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3. GEOLOGICAL FRAMEWORK
Fig. 28.
Paleozoic paleogeography showing the distribution of terranes in the peri-Gondwanan realm and the main stages
of the assembly of Pangea. This model interpreted the Upper Units as a far-traveled terrane drifted from Gondwana and
finally accreted to the Southern margin of Laurussia. The Rheic Ocean opened in Late Cambrian-Early Ordovician times
and widened during drifting to the North of Avalonia and the Upper Units of NW Iberia. (Gómez Barreiro
et al.,
2007)