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本文从粤西罗定盆地及周边断裂构造控矿作用特征出发,分析矿床成矿作用。其断裂构造控矿作用主要体现在三个方面:其一,区域性深大断裂、大断裂、次级断裂分别控制了区内矿带、矿床、矿体;其二,构造演化过程控制着不同时期不同矿种的形成;其三,断裂构造通过对含矿岩体的控制,进而控制部分矿床的形成。 相似文献
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干旱气候条件下的桌子山地区岩溶形态主要为裂隙及溶隙,岩溶含水岩组主要为中奥陶统马家沟组,岩溶水主要受近南北向推覆构造的控制,断层破碎带及影响带为富水地段。根据控水构造将研究区内岩溶水划分为岗德尔山、桌子山南段、桌子山北段及千里山四个子系统。根据水动力场、水化学及同位素场特征分析了各子系统补径排条件,其主要受降雨补给,其次为沟谷第四系潜流补给、东部白垩系地下水及上覆碎屑岩裂隙水的补给。岩溶水主径流方向由东向西,通过山前地带,最终排入黄河。通过对动态长观资料的分析确定了本区岩溶水动态类型。采用补给量法计算了岩溶水的天然资源量为0.23×108m3/a,可开采资源量为4.02×104m3/d,并论证了其保证程度。 相似文献
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长江河口地区第四系沉积体系的发育很大程度上受到海面波动的控制,其中地下水化学场也不可避免地受此影响,从而具有独特的演化模式.本文根据研究区的水文地质条件,划分出3个含水系统:全新统、中上更新统和下更新统含水系统;利用Piper图解区分了更新统2个含水系统中的水化学类型;同时探讨了地下水形成后所发生的演化.研究发现,区内地下水化学演化主要通3三种作用进行:①后期补给淡水对咸水的稀释作用;②地下水中钙离子对含水层沉积物中吸咐钠离子的交换作用;③不同类型地下水通过越流等形式发生的混合作用.另外,本区地下水中的Ca2+和CO32-离子对方解石来说已达过饱和. 相似文献
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红山子铀矿床是我国北方比较典型的火山岩型铀矿床。区内成矿地质条件优越,构造活动强烈。构造与成矿关系密切,它既是区内各种地质体之间耦合关系的主导因素,也是矿(化)体赋存的主要部位。作为该区重要的构造类型之一,推覆构造是本区F1断裂以西最主要的控矿因素。目前,区内推覆构造的表现形式、精细构造组成、形成时代及其对矿化的控制或破坏作用研究甚少,且存在很大争议,因此,加强构造控矿特征及其构造活动形成产物(断裂构造岩和充填于断裂构造中的矿脉)的研究,对指导推覆构造区的找矿工作有着重大的意义。本文着重对推覆构造的形成过程以及控矿作用进行了推断和讨论。 相似文献
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四川盆地三叠系地下水可划分出碎屑岩孔隙裂隙和碳酸盐岩岩溶裂隙两大储集类型。按此处构造开启程度和埋深条件等的不同,下中三叠统地下水有沉积变质水和渗入淋滤水两种基本成因类型,水动力特征各异。沉积变质水处于深埋封闭条件,受地静压力驱动控制;渗入淋滤水分布于背斜露头区和浅部地区,受静水压力驱动控制。并由此控制了盆地三叠系盐类的保存条件。 相似文献
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Reconstruction of the geological history of orogenic events can be challenging where basins have limited and/or fragmentary preservation. Here, we apply understanding gained from modern analogues to the sedimentological analysis of the succession of Upper Silurian to Lower Devonian Lower Old Red Sandstone (LORS), northern Midland Valley, Scotland, in order to reconstruct the foreland to the Caledonian orogeny. A new depositional model is presented which differs significantly from current understanding. Using facies analysis, grain size distribution and palaeocurrent data a large distributive fluvial system is reconstructed. Three lithofacies and nine sublithofacies are identified, forming fluvial channel and floodplain facies associations. The system was derived from an emerging mountain range in the Caledonian foreland undergoing constant tectonic rejuvenation to produce 9 km of coarse‐grained sediment, exhibiting an overall decrease in thickness towards the west and a large‐scale downstream reduction in grain size. Conglomerate sublithofacies dominate proximal areas in the east where amalgamated fluvial channel facies association is abundant, with a downstream increase in the dominance of floodplain facies. Additionally, observed grain size cyclicity is attributed to a pulsatory tectonic influence. The LORS records the time‐period between the late phases of the Caledonian Orogeny and the onset of post‐orogenic collapse in the mid‐Devonian and the presented model allows improved understanding of the north‐Atlantic Caledonian foreland. 相似文献
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Summary. This paper presents those results from the 1974 Lithospheric Seismic Profile in Britain (LISPB) which relate to the compressional velocity structure of the crust and uppermost mantle beneath Northern Britain. A combination of interpretation techniques suitable for modelling laterally inhomogeneous media, including two-dimensional ray-tracing and time-term analysis, has resulted in a detailed seismic cross-section across the Caledonian orogenic belt. The main features of this section are a possible horizontal discontinuity in the Pre-Caledonian'basement, a change in the relationship between the lower crust and the uppermost mantle from north to south and a considerable thickening of the crust beneath the Caledonian fold belt. These results place considerable constraints upon tectonic models for the evolution of the Caledonides in particular in their implication of differing crustal structures north and south of the Southern Uplands and their indication of the primary significance of the Southern Uplands Fault. 相似文献
