The International Commission on Stratigraphy revises the timescale annually.
These updated versions are available in multiple languages and are free to download: International Chronostratigraphic Chart Everyone knows geologists love rocks, but when we talk about dating them, we’re not talking about going to a fancy restaurant and ordering a nice pasta dish with our favorite chunk of granite.
Our understanding of the shape and pattern of the history of life depends on the accuracy of fossils and dating methods.
Some critics, particularly religious fundamentalists, argue that neither fossils nor dating can be trusted, and that their interpretations are better.
There are two main ways to determine the age of rocks: relative and absolute dating.Geoscientists are a unique group of scientists for several reasons, but mostly because we work with modern environments as well as interpret ancient environments in the rock record.Therefore, it is of the utmost importance that we as scientists understand how old the rocks are that we are working with, so that we can calculate rates, ages, and determine when geologic events happened.New discoveries have filled in the gaps, and shown us in unimaginable detail the shape of the great ‘tree of life’.Darwin and his contemporaries could never have imagined the improvements in resolution of stratigraphy that have come since 1859, nor guessed what fossils were to be found in the southern continents, nor predicted the huge increase in the number of amateur and professional paleontologists worldwide.In a way this field, called geochronology, is some of the purest detective work earth scientists do.