聚氨酯泡塑富集硫脲解脱-石墨炉原子吸收光谱法测定地质样品中金铂

泡沫塑料常用于富集常规地质样品中的铂族元素,而富集后往往用高温灰化法解脱,此法操作繁琐,温度过高易使铂配合物分解为王水难以提取的不溶性残渣,导致测试结果不稳定、效率低;单独使用20 g/L硫脲溶液解脱,测试结果的重现性差。本文对此方法进行改进,采用50%王水封闭溶解试样,氯化亚锡还原,聚氨酯泡塑富集,20 g/L硫脲-20%盐酸溶液解脱,石墨炉原子吸收光谱法测定金和铂。在盐酸-氯化亚锡体系中,吸附温度为20℃,振荡时间为30 min时,金和铂的回收率均在95%以上,金和铂的检出限分别为0.23 ng/g和0.39 ng/g,精密度(RSD,n=10)分别为1.8%～10.3%和1.3%～13.3%。经国家一级标准物质验证,测定值和标准值基本相符。该方法泡塑解脱时无需高温灰化,用王水多次提取,在100℃沸水浴中即可一次完成,样品处理快捷。与高温灰化法相比,提取温度大为降低,分析流程简单,显著提高了单次测样量,且干扰小、空白值低,可以满足除王水难溶的铂矿种外大部分地质样品快速测定的需要。     

Rapid screening of Zr-containing particles from Chang’e-5 lunar soil samples for isotope geochronology: Technical roadmap for future study

New samples returned by China Chang’e-5 (CE-5) mission offer an opportunity for studying the lunar geologic longevity, space weathering, and regolith evolution. The age determination of the CE-5 samples was among the first scientific questions to be answered. However, the precious samples, most in the micrometer size range, challenge many traditional analyses on large single crystals of zircon developed for massive bulk samples. Here, we developed a non-destructive rapid screening of individual zirconium-containing particle for isotope geochronology based on a Micro X-ray fluorescence analysis (µXRF). The selected particles were verified via scanning electron microscopy (SEM), 3D X-ray microscopy (XRM), and focused ion beam scanning electron microscopy (FIB-SEM) techniques, which showed that zirconium-bearing minerals with several microns were precisely positioned and readily suitable for site-specific isotopic dating by second ion mass spectrometry (SIMS). Such protocol could be also applicable in non-destructively screening other types of particles for different scientific purposes. We therefore proposed a correlative workflow for comprehensively studying the CE-5 lunar samples from single particles on nanometer to atomic scales. Linking various microscopic and spectromicroscopic instruments together, this workflow consists of six steps: (1) single-particle selection with non-destructive µXRF technique, (2) 2D/3D morphological and structural characterization with a correlative submicron 3D XRM and nanoscale resolution FIB-SEM imaging methods, (3) SEM analysis of the surface morphology and chemistry of the selected particle, (4) a series of microscopic and microbeam analyses (e.g., SEM, electron probe microanalysis, and SIMS) on the cross-section of the selected particle to obtain structural, mineralogical, chemical, and isotopic features from the micron to nanometer scale, (5) advanced 2D/3D characterization and site-specific sample preparation of thin foil/tip specimens on a microregion of interest in the selected particle with FIB-SEM technique, and (6) comprehensive analyses on the FIB-milled specimens at nanometer to atomic scale with synchrotron-based scanning transmission X-ray microscopy, analytic transmission electron microscopy, and atom probe tomography. Following this technical roadmap, one can integrate multiple modalities into a uniform frame of multimodal and multiscale correlated datasets to acquire high-throughput information on the limited or precious terrestrial and extraterrestrial samples.     

中国南方下寒武统黑色岩系及其地质研究意义

黑色岩系是C、N、P、S、O和一些重金属的循环链,既是一种矿产资源,又是环境因素的良好载体.以我国南方下寒武统为例,讨论黑色岩系的地质研究意义,提出黑色岩系的重点研究方向.     

