Crustal heat production in the Superior Province, Canadian Shield, and in North America inferred from heat flow data - art. no. B04401 | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Crustal heat production in the Superior Province, Canadian Shield, and in North America inferred from heat flow data - art. no. B04401

Type de publication:

Journal Article

Source:

Journal of Geophysical Research Solid Earth, Volume 111, Ticket B4, p.1-20 (2006)

ISBN:

0148-0227

URL:

http:/www.agu.org/

Mots-clés:

Trans-hudson-orogen; abitibi-greenstone-belt; nd-isotopic-evidence; u-pb-zircon; thermal-structure; northwestern-ontario; slave-province; metasedimentary-rocks; continental-growth; tectonic-evolution

Résumé:

<p>[1] Measurements of heat flow and U, Th, K concentrations are used to determine the amount of heat generated in various belts of the Superior Province, the largest Archean craton on Earth. These data allow estimates of the average crustal heat production and indicate compositional differences between upper and lower crustal assemblages. The bulk average heat production of the Superior Province crust is 0.64 mu W m(-3) and is almost the same in different belts of slightly different ages, illustrating the remarkable uniformity of crust-building mechanisms. In the wider context of the North American continent, the bulk crustal heat production decreases from 1.0 mu W m(-3) in the oldest Slave Province to a minimum of 0.55 mu W m(-3) in the Paleo-Proterozoic Trans-Hudson Orogen. It increases in younger provinces, culminating with a high value of 1.05 mu W m(-3) in the Phanerozoic Appalachian Province. In all provinces, U and Th enrichment is systematically associated with sedimentary accumulations. A crustal differentiation index is obtained by calculating the ratio between the average values of heat production at the surface and in the bulk crust. The differentiation index is correlated with the bulk average heat production, which suggests that crustal differentiation processes are largely driven by internal radiogenic heat.</p>

Notes:

Inst Phys Globe, Lab Dynam Syst Geol, F-75252 Paris 05, France; Univ Quebec, GEOTOP, UQAM McGill, Montreal, PQ H3C 3P8, CanadaArticleEnglish