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1.
青海省民和县中川乡美一和美二村地下水位上升原因分析 总被引：1，自引：0，他引：1
民和县中川乡美一和美二村因为地下水位上升引发了一系列不良反应。根据研究区的地质环境条件,分区计算地下水补给量与排泄量,定量讨论地下水上升原因,结合研究区水位地质条件和工程环境定性讨论地下水位上升原因。综合分析认为,区内地下水位上升主要原因是修建防渗堤坝使堤内地下水排泄不畅,导致地下水位上升。 相似文献
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张掖盆地地下水位上升成因探析 总被引：4，自引：0，他引：4
张掖盆地80年代中期以来,地下水位处于区域性持续下降过程。2001年9月以来,盆地中北部地下水位停止下降开始出现上升趋势,特别是2005年9月以来,张掖盆地地下水位突然大面积上升。分析认为,地下水位上升主要是补给量的增加所致,主要增加途径有两个：一是本世纪以来,受全球气候转暖的影响,祁连山中西部的冰川融水和降水量明显增加,使祁连山区各河流出山径流量亦相应的增加,而出山河流作为盆地内地下水的主要补给来源,它的增加则意味着盆地地下水补给量的增大;二是黑河河床过水时间增加,在流经盆地第四系粗颗粒相强导水的洪积扇地带,大量“线状”入渗,使地下水补给量增大,引发沿河地下水位上升,导致向黑河排泄的黑河以东地下水径流受阻。 相似文献
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降水量与地下水补给量的关系分析 总被引：11，自引：0，他引：11
降水入渗补给是地下水的主要补给源，研究降水与地下水的关系，主要是分析由于降水垂直入渗引起的地下水位的变化。本文主要通过对降水入渗机理、影响水入渗的因素、降水入渗补给量计算的研究，分析降水量与地下水补给量的关系。 相似文献
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以地下水污染调查数据、地下水监测数据和遥感数据为基础，分析了1998年以来（1998—2019年）兰州不同区域地下水环境变化趋势，探讨了土地利用变化、污染源排放、地下水开采等城市发展要素对地下水的影响。结果表明：1998年以来兰州市地下水环境变化的主要特征是水质恶化、水位上升。溶解性总固体、总硬度、硝酸根、氟等典型水化学指标在大部分地区呈稳定上升趋势，局部地下水中硝酸根比重增加，出现了硝酸型地下水。污染负荷增加是水质恶化的重要驱动因素，且恶化指标与城市主体功能存在直接关系，城关区是主要的居住、商业区，水质恶化的典型指标为硝酸盐；西固区是化工、冶炼等重工业集中区，地下水污染程度最重，反映工业污染的氟化物上升显著；七里河区、安宁区是商业、居住及轻工业的综合分布区，矿化度、总硬度、硝酸根等指标都有不同程度上升，但升幅不大。西固及三滩地区地下水位上升较为明显，其他城区相对稳定，城市不透水界面阻碍了降雨、灌溉等地表垂直入渗，使地下水位年内波动趋于平缓；水源地开采量减少、沿河工程建设以及地下管网渗漏等因素导致地下水补径排条件发生变化，不仅引起城区地下水位上升，还能够增强污染物淋滤和地下水蒸发浓缩，对水化学环境造成一定影响。 相似文献
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层状土壤上升毛管水运移特性试验研究 总被引：3，自引：0，他引：3
通过室内土柱模拟试验,进行了层状土与均质土的对比试验,对层状土壤毛管水运动特性进行了研究,分析了层状土壤毛管水上升高度、速率及地下水补给量与时间的关系,并研究了毛管水上升高度与地下水补给量之间的关系。结果表明,砂层对毛管水上升的高度、速率以及地下水补给量有明显影响,砂层对于水分有着明显的阻滞作用。 相似文献
9.
