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1.
在分析和总结前人对红藻石和蓝藻石研究成果基础上,结合岩石薄片显微镜下观察实例,发现在以往碳酸盐岩颗粒分类中没有红藻石和蓝藻石的合适位置。鉴于红藻石重要的成因意义和造礁作用,有必要明确红藻石的概念和归属。珊瑚藻本身极易钙化,经生物矿化作用最终保存下来的珊瑚藻屑一直放在生物碎屑中,而红藻石是由非固着的珊瑚藻构成的钙质独立结核,因此也可以被划分到生物碎屑中。蓝藻石作为蓝细菌钙化作用的产物,同时鉴于蓝藻石的广泛存在,把钙化蓝细菌形成的核形石命名为蓝藻石,这一重要概念从提出到现在一直被使用。然而蓝绿藻概念已变更为蓝细菌,蓝藻石的形成与藻类无关,显然将其称作蓝菌石更加确切。因此,应将红藻石和蓝藻石分别归为生物碎屑和核形石当中,并用新的术语蓝菌石替代蓝藻石。其意义在于使红藻石和蓝藻石的概念及归属更为规范,并为碳酸盐岩颗粒的深入研究提供有益线索。 相似文献
2.
研究桩与岩石的侧摩阻力组成及影响因素,有助于准确地把握桩与岩石的侧摩阻力取值原则。在对桩与岩层的摩擦黏着机制分析的基础上,指出界面力与岩层抗剪力的区别,并提出岩层的极限侧摩阻力由界面强度及岩石强度两者较弱一方决定的观点。进行了中风化岩中4组混凝土短桩的抗压及抗拔极限摩阻力对比试验,获得了相应的极限侧摩阻力值以及抗拔与抗压极限侧摩阻力值的比值。抗拔时由于上部岩层对桩侧岩层的约束作用较弱,会使侧摩阻力相对抗压时有较大降低。通过有限元计算及其与试验值的比较分析,研究短桩与岩层的界面强度条件,发现岩层和混凝土灌注桩间的侧摩阻力中界面黏着力占很大比例。 相似文献
3.
宝玉石产地来源的研究是近几年地质学、宝石学和考古学界的热门话题之一。一方面,不同产地来源的宝玉石可能具有不同的品质特征及经济价值,其研究有助于珠宝首饰价值的判断,为各国海关执法提供技术支持;另一方面,古代宝玉石产地的确定对了解古代宝玉石的开采与古代科技的发展水平及不同区域的文化交流均具有重要意义。在总结前人研究成果的基础上,结合现代微区测试技术的最新研究成果,从微量元素、包裹体以及同位素分析等方面探讨总结了微区测试技术在确定宝玉石产地来源研究中的应用。当前的研究结果显示,不同的技术方法对确定宝玉石的产地来源均有一定的意义,但宝玉石产地来源的最终确定往往需要依赖更大范围和更深入地对宝石矿床的地球化学进行多技术手段的交叉分析。显然,确定各种不同类型宝玉石产地来源的标型特征及建立相关重要宝石产地的地球化学数据库,是最终解决宝玉石产地来源鉴定问题的关键。 相似文献
4.
为探寻适用于黄土地区海绵城市建设的具有较高强度和防渗性能的路基换填材料,通过对掺入水泥、聚丙烯纤维、膨润土的黄土进行强度和渗透性试验,并基于正交试验和田口方法的信噪比分析,获得了改良黄土各掺量的最优配比方案。结果表明:水泥掺量对改良黄土的无侧限抗压强度影响最显著,聚丙烯纤维掺量和长度对其渗透系数影响最大;改良黄土各掺量的最优配比为聚丙烯纤维长度取12 mm、聚丙烯纤维掺量取0.3%、膨润土和水泥掺量分别取3%和8%;在3、7、14 d养护龄期下,最优配比改良黄土的强度和渗透性能均优于不同配比的石灰改良黄土。改良的黄土各掺量最优配比可为黄土地区海绵城市道路建设中的路基处理提供参考。 相似文献
5.