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辽东古元古代变质硼矿床是我国最重要的硼矿资源,然而由于该区物质组成多样,构造演化复杂的特点,导致对于硼矿的物质来源、构造环境及成矿过程的认识存在很大差异。目前多数学者认为辽东硼矿床经历了早期的盐湖硼酸盐沉积阶段及晚期构造热事件引起的变质作用阶段。当前的研究认为古元古代辽东地区处于活动大陆边缘,且发育大量的钙碱性岩浆活动,这与第三纪以来的大型硼酸盐沉积矿床形成的构造环境及岩浆活动相似。结合现代盐湖体系下的硼酸盐沉淀物理化学条件讨论辽东地区古元古代沉积硼酸盐特征,根据硼同位素组成探讨物质来源及构造环境,发现辽东地区的硼矿床存在钠硼解石、硬硼钙石两种硼酸盐的沉积,硼同位素组成显示其硼源应来源于俯冲板块下蛇纹石及海相沉积物的脱水作用释放的硼,这种硼随钙碱性岩浆活动及热液活动在局限海盆中蒸发形成含水硼酸盐。 相似文献
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WINFRIED K. DALLMANN 《Polar research》1989,7(2):139-145
The previous literature on the occurrence of Tertiary strata at Renardodden provides contradictory information about the primary versus tectonic boundary with the Precambrian basement. Tertiary sandstones and shales overlie unconformably the basement rocks, which have been resedimented as boulder conglomerates prior to Caledonian metamorphism and weathered prior to the deposition of the Tertiary strata. The boundary relations are complicated by a repeatedly active fault system that may form part of the Inner Hornsund Fault Zone. 相似文献
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Detailed study of two dry depressions in the Baikal rift system: the E–W Khoito Ghol-Tunka-Bistraya depression and the SW–NE Gusinoje–Ivolga depression, aims to provide a better understanding of tectonic control on the intershoulder relief evolution after the rift opened. Both depressions are grabens and both feature a suite of 10–20 km-wide basins alternating with more or less massive highs. Field and laboratory analysis shows that this pattern is of recent tectonic origin and that local breaking-up and subsidence followed the general sinking which originally formed the grabens. The subsidence belts seem to have gradually shifted north and northeastwards. Geomorphological analysis reveals that in both depressions the highs are remnants of a former pediment which was broken up. The young basins display numerous relevant hydrographic anomalies of the secondary channels and a general water-logging. They also suggest that the subsidence belts have gradually shifted north-and northeastwards. In the Gusinoje–Ivolga depression evidence was found of a Plio-Pleistocene river course, parallel to the Selenga river, which was later dismantled by the breaking-up. This depression, parallel to the Baikal rift and belonging to the Mesozoic system of grabens in the Caledonian fold belt, seems to have been included into the general system of rifts during the Pliocene tectonic phase. As for the main hydrographic axes, the Selenga river was set on a Palaeogene-age planation surface before the first tectonic phase and kept its original course. The Irkut river flowed in the Khoito Gol–Tunka–Bistraya depression after the first tectonic phase and was not affected by the later breaking-up. In contrast, the secondary drainage network is largely discordant. Despite their different geotectonic contexts, the two depressions show a similar development of relief pattern,which poses the question of the style of rift dynamics after the main Pliocene tectonic phase. 相似文献
