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《吉林大学学报(地球科学版)》2015,(Z1)
<正>1地质背景373矿床位于华南板块南华活动带(Ⅱ)右江褶皱系(II2)西大明山凸起(II25),大新凹断束,那岭—俸屯褶断地垒的北端。矿区出露地层主要为寒武系、下泥盆统、中泥盆统,地层走向近东西,倾向近北。矿区内最大的断裂构造为俸屯褶断地垒北翼边缘的F2断裂带,该断层在矿区内走向近东西,倾向北。F2断层上盘产生了一系列派生的似层间分支断裂F1 3、F2 3、F3 3,矿体主要赋存于F3断层中。 相似文献
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贵州赫章猪拱塘铅锌矿床是贵州省内发现的首个中低温热液型超大型铅锌矿床。铅锌矿体严格受北西向断裂构造控制,主要赋存于北西向F1、F2及隐伏F20、F30断裂破碎带及次级断裂破碎带内。根据矿体的空间展布特点,以控容矿断裂作为矿体对比连接的依据,圈定69个铅锌矿体,探明铅锌金属资源量275万吨。Ⅰ-1号主矿体为区内规模最大铅锌矿体,呈似层状、透镜状产出于猪拱塘断层(F1)破碎带内,赋矿围岩建造为二叠系中统栖霞组(P2q)泥灰岩、灰岩、白云质灰岩建造。矿体长度1 640 m,平均厚11. 01 m,铅平均2. 81%,锌平均8. 71%。铅锌资源量182万吨,占矿床总资源量的57%,资源量规模达特大型。通过对Ⅰ-1号主矿体地质特征及找矿标志详细论述,为矿床总体特征及成矿规律总结提供依据。 相似文献
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铜陵马山金硫矿床位于沿江拱断褶带之贵池—繁昌断褶束的东段,铜官山背斜北东倾伏端东翼,矿体呈似层状、透镜状,受地层、构造、岩浆岩控制,尤其是层间断裂,倾伏端北东向纵断裂与脉岩交汇部位出现厚、富金矿体,深部找矿也取得重大成果,对长江中下游地区的找矿具有重大参考意义。 相似文献
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雄村铜(金)矿区位于西藏冈底斯成矿带中段南缘,由Ⅰ、Ⅱ、Ⅲ号矿体和多个矿化体组成。本文以Ⅰ、Ⅱ号矿体钾硅酸盐化蚀变带内的热液黑云母为研究对象,采用光薄片镜下鉴定、电子探针等分析方法,系统研究了热液黑云母的产状和成分特征。结果显示,雄村矿区Ⅰ号矿体黑云母类型主要为金云母和镁质黑云母;Ⅱ号矿体黑云母类型为镁质黑云母。两个矿体黑云母都具有低Ti(TiO_2 3%)、高Al(Al_2O_315%)的特点,且具有较高的MgO含量,Mg/Fe0.5,K/Na10,显示了与矿化良好的相关性。Ⅰ号矿体热液黑云母平均结晶温度470℃,氧逸度位于镍-氧化镍缓冲剂与磁铁矿-钛铁矿缓冲剂之间(NNO—HM);Ⅱ号矿体热液黑云母平均结晶温度234℃,氧逸度位于镍-氧化镍缓冲剂与铁橄榄石-石英-磁铁矿缓冲剂之间(NNO—FQM),说明Ⅰ号矿体形成于较高温、高氧逸度的热液系统,Ⅱ号矿体形成于相对较低温、低氧逸度的热液系统。此外,Ⅰ号矿体热液黑云母Ⅳ(F)值介于0.61~2.72之间,平均值1.26,Ⅳ(Cl)值介于-5.49~-4.53之间,平均值-5.03,Ⅳ(F/Cl)值介于5.63~7.89之间,平均值6.29;Ⅱ号矿体热液黑云母Ⅳ(F)值介于1.83~3.32之间,平均值2.66,Ⅳ(Cl)值介于-5.64~-4.89之间,平均值-5.31,Ⅳ(F/Cl)值介于7.14~8.68之间,平均值7.97,说明Ⅰ、Ⅱ号矿体都形成于富Cl的热液系统,且Ⅱ号矿体热液较Ⅰ号矿体更富Cl,贫F。富Cl流体易萃取流体中的Cu和Au等金属元素并以Cl的络合物形式运移,在沿构造裂隙向上运移的过程中,物理化学条件发生改变,使得流体中金属元素络合物溶解度降低,促使硫化物沉淀成矿。 相似文献
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研究区处于江南地轴北缘一凹断褶束部位。加里东-印支旋回的沉积组成了近乎平行的呈东西向展布的若干褶皱;第三系为内陆断陷盆地的沉积,受东西向和北北东向两组断裂控制(图1)。 相似文献
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江永庵堂岭铅锌银矿床外接触带主矿体属岩溶型矿体,本文预测已知Ⅱ、Ⅲ号岩溶矿体的两侧赋存有Ⅰ、Ⅳ、Ⅴ号岩溶矿体,每组岩溶由上、下两个岩厅及廓道组成,岩溶组之间的间距约120~150m。根据早期充填岩溶的方解石晕并结合其它构造标志,能够有效地在坑下预测隐伏岩溶。地质预测结论与特探激电异常结果吻合。 相似文献
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A recently discovered articulated partial skeleton of Ornithomimus from the Upper Cretaceous Dinosaur Park Formation of Alberta, Canada is remarkable in the extent and quality of preservation of integumentary structures including feathers. It is the first ornithomimid to preserve a tail bearing extensive plumaceous feathers that are slightly more elongate in comparison to those present on the remainder of the body. However, the underside of the tail and the hind limb distal to the middle of the femur appear devoid of plumage. Overall, the plumage pattern in Ornithomimus is similar to that of Struthio camelus (ostrich) and other large palaeognaths, indicating a probable function in thermoregulation. The specimen also preserves the body outline around the legs, including a skin contour anterior to the femur, analogous to skin webs in extant birds. Whereas the knee web of birds bridges the knee to the abdomen, in Ornithomimus it spans from the mid-femoral shaft to the abdomen, and is herein referred to as an anterior femoral web. This is the first report of such soft tissue structures in non-avian theropods. It may indicate that the resting position of the femur was positioned more anteroventrally in ornithomimids than in most theropods, and in that sense may have been transitional to the situation in modern birds. 相似文献
