岩爆形成机制与判据研究   总被引：25，自引：5，他引：25  

徐林生  王兰生  李永林 《岩土力学》2002,23(3):300-303

根据岩爆实例调研，详细地描述了岩爆破坏的几何形态特征，并通过岩爆岩石断口扫描电镜分析和岩爆岩石力学测试等研究，总结出岩爆形成的力学机制主要有压致拉裂，压致剪切拉裂，弯曲鼓折（溃屈）等3种基本类型。现场测试结果则表明，岩爆发生时，其判据σθ／Rb至少应大于0．3。  相似文献   

扫描电子显微镜对花岗岩中主要矿物裂隙作用的研究(英文)     

唐春安  张哲 《地质与资源》2004,13(3)

微裂隙对于岩石的物理性质有重要影响.通过光学显微镜对显微裂隙进行的观察,难以将薄片的制作过程中产生的裂隙同自然裂隙区分;其次,观测的裂隙大小限制在0.1mm或以上数量级,一些重要细节观察不到.扫描电镜的高放大倍数和三维分辨率使其成为适合于裂隙研究的理想工具.利用扫描电镜观测了浙江花岗岩在室温下由51.6MPa压力产生的裂隙的发育过程.观察花岗岩的表面以研究其微裂隙和矿物的解理、晶形及破裂作用.微裂隙分为3种类型:晶体内裂隙(完全发育在颗粒内部),晶体间裂隙(穿过颗粒边界进入其他颗粒中),颗粒边界裂隙(沿颗粒边界发育或与边界重合).本研究中的花岗岩为中—粗粒(1～6mm),经过蚀变,约含40%斜长石,25%钾长石,25%石英,10%镁铁矿物(主要为黑云母和白云母).(1)石英裂隙表面的石英颗粒具有边界破裂和贯穿颗粒破裂.贯穿石英颗粒的破裂常呈贝壳状断口.变形集中带与滑动面相伴,其上发育有擦痕和沟槽,这是石英典型的脆性破裂类型.石英矿物的贝壳状破裂产状指示其变形作用早期的碎裂作用,在变形作用中发生交代作用.一些平滑的破裂面上没有石英颗粒的微裂隙构造,但在石英表面却有明显的擦痕面,可指示应力的方向.由于石英的各向异性,这些面也是由贯穿颗粒破裂所形成.一些开放的裂隙集中于石英晶体之中或沿  相似文献   

Direct analysis of microaggregates shrinkage for drying: Application to microaggregates from a Brasilian clayey Ferralsol     

Nathalie Volland-Tuduri  Michel Brossard  Ary Bruand  Henri Garreau 《Comptes Rendus Geoscience》2004,336(11):1017-1024

Subrounded microaggregates 100 to 500 μm in diameter were collected in a Ferralsol located in the state of Goiàs. Observation of these microaggregates in dry conditions in scanning electron microscopy showed morphological characteristics that are representative of microaggregates described earlier in many Ferralsols. The shrinkage for drying of initially water saturated microaggregates was studied using an environmental scanning electron microscope. Results showed very small shrinkage for the microaggregates usually studied. However, the shrinkage varies since the volume of dried microaggregates was found to be 93 to 99% of their volume when they are saturated. To cite this article: N. Volland-Tuduri et al., C. R. Geoscience 336 (2004).  相似文献   

我国岩土钻掘技术回顾与发展对策研究     

张辉旭  殷琨 《探矿工程》2004,31(3):1-6,9

以国土资源部探矿工程类研究所岩土钻掘技术创新、发展应用及存在问题为切入点，通过简要回顾我国岩土钻掘技术的发展，对我国岩土钻掘技术发展对策进行了研究，提出了我国岩土钻掘技术的发展对策与建议，主要提出了国土资源部探矿工程类研究所岩土钻掘技术既要为国家地质工作提供钻掘技术支撑，更要积极为国家经济建设服务，以及在此基础上建设国家钻掘技术支撑体系、适时进行专业学科结构调整等多条对策和建议。  相似文献   

Evaluation of Lidar and Medium Scale Photogrammetry for Detecting Soft-Cliff Coastal Change   总被引：3，自引：0，他引：3  

James Adams  & Jim Chandler 《The Photogrammetric Record》2002,17(99):405-418

Lidar and photogrammetry have both been evaluated for detecting shortterm coastal change using the Black Ven mudslide, Dorset as a case study. A lidar-generated digital elevation model (DEM) was obtained and initially compared with a DEM generated using available 1:7500 scale aerial photography and automated digital photogrammetry. The quality of these two data sets was assessed using a third DEM, derived using a total station and conventional ground survey methods. The vertical accuracies (rms error) of the lidar and photogrammetry were 0.26m and 0.43m respectively, although both data sets displayed a tendency to generate heights slightly lower than the elevation of the terrain surface. The quality of the two data sets was then assessed with respect to local slope angle. The accuracy of photogrammetrically derived elevations varied with slope and more so than in the case of lidar
From these basic tests, lidar has proved to be more accurate than photogrammetry for soft-cliff. monitoring. Further research is required to establish whether this trend is applicable to other data sets and specifically for photogrammetric data acquired using larger scale imagery  相似文献   

