共查询到20条相似文献，搜索用时 15 毫秒
1.
松辽盆地南部大布苏地区青山口组高频层序沉积微相分析与岩性圈闭预测 总被引：2，自引：1，他引：1
松辽盆地大布苏地区的斜坡背景与青山口组一段、二段侧向发育的三角洲前缘砂体配合,具备形成构造—岩性圈闭的良好条件。运用高分辨率层序地层分析方法,将研究层段划分为9个砂组。通过沉积微相分析,确定研究区发育三角洲前缘、浊积扇和半深湖等沉积相类型,并进一步识别出分流河道、河口坝、席状砂、浊积水道、浊积席状砂和半深湖泥质沉积等微相类型。以高频层序划分的砂组为单元,分析了各砂组的沉积微相构成与分布特征,指出垂向上高频层序下降半旋回的砂组,河口坝较发育;上升半旋回的砂组,分流河道较发育;青一段、青二段中,下部砂体厚度大,上部砂体厚度薄。平面上砂体呈南西—北东方向展布,西南部三角洲前缘水下分流河道、河口坝、席状砂等砂体发育;东北部以半深湖泥质沉积为主,局部发育浊积扇;砂体向北西斜坡方向的侧向减薄、尖灭明显。研究认为,三角洲前缘砂体与斜坡背景上的鼻状构造背景相互匹配,易于形成构造—岩性圈闭,为研究区最有利的勘探领域;结合地震特征,进一步预测了3个岩性圈闭勘探目标。 相似文献
2.
青藏高原西部甜水海地区白垩纪花岗岩类的岩石学地球化学特征及其地质意义 总被引：2，自引：0，他引：2
甜水海地区广泛分布白垩纪的中酸性侵入岩,可分为早白垩世（123Ma）、晚白垩世早期（100~93Ma）和晚白垩世晚期（79~74Ma）3期。早期侵入体零星,为正长花岗岩、二云母花岗岩及含石榴子石花岗岩,属高钾钙碱性系列,A/CNK大于1.1,K2O含量大于Na2O,负Eu异常明显,刚玉分子数大于1.1,属于典型的强过铝质S型花岗岩。晚白垩世早期花岗岩分布广泛,以英云闪长岩和花岗闪长岩为主,主要属中—高钾钙碱性系列,个别属于钾玄岩系列,A/CNK主体小于1.15,负Eu异常中等,刚玉分子数多小于1.1,主体属I型花岗岩。晚白垩世晚期花岗岩同样分布广泛,为花岗闪长岩、二长花岗岩组合,主要属于高钾钙碱性系列,个别为中钾钙碱性系列,A/CNK主体大于1.05,负Eu异常较明显,刚玉分子数多大于1.1,主体属于典型的S型花岗岩。综合分析认为,甜水海地区白垩纪中酸性侵入岩与班公湖-怒江残余洋盆消减、闭合有关,可能记录了羌塘-冈底斯带之间的同碰撞（早期）、碰撞后（晚白垩世）等构造岩浆演化过程。 相似文献
3.
西北地区侏罗系的三角洲沉积 总被引：16，自引：0，他引：16
西北地区侏罗广泛发育扇三角洲,辫状河三角洲和曲流河三角洲相沉积,其中扇三角洲与陡倾的盆地边缘有关,盆地的沉降速率大于沉积率,沉积层序为加积型,并以沉积物重力流和无河道片流区同搬运的沉积短斩泄荷为特征,辫状河三角洲与不很陡的盆地边缘梯度有关,其沉积速率大于盆地的沉降速率,沉积层序为进积型,并以河道径流广泛发育为特征,曲流河三角洲与缓坡陷型构造边界有关,并具有以河流作用为主,湖泊作用的辅的特征,３种三 相似文献
4.
根据地震信息,尝试划分了轻微、中等及强烈等三种不同程度的正、负反转构造样式,以不同实例论述了这些构造样式的性质与演化模式。构造反转对油气聚集一般是有利的,但也有可能发生不利影响。正反转构造中,以中等正反转构造样式最有利于油气聚集,反转太强烈时,容易破坏圈闭结构;负反转构造中可常见风化壳储层,为油气储集创造有利条件。 相似文献
5.
Volcanogenic massive sulfide deposits in ophiolite complexes are usually attributed to the Cyprus type. They associate with
basaltic volcanics that are formed in mid-ocean or back-arc spreading centers and much less frequently in intra-plate settings.