青海省格尔木山前平原区地下水动态特征分析 总被引：4，自引：1，他引：3
在格尔木山前平原区水文地质条件基础上,结合多年地下水位监测资料,对格尔木河冲洪积平原区的多年水位动态特征及其影响因素进行了分析研究,总结出该地区的地下水动态类型.格尔木山前平原区3个不同区域由于赋存条件及开发利用条件的不同,地下水动态类型分异显著.研究区地下水整体流向与地形起伏相一致,自南向北径流,区域上流场形态变化不大.冲洪积扇中上部地下水多年动态处于平衡状态,近年来由于开采力度加大,地下水位呈急速下降趋势,地下水动态类型为水文-径流型;冲洪积扇下部地下水位以区域性下降为主,地下水动态类型主要为蒸发型;冲洪积扇西翼水源地附近由于地下水调蓄能力较强,地下水位总体呈稳定并局部有上升趋势,地下水动态类型为水文-人类活动型. 相似文献
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根据邯郸县水文地质条件,建立水文地质概念模型和地下水流数学模型,采用可视化标准软件Visu-al Modflow对研究区地下水进行数值模拟计算及预测。通过自动与手动相结合的方式,多次对模型进行调整,实现模拟计算结果与实际观测值的较好拟合;并以调节均衡型开采动态为原则,制定了2015、2020年县域浅层地下水设计开采量方案。模拟结果表明,2011年至2015年地下水位有明显下降趋势,地下水位下降3 m,2015年以后,在限采条件下,控制开采量,地下水位平均降深稳定在3.5 m左右,流场趋于稳定。 相似文献
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The NNW-trending tectonic grain of the eastern Yilgarn Craton (EYC) was established as a result of predominantly ENE–WSW directed extension (D1 and D3) and E(ENE)–W(WSW) (D2, D4) to NE–SW directed (D5) contraction. The result has been a succession of NNW-striking temporally discrete fabric elements, which can be difficult to interpret reliably at any single location. Despite this, many past workers interpreted the NNW-striking fabric as the result of only one regional contractional event, and used it as a marker for correlating structural events across the region. In order to unravel the complexity, this paper presents a new sixfold (D1–D6) deformation nomenclature based on >10,000 new mesoscale structural observations, including their kinematic analysis and cross-cutting relationships. These mesoscale data were referenced with regional 3D map patterns, stratigraphic-magmatic-metallogenic considerations, and deep seismic reflection images. This integrated geodynamic-architectural approach is applicable to solving structural-event histories in other polydeformed terrains. Gold mineralisation occurred during the first five events, but was particularly concentrated from D3 onwards. The D3 event marked the most profound change in the tectonic evolution of the EYC, with changes in greenstones, granites and tectonic mode (lithospheric extension and core complexes), with the first significant gold deposited within extensional shear zones that dissect the crust. Later contraction (D4) was imposed at a high angle to the previously established anisotropic architecture. The outcome was the creation of a new dynamic permeability framework, which resulted in gold mineralisation during NNW-striking sinistral strike-slip faulting and associated thrusting. A further stress switch (D5) further modified the architecture resulting in N- to NNE-striking dextral strike-slip faulting, and the final period of gold mineralisation, before late-stage extension (D6). 相似文献
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新疆蒙库铁矿床稀土元素地球化学及对铁成矿作用的指示 总被引：16，自引：4，他引：16
新疆富蕴县蒙库大型铁矿呈层状、似层状、透镜状赋存于下泥盆统康布铁堡组变质火山-沉积岩系中.矿体中发育矽卡岩,但矽卡岩并不产在侵入岩接触带上.绿帘石、石榴石和矿石的稀土配分模式具有相似性,均为轻稀土富集,正铕异常,基本上无铈异常,暗示它们之间存在成因联系.石榴石稀土配分模式呈折线型,具有明显的正铕异常,石榴石流体包裹体中熔融包裹体、熔流包裹体和气液包裹体共存,表明石榴石矽卡岩具有岩浆成因和热液成因的特征,形成于晶体 熔体 流体三相共存的岩浆-热液过渡阶段.矿床地质特征、矽卡岩矿物和矿石稀土特征表明蒙库铁矿为矽卡岩型矿床. 相似文献
13.
