Absolute dating relative vs
They need however an absolute scale to state that the Paleozoic finished 250 million years ago (before present) and that the Cenozoic begun 66 million years BP.Absolute dating is the process of determining a specific date for an archaeological or palaeontological site or artifact. Sedimentary rocks form from soil and silt carried and deposited by moving water.Over time, the accumulated deposits compress and harden.In the West we chose to date every event from the birth of Christ (and got it wrong by six or seven years, but this is a different story). Other civilizations have their own zero starting point.
Potassium 40 decays into argon 40 at a predictable rate over enormous spans of time.Igneous rocks form from eruptions of lava or magma.Metamorphic rock is formed by great pressure far below the Earth's surface.Maybe they were both built before, or the pyramids before and the ESB after.Relative dating permits to evaluate which one of two events is the older and, with a certain accuracy, the time difference between the two.