Tracing Archean crustal growth and paleoproterozoic reworking in the Divinópolis Complex, southern São Francisco Craton
Posted on 2025-10-16 - 05:53
Understanding Earth's Archean crust and mantle is fundamental to reconstructing terrestrial geodynamic evolution. However, these ancient rocks have undergone extensive metamorphic and metasomatic events that may overprint primary lithological and structural features, posing challenges to the interpretation of their original composition. The Divinópolis Complex represents a long-lived, polygenetic magmatic-metamorphic block in the São Francisco Craton, poorly understood but with large amount of exposed newly identified gneisses and granites. In this study, we present integrated fieldwork, geophysics and LA-ICP-MS U–Pb ages of zircon and monazite. The Complex consists of gneisses and migmatites TTG units intruded by monzogranite and syenogranite, revealing multiple magmatic episodes. Differentiation of tonalitic magma into the upper crust has generated a TTG crust at 2915–2860 Ma followed by another one from 2800 to 2760 Ma. After 2760 Ma extensive generation of granodiorites and granites from potassic shallow sources indicate crustal and mantle differentiation. The last potassic pulses occur between 2650 and 2610 and mark the period of tectonic quiescence. The crust was reactivated at 2.06–2.04 Ga, mainly along deep shear zones between major blocks. These events share parallels with other cratons like Kaapvaal, Yilgarn, and North China, transitioning from plume to plate-tectonic dominance.
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Melo-Silva, P.; Amaral, W. S.; Galé, M. G.; Motta, J. G.; Oliveira, E. P. (2025). Tracing Archean crustal growth and paleoproterozoic reworking in the Divinópolis Complex, southern São Francisco Craton. Geological Society of London. Collection. https://doi.org/10.6084/m9.figshare.c.8092791.v1