GEO 1111 Lecture Notes - Lecture 7: Cambrian Explosion, Love Wave, Seismic Wave

• School: University of Ottawa
• Department: Geology
• Course: GEO 1111
• Professor: Donald Cummings

Document Summary

Geo - lec 7 partial melting : melting a rock with different minerals, not all minerals melt at the same time partial melting of mantle (ultramafic) : produces oceanic crust (mafic) Radioactive parent isotopes decay to stable daughter isotopes with a characteristic half-life (time it takes for half of the parent atoms to decay) Diffusion of isotopes will no longer be possible in and out of the crystal, the ratio of parent to daughter isotopes will be fixed & the mineral"s radiometric clock will start. Short lived radioactive isotope (half life : 5730 years) Differ in number of neutrons in nucleus, therefore different atomic weight, but same size of atom. Co2 gets incorporated into living animals and plants, when organism dies, radiometric clock starts of the isotope. Measure beta emissions from co2 in a shielded. Help infer how fast events in the various spheres occur over multitude of time scales. C-14 helps to understand events, such as colonization of polynesia.