Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-27T12:17:17.388Z Has data issue: false hasContentIssue false
  • English
  • Français

Groundwater-Mediated Response to Holocene Climatic Change Recorded by the Diatom Stratigraphy of an Ethiopian Crater Lake

Published online by Cambridge University Press:  20 January 2017

Richard J. Telford  and
Henry F. Lamb
Richard J. Telford
Affiliation:
Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, SY23 3DB, United Kingdom
Henry F. Lamb
Affiliation:
Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, SY23 3DB, United Kingdom
Get access Rights & Permissions [Opens in a new window]

Abstract

The diatom stratigraphy of a 23-m sediment core from Lake Tilo, a maar lake in the Ethiopian Rift Valley, provides a 10,000-yr record of lake salinity and trophic status. Until 5500 14C yr B.P., the phytoplankton was dominated by Aulacoseira granulata, with only minor changes in the abundance of other diatoms; the lake was over 50 m deep, eutrophic, and oligosaline. At 5500 yr B.P., geothermal groundwater inflow, inferred from calcite and silica deposition rates, declined abruptly, and the lake became more oligotrophic, as indicated by a rapid rise in Cyclotella stelligera. About 4500 yr B.P., lake salinity began to increase, reaching approximately its present state ca. 2500 yr B.P., but with a temporary reversal to lower salinity at 4000–3500 yr B.P. The record shows no evidence of salinity increases equivalent to early Holocene low stands of the larger river-fed Rift Valley lakes, probably because of high rates of geothermal groundwater influx. It responded to reduced rainfall at 4500 yr B.P., when levels of the larger lakes also fell, because geothermal groundwater flux had diminished 1000 year earlier, independently of climate. Because geothermal groundwaters can form a significant proportion of a crater lake's hydrological budget and dominate its salinity budget, these results show that variable geothermal groundwater flux can override lake hydrochemical response to climate change. Palaeoclimatic interpretation of palaeosalinity proxies from the sediments of volcanic crater lakes should be approached with caution.

Keywords

diatomsEthiopiaHolocenepalaeolimnologycrater lakegroundwaterclimate change
Type
Research Article
Information
Quaternary Research , Volume 52 , Issue 1 , July 1999 , pp. 63 - 75
Copyright
University of Washington

