EAS100 Lecture Notes - Lecture 8: Radiocarbon Dating, Unconformity, Exponential Decay

• School: University of Alberta
• Department: Earth and Atmospheric Sciences
• Course: EAS100
• Professor: Korhan

Document Summary

Eas 100 - lecture #8 - time & earth history. Radioactive isotopes allow the ages of earth materials to be determined. All matter is composed of about 90 naturally occurring elements. Atoms are the smallest individual particles of an element. Different forms of an element that have different numbers of neutrons. Each particle has the same chance of decaying on a given day. Statistically, for a larger number of atoms, a fixed proportion will undergo decay in a. Measured by half-life (time for half the atoms of an isotope to decay) Mineral grains must have formed at the same time as the rock. To date sedimentary rocks we must use other methods. Only a few, mainly igneous rocks contain material that can be dated isotopically. For sedimentary strata, we use methods to find relative age. Layers of sediment are originally deposited horizontally due to gravity. Index fossils (known age) can be compared for the age of the rock.