ENV234H1 Lecture Notes - Lecture 2: Gneiss, Pleistocene, Paleozoic
Document Summary
Lecture 2: geological concepts and geology of ontario. Half-life: the amount of time necessary to reduce the number of parent atoms by 50% from the original number: https://portal. utoronto. ca/bbcswebdav/pid-5473634-dt-content-rid- Radioactive dating of the earth: daughter products form from parents at characteristic rates of decay (half-lives, ratio of daughter products to remaining parent material tells how much time has elapsed, determines absolute age of organic materials. Important isotopes (different isotopes used for different purposes) Sedimentary: e. g. , carbonates and shales, ordovician shallow sub-tropical marine sediments. Metamorphic: e. g. , gneiss, oldest rock in the world. Rock cycle: through varying heats, pressures, erosion and weathering, rocks change types: http://www. classzone. com/books/earth_science/terc/content/investigations/es060. Layer i: precambriam eon: precambrian igneous and metamorphic rock, precambrian canadian shield rocks, over 40km thick, 3-0. 8 billion years. Layer ii: ordovician period: ordovician marine sediments, mainly sedimentary rocks, less than 500 metres thick, paleozoic rocks, 543-350 million years old.
