河南省舞阳铁矿田岗庙刘铁矿床的地质特征及构造控矿分析          下载免费PDF全文

刘昭宜 《地质找矿论丛》2012,27(2):180-185

文章从地层、构造、矿体和矿石等方面总结了河南省舞阳铁矿田岗庙刘铁矿床的地质特征,分析了控制铁矿床的地质构造.铁矿床为沉积变质型铁矿,含矿岩系位于新太古界铁山庙组的上、下混合岩段之间;矿床赋存的空间位置严格受地堑和地垒式断块控制;古侵蚀面不整合构造面只使岗庙刘矿床中部矿块的矿石全部氧化,而对东部和西部矿块没有造成很大的影响.  相似文献   

福建建瓯罗山钼矿床地质特征及深部找矿潜力分析   总被引：1，自引：0，他引：1  

钟长华 《福建地质》2012,31(3):224-232

建瓯罗山钼矿产于晚侏罗世黑云母正长花岗岩体内,受北北东—北北西向断裂及次级断裂控制,蚀变上部为硅化-绢云母化,下部为硅化-钾化,矿石类型主要为构造角砾型和石英细脉型。结合成矿地质条件分析认为成矿物质主要来源于隐伏-半隐伏的花岗斑岩,属广义的斑岩型钼矿,深部仍具有较大找矿潜力。  相似文献   

Geologic feature, origin of the Tiantang lead-zinc manganese polymetallic ore deposit in Jian＇ou City, Fujian Province     

《福建地质》2012,31(2)

天堂铅锌锰多金属矿地处闽中裂谷带北段、武夷山成矿带东缘,矿体明显受南北向断裂带及其派生的北东东向断裂构造控制。矿区发现铅锌锰多金属矿体3条,均产于北东东向断裂构造破碎带内。在矿体空间分布上分带明显,具有上锰、下铅锌（银）的特点。初步研究认为矿床属中低温热液成因,成矿物质主要来源于马面山群变质基底,深部铅锌（银）多金属矿的找矿潜力较大。  相似文献   

用角点网格模型表达地质模型的剖析及在油气成藏过程模拟中的应用   总被引：1，自引：0，他引：1       下载免费PDF全文

毛小平  张志庭  钱真 《江苏地质》2012,36(3):265-273

在三维模型表达中,相对于PEBI、径向(Radial)网格而言,角点网格是目前油气田开发研究比较通用的一种三维模型。它在表达复杂断块、油藏非均质性上较为突出。在油气勘探研究中,一般使用常规的面模型来进行各种定量模拟评价,这对于精度要求越来越高的油气成藏过程定量模拟与分析而言,显得精度不够。因此,基于角点网格模型的油气成藏过程的算法研究和应用在勘探评价中显得尤为重要。探讨了角点网格模型的空间信息与属性信息的管理与表达优势,讨论了如何将传统的面模型模拟算法改进成新的角点模型,研究了相应的算法,分析了其中的主要难点及解决方案,其中包括多尺度空间加密、角点网格结构及表达模型的优势、各单元网格岩性属性提取与使用、烃源岩厚度分配、运移网格间的匹配关系等问题,从三维表达、五史(构造史、热史、生烃史、排烃史及运聚史)所遇到的主要问题及解决方案进行了剖析。  相似文献   

川气东送管道工程沿线地质灾害及防治对策分析     

方浩 《中国地质灾害与防治学报》2012,23(3):46-50

川气东送管道工程是国家跨区域重大天然气管网工程,路线全长1559km。管道沿线地质环境条件复杂,地质灾害异常发育。笔者在对沿线地质灾害调查的基础上,开展了地质灾害危险性评估,并提出了具体的对策建议,主要取得了以下认识：1）川气东送管道沿线地貌类型众多、活动构造复杂、岩土体工程地质条件及水文地质条件差异较大,人类工程活动强烈,地质灾害异常发育。2）研究区突发性地质灾害与缓变性地质灾害并存,共发育隐患点260处,其中崩塌88处、潜在不稳定斜坡74处、滑坡52处、地面沉降36处、泥石流10处。3）地质灾害危险性大的地质灾害点共16处,危险性中等的9处,其余为危险性较小的地质灾害隐患点。4）提出了各类地质灾害点的防治对策建议,为管道工程沿线地质环境安全提供了基础地质依据。  相似文献   

Constraints on mechanisms for the growth of gully alcoves in Gasa crater, Mars, from two-dimensional stability assessments of rock slopes     

Chris H. Okubo  Livio L. Tornabene 《Icarus》2011,211(1):207-221

The value of slope stability analyses for gaining insight into the geologic conditions that would facilitate the growth of gully alcoves on Mars is demonstrated in Gasa crater. Two-dimensional limit equilibrium methods are used in conjunction with high-resolution topography derived from stereo High Resolution Imaging Science Experiment (HiRISE) imagery. These analyses reveal three conditions that may produce observed alcove morphologies through slope failure: (1) a ca. >10 m thick surface layer that is either saturated with H₂O ground ice or contains no groundwater/ice at all, above a zone of melting H₂O ice or groundwater and under dynamic loading (i.e., seismicity), (2) a 1-10 m thick surface layer that is saturated with either melting H₂O ice or groundwater and under dynamic loading, or (3) a >100 m thick surface layer that is saturated with either melting H₂O ice or groundwater and under static loading. This finding of three plausible scenarios for slope failure demonstrates how the triggering mechanisms and characteristics of future alcove growth would be affected by prevailing environmental conditions. HiRISE images also reveal normal faults and other fractures tangential to the crowns of some gully alcoves that are interpreted to be the result of slope instability, which may facilitate future slope movement. Stability analyses show that the most failure-prone slopes in this area are found in alcoves that are adjacent to crown fractures. Accordingly, crown fractures appear to be a useful indicator of those alcoves that should be monitored for future landslide activity.  相似文献   

