Top Qs
Timeline
Chat
Perspective

Siderian

First period of the Paleoproterozoic Era From Wikipedia, the free encyclopedia

Siderian
Remove ads

The Siderian Period ( /sˈdɪəri.ən, sɪ-/; Ancient Greek: σίδηρος, romanized: sídēros, meaning "iron") is the first geologic period in the Paleoproterozoic Era and lasted from 2500 Ma to 2300 Ma. Instead of being based on stratigraphy, these dates are defined chronometrically.

Quick Facts Chronology, Proposed redefinition(s) ...

The deposition of banded iron formations peaked early in this period. These iron-rich formations were formed as anaerobic cyanobacteria produced waste oxygen that combined with iron, forming magnetite (Fe3O4, an iron oxide). This process removed iron from the Earth's oceans, presumably turning greenish seas clear. Eventually, with no remaining iron in the oceans to serve as an oxygen sink, the process allowed the buildup of an oxygen-rich atmosphere. This second, follow-on event is known as the oxygen catastrophe, which some geologists believe triggered the Huronian glaciation.[2][3]

Since the time period from 2,420 Ma to 2,250 Ma is well-defined by the lower edge of iron-deposition layers, an alternative period named the Oxygenian, based on stratigraphy instead of chronometry, was suggested in 2012 in a geological timescale review.[4]

Remove ads

References

Loading related searches...

Wikiwand - on

Seamless Wikipedia browsing. On steroids.

Remove ads