The key difference between carbon dating and uranium dating is that carbon dating uses radioactive isotopes of carbon, whereas uranium dating uses uranium, which is a radioactive chemical element.
Carbon dating and uranium dating are two important methods of determining the age of different organic materials. We call them isotopic dating methods. The oldest method among them is Uranium-Lead dating method. Although it is a very risky method, if we do it very carefully, the results are highly accurate.
CONTENTS
1. Overview and Key Difference
2. What is Carbon Dating
3. What is Uranium Dating
4. Side by Side Comparison – Carbon Dating vs Uranium Dating in Tabular Form
5. Summary
What is Carbon Dating?
Carbon dating or radiocarbon dating is a method of determining the age of organic material using radioactive isotopes of the chemical element carbon. The radioactive isotope we use for this method is carbon-14. We call it radiocarbon.
The basic theory behind this dating method is the fact that carbon-14 constantly forms in the atmosphere via the interaction between cosmic rays and atmospheric nitrogen. Newly created carbon-14 reacts with atmospheric oxygen and forms carbon dioxide, which has radiocarbon atoms. Therefore, we call it radioactive carbon dioxide. Thereafter, this radioactive carbon dioxide is incorporated into plants for photosynthesis. By consuming these plants, animals also get radiocarbon into their bodies.
Figure 01: Decay of Carbon-14
Eventually, when these animals or plants die, the intake of radiocarbon stops. Then, the existing amount of carbon-14 inside the dead plant or animal matter starts to decrease due to the radioactive decay of radiocarbon. Therefore, by measuring the amount of carbon-14 that is present in a sample of organic material, we can determine the time at which that plant or animal died. Less amount of carbon-14 is present in the sample if the sample is old.
We can determine the exact age of the sample because we know the half-life of carbon-14. The half-life of a chemical element is the period of time after which half of a given sample will have decayed. For carbon-14, the half-life is about 5730 years. This technique is very important in forensic investigations, in determining the age of fossils, etc.
What is Uranium Dating?
Uranium dating is the oldest method of isotopic dating in which we can determine the age of organic materials using the radioactive chemical element Uranium. There are three different types of this technique: Uranium-Uranium method, Uranium-Thorium method and Uranium-Lead method. Among them, Uranium-lead method is the oldest method. But, it gives the most accurate results though it has a high risk.
Figure 02: Uranium Dating in a Simple Diagram
In Uranium-Uranium method, we use two different radioactive isotopes of Uranium. These are U-234 and U-238. U-238 undergoes alpha and beta decay and forms Pb-206, which is a stable isotope. In Uranium-Thorium dating method, we use U-234 and Th-230 radioisotopes. The uranium-lead method includes the decay of U-238 into Pb-206 or Pb-207 isotopes.
What is the Difference Between Carbon Dating and Uranium Dating?
There are different isotopic dating methods. Carbon dating and uranium dating are two such methods. Among them, the uranium dating method is the oldest method. The key difference between carbon dating and uranium dating is that carbon dating uses radioactive isotopes of carbon w,hereas uranium dating uses uranium, which is a radioactive chemical element.
Below infographic summarizes the difference between carbon dating and uranium dating.
Summary – Carbon Dating vs Uranium Dating
There are different isotopic dating methods. Carbon dating and uranium dating are two such methods. Among them, the uranium dating method is the oldest method. The key difference between carbon dating and uranium dating is that carbon dating uses radioactive isotopes of carbon, whereas uranium dating uses uranium which is a radioactive chemical element.
Reference:
1. Alden, Andrew. “Uranium-Lead Dating.” ThoughtCo, Feb. 10, 2019, Available here.
Image Courtesy:
1. “Carbon-Dating-Flashcards” By Zappys Technology Solutions (CC BY 2.0) via Flickr
2. “UraniumDating” By KelvinW 344 – Own work (Public Domain) via Commons Wikimedia