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TitreTaconian orogeny and the accretion of the Dashwoods block: a peri-Laurentian microcontinent in the Iapetus Ocean
AuteurWaldron, J W F; van Staal, C R
SourceGeology v. 29, no. 9, 2001 p. 811-814, https://doi.org/10.1130/0091-7613(2001)029<0811:toatao>2.0.co;2
Année2001
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 2000283
ÉditeurGeological Society of America
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1130/0091-7613(2001)029<0811:toatao>2.0.co;2
Mediapapier; en ligne; numérique
Formatspdf
ProvinceTerre-Neuve-et-Labrador
SNRC11O; 11P; 12A; 12B; 12G; 12H; 12I; 12P; 2E; 22L; 22M
Lat/Long OENS -60.0000 -54.0000 52.0000 47.0000
SujetsLaurentien; croûte continentale; décrochement horizontal; déformation; métamorphisme; marges continentales, atlantique; marges plaques; schistes; carbonates; Orogenèse Taconienne; Océan Iapetus; Zone d'Humber ; Sous-Zone de Dashwoods ; Supergroupe de Fleur de Lys ; Bloc de Dashwoods ; stratigraphie; tectonique; Protérozoïque; Cambrien; Ordovicien; Mésozoïque
Illustrationssketch maps; block diagrams; cross-sections
Résumé(disponible en anglais seulement)
The stratigraphy of the external Humber zone of the western Newfoundland Appalachians records protracted Neoproterozoic-Early Cambrian rifting, followed by development of a passive margin that persisted until late Early Ordovician (Arenigian) time (ca. 475 Ma). However, adjacent metamorphic rocks, derived from the Laurentian margin and preserved in the Dashwoods subzone, were deformed, overthrust by ophiolites, and intruded by arc plutons by 488 Ma. The adjacent Notre Dame subzone also records isotopic evidence of interaction with the margin by 488 Ma. We propose that a microcontinent (Dashwoods microcontinent) was rifted from Laurentia during the Early Cambrian after an earlier, Neoproterozoic opening of the Iapetus Ocean, and was separated from the margin by a narrow oceanic tract (Humber seaway). Attempted subduction of the Dashwoods microcontinent prior to 488 Ma was followed by closure of the Humber seaway in the Taconian orogeny.
GEOSCAN ID212078