This course covers systems of radioactive, radiogenic, and stable isotopes in the natural world. The first part of the course will focus on dating methods including U-Pb, K-Ar, Rb-Sr, uranium series disequilibrium, and 14C. The second part of the course will cover stable isotope systems, which can be used as paleoclimate proxies and as past and present environmental indicators. Primarily 18O, deuterium, and 13C will be covered, but we may touch on others. The course will involve lecture, discussion, and some analysis of student-collected samples.