Answer:
Radioactive.
Explanation:
A geologic column can be defined as a collection of rock layers that are typically grouped based on their relative ages in a descending order i.e from oldest to the youngest.
Generally, the layers of the rock that are found in various parts of the world are known to be different because they all comprises of distinct Earth's geological history.
In Science, absolute dating can be defined as a process used to accurately determine the age of a rock or fossil by measuring the decay of isotopes associated with the rock or within the fossils.
Generally, absolute dating relies on radioactive elements such as uranium, polonium, thorium, francium, radon, etc., which are mainly unstable elements that release energy as they break down through fission.
In conclusion, these informations when properly obtained can be used to determine the age of any historical monument or material such as earth, rocks, animals, plants, etc., because the parent material decays into a stable daughter elements at a constant decay rate.