Hypsometry of Titan     

Ralph D. Lorenz  Elizabeth P. Turtle  Alice Le Gall  Oded Aharonson  Ellen Stofan 《Icarus》2011,211(1):699-706

Cassini RADAR topography data are used to evaluate Titan’s hypsometric profile, and to make comparisons with other planetary bodies. Titan’s hypsogram is unimodal and strikingly narrow compared with the terrestrial planets. To investigate topographic extremes, a novel variant on the classic hypsogram is introduced, with a logarithmic abscissa to highlight mountainous terrain. In such a plot, the top of the terrestrial hypsogram is quite distinct from those of Mars and Venus due to the ‘glacial buzz-saw’ that clips terrestrial topography above the snowline. In contrast to the positive skew seen in other hypsograms, with a long tail of positive relief due to mountains, there is an indication (weak, given the limited data for Titan so far) that the Titan hypsogram appears slightly negatively skewed, suggesting a significant population of unfilled depressions. Limited data permit only a simplistic comparison of Titan topography with other icy satellites but we find that the standard deviation of terrain height (albeit at different scales) is similar to those of Ganymede and Europa.  相似文献   

Time-resolved studies of hypervelocity vertical impacts into porous particulate targets: Effects of projectile density on early-time coupling and crater growth     

Brendan Hermalyn  Peter H. Schultz 《Icarus》2011,216(1):269-279

The depth and duration of energy and momentum coupling in an impact shapes the formation of the crater. The earliest stages of crater growth (when the projectile transfers its energy and momentum to the target) are unrecoverable when the event is described by late stage parameters, which collapse the initial conditions of the impact into a singular point in time and space. During the coupling phase, the details of the impact are mapped into the ejecta flow field. In this experimental study, we present new experimental and computational measurements of the ejecta distribution and crater growth extending from early times into main-stage ballistic flow for hypervelocity impacts over a range of projectile densities. Specifically, we assess the effect of projectile density on coupling depth and location in porous particulate (sand) targets. A non-invasive high-speed imaging technique is employed to capture the velocity of individual ejecta particles very early in the cratering event as a function of both time and launch position. These data reveal that the effects of early-stage coupling, such as non-constant ejection angles, manifest not only in early-time behavior but also extend to main-stage crater growth. Time-resolved comparisons with hydrocode calculations provide both benchmarking and insight into the parameters controlling the ejection process. Measurements of the launch position and metrics for the transient diameter to depth ratio as a function of time demonstrate non-proportional crater growth throughout much of excavation. Low-density projectiles couple closer to the surface, thereby leading to lower ejection angles and larger effective diameter to depth ratios. These results have implications for the ballistic emplacement of ejecta on planetary surfaces, and are essential to interpreting temporally resolved data from impact missions.  相似文献   

The dispersal of pyroclasts from Apollinaris Patera, Mars: Implications for the origin of the Medusae Fossae Formation     

Laura Kerber  James W. Head  François Forget 《Icarus》2011,216(1):212-220

The Medusae Fossae Formation (MFF) has long been thought to be of Amazonian age, but recent studies propose that a significant part of its emplacement occurred in the Hesperian and that many of the Amazonian ages represent modification (erosional and redepositional) ages. On the basis of the new formational age, we assess the hypothesis that explosive eruptions from Apollinaris Patera might have been the source of the Medusae Fossae Formation. In order to assess the likelihood of this hypothesis, we examine stratigraphic relationships between Apollinaris Patera and the MFF and analyze the relief of the MFF using topographic data. We predict the areal distribution of tephra erupted from Apollinaris Patera using a Mars Global Circulation Model (GCM) combined with a semi-analytical explosive eruption model for Mars, and compare this with the distribution of the MFF. We conclude that Apollinaris Patera could have been responsible for the emplacement of the Medusae Fossae Formation.  相似文献   

The effect of sub-pixel slope variations on photoclinometry     

Richard Greenberg  Marita Morris 《Icarus》2011,214(1):348-350

Sub-pixel slope variations can have significant effects on the intensity of light scattered from a planetary surface. As a result, determination of the surface slope from the apparent brightness of a given pixel can be confounded by uncertainly in such variations. Under a wide range of conditions, the average slope across the pixel may be different from what is inferred by photoclinometry. Because topography is derived from photoclinometry by integrating the slope across an image composed of many pixels, topographic elevation could in principle be distorted considerably by this effect. As actually applied, photoclinometry generally includes strategies designed to mitigate these effects substantially. Nevertheless, the potential always exists for unknown variations in the character of sub-pixel topography (among other uncertainties such as albedo variations) to introduce errors. The results shown here show the importance of the mitigating strategies and of considering the magnitude of uncertainties in determination of topography.  相似文献