Radiocarbon analysis of halophilic microbial lipids from an Australian salt lake

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• 作者：P. Sargent Bray^a ; ^{sarge.bray@mq.edu.au} ; Claudia M. Jones^b ; Stewart J. Fallon^c ; Jochen J. Brocks^c ; Simon C. George^a
• 关键词：Hypersaline ; Radiocarbon ; Biomarker ; Lake Tyrrell ; Dating ; Geochemistry
• 刊名：Quaternary Research
• 出版年：2012
• 出版时间：January 2012
• 年：2012
• 卷：77
• 期：1
• 页码：104-109
• 全文大小：1038 K

文摘

Assigning accurate dates to hypersaline sediments opens important terrestrial records of local and regional paleoecologies and paleoclimatology. However, as of yet no conventional method of dating hypersaline systems has been widely adopted. Biomarker, mineralogical, and radiocarbon analyses of sediments and organic extracts from a shallow (13 cm) core from a hypersaline playa, Lake Tyrrell, southeastern Australia, produce a coherent age-depth curve beginning with modern microbial mats and extending to ~ 7500 cal yr BP. These analyses are furthermore used to identify and constrain the timing of the most recent change in hydrological regime at Lake Tyrrell, a shift from a clay deposit to the precipitation of evaporitic sands occurring at some time between ~ 4500 and 7000 yr. These analyses show the potential for widespread dating of hypersaline systems integrating the biomarker approach, reinforce the value of the radiocarbon content of biomarkers in understanding the flow of carbon in modern ecologies, and validate the temporal dimension of data provided by biomarkers when dating late Quaternary sediments.