EOSC 114 Lecture Notes - Lecture 25: Geologic Time Scale, Principle Of Faunal Succession, Superposition Principle
Document Summary
Biosphere: thin layer of life on surface of earth that interacts with hydrosphere, atmostphere, + lithosphere. Biosphere evolves over time as species evolve, go extinct the actors change. Superposition principle: oldest rock is the bottom layer, youngest rock at top. Original horizontality: sediment deposited in layers due to gravity. Cross cutting relationships: the cross-cutting layer is younger because the layers must be there first! Faunal succession: change in fossil species over time; can sort fossils in layers far apart because of evolution depending on type, can categorize into time period. Depending on what animal the fossil is of, it can separate rock layers into time categories. James ussher- said earth was 6000 from info in the bible. George cuvier-found mammoth fossil and determined it was extinct. Nicholas steno devised principle of superposition (top layer = youngest) for stratigraphy. William smith devised principle of faunal succession (uses fossils to determine different rock ages) for biostratigraphy.
