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Ganderia or Gander Terrane (located near the town Gander, Newfoundland) is a terrane in the northern Appalachians which broke off the supercontinent Gondwana (Ma) together with Avalonia, Megumia, and Carolinia.
Between 640 and 455 Ma intermittent Island arc magmatism were separated by soft collisional events, first in the Late Ediacaran and Early Cambrian while Ganderia was part of Gondwana, and then in the Ordovician when Ganderia was an isolated microcontinent. The first early phase of arc magmatism occurred 625–605 Ma in the Brookville and New River terranes, but also in Anglesey. The next phase of arc magmatism accompanied by metamorphism occurred at the end of the Precambrian in Newfoundland, New Brunswick and on Cape Breton Island.
Ganderia probably separated from Gondwana near the Cambrian-Ordovician boundary when subduction ceased and a arc-Back-arc basin system developed along a clastic passive margin. The separation of Ganderia opened the northern Rheic Ocean. Ganderia and Carolinia were probably connected during the Late Ediacaran and, if so, were collectively separated from Avalonia during the Early Palaeozoic.
When Ganderia was finally accreted to Laurentia during the Late Ordovician and Silurian large scale magmatism accompanied its subduction. Its accretion to Laurentia during the Late Ordovician closed large parts of the Iapetus Ocean and the accretion of its trailing edge resulted in the Salinic orogeny (the closure of the Tetagouche–Exploits Valley back-arc basin). Avalonia was subsequently subducted beneath Ganderia during the Silurian and Devonian.
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