基于风化剥落深度的衢州古城墙小西门岩石砌块和蛎灰勾缝条长期抗风化能力研究

不同岩石在相同风化环境条件下的抗风化能力不同。如何评定岩石的抗风化能力是近年来人们十分关注的研究课题之一,因为它对岩石风化机理分析和石质文物长期保护研究有着重要的科学价值。位于浙江省衢州市的古城墙小西门建于明代晚期。小西门城墙的岩石砌块有多种岩性,它们之间的风化剥落深度相差较大。利用三维激光扫描仪测量了小西门某特定研究区中包含多种岩性的岩石砌块的风化剥落深度,并以此来评定不同岩性岩石的长期抗风化能力,以给出相应的排序。在现场还发现,与所研究的多数岩石砌块相比,被古人用作为古城墙各砌块之间勾缝的黏合材料蛎灰的抗风化能力更强。     

巴东组紫红色泥岩三轴压缩试验及本构模型研究

采用MTS压力试验系统对巴东组紫红色泥岩进行了4个不同级别围压的三轴压缩试验和单轴试验。得到了巴东组紫红色泥岩在这5个围压下的全应力-应变曲线。根据试验结果,把全应力-应变曲线分为4个主要阶段,并分析了屈服强度、峰值强度、残余强度随围压的变化规律,结果表明,它们与围压成线性增大关系,满足库伦-莫尔强度准则。同时,根据试验曲线,利用双线性-线性软化-残余理想塑性模型来模拟巴东组紫红色泥岩,并给出了每一段的本构方程,确定了相关参数,可供类似的工程参考。     

老挝岩浆岩成因

老挝的岩浆活动分为三个阶段:早期古元古代—早石炭世,中期晚石炭世—中三叠世,晚期晚三叠世—第四纪。早期以中酸性及中基性侵入岩、火山岩为主,中期从超基性—酸性均有出露,晚期则为中酸性侵入岩,火山岩及玄武岩。反映不同构造位置及成因。     

基于虚功原理的悬索桥隧道式锚碇边坡稳定性分析

本文基于虚功原理,结合工程地质勘察资料,在岩层层面和不利结构面组合切割下,由于锚碇工程荷载作用,研究坝陵河大桥西岸隧道式锚碇边坡的整体稳定性。本文的力学分析模型采用多个块体破坏机构的分析方法,假定块体的底面和侧面均达到了极限平衡状态,安全系数可通过功能平衡的虚功原理表达式来求解。功能平衡方程中仅有安全系数一个未知数,条块底部和界面上的法向压力和切向摩擦力并不出现,求解大为简化。     

金沙江下虎跳滑石板滑坡破坏机理及稳定性分析

1996年10月28日发生在金沙江下虎跳峡口的滑石板滑坡,因堵塞金沙江、摧毁公路而引起高度重视。野外调查发现,滑石板滑坡是典型结构面控制的顺层基岩滑坡,层面和两组近于垂直层面的节理将边坡厚层灰岩切割成不同规模的菱形块体,长期的风化作用、重力、降雨、人工开挖公路等因素作用下,这些菱形块体从顺层稳定状态演化为稳定性较差的悬挂体,受河谷边坡斜向割切影响,表现为梯级叠次悬挂,最外边的悬挂体稳定性最差,最容易发生快速滑动。因此,该滑坡每次发生破坏滑动的体积不会很大,但是具有多次重复发生的特点,值得高度注意。     

Sensitivity of the elastic anisotropy and seismic reflection amplitude of the Eagle Ford Shale to the presence of kerogen

The Eagle Ford Shale of Central and South Texas is currently of great interest for oil and gas exploration and production. Laboratory studies show that the Eagle Ford Shale is anisotropic, with a correlation between anisotropy and total organic carbon. Organic materials are usually more compliant than other minerals present in organic‐rich shales, and their shapes and distribution are usually anisotropic. This makes organic materials an important source of anisotropy in organic‐rich shales. Neglecting shale anisotropy may lead to incorrect estimates of rock and fluid properties derived from inversion of amplitude versus offset seismic data. Organic materials have a significant effect on the PP and PS reflection amplitudes from the Austin Chalk/Upper Eagle Ford interface, the Upper Eagle Ford/Lower Eagle Ford interface, and the Lower Eagle Ford/Buda Limestone interface. The higher kerogen content of the Lower Eagle Ford compared with that of the Upper Eagle Ford leads to a negative PP reflection amplitude that dims with offset, whereas the PS reflection coefficient increases in magnitude with increasing offset. The PP and PS reflection coefficients at the Austin Chalk/Upper Eagle Ford interface, the Upper Eagle Ford/Lower Eagle Ford interface, and the Lower Eagle Ford/Buda Limestone interface all increase in magnitude with increasing volume fraction of kerogen.     

楚雄盆地烃源岩有机地化特征及综合评价

对楚雄盆地各组段烃源岩的厚度分布特征、地化特征及成熟度特征分别进行静态研究，对各组段烃源岩的优劣及生烃潜力作出了综合评价，并预测了各区块的油气勘探前景。