{"title":"Secular cooling and crystallization of partially molten Archaean continental crust over 1 Ga","authors":"Olivier Vanderhaeghe , Célia Guergouz , Cécile Fabre , Stéphanie Duchêne , David Baratoux","doi":"10.1016/j.crte.2019.07.002","DOIUrl":null,"url":null,"abstract":"<div><p>The protracted tectonic and magmatic record of cratons over the Archaean Eon has been classically interpreted in terms of long-lived shallow-dipping subduction or repeated mantle plumes. In this paper, we use the 1D conductive heat equation to model the evolution of the geotherm of a generic felsic-dominated Archaean cratonic nuclei solely considering the secular decay of radioactive isotopes (<sup>238</sup>U, <sup>235</sup>U, <sup>232</sup>Th, and <sup>40</sup>K), responsible for heat production in the crust. Using a range of plausible parameters for crustal thickness, lithospheric thickness, and surface heat flux, this modelling shows that Archaean crust was characterized by an initially high geothermal gradient at 3.5 Ga, with a Moho temperature close to 900 °C, and that it might have remained partially molten for about one billion years. The existence of a partially molten crust for an extended period of time offers an alternative option to shallow-dipping subduction or repeated mantle plumes for the understanding of the peculiar tectonic evolution of Archaean cratons marked by (i) protracted high-temperature metamorphism and magmatism associated with crustal differentiation, and (ii) widespread deformation characterized by structural domes attributed to the development of crustal-scale gravitational instabilities.</p></div>","PeriodicalId":50651,"journal":{"name":"Comptes Rendus Geoscience","volume":null,"pages":null},"PeriodicalIF":2.0000,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.crte.2019.07.002","citationCount":"15","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Comptes Rendus Geoscience","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S163107131930080X","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 15
Abstract
The protracted tectonic and magmatic record of cratons over the Archaean Eon has been classically interpreted in terms of long-lived shallow-dipping subduction or repeated mantle plumes. In this paper, we use the 1D conductive heat equation to model the evolution of the geotherm of a generic felsic-dominated Archaean cratonic nuclei solely considering the secular decay of radioactive isotopes (238U, 235U, 232Th, and 40K), responsible for heat production in the crust. Using a range of plausible parameters for crustal thickness, lithospheric thickness, and surface heat flux, this modelling shows that Archaean crust was characterized by an initially high geothermal gradient at 3.5 Ga, with a Moho temperature close to 900 °C, and that it might have remained partially molten for about one billion years. The existence of a partially molten crust for an extended period of time offers an alternative option to shallow-dipping subduction or repeated mantle plumes for the understanding of the peculiar tectonic evolution of Archaean cratons marked by (i) protracted high-temperature metamorphism and magmatism associated with crustal differentiation, and (ii) widespread deformation characterized by structural domes attributed to the development of crustal-scale gravitational instabilities.
期刊介绍:
Created in 1835 by physicist François Arago, then Permanent Secretary, the journal Comptes Rendus de l''Académie des sciences allows researchers to quickly make their work known to the international scientific community.
It is divided into seven titles covering the range of scientific research fields: Mathematics, Mechanics, Chemistry, Biology, Geoscience, Physics and Palevol. Each series is led by an editor-in-chief assisted by an editorial committee. Submitted articles are reviewed by two scientists with recognized competence in the field concerned. They can be notes, announcing significant new results, as well as review articles, allowing for a fine-tuning, or even proceedings of symposia and other thematic issues, under the direction of invited editors, French or foreign.