Quantification of ferrous/ferric ratios in minerals: new evaluation schemes of Fe L 23 electron energy-loss near-edge spectra   总被引：1，自引：0，他引：1  

P. A. van Aken  B. Liebscher 《Physics and Chemistry of Minerals》2002,29(3):188-200

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影响机载激光扫描测高精度的系统误差分析   总被引：20，自引：1，他引：20  

刘经南  张小红  李征航 《武汉大学学报(信息科学版)》2002,27(2):111-117

简要介绍了机载激光扫描测高技术的系统组成和发展现状，通过坐标转换技术建立起机载激光扫描对地定位的基本几何关系，并从这些几何关系出发，着重分析了动态偏心改正及动态时效误差对机载激光测高精度的影响，对不同的误差源如何影响定位结果的精度进行了讨论，最后给出模拟计算结果，得出了一些有益的结论。  相似文献   

Economical digital photomicroscopy     

Sybille Wunsam  John C. Bowman 《Journal of Paleolimnology》2001,25(3):399-403

Public domain software has been developed for remote exposure control of a consumer digital camera for use in photomicroscopy. A computer-controlled shutter release and remote control of various camera functions are essential to avoid mechanical disturbance of the microscope and slide during the imaging procedure. These features have previously been available only with expensive professional models. The digital images of diatom specimens obtained with this system captured the same detail as conventional photographs. The setup can therefore be used as a cost-effective tool for documenting taxonomic information of microscopically small organisms. In combination with the fast data transfer rates available via the Internet, microscopical studies can now be performed faster, more reliably, and more consistently.  相似文献   

Characterization of diatom-derived lipids and chlorophyll within Holocene laminites, Saanich Inlet, British Columbia, using conventional and laser scanning fluorescence microscopy     

L. D. Stasiuk  H. Sanei 《Organic Geochemistry》2001,32(12)

Conventional fluorescence microscopy and visible light region fluorescence microspectrometry have been combined with laser scanning fluorescence microscopy (LSFM) to examine and characterize soluble sedimentary organic matter (SOM) in Holocene diatomaceous laminites from ODP core 1034, Saanich Inlet, British Columbia, Canada. Microscopic SOM in the laminites is dominated by two components: red-fluorescing chlorophyllinite, and yellow-fluorescing, diatom-derived oils. Both are commonly preserved within the interior of siliceous diatom auxospores and appear as an abundant and intense stain on mineral matter throughout the laminites. The mineral stain is classified as matrix chlorophyllinite and matrix oil, respectively. Accessory insoluble SOM consists of dinoflagellate, prasinophyte and coccoidal alginites, and rare woody huminite, funginite, and sporinite. Visible light region fluorescence microspectrometry of chlorophyllinite reveals a predominance at λ max 670–675 nm, which is consistent with a chlorophyll a source based on comparison with reference samples of chlorophyll a and b. The consistency in λmax and spectral character of chlorophyllinite with increasing depth in Saanich Inlet correlates with a high degree of chlorophyll preservation. Its distribution in the laminites is readily imaged by LSFM using either UV (363 nm) or blue (488 nm) laser excitation and >665 nm emission. Yellow-fluorescing diatom oils have λmax ranging from 485 to 520 nm, suggesting that they may comprise up to 70% saturates. The distribution of entrapped yellow-fluorescing diatom oils as well as matrix oils is also readily imaged with LSFM using a combination of UV laser excitation (363 nm) and 510 ±40 nm emission. Laminae in the Saanich Inlet samples which are highly enriched in both diatom oils and ‘reproductive’ auxospore cells are interpreted as recording intense episodic spring diatom blooms. The observations reported here document microscopically, in situ, possibly pristine preservation of diatom oils (including possible fatty acids) at appreciable depths within Holocene organic-rich laminites. Their recognition in recent and older strata is important, for they serve as potential biomarkers for assessing long term geo-environmental changes such as water temperature. The periodic presence of anomalously high amounts of diatom-derived biological oils in laminae within the recent sediments may mark times of unusually high nutrient levels and paleoproductivity.  相似文献   

扫描质子探针研究磁铁矿中的元素分布   总被引：1，自引：0，他引：1  

张建军  周世俊 《岩矿测试》1993,12(1):24-27

选取有代表性的磁铁矿样品,研究了Fe、Mn、s、P等元素在500μm×500μm区域内的分布情况,初步探讨了Fe的聚集状态和S、P的均匀分布状况在地球化学、冶金学上的应用。  相似文献