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X射线荧光光谱-电子探针在中酸性火山岩鉴定中的应用 总被引：2，自引：1，他引：1
中酸性火山岩多具斑状结构,基质可见微晶状结构、隐晶状结构、玻璃质结构等,由于基质矿物颗粒多细小,常用的偏光显微镜受放大倍数的限制,很难准确鉴定矿物种属及含量,这类岩石仅依靠偏光显微镜分类命名会存在误差。本文采用X射线荧光光谱(XRF)、电子探针(EMPA)和偏光显微镜下观察相结合的方法,对中酸性火山岩进行鉴定。结果表明:对于基质呈隐晶质、显微晶质的中酸性火山岩,基质特征相似,偏光显微镜下无法确定长石、石英的含量,因此无法对岩石准确命名;再通过XRF进行主量元素分析,并对分析结果进行标准矿物QAPF双三角图解分类、TAS图解分类及李氏火山岩定量分类,对比结果显示三种分类命名方法存在差异;通过电子探针对矿物进行校验显示,QAPF及李氏火山岩定量分类图解与显微镜下鉴定相符,TAS图解与其他分析结果存在一定偏差。因此,对于中酸性火山岩准确命名,应采用多种分析方法相结合的方式,避免测试单一引起的误差。 相似文献
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We have studied the evolution of the texture in two granites and two limestones subjected to slow and uniform temperature change. Each granite has a different grain size and each limestone a different texture: Carrare crystalline limestone and Crepey oolitic limestone. Temperature was varied from 200°C to 700°C. Scanning Electron Microscope observations of different rock samples show that during thermal cycling intercrystalline boundaries in granites widen out progressively and porosity increases. New microcracks appear in crystals between 500°C and 600°C. In Carrare crystalline limestone, intercrystalline cracks appear at temperatures as low as 200°C. Due to its heterogeneous cracks appear at temperatures as low as 200°C. Due to its heterogeneous increasing temperature. Longitudinal wave velocity and intrinsic permeability show good correlation with the Scanning Electron Microscope observations. 相似文献
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Germana Barone Mauro Francesco La Russa Antonino Lo Giudice Paolo Mazzoleni Antonino Pezzino 《Environmental Geology》2008,55(3):499-504
The Cathedral of St. Giorgio in Ragusa Ibla (Sicily) is one of the most important Baroque monuments of eastern Sicily. The restoration of the monument underway has put forward notable questions regarding the stone materials used and their state of degradation. The façade appears to be made mainly of a creamy white calcarenite, and of mortars and plasters. However, detailed analysis has highlighted a more complex use of the raw material. The mortar and plaster have a different composition in regards to their architectural use while the natural stone material is distinguished not only by a creamy-white calcarenite but also by a dark coloured bituminous calcarenite (pitch rock), which now appears whiter because of superficial chromatic alterations. This process was reproduced in the laboratory using an accelerated aging technique on samples of bituminous calcarenite, which allowed the cause of the alternation to be identified as photo-oxidation of the asphaltenes. Following this process of photo-oxidation, other forms of chromatic alterations affected the façade (brown–orange-coloured patinas). FTIR, Scanning Electron Microscope and thin section microscopic observation allowed the characterization of also the products of this process to be carried out, highlighting the complex mechanism which the processes underwent. 相似文献
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文章对石膏原岩在静水溶蚀条件下的时间-温度效应进行了初步研究,并从微观角度对石膏岩溶蚀破坏机理进行分析。试验发现随着溶液温度的升高、溶蚀时间的延长,石膏岩溶蚀破坏加剧。具体表现为:石膏岩失重率随温度升高、时间延长而增大,溶蚀速率均值随温度升高而增大;溶液中Ca^2+浓度随温度升高、时间延长而增大,Ca^2+浓度增长速率均值随温度升高而增大。Fick扩散及溶胀应力是石膏岩溶蚀破坏的主要原因。静水溶蚀条件下,石膏原岩主要溶蚀破坏形式为:溶胀裂缝、柱状劈裂及片状剥离。 相似文献
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Summary
By means of spectral analysis, the measured normal forces, tangential forces, and side forces acting on two button cutters
on the boring machine in ?sp? Hard Rock Laboratory were analysed and the basic characteristics of the cutter forces were determined.
After the measurements of the cutter forces, some rock core samples were taken from the bottom and the wall of the test borehole.
These samples were cut, polished, and examined by means of a Scanning Electron Microscope (SEM). The lengths of the major
cracks in the rock samples were measured, and a relation between the length of the median cracks and the relevant cutter forces
was investigated.
