Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

Record number 424579
Title Mount Kenya volcanic activity and the Late Cenozoic landscape reorganisation in the upper Tana fluvial system
Author(s) Veldkamp, A.; Schoorl, J.M.; Wijbrans, J.R.; Claessens, L.F.G.
Source Geomorphology 145-146 (2012). - ISSN 0169-555X - p. 19 - 31.
DOI https://doi.org/10.1016/j.geomorph.2011.10.026
Department(s) Land Dynamics
PE&RC
Publication type Refereed Article in a scientific journal
Publication year 2012
Keyword(s) african climate-change - western turkey - sediment yield - gregory rift - debris flows - east-africa - pleistocene - evolution - river - uplift
Abstract Volcanic–fluvial landscape interaction of the late Cenozoic Mt Kenya region in the upper Tana catchment has been reconstructed. The oldest newly dated phonolite flow is 5.78 Ma (40Ar/39Ar), placing the initiation of Mt Kenya volcanic activity within the Late Miocene, much earlier than reported before, 3–3.5 Ma (K/Ar). The main body of the stratovolcano was already in existence around 4.22–5.27 Ma (40Ar/39Ar) supplying lahars to its lower footslopes. The final recorded volcanic main vent phase in the study area produced multiple phonolitic flows and lahars around 2.8 Ma (40Ar/39Ar). There is evidence of at least two major Pliocene drainage blocking events between 3.89 and 2.81 Ma (40Ar/39Ar) causing lava dammed lakes in which volcanic tuff deposits accumulated. Around this time the river Tana did not incise much and shaped an extensive fluvial plain, whose remnants can now be found around 1150 m altitude. This fluvial plain has been incising during the last 2.8 Ma, whereby the incision rate changed in time due to changing uplift rate and volcanic events. A flood basalt eruption covering 1150 km2, estimated to be 5 km3, on the south flank of Mt Kenya of the Thiba basalts at 0.80 Ma (40Ar/39Ar) plugged the Upper Tana basin and caused significant drainage reorganisation. The Tana was diverted southwards abandoning its former valley. The terrace record in the Tana valley downstream the Thiba basalts appears to register this event as a post 0.8 Ma accelerated incision. Current Thiba valley morphology is relatively young and appears to register uplift controlled terraces with interbedded lahars for the last 300 ka only, indicating a delayed fluvial response of approximately 0.5 Ma. The landscape reconstruction demonstrates that the Tana was well able to compensate for many volcanic events such as lahars and lava flows. Only the build-up of a stratovolcano body and a large flood basalt caused prolonged impact on fluvial landscape development
Comments
There are no comments yet. You can post the first one!
Post a comment
 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.