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51.
野外地质调查结果显示,断层带常富集碳质.断层带中碳的分布结构是影响断层带电导率特征的一种重要参数.本文在室温、室内湿度和2MPa正应力条件下,对不同石墨含量(3,5,6和7wt%)的石英-石墨混合断层泥模拟样品开展了滑动速率介于500μm·s-1~1m·s-1的摩擦实验及相应的电导率测量,以期研究断层运动对碳分布结构的影响以及断层带电性特征对碳含量及分布的响应情况.结果显示,摩擦滑动能够显著地改变样品的电性特征(电导率大小及其各向异性).在平行滑动面方向(径向),样品电导率随着滑动位移的增加快速增加,在滑动约数十厘米之后,其电导率基本达到稳定状态;在垂直滑动面方向(轴向),样品电导率基本不随摩擦滑动速率和滑动距离而变化.SEM显微结构观测显示,摩擦滑动所引起的电导率各向异性直接反映了石墨分布结构的变化.该研究结果深化了对地震断裂带浅部电性特征的认识,为野外断层带大地电磁测深资料的解释提供了约束,同时对于了解含碳断层的力学性质和弱矿物相在剪切变形中的分布特征及其演化过程等方面也具有重要意义. 相似文献
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This paper describes unusual graphite–sulfide deposits in ultramafic rocks from the Serranía de Ronda (Spain) and Beni Bousera (Morocco). These deposits occur as veins, stockworks and irregular masses, ranging in size from some centimeters to a few meters in thickness. The primary mineral assemblage mainly consists of Fe–Ni–Cu sulfides (pyrrhotite, pentlandite, chalcopyrite and cubanite), graphite and chromite. Weathering occurs in some sulfide-poor deposits that consist of graphite (up to 90%), chromite and goethite. Texturally, graphite may occur as flakes or clusters of flakes and as rounded, nodule-like aggregates. Graphite is highly crystalline and shows light carbon isotopic signatures (δ13C≈− 15‰ to − 21‰). Occasionally, some nodule-like graphite aggregates display large isotopic zoning with heavier cubic forms (probably graphite pseudomorphs after diamond with δ13C up to − 3.3‰) coated by progressively lighter flakes outwards (δ13C up to − 15.2‰).Asthenospheric-derived melts originated the partial melting (and melt–rock reactions) of peridotites and pyroxenites generating residual melts from which the graphite–sulfide deposits were formed. These residual melts concentrated volatile components (mainly CO2 and H2O), as well as S, As, and chalcophile elements. Carbon was incorporated into the melts from the melt–rock reactions of graphite-bearing (formerly diamonds) garnet pyroxenites with infiltrated asthenospheric melts. Graphite-rich garnet pyroxenites formed through the UHP transformation of subducted kerogen-rich crustal material into the mantle. Thus, graphite in most of the studied occurrences has light (biogenic) carbon signatures. Locally, reaction of the light carbon in the melts with relicts of 13C-enriched graphitized diamonds (probably generated from hydrothermal calcite veins in the subducting oceanic crust) reacted with the partial melts to form isotopically zoned nodule-like graphite aggregates. 相似文献
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原子吸收法测定矿泉水中的镉元素 总被引:2,自引:0,他引:2
提出用石墨炉原子吸收法直接测定饮用天然矿泉水中痕量镉元素方法。以磷酸氢二钾作基本体改进剂,可提高灰化温度和灵敏度,消除共存元素的干扰,方法的检出限为0.004ug/L,相对标准偏差(RSD,n=10)为3.7% 相似文献
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新疆苏吉泉球状石墨矿床成矿模式 总被引:3,自引:0,他引:3
东准噶尔苏吉泉石墨矿赋存于黄羊山复式花岗岩体的黑云母碱长花岗岩和角闪碱长花岗岩接触带,构成NW向延伸的长英质石墨混染带.矿体多呈不规则透镜状,平面上为短轴或近似等轴状,主矿体附近发育有巢状或小透镜状矿体.矿石多具球状构造,石墨球体间为石英和长石组成的致密长英质胶结物,球体除石墨外还有含量不等的粗粒自形长石、石英和云母等.利用X射线粉晶衍射技术、DTA分析及显微镜下观察,对该矿床特征进行研究并与国内其他石墨矿床进行地质学、矿物学研究对比,发现其晶胞参数和晶胞体积最小,放热峰起始温度最高及有序度最好.结合前人δ13C同位素分析结果,认为成矿物质为有机碳,矿床属岩浆成因. 相似文献
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阳极焙烧炉的燃烧计算与分析 总被引:1,自引:1,他引:0
采用计算燃烧学的原理和模型以及CFD软件对以重油作为燃料的阳极焙烧炉炉内的流动、燃烧过程进行了模拟计算,讨论了炉内温度场、流场和各组分浓度场的分布规律,分析了这些因素对碳阳极焙烧质量的影响.研究表明,在设计阳极焙烧炉结构时应考虑火道中挡板对气流分布的影响. 相似文献
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We report here on two distinct processes of deformation affecting graphite in fault zones of the Hidaka metamorphic belt, Hokkaido, Japan. One process involves the micrometer-scale delamination (MMD) in the stacking of graphite, and the other is the nanometer-scale delamination (NMD) in the stacking plus pulverization (P) of carbon sheets to less than 10 nm. Graphite in mylonites mainly glide along the (002) planes, and they exhibit layer separation, kink banding, and bending structures produced by MMD processes, whereas NMD + P processes induce a significant size reduction and amorphization of the graphitic structures in cataclasites, ultracataclasites, and pseudotachylytes. The strain-induced amorphization of graphite, as inferred from XRD and micro-Raman spectroscopy, corresponds well with nano-to micro-scale deformation structures observed under the HRTEM, suggesting a systematic increase of edge planes by interlayer delamination and pulverization of carbon sheets. In addition, the carbon isotopic compositions of the graphite in fault rocks have negative δ13C signatures, indicating a sedimentary organic origin; such graphite has a tendency to accumulate within the shear bands. Our data suggest that the graphitic structures record information on both the peak metamorphic temperatures and the deformation processes, and they show the progressive amorphization with increasing brittle deformation. 相似文献