SIGNIFICANCE OF LAKE SEDIMENT COLOR FOR SHORT TIME SCALE CLIMATE VARIATION
Received date: 2003-06-30
Revised date: 2003-11-07
Online published: 2004-10-01
Deap-sea sediment-color record from Atlantic has been widely used to reconstruct climate variation on millennial time scales. Can lake sediment color be used to reflect climate change in shorter timescale? In this paper we have discussed it based on statistical correlation between L*, a*, b* (CIE/L*a*b* color system) and some geochemical proxies. L* (brightness) is positive correlated with carbonate content, and higher L* value corresponds to higher carbonate content and cold and dry climate, and vice versa. a* value (red-green color) is correlated with Mg content in sediments. Higher a* value corresponds to higher MgO content in sediments and higher Mg/Ca ratio of sediments which reflect warmer climate. b* value is positively correlated with Fe3+ content. Higher b* value represents sediments formed in oxidation condition, and b* value can indirectly reflect lake water depth change and efficient moisture change. To sediments of Gourenco Lake, the curve of a* value is mirrored with that of b* which reflects the climatic combination of cold and dry or warm and wet in this area. Based on the significance of lake sediment color in Gourenco Lake, the climate change in this area can be deduced since 1400 AD. Since 1400 AD, climate in this area has undergone several times of fluctuations. The Little Ice Age began from 1430 AD and ended at 1890 AD. Climate change in recent 40 years is coincided with instrument record of nearby meteorological stations.
Key words： Lake sediment; Color; Paleoclimate; Tibetan plateau; Gourenco Lake.
WU Yan-hong, LI Shi-jie . SIGNIFICANCE OF LAKE SEDIMENT COLOR FOR SHORT TIME SCALE CLIMATE VARIATION[J]. Advances in Earth Science, 2004 , 19(5) : 789 -792 . DOI: 10.11867/j.issn.1001-8166.2004.05.0789
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