察尔汗地区130ka B.P.以来湖相沉积物颜色记录的气候变化探讨

Climatic Change Recorded by the Chroma of Lacustrine Sediments from 130 ka B.P.in Qarhan Area

通过柴达木盆地察尔汗地区湖相沉积物的L*、a*和b*值与有关地球化学指标的相关关系分析,对湖相沉积物颜色指标在古气候研究中的意义进行了探讨,并据此分析了130 ka B.P.以来该区的古气候演变过程。结果表明,L*值与沉积物碳酸盐含量正相关,L*值高时,气候冷干,碳酸盐含量较高;反之,气温上升,湿度增加。b*值和a*值与沉积物中Fe、Mg含量相关,高a*值反映气温较高,b*值可用于反映湖水深度变化和有效湿度的变化,b*值高,湖水浅,氧化作用增强。察尔汗地区色度曲线反映的气候变化特征与其他的气候指标曲线相吻合。

The search, then th present paper discusses the meaning of lacustrine sediments chroma to paleoclimate re- e paleoclimate change since 130 ka B. P. in Qarhan area was analyzed through the corre- /ation ship between L＊, a ＊ and b＊ of lacustrine sediments with other geochemical indexes. The result shows that it is correlation between L＊ and carbonate, L＊ is high when the environment is cold, dry and the content of carbonate is high also, while the L＊ is low when environment is warm and humid. Besides, it is correlation between a＊ , b＊ and the content of Mg and Fe in sediments, it means warm when a＊ is high, b＊ response to the depth of lake and humid, b ＊ is high when lake is shallow and strong oxidation. The curve of chrome is consistent with other paleoclimate indexes curve.