Received October 5, 2001; accepted June 25, 2002; Published online November 19, 2002 相似文献
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The existence of a small population of ‘relict rock glaciers’ scattered across the main British mountain areas has previously been inferred from published cases of individual sites or local clusters. Discrete debris accumulations (DDAs) of widely differing character have been identified as ice‐debris landforms (whether ‘rock glaciers’ or ‘protalus lobes’) partly from morphological, sedimentological and topo‐locational evidence, but principally by analogy with both active and relict examples in present‐day arctic/alpine environments, with consequent palaeoclimate inferences. However, re‐interpretation of several supposed rock glaciers as rock slope failures has cast doubt on both the palaeoclimatic reconstructions and the origin of the remaining features. Issues of polygenesis and mimicry/equifinality have contributed to some previous misidentifications. We re‐evaluate the 28 candidate cases based on new field and image‐analysis evidence and place them on a continuum from no ice presence through passive ice presence and glacial shaping to emplacement onto glacier ice with consequent melt‐out topography. A null hypothesis approach (that there are no relict rock glaciers in the British mountains) is pursued, and the evidence indicates that none of the 28 cases clearly warrants classification as a relict rock glacier; their characteristics can be explained without recourse to any significant forward debris movement controlled or facilitated by incorporated or underlying ice as it deforms and melts out. However, only one‐third of the candidate DDAs are attributed in whole or part to rock slope failure (sensu stricto), with other debris sources including incremental rockfall, bedrock knolls with coarse debris veneer, protalus rampart and moraine. A few cases deserve more detailed investigation of their structure, morphology and sediments within a broader local glaciological/topographical context, with multitemporal/polygenetic evolution in mind. But it is for future researchers to demonstrate that deforming ice played an incontestable part in shaping these often enigmatic DDAs, given that other causes are simpler and commoner. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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以海拉尔盆地贝尔凹陷大磨拐河组-伊敏组的含片钠铝石火山碎屑岩为研究对象,采用偏光显微镜、扫描电镜及配套能谱、茜素红 S染色、阴极发光和X 射线衍射分析等技术手段,对研究样品的岩石类型、自生矿物种类及共生序列进行了详细研究。贝尔凹陷发育片钠铝石的宿主岩石类型为沉凝灰岩,自生矿物以发育片钠铝石、铁白云石和菱铁矿三种碳酸盐矿物为主,片钠铝石含量高达25%。成岩共生序列为菱铁矿Ⅰ→高岭石、石英次生加大→片钠铝石→微晶石英→方解石→铁白云石→菱铁矿Ⅱ→沥青。不同于国内外其它地区发现片钠铝石的主要产状为充填孔隙,本区内发育的片钠铝石以交代长石、石英、岩屑颗粒和高岭石基质为赋存特征,表明沉凝灰岩中的长石、岩屑、高岭石基质可以为其提供金属离子物质来源,并在CO2参与下,与成岩流体反应生成片钠铝石。大量碳酸盐矿物（15-44%）的发育证明了火山碎屑岩具有较高的CO2矿物捕获能力。 相似文献
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海绿石是海相沉积的指相矿物,通常形成于海进系列,与低的沉积物供应速率有关。本文利用岩相和扫描电子显微镜(SEM)对样品进行了详细的观察,并运用X射线粉晶衍射(XRD)、傅立叶变换红外吸收光谱(FTIR)、电子探针微分析(EPMA)等技术,对藏西南札达县波林地区夏拉剖面中的海绿石砂岩和含海绿石灰岩样品进行了系统的分析与研究。上述分析表明砂岩和灰岩中的海绿石均为高演化的海绿石,砂岩中的海绿石为原地海绿石,而灰岩中的海绿石则源于下伏砂岩。通过沉积环境分析和区域地层对比,笔者等认为札达地区砂岩中海绿石的出现可能与Albian晚期印度大陆从澳大利亚—南极大陆的彻底裂解而造成的该地区的海进有关。持续的海进过程导致了该地区高演化的海绿石的形成。 相似文献
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Amar Deep Regmi Kohki Yoshida Megh Raj Dhital Biswajeet Pradhan 《Environmental Earth Sciences》2014,71(6):2711-2727
Sangrumba landslide is one of the largest and the most active landslides in Nepal Himalaya. Geologically the landslide belongs to the Higher Himalaya and consists of Pre-Cambrian biotite–garnet and sillimanite gneiss with some quartzite. The present paper aims at describing various degrees of rock weathering and their effect in Sangrumba landslide. Field study followed by mineralogical, geochemical and geotechnical analyses of the collected rock and soil samples from the landslide zone were used in characterizing weathering degree. The gneisses are intensely weathered while quartzite is unweathered. Petrographical and X-ray diffraction analyses showed that