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The Mg/Sr ratio in a stalagmite, which is di-rectly proportional to DMg/Ca, the solid-liquid distribution coefficient of Mg, is proposed as a geochemical thermometer to estimate paleotemperature changes. The paleotempera-ture change in eastern Beijing over the past 3000 years has been reconstructed by using this thermometer in the stalag-mite ZFFS-1 from Jingdong Cave. The records can be di-vided into two periods: 3000—2000 aBP, cool and wet, the air temperature averaging 9.8℃; and 2000 aBP—present, hot and dry, the air temperature being 1℃ higher than the mean value (11.7℃) of the past 3000 years. During 500—200 aBP, the air temperature was about 1.2℃ lower than that of the present, corresponding to the Little Ice Age in Europe. Like d 18O and d 13C, Mg/Sr (or DMg/Ca) reflects an obviously warming trend of the past 200 years. These results are sup-ported by historic records.
The Mg / Sr ratio in a stalagmite, which is di-rectly proportional to DMg / Ca, the solid-liquid distribution coefficient of Mg, is proposed as a geochemical thermometer to estimate paleotemperature changes. The paleotempera-ture change in eastern Beijing over the past 3000 years has been reconstructed by using this thermometer in the stalag-mite ZFFS-1 from Jingdong Cave. The records can be di-vided into two periods: 3000-2000 aBP, cool and wet, the air temperature averaging 9.8 ° C; and 2000 aBP-present, hot and dry, the air temperature being 1 ° C higher than the mean value (11.7 ° C) of the past 3000 years. During 500-200 aBP, the air temperature was about 1.2 ° C lower than that of the present, Like d 18O and d 13C, Mg / Sr (or DMg / Ca) reflects an obviously warming trend of the past 200 years. These results are sup-ported by historic records.