Geologic Time Principles and Evolutionary Milestones Quiz

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What are the three main principles that underlie the interpretation of geologic time, as devised by Nicholas Steno?

The principle of superposition, the principle of horizontality, the principle of original lateral continuity

What is the study of layered rock known as?

Stratigraphy

Who proposed that all rocks came from the ocean environment?

Abraham Gottlob Werner

What is the process of determining the age of a rock or fossil based on its decay rate of radioactive isotopes called?

Absolute Age Dating Signup and view all the answers

What term is used for fossils that are used to define and identify geologic periods?

Index fossils Signup and view all the answers

What type of organism are trilobites, often used as index fossils?

Trilobites Signup and view all the answers

What does 'relative age' mean in terms of dating rocks?

The age of one object compared to the age of another, not the exact age of an object. Signup and view all the answers

What is the process called when all six of the original stratigraphic principles are applied to determine the age of a rock?

Age dating. Signup and view all the answers

According to the principles of original horizontality and superposition, where is the oldest rock usually found?

On the bottom. Signup and view all the answers

How do scientists use species, composition, or texture to determine the age of rocks?

By correlating strata by rock unit type or fossil type. Signup and view all the answers

What is the main goal of Darwin's 'Origin of Species' work?

To convince the world that evolution had occurred and organisms had changed over geologic time. Signup and view all the answers

What is the significance of trilobites as index fossils in relative age dating?

Trilobites are useful for correlating rock layers because they existed for a short period of time but were widespread. Signup and view all the answers

What are the three types of unconformities that help determine relative ages of rock layers?

<ol> <li>Angular 2. Disconformity 3. Nonconformity</li> </ol> Signup and view all the answers

Explain how angular unconformity is formed in relative age dating.

Horizontal beds are uplifted and tilted or eroded, followed by the deposition of new horizontal beds. Signup and view all the answers

What does a nonconformity in relative age dating indicate?

Sediment is deposited on top of eroded volcanic or metamorphic rock, suggesting a long passage of time. Signup and view all the answers

How can relative ages be determined using Lyell’s principle of cross-cutting relationships?

The layer that cuts through other layers is the youngest, as it must have been preceded by the layers it cuts through. Signup and view all the answers

What is biostratigraphy, and how is it used in relative age dating?

Biostratigraphy is the correlation of stratigraphic units based on fossil content. It utilizes index fossils for recognition of chronostratigraphic units. Signup and view all the answers

Why are trilobites considered useful as index fossils?

Trilobites are useful index fossils due to their wide distribution, rapid evolution, and short geologic range. Signup and view all the answers