Age range for dating calculation
Although this discovery revealed flaws in the previous methods of calculating the age of the Earth, it provided a new method: .Geologists discovered that radioactive materials decay into other elements at a very predictable rate.How do scientists know Earth is 4.54 billion years old?It’s actually difficult to tell from the surface of the planet alone, since plate tectonics constantly reshape its surface.Also, over time, the amounts of Pb-206 and Pb-207 will change because as these isotopes are end-products of uranium decay. The higher the uranium-to-lead ratio of a rock, the more the Pb-206/Pb-204 and Pb-207/Pb-204 values will change with time.Now, supposing that the source of the Solar system was also uniformly distributed with uranium isotopes, then you can draw a data line showing a lead-to-uranium plot and, from the slope of the line, the amount of time which has passed since the pool of matter became separated into individual objects can be computed.
Geologists set about exploring the Earth, seeking the oldest rock formations on the planet.
Older parts of the surface slide under newer plates to be recycled in the Earth’s core.
The oldest rocks ever found on Earth are 4.0 – 4.2 billion years old.
Small particles of dust collected together into larger and larger objects – pebbles, rocks, boulders, etc – until there were many planetoids in the Solar System.
These planetoids collided together and eventually enough came together to become Earth-sized.