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1.
《International Geology Review》2012,54(10):1218-1225
Copper deposits of Cuba belong to the Jurassic lead-zinc-copper, Cretaceous copper and Paleogene copper complexes, which differ substantially in their formation conditions. The island is differentiated into a number of metallogenic zones formed at the initial and early stages of the Cuba folded province. Pinar del Rio, Pinos, Trinidad and Oriente zones, of an intrageanticlinal nature, are prospective with respect to copper vein deposits of the lead-Zinc-copper complex. The Sasa and Cauto zones - intrageosynclinal - are prospective with regard to copper-pyrite and copper vein deposits of the Cretaceous complex. A metallogenic study of the island is indicated in planning the exploration of its copper prospects. -- AGI Staff. 相似文献
2.
Using the database of automatic hydrometeorological stations, installed in the Don RIver delta and Taganrog Bay seashore, the sources of the anomalois scale water negative surge and salinization of the Azov Sea under conditions of low river flow in 2015–2016 are studied. The new schemes of stratification and advection of salty sea waters in the Don River mouth under different weather conditions, water discharge and levels are given. 相似文献
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This work presents the results of a study of the biogeographical distribution of Late Albian-Maastrichtian ammonites, found in sequences of the Pacific coast of Russia. The taxa typical of the Pacific Realm were identified, and their distribution traced beyond the borders of this region. In addition, species-migrants, distributed within the studied area were established. As a results of our works, a high level of endemism of ammonite fauna of the East of Russia was noted (75–88% of endemic species, on average). The bipolarity, previously established in the distribution of ammonoids within the Pacific Paleobiogeographical Realm, as well as their high regional provincialism, was confirmed. The following division of the studied area into faunal ammonite provinces in the Late Cretaceous was proposed: Arctic Province; Boreal-Pacific Province, including northeastern Russia (Chukotka Peninsula, the Koryak Upland, Penzhyna Gulf) and the boreal coast of North America (Alaska Peninsula, Arctic Canada and British Columbia); Northwest Pacific Province, including the Primorye Territory, Sakhalin and Shikotan Islands, the Japanese Islands; Northeast Province of the Pacific (the western coast of the United States and Mexico); Southwest Pacific (Australia, New Zealand, Oceania) and Southeast (the western coast of South America and Antarctica, Seymour and James Ross Islands) Provinces. This division is confirmed by data on inoceramid species. In addition, levels of global transgressions and general sea level rise, associated with the appearances of most of widespread marine taxa in the Pacific shelf seas, are established. These include Late Albian, Cenomanian-Turonian boundary, Late Coniacian, Late Campanian, Early-Late Maastrichtian boundary. Moreover, migration of ammonites occurred due to the Tethys Ocean extension and followed the northern sea straits in the Arctic Ocean and within the Pacific Realm, depending on warm currents. Both the counter and one-way migrations were established. 相似文献
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《International Geology Review》2012,54(12):1428-1439
The author suggests a hypothesis of multistage evolution of the mobile crust zones of the Earth, taking into consideration the type of crustal columnar section (oceanic, intermediate, continental, and orogenic), the history of tectonic and magmatic epochs (Caledonian, Hercynian, Kimmeridgian, and Alpine), and the factor of lineament type mobile zones existing during long periods of geological history and contributing to the activation of magmaticprocesses. --E.A. Alexandrov. 相似文献
6.
