KMMA literatuur elders gepubliceerd
Beschrijving
Delvaux, D. 2001. ‘Karoo rifting in western Tanzania: precursor of Gondwana breakup ?’. Contributions to Geology and Paleontology of Gondwana. In honour of Prof. Dr. Helmut Wopfner. Cologne : Universität zu Köln, pp. 111-125. (PR) ISBN: 3-934027-07-5.
Chapter in an edited book / Article in an edited book
The Karoo basin system in the NW-trending Ubende Belt in Tanzania and East Congo is a manifestation of the early stage of Gondwana break-up in East-Central Africa. The Karoo tectonic evolution of the Tanganyika-Rukwa-Malawi (TRM) zone in the East African rift was re-evaluated. A new model of evolution for the Karoo period (Late Carboniferous - Triassic) in the Ubende belt is presented. Instead of a former model of transcurrent basin formation in transtensional setting, an evolution in three successive tectonic stages is proposed. Karoo basins, much larger than the remaining ones, formed initially as a result of tectonically controlled subsidence during the Late Carboniferous - Permian and were filled by fluvial-deltaic to lacustrine sediments. Along the Ubende belt, they probably formed two major basin systems: the Kalemie - Lukuga - South Tanganyika (KLT) and the Rukwa - Songwe - North Malawi (RSM)troughs. Karoo sedimentation in the Ubende belt ended by Late Permian-Early Triassic transpressional inversion which caused strike-slip dislocation and tilting of the basins, particularly well observed in the Namwele-Mkomolo coalfield and also reported for the Congo basin (Cuvette centrale). In the NE-trending Karoo rift basins of Zambia and southeast Tanzania it caused a sedimentation gap and slight unconformities. This transpressional inversion is a good indication that intraplate compressional deformation was transmitted to the foreland of the palaeo-Pacific active margin of Gondwana during the Permo-Triassic transition. The tectonic inversion had a relatively short duration and was ollowed by a long period of regional uplift and denudation in the Ubende belt during the Triassic-Early Jurassic, with formation of the "Gondwana" morphological surface. In southeast Tanzania, sedimentation continued, probably until Early Jurassic times, prefiguring the future crustal failure between Western and Eastern Gondwana.