We have published in collaboration with Carlos E. Ganade from the Geological Survey of Brazil a paper in Nature, communications earth &environment examining the consequences of magmatic flare-ups on the deep arc environment. We used petrochronological techniques to investigate the root of a continental arc exposed in the Kabyé Massif in Togo (see figure below).

Simplified cross section of the Kabyé continental arc root showing the transition from garnet-bearing rocks on the left (west) to garnet-free metagabbros on the right (east).

In this study, we demonstrate that gabbros intruded 670 million years ago at 20–25 km depth were metamorphosed to eclogites by 620 million years ago at 65–70 km depth. This burial stage was coeval with extensive magmatism at 20–40 km depth, indicative of a flare-up event which peaked just prior to the subduction of the continental margin

Igneous inflation and arc thickening during different stages of subduction: (A) Amount of water in the different sections of the subducted material; (B) forward thermodynamic simulation showing the progressive ecoligtisation of a upper arc metagabbro.

The results presented in this paper provide insights into the interplay of fast crustal growth and thickening in response to a magmatic flare-up at the termination of a long-lived subduction system

Find out more

Ganade, C., Lanari, P., Rubatto, D., Hermann, J., Weinberg, R., Basei, M., Tesser, L., Caby, R., Agbossoumonde, Y., Ribeiro, C. (2021). Continental arc thickening and inflation during magmatic flare-up. Communications Earth & Environment, 2, 41. Download pdf | Visit the journal webpage

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