the rocks in the landslide zone had undergone weathering process with the formation of different types of clay minerals as kaolinite, vermiculite, smectite and chlorite. This was further confirmed by the Scan Electron Microscope and Energy Dispersive X-ray analyses. These clay minerals drastically reduced the rock strength facilitating the extensive failure of the Sangrumba landslide. The major and trace element composition of the rock and soil samples was calculated from the XRF analyses. The geochemical analyses and weathering indexes of rocks showed that they are significantly weathered and had a major influence in the formation of the Sangrumba landslide. In addition, mechanical strength measurement of rock/soil showed that the strength drastically decreases as the weathering intensity increases. Rainfall followed by the rock type are the most dominant parameters influencing the weathering process which leads to the formation of large landslide as the present one. These findings can be used in other areas with similar geological and topographical conditions. 相似文献
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酸雨作为一种常见自然灾害,不但会对环境产生污染和破坏,也会引起岩土体的失稳破坏如边坡垮塌等,学者们对后者的研究较少。酸雨区基性/超基性岩质边坡失稳现象常见,但结合酸雨影响的失稳机理尚有待研究。本文以典型酸雨区雅安境内一辉长岩边坡为例,首先设计了岩石酸雨化学风化模拟实验,开展了不同贯通度和酸雨作用历时的辉长岩结构面酸蚀作用研究;通过岩体结构面直接剪切试验及边坡稳定性计算对比分析了不同酸雨作用历时条件下的边坡滑动稳定性,论证了酸雨作用对边坡稳定性的显著弱化作用。通过对酸雨作用前后试样的X衍射测试（XRD）、偏光显微镜薄片观察、扫描电子显微镜测试（SEM）提出了酸雨显著弱化边坡稳定性的内在原因,认为辉长岩边坡酸雨弱化机理主要体现在两个方面:岩石中的链状硅酸盐矿物（辉石）和架状硅酸盐矿物（基性斜长石）酸蚀为层状硅酸盐矿物（绿泥石、伊利石及高岭石）,显著降低结构面抗剪强度;可溶盐及部分黏土矿物逐渐被酸雨溶解携运流失,结构面上逐渐发育裂隙,使潜在滑面有效抗剪面积减小。研究成果可为酸雨地区的岩土体稳定性分析评价及加固工程设计提供参考 相似文献
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A. F. Trendall 《Australian Journal of Earth Sciences》2013,60(2):517-526
There is no generally accepted time or time‐rock Precambrian stratigraphy, as there is for the Phanerozoic. Many authors suggest that a time‐rock nomenclature based on similar principles should be used. But no explicit general principles for the erection of major time or time‐rock stratigraphic divisions exist, or have even been used, while the confusion caused by the evolutionary and unsystematic growth of the Phanerozoic systems is admitted. Consequently, geologists dealing with the Precambrian may feel free to choose whatever methods of time subdivision and nomenclature seem most effective, unprejudiced by Phanerozoic precedent. The familiar ones used by historians seem to be more useful for Precambrian rocks and time, if megacenturies (of 108 years, or 106 centuries) are used instead of centuries, than those used in Phanerozoic stratigraphy. The conclusions that: (1) stratigraphic rock units, plus isotopic age determinations to inter‐relate major sequences and events within a numerical time‐scale of years, are together adequate for handling Precambrian stratigraphic problems, and conversely (2) traditional time and time‐rock stratigraphy is superfluous, represent the main thesis of this paper. Although there is no rock unit of system rank the local restriction of systems would overcome this deficiency; the Adelaide System is an example. Three common fallacies are: (1) rocks are the primary standard of reference for time, (2) geological maps cannot be published without time‐rock stratigraphy, and (3) the same type of nomenclature must be used for both Phanerozoic and Precambrian. International cooperation in the adoption of standard rocks for isotopic dating is advisable to promote accurate correlations in the Precambrian. 相似文献
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SONG Eping ZHANG Kexin CHEN Jiangjun WANG Chaowen JIANG Gaolei YIN Ke HONG Hanlie CHURCHMAN Jock Gordon 《《地质学报》英文版》2014,88(5):1579-1591