Progress and Prospect of Statistics and Assessment of Large-scale Natural Disaster Damage and Losses
In June 2014, the "Statistics System for the Damage and Loss of Large-scale Natural Disasters" (SSDLLND) was issued by the Ministry of Civil Affairs and the Office of National Disaster Reduction Committee, which marked that the statistics and assessment of China's catastrophic natural disaster damage and losses formally entered a new stage of institutionalization. On the basis of analyzing the five major international disaster damage and loss assessment systems, including HAZUS-MH, ECLAC, DaLA, EMA-DLA and PDNA, the differences between the “SSDLLND” of China and five major international systems were compared from the statistics and assessment contents and indicators. Combined with the statistics and assessment practices of China’s large-scale disaster damage and losses and the characteristics of international systems in recent years, the future development of the SSDLLND were proposed in three aspects: Enriching and improving the framework of damage and loss statistics content, stepwise improvement of disaster impact assessment methods (such as the ecological capital loss assessment, tourism industry loss assessment due to the disasters, etc.), and improving indicators and parameters of loss statistics. The study has an important practical significance for improving the statistics and assessment system of the damage and loss of major natural disasters and better serving the post-disaster recovery and reconstruction decision-making. 相似文献
6.
Colin C. Ferguson 《Mathematical Geology》1979,11(3):329-336
This paper considers an ellipse, produced by the intersection of a triaxial ellipsoid and a plane (both arbitrarily oriented), and derives explicit expressions for its axis ratio and orientation. The relationship between central and noncentral sections, and the problem of intersection probability, are discussed. The resulting equations have obvious applications in structural geology and optical mineralogy, and in stereological modeling of grain-size and grain-shape distributions. 相似文献
7.
Omer Iqbal Mirza Shahid Baig Shahab Pervez Muhammad Iqbal Siddiqi 《Journal of the Geological Society of India》2018,91(1):57-66
The project area lies in the southern part of the Hazara Kashmir syntaxis. The Hazara Kashmir syntaxis is an antiformal structure. The project area includes Rumbli, Namb, Chatrora, Chachan, Panjar, Barathian and Utrinna areas of Rawalpindi and Sudhnoti districts. The southeastern limb of the Hazara Kashmir syntaxis is imbricated along Punjal thrust, Main Boundary thrust and Riasi fault. The Jhelum fault truncates the western limb of Hazara Kashmir syntaxis. The core of syntaxis comprises of Himalayan molasse deposits. These molasse deposits represent the part of cover sequence of Indian plate. These Himalayan molasse deposits include the Early to Middle Miocene Kamlial Formation, Middle to Late Miocene Chinji Formation, Late Miocene Nagri Formation and Late Miocene Dhok Pathan Formation. The area is highly deformed resulting folds and faults. The major folds in the project area are the Panjar anticline, Barathian syncline, Barathian anticline, Rumbli anticline, Chatrora antiformal syncline and Namb syncline. The folds are either northwest-southeast trending or southwestnortheast trending. The folds are asymmetric, open, and gentle and close in nature. The folds are southwest, northeast or southeast vergent. The Jhelum fault truncates the northeast and northwest trending structures. The folds and faults are the result of northeastsouthwest or northwest-southeast Himalayan compression. 相似文献
8.
A study of septarian concretions from late Cretaceous shale sequences of Texas and northern Mexico reveals complex burial-exhumation histories. First generation concretions and pre-fossilized moulds formed in silty clays before significant compaction occurred. Syneresis cracks developed and were filled by length slow fibrous calcite with a decrease in iron content toward the centre of each vein; in some cases this was succeeded by growth of equant or bladed calcite. Subsequent erosion of enclosing sediment caused collapse and break up of concretions, leaving fragments and some unbroken concretions exposed to encrustation and boring on the sea floor. These were subsequently buried and enclosed in a second generation of concretions, which also developed syneresis cracks. The calcite that filled these latter cracks was generally bladed (sometimes followed by equant calcite) and contains more iron toward the centre of the vein. Differences between the calcite filling first and second generation septarian veins indicates changing diagenetic regimes during burial in the marine environment, without a major shift in diagenetic conditions, such as the introduction of meteoric waters. These conclusions have significant implications to cementation in ancient limestones, which show textural and chemical sequences similar to those present in the septarian concretions described. 相似文献
9.