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Aitken, M.J..(1990). Science-Based Dating in Archaeology. (1990).Google Scholar
Battarbee, R.W..(1986). Diatom analysis. Berglund, B.E.. Handbook of Holocene Palaeoecology and Palaeohydrology. (1986). Wiley and Sons, Chichester., 527–570.Google Scholar
Battarbee, R.W., Kneen, M.J..(1982). The use of electronically counted microspheres in absolute diatom analysis. Limnology and Oceanography. 27, (1982). 184–188.CrossRefGoogle Scholar
Dean, W.E..(1974). Determination of carbonate and organic matter in calcareous sediments and sedimentary rocks by loss on ignition: Comparison with other methods. Journal of Sedimentary Petrology. 44, (1974). 242–248.Google Scholar
Delibrias, G., Guillier, M.-T..(1988). GIF natural radiocarbon measurements XI. Radiocarbon. 30, (1988). 61–124.CrossRefGoogle Scholar
Di Paola, G.M..(1972). The Ethiopian Rift Valley (between 7°00′ and 8°40′ lat North). Bulletin Vulcanologique. 36, (1972). 517–560.CrossRefGoogle Scholar
Ethiopian Government, (1976). 1:50,000 series maps of Ethiopia: Ropi Sheet. Ministry of Lands and Settlement, Addis Ababa.Google Scholar
Fournier, R.O..(1986). The behavior of silica in hydrothermal solutions. Berger, B.R., Bethke, P.M.. Geology and Geochemistry of Epithermal Systems. (1986). Society of Economic Geologists, El Paso., 45–62.Google Scholar
Gasse, F..(1986). East African Diatoms Taxonomy, Ecological Distribution. (1986). Cramer, Berlin.Google Scholar
Gasse, F., Descourtieux, C..(1979). Diatomées et évolution de trois milieux Ethiopiens d'altitude différente, au cours du Quaternaire supérieur. Palaeoecology of Africa. 11, (1979). 117–134.Google Scholar
Gasse, F., Juggins, S., Khelifa, L.B..(1995). Diatom-based transfer functions for inferring past hydrochemical characteristics of African lakes. Palaeogeography, Palaeoclimatology, Palaeoecology. 117, (1995). 31–54.CrossRefGoogle Scholar
Gasse, F, Kroepelin, S, Oldfield, F. (1997). PEP III: The Pole–Equator–Pole transect through Europe and Africa. PAGES Workshop Report, Series 97–2.Google Scholar
Gasse, F., Street, F.A..(1978). Late Quaternary lake-level fluctuations and environments of the northern Rift Valley and Afar region (Ethiopia and Djibouti). Palaeogeography, Palaeoclimatology, Palaeoecology. 24, (1978). 279–325.CrossRefGoogle Scholar
Gasse, F., van Campo, E..(1994). Abrupt post-glacial climate events in west Asia and North Africa monsoon domains. Earth and Planetary Science Letters. 126, (1994). 435–456.CrossRefGoogle Scholar
Gell, P.A., Barker, P.A., De Decker, P., Last, W.M., Jelicic, L..(1994). The Holocene history of West Basin Lake, Victoria, Australia: Chemical changes based on fossil biota and sediment mineralogy. Journal of Paleolimnology. 12, (1994). 235–258.CrossRefGoogle Scholar
Gillespie, R., Street-Perrott, F.A., Switsur, R..(1983). Post-glacial arid episodes in Ethiopia have implications for climate prediction. Nature. 306, (1983). 680–683.CrossRefGoogle Scholar
Grimm, E.C..(1987). CONISS: A FORTRAN 77 program for stratigraphically constrained cluster analysis by the method of incremental sum of squares. Computers and Geosciences. 13, (1987). 13–35.CrossRefGoogle Scholar
Hall, R.I., Smol, J.P..(1992). A weighted-averaging regression and calibration model for inferring total phosphorous concentration from diatoms in British Columbian (Canada) lakes. Freshwater Biology. 27, (1992). 417–434.CrossRefGoogle Scholar
Hutchinson, G.E..(1967). A Treatise on Limnology. (1967). Wiley, New York.Google Scholar
Kilham, P., Kilham, S.S., Hecky, R.E..(1986). Hypothesized resource relationships among African planktonic diatoms. Limnology and Oceanography. 31, (1986). 1169–1181.CrossRefGoogle Scholar
Krammer, K., Lange-Bertalot, H..(1986). Band2/1: Bacillariophyceae. 1. Teil: Naviculaceae. Süßwasserflora von Mitteleuropa. (1986). Fischer, Stuttgart.Google Scholar
Krammer, K., Lange-Bertalot, H..(1988). Band2/2: Bacillariophyceae. 2. Teil: Bacillariaceae, Epithemiaceae, Surirellaceae. Süßwasserflora von Mitteleuropa. (1988). Fischer, Stuttgart.Google Scholar
Krammer, K., Lange-Bertalot, H..(1991). Band2/3: Bacillariophyceae. 1. Teil: Centrales, Fragilariaceae, Eunotiaceae. Süßwasserflora von Mitteleuropa. (1991). Fischer, Stuttgart.Google Scholar
Labeyrie, L.D., Juillet, A..(1982). Oxygen isotope exchangeability of diatom valve silica: Interpretation and consequences for palaeoclimatic studies. Geochimica et Cosmochimica Acta. 46, (1982). 967–975.CrossRefGoogle Scholar
Lorenz, V..(1986). On the growth of maars and diatremes and its relevance to the formation of tuff rings. Bulletin of Volcanology. 48, (1986). 265–274.CrossRefGoogle Scholar
Owen, R.B., Barthelme, J.W., Renaut, R.W., Vincens, A..(1982). Paleolimnology and archeology of Holocene deposits northeast of Lake Turkana, Kenya. Nature. 298, (1982). 523–529.CrossRefGoogle Scholar
Ricketts, R.D., Johnson, T.C..(1996). Climate-change in the Turkana basin as deduced from a 4000 year long δ18) record. Earth and Planetary Science Letters. 142, (1996). 7–17.CrossRefGoogle Scholar
Rind, D., Overpeck, J..(1993). Hypothesized causes of decade-to-century-scale climate variability—climate model results. Quaternary Science Reviews. 12, (1993). 357–374.CrossRefGoogle Scholar
Street, F. A. (1979). Late Quaternary lakes in the Ziway-Shala Basin, Southern Ethiopia. Unpublished Ph.D. dissertation, University of Cambridge.Google Scholar
Street-Perrott, F.A., Perrott, R.A..(1990). Abrupt climate fluctuations in the tropics: The influence of Atlantic Ocean circulation. Nature. 343, (1990). 607–611.CrossRefGoogle Scholar
Stuiver, M., Reimer, P.J..(1993). Extended 14C data base and revised CALIB 3.0 14C age calibration program. Radiocarbon. 35, (1993). 215–230.CrossRefGoogle Scholar
Tesfaye Chernet (1982). Hydrogeology of the Lakes Region. Ethiopia, Ministry of Mines and Energy, Addis Abeba.Google Scholar
United Nations, (1965). Report on Survey of the Awash River Basin. Imperial Ethiopian Government U. N. Special Fund Project. Addis Ababa.Google Scholar
Williams, M., Dunkerley, D., De Deckker, P., Kershaw, A., Chappell, J..(1998). Quaternary Environments. (1998). Arnold, London.Google Scholar
Wood, R.B., Baxter, R.M., Prosser, M.V..(1984). Seasonal and comparative aspects of chemical stratification in some tropical crater lakes, Ethiopia. Freshwater Biology. 14, (1984). 551–573.CrossRefGoogle Scholar
Wood, R.B., Prosser, M.V., Baxter, R.M..(1976). The seasonal pattern of thermal characteristics of four of the Bishoftu crater lakes, Ethiopia. Freshwater Biology. 6, (1976). 519–530.CrossRefGoogle Scholar
Wright, H.E., Mann, D.H., Glaser, P.H..(1983). Piston corers for lake and wetland sediments. Ecology. 65, (1983). 657–659.CrossRefGoogle Scholar