The deposits are characterized by copper or copper-zinc ores that are enriched in Ni, Co, and in places Mn and As, but are
very poor in Pb and demonstrate a low to moderate content of Ag and Au. Typically, the deposits are low to very low in ore
and metal reserves. Cyprus-type deposits were irregularly distributed during geological history. The most ancient of them
were formed in the Neoproterozoic, while the bulk of the deposits are Ordovician or Cretaceous in age. Their possible Paleoproterozoic
analogues can be found in the Svecofennian belt (Outokumpu ore district), while modern ones are confined to the Explorer and
Endeavour Ridges and southern segment of the Juan de Fuca Ridge. 相似文献
6.
青海省都兰县八道班一带侵入岩的岩性为石英闪长岩至正长花岗岩的岩浆演化序列,其空间具有北西-南东向带状分布的特点,为准铝质、高钾、钙碱性镁质花岗岩;稀土总量REE中等,轻重稀土分异和轻稀土分馏强烈;大离子亲石元素(LILE)Rb、K等相对富集,Ba、Sr等相对亏损;高场强元素(HFSE)Th、Hf等相对富集,Nb、Ta、Ti等相对亏损,且由石英闪长岩→花岗闪长岩→二长花岗岩→正长花岗岩演化,相对富集和相对亏损的程度逐渐增强;源岩以壳源为主,亦有幔源物质加入,属壳-幔混合型花岗岩。岩石具"C"型高硅埃达克岩特征。其锆石U-Pb同位素年龄在237~224Ma之间,侵位时代为晚三叠世;其成因是印支晚期西秦岭构造单元向柴达木东南缘斜向俯冲的产物。本区发现埃达克质岩对于与埃达克岩有关斑岩铜矿成矿规律的研究和找矿意义重大。 相似文献
7.
I. A. Pérez M. L. Sánchez M. A. García N. Pardo 《International Journal of Environmental Science and Technology》2017,14(3):653-662
Calculating air mass trajectories is common in atmospheric analyses. However, if explainable results are to be achieved, several procedures are needed to process the vast amount of information handled. Clustering methods are statistical tools usually considered for such a purpose. Although they are based on rigorous algorithms, certain questions still remain when these methods are applied. The current review is organised in sections according to the sequence followed by such procedures. First, the types of clustering methods are described, with their core being the distance used. One key point is the stopping rule, which determines the final number of clusters. A simple classification based on this number is then suggested. Finally, the graphical presentation of the results is examined and the main drawbacks are commented on. A range of applications and results are considered to illustrate each section, and certain caveats and recommendations are also presented. 相似文献
8.
Large cokriging systems arise in many situations and are difficult to handle in practice. Simplifications such as simple kriging,
strictly collocated and multicollocated cokriging are often used and models under which such simplifications are, in fact,
equivalent to cokriging have recently received attention. In this paper, a two-dimensional second-order stationary random
process with known mean is considered and the redundancy of certain components of the data at certain locations vis-à-vis
the solution to the simple cokriging system is examined. Conditions for the simple cokriging weights of these components at
these locations are set to zero. The conditions generalise the notion of the autokrigeability coefficient and can, in principle,
be applied to any data configuration. In specific sampling situations such as the isotopic and certain heterotropic configurations,
models under which simple kriging, strictly collocated, multicollocated and dislocated cokriging are equivalent to simple
cokriging are readily identified and results already available in the literature are obtained. These are readily identified
and the results are already available in the literature. The advantage of the approach presented here is that it can be applied
to any data configuration for analysis of permissible simplifications in simple cokriging. 相似文献
9.
Abdullah Arik 《Geotechnical and Geological Engineering》1990,8(4):305-318
Summary Reliable ore reserve estimates for deposits with highly skewed grade distributions are difficult tasks to perform. Although some recent geostatistical techniques are available to handle problems with these estimations, ordinary kriging or conventional interpolation methods are still widely used to estimate the ore reserves for such deposits. The estimation results can be very sensitive to the search parameters used during the interpolation of grades with these methods.This paper compares the ore reserve estimates from ordinary kriging using several cases in which certain search parameters are varied. The comparisons are extended to different mineralizations to show the changing effects of these parameters. 相似文献
10.
小秦岭金矿产于新太古界太华群变质岩中,其中的次级拆离断裂为赋矿构造。为了探究矿床的地球化学特征和矿床成因,从矿区主要地质体采集了100件来自太华群地层、文峪岩浆岩和矿石的样品进行测试,其稀土元素的主要特征为：太华岩群的ΣREE值为30.81×10-6~188.66×10-6;δEu值为0.62~1.24;花岗岩和脉岩类ΣREE值为58.22×10-6~365.98×10-6;δEu为0.90~1.10;矿石的ΣREE值多集中于76.74×10-6~358.22×10-6,δEu值多集中于0.74~1.14。结果表明：各地质体稀土总量接近,没有Eu异常或有微弱的正、负铕异常;矿石的稀土元素含量特征与太华群接近,而与文峪等花岗岩相差较远。分析认为,成矿物质主要来源于太华群地层而不是花岗岩。 相似文献
11.
