geological feature cutting through another must be younger?
Which principle suggests that a geological feature cutting through another must be younger?
Flashcards
Principle of Superposition
Principle of Superposition
In undisturbed sedimentary rock layers, the oldest is at the bottom.
Principle of Original Horizontality
Principle of Original Horizontality
Sedimentary layers are deposited horizontally; tilting happens later.
Principle of Cross-Cutting Relationships
Principle of Cross-Cutting Relationships
Features that cut through layers are younger than the layers they cut.
Principle of Inclusions
Principle of Inclusions
Signup and view all the flashcards
Disconformity
Disconformity
Signup and view all the flashcards
Nonconformity
Nonconformity
Signup and view all the flashcards
Half-Life
Half-Life
Signup and view all the flashcards
Carbon-14 Dating
Carbon-14 Dating
Signup and view all the flashcards
Study Notes
Relative Dating Principles
- Superposition: In undisturbed sedimentary rock layers, the oldest layer is at the bottom, and the youngest at the top.
- Original Horizontality: Sedimentary layers are originally deposited horizontally. Tilting or folding indicates later events.
- Cross-Cutting Relationships: A geological feature (fault, intrusion) that cuts across existing layers is younger than the layers it cuts through.
- Inclusions: Rock fragments (inclusions) within a rock are older than the rock they are included in.
- Faunal Succession: Fossil organisms appear and disappear in a specific, recognizable order, used to correlate rock layers across different locations.
Unconformities
- Disconformity: A gap in the rock record between parallel layers of sedimentary rock, often subtle due to erosion or non-deposition.
- Angular Unconformity: Older tilted or folded rock layers are eroded, and younger horizontal layers are deposited on top.
- Nonconformity: Sedimentary rocks rest on eroded igneous or metamorphic rocks, indicating a long period of erosion or missing time.
- Paraconformity: A type of disconformity where there are no visible signs of erosion but a period of missing time exists in the rock record.
Radiometric Dating
- Radiometric Dating: Measures radioactive isotope decay to determine absolute ages of rocks and minerals.
- Parent Isotope: The original radioactive isotope.
- Daughter Isotope: The stable product resulting from decay.
- Half-Life: The time it takes for half of a radioactive isotope to decay.
- Common Methods:
- Carbon-14 Dating: Used for organic materials up to ~50,000 years old.
- Uranium-Lead Dating: Used for very old rocks (millions to billions of years).
- Potassium-Argon Dating: Used for volcanic rocks (useful in archaeology and geology).
- Rubidium-Strontium Dating: Used for very old rocks & minerals.
- Complement to Relative Dating: Radiometric techniques provide absolute age data, complementing the relative age information from stratigraphy.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