Prograde destruction and formation of monazite and allanite during contact and regional metamorphism of pelites: petrology and geochronology 总被引：5，自引：1，他引：4
The conditions at which monazite and allanite were produced and destroyed during prograde metamorphism of pelitic rocks were determined in a Buchan and a Barrovian regional terrain and in a contact aureole, all from northern New England, USA. Pelites from the chlorite zone of each area contain monazite that has an inclusion-free core surrounded by a highly irregular, inclusion-rich rim. Textures and 208Pb/232Th dates of these monazites in the Buchan terrain, obtained by ion microprobe, suggest that they are composite grains with detrital cores and very low-grade metamorphic overgrowths. At exactly the biotite isograd in the regional terrains, composite monazite disappears from most rocks and is replaced by euhedral metamorphic allanite. At precisely the andalusite or kyanite isograd in all three areas, allanite, in turn, disappears from most rocks and is replaced by subhedral, chemically unzoned monazite neoblasts. Allanite failed to develop at the biotite isograd in pelites with lower than normal Ca and/or Al contents, and composite monazite survived at higher grades in these rocks with modified texture, chemical composition, and Th-Pb age. Pelites with elevated Ca and/or Al contents retained allanite in the andalusite or kyanite zone. The best estimate of the time of peak metamorphism at the andalusite or kyanite isograd is the mean Th-Pb age of metamorphic monazite neoblasts that have not been affected by retrograde metamorphism: 364.3Dž.5 Ma in the Buchan terrain, 352.9NJ.9 Ma in the Barrovian terrain, and 403.4LJ.9 Ma in the contact aureole. Some metamorphic monazites from the Buchan terrain have ages partially to completely reset during an episode of retrograde metamorphism at 343.1Nj.1 Ma. Interpretation of Th-Pb ages of individual composite monazite grains is complicated by the occurrence of subgrain domains of detrital material intergrown with domains of material formed or recrystallized during prograde and retrograde metamorphism. 相似文献
10.
深部碳酸盐岩油气生成和保存的特征及其模拟实验研究 总被引：9，自引：0，他引：9
塔里木盆地具有地温梯度低和油气藏埋藏深度大的特点，深埋引起的高压利于油藏保存，7000ｍ的地层温度＜１６５℃，低于通常认为石油形成温度上限，油藏保存的深可以达到7000ｍ。铁岭灰岩高温高压模拟实验表明，高压抑制油向气转化。塔里木盆地古生界海相碳酸盐岩晚期二次生烃使生油窗延伸至Ｒｏ１.５%。 相似文献
11.
V. T. Trofimov A. V. Nikolaev A. D. Zhigalin T. A. Baraboshkina M. A. Khar’kina E. V. Arkhipova 《Moscow University Geology Bulletin》2017,72(4):235-244
Onshore oil and gas production is often accompanied by accidents of varying severities and negative consequences. Operations within the areas of peripheral seas and the World Ocean have significantly aggravated the situation and driven a significant part of the emergencies related to the production of hydrocarbons to regional and global levels. The use of new technologies in the production of shale hydrocarbons has added a new problem, that is, the probability of total contamination of a large volume of geological environment with highly toxic chemicals. The discovery of a new promising fossil energy source, gas hydrates, makes it possible only to outline the possible related hazards and shows that the environmental risk can increase by many times. To withstand the threat of emergencies related to the growth of hydrocarbon production, it is advisable to establish special control and rapid-response structures on a nationwide scale. Such structures may be open to international cooperation in the jurisdiction of the United Nations, if necessary. 相似文献
12.
The discrepancy between the impact records on the Earth and Moon in the time period, 4.0-3.5 Ga calls for a re-evaluation of the cause and localization of the late lunar bombardment. As one possible explanation, we propose that the time coverage in the ancient rock record is sufficiently fragmentary, so that the effects of giant, sterilizing impacts throughout the inner solar system, caused by marauding asteroids, could have escaped detection in terrestrial and Martian records. Alternatively, the lunar impact record may reflect collisions of the receding Moon with a series of small, original satellites of the Earth and their debris in the time period about 4.0-3.5 Ga. The effects on Earth of such encounters could have been comparatively small. The location of these tellurian moonlets has been estimated to have been in the region around 40 Earth radii. Calculations presented here, indicate that this is the region that the Moon would traverse at 4.0-3.5 Ga, when the heavy and declining lunar bombardment took place. The ultimate time limit for the emergence of life on Earth is determined by the effects of planetary accretion--existing models offer a variety of scenarios, ranging from low average surface temperature at slow accretion of the mantle, to complete melting of the planet followed by protracted cooling. The choice of accretion model affects the habitability of the planet by dictating the early evolution of the atmosphere and hydrosphere. Further exploration of the sedimentary record on Earth and Mars, and of the chemical composition of impact-generated ejecta on the Moon, may determine the choice between the different interpretations of the late lunar bombardment and cast additional light on the time and conditions for the emergence of life. 相似文献
13.
