Fossils, Dating Methods, and Reconstructing Past Environments

Flashcards about fossils, dating methods, and reconstructing past environments from a lecture transcript.

What is the main topic of the lecture?

Fossils, dating methods, and reconstructing past environments.

Who was Mary Anning?

An unsung hero of paleontology who made important discoveries but received little credit.

What were the reasons Mary Anning was an 'unsung hero'?

She was a woman, and she didn't have a lot of status.

What is 'deep time,' and who is credited with the concept?

The concept of the Earth's immense age, credited to James Hutton, with Charles Lyell expanding upon it.

What is uniformitarianism?

The idea that the kinds of environmental effects happening today have always been happening.

How did Carl Sagan help people understand the concept of deep time?

He arranged Earth's history into a theoretical year to help people understand the proportions of time.

Approximately how old is the Earth?

4,600,000,000 years old.

What is taphonomy?

The study of what an organism undergoes after death.

What is 'context' in taphonomy, and why is it important?

The position where the organism falls, and it's important because its position has information that can be lost if moved.

Why is fossilization considered rare?

Because it doesn't happen every time.

What is lithification?

When sentiment becomes stoned through the process of mineralization.

What are some different kinds of fossils?

Plants, human/animal remains, amber, asphalt (tar), and trace fossils.

What is Steno's law of superposition?

Layering. The idea that soil is constantly being laid down, and the remains at the bottom are older than those at the top.

What is fluorine dating useful for?

Site-specific dating because it depends on the amount of fluorine in the environment at that location.

What is chronometric dating?

Using radioactive decay to figure out how long it's been since something happened.

How does carbon-14 dating work?

By looking at how much carbon-14 becomes nitrogen-14 through radioactive decay and half-life.

What are some types of chronometric dating methods?

Radiocarbon dating, potassium-argon dating, argon-argon dating, and uranium dating.

How does luminescence dating work?

By heating up rock and measuring its luminescence to determine the last time it was heated to 500 degrees Fahrenheit.

What is dendrochronology?

Looking at tree rings to determine when a tree was cut down, especially useful for dating human habitation in the American Southwest.

Why are paleoenvironments important when talking about fossilization?

Critical because they are part of the context. Diet reconstruction, soil types, sediment chemistry, pollen reconstruction, etc.

What does soil identification tell us about paleoenvironments?

Whether there were grasslands or woodlands, based on the presence of C3 or C4 carbon.

What are C3 plants associated with?

Wetlands, wooded areas, and jungly areas.

What is stable isotype work used for?

Figuring out things like where someone or something drank their water.