柴达木盆地东北部中新世沉积物色度记录的气候变化

CLIMATE CHANGES RECORDED BY COLORS OF THE MIOCENE SEDIMENTS IN NORTHEAST QAIDAM BASIN

中新世是新生代古气候变化的关键时期。本文以柴达木盆地东北部瑙格剖面18.4～6.9Ma沉积物为研究对象,通过对沉积物颜色指标的测定与分析,获得该时段沉积物高分辨率颜色指标变化序列。发现色度值变化与氧化—还原作用有关,红度值与赤铁矿相对含量呈正相关。结合其它资料分析表明,柴达木盆地东北部地区中新世气候变化为18.4～14.2Ma相对暖湿阶段、14.2～7.7Ma相对冷湿阶段、7.7～6.9Ma相对干冷阶段,其变化可能受到全球温度变化的影响,气候转型主要导致了该区沉积相和沉积物色度的变化。

The Miocene is the key period for studying the Cenozoic climate changes.The sediment of Naoge section located in the northeast Qaidam Basin could record Climate changes from ～18.4 to 6.9Ma.Based on the measurement and the analysis of the color of the sidement,we got the high resolution changes of the color during this period.The change of the color is related to the Oxidation-reduction reactions,the redness and the hematite is positively correlated.The Climate change of this area from 18.4 to 6.9 Ma can be identified the following stages： the warm and humid period（18.4～14.2Ma）,the cold and humid period（14.2～7.7Ma）,the cold and dry period（7.7～6.9Ma）,the global temperature maybe caused this change and the climate transformation leads to the changes of the sedimentary facies and the color values.