Sedimentary budgets of the Tanzania coastal basin and implications for uplift history of the East African rift system

Said, Aymen; Moder, C.; Clark, Stuart; Abdelmalak, Mohamed Mansour

doi:10.1016/j.jafrearsci.2015.08.012

Cited by 25 publications

(15 citation statements)

References 34 publications

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“…Also, the analysis of seismic data offshore Kenya and Somalia indicates that the Lamu Basin deep‐water fold‐and‐thrust belt was active from the Late Cretaceous to the Early Miocene, and almost all of the deformation occurred before the Late Pliocene (Cruciani and Barchi, ). In coastal Tanzania, the recorded high sedimentation rate at the Santonian/Campanian transition also indicates a tectonic uplift affecting the source areas during that time (Said et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Gondwana breakup: no evidence for a Davie Fracture Zone offshore northern Mozambique, Tanzania and Kenya

Klimke

Franke

2016

Terra Nova

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Plate tectonic reconstructions assume a major inactive transform fault, the Davie Fracture Zone, in the West Somali Basin, along which Madagascar is thought to have migrated southwards following Gondwana breakup in the Mesozoic. Based on the interpretation of reflection seismic data, we show that the Walu Ridge offshore Kenya and the Kerimbas Basin offshore northern Mozambique are tectonically unrelated to the southward motion of Madagascar and correlate with Late Cretaceous volcanism and inversion in Kenya and the evolution of the East African Rift System respectively. Offshore Tanzania, geophysical data do not show basement structures indicating the presence of a major transform fault. These results challenge the commonly supported transform margin concept and imply a more southerly pre-breakup position of Madagascar within Gondwana. Opening of the West Somali Basin by SW-propagating oblique rifting and seafloor spreading is proposed.

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Section: Discussionmentioning

confidence: 97%

Gondwana breakup: no evidence for a Davie Fracture Zone offshore northern Mozambique, Tanzania and Kenya

Klimke

Franke

2016

Terra Nova

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“…East Africa has had a turbulent geological history, with volcanism, uplift, and rifting shaping the geomorphology. Although earlier processes no doubt contributed to the modern landforms, much of the action is Neogene, and possibly only from the middle Miocene, as indicated by East African coastal sedimentation rates …”

Section: Tectonic Historymentioning

confidence: 99%

East African Cenozoic vegetation history

Linder

2017

Evolutionary Anthropology

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The modern vegetation of East Africa is a complex mosaic of rainforest patches; small islands of tropic-alpine vegetation; extensive savannas, ranging from almost pure grassland to wooded savannas; thickets; and montane grassland and forest. Here I trace the evolution of these vegetation types through the Cenozoic. Paleogene East Africa was most likely geomorphologically subdued and, as the few Eocene fossil sites suggest, a woodland in a seasonal climate. Woodland rather than rainforest may well have been the regional vegetation. Mountain building started with the Oligocene trap lava flows in Ethiopia, on which rainforest developed, with little evidence of grass and none of montane forests. The uplift of the East African Plateau took place during the middle Miocene. Fossil sites indicate the presence of rainforest, montane forest and thicket, and wooded grassland, often in close juxtaposition, from 17 to 10 Ma. By 10 Ma, marine deposits indicate extensive grassland in the region and isotope analysis indicates that this was a C grassland. In the later Miocene rifting, first of the western Albertine Rift and then of the eastern Gregory Rift, added to the complexity of the environment. The building of the high strato-volcanos during the later Mio-Pliocene added environments suitable for tropic-alpine vegetation. During this time, the C grassland was replaced by C savannas, although overall the extent of grassland was reduced from the mid-Miocene high to the current low level. Lake-level fluctuations during the Quaternary indicate substantial variation in rainfall, presumably as a result of movements in the intertropical convergence zone and the Congo air boundary, but the impact of these fluctuations on the vegetation is still speculative. I argue that, overall, there was an increase in the complexity of East African vegetation complexity during the Neogene, largely as a result of orogeny. The impact of Quaternary climatic fluctuation is still poorly understood.

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“…The Rovuma River originates from the uplifted flanks of the central Malawi Rift, flowing along Permo-Triassic basins. The Rovuma River fed the paleo-Rovuma delta since the late Oligocene-early Miocene 40,41 .…”

Section: Resultsmentioning

confidence: 99%

“…The plateau and rift-flank uplift of the EARS radically changed the topography of East Africa, reorganizing river catchments, drainage basins, and moderating climate 23,31 . Microfaunal and pollen assemblages sampled in exploration wells from the Rovuma delta offshore Mozambique indicate a change towards a cooler and wetter climate through the middle Eocene to Oligocene 50 , during the crustal uplift related to the EARS 41 . Recent studies from the western Indian Ocean also highlight the EARS' influence on offshore sedimentation along the margins of Tanzania and Mozambique 13,14 .…”

Section: Discussionmentioning

confidence: 99%

Large-scale mass wasting in the western Indian Ocean constrains onset of East African rifting

et al. 2020

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Faulting and earthquakes occur extensively along the flanks of the East African Rift System, including an offshore branch in the western Indian Ocean, resulting in remobilization of sediment in the form of landslides. To date, constraints on the occurrence of submarine landslides at margin scale are lacking, leaving unanswered a link between rifting and slope instability. Here, we show the first overview of landslide deposits in the post-Eocene stratigraphy of the Tanzania margin and we present the discovery of one of the biggest landslides on Earth: the Mafia mega-slide. The emplacement of multiple landslides, including the Mafia mega-slide, during the early-mid Miocene is coeval with cratonic rifting in Tanzania, indicating that plateau uplift and rifting in East Africa triggered large and potentially tsunamigenic landslides likely through earthquake activity and enhanced sediment supply. This study is a first step to evaluate the risk associated with submarine landslides in the region.

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Sedimentary budgets of the Tanzania coastal basin and implications for uplift history of the East African rift system

Cited by 25 publications

References 34 publications

Gondwana breakup: no evidence for a Davie Fracture Zone offshore northern Mozambique, Tanzania and Kenya

Gondwana breakup: no evidence for a Davie Fracture Zone offshore northern Mozambique, Tanzania and Kenya

East African Cenozoic vegetation history

Large-scale mass wasting in the western Indian Ocean constrains onset of East African rifting

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