Radiometric dating age ranges

04 Nov

Clearly, Sedimentary Rocks A were deposited and deformed before the Volcanic Dyke intruded them.These were then eroded and Sedimentary Rocks B were deposited.When ‘parent’ uranium-238 decays, for example, it produces subatomic particles, energy and ‘daughter’ lead-206.Isotopes are important to geologists because each radioactive element decays at a constant rate, which is unique to that element.The Wheeler Formation has been previously dated to approximately 507 million year old, so we know the trilobite is also about 507 million years old.But, how can we determine how old a rock formation is, if it hasn’t previously been dated?

Index fossils are fossils that are known to only occur within a very specific age range.From the mapped field relationships, it is a simple matter to work out a geological cross-section and the relative timing of the geologic events.His geological cross-section may look something like Figure Tas Walker A geologist works out the relative age of a rock by carefully studying where the rock is found in the field.The field relationships, as they are called, are of primary importance and all radiometric dates are evaluated against them.