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Geophysics – Geodynamics

BRAMAGEO | Integrated Geophysical-Geodynamic study of the Northeastern Brazilian margin

Supercontinent breakup, rift formation, and seafloor spreading are essential aspects of Plate Tectonics and the Wilson Cycle. However, significant uncertainties remain regarding how rifts develop, break apart continents, and open new oceans. Additionally, the crustal structures and magmatic characteristics of rift basins, particularly in their distal regions, are not well understood.

The BRAMAGEO project focuses on the northeastern Brazilian rifted margin and the basins within this region, where many rift-related tectonic features can be found, including triple junctions, aborted rift arms (aulacogens), magma-poor and magma-rich basins, seaward-dipping reflectors (SDRs), hyperextended continental crust exposing lower crust and/or mantle, and proto to normal oceanic crust. The project investigates the influence of pre-rift inherited structures, such as cratons, orogenic belts, and existing structural elements (e.g., faults, shear zones, and foliation), on the development of these rifts and basins.

The project employs a state-of-the-art numerical modeling code, Kinedyn (Muldashev et al., 2021; Liu et al., 2022; Perez-Gussinye et al., 2023), which allows both dynamic and kinematic modeling, enabling the simulation of multichannel seismic reflection profiles (MCS) at the fault-block scale to address key research questions. The outcomes will provide an improved understanding of the history of deformation, magmatism, and sedimentation in the basins during the syn- and post-rift stages along the northeastern Brazilian margin and other rifted margins worldwide.

BRAMAGEO is a collaborative project between MARUM (Cen­ter for Mar­ine En­vir­on­mental Sci­ences), University of Bremen, Petrobras, and GEOMAR Helmholtz Centre for Ocean Research Kiel.

Dr. Erkan Gün, 2024-2027

Funding from Petrobras.

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Figure 1. Comparison of (a) a multichannel seismic (MCS) line along the West Iberia margin with (b) results of the sequential nudging approach to reconstruct rift dynamics at fault-block scale (Kinedyn), after 115 Myr of evolution. The interpretation of fault kinematics in the MCS line is incorporated during the dynamic model run, so that the model is nudged towards the MCS data observations. F1 to F7 are faults, B1 to B7 are fault blocks. Red–blue–white stripes show the deformation within the crust, the thick blue line is the Moho from the model. DR are deep reflections, D is detachment faults. Dredges and International Ocean Discovery Program wells are shown in panel a. Age of sediment is shown by colour variation in panel b. In the future, such models could be used to predict the pattern of hydrothermal circulation at margins and their consequences for element exchange and deposition of minerals within the sedimentary sections. Figure from Pérez-Gussinyé et al. (2023) and Liu et al. (2022).