The upper 200 cm of a 7.2 m long sediment core from Lake Mirabad, Iran, were examined for oxygen and carbon isotope values, trace-elements and carbon nitrogen ratios in order to create a climate record for the last 1500 years. The chronology (A.D. 566-1943) was established using AMS dating. Evaporative enrichment was secondary to atmospheric vapor exchange and/or seasonality of precipitation as a forcing mechanism on δ18O ratios throughout most of this period. Temperatures and effective moisture increased during the Medieval Climate Anomaly. The Spörer Minimum, at the beginning of the Little Ice Age (LIA), brought lower temperatures and a decrease in effective moisture which continued throughout the LIA, resembling climatic conditions during the last glacial maximum. The Maunder Minimum, at the end of the LIA, was accompanied by shifts in the seasonality of precipitation. Evaporative enrichment became the dominant forcing mechanism from A.D. 1850 onward as lake levels increased.
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 49/04M, Masters Abstracts International|
|Subjects:||Paleoclimate Science, Geochemistry|
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