eprintid: 9770
rev_number: 11
eprint_status: archive
userid: 1305
dir: disk0/00/00/97/70
datestamp: 2016-11-10 05:14:49
lastmod: 2017-04-18 09:26:56
status_changed: 2016-11-10 05:14:49
type: article
metadata_visibility: show
contact_email: Library-ICRISAT@CGIAR.ORG
creators_name: Claessens, L
creators_name: Veldkamp, A
creators_name: Schoorl, J M
creators_name: Wijbrans, J R
creators_name: van Gorp, W
creators_name: Macdonald, R
icrisatcreators_name: Claessens, L
affiliation: Soil Geography and Landscape group, Wageningen University (Wageningen)
affiliation: University of Twente (Enschede)
affiliation: Department of Earth Science, Vrije Universiteit (Amsterdam)
affiliation: ICRISAT (Nairobi)
affiliation: Environmental Science Division, Lancaster University (Lancaster)
affiliation: Faculty of Geology, University of Warsaw (Warszawa)
country: The Netherlands
country: Kenya
country: UK
country: Poland
title: Large scale pantelleritic ash flow eruptions during the Late Miocene in central Kenya and evidence for significant environmental impact
ispublished: pub
subjects: s2
divisions: CRPS5
crps: crp1.11
full_text_status: restricted
keywords: Tuff; Ash flow; Ignimbrite; Vitrophyre; Peralkaline rhyolites; 40Ar/39Ar geochronology
note: Alan Deino is thanked for providing more background information
about the Mpesida tuffs in the Tugen Hills. Fieldwork was partly supported
by the CGIAR Research Program on Climate Change, Agriculture
and Food Security (CCAFS).We thank HenryWichura for useful suggestions
and comments on an earlier version of the manuscript.
abstract: 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.
date: 2016-10
date_type: published
publication: Global and Planetary Change
volume: 145
publisher: Elsevier B.V.
pagerange: 30-41
id_number: 10.1016/j.gloplacha.2016.08.006
refereed: TRUE
issn: 09218181
official_url: http://dx.doi.org/10.1016/j.gloplacha.2016.08.006
related_url_url: https://scholar.google.co.in/scholar?q=Large+scale+pantelleritic+ash+flow+eruptions+during+the+Late+Miocene+in+central+Kenya+and+evidence+for+significant+environmental+impact&btnG=&hl=en&as_sdt=0%2C5
related_url_type: pub
citation:   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     
document_url: http://oar.icrisat.org/9770/1/Large%20scale%20pantelleritic%20ash%20flow.pdf