R.W.G. Carter 《Sedimentary Geology》1982,33(1):35-56
Mixes of carbonate and quartz sands, which are commonly encountered in Recent coastal sediments, require careful analysis if they are to be correctly interpreted. Grain-size data fall into multimodal or segmented zig-zag distributions which may require some kind of component separation if they are to be summarised by conventional statistics, and before they can be assigned to a particular hydrodynamic depositional process or environment. Unfortunately, separation techniques are only spasmodically applied, usually without due regard to the consequences. Such artificially filtered or truncated distributions are of little subsequent use. Using a range of samples from two beaches in NW Ireland, where carbonate proportions range from nearly zero to over sixty percent, the interrelationships of the two dominant components were examined. Where only a small carbonate proportion is incorporated into a large quartz one, predictable modifications of the size-curve are apparent. However, the components are more independent if mixtures are near equal. The occurrence of a number of distinctive combinations of simple straight lines and complex zig-zag curves probably reflects the relatively dynamic nature of the carbonate fraction. 相似文献
12.
E. S. T. O'Driscoll 《Mineralium Deposita》1981,16(1):85-101
In plots of symbolised geo-data which have variations in density of symbol population, structural corridors are defined by relatively narrow belts in which the density of symbol population is in marked contrast to that of surrounding areas. Some corridors are of high population density (HPD), some of low population density (LPD), whilst others are serial composites. In geology, corridors are to be seen in ancillary plots of gravimetrics, magnetics, photolineaments, Landsat lineaments and allied data. Those related to ore deposits are commonly 100–200 km in length, with aspect ratios (length/breadth) from 20 to 40. They are distinguished from conventional anomaly trends by not necessarily defining absolute highs or lows in individual symbol measurements. Rather do they reflect dislocations in the pattern of material distributions which the symbols represent, and are therefore related more to gradient functions. They must be distinguished from random trends which pervade ordinary patterns of material distributions. Corridors defined for the one area by different sets of geo-data frequently do not coincide, and this is anticipated by differences in the particular qualities measured, and the geological times at which these qualities were established. Field observations show structural corridors to correspond to subsurface dislocations, and, depending on the type of geological environment, either edges or centres of corridors are significantly related to mineral and oil deposits. In airphoto and Landsat lineament plots, the best data for revealing corridors are the smaller features at the high frequency end of the symbol dimensional range. In such cases, structural corridors are hard to preconceive, and emerge only after the assembly of data is complete. This greatly reduces the problem of subjectivity of the interpreter. Photolineament corridors in the Kalgoorlie goldfield of Western Australia are discussed and compared with Landsat corridors related to metal and oil occurrences in North America. 相似文献
13.
三河口水利枢纽是引汉济渭工程两大水源工程之一,边坡岩体变形特性是主要的岩石力学问题,为此用刚性承压板法和钻孔变形试验,针对坝肩边坡不同岩性、不同风化程度岩体开展了大量原位试验。综合分析92个点刚性承压板变形试验成果,获得了不同岩体变形参数范围,重点讨论了不同变形曲线类型、各因素对试验成果的影响。介绍了钻孔变形试验方法及原理,分析了坝肩边坡岩体钻孔变形试验成果,最后对两种方法的变形试验进行对比,并综合评价了边坡岩体的变形特性。结果表明,该工程坝肩边坡岩体具有较高的变形参数,变形曲线大部分为直线型,岩体变形特性与岩体类别密切相关,两种试验方法所得岩体变形参数总体趋势一致。 相似文献
14.
Lamellar structures in low-calcium orthopyroxenes 总被引：1，自引：0，他引：1
James N. Boland 《Contributions to Mineralogy and Petrology》1974,47(3):215-222
Clinoenstatite lamellae are found to be distributed in three distinct patterns that define three microstructural types. There are regions of the crystal devoid of lamellae and these correspond to ordered or O-orthopyroxene. When the lamellae are present but not in any periodic arrangement, disordered or D-orthopyroxene is identified. In some areas, the lamellae are spaced periodically and these are regions of “superlattice” orthopyroxene. These microstructural types explain all previous X-ray results on orthopyroxenes. Microstructural differences between low and high calcium orthopyroxenes are discussed. 相似文献
15.