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Crustal extension during and following continental collision is well documented in the Arctic Caledonian fold belt. However, models for the post-collisional extension of the Caledonides are mainly based on geoscientific data from Scandinavia. For a more complete understanding of the evolution of the Caledonides, knowledge of the crustal structure of East Greenland is vital. Seismic and gravity studies have revealed a pronounced Moho topography and a west-dipping lower crustal reflector beneath the fjord region of East Greenland. These deep crustal structures are related to Late Caledonian extensional structures at the surface. The observations can be satisfactorily explained by applying simple shear or eduction models proposed for upper crustal extension in Scandinavia to the complementing lower crustal structures in East Greenland. However, exhumation of the Caledonian Northeast Greenland eclogite province cannot be accomplished by these models. Instead, a synthesis of geoscientific data has shown marked differences in the crustal structure of East Greenland north and south of about 76°N, indicating a different crustal evolution of the northern and southern parts of the East Greenland Caledonides. 相似文献
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Zsfia Ruszkiczay-Rüdiger Lszl Fodor Erzsbet Horvth Tams Telbisz 《Geomorphology》2009,104(3-4):203-217
The Gödöllő Hills, a low-relief terrain within the Central Pannonian Basin in Hungary, is characterised by moderate tectonic deformation rates. Although typical tectonic landforms are not clearly recognisable in the study area, this paper succeeded in discriminating between tectonically controlled landforms and features shaped by fluvial erosion or deflation with no tectonic control.DEM-based morphometric parameters including elevation, slope and surface roughness, enabled the delineation of two NW–SE trending spearhead-shaped ridges separated by a wide rectilinear valley of the same strike. Although directional statistics suggested possible tectonic control of NW–SE striking landforms, precise morphometry completed with an analysis of subsurface structures rejected their tectonic preformation. Deflation plays a significant role in shaping the area, and the presence of two large-scale yardangs separated by a wind channel is proposed. In temperate-continental areas of Europe, no deflational landforms of such scale have been described so far, suggesting that Pleistocene wind power in periglacial areas was more significant than it was previously thought.Characteristic drainage patterns and longitudinal valley profiles enabled the recognition of areas probably affected by neotectonic deformation. A good agreement was observed between locations of Quaternary warping predicted by the morphometric study and subsurface structures revealed by the tectonic analysis. Zones of surface uplift and subsidence corresponded to anticlinal and synclinal hinges of fault-related folds. In low-relief and slowly-deforming areas, where exogenous forces may override tectonic deformation, only the integrated application of morphometric and subsurface-structural indications could assure correct interpretation of the origin of various landforms, while a morphometric study alone could have led to misinterpretation of some morphometric indices apparently suggesting tectonic preformation. On the other hand, the described morphological expression of subsurface structures could verify Quaternary age of the deformation. 相似文献
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A post-tectonic Caledonian granite in southern Ny Friesland has been fully mapped and the following new names are proposed: the Chydeniusbreen granitoid suite, consisting of the Raudberget granitoid body in the north; the Newtontoppen granitoid body in the middle; and the Ekkoknausane granitoid body in the south
The contact relationships, internal structures and distribution of various rock types infer an asymmetric lopolith or a harpolith-like body, a large sickle-shaped intrusion stretched in the direction of general tectonic transport, for the Newtontoppen granitoid body.
