| 前处理步骤与方法对风成红粘土粒度测量的影响 |
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| 引用本文： | 鹿化煜,苗晓东,孙有斌.前处理步骤与方法对风成红粘土粒度测量的影响[J].海洋地质与第四纪地质,2002,22(3):129-135. |
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| 作者姓名： | 鹿化煜 苗晓东 孙有斌 |
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| 作者单位： | 中国科学院,地球环境研究所黄土与第四纪地质国家重点实验室,西安,710075 |
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| 基金项目： | 国家自然科学基金资助项目 (4 990 2 0 0 9)，中国科学院知识创新工程重大项目 (KZCX1-10 -0 1和 KZCX2 -SW-118) |
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| 摘 要： | 中国北方晚第三纪红粘土堆积为研究古气候与古环境提供了很好的地质记录，其粒度测量作为一个重要的代用指标被广泛应用。粒度测量结果受到前处理方法的影响，但是，现在各个实验室的前处理方法还不一致，这就为粒度数据分析和古气候古环境解释带来了困难。在黄土高原从北到南选择了3个具有代表性的红粘土剖面，对每个剖面从下向上取10块样品总计得到30块样品，对每个样品用不同的前处理方法与步骤（包括化学分离石英的方法）处理后用激光粒度仪进行颗粒测量。结果表明，前处理方法与步骤可以使同一个样品粒度参数发生几倍甚至于二十几倍的变化。综合理论和经验分析，推荐了一种较好的进行风尘堆积粒度测量的前处理方法（正文中方法C）。化学分离的纯石英的粒度分布比本文推荐的方法处理同一个样品的粒度结果偏粗，表明在提纯石英的过程中较细的不稳定矿物已经被剔除。
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| 关 键 词： | 红粘土 粒度测量 前处理方法 风尘堆积 古气候 古环境 第三纪 |
| 文章编号： | 0256-1492(2002)03-0129-07 |
| 修稿时间： | 2001年10月24 |
PRETREATMENT METHODS AND THEIR INFLUENCES ON GRAIN-SIZE MEASUREMENT OF AEOLIAN "RED CLAY" IN NORTH CHINA |
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| LU Hua yu,MIAO Xiao dong,SUN You bin.PRETREATMENT METHODS AND THEIR INFLUENCES ON GRAIN-SIZE MEASUREMENT OF AEOLIAN "RED CLAY" IN NORTH CHINA[J].Marine Geology & Quaternary Geology,2002,22(3):129-135. |
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| Authors: | LU Hua yu MIAO Xiao dong SUN You bin |
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| Abstract: | The "Red Clay",which is underlying Quaternary loess paleosol deposit,is regarded as a good proxy record of climate and environment changes in late Miocene and Pliocene in North China.And,its grain size distribution is widely employed to reconstruct palaeoclimate as well as palaeoenvironment.However,pretreated methods for the grain size measurement are various in laboratories,the pretreated procedures have certainly influenced results of grain size distribution,and therefore cause controversy over the palaeoclimatic and palaeoenvironmental interpretations.Here,we choose 30 "Red Clay" samples from three representative sections which are located at a transaction from north to south in the Loess Plateau,and each sample is pretreated in six different ways and the samples are measured in a laser particle analyzer.Results show that there exist great differences in grain size distribution of one sample pretreated in the ways:differences of the size index such as Mean can be 20 times fluctuation.We meanwhile examine influences of each step on the grain size measurement,and a pretreatment method is strongly recommended.By this method,the calcium carbonate,organic matter and part of the secondary ferruginous mineral are removed,and the chemical dispersion matter((NaPO 3) 6)as well as the ultrasonic machine are employed in order to completely disperse the particles.We also prove that chemically extracted quartz from the "Red Clay" is coarser in grain size than that of the bulk samples.This results from the removing of the secondary minerals.This may bring further question if the chemically extracted quartz is a good proxy index although it is insensitive to weathering after deposit. |
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| Keywords: | red clay grain size analysis pretreated methods aeolian deposit in North China |
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