新疆昆仑山北坡黄土细颗粒混合矿物IRSL,[post-IR]OSL和细颗粒石英OSL测年初步研究  

PRELIMINARY STUDIES ON DATING USING IRSL AND[POST-IR]OSL SIGNALS FROM FINE-GRAINED POLYMINERALS AND OSL SIGNAL FROM FINE-GRAINED QUARTZ IN LOESS AT NORTHERN SLOPE OF KUNLUN MTS.,XINJIANG

作　　者：张克旗[1] 

机构地区：[1]中国地质科学院地质力学研究所,北京100081

出　　处：《第四纪研究》2012年第3期527-534,共8页Quaternary Sciences

基　　金：中国地质科学院地质力学研究所基本科研业务费项目(批准号:DZLXJK201109和DZLXJK200806)资助

摘　　要：使用感量校正多测片再生(SMAR)法对新疆昆仑山北坡的12个黄土样品的细颗粒混合矿物和细颗粒石英进行了等效剂量(D_e)的测量。测试结果显示,该地区黄土的[post-IR]OSL和OSL信号强度相对于黄土高原的样品偏低,初步认为与物源不同及粉尘堆积和堆积后经受的风化作用微弱有关。细颗粒混合矿物的IRSL等效剂量值基本上小于其细颗粒石英OSL的,反映出长石存在明显的异常衰减现象;[post-IR]OSL信号主要来自于长石,用于测年需谨慎;细颗粒石英OSL更适合用于对该地区黄土的测年。The equivalent doses of fine-grained polyminerals and OSL signal from fine-grained quartz were measured by using SMAR protocol to 12 loess samples from the northern slope of Kunlun Mts. ,Xinjiang. 8 of the 12 samples were collected from a loess section, which is 84m thick and located in a terrace, southwest of Aqiang township （36°23＇30＂N,81°54＇57＂E ;2670m a. s. 1. ）in Yutian County, and the other 4 samples were collected from terraces （36°15＇52＂-36°16＇35＂N,81°29＇28＂- 81°30＇35＂E;2100～2120m）at the west bank of the Keriya River. The results show that the intensities of [ post-IR ] OSL and OSL signals are lower than those of the loess samples from the Loess Plateau, which can be related preliminarily to the source differences between the two kinds of loess. It is also probable that the weak weathering of dust during accumulating and after accumulation make the intensity differences. These two factors resulted in the differences of the content and types of minerals between the two areas, as well as a different sensitivity of luminescence signals. The weak signals mean a low signal to noise ratio when a young sample is measured,which will make a low reliability of equivalent dose（Do）. The obvious anomalous fading of IRSL signals from feldspars was observed,thus it must be cautious to use the signal to date a sample,which will result in a fact that its De is less than the OSL De of fine-grained quartz. It must be cautious of dating the samples by using[ post-IR] OSL signals because they are mainly from the feldspar. It is more appropriate of dating the loess by using OSL signal of fine-grained quartz. The preliminary result shows that the optical dating has great potential for the study on chronology, dust accumulation rate, climate and environmental changes of the loess at northern slope of Kunlun Mts., Xinjiang.

关 键 词：OSL测年 SMAR法 黄土 昆仑山北坡 新疆 

分 类 号：P94[天文地球—自然地理学] P574