Seven rock types are described in the Newtontoppen granitoid and four emplacement stages are recognised. The major rock types seem to have an alkali-calcic to alkalic bulk rock chemistry and show a transition between I- and S-type granite derived from anatectic melting of various protoliths under relatively high temperature conditions. Possible later K2 0 introduction modified the earlier formed rock types.
A Rb-Sr whole rock age of 432 ± 10 Ma has been obtained by a seven point isochron with MSDW = 2.59 and an initial Sr isotope ratio = 0.715. This age is approximately 30 Ma older than the previously obtained K-Ar whole rock and Rb-Sr biotite ages, ca. 400 Ma, which represents the period of cooling. The high initial Sr isotope ratio supports the interpretation of an anatectic origin. 相似文献
The contact relationships, internal structures and distribution of various rock types infer an asymmetric lopolith or a harpolith-like body, a large sickle-shaped intrusion stretched in the direction of general tectonic transport, for the Newtontoppen granitoid body.
Seven rock types are described in the Newtontoppen granitoid and four emplacement stages are recognised. The major rock types seem to have an alkali-calcic to alkalic bulk rock chemistry and show a transition between I- and S-type granite derived from anatectic melting of various protoliths under relatively high temperature conditions. Possible later K
A Rb-Sr whole rock age of 432 ± 10 Ma has been obtained by a seven point isochron with MSDW = 2.59 and an initial Sr isotope ratio = 0.715. This age is approximately 30 Ma older than the previously obtained K-Ar whole rock and Rb-Sr biotite ages, ca. 400 Ma, which represents the period of cooling. The high initial Sr isotope ratio supports the interpretation of an anatectic origin. 相似文献
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渭河盆地的地质构造与构造地貌类型 总被引：4，自引：1，他引：3
渭河盆地位于祁吕系、秦岭纬向构造体系,华夏系、陇西旋卷构造四大构造体系交汇地带,这种地质构造背景是形成盆地构造地貌的基础。按照构造-成因分类原则,对本区构造地貌划分为两级8个类型,又按新构造运动特点划分出相应的亚类。这些地貌类型分布具有东西延伸成带,南北对应,垂向成层具阶梯状的空间配置特点。渭河盆地在四大构造体系制约下,共地堑构造是决定地貌空间配置的主要原因。 相似文献
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通过对北极地区不同盆地结构的系统研究与对比分析,绘制了环北极沉积盆地群长剖面,剖面全长约13 000 km,涉及季曼-伯朝拉盆地等15个盆地和微陆。由于整个剖面尺度巨大,在若干缺乏详细资料的地区采用将邻近地区的其他剖面平移到本剖面中,或由其两侧的剖面地层和构造形式推测。剖面涉及的盆地多属叠合性质,涵盖克拉通盆地、裂谷盆地、前陆盆地、被动大陆边缘盆地等多种盆地类型;各区域沉积厚度差异显著,最厚的东巴伦支海等盆地沉积了自古生界至新生界的地层,沉积厚度可达近15 km ,而沉积最薄处的拉普捷夫海等盆地则只发育了从中生界上白垩统至新生界的沉积,厚度不超过4 km。以北大西洋—北冰洋洋中脊为界,北极地区分属欧亚板块和北美板块,很多盆地为大陆的一部分或大陆向北冰洋的延伸部分（大陆架）。各盆地的发育主要受波罗的板块、西伯利亚板块与劳伦古陆显生宙以来的构造演化控制;加里东运动、埃尔斯米尔运动、海西运动（乌拉尔运动）及大西洋洋脊自南向北的扩张对环北极盆地均有显著影响,具体表现为造成盆地类型的改变、改变盆地沉降速率等。 相似文献