用改进的单片再生剂量法测定多矿物细粒黄土的等效剂量

应用单片再生剂量法对陕西关中的全新世黄土进行细颗粒蓝光释光、红外释光和红外之后的蓝光释光的等效剂量De测定，在实验中用一固定的实验剂量（Dt≈(10%-20%)De)的释光信号来校正灵敏度的变化。在这3种释光信号中，红外之后的蓝光释光信号较为稳定，其De值较接近预测值。说明预先红外暴露去除了低能量的陷阳电子，剩下了稳定的高能量陷阱电子。     

灞河泥沙的形成条件及沉积特征

灞河古称滋水,发源于秦岭北坡,是渭河南岸较大支流之一,流域面积约2577平方公里,河长92.6公里,平均比降5.98％.在河流的中下游,右岸支流众多,左岸稀少,成为不对称水系. 灞河年径流与该区降水和蒸发关系甚为密切,降水的多少是径流变化的决定因素.由于降水年内分配不均,河流年径流具有明显的季节变化,夏季为丰水期,冬季为枯水     

淮河上游全新世黄土及沉积成因

The dust source and transporting system are two indispensable aspects in the process of loess-palaeosol accumulation. It has been proved that the dust of the Loess Pla-teau mainly comes from the northwestern inland gobi and desert, transported by the East Asia monsoon systems and westerlies. However, there are little researches with respect to the dust source and deposition dynamics of the upper reaches of the Huaihe River. In the present study, we investigated and collected the YPC section with high resolution in the upper reaches of the Huaihe River. The chronological frame was reconstructed by optically stimu-lated luminescence(OSL)dating and correlated with the published loess time series. By comparison of the magnetic susceptibility(MS)and grain size(GS)of loess-soil profile among YPC profile, XJN profile(western Loess Plateau)and the JYC profile(southern Loess Pla-teau), we find sirnilar climate change and pedogenic process between the upper reaches of the Huaihe River and the Loess Plateau, both experienced an extreme dry and the weakest pedogenesis during the last glacial, followed by a transitional episodes from the cold-dry last glacial to the warm-humid mid-Holocene and increased pedogenesis in the early Holocene,then a most humid-warm and strong pedogenesis in the mid-Holocene, and climate deterio-ration and decreased pedogenesis occurred during the late Holocene. But the MS of loess-soil profile sequences in the upper reaches of the Huaihe River was much lower than those in the Loess Plateau, and the GS was much coarser than those in the Loess Plateau.Comparison of GS for these three profiles revealed that there were different dust sources,which belonged to different aeolian transporting systems. The loess in the upper reaches of the Huaihe River was a wind blown deposition of near source, while the coarser dust mainly came from loose alluvial deposits of alluvial and proluvial fans of the Yellow River. The yield-ing and carrying dynamics of the dust in the Huaihe River is the northeast wind prevails in the winter half year.     

单片再生剂量法测定全新世黄土等效剂量预热条件的研究

本文通过对双程序单片再生剂量法(Double-SAR)即同时测红外释光(IRSL)和红外之后的蓝光释光(Post-IR OSL)中普遍采用的几种预热温度和cut-heat温度进行了不同组合,然后测定了全新世黄土样品的等效剂量.测定结果表明:等效剂量对预热温度有一定程度的依赖性,而对cut-heat温度的依赖性显得更加明显,一般随cut-heat温度的升高而增大;同时在200-300 ℃的预热温度范围内,200-240 ℃的cut-heat温度下测定的等效剂量出现了一个显著坪区,且红外释光和红外之后的蓝光释光测得的结果最为接近.红外释光和红外之后的蓝光释光在以上预热温度和cut-heat温度条件下光释光信号的感量变化方向一致、变幅较小可能是测得的等效剂量较为一致的主要原因.这说明在200-300 ℃的预热温度范围内,200-240 ℃的cut-heat温度对于测定年轻的全新世黄土样品是较为可靠的.     

High TOCⅡ分析仪快速测定土壤和黄土样品中的有机碳

利用High TOCⅡ分析仪测量了土壤和黄土样品中有机碳的含量，通过与重铬酸钾氧化法和微波消化法测量结果的比较发现，3种方法的分析结果无明显差异，测量结果是仪器法好于微波消化法，微波消化法好于重铬酸钾氧化法，仪器法具有操作过程简单，样品用量少，分析结果误差小，分析快速和测量结果准确等特点。     

单片再生剂量法测定全新世黄土等效剂量预热条件研究

释光测年在等效剂量测定过程中都会对测年样品进行热处理,其中预热是最为主要的热处理过程,但由于随之产生的热迁移和热激活等问题,使得预热处理及其条件的设置是应用释光准确测年的关键之一.本文主要是将目前常规测年中应用的双程序单片再生释光法的红外释光(IRSL)和红外之后的蓝光释光(Post-IR OSL)中的几种预热温度和实验剂量后的CUt-·heat温度进行不同组合,然后进行了若干黄土样品等效剂量的测定.测定结果表明:等效剂量表现了对预热温度一定程度的依赖性,尤其是对实验剂量后cut-heat温度的依赖性更加明显,一般随cut-heat温度的升高而增大;在200-300℃预热温度范围内,200-240℃的cut-heat温度下测定的等效剂量出现了一个坪区,且红外释光和红外之后的蓝光释光测得的结果最为接近.二者在以上预热温度范围内在200-240℃的cut-heat温度条件下释光信号的感量变化方向一致、变幅较小可能是两种释光条件下测定的等效剂量较为一致的主要原因,而这种感量变化在整个测定过程中没有被完全校正又导致了等效剂量随cut-heat温度的变化.     

豫中黄土地区全新世土壤剖面成壤环境变化研究

通过对河南新郑黄土-土壤剖面的野外考察及室内的磁化率、烧失量、碳酸钙及粒度分析研究,认为:豫西山地山前丘陵台地的完整黄土-土壤剖面,是在气候波动变化的条件下形成的.全新世气候的变化,导致了以风尘堆积为主的成黄土期与以风化成壤作用为主的成壤期互相更迭.在全新世早期,风尘堆积旺盛,形成了过渡性黄土层(L1),在8500aB.P.～3100aB.P.的全新世大暖期,发育了浊红棕色古土壤(S0).这一时期降水丰沛,土壤水分充足,导致了古土壤层(S0)及其以下的过渡层(Lt)、马兰黄土层(L1)顶部都受到了明显的淋溶作用影响,而完伞脱钙.3100a B.P.之后,气候恶化,沙尘暴活动显著增强,加之黄河下游人类活动影响不断加剧,黄泛平原风沙活动十分强烈,风尘堆积形成了沙质黄土(L0).1500aB.P.以来,近代黄土持续堆积,由于气候的转嗳与人类农业耕作影响在持续堆积的近代黄土L0表层形成了现代土壤(TS).