Although the elderly are commonly thought to be disproportionately vulnerable to natural hazards, the elderly populations of coastal communities are continuing to grow. Because there is little to no empirical hazards work specifically addressing the vulnerable elderly in coastal communities, this paper uses Sarasota County, Florida, as a case study to analyze how vulnerable the elderly are to hurricane hazards and whether all elderly people are equally vulnerable. To explore the spatial variations in degree and composition of vulnerability among this population, the analysis maps physical exposure to hurricane storm-surge inundation and precipitation-induced flooding and creates social vulnerability indices by applying principal components analysis to census block group data in a geographic information system. The results show that elderly inhabitants of barrier islands face a considerable physical threat from hurricane-induced storm surge and flooding but are less socially vulnerable because of their wealth; the elderly living inland are far less physically vulnerable but are poorer and consequently demonstrate high socioeconomic sensitivity and limited adaptive capacity to these hurricane hazards. The paper concludes that the elderly are not equally vulnerable: there are many different types of elderly living in many different locations, and their vulnerability varies by type and over space. Effective vulnerability reduction measures should account for these differences between the elderly populations. 相似文献
16.
17.
Indonesia has abundant coal resources at depths suitable to contain substantial volumes of naturally occurring methane, which are currently being explored. Most Indonesian coals are thermally immature, but are composed of hydrogen-rich organic components that are presumed to make them excellent substrates for biogenic methane production. Gas isotope results from pilot wells in South Sumatra, reported in this study, are interpreted to indicate biogenic origins for the methane. Corresponding formation water samples were collected and incubated, and show the presence of indigenous microbial communities capable of producing methane from Indonesian and Australian coal. Although these results are only preliminary, they are promising and support the possibility of Indonesia developing bio renewable energy from coal seams. 相似文献
18.
混合沉积和混积岩的讨论 总被引：36，自引：6，他引：30
混合沉积物是指陆源碎屑与碳酸盐(包括异化粒等)在沉积上的混合。混合沉积可分为狭义的和广义的,狭义的是指陆源碎屑与碳酸盐组份的混合(在同一岩层内),而广义的混合则包括了狭义的和陆源碎屑与碳酸盐层构成交替互层或夹层的混合。混合沉积很早就引起了人们的注意,尽管碎屑岩和碳酸盐岩的研究与应用已很成熟,但对混积岩的研究多被忽视了。对狭义的混合沉积物有必要起一成因名称——混积岩。当人们接触到混合沉积时,除了分析研究它们的组分和结构特征外,还必须去思考,它们为什么能经常频繁地交互出观,或是直接混合在一起?倒底是：①陆源碎屑跑到碳酸盐的沉积背景里?②碳酸盐跑到陆源碎屑的沉积背景里?③二分别从各自的源地跑到第三种沉积背景里?还是④二本来就在同一沉积背景里?接下来就要思考是什么动力条件使它(们)能从这个沉积背景(环境)“跑”到另一个沉积背景(环境)里去?是水?是风?是自身?还是别的什么力量?那么,又是怎样的水动力或风动力条件呢?是正常条件,还是突发事件?很明显,要分析研究混合沉积和混积岩。这些问题就不得不细细加以考虑,深入进行研究。 相似文献
19.
Günther R. Drevin 《Mathematical Geology》2006,38(7):871-890
A number of subjective and objective methods have been proposed to determine the roundness of rock particles, roundness being
one of three properties describing the shape of a particle.
Methods that make use of the Fourier transform of the polar coordinates of particles’ edge elements are proposed in this paper.
Lowpass filters are used to smooth the profiles of rock particle, roundness is then determined from the differences between
the original and smooth profiles. Further methods that are proposed make use of different measures of inequality to quantify
the distribution of the energy among the transform coefficients of the profiles of rock particles. These values are then used
to determine the roundness of the particles. Entropy and Emlen’s modified entropy are the measures of inequality that are
used. Different methods of determining the centre point of a particle and different methods to interpolate the edge elements
are compared. The sensitivity of the methods to different resolutions is also investigated.
The results obtained with the proposed methods are comparable to those obtained with an existing Fourier transform based method,
however it is shown that the proposed methods are computationally less demanding. It is also shown that the proposed methods
are better than the existing method when the comparison is based on the correlation between the mean roundness of samples
of particles and the actual roundness of the particles. 相似文献
20.
庐枞盆地中发育一些大中型硫铁矿床,曾长期被认为是与次火山岩有关的中低温热液成因。本文从矿床层控特点、矿体形态产状、矿石沉积组构、矿物组合及其生成顺序、矿化分带、包裹体及同位素地球化学等诸方面,证明它们具显著的火山喷气沉积成因特征,并受到后期热液叠加改造。提出了大鲍庄式陆相火山喷气沉积-热液叠加改造型硫铁矿的成矿模式。 相似文献