Relative age dating of rocks fish in the pond dating service
Say for example that a volcanic dike, or a fault, cuts across several sedimentary layers, or maybe through another volcanic rock type.
Pretty obvious that the dike came after the rocks it cuts through, right?
This follows due to the fact that sedimentary rock is produced from the gradual accumulation of sediment on the surface.
Therefore newer sediment is continually deposited on top of previously deposited or older sediment.
In order for any material to be included within in the rock it must have been present at the time the rock was lithified.
For example, in order to get a pebble inside an igneous rock it must be incorporated when the igneous rock is still molten-- such as when lava flows over the surface.
Since, all sedimentary rock is formed through the gradual accumulation of sediment at the surface over time, and since the principle of superposition tells us that newer sediment is deposited on top of older sediment, the same must also be true for fossils contained within the sediment.
With absolute age dating, you get a real age in actual years.
It’s based either on fossils which are recognized to represent a particular interval of time, or on radioactive decay of specific isotopes. Based on the Rule of Superposition, certain organisms clearly lived before others, during certain geologic times.
After all, a dinosaur wouldn’t be caught dead next to a trilobite.
The narrower a range of time that an animal lived, the better it is as an index of a specific time.