A banded iron formation in Dales Gorge, Western Australia
Siderian Period ( /saɪˈdɪəriən/; Greek: σίδηρος,
translit. sídēros, meaning "iron") is the first geologic period
Paleoproterozoic Era and lasted from 2500 Ma to 2300 Ma
(million years ago). Instead of being based on stratigraphy, these
dates are defined chronometrically.
The laying down of the banded iron formations (BIFs) peaked early in
this period. BIFs were formed as anaerobic algae produced waste oxygen
that combined with iron, forming magnetite (Fe3O4, an iron oxide).
This process cleared iron from the oceans, presumably turning greenish
seas clear. Eventually, without an oxygen sink in the oceans, the
process allowed the buildup of an oxygen-rich atmosphere. This event
is known as the oxygen catastrophe, which, according to some
geologists, triggered the Huronian glaciation.
For the time period from 2420 Ma to 2250 Ma, an alternative period
based on stratigraphy rather than chronometry, named the Oxygenian,
was suggested in the geological timescale review 2012 edited by
Gradstein et al., but as of February 2017[update], this has
not yet been officially adopted by the IUGS.
Siderian Period". GeoWhen Database. Retrieved May 24, 2015.
"The Siderian". Dinosaurfact.net. Retrieved May 24, 2015.
^ Paleoclimates: The First Two Billion Years - James F. Kasting &
Shuehi Ono, 2006 https://www.jstor.org/stable/20209693
Paleoproterozoic Snowball Earth: A climate disaster triggered by
the evolution of oxygenic photosynthesis - Kopp et al.
^ Gradstein, F.M. et al. (editors) (2012). The
Geologic Time Scale
2012. 1. Elsevier. pp. 361–365.
ISBN 978-0-44-459390-0. CS1 maint: Extra text: authors list
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