含瓦斯煤孔隙率和有效应力影响因素试验研究 总被引：1，自引：0，他引：1
以孔隙率基本定义和力学平衡原理为出发点,充分考虑由煤层瓦斯的吸附膨胀和解吸收缩、温度效应的热胀冷缩和煤体骨架受孔隙瓦斯压力的压缩共同引起的本体变形,建立了在压缩条件下(扩容前)的含瓦斯煤孔隙率动态演化模型和以吸附热力学参数及瓦斯压力表达的有效应力方程,并分别根据现场实测孔隙率数据和含瓦斯煤三轴应力试验数据,对所建立的理论模型进行了验证。结果表明,理论计算值与实测资料和试验结论一致性较好,理论模型拟合精度较好,误差不大,所得结论对煤层气开采和矿井瓦斯灾害防治具有一定的指导意义。 相似文献
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《International Geology Review》2012,54(11):1279-1297
The Paleozoic tectonic evolution of Hsieh-fen-shan, western Hunan, belongs to the Caledonian and Hercynian tectonic cycles. The base of the lower Paleozoic group is defined by a geographical unconformity; the Sinian system unconformably overlies the Pan-ch'i group of the Proterozoic. The Hsieh-fen movement represented by this unconformity had not transformed this area into a platform. The lower Paleozoic group may be divided into four structural stages: Lower Sinian, Upper Sinian-Cambrian, Lower Ordovician and Middle Ordovician-Silurian. These stages are represented by the corresponding sedimentary formations: lower terrigenous elastic formation, siliceous and carbonate rocks intercalated with shale, flush formation and upper terrigenous elastic. Due to the absence of magmatic activity it is believed to be of the miogeosyncline type. In the Variscan cycle this area was already consolidated and partly covered with upper Paleozoic neoplatform sediments. Hereditary characters of the early Paleozoic tectonic evolution are obvious. According to the isopachous maps there occurred a strong tectonic differentiation at the end of the Cambrian. In Early Ordovician a northeast extended flysch geosyncline formed, and to the west of it, an uplifted denudation region. The eastern part of the uplifted region rose strongly, in parallel with the flysch geosyncline and with similar dimensions, and may be considered a geanticline. The geosyncline and geanticline have asymmetrical forms, their neighboring flanks being steeper than their opposite ones. Consequently the existence of a so-called pre-Sinian Hsieh-fen axis has not been proved and the boundaries of the Southwestern Platform with the adjoining southeastern Caledonian fold may be located approximately along T'ao-yuan, Yuan-ling Chen-chi, Hsin-Hua and Ch'ien-yang. – Authors. 相似文献
8.
考虑核电厂地基-基础的动力相互作用,应用显式动力有限差分法分析了地震作用下极软岩、较软岩、坚硬岩上核电厂建筑结构基础的地震响应特征,比较了岩石坚硬程度对基础加速度反应谱的影响。研究表明：随着岩石坚硬程度的提高,核电厂建筑物结构基础的地震响应有增加的趋势;在周期轴上,基础处的加速度反应谱曲线会随着岩石坚硬程度的提高逐渐向短周期（高频段）方向移动。在高频段,建造于较坚硬岩石上基础结构的加速度反应谱值偏大;在中等频段,建造于较软岩石上基础结构的加速度反应谱值偏大;在低频段,岩石坚硬程度对加速度反应谱的影响不显著。 相似文献
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基于南中国海东沙海域某地震剖面资料,利用Basin2二维模拟软件,结合研究区有关地温场、热流探测资料和ODP184航次调查的岩心数据,重塑了研究区沉降史、有机质生烃史、古地温场与热史变迁。进而利用“生物成因天然气水合物成藏动力学模拟系统”(Hydrate Dynamics)软件,模拟了水合物聚集的过程与分布范围。模拟结果表明,研究区水合物稳定域较厚(200~250 m),有机质含量适中,生物成因甲烷主要在海底1 km以浅范围内形成。稳定域之下早先埋藏的沉积物中有机质形成的生物成因甲烷在压实流的作用下能够向浅部层位中运移聚集,从而对现在的矿层有所贡献。水合物主要赋存于稳定域底部以上50 m的层位内,富集带中水合物的平均含量约为5%。 相似文献
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沉管隧道基槽爆破施工对既有堤岸稳定性影响的数值仿真分析 总被引：1，自引：0，他引：1
结合爆破数值模拟中爆破荷载的特点,分析了各种荷载施加方法的特点及爆破震动场模拟的要求,基于圣维南荷载等效原理,提出了爆破荷载的等效施加方法,即将作用在炮孔壁上的爆破荷载等效后,施加在同排炮孔中心线或者面上来模拟爆破荷载的作用。结果表明,等效施加方法在近区存在一定差异,但在中远区吻合得较好。利用该等效荷载施加方法,采用三维实体模型计算分析了某沉管隧道基槽爆破施工对既有堤岸稳定性影响,计算了周围不同位置、不同深度位置处的振动响应,并在此基础上,分析研究了减小爆破振动对既有结构物影响的减振措施,可为类似工程提供借鉴。 相似文献
11.
