EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

The architecture of the lithospheric mantle controlled the emplacement of the Central Atlantic Magmatic Province

Andrea Boscaini1, Andrea Marzoli2, Hervé Bertrand3, Massimo Chiaradia4, Fred Jourdan5, Manuele Faccenda1, Christine Meyzen1, Sara Callegaro6, and Lina Serrano Durán7
Andrea Boscaini et al.
  • 1Dipartimento di Geoscienze, Università di Padova, 35131 Padova, Italy (
  • 2Dipartimento Territorio e Sistemi Agro-Forestali, Università di Padova, 35020 Legnaro, Italy
  • 3Univ Lyon, ENSL, Univ Lyon 1, CNRS, LGL-TPE, F-69007 Lyon, France
  • 4Département des Sciences de la Terre, Université de Genève, Rue des Maraichers 13, 1205 Genève, Switzerland
  • 5Western Australian Argon Isotope Facility, School of Earth and Planetary Sciences & JdL Centre & SSTC & TIGeR, Curtin University, GPO Box U1987, Perth, WA 6845, Australia
  • 6Centre for Earth Evolution and Dynamics, University of Oslo, Oslo, 0371, Norway
  • 7ALO Advisors, 7823 Alhambra Drive Bradenton, FL 34209, USA

Large Igneous Provinces (LIPs) represent exceptionally brief (<1 Ma) voluminous magmatic events that punctuate Earth history, frequently leading to continental break-up, global climate changes and, eventually, mass extinctions. Most LIPs emplaced in continental settings are located near cratons, begging the question of a potential control of thick lithosphere on mantle melting dynamics. In this study we discuss the case of the Central Atlantic Magmatic Province (CAMP), emplaced in the vicinity of the thick lithospheric keels of the Precambrian cratons forming the central portion of Pangea prior to the opening of the Central Atlantic Ocean. In particular, we focus on CAMP magmas of the Prevalent group, ubiquitous all over the province, and of the Tiourjdal and High-Ti groups, emplaced (respectively) at the edges of the Reguibat and Leo-Man shields in north-western Africa, and the Amazonian and São Luis cratons in South America. As imaged by recent tomographic studies, there is a strong spatial correlation between most CAMP outcrops at surface and the edges of the thick cratonic keels. Geochemical modelling of trace element and isotopic compositions of CAMP basalts suggests a derivation by partial melting of a Depleted MORB Mantle (DMM) source enriched by recycled continental crust (1-4%) beneath a lithosphere of ca. 80 km. Melting under a significantly thicker lithosphere (>110 km) cannot produce magmas with chemical compositions similar to those of CAMP basalts. Therefore, our results suggest that CAMP magmatism was produced by asthenospheric upwelling along the deep cratonic keels and subsequent decompression-induced partial melting in correspondence with thinner lithosphere. Afterwards, lateral transport of magma along dykes or sills led to the formation of shallow intrusions and lava flows at considerable distances from the source region, possibly straddling the edges of the cratonic lithosphere at depth. Overall, the variations of the lithospheric thickness (i.e., the presence of stable thick cratonic keels juxtaposed to relatively thinner lithosphere) appear to play a primary role for localizing mantle upwelling and partial melting during large-scale magmatic events like the CAMP.

How to cite: Boscaini, A., Marzoli, A., Bertrand, H., Chiaradia, M., Jourdan, F., Faccenda, M., Meyzen, C., Callegaro, S., and Serrano Durán, L.: The architecture of the lithospheric mantle controlled the emplacement of the Central Atlantic Magmatic Province, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9813,, 2022.