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The new tribe Mediumiugamiini (Coleoptera: Polyphaga: Tenebrionoidea: Mordellidae) is described based on Mediumiuga sinespinis gen. et sp. nov. It is a fossil beetle from Albian (Early Cretaceous) amber from the Peñacerrada I outcrop (Spain). It is the first Spanish beetle described in amber. The mesotibiae and mesotarsi bearing multiple dorsal–lateral ridges, running oblique, metatibiae without any dorsal or dorsal–lateral ridge, only showing a subapical ridge, and metatibiae without apical spurs, define the new tribe. A key for worldwide tribes of Mordellinae, including Mediumiugamiini, is provided. Evolution of some characters of Mordellidae along Cretaceous is discussed. 相似文献
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Tyrannosaurs and hadrosaurs from the Late Cretaceous of eastern North America (Appalachia) are distinct from those found in western North America (Laramidia), suggesting that eastern North America was isolated during the Late Cretaceous. However, the Late Cretaceous fauna of Appalachia remains poorly known. Here, a partial maxilla from the Campanian Tar Heel Formation (Black Creek Group) of North Carolina is shown to represent the first ceratopsian from the Late Cretaceous of eastern North America. The specimen has short alveolar slots, a ventrally projected toothrow, a long dentigerous process overlapped by the ectopterygoid, and a toothrow that curves laterally, a combination of characters unique to the Leptoceratopsidae. The maxilla has a uniquely long, slender and downcurved posterior dentigerous process, suggesting a specialized feeding strategy. The presence of a highly specialized ceratopsian in eastern North America supports the hypothesis that Appalachia underwent an extended period of isolation during the Late Cretaceous, leading the evolution of a distinct dinosaur fauna dominated by basal tyrannosauroids, basal hadrosaurs, ornithimimosaurs, nodosaurs, and leptoceratopsids. Appalachian vertebrate communities are most similar to those of Laramidia. However some taxa-including leptoceratopsids-are also shared with western Europe, raising the possibility of a Late Cretaceous dispersal route connecting Appalachia and Europe. 相似文献
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Here we describe an isolated tooth of a metriorhynchid crocodylomorph from the Hybla Formation (Aptian, Lower Cretaceous) of Rocca Chi Parra quarry (Montagna Grande, Calatafimi, Trapani Province), Sicily, Italy. The specimen shares with the Upper Jurassic taxon Plesiosuchus manselii a mediolaterally compressed conical tooth crown, noticeable lingual curvature, mesial and distal carinae with microscopic, rectangular contiguous denticles, strong distal curvature of the mesial margin, and the presence