Reaction of zoning of garnet 总被引：1，自引：0，他引：1
Timothy P. Loomis 《Contributions to Mineralogy and Petrology》1975,52(4):285-305
Compositional zoning of garnet in metamorphic or igneous rocks preserves evidence of the equilibration history of the sample and can be interpreted in terms of a growth-fractionation, diffusion-exchange, or diffusion-reaction model. Diffusion zoning is usually assumed to result from exchange reactions between garnet and other phases as the partitioning coefficient varies in response to changing environmental conditions, primarily temperature. However, in many natural environments where garnet grew originally in divariant equilibrium with other phases, changing conditions can promote continuous or “divariant” reactions and consequent compositional shifts of phases that can be much greater in some systems showing these reactions than those related to the small changes of partitioning. Diffusional zoning related to overstepping of these continuous reactions must be related to incongruent reaction and necessitates formulation of a kinetic diffusion-reaction model involving moving phase boundaries as well as solid-state diffusion. Three samples containing zoned garnets from the metamorphic aureole around the Ronda ultramafic intrusion in southern Spain are used to illustrate two possible models of diffusion-reaction processes. The examples are particularly informative because the reactions are demonstrably irreversible and evidence of the reaction system is preserved. Partitioning data indicates that compositions of product phases are not in equilibrium with the original garnet and do not vary with extent of reaction; therefore, exchange reactions with garnet were not possible and garnet changed composition only by incongruent reaction. After a small amount of reaction, Mg/Fe of the rim composition approaches a value apparently in equilibrium with product phases, but the garnets are zoned inward to the original garnet composition preserved in the interior. Grossularite content is approximately constant and spessartite content variable but small, thus, the rim composition of pyrope or almandine is assumed to be fixed by the external reaction process and is taken as a boundary condition in the following models. The zoning profile of pyrope or almandine component between the fixed rim and core compositions (assumed to extend to ∞) is described in semiinfinite, half-space models appropriate for large garnets with narrow rims. The first model corresponds to a reaction system in which all garnet compositions are metastable (case 1) and zoning depends on the independent variables of the diffusion constant, velocity of the interface between garnet and matrix, and time. The second model, corresponding to systems in which the initial garnet composition is metastable but an equilibrium composition is stable (case 2), depends on the independent variables diffusion constant, time, and a function of reaction compositions. In case 1 the consumption velocity is assumed constant and a steady state zoning profile is reached at large time, whereas, in case 2, the velocity decreases with the concentration gradient and steady state is not possible. The models were tested using a reaction time estimated from cooling models of the aureole, mass of garnet consumed, determined petrographically, and phase compositions. The two cases are somewhat independent in that different parameters are independent variables. The estimate of the diffusion constant of 10?18±2 cm2/sec (assumed to be a mutual or binary coefficient for almandine and pyrope) is considered reasonable for the temperature range of reaction (probably 600–900° C), and the two models are consistent considering the probable error and possible real temperature differences. It is obvious that details of the metamorphic reaction system must be known to successfully apply diffusion models. Kinetic models, involving consumption or growth of the phase as well as diffusion are probably necessary when dealing with natural rocks. Several possible and interesting complications, such as cross coupling between components, can be investigated if more data were available. Experimental determination of diffusion constants allow natural reaction rates to be estimated by this method. Diffusion zoning is an important consideration that could increase the efficiency of experimentation with chemically recalcitrant phases. 相似文献
12.
结合工程勘察实践及现场载荷试验成果,提出将珊瑚砂分为海洋类珊瑚砂和濒海类珊瑚砂两大类,并在此基础上对珊瑚砂进行了规范定名,通过现场载荷试验对各类珊瑚砂的岩土力学特性进行了研究分析,阐明了各类珊瑚砂的岩土力学特性,对今后进一步研究珊瑚砂的岩土力学特性及工程实践具有一定指导意义. 相似文献
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铜精矿成分分析是判定其品质的重要手段,尤其是主元素铜的分析。目前,测定铜精矿中铜含量的主要分析方法有碘量法、电感耦合等离子体发射光谱法（ICP-OES）、火焰原子吸收光谱法（FAAS）、X射线荧光光谱法（XRF）、电解重量法等。为确保检测标准量值统一、准确、可靠,本文组织开展了铜精矿中铜镁铅锌的测定实验室间比对活动。通过对参加实验室的检测结果进行统计分析,评价参加实验室对铜精矿中铜镁铅锌测定的技术水平和能力。结果表明：大部分实验室的检测结果为满意,铜精矿中铜的满意率为92.9%,满意率较高;铜镁铅锌的满意率平均值为89.0%。少数实验室出现离群值主要在于样品前处理、检测人员对检测方法未能充分理解并熟练掌握、仪器状态等其他相关因素。碱浸法因样品分解不完全,不能作为铜精矿前处理方法;碱熔法因工序繁琐,易产生基体干扰,不适合作为铜精矿前处理方法。本文建议优先采用酸溶-滴定法测定铜精矿中的铜,而采用酸溶ICP-OES法测定铜精矿中的铜镁铅锌,该方法高效快捷,但其稳定性需要进一步的实验考察。 相似文献
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Spheres of discharge of springs 总被引：3，自引：0，他引：3
Although springs have been recognized as important, rare, and globally threatened ecosystems, there is as yet no consistent and comprehensive classification system or common lexicon for springs. In this paper, 12 spheres of discharge of springs are defined, sketched, displayed with photographs, and described relative to their hydrogeology of occurrence, and the microhabitats and ecosystems they support. A few of the spheres of discharge have been previously recognized and used by hydrogeologists for over 80 years, but others have only recently been defined geomorphologically. A comparison of these spheres of discharge to classification systems for wetlands, groundwater dependent ecosystems, karst hydrogeology, running waters, and other systems is provided. With a common lexicon for springs, hydrogeologists can provide more consistent guidance for springs ecosystem conservation, management, and restoration. As additional comprehensive inventories of the physical, biological, and cultural characteristics are conducted and analyzed, it will eventually be possible to associate spheres of discharge with discrete vegetation and aquatic invertebrate assemblages, and better understand the habitat requirements of rare or unique springs species. Given the elevated productivity and biodiversity of springs, and their highly threatened status, identification of geomorphic similarities among spring types is essential for conservation of these important ecosystems. 相似文献
15.