为解决5000 m地质岩芯钻探基础准则与依据缺失问题，提高钻探装备的自动化、智能化水平，启动了5000 m智能地质钻探技术装备研发工作，通过钻机装备、钻探器具研制，钻探工艺技术研究并经试验示范验证，取得多项创新成果，形成了5000 m地质岩芯钻探技术体系。通过特深孔钻孔口径与管柱规格优化研究、钻杆规格设计、装备性能参数选配，形成了5000 m地质岩芯钻探技术规范体系；基于5000 m特深孔地质岩芯钻机、孔口自动化作业装置等关键设备研制，实现了绳索取芯钻进的孔口作业全流程自动化，形成了轻量化钻机孔口管柱柔顺控制技术；基于复杂地层孔内工况判别、钻进参数优化与轨迹优化控制等技术问题研究，形成了多源信息融合的地面与孔底一体化钻进过程智能控制技术；基于高性能薄壁绳索取芯钻杆和系列小口径高效钻具研制，形成了大深度绳索取芯系列钻杆钻具技术；研发了耐高温环保型冲洗液、生物破胶废浆处理技术、“广谱型”双浆堵漏技术，形成了绿色环保型冲洗液体系与护壁堵漏技术。 相似文献
14.
为解决5000 m地质岩芯钻探基础准则与依据缺失问题，提高钻探装备的自动化、智能化水平，启动了5000 m智能地质钻探技术装备研发工作，通过钻机装备、钻探器具研制，钻探工艺技术研究并经试验示范验证，取得多项创新成果，形成了5000 m地质岩芯钻探技术体系。通过特深孔钻孔口径与管柱规格优化研究、钻杆规格设计、装备性能参数选配，形成了5000 m地质岩芯钻探技术规范体系；基于5000 m特深孔地质岩芯钻机、孔口自动化作业装置等关键设备研制，实现了绳索取芯钻进的孔口作业全流程自动化，形成了轻量化钻机孔口管柱柔顺控制技术；基于复杂地层孔内工况判别、钻进参数优化与轨迹优化控制等技术问题研究，形成了多源信息融合的地面与孔底一体化钻进过程智能控制技术；基于高性能薄壁绳索取芯钻杆和系列小口径高效钻具研制，形成了大深度绳索取芯系列钻杆钻具技术；研发了耐高温环保型冲洗液、生物破胶废浆处理技术、“广谱型”双浆堵漏技术，形成了绿色环保型冲洗液体系与护壁堵漏技术。 相似文献
15.
《Russian Geology and Geophysics》2016,57(9):1342-1348
The study presents assessment of the hydrocarbon potential of almost all known sedimentary basins of the African continent and adjacent offshore coastal areas of the Mediterranean Sea and the Indian and Atlantic Oceans. The assessment is based on new data that became available following the well-known monograph of V.I. Vysotsky et al. (1994), which provided the last petroleum potential assessment published in the Russian literature. These data provide a more accurate evaluation of the regional initially-in-place and recoverable hydrocarbon resources, exploration maturity as of the beginning of 2015, the total number of discovered oil and gas fields, and field/resources distribution by basin type and offshore and onshore areas. 相似文献
16.
火山地层界面的类型、特征和储层意义 总被引：1，自引：0，他引：1
按照火山地层界面的形成过程和地质属性将其划分为5类,分别为喷发整合、喷发不整合、喷发间断不整合、构造不整合和侵入接触,除侵入接触外,其他不整合均可细分为角度不整合和平行不整合两种。喷发整合和喷发不整合两类界面上下岩层的间断为数分钟-数年,并且在界面上下均具有冷凝表壳或细火山碎屑层等,喷发不整合可为平行面状或交织曲面状,多为凹凸不平,分布范围小;喷发间断不整合界面形成时间为数十年-数千年,界面之下冷凝表壳或细碎屑层等明显遭受侵蚀,在横向上存在风化壳-沉积岩夹层的组合形式,界面平面展布多为波状曲面;构造不整合与喷发间断不整合在特征上相似,但形成时间为数千年-数百万年,界面分布范围更大。东北地区中生代火山岩剖面揭示:在喷发整合/不整合界面附近原生孔隙发育,随着与界面距离的增加孔隙度变小;具有交织曲面状界面岩层的面孔率大,孔隙发育带厚度及其占岩层比例均大于平行面状界面岩层。盆内钻井资料揭示喷发间断/构造不整合界面之下发育大量的次生孔隙,可与原生孔隙组合使储层物性变好,但当原生孔隙未能保存时其储层物性变化难以预测。 相似文献
17.
