Recent eruptive episodes of the Rungwe volcanic field (Tanzania) recorded in lacustrine sediments of the Northern malawi rift

T. M. Williams*, P. J. Henney, R Bernhart OWEN

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Discrete ash horizons in Holocene sediments from northern Lake Malawi provide evidence of six eruptive episodes within the nearby Rungwe Volcanic Field between c.9000-360 BP. Rare earth element (REE) analyses show the ash layers to be strongly enriched in La, Ce, Pr, Nd, Sm, Tb, Dy, Er, Tm, Yb and Lu, with low Eu/Eu* and high LaN/SmN values, relative to the surrounding muds. Mixing calculations suggest possible affinities between the Rungwe ash emissions and silicic volcanics from other important Quaternary centres (e.g. Naivasha) with respect to HREE geochemistry. The LREE spectra are less comparable and may indicate a less fractionated ash assemblage for Rungwe Field. In the absence of clear in situ evidence regarding the timing and frequency of Holocene eruptions at Rungwe, the Lake Malawi sediments may prove a valuable reconstructive tool. However, the direction and extent of ash dispersal is strongly controlled by wind/climatic factors and the retention of a complete record at any single location is unlikely.

Original languageEnglish
Pages (from-to)33-39
Number of pages7
JournalJournal of African Earth Sciences
Volume17
Issue number1
DOIs
Publication statusPublished - Jul 1993

Scopus Subject Areas

  • Geology
  • Earth-Surface Processes

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