Carbon 14 dating works
But the most accurate forms of absolute age dating are radiometric methods. Sedimentary rocks in particular are notoriously radioactive-free zones.
This method works because some unstable (radioactive) isotopes of some elements decay at a known rate into daughter products. Half-life simply means the amount of time it takes for half of a remaining particular isotope to decay to a daughter product. Good discussion from the US Geological Survey: geochronolgists just measure the ratio of the remaining parent atom to the amount of daughter and voila, they know how long the molecule has been hanging out decaying. So to date those, geologists look for layers like volcanic ash that might be sandwiched between the sedimentary layers, and that tend to have radioactive elements.
That’s because zircon is super tough – it resists weathering. Each radioactive isotope works best for particular applications.
The half-life of carbon 14, for example, is 5,730 years.
On the other hand, the half-life of the isotope potassium 40 as it decays to argon is 1.26 billion years.
So carbon 14 is used to date materials that aren’t that old geologically, say in the tens of thousands of years, while potassium-argon dating can be used to determine the ages of much older materials, in the millions and billions year range.
Yet, you’ve heard the news: Earth is 4.6 billion years old. That corn cob found in an ancient Native American fire pit is 1,000 years old. Geologic age dating—assigning an age to materials—is an entire discipline of its own.The checkbook is in hand cocked and ready to besmirch every last dollar in your savings account, and all that’s left to do is negotiate with the shop so you at least have a little bit of cash left to buy some inner tubes.But before your visions of grandeur run rampant and your checkbook becomes more hollow than Landis’ Maillot Jaune, are you sure carbon is the right frame material for your needs?You’ve drooled over your own teammates’ high-dollar race rig that has more carbon fiber on it than the International Space Station.You’ve done all your research, have test-ridden all of the latest, high dollar, carbon fiber machines, and you’ve picked your winner.