Etymology of Proterozoic geological period names

period when started root word meaning reason for name
Siderian 2500 Ma Greek sidēros iron ref. the banded iron formations
Rhyacian 2300 Ma Gk. rhyax lava flow much lava flowed
Orosirian 2050 Ma Gk. orosira mountain range much orogeny in this period's latter half
Statherian 1800 Ma Gk. statheros stable, firm continents became stable cratons
Calymmian 1600 Ma Gk. calymma cover platform covers developed or expanded
Ectasian 1400 Ma Gk. ectasis extension platform covers expanded
Stenian 1200 Ma Gk. stenos narrow much orogeny, which survives as narrow metamorphic belts
Tonian 1000 Ma Gk. tonas stretch The continental crust stretched as Rodinia broke up
Cryogenian 850 Ma cryogenic freezing-making In this period all the Earth froze over
Ediacaran 635 Ma Ediacara Hills place in Australia where the Ediacaran biota fossils were found

See also

Hadean eon
Cryptic Basin Groups Nectarian Lower Imbrian
Archean eon
Eoarchean Paleoarchean Mesoarchean Neoarchean
Proterozoic eon
Paleoproterozoic era Mesoproterozoic era Neoproterozoic era
Siderian Rhyacian Orosirian Statherian Calymmian Ectasian Stenian Tonian Cryogenian Ediacaran
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