Isotopes in Fossil Dating

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What do fossil records and sedimentary rocks contain?

Foscop6Ss (correct)

Fossilized plants

Dinosaur fossils

Radioactive isotopes

Why do heavy isotopes change with temperature?

They react with oxygen

They are radioactive

They are affected by temperature (correct)

They are always heavy

What is the result of continental drift?

Pangea breaks apart (correct)

Mountain ranges form

Volcanic eruptions occur

Sea levels rise

What happens to sea levels when the climate cools?

They fall Signup and view all the answers

What is the process called when continents collide?

Continental collision Signup and view all the answers

What happens to the width of a ridge as it cools?

It decreases Signup and view all the answers

What is the result of the movement of tectonic plates?

All of the above Signup and view all the answers

What would happen to sea levels if all ice caps were to melt?

They would increase Signup and view all the answers

What was the approximate sea level at the end of the Time of the Dinosaurs compared to today?

125 m higher Signup and view all the answers

What was a contributing factor to the warmer climates during the time of the dinosaurs?

Faster rates of sea floor spreading Signup and view all the answers

What was an effect of the flooding of coastal areas during the time of the dinosaurs?

A moderating effect on climate Signup and view all the answers

What occurs when continents collide?

Larger ocean basins are created Signup and view all the answers

What happened to the climate towards the end of the Time of the Dinosaurs?

It deteriorated due to decreased volcanism and a drop in sea level Signup and view all the answers

Why did warm water take up more space during the time of the dinosaurs?

Because it expanded when heated Signup and view all the answers

What is the primary reason for the difference in width between fast-spreading and slow-spreading mid-ocean ridges?

Rate of cooling Signup and view all the answers

What was a result of the decrease in sea level towards the end of the Time of the Dinosaurs?

Increased seasonality and temperature gradient Signup and view all the answers

What would be the approximate change in sea level if all ice sheets were to melt?

70 m Signup and view all the answers

What is the process that reduces the effect of adding a large volume of water to the sea floor?

Isostasy Signup and view all the answers

What occurs when rocks cool completely at mid-ocean ridges?

They level out at a depth of 5500 m Signup and view all the answers

What is the estimated rise in sea level due to thermal expansion and contraction of water?

1 m/ 1°C Signup and view all the answers

Why is it unclear whether the rates of sea-floor spreading were faster more than 100 Mya?

Because part of the record has been destroyed through subduction Signup and view all the answers

What would be the approximate sea level if all ice sheets melted and the climate was similar to that of the Time of the Dinosaurs?

77 m higher than today Signup and view all the answers

Study Notes

Isotopes and Fossil Records

Fossil records contain FscopSs, which are familiar to animals using isotopes to build drips and shallower rates to change with temperature.
This helps to reconstruct past climate changes by analyzing the isotopes' ratings.
Temple's width during time was several wommer, and the still vertab rates went down from place to place.

Climate Change and Sea Levels

Carbon dioxide levels won't stay the same and will change the climate, which affects sea levels.
During the time of the dinosaurs, the sea level was higher due to high temperatures.
Even a 1% change in sea levels would contribute to the sea levels rising, which affected the climate.

Continental Movement and Volcanic Activity

Pangea, a supercontinent, broke apart due to volcanic activity, which led to the formation of new oceans.
This volcanic activity caused an increase in global temperatures, contributing to climate change.
The breaking apart of Pangea also led to the formation of different continents, which in turn affected sea levels.

Mid-Ocean Ridges and Sea Floor Spreading

Mid-ocean ridges are areas where new oceanic crust is being created due to volcanic activity.
This process leads to the expansion of the ocean floor and the movement of continents.
The ocean floor spreading is a slow process that has been occurring over millions of years.

Sea Level Changes and Ice Ages

Changes in sea levels are due to the movement of continents and the changing volume of water in the oceans.
During ice ages, sea levels were lower due to the ice caps locking away water, and when the ice melted, sea levels rose.
Changes in sea levels have been occurring over millions of years, affecting the Earth's climate.

Continental Collisions and Sea Level

Continent-continent collisions pile continents on top of each other, creating larger ocean basins and causing sea level to drop.
During the time of Pangaea, sea level would have dropped due to continental collisions.
Splitting the continents apart would have kept sea level higher than it is today.

Mid-Ocean Ridges and Sea Level

Mid-ocean ridges at divergent boundaries are tall due to heating from below, causing them to expand.
The crests of the ridges occur 2500 m below sea level and slope down away from the crest as the rock cools.
The rocks cool completely after ~60 Myr and level out at a depth of ~5500 m below sea level.
Fast-spreading ridges are wider than slow-spreading ridges due to the rate of cooling.
When rates of spreading are higher, more water is displaced by the ridges than when rates are slower.

Climatic Factors and Sea Level

If all the ice sheets melted today, sea level would rise almost 70 m.
Ice sheets were not present during the Time of the Dinosaurs, therefore sea level was almost 70 m higher.
Warm water occupies more space than cool water, resulting in a 7m higher sea level than today (roughly 1 m/ 1°C).

Other Adjustments to Sea Level

Isostasy reduces the effect of adding a large volume of water by ~30%.
Variations in the shape/gradient of the world's continental margins also affect sea level.

Cretaceous Sea Levels

Current estimates indicate that towards the end of the Time of the Dinosaurs, sea levels were ~125 m higher than today.
However, the reasons are not fully understood.

Summary

Climates were warmer during the time of the dinosaurs.
Fast spreading resulted in more volcanism.
Giant, gassy dinosaurs existed.
Sea levels were higher due to warmer climates, melting of ice sheets, and thermal expansion of water.
Faster rates of spreading ripped continents apart, reducing the size of ocean basins.
Mid-ocean ridges took up more space.
Flooding of coastal areas had a moderating effect on climate.
Decreased volcanism on the sea floor and a drop in sea level caused increased seasonality and a greater temperature gradient between the equator and poles.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn how isotopes are used in fossil dating to determine climate changes and temperatures. Understand how animals use isotopes to build their shells and how these isotopes can tell us about the past.