Anatomy of the transpressional Dom Feliciano Belt and its pre-collisional isotopic (Sr-Nd) signatures: A contribution towards an integrated model for the Brasiliano/Pan-African orogenic cycle

The Dom Feliciano Belt evolution is reviewed based on cross-sections, space-time diagrams, P-T paths, and Sr-Nd isotopic data of pre-collisional metaigneous rocks. The belt is divided into northern, central and southern sectors, subdivided into tectonic domains, developed at Neoproterozoic pre-, syn- and post-collisional stages. The northern sector foreland pre-collisional setting represents a rift, with tholeiitic (meta)volcanic rocks (-800 Ma) chronocorrelated to hinterland intermediate and acidic orthogneisses of high-K calc-alkaline arc signature. In contrast, the central sector records a complete section from the forearc towards the back-arc region during pre-collisional times. In the western domain, ophiolites (-920 Ma) are associated with arc-related orthogneisses and metavolcanic rocks (880-830 Ma; 760-730 Ma). At back-arc position, continental arc-related magmatism (800-780 Ma) is registered by hinterland orthogneisses and central foreland metavolcanic rocks. Ophiolites on the hinterland opposite side comprise two compositional groups, with N-MORB and supra subduction signature, interpreted as a back-arc basin record (-750 Ma). The pre-Neoproterozoic basement of the whole belt is correlated with the Nico Perez Terrane and Luis Alves Block (Archean to Mesoproterozoic, with Congo Craton affinity). This contrasts with the Piedra Alta Terrane (Rio de La Plata Craton, only Paleoproterozoic), westernmost Uruguay. The suture between the Piedra Alta and Nico Perez terranes is correlated with the suture zone in the westernmost central sector. Transpression affected both foreland and hinterland during collision (660-640 Ma), with high-T/low-P hinterland progressive exhumation, whilst foreland low- to medium-grade correlated sequences record underthrusting. Post-collisional processes included magmatism throughout the belt (640-580 Ma), strain partitioning along strike-slip shear zones, and foreland basin fill. Late tectono-metamorphic and magmatic processes (560-540 Ma) were attributed to the Kalahari Craton collision. Arc magmatism migration due to subduction angle variations suggests modern-style plate tectonics during Gondwana amalgamation. Diachronism and kinematic inversion are characteristic of an oblique convergent multi-plate orogenic system. CO 2023 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Automated summary

The evolution of the Dom Feliciano Belt was reviewed based on various geological data. The belt is divided into three sectors and shows different tectonic domains at different stages of collision. The study reveals the geological processes and characteristics of different regions within the belt, as well as comparisons with other terranes.