Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Siliceous microfossils as Late Quaternary paleo-environmental indicators at Braamhoek wetland, South Africa
Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
2010 (English)In: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 20, no 5, 747-760 p.Article in journal (Refereed) Published
Abstract [en]

A peat-sequence covering the last 16 ka (16 000 cal. yr BP) from Braamhoek wetland, eastern South Africa, was analysed in terms of phytolith and diatom composition. The fossil peat was rich in phytoliths, while diatoms were less prominent, probably as a result of degradation during wetland plant growth associated with silica uptake. With this study we present the first continuous phytolith and diatom record from South Africa covering the Late Pleistocene and Holocene period. The phytolith assemblages indicate a clear dominance of C

3-grasses within the wetland throughout the sequence. The fossil diatom record infer changes in past moisture conditions. Unlike the modern wetland, which is dominated by benthic and aerophilic diatoms, the Late Pleistocene– early Holocene wetland favoured growth of planktonic species. Abundance of planktonic diatoms suggests three main phases when water depth was deeper than today; at c.13.6 ka, 11.3 ka and 10.4–10.0 ka. These indications of past fluctuations in humidity mostly provide confirmation of previously published indications of pollen, charcoal fragments and isotopes in the same core, but the siliceous microfossil data also help to refine the paleo-environmental interpretation of the sequence.

Place, publisher, year, edition, pages
2010. Vol. 20, no 5, 747-760 p.
Keyword [en]
diatoms, Holocene, paleoclimate, phytoliths, South Africa
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:su:diva-24706DOI: 10.1177/0959683610362810OAI: oai:DiVA.org:su-24706DiVA: diva2:198148
Note
Part of urn:nbn:se:su:diva-7375Available from: 2008-02-25 Created: 2008-02-15 Last updated: 2017-12-13Bibliographically approved
In thesis
1. Late Quaternary climate and environmental change in the summer rainfall region of South Africa: A study using trees and wetland peat cores as natural archives
Open this publication in new window or tab >>Late Quaternary climate and environmental change in the summer rainfall region of South Africa: A study using trees and wetland peat cores as natural archives
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis contributes with information on past climate and environmental changes in South Africa’s summer rainfall region. The study is based on multi-proxy analyses on wetland peat cores and analyses of stable isotope composition (δ13C, δ18O) and wood anatomy in cross sections from subtropical trees (Breonadia salicina). The peat archive covers the last 16 ka (ka; 1000 cal yrs BP) and was analysed in terms of fossil pollen, charcoal, diatoms, phytoliths and stable isotope composition. The peat record infers relatively wet climate conditions at c. 13.7-12.8 ka, 10.5-9.5 ka and 2.5-0.5 ka, and drier conditions at c. 16-13.7 ka, 12.8-10.5 ka and during mid-Holocene. Tentatively, cooler late Pleistocene temperatures shifted towards warmer after c. 9.5 ka. The study of B. salicina demonstrates the paleo-climatic value of subtropical trees despite absence of annual tree rings. An age model was constructed from radiocarbon dating and calibration by wiggle matching. δ13C in B. salicina shows a co-variation with annual rainfall amounts, suggesting that it may be considered a regional climate-proxy. δ18O is mainly influenced by local factors, but acts as a useful complement when interpreting δ13C. Together with other regional, high-resolution records, the 600 year long δ13C-record suggests dry climate conditions in northern South Africa during the 1700s and mid-1500s AD. Inferred climate and environmental changes are suggested being a response to expansion, contraction and latitudinal shifts of the tropical, subtropical and mid-latitude atmospheric circulation cells. An observed inverse humidity pattern between southern and equatorial Africa suggests that ENSO-like teleconnections may be a possible forcing mechanism in a decadal to centennial time perspective.

Place, publisher, year, edition, pages
Stockholm: Institutionen för naturgeografi och kvartärgeologi, 2008. 108 p.
Series
Dissertations from the Department of Physical Geography and Quaternary Geology, ISSN 1653-7211 ; 11
Keyword
paleoclimate, Late Quaternary, pollen, stable isotopes, diatoms, phytoliths, dendroclimatology, South Africa
National Category
Physical Geography
Research subject
Physical Geography
Identifiers
urn:nbn:se:su:diva-7375 (URN)978-91-7155-581-6 (ISBN)
Public defence
2008-03-17, De Geersalen, Geovetenskapens hus, Svante Arrhenius väg 8 A, Stockholm, 13:00
Opponent
Supervisors
Available from: 2008-02-25 Created: 2008-02-15Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Finné, MartinNorström, ElinRisberg, Jan
By organisation
Department of Physical Geography and Quaternary Geology (INK)
In the same journal
The Holocene
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 90 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf