Linking the deep structures of the cratons of Africa and South America by integrated geophysical modelling
Final Report Abstract
In our project, we studied the cratons of South America and Africa by (i) satellite gravity inversion and (ii) thermo-compositional modelling. Our novel satellite gravity inversion uses seismic tomography in form of a regionalization map, in turn based on cluster analysis, as constraint and allows hereby to laterally vary the density contrast in the inversion. While inverting for a single density contrast is a simplification, it provides first insights into the lithospheric architecture, which is in focus of the dedicated thermo-compositional modelling. Here, seismic tomography and seismic depth estimates are used as constraint as before, but additional sources in the lithosphere are addressed. The results show that the crustal and upper mantle of the cratons of South America and Africa is more complex than previously thought and that their tectonic evolution is less homogeneous. This is also illustrated by studying the passive margin architecture and opening of the South Atlantic as this allows to enhance the structural similarities between the cratons. The break-up of Central Gondwana did affect the cratons, but structural similarities still exists between the two sides of the Atlantic. The results of the project hold the promise for an improve general understanding of the evolution of cratons, when applied on a global scale as done already for the satellite gravity gradient inversion.
Publications
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2020. Sensitivity analysis of gravity gradient inversion of the Moho depth - A case example for the Amazonian Craton. Geophysical Journal International, 221 (3), 1896–1912
Haas, P., Ebbing, J., Szwillus, W.
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2021. A Thermo‐Compositional Model of the Cratonic Lithosphere of South America. Geochemistry, Geophysics, Geosystems, 22(4), e2020GC009307
Finger, N. P., Kaban, M. K., Tesauro, M., Haeger, C., Mooney, W. D., & Thomas, M.
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2021. Two-step gravity inversion reveals variable architecture of African cratons. Frontiers in Earth Science. Front. Earth Sci. 9:696674
Haas, P., Ebbing, J., Celli, N., Rey, P.
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(2022). A Thermo‐Compositional Model of the African Cratonic Lithosphere. Geochemistry, Geophysics, Geosystems, e2021GC010296
Finger, N. P., Kaban, M. K., Tesauro, M., Mooney, W. D., & Thomas, M.
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2022: Linking the deep structures of the South American and African cratons by satellite gravity data. Dissertation an der CAU Kiel
Haas, P.