of weak 'carinal flanges' on the labial and lingual surfaces (which are preeminent at the mid-crown). This suite of morphologies is also present in an unnamed Valanginian (Lower Cretaceous) plesiosuchinan from France. However, the Sicilian tooth differs from these taxa in having more pronounced carinae, and faint apicobasally aligned enamel ridges. It also differs from P. manselii in having more extensive 'carinal flanges' on the labial surface. The specimen extends the known geological range of Metriorhynchidae and Thalattosuchia by approximately 7–8 million years. This overturns previous hypotheses of Metriorhynchidae becoming extinct early in the Early Cretaceous. 相似文献
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闽东南长乐-南澳断裂带“片麻状”浆混杂岩的厘定及其地质意义 总被引:9,自引:1,他引:8
近年来的区域地质调查在闽东南长乐-南澳断裂带中,多处新发现白垩纪(辉长)闪长质和二长花岗质岩浆经机械的、化学的混合形成各种浆混岩类,与两混合端元岩石共同构成浆混杂岩,成岩后还受到应力作用。它们因特殊的结构构造而长期被归入混合花岗岩或片麻状花岗岩类。描述了泉州市肖厝、福清市高山等地浆混杂岩的野外地质特征,并与莆田市和福清市的典型变质变形花岗岩类进行了对比,指出这3类岩石之间有明显的区别,浆混杂岩可能形成于主变质变形期之前早白垩世早期的伸展环境中。 相似文献
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Selenium fractionation and speciation in rocks, soils, waters and plants in polluted surface mine environment 总被引:1,自引:0,他引:1
A fractionation and speciation was performed to determine the distribution of selenium (Se) species in major components of quartzite surface mine environment (rocks, mine tailings, soils, stream sediments, surface waters and plants) in obov, Slovakia. A three-step sequential extraction procedure was utilised for the fractionation of Se in mine tailings and soils. The first extractant in order to evaluate the soluble and ligand exchangeable fraction of Se (0.1 mol/l K2HPO4 + KH2PO4 at pH 7.0) solubilized up to 15% of total Se content. The second step (0.1 mol/l K2S2O8 at 90°C) which extracted Se associated or occluded with organic matter released 13 – 45% of total selenium. The decomposition of the residue (HNO3 + H2SO4 1+1) was used to solubilize the remaining 35–88% of total Se as the final step. The recovery of the procedure was between 97 and 106%. Selenate predominated in natural river and lake waters about pH 7.0 (>95%) but in acid mine leakings up to 40% of selenite was found. In the plants (birch leaves, grass leaves and roots) collected from the area acidified by mine leakings no significant accumulation of selenium was observed. The correlation between total Se and S in the rocks from the mine gives an evidence of the common origin of these elements in the studied area. 相似文献
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高级变质岩中Zr、Hf、Nb、Ta的ICP-MS准确分析 总被引:15,自引:0,他引:15
采用高压密闭溶样ICP-MS研究了片麻岩、榴辉岩等高级变质岩中Nb、Ta、Zr、Hf准确分析方法。实验表明:在温度为190℃时,溶样时间大于36h,Nb、Ta、Zr、Hf可完全溶解,而获得准确的分析结果。但Nb、Ta在稀硝酸介质中的不稳定性会导致分析结果的误差,采用0.1%HF介质的“F^-基体”匹配,可保持Nb、Ta长时间的稳定性。所建立的高压密闭溶样ICP-MS分析方法用于苏鲁-大别地区片麻岩、榴辉岩等高级变质岩的分析,经与XRF及碱熔融ICP-MS方法对比,分析结果具有良好的一致性。 相似文献
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新疆北山大地构造属性及演化特征 总被引:8,自引:1,他引:7
本文首次提出新疆北山古生代大地构造属性为板内断裂造山带,具有下列基本特征:①造山带形成和发展受主断裂控制;②以成熟度低、分选差的陆源碎屑沉积为主;③岩浆活动有其本身的特点;④横向不均一性特征非常突出;⑤剖面结构构造特征,主要从造山带两侧分别向外缘逆冲,构成背冲型;⑥空间上由三个断裂造山带平行排列组合在一起;⑦时间上经历了三个断裂造山旋回。 相似文献