黄土细颗粒多矿物多片、单片光释光测年对比

Comparison of dating results between polymineralic fine-grains SAR and MAR

本文选择马兰黄土顶、底两个样品同时进行了细颗粒多片红外激发信号 (IRSL)和澳大利亚滑移法 (GLSL) ;单片IRSL、单片BLSL以及红外 (IRSL)后的蓝光 (post-IR)测年。测年结果表明 ,多测片滑移法更适合于黄土样品细颗粒的年龄测定 ,多测片滑移技术对细颗粒可测的年龄范围至少能达到 8万年。在各种细颗粒多矿物单片释光测年技术中 ,对于较老样品单片post-IR法测得的年龄与样品的实际年龄还有相当的差距 ,而对于较年轻样品 (全新世样品 ) ,单片的post-IR法测定的年龄与样品的实际年龄比较接近 。

A multiple-aliquot regeneration-dose (MAR) combining with 'Australian Slide method' and a single-aliquot regeneration-dose (SAR) protocol, involving stimulation of the same disc with an infra-red laser diode followed by blue LEDs, were applied to determine the equivalent dose (ED) of polymineralic fine-grains from loess samples collected from the top and the bottom of the Malan loess (L1) respectively. The multiple aliquot IRSL and GLSL, and single aliquot IRSL, BLSL and (post-IR) BLSL ages are presented for two fine grain (4-11 μm) fractions of the loess samples. The preliminary results show that the MAR protocol may be a perfect choice for luminescence dating of loess fine-grain samples, and can be employed to obtain an available age estimate for loess sample as older as approximately 80 ka BP., and that the age estimates obtained from the post-IR are closed to the independent age determinations for the younger (age less than 10 ka) fine grain samples. The ages from the post-IR, however, are much underestimated to those from independent method or expected estimates for the older samples. It may be suggest that the single-aliquot (post-IR) BLSL protocol of the fine grains could be a suitable choice to date the younger samples.