Paleohydrology and paleoclimate records in a saline prairie lake core: mineral, isotope and organic indicators

• Published in: Journal of paleolimnology 1993-01, Vol.8 (2), p.135-147
• Main Authors: Van Stempvoort, D. R., Edwards, T. W. D., Evans, M. S., Last, W. M.
• Format: Article
• Language: English
• Subjects: Brackish
• ISSN: 0921-2728; 1573-0417
• DOI: 10.1007/BF00119786

This pilot study examines the potential of obtaining a sedimentary record of paleoenvironmental/climatic/hydrology conditions for saline Redberry Lake in southern Saskatchewan, Canada. The tools are mineralogy, stable isotopes and pigments. The upper meter of an offshore sediment core contains 10 to 20% by weight aragonite (CaCO sub(3)), which apparently precipitated in the water column. The delta super(18)O and delta super(13)C of the bulk aragonite (corrected for content of detrital calcite) vary by 4 to 5 ppt. Enrichment in super(18)O in aragonite is significantly correlated with pigment concentrations (chlorophyll a, phaeophytin). The delta super(18)O and pigment data provide evidence for relatively dry and/or warm conditions and high limnetic productivity for the period 2500 to 1500 yrs B.P. After 1500 B.P., the climate was apparently similar to the present, with two episodes of relatively enhanced productivity, dryness and/or warmth, at around 1000 to 900 and 500 to 200 B.P. During the past century, Redberry Lake has decreased approximately 8 m in depth and its salinity has doubled. No clear sedimentary signal was observed in response to these recent hydrologic trends. These changes have not been associated with a significant climate trend in the region, but may have been induced by land use changes in the catchment.