ARCL 140 Lecture Notes - Lecture 12: Biostratigraphy, Taphonomy, Dendrochronology
Document Summary
Taphonomy - the study of how the burial site was created. The bone has been petrified/ turned to stone. Silica, lime, iron dissolved in water - organic materials replaced. The creation of fossils are very rare. More likely that harder tissue becomes fossils, not soft tissue. The study of the relationships between the different rock layers and the relationship they have with time. Rock layers are strata, the relationship with time is called context. Principles of stratigraphy - how it is formed, how it changed, what forces were behind it. Nicholas steno (1669) steno"s laws of stratigraphy. Principle of original horizontality - strata follow the earth"s gravitational forces, if there is vertical strata, most likely moved by tectonic movement. Principle of superimposition - the farther down, the older the sediment, the older the strata, youngest near the top. Principle of cross cutting relationship - if a strata is cross cutting, it is the youngest layer until it is covered.