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Large scale pantelleritic ash flow eruptions during the Late Miocene in central Kenya and evidence for significant environmental impact

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Relation http://oar.icrisat.org/9770/
http://dx.doi.org/10.1016/j.gloplacha.2016.08.006
10.1016/j.gloplacha.2016.08.006
 
Title Large scale pantelleritic ash flow eruptions during the Late Miocene in central Kenya and evidence for significant environmental impact
 
Creator Claessens, L
Veldkamp, A
Schoorl, J M
Wijbrans, J R
van Gorp, W
Macdonald, R
 
Subject Others
 
Description In the area south-east of Mount Kenya, four previously unrecorded peralkaline rhyolitic (pantelleritic) ash flow tuffs have been located. These predominantly greyish welded and non-welded tuffs form up to 12 m thick units, which are sometimes characterized by a basal vitrophyre. The four flow units yielded 40Ar/39Ar ages ranging from 6.36 to 8.13 Ma, indicating a period of ~ 1.8 Ma of pantelleritic volcanic activity during the Late Miocene in central Kenya. Tentative compositional and age correlations with other known tuff deposits suggest that the pantelleritic tuffs originally covered 40,000 km2 in central Kenya, extending much further than earlier recorded Pliocene tuffs. This newly identified magmatic phase occurred between the phonolitic flood eruptions (16–8 Ma) and the Pliocene tuff eruptions (6–4 Ma). The occurrence of multiple ash flow tuff deposits up to 150 km away from the inferred eruptive center(s) in the central sector of the Kenya Rift, indicates multi-cyclic peralkaline supereruptions during the Late Miocene. By analogy with more recent pantelleritic eruptions, the tuffs are thought to have been sulfur-rich; during eruption, they formed stratospheric aerosols, with significant environmental impact. The timing of the eruptions coincides with the shift towards more savannah-dominated environments in East Africa.
 
Publisher Elsevier B.V.
 
Date 2016-10
 
Type Article
PeerReviewed
 
Format application/pdf
 
Language en
 
Rights —
 
Identifier http://oar.icrisat.org/9770/1/Large%20scale%20pantelleritic%20ash%20flow.pdf
Claessens, L and Veldkamp, A and Schoorl, J M and Wijbrans, J R and van Gorp, W and Macdonald, R (2016) Large scale pantelleritic ash flow eruptions during the Late Miocene in central Kenya and evidence for significant environmental impact. Global and Planetary Change, 145. pp. 30-41. ISSN 09218181