Editing Cambrian (section)

=== Siberia ===
Siberia began the Cambrian close to western Gondwana and north of Baltica. It drifted northwestwards to close to the equator as the Ægir Ocean opened between it and Baltica.<ref name="Torsvik-2017" /><ref name="Wong Hearing-2021" /> Much of the continent was covered by shallow seas with extensive [[Archaeocyatha|archaeocyathan reefs]]. The then northern third of the continent (present day south; Siberia has rotated 180° since the Cambrian) adjacent to its convergent margin was mountainous.<ref name="Torsvik-2017" />

From the Late Neoproterozoic to the Ordovician, a series of island arcs accreted to Siberia's then northeastern margin, accompanied by extensive arc and [[Back-arc region|back-arc]] volcanism. These now form the [[Altai-Sayan region|Altai-Sayan]] terranes.<ref name="Torsvik-2017" /><ref name="Domeier-2018" /> Some models show a convergent plate margin extending from Greater Avalonia, through the Timanide margin of Baltica, forming the Kipchak island arc offshore of southeastern Siberia and curving round to become part of the Altai-Sayan convergent margin.<ref name="Keppie-2024"/>

Along the then western margin, Late Neoproterozoic to early Cambrian rifting was followed by the development of a passive margin.<ref name="Domeier-2018" />

To the then north, Siberia was separated from the Central Mongolian terrane by the narrow and slowly opening [[Mongol-Okhotsk Ocean]]. The Central Mongolian terrane's northern margin with the Panthalassa was convergent, whilst its southern margin facing the Mongol-Okhotsk Ocean was passive.<ref name="Torsvik-2017" />