过去,人们对岩(矿)石磁参数测定工作不够重视,多数磁测工作是按照相应的工作规范只是测一测岩(矿)石磁参数.甚至有不少磁测工作不对工区内的岩(矿)石标本做磁参数测定工作,或只做少量的测定工作.而这些为数不多的磁参数测定工作也只是作磁化率和剩余磁化强度的平均数(众数)统计,没有对标本磁参数离散程度进行深入的统计研究.尽管利用变异系数表征磁参数的相对离散程度是很早就被人们认识到的.但是,目前就是在极少数关注磁参数离散程度的研究者中,也多引用标准离差,而不是变异系数.笔者对岩(矿)石标本磁参数的变异系数作了浅显的研究,并认为研究岩石磁性强度的自身不均匀性和相互之间的不均匀性对比,变异系数应当是一个不错的参数. 相似文献
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高凡金矿床是次火山热液型中低温金（银）矿床，对矿石中主要矿石矿物自然金、石英，黄铁矿，银矿物，闪锌矿，方铅矿和方解石等矿物标型性研究，得出了高凡金（银）矿床的矿物标型特征及空间分布规律，利用这些规律可指导该矿床深部的找矿工作及区域上同类型矿床的寻找。 相似文献
18.
震后沟道泥石流启动条件——松散堆积体雨中失稳的水力学机制分析 总被引：2，自引：0，他引：2
5.12地震导致大规模的松散崩滑物质堆积于沟道,极大的增加了震后降雨型沟道泥石流爆发的概率。然而,灾后特殊的物源条件和成灾环境改变了传统沟道泥石流的形成机制,给震后沟道泥石流的防治工作带来了巨大的困难。为此,以水文学为基础,在构建松散堆积体潜水位变化水文学模型的前提下,借助水力学理论,分析了沟道堆积体内水力随潜水位变化的规律和特征,研究作用在单元条块堆积体上静水压力和动水压力的计算方法。在合理分段沟道松散堆积体的前提下,基于无限边坡理论完成了对各段堆积体下滑力、基底抗滑力及剩余下滑力的表达构建。结合算例解析了震后降雨条件下堆积体失稳的力学机制。分析表明,震后沟道松散堆积体失稳启动并泥石流化是流域降雨作用下堆积体内潜水位不断抬升、水力环境不断劣化的结果。流域大、沟道窄、堆积深、导水系数小、沟床缓的堆积体因较高的潜水位更易在降雨中失稳,且失稳模式因条块间剩余下滑力差异而分为整体推移启动及解体牵引启动两类。 相似文献
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下扬子区三叠纪古地理演化 总被引：2，自引：2，他引：0
下扬子区在三叠纪期间接受了早-中三叠世海相碳酸盐沉积、中-晚三叠世海陆交互相和陆相湖沼沉积.沉积相带的空间分布和古地理格局的变迁明显地受到区域构造的控制.区内盆地发育与演化是在华南板块与扬子板块、扬子板块与华北板块相互作用的背景下进行的.早-中三叠世末期的印支运动是下扬子区构造-古地理格局改变的决定性因素,使下扬子海盆闭合,沉积类型由海相沉积变为陆相沉积.下扬子区三叠纪古地理的演化特征也为板块碰撞提供了沉积证据. 相似文献
20.
地形地貌是崩塌、滑坡、泥石流等地质灾害活动的基础,它在很大程度上决定了崩塌、滑坡、泥石流等地质灾害能否形成及其类型、数量、密度和规模大小。本文基于湘东南详细地质灾害调查成果,对该市不同地貌类型、坡形、坡度以及高程的差异对地质灾害发育规律的控制作用进行了总结分析。 相似文献