Tracking the hydro-climatic signal from lake to sediment: A field study from central Turkey

JOURNAL OF HYDROLOGY

卷:529

Article

Dean, Jonathan R.¹  Eastwood, Warren J.²  Roberts, Neil³  Jones, Matthew D.⁴  Yigitbasioglu, Hakan⁵  Allcock, Samantha L.⁶  Woodbridge, Jessie³  Metcalfe, Sarah E.⁴  Leng, Melanie J.^1,7 

[1] British Geol Survey, NERC Isotope Geosci Facil, Nottingham NG12 5GG, England

[2] Univ Birmingham, Sch Geog Earth & Environm Sci, Birmingham B15 2TT, W Midlands, England

[3] Univ Plymouth, Sch Geog Earth & Environm Sci, Plymouth PL4 8AA, Devon, England

[4] Univ Nottingham, Sch Geog, Nottingham NG7 2RD, England

[5] Ankara Univ, Dept Geog, TR-06100 Ankara, Turkey

[6] Bournemouth Univ, Fac Sci & Technol, Poole BH12 5BB, Dorset, England

[7] Univ Nottingham, Sch Geog, Ctr Environm Geochem, Nottingham NG7 2RD, England

关键词: Oxygen isotopes;    Diatom analysis;    Lake sediments;    Monitoring;    Seasonality;    Carbonates;   

DOI  :  10.1016/j.jhydrol.2014.11.004

来源: Elsevier

【 摘 要 】

Palaeo-hydrological interpretations of lake sediment proxies can benefit from a robust understanding of the modern lake environment. In this study, we use Nar Golu, a non-outlet, monomictic maar lake in central Turkey, as a field site for a natural experiment using observations and measurements over a 17-year monitoring period (1997-2014). We compare lake water and sediment trap data to isotopic, chemical and biotic proxies preserved in its varved sediments. Nar Golu underwent a 3 m lake-level fall between 2000 and 2010. delta O-18(lakewater) is correlated with this lake-level fall, responding to the change in water balance. Endogenic carbonate is shown to precipitate in isotopic equilibrium with lake water and there is a strong relationship between delta O-18(lakewater) and delta O-18(carbonare), which suggests the water balance signal is accurately recorded in the sediment isotope record. Over the same period, sedimentary diatom assemblages also responded, and conductivity inferred from diatoms showed a rise. Shifts in carbonate mineralogy and elemental chemistry in the sediment record through this decade were also recorded. Intra-annual changes in delta O-18(lakewater) and lake water chemistry are used to demonstrate the seasonal variability of the system and the influence this may have on the interpretation of delta O-18(carbonate) We use these relationships to help interpret the sedimentary record of changing lake hydrology over the last 1725 years. Nar Golu has provided an opportunity to test critically the chain of connection from present to past, and its sedimentary record offers an archive of decadal- to centennial-scale hydro-climatic change. (C) 2014 Elsevier B.V. All rights reserved.

【 授权许可】

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