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TitleThe North America mid-Cretaceous kimberlite corridor: wet, edge-driven decompression melting of an OIB-type deep mantle source
AuthorKjarsgaard, B AORCID logo; Heaman, L M; Sarkar, C; Pearson, D G
SourceGeochemistry, Geophysics, Geosystems (G3) vol. 18, issue 7, 2017 p. 2727-2747,
Alt SeriesNatural Resources Canada, Contribution Series 20170071
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html; docx (Microsoft® Word®); xls (Microsoft® Excel®)
ProvinceNunavut; Saskatchewan
NTS57; 58; 65; 66; 67; 68; 72; 73; 74; 75; 76; 77; 82; 83; 84; 85
AreaNorth America; Somerset Island; Kansas; Canada; United States of America
Lat/Long WENS-114.0000 -90.0000 75.0000 30.0000
Subjectsgeochronology; tectonics; structural geology; bedrock geology; lithology; igneous rocks; intrusive rocks; kimberlites; radiometric dating; uranium lead dating; zircon dates; rubidium strontium dating; isotopic studies; strontium; neodymium; hafnium; tectonic setting; magmatism; source areas; mantle; attenuation; lithosphere; metasomatism; partial melting; emplacement; subduction; downgoing slab; convection; volcanism; fluid flow; structural controls; models; plate margins; carbon dioxide; whole rock analyses; geodynamics; pressure-temperature conditions; North American Craton; Sask Craton; Interior Seaway of North America; Farallon Slab; Water; Phanerozoic; Mesozoic; Cretaceous
Illustrationsgeoscientific sketch maps; tables; graphs; schematic cross-sections; phase diagrams
ProgramGEM: Geo-mapping for Energy and Minerals Diamonds
Released2017 07 27
AbstractThirty 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.
Summary(Plain Language Summary, not published)
We determined the age of kimberlite intrusions and volcanics in central Canada (Somerset Island, NU and Saskatchewan)and propose a model for the source region of the melts and the initiation of magmatism

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