Editing Geologic time scale (section)

=== 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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PlotArea   = left:15 right:15 bottom:20 top:5
AlignBars   = early

Period      = from:-4500 till:0
TimeAxis    =  orientation:horizontal
ScaleMajor  = unit:year increment:500 start:-4500
ScaleMinor   = unit:year increment:100 start:-4500

Colors =
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  id:theiicol value:rgb(1,0.2,0.5)
  id:phyllocol  value:rgb(0.7,0.4,1)

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 align:center  textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5)

 text:Siderikan  from:-3500  till:0 color:sidericol
 text:Theiikian from:-4000 till:-3500  color:theiicol
 text:Phyllocian from:start till:-4000  color:phyllocol
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