Ganderia
terrane in the northern Appalachians which broke off the supercontinent Gondwana
Ganderia or Gander Terrane (located near the town Gander, Newfoundland) is a terrane in the northern Appalachians which broke off the supercontinent Gondwana c. 570 million years ago (Ma) together with Avalonia, Megumia, and Carolinia.
Extent
The microcontinent Avalonia broke off Gondwana in the Late Neoproterozoic together with a series of terranes that either formed its eastern coast or a separate block called Ganderia in front of it, if so separated from the Avalon Zone by the several hundred metres-wide Dover Fault. These terranes include the Early Palaeozoic siliciclastic rocks of the Gander Zone, the eastern passive margin of the Iapetus Ocean, now found in Newfoundland, New Brunswick, and New England, but they also include the contemporaneous or slightly older rocks of the Bras d'Or terrane in Cape Breton Island, the 550 Ma Upsalquitch gabbro, the Brookville and New River terranes in New Brunswick, and the Seven Hundred Acre Island in Maine. The Gander Zone also extends to the British Isles: Southeast Ireland, Anglesey, Isle of Man, and the Lake District. The western margin of Ganderia is the Red Indian Line of the Iapetus Suture.
Tectonic history
The basement beneath Ganderia is unexposed, but the rock of the Green Head Group in southern New Brunswick, the oldest known, contains the Precambrian stromatolite Archaeozoon acadiense, and the Seven Hundred Acre Island Formation in coastal Maine has been dated to c. 670–1230 Ma, similar in age to that of the Amazonian Craton.
Between 640 and 455 Ma intermittent 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.
Begin with the source’s own compact description: “Ganderia” is terrane in the northern Appalachians which broke off the supercontinent Gondwana. The dossier treats that line as a proposition to test through Ganderia, terrane and northern, not as a finished interpretation.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated May 18, 2026. The linked authority identifier is Q48816130. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1230.
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This entry incorporates text from “Ganderia” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.