冷水江市浪石滩滑坡及其防治措施探讨 总被引：1，自引：0，他引：1
浪石滩大型滑坡的形成,除具有自然边界条件、地质结构面和斜坡地貌形态外,还有地下溶洞的带状发育,也是重要原因之一。而井下采煤造成的顶板岩层位移变形,则是诱发滑坡的主要原因。由于地下采煤与滑坡密切的成生联系,预测发展下去,滑坡造成的灾情惨重。因此,做好治理前的地质勘查与采煤时的地表变形防治极为重要。 相似文献
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东天山红山Cu-Au矿床氧化带首次发现的副针绿矾巨晶及其多型针绿矾 总被引：4，自引：1，他引：3
一种艳丽的蓝紫色矿物巨晶在我国新疆哈密地区红山铜.金矿床氧化带中、上部大量出现,经详实的野外地质观察和室内测试,如X-射线单晶及粉晶衍射测定、湿法化学分析、热分析、穆斯堡尔谱和红外光谱测试等,确认其为一罕见硫酸盐矿物-副针绿矾(Paracoquimbite,Fe2(So4)3·9H2O),是继智利丘基卡马塔巨型宽岩铜矿区1935年报道后,在世界上的又一次发现,在我国尚属首次.该矿物晶体如此之硕大(单晶粒度可达8cm～12cm),远大于智利首次发现的晶体(1.95cm),在国内外和自然界亦堪称首例,与副针绿矾密切共生者为针绿矾,二者呈多型关系.本文副针绿矾湿法化学分析结果为(wt%):SO3 42.55,Fe2O3 28.19,H8O 28.72,CaO 0.02,MgO 0.01,AL2O3 0.03,Na2O 0.02,总计99.54,其XRD特征谱线为:4.61(100),8.89(83),3.38(67);针绿矾湿法化学分析结果为(wt%):SO,3 42.31,Fe2O3 28.61,H2O 28.98,MgO 0.01,Al2O30.01,总计99.92,其XRD特征谱线为:8.27(100),5.46(76),2.77(76).红外光谱分析判定了不同基团及同一种基团在不同结构环境下振动模式或频率的差别.穆斯堡尔谱分析确定了副针绿矾和针绿矾中铁的氧化态、配位数以及结构中存在共价键(霄键).其穆斯堡尔谱共有特征是四极矩分裂值较小,均由单一吸收峰组成.各种实验分析数据完全吻合,保证了副针绿矾和针绿矾研究的准确性和可靠性.在同一标本上连续切片,通过连续系统的电子探针分析,对针绿矾与副针绿矾互为多型的成因机理做了初步探讨.红山矿区氧化带中除与该矿物副针绿矾共生者外,尚有其它多种硫酸盐矿物亦为我国首次发现.目前上述诸多矿物已作为湿法冶铜及制酸工业的新型资源,副针绿矾巨大晶体的发现兼有一定的实用价值和收藏价值. 相似文献
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3-D seismic structure of the Kachchh,Gujarat, and its implications for the earthquake hazard mitigation 总被引：3，自引：2，他引：1
Several pieces of studies on the January 26, 2001, Bhuj earthquake (Mw 7.6) revealed that the mainshock was triggered on the
hidden unmapped fault in the western part of Indian stable continental region that caused a huge loss in the entire Kachchh
rift basin of Gujarat, India. Occurrences of infrequent earthquakes of Mw 7.6 due to existence of hidden and unmapped faults
on the surface have become one of the key issues for geoscientific research, which need to be addressed for evolving plausible
earthquake hazard mitigation model. In this study, we have carried out a detailed autopsy of the 2001 Bhuj earthquake source
zone by applying three-dimensional (3-D) local earthquake tomography (LET) method to a completely new data set consisting
of 576 local earthquakes recorded between November 2006 and April 2009 by a seismic network consisting of 22 numbers of three-component
broadband digital seismograph stations. In the present study, a total of 7560 arrival times of P-wave (3820) and S-wave (3740)
recorded at least 4 seismograph stations were inverted to assimilate 3-D P-wave velocity (Vp), S-wave velocity (Vs), and Poisson’s
ratio (σ) structures beneath the 2001 Bhuj earthquake source zone for reliable interpretation of the imaged anomalies and
its bearing on earthquake hazard of the region. The source zone is located near the triple junction formed by juxtapositions
of three Indian, Arabian, and Iranian tectonic plates that might have facilitated the process of brittle failure at a depth
of 25 km beneath the KRB, Gujarat, which caused a gigantic loss to both property and persons of the region. There may be several
hidden seismogenic faults around the epicentral zone of the 2001 Bhuj earthquake in the area, which are detectable using 3-D
tomography to minimize earthquake hazard for a region. We infer that the use of detailed 3-D seismic tomography may offer
potential information on hidden and unmapped faults beneath the plate interior to unravel the genesis of such big damaging
earthquakes. This study may help in evolving a comprehensive earthquake risk mitigation model for regions of analogous geotectonic
settings, elsewhere in the world. 相似文献
16.
