Taking the pulse of planet earth: a proposal for a new multi-disciplinary flagship project in Canadian solid earth sciences

Geoscience Canada, Dec, 2004 by Wouter Bleeker

SUMMARY

Herein I propose a vision for a new multidisciplinary "big science" project for Canada's solid earth sciences. I call this proposed project: "Taking the Pulse of Planet Earth". At a modest cost, and over a 5 to 10 year life-span, it would aim at providing the most comprehensive and multidisciplinary knowledge base of the complete record of mafic magmatism in and around Canada, and through stimulating international cooperation, around the world.

A complete record of mafic magmatism (spatial distribution, ages, periodicities, rates, volume estimates, estimated geochemical fluxes to atmosphere and hydrosphere, tectonic settings, structural trends, sequence stratigraphic framework, evolving major and trace element compositions, evolving isotopic ratios, paleomagnetic information, paleo-intensities, associated ore deposits, etc.) constitutes critical input data for numerous first-order questions about the past and present evolution of our planet. Many of such questions relate to issues that are currently a focus of attention: global change, past climate extremes, complex Earth systems, planetary evolution, extinction events, flood volcanism, potential relationships with large impact events, and the discovery of new ore resources.

The proposed project is a focused, "smart", and highly efficient approach to solve a large number of these seemingly unrelated but first-order questions in contemporary earth science. At its core, it would have a large dating program, aiming to provide approximately 200 new, high-precision ages of mafic magmatic events across Canada and adjacent regions. A Supporting Geoscience grant system would ensure that other aspects of the magmatic record receive equal attention. Finally, I illustrate the impact this project would have on paleo-continental reconstructions. As part of this illustration, I synthesize existing data on two dyke swarms, the ca. 2.45 Ga Matachewan and Kaminak swarms, respectively, and propose a novel Superior-Hearne reconstruction within supercraton Superia.

SOMMAIRE

Je propose ci-contre l'idee d'un nouveau projet multidisciplinaire de grande envergure dans le domaine des sciences des roches solides au Canada. J'ai nomme ce projet << Prendre le pouls de la planete Terre>>. D'un cout modeste et s'echelonnant sur cinq a dix ans, ce projet constituerait la base de connaissances multidisciplinaire la plus complete de tout le repertoire des evenements magmatiques mafiques au Canada et a son pourtour, cela, en profitant des effets stimulant de la cooperation internationale.

Un repertoire complet des evenements magmatiques mafiques (distribution spatiale, ages, periodicites, taux, estimations des volumes, estimations geochimiques des flux dans l'atmosphere et l'hydrosphere, cadres tectoniques, styles structuraux, cadres stratigraphiques des sequences, compositions des suites evolutives des elements majeurs et en trace, evolution des ratios isotopiques, donnees paleomagnetiques, paleo-intensites, gisements associes, etc.) constitue un registre de donees de base cruciales pour nombres de grandes questions sur revolution passee et actuelle de notre planete. Plusieurs de ces grandes questions sont liees a des problemes actuels qui mobilisent l'attention, tels: les changements a l'echelle planetaire, les evenements climatiques extremes du passe, les systemes planetaires complexes, l'evolution de la planete, les grandes extinctions biotiques, les grands epanchements volcaniques, les liens eventuels avec de grands impacts meteoritiques, ainsi que la decouverte de nouvelles sources de minerai.

Le projet propose constitue une approche ciblee, << habile >>, et tres efficace permettant de solutionner un grand nombre de ces grands problemes, sans liens apparents, des geosciences contemporaines. Au coeur du projet on retrouve un grand programme de datation visant a etablir quelques 200 nouvelles datations de grande precision d'evenements magmatiques au Canada et dans les regions peripheriques. Un systeme de subvention d'appoint permettrait d'assurer que d'autres aspects de la problematique magmatique recoivent autant d'attention. Finalement, a titre d'illustration, je decris les repercussions escomptees d'un tel projet sur les reconstitutions paleo-continentales. Dans le cadre de cette illustration, je presente une synthese des donnees disponibles concernant deux reseaux de dykes, soit les reseaux de Matachewan et de Kaminak de 2,45 Ga, respectivement, et propose une nouvelle reconstitution Superieur-Hearne dans le super-craton Superia.

INTRODUCTION

LITHOPROBE, for more than two decades the premier flagship project of Canada's solid earth sciences, is winding down. Lithosphere-scale cross-sections have been gathered across the Canadian landmass and final syntheses are now being prepared (e.g., Percival et al., 2004). The inevitable ending of this project, on the heels of its success, will leave a growing vacuum across the Canadian earth science community at a time when competition for significant science funding is stronger than ever. Much of this competition revolves around highly visible "big science" projects in such fields as physics, astronomy, biochemistry and material science. Hence, we need to position ourselves to compete in this arena--we need a new flagship project. Here I will outline my vision for such a project, which I call "Taking the Pulse of Planet Earth" and which has at its core a large multidisciplinary study of all mafic magmatism through time. I use "mafic magmatism" as a shorthand here, but mean to include all mantle-derived magmatic activity other than steady-state arc magmatism; that is, all basalt ([ or -] komatiite)-dominated and (or) bimodal magmatism associated with divergent margins, or more generally extensional regimes, intraplate magmatic provinces, mantle plumes, anorogenic provinces, kimberlite and alkaline provinces.