Vegetation changes in Empakaai Crater, northern Tanzania, at 14,800–9300 cal yr BP |
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Authors: | Maria A Ryner Raymonde Bonnefille Karin Holmgren Alfred Muzuka |
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Institution: | aDepartment of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm, Sweden bCentre Européen de Recherché et d' Enseignment des Geosciences de l'Environnement, CEREGE, Europôle Méditerrané de l´Arbois, BP 80, 13545 Aix en Provence Cedex 04, France cInstitute of Marine Science, University of Dar es Salaam, PO Box 668, Zanzibar, Tanzania |
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Abstract: | Vegetation changes are documented from a well-dated pollen record from Lake Emakat, Empakaai Crater, northern Tanzania. This pollen record includes the time interval covering the Pleistocene/Holocene transition, analysed at a resolution interval averaging 200 yr. Around the crater lake, an Hagenia-forest development starting at 14,500 cal yr BP lasted until 13,000 cal yr BP. A change in vegetation, indicated by an increased proportion of Nuxia congesta in the forest and Artemisia in the afro alpine grassland after 13,000 cal yr BP, corresponds in time to the Northern Hemisphere's Younger Dryas cooling. Grasses and sedges increased at 10,100 cal yr BP, indicating a significant increase in local pollen possibly attributed to lowered lake level, related to drier conditions. Although the Empakaai pollen record documents continuous forest conditions, from 14,500 to 10,100 cal yr BP, the variation in the proportion of forest components seem to respond to environmental changes at the millennium scale. |
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Keywords: | East Africa pollen analysis Pleistocene/Holocene transition vegetation change |
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