Late Cenozoic fluvial dynamics of the River Tana, Kenya, an uplift dominated record

Mount Kenya volcanic activity and the Late Cenozoic landscape reorganisation in the upper Tana fluvial system

http://www.stoorvogel.info/tradeoffs/download/2004%20Ellenkamp.pdf

SOIL VARIABILITY AND LANDSCAPE IN THE MACHAKOS DISTRICT KENYA . A detailed soil survey as part of the study on the influence of soil variability on the tradeoffs between agricultural production and soil fertility.

Quantifying soil carbon stocks and humification through spectroscopic methods: A scoping assessment in EMBU-Kenya

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.

/pdf/large-scale-pantelleritic-ash-flow-eruptions-during-the-late-xx0lm0i6ct.pdf

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

In Kenya, erosion surfaces up to now have been interpreted mainly using the cyclic denudation concept of King (1967), based on their specific altitudes. Detailed fieldwork in the Chuka-South area shows that altitudinal differences are more related to lithological control than to ages of planation surfaces. This strong lithology-landform relationship is thought to be caused by etching and stripping. Rock properties such as texture, mineralogy and the fracture porosity largely determine the rate of chemical decomposition. -from Authors

P.W. Visser

Papers

Erosion surfaces in the Chuka-South area, central Kenya