Which type of rock is most reliable for radiometric dating
The 11th-century Persian geologist Avicenna (Ibn Sina, died 1037) and the 13th-century Dominicanbishop Albertus Magnus (died 1280) extended Aristotle's explanation into a theory of a petrifying fluid.
Avicenna also first proposed one of the principles underlying geologic time scales, the law of superposition of strata, while discussing the origins of mountains in The Book of Healing (1027).
Older time spans, which predate the reliable fossil record (before the Proterozoic eon), are defined by their absolute age.
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.
The geologic time scale (GTS) is a system of chronological dating that relates geological strata (stratigraphy) to time, and is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships of events that have occurred during Earth's history.
The tables of geologic time spans, presented here, agree with the nomenclature, dates and standard color codes set forth by the International Commission on Stratigraphy (ICS).
The three million year Quaternary period, the time of recognizable humans, is too small to be visible at this scale.The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon.Therefore, the second timeline shows an expanded view of the most recent eon.Dominantly fluid planets, such as the gas giants, do not preserve their history in a comparable manner.Apart from the Late Heavy Bombardment, events on other planets probably had little direct influence on the Earth, and events on Earth had correspondingly little effect on those planets.