EAS100 Lecture Notes - Lecture 3: Cenozoic, Acasta Gneiss, Exoskeleton

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

Document Summary

Nucleus (p and n) surrounded by an electron cloud. Time for half of the parent atoms of an isotope to decay into its daughter. Rate of decay can also be measured by decay constant. Number of atoms at time t is related to starting number of atoms n0 by. Half life or decay constant of the isotope. Final amount of parent or daughter isotope in the sample. Mineral grains must have formed at the same time as the rock. Few rocks contain materials that can be dated isotopically. In an undisturbed succession, higher rocks are younger. Correlation was used to develop a geological time scale. Subsequently numerical ages were added using isotopic methods. Ka = kilo-annum (thousand years before present) Ma = mega-annum (million years before present) Ga giga-annum (billion years before present) Cross-cutting relationships also show relative ages of features. Strata have same orientation above and below. Birth of our solar system (~4. 6 ga)