Relative dating principle of original horizontality Sekschat without regestered
the discovery of radioactivity that gave to the geologists a “clock” which helped them to define it.
The determination of absolute (radiometric) age of a rock is based on the radioactive decay of isotopes.
Only certain types of fossils are useful for correlation.
To be a good index fossil, the species should: Using index fossils, geologists were able to correlate across Europe, and then to other continents.
Time in geological terms has been described in two different ways: relative time and absolute time.
Relative time was determined long before absolute time.The age of a rock is determined by stratigraphy, a branch in geology which studies the chronology of events and changes, along with the development of organisms, which have determined the development of the Earth from when it became an independent spatial body until today.The age, or the chronology of geological creations and events is determined using relative and absolute age.Radioactive elements emit α and β particles, as well as γ rays, thus causing their mass to reduce over time, shifting eventually to stabile isotopes.The final stabile product (isotope) can be compared in quantity to the original radioactive element.