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TitlePreliminary geochemical results on mantle metal mobility
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AuthorLawley, C J M; Kjarsgaard, B A; Zagorevski, A; Pearson, G; Waterton, P; Savard, D; Jackson, S E; Yang, Z; Zhang, S; Tschirhart, V
SourceTargeted Geoscience Initiative: 2017 report of activities, volume 1; by Rogers, N (ed.); Geological Survey of Canada, Open File 8358, 2018 p. 127-131, (Open Access)
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
RelatedThis publication is contained in Rogers, N; (2018). Targeted Geoscience Initiative: 2017 report of activities, volume 1, Geological Survey of Canada, Open File 8358
File formatpdf
ProvinceBritish Columbia; Ontario
NTS32D; 32E; 104J; 104K; 104N; 104O
AreaAtlin; Kirkland Lake
Lat/Long WENS-134.0000 -130.0000 60.0000 58.0000
Lat/Long WENS -80.0000 -80.0000 48.5000 48.0000
Subjectseconomic geology; igneous and metamorphic petrology; geochemistry; mineralogy; mineral deposits; mineral potential; mineral exploration; ore controls; ore mineral genesis; gold; nickel; copper; base metals; mantle; ophiolites; kimberlites; inclusions; host rocks; source rocks; isotopic studies; lead isotope ratios; clinopyroxene; olivine; electron probe analyses; mass spectrometer analysis; scanning electron microscope analyses; spectroscopic analyses; bedrock geology; lithology; igneous rocks; intrusive rocks; granites; tonalites; ultramafic rocks; Canadian Cordillera; Cache Creek Terrane; Canadian Shield; Superior Province; Abitibi Subprovince; Kirkland Lake Kimberlite Field; Blake River Group; Tisdale Group; Kidd-munro Assemblage; ore systems approach; metal mobility; platinum group elements (PGE); mantle-derived melts; xenocrysts; rhenium-osmium isotopic ratios; refertilization; lattice substitution; Phanerozoic; Mesozoic; Precambrian; Proterozoic
Illustrationslocation maps; geoscientific sketch maps; photographs; photomicrographs
ProgramTargeted Geoscience Initiative (TGI-5), Knowledge Management Coordination
ProgramTargeted Geoscience Initiative (TGI-5), Gold systems
Released2018 01 19
AbstractProcesses operating within mantle source regions likely impact the fertility of ore-bearing melts, although the precise link between mantle conditioning and ore genesis remain poorly understood. New fieldwork and isotopic (Re-Os and Pb-Pb) results for ultramafic samples from young (Mesozoic), ophiolitic mantle near Atlin British Columbia, document ancient (i.e. Paleoproterozoic and younger), refractory mantle domains hosted within variably depleted harzburgite. The metal endowment of these distinct mantle segments and the microscale distribution of gold, platinum group elements and base metals are the focus of on-going study.
Field-based research at Atlin complements chemical analysis of kimberlite-hosted mantle olivine and clinopyroxene xenocrysts. These mantle fragments provide a snapshot of the ancient, sub-continental lithospheric mantle beneath the Neoarchean Abitibi sub-province (Kirkland Lake kimberlite field). Geochemical depth profiles, based on preliminary in situ geochemical results of the least-altered xenocrysts, suggest that high temperature olivine is a significant silicate mineral host for some of the so-called chalcophile elements at depth (e.g. Cu and Zn). Other metals, including a rare subset of xenocrysts that yield concentrations for gold and platinum at or above the analytical detection limit (1-5 ppb), occur as micro-inclusions. The distribution of metal-bearing mineral phases within the mantle and, the micro-scale setting of metals within those phases (e.g. mineral inclusions versus lattice substitution), may control the variable metallic endowment of mantle-derived melts in ancient and modern settings.