Moho depth and crustal composition in Southern Africa

Southern Africa's crust exhibits significant heterogeneity, with distinct blocks characterized by varying thickness and composition that do not always align with surface tectonic features. Using seismic receiver functions from 85 stations, researchers identified ~20 crustal blocks, including the Tokwe block in the Zimbabwe Craton (35–38 km thick, Vp/Vs = 1.74–1.79) and the Tati block (47–51 km thick), which may reflect Archean deformation. The Limpopo Belt shows two blocks with similar thickness but differing Vp/Vs ratios, indicating extensive magmatic intrusions. The Bushveld Intrusion Complex lacks evidence of central magmatic intrusion, suggesting its lobes formed due to a thick crustal root (45–50 km). Central Kaapvaal's thin crust (35–40 km) and sharp Moho transition may imply pre-existing lower crust delamination. Notably, the Vredefort impact crater's exposed cross-section does not represent typical cratonic crust due to shallow Moho (34 km) and high Vp/Vs (~1.80), attributed to shock metamorphism.

Youssof, M., Thybo, H., Artemieva, I. M., & Levander, A. (2013). Moho depth and crustal composition in Southern Africa. Tectonophysics, 609, 267–287. https://doi.org/10.1016/j.tecto.2013.09.001