This study collected the early Oligocene to middle Miocene sediments from the Gerze Basin of Tibet, and used X-Ray diffraction （XRD） and Scanning Electron Microscope （SEM） to discuss their clay mineralolgy, clay indices, better understand the clay mineralogy and its paleoclimatic significance. The results show that clay minerals of the Gerze Basin sediments are mainly composed of iilite and chlorite, with minor amounts of smectite and kaolinite, and their relative content varies along the section. Variations of relative contents and clay indices suggest that the Gerze Basin has experienced three-stage evolution of paleoclimate： I ） high ilUte and chlorite contents, with fluctuant smectite and low （I＋Ch）/（K＋S） ratio, indicative of a dominant seasonal arid climate from the early Oligoeene to late Oligocene; Ⅱ） higher illite and chlorite contents and larger （I＋Ch）/（K＋S） ratio but absence of kaolinite, indicating a colder and drier climate from the late Oligocene to early Miocene; Ⅲ） high iilite and chlorite contents with fluctuant （I＋Ch）/（K＋S） ratios and occasional occurrence of kaolinite, suggesting that the climate became warmer and more humid compared with that of stage Ⅱ in the mid-Miocene. These conclusions were also reinforced by the clay morphology, which suggests that physical weathering dominated in stage Ⅱ, while relatively strong chemical weathering was dominant in stages Ⅰ and Ⅲ Clay minerals of the sediments mainly consist of illite and chlorite, indicating that the source rock played a significant role in clay origin. It is inferred that global cooling and the enhancement of denudation and obstruction of northward moisture due to the uplift of the Qinghai-Tibet Plateau were responsible for the provenance of iUite and chlorite under weak chemical weathering. Though the Qinghai-Tibet Plateau reached a certain elevation by the mid-Miocene, yet the mid-Miocene widespread warming might have largely impacted the Gerze climate. 相似文献
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B. J. J. Embleton 《Australian Journal of Earth Sciences》2013,60(1-2):121-122
Volcanic rocks, mainly of intermediate composition, occupy several basins within the rift zone along which the Yangtze River flows in its lower reaches. Potassium‐argon (K‐Ar) age measurements on minerals and whole rock samples from lavas and syenitic intrusives in the Lujiang‐Tzungyang volcanic basin range from 131 to 123 m.y., and biotites from two lavas in the Nanjing‐Wuhu basin have measured ages of 127 and 130 m.y. Incremental heating experiments by the 40Ar/39Ar method on biotite from two volcanic rocks, one from each basin, yield simple age spectra with plateau ages of 129 to 130 m.y. These data provide evidence that the two biotites have remained undisturbed since crystallisation. The combined results show that volcanism was contemporaneous within the two basins in the Early Cretaceous. Vol‐canism in the Yangtze Volcanic Zone is thought to be related to adjustments within the Eurasian plate as a consequence of collision between the earlier Pacific (Kula) plate and the Eurasian plate. 相似文献
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应用电子微探针-扫描电镜-拉曼光谱-电子背散射衍射研究一种未知Ti-Zr-U氧化物的矿物学特征 总被引：3，自引：2，他引：1
本文应用电子微探针(EPMA)、扫描电镜(SEM)在阿尔金地区的榴闪岩中发现了一种微米级含铀氧化物矿物,结合光学显微镜、拉曼光谱和电子背散射衍射(EBSD)技术对该矿物的化学成分、赋存状态、物理及光学性质、晶体结构等矿物学特征进行了研究。结果表明,该矿物在空间上与钛铁矿关系密切且主要产于其边部,为一种不透明矿物;主要化学组成为TiO2、ZrO2和UO2,实验化学式为(Zr,U)Ti2O6,其中U与Zr互为类质同象替代;具独特的拉曼光谱特征,初步确定为斜方晶系且具有序的铌钙矿结构。通过电子微探针U-Th-Pb定年获得等时线年龄为451±49Ma,可能代表了寄主岩石的退变质年龄。将该矿物与化学成分类似的晶体进行对比,发现与斯里兰卡石等已知天然矿物存在差异,而与一种人工合成晶体Zr5Ti7O24在化学成分和晶体结构上较为相似,可以初步推断Ti-Zr-U氧化物为一种未被人们发现的新矿物。 相似文献
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Integrated geophysical and geological studies for mineral prospecting in Betul-Chhindwara belt (BCB), Central India 总被引：1，自引：0，他引：1
Dewashish Kumar D. V. Subba Rao K. Sridhar M. Satyanarayanan Prasanta K. Patro 《Journal of the Geological Society of India》2016,87(4):383-396