Ten soils from Puerto Rico representing various states of weathering were subjected to engineering index tests, strength and density measurement, mineralogic analyses, and scanning electron microscopy.Engineering classification systems used for temperate soils tend to underestimate the engineering behavior of these undisturbed lateritic soils and in the undisturbed state the soils exhibit low densities and high strengths.The engineering properties of the undisturbed soils show systematic trends in relation to the degree of weathering and the parent rock. For a given rock, the void ratio is decreased and cohesion increased as weathering proceeds. This is the result of increasing crystallization and cementation by the sesquioxides.The specific gravity of the solid particles is a promising index property to characterize these lateritic soils insofar as it reflects iron oxide content. The decrease in void ratio and increase in cohesion with increasing specific gravity suggests a model for the engineering classification of tropical soils. 相似文献
18.
莫霍面是地球内部的最明显的两个一级速度间断面之一,也是地球内部最接近地球表面的全球性分界面,与人类的生存环境关系最为密切,也是最有可能与地表观察的结果相联系。自从莫霍面被发现之后, 在全球性或区域性研究上都备受关注,对其界面性质的确定经过了近一个世纪,相变界面还是化学界面,仍处于争论之中。莫霍面的埋藏深度及其性质的横向不一致,在全球尺度上显示得很明显,大体与地表所见的陆—洋分布相关。本文综述了莫霍面的性质、岩石学特征、地球化学元素分布及其热力学、动力学特征,并讨论了莫霍面与找矿的关系。 相似文献
19.
Mitsunobu Tatsumoto Daniel M Unruh George A Desborough 《Geochimica et cosmochimica acta》1976,40(6):617-634
U-Th-Pb systematics study of Allende inclusions showed that U, Th and Sr concentrations in Ca, Al (pyroxene)-rich chondrules and white and pinkish-white aggregate separates of Allende are five to ten times higher than those of the matrix, whereas Mg (olivine)-rich chondrules have U and Th concentrations about twice as high as the matrix. Th concentrations are extremely high in white aggregates and in pinkish-white (spinel-rich) aggregates while U and Sr concentrations in white aggregates are more than twice as high as those in pinkish-white aggregates. Large enrichment of these refractory elements in the white aggregates indicates that they contain high-temperature condensates from the solar nebula. The Pb concentrations in the inclusions are less than half of those in the whole rock and matrix, indicating that the matrix is a lower-temperature condensate. The isotopic composition of lead in the matrix is less radiogenic than that of the whole meteorite, whereas lead in Ca- and Al-rich chondrules and aggregates is extremely radiogenic. The 206Pb/204Pb ratio reaches as high as 55.9 in a white aggregate separate. The lead of Mg-rich chondrules is moderately radiogenic and the 206Pb/204Pb ratio ranges from 18 to 26. A striking linear relationship exists among leads in the chondrules, aggregates and matrix on the 207Pb/204Pb vs 204Pb/204Pb plot. The slope of the best fit line is 0.6188 ± 0.0016, yielding an isochron age of 4553 ± 4 m.y. The regression line passes through primordial lead values obtained from Canyon Diablo troilite. The data, when corrected for Canyon Diablo troilite Pb and plotted on a U-Pb concordia diagram, show that the pink and white aggregates and the Ca-Al-rich and Mg-rich inclusions have excess Pb and define a chord which intersects the concordia curve at 4548 ± 25 m.y. and 107 ± 70 m.y. The intercepts might correspond to the agglomeration age of the meteorite and a time of probably later disturbance, respectively. The matrix and some chondrules which contain less radiogenic lead did, however, not fit on the chord. The Rb-Sr data of Allende did not define an isochron suggesting that the Rb-Sr system was also disturbed by a later event, as suggested by the U-Pb concordia data. The lowest observed 87Sr/86Sr ratio in Allende inclusions is similar to the initial ratio of the Angra dos Reis achondrite (Papanastassiou, Thesis, 1970).The initial Pb isotopic composition of Orgueil calculated by a single-stage evolution model is more radiogenic than that of Canyon Diablo troilite. To reconcile the U-Pb data of Orgueil and Allende, we propose that the initial lead isotopic composition of the carbonaceous chondrites was slightly different from that of Canyon Diablo troilite Pb. 相似文献