风成沉积物红外及绿光释光测年比较研究

COMPARISON OF IRSL AND GLSL DATING OF AEOLIAN SEDIMENTS

中国沙漠黄土边界带是地质时期东亚季风气候变化的敏感地带 ,其风成沉积物记录了东亚季风气候的变迁。对处于沙漠黄土边界带的吉林省太平川剖面进行了钾长石红外释光及石英绿光释光测年的比较研究 ,详细阐述了粗颗粒技术样品的前处理方法及钾长石和石英单矿物的分离过程 ,对于预热而导致的热转移信号对光释光测年中等效剂量的影响作了探讨 。

The advantage of Optical Stimulated Luminescence (OSL) dating over thermoluminescence dating is that the OSL signal can be bleached to nearly zero level in natural sun light within minutes.Aeolian sediments in loess/desert transitional zone in China provide records of climatic and monsoonal changes in the region.Infrared Stimulated Luminescence (IRSL)and Green Light Stimulated Luminescence(GLSL)dating using 125—150μm potassium rich feldspar and quartz minerals separated from six samples gave concordant results: (1)Of the same sample,IRSL and GLSL ages are nearly the same,but from the whole trend,IRSL ages are smaller than GLSL ones,which is more evident with the increase of the age values,perhaps resulting from mid term decay of IRSL signal (2)Thermal transfer due to preheat has made little contribution to both IRSL and GLSL signals,meaning that the influence of thermal transfer on dating samples more than 1 ka older is too small to be taken into account (3)GLSL dating can give good GLSL ED plateau of CHN 1Q through late light subtraction technique (4)High stimulation temperature can give high IRSL ED