Holocene explosive eruptions in the Rungwe Volcanic Province, Tanzania

Fontijn, Karen; Ernst, Gérald J.; Elburg, Marlina; Williamson, David; Abdallah, Edister A; Kwelwa, Shimba; Mbede, Evelyne; Jacobs, Patric

doi:10.1016/j.jvolgeores.2010.07.021

Cited by 55 publications

(43 citation statements)

References 45 publications

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“…1073/pnas.1301474110/-/DCSupplemental. metals and distinctly different from the RVP tephra, which are predominantly trachydacitic in composition (26), or from any other known contemporary East African rhyolitic tephra sources (27,28) (Fig. 3B).…”

Section: Resultsmentioning

confidence: 80%

Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka

Lane

Chorn

Johnson

2013

Proc. Natl. Acad. Sci. U.S.A.

181

111

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The most explosive volcanic event of the Quaternary was the eruption of Mt. Toba, Sumatra, 75,000 y ago, which produced voluminous ash deposits found across much of the Indian Ocean, Indian Peninsula, and South China Sea. A major climatic downturn observed within the Greenland ice cores has been attributed to the cooling effects of the ash and aerosols ejected during the eruption of the Youngest Toba Tuff (YTT). These events coincided roughly with a hypothesized human genetic bottleneck, when the number of our species in Africa may have been reduced to near extinction. Some have speculated that the demise of early modern humans at that time was due in part to a dramatic climate shift triggered by the supereruption. Others have argued that environmental conditions would not have been so severe to have such an impact on our ancestors, and furthermore, that modern humans may have already expanded beyond Africa by this time. We report an observation of the YTT in Africa, recovered as a cryptotephra layer in Lake Malawi sediments, >7,000 km west of the source volcano. The YTT isochron provides an accurate and precise age estimate for the Lake Malawi paleoclimate record, which revises the chronology of past climatic events in East Africa. The YTT in Lake Malawi is not accompanied by a major change in sediment composition or evidence for substantial temperature change, implying that the eruption did not significantly impact the climate of East Africa and was not the cause of a human genetic bottleneck at that time.

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Section: Resultsmentioning

confidence: 80%

Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka

Lane

Chorn

Johnson

2013

Proc. Natl. Acad. Sci. U.S.A.

181

111

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“…The regional stratigraphy of volcanic deposits was first examined by Harkin (1960). The detailed Holocene eruptive history of Rungwe was recently studied by Fontijn et al (2010b), who showed that Rungwe has had at least eight moderate-to large-scale explosive eruptions in the last~4,000 years. The most voluminous one was the ca.…”

Section: Introductionmentioning

confidence: 99%

“…The RP has a trachytic composition. Well before the RP eruption, Rungwe volcano was affected by a sector collapse that generated a debris avalanche (Fontijn et al 2010b). This sector collapse resulted in the formation of a summit crater depression ca.…”

Section: Introductionmentioning

confidence: 99%

“…Rungwe has, however, been regularly active throughout the late Holocene. All existing evidence points to a very active volcano with typical repose times of a few hundreds to a thousand years, separating violent strombolian to Plinian-style explosive eruptions (Fontijn et al 2010b). Apart from the risk associated with pyroclastic density currents, Rungwe, the foothills of which are densely populated and which is not monitored, poses a similar threat from extensive tephra fallout, as was the case at Mt.…”

Section: Introductionmentioning

confidence: 99%

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The ~4-ka Rungwe Pumice (South-Western Tanzania): a wind-still Plinian eruption

et al. 2011

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The ~4-ka trachytic Rungwe Pumice (RP) deposit from Rungwe Volcano in South-Western Tanzania is the first Plinian-style deposit from an African volcano to be closely documented focusing on its physical characterization. The RP is a mostly massive fall deposit with an inversely graded base. Empirical models suggest a maximum eruption column height HT of 30.5–35 km with an associated peak mass discharge rate of 2.8–4.8×108 kg/s.Analytical calculations result in HT values of 33±4 km(inversion of TEPHRA2 model on grain size data) corresponding to mass discharge ranging from 2.3 to 6.0×10^8 kg/s. Lake-core data allow extrapolation of the deposit thinning trend far beyond onland exposures. Empirical fitting of thickness data yields volume estimates between 3.2 and 5.8 km3 (corresponding to an erupted mass of 1.1–2.0×10^12 kg), whereas analytical derivation yields an erupted mass of 1.1×10^12 kg (inversion of TEPHRA2 model). Modelling and dispersal maps are consistent with nearly no-wind conditions during the eruption. The plume corner is estimated to have been ca. 11–12 km from the vent. After an opening phase with gradually increasing intensity, a high discharge rate was maintained throughout the eruption, without fountain collapse as is evidenced by a lack of pyroclastic density current deposits

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“…Fontijn et al 2012). Only two of Ngozi's deposits could be dated so far through radiocarbon analysis, the 10-12 ka Kitulo Pumice (a fallout deposit) and the\1 ka Ngozi Tuff (a pyroclastic density current deposit; Fontijn et al 2010). The exact relationship between the Ituwa Surge deposits and the two dated Ngozi deposits remains unclear.…”

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confidence: 99%