Paleogeographic Reconstruction of the NUNA Supercontinent and the Assumption of "Orogenic Rigidity"

Johnston, S. T.; Lahtinen, R. et Saumur, B.M. (2022). « Paleogeographic Reconstruction of the NUNA Supercontinent and the Assumption of "Orogenic Rigidity" », dans GAC-MAC-IAH-CNC-CSPG 2022 Halifax Meeting: Abstracts, Volume 45 (GAC-MAC-IAH-CNC-CSPG, Halifax, 15-18 mai 2022), sous la dir. de Barr, S. p. 131.

Fichier(s) associé(s) à ce document :

	PDF (voir page 131) Télécharger (2MB)

Résumé

A common assumption in making paleogeographic reconstructions is that orogensmaintain a fixed shape during and after their formation. Hence map-view bends areinterpreted as primary features (promontories and re-entrants) despite studies ofwell-preserved and little overprinted Phanerozoic orogens in which it has beendemonstrated that some bends are products of deformation and oroclinal buckling.The assumption of ‘orogenic rigidity’ has, for example, informed attempts to recon-struct the Paleoproterozoic supercontinent, NUNA. The case for NUNA is strong.The 2.1 to 1.8 Ga orogens and juvenile crustal provinces characterize and are con-sistent with there having been links between most of the major continental blocksat that time. However, attempts to reconstruct NUNA have met with limited suc-cess, perhaps due in part to the assumption of orogenic rigidity. Our focus has beenon the NUNA-forming Trans-Hudson orogen of northeastern Laurentia and theSvecofennian orogen of Baltica. Both orogens are characterized by significant bendsand complicated geometry. In Baltica, oroclinal buckling affects only hot, juvenilearc-crust and appears to have overlapped with the final stages of ocean closure.Coeval deformation in adjacent cold, thick Archean lithosphere mainly consisted ofreactivation of older fault zones. In Greenland and Baffin Island the involvement ofmainly Archean crust suggests that dramatic changes in orientation and vergencedirection of Trans-Hudson orogenic belts likely, but not necessarily, reflect tectonicinheritance. Determining which bends are primary and which are secondary remainsa major and commonly unrecognized challenge in the reconstruction of supercon-tinents, including NUNA.

Type:	Communication, article de congrès ou colloque
Mots-clés ou Sujets:	Baffin, Groenland, tectonique
Unité d'appartenance:	Faculté des sciences > Département des sciences de la Terre et de l'atmosphère
Déposé par:	Benoit Saumur
Date de dépôt:	10 mars 2025 08:15
Dernière modification:	10 mars 2025 08:15
Adresse URL :	http://archipel.uqam.ca/id/eprint/18553

Modifier les métadonnées (propriétaire du document)

Statistiques