Editing Geologic time scale (section)

== Non-Earth based geologic time scales ==
{{Main|Lunar geologic timescale|Martian geologic timescale|Geology of Venus}}Some other [[Planet#Solar System|planets]] and [[Natural satellite|satellites]] in the [[Solar System]] have sufficiently rigid structures to have preserved records of their own histories, for example, [[Geology of Venus|Venus]], [[Geology of Mars|Mars]] and the Earth's [[Moon]]. Dominantly fluid planets, such as the [[giant planet]]s, do not comparably preserve their history. 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. Construction of a time scale that links the planets is, therefore, of only limited relevance to the Earth's time scale, except in a Solar System context. The existence, timing, and terrestrial effects of the Late Heavy Bombardment are still a matter of debate.{{efn|Not enough is known about extra-solar planets for worthwhile speculation.|group=note}}

=== Lunar (selenological) time scale ===
The [[Geology of the Moon|geologic history]] of Earth's Moon has been divided into a time scale based on [[Geomorphology|geomorphological]] markers, namely [[impact crater]]ing, [[volcanism]], and [[erosion]]. This process of dividing the Moon's history in this manner means that the time scale boundaries do not imply fundamental changes in geological processes, unlike Earth's geologic time scale. Five geologic systems/periods ([[Pre-Nectarian]], [[Nectarian]], [[Imbrian]], [[Eratosthenian]], [[Copernican period|Copernican]]), with the Imbrian divided into two series/epochs (Early and Late) were defined in the latest Lunar geologic time scale.<ref name="Wilhelms_1987">{{Cite book |last=Wilhelms |first=Don E. |title=The geologic history of the Moon |series=Professional Paper |publisher=United States Geological Survey |year=1987 |doi=10.3133/pp1348}}</ref> The Moon is unique in the Solar System in that it is the only other body from which humans have rock samples with a known geological context.
{{Timeline Lunar Geological Timescale}}

=== Martian geologic time scale ===
The [[geological history of Mars]] has been divided into two alternate time scales. The first time scale for Mars was developed by studying the impact crater densities on the Martian surface. Through this method four periods have been defined, the Pre-Noachian (~4,500–4,100 Ma), Noachian (~4,100–3,700 Ma), Hesperian (~3,700–3,000 Ma), and Amazonian (~3,000 Ma to present).<ref name="Tanaka_1986">{{Cite journal |last=Tanaka |first=Kenneth L. |date=1986 |title=The stratigraphy of Mars |url=http://doi.wiley.com/10.1029/JB091iB13p0E139 |journal=Journal of Geophysical Research |language=en |volume=91 |issue=B13 |pages=E139 |doi=10.1029/JB091iB13p0E139 |bibcode=1986JGR....91E.139T |issn=0148-0227}}</ref><ref name="Carr_2010">{{Cite journal |last1=Carr |first1=Michael H. |last2=Head |first2=James W. |date=2010-06-01 |title=Geologic history of Mars |url=https://www.sciencedirect.com/science/article/pii/S0012821X09003847 |journal=Earth and Planetary Science Letters |series=Mars Express after 6 Years in Orbit: Mars Geology from Three-Dimensional Mapping by the High Resolution Stereo Camera (HRSC) Experiment |language=en |volume=294 |issue=3 |pages=185–203 |doi=10.1016/j.epsl.2009.06.042 |bibcode=2010E&PSL.294..185C |issn=0012-821X}}</ref>
{{Mars timescale}}
A second time scale based on mineral alteration observed by the OMEGA [[spectrometer]] on board the [[Mars Express]]. Using this method, three periods were defined, the Phyllocian (~4,500–4,000 Ma), Theiikian (~4,000–3,500 Ma), and Siderikian (~3,500 Ma to present).<ref name="Bibring_2006">{{Cite journal |last1=Bibring |first1=Jean-Pierre |last2=Langevin |first2=Yves |last3=Mustard |first3=John F. |last4=Poulet |first4=François |last5=Arvidson |first5=Raymond |last6=Gendrin |first6=Aline |last7=Gondet |first7=Brigitte |last8=Mangold |first8=Nicolas |last9=Pinet |first9=P. |last10=Forget |first10=F. |last11=Berthé |first11=Michel |date=2006-04-21 |title=Global Mineralogical and Aqueous Mars History Derived from OMEGA/Mars Express Data |url=https://www.science.org/doi/10.1126/science.1122659 |journal=Science |language=en |volume=312 |issue=5772 |pages=400–404 |doi=10.1126/science.1122659 |pmid=16627738 |bibcode=2006Sci...312..400B |s2cid=13968348 |issn=0036-8075}}</ref>
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Period      = from:-4500 till:0
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 text:Theiikian from:-4000 till:-3500  color:theiicol
 text:Phyllocian from:start till:-4000  color:phyllocol
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