Geologic time relative age dating totally on linedating

24-Sep-2020 08:37

For example, the lower Jurassic Series in chronostratigraphy corresponds to the early Jurassic Epoch in geochronology.The adjectives are capitalized when the subdivision is formally recognized, and lower case when not; thus "early Miocene" but "Early Jurassic." Evidence from radiometric dating indicates that Earth is about 4.54 billion years old.This clock representation shows some of the major units of geological time and definitive events of Earth history.The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga (billion years ago).Geologists study these fossils, and the rock strata in which they appear, to figure out how old they are compared to each other, or their relative age.Remember, relative age does not tell us the exact years that these organisms lived.Therefore, the second timeline shows an expanded view of the most recent eon.In a similar way, the most recent era is expanded in the third timeline, and the most recent period is expanded in the fourth timeline.

The three million year Quaternary period, the time of recognizable humans, is too small to be visible at this scale.Geologic units from the same time but different parts of the world often look different and contain different fossils, so the same time-span was historically given different names in different locales.