A proposal of new isotope geothermometer from lake sediments

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The past climate change is recorded on lake sediments. However, the records obtained from the lake sediments are subject to the influence of two or more environmental factors. The data interpretation is not easy task. In this research, a new approach was proposed and examined for quantitative reconstruction of lake water temperature. The isotope thermometer are based on the premise that aquatic celluloseδ^<18> O serves as a direct proxy for lake waterδ^<18> O, thereby allowing resolution of temperature signals inδ^<18> O records from co-existing diatom silica frustules which are influenced by lake water temperature and lake waterδ^<18> O The diatom. cellulose isotope-thermometer was applied to the sediments from Lake Biwa(central Japan) and a marr lake in Inner Mongolia on a trial basis. Although our current data set cannot support more accurate scaling of developed isotope-thermometers, the difference in the presumed temperature was in agreement with the growth season temperature difference of two areas. It was confirmed that this novel multi-isotope approach clearly has much to offer the information of climate changes in continental environments.