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TitreThe North America mid-Cretaceous kimberlite corridor: wet, edge-driven decompression melting of an OIB-type deep mantle source
AuteurKjarsgaard, B A; Heaman, L M; Sarkar, C; Pearson, D G
SourceGeochemistry, Geophysics, Geosystems (G3) vol. 18, issue 7, 2017 p. 2727-2747, https://doi.org/10.1002/2016GC006761
Année2017
Séries alt.Ressources naturelles Canada, Contribution externe 20170071
ÉditeurBlackwell Publishing Ltd
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1002/2016GC006761
Mediapapier; en ligne; numérique
Formatspdf (Adobe® Reader®); html; docx (Microsoft® Word®); xls (Microsoft® Excel®)
ProvinceNunavut; Saskatchewan
SNRC57; 58; 65; 66; 67; 68; 72; 73; 74; 75; 76; 77; 82; 83; 84; 85
Lat/Long OENS-114.0000 -90.0000 75.0000 30.0000
Sujetsgéologie du substratum rocheux; lithologie; roches ignées; roches intrusives; kimberlites; datation radiométrique; datation au uranium-plomb; datations au zircon; datation au rubidium-strontium; etudes isotopiques; strontium; néodyme; hafnium; cadre tectonique; magmatisme; régions émettrices; manteau terrestre; attenuation; lithosphère; métasomatose; fusion partielle; mise en place; subduction; panneau orienté vers le bas; convection; volcanisme; fluage; contrôles structuraux; modèles; marges plaques; gaz carbonique; analyses des roches totales; géodynamiques; conditions de pression-température; Craton de l'Américque du Nord; Craton de Sask ; Eau; géochronologie; tectonique; géologie structurale; Phanérozoïque; Mésozoïque; Crétacé
Illustrationsgeoscientific sketch maps; tables; graphs; schematic cross-sections; phase diagrams
ProgrammeDiamands, GEM : La géocartographie de l'énergie et des minéraux
Diffusé2017 07 27
Résumé(disponible en anglais seulement)
Thirty new high-precision U-Pb perovskite and zircon ages from kimberlites in central North America delineate a corridor of mid-Cretaceous (115-92 Ma) magmatism that extends ~4000 km from Somerset Island in Arctic Canada through central Saskatchewan to Kansas, USA. The least contaminated whole rock Sr, Nd, and Hf isotopic data, coupled with Sr isotopic data from groundmass perovskite indicates an exceptionally limited range in Sr-Nd-Hf isotopic compositions, clustering at the low epsilon-Nd end of the OIB array. These isotopic compositions are distinct from other studied North American kimberlites and point to a sublithospheric source region. This mid-Cretaceous kimberlite magmatism cannot be related to mantle plumes associated with the African or Pacific large low-shear wave velocity province (LLSVP). All three kimberlite fields are adjacent to strongly attenuated lithosphere at the edge of the North American craton. This facilitated edge-driven convection, a top-down driven processes that caused decompression melting of the transition zone or overlying asthenosphere. The inversion of ringwoodite and/or wadsleyite and release of H2O, with subsequent metasomatism and synchronous wet partial melting generates a hot CO2 and H2O-rich protokimberlite melt. Emplacement in the crust is controlled by local lithospheric factors; all three kimberlite fields have mid-Cretaceous age, reactivated major deep-seated structures that facilitated kimberlite melt transit through the lithosphere.
Résumé(Résumé en langage clair et simple, non publié)
Les âges des intrusions de kimberlite et des roches volcaniques ont été determines dans le centre du Canada (Ile de Somerset, NU et Saskatchewan) et un modèle a été proposé pour la région source des roches fondues et l'initiation du magmatisme.
GEOSCAN ID300856