Integrated study combining high resolution electrical resistivity tomography and time domain induced polarization was carried out in Betul-Chhindwara belt Madhya Pradesh, Central India in order to evaluate and delineate the polymetallic sulphide mineralization, its nature, type of deposit and depth. On interpretation of the models results clear cut anomalies revealed showing chargeability ～2 to 54 mV/V up to a maximum depth of 131m. This range of chargeability signify signature of metallic conductor. Nevertheless the basement rock is clearly mapped, showing substantial resistivity contrast. In addition detailed analysis of the integrated results from geology, geochemistry and Scanning Electron Microscope–Energy Dispersive X-ray Spectroscopy resulted from in situ rock samples shows good correlation with resistivity and IP results. This integrated study confirms the presence of conducting sulphide mineral ore body and the results and findings need test drilling at the geophysical anomalous site(s) to confirm the depth persistence and evaluate the metallic conductor. 相似文献
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KERSTIN KOLDITZ OLAF DELLWIG JAN BARKOWSKI RAINER BAHLO THOMAS LEIPE HOLGER FREUND HANS‐JÜRGEN BRUMSACK 《Sedimentology》2012,59(2):337-355
The barrier islands of the southern North Sea were formed during the Holocene sea‐level rise. These islands form part of a highly dynamic environment whose evolution continues today. Subjected to sea‐level changes, tides and storm events, the sedimentary record reflects processes occurring under varying energy conditions. This article presents geochemical, mineralogical and diatom investigations carried out in the salt marsh of the East Frisian barrier island of Langeoog, which is re‐exposed to a rising sea‐level due to de‐embankment. The major aim of this study is to improve the knowledge of the sedimentological and geochemical development of these deposits under the influence of sea‐level rise, with a special focus on the geochemistry and distribution of heavy mineral‐associated elements. Correlation diagrams between FeO, TiO2 and MnO, as well as ternary plots (Al2O3–SiO2–Zr or TiO2), clearly indicate the variable appearance of heavy minerals in different lithological facies, comprising marsh soil, mixed and sand flat, and relocated beach sands. A dominating abundance of ilmenite followed by zircon, garnets and some other heavy minerals is evidenced by Scanning Electron Microscope‐Energy Dispersive X‐ray measurements. The data presented here suggests that these geochemical proxies are useful tools for characterizing depositional energy conditions. Increasing depositional energy is evident for the lithological units in the following order: marsh soil, mixed flat, sand flat and relocated beach sand. The energetic conditions during sediment deposition, as well as the sedimentary history, are confirmed by diatom analyses as an additional independent indicator. Depending on source rock composition, the geochemical parameters used in this study may also help to investigate depositional energy regimes of other siliciclastic sedimentary systems. 相似文献
19.
Textural, electron microprobe and whole rock geochemical evidence from carbonatites and associated silicate rocks on Alnö Island, Sweden, suggest that the carbonatite, at the time of emplacement, could have been an (almost) pure CaCO3 liquid with a high volatile (H2O–CO2) content and that most silicate minerals, which are ubiquitously present, are either (1) assimilated from the surrounding wall rock, by progressive and coupled fragmentation and corrosion; or (2) by‐products of corrosive interaction between the carbonatite liquid and the wall rock. This interpretation is supported by balancing a reaction to describe interaction between carbonatite and a cpx + ne‐bearing (ijolite) wall rock. Although our analysis does not preclude the possibility that fenitizing agents (e.g. Na, Fe) were transported by the carbonatite liquid, these components are not required to drive the observed mineralogical changes in the carbonatite. 相似文献
20.
合徐高速公路南段膨胀土矿物成分及微结构 总被引：2，自引：1，他引：2
运用X—射线衍射、偏光显微镜、扫描电镜以及化学全量分析等方法,对合徐高速公路南段膨胀土的矿物组分及微结构等方面进行较为深入的研究,探明其特殊的工程性质不仅与膨胀土的矿物组分、阳离子交换量有关,更与其微结构密切相关,特别是其结构联结特征;膨胀土的胀缩特性随着粘土矿物含量的增大,特别是蒙脱石、阳离子交换量能力的增强而增强;土的微结构是控制膨胀土胀缩性的另一个重要因素,随着粘土基质中的卷曲片状物质的增多而增强,而膨胀土的物理力学性质很大程度上取决于膨胀土粘土颗粒之间的结合连接程度。 相似文献