The geological structure of the island of Ios, Cyclades, Greece, is a dome consisting of an augengneiss core and a mantle of garnet-mica schists that together form the Basement which is overthrust by a marble-schist Series. This Series is mainly made up of meta-volcanics and metamorphosed sediments, presumably Mesozoic in age. It is a tectonically composed pile of marbles alternating with glaucophane schists, actinolite schists and chlorite schists. Petrological relations and isotope dating indicate the polymetamorphic character of Ios. Two Alpine metamorphic phases, M1 and M2, and relicts of a high grade metamorphic or magmatic phase (Mo), that only affected the Basement, are demonstrated. Radiometric ages obtained for the Basement confirm the interpretation that the Mo phase is Pre-Alpine. The M1 and M2 were dated at 43 Ma and 25 Ma respectively. The P-T conditions of metamorphism are estimated as 9–11 kb and 350 to 400° C for the M1 phase and 5–7 kb and 380–420° C for the M2 phase. The metamorphic history of the Cyclades is discussed and it is suggested that Pre-Alpine Basement occurs also on Sikinos and Naxos.
Zusammenfassung Die Kykladeninsel Ios besteht zur Hauptsache aus einem Gneisdom. Der Kern dieses Doms ist ein Augengneiskomplex, welcher von Granat-Muskovit-Schiefern umhüllt wird. Auf dieses Grundgebirge ist eine Marmor-Schiefer-Serie überschoben worden, eine tektonisch bedingte Wechselfolge von Metasedimenten und Metavulkaniten, wahrscheinlich mesozoischen Alters.Die petrologischen Gegebenheiten und Isotopendatierungen bezeugen Polymetamorphose. Es konnten zwei metamorphe Phasen alpidischen Alters nachgewiesen werden, M1 und M2, sowie die Spuren einer hochgradigen, metamorphen oder magmatischen Phase Mo, welche nur die Basis betroffen hat.Radiometrische Alterbestimmungen bestätigen die Deutung, daß das Grundgebirge voralpidisches Alter hat. Die Phasen M1 und M2 wurden datiert auf 43 Mj. und 25 Mj. Die Druck-Temperatur-Bedingungen der M1 und M2 wurden abgeschätzt auf 9–11 Kb und 350–400° C für die M1 und auf 5–7 Kb und 380–420° C im Falle der M2. Der metamorphe Werdegang der Kykladen wird diskutiert sowie die mutmaßliche Existenz eines vergleichbaren voralpidischen Grundgebirges auf den Nachbarinseln Sikinos und Naxos.
Résumé La structure géologique de l'île d'Ios (Cyclades, Grèce) est un dôme. Le noyau du dôme est un complexe d'augengneiss enveloppé par des schistes à grenat et mica. Ce noyau, qui constitue le socle, est chevauché par une série composée d'une succession tectonique de marbres et de schistes à glaucophane, de schistes à actinote et de schistes à chlorite. Les relations pétrologiques et les datations isotopiques indiquent le caractère polymétamorphique de l'île d'Ios. On y peut démontrer deux phases de métamorphisme alpin (M 1 et M 2) ainsi que des témoins d'une phase métamorphique ou magmatique antérieure qui n'a influencé que le socle. Les datations radiométriques obtenues pour le socle confirment l'âge préalpin de la phase M 0. Les phases M 1 et M 2 sont datées à 43 et 25 Ma respectivement. Les conditions du métamorphisme des phases M 1 et M 2 sont estimées respectivement à 9–11 kb avec 350–400° C, et 5–7 kb avec 380–420° C. L'histoire métamorphique des Cyclades est discutée ainsi que la présence probable d'un socle Préalpin comparable dans les îles voisines de Sikinos et de Naxos.
Kykladen los . — , , . , , - , , . (M1 M2) , ( m0), . , . M1 M2 - 43, 25 . M1 9–11 350–400° , 2 5–7 380–420° . . Kykladen - Sikinos Naxos.相似文献
17.
准噶尔盆地西北缘三叠系重矿物特征及其物源指示意义 总被引：2，自引：0，他引：2
重矿物是物源变化极为敏感的指示剂。本次研究运用重矿物组合、重矿物百分含量统计分布、SPSS统计—因子分析及相关分析方法对准噶尔盆地西北缘三叠系地层中采集的20件砂岩、砂砾岩样品进行研究。通过重矿物特征及指示参数分析得到4类重矿物组合:锆石—电气石—锐钛矿—独居石—磷灰石组合,金红石—钛铁矿—白钛石—辉石组合,方铅矿—赤褐铁矿—黄铁矿组合以及磁铁矿—绿帘石—角闪石组合,推测母岩组合为中—酸性岩浆岩+沉积岩+变质岩;认为这套碎屑岩的源区为西北—北部的齐尔山—哈拉阿拉特山一带(属扎伊尔山前),物源为下石炭统太勒古拉组肉红色花岗岩,灰色—灰绿色安山岩、安山玢岩及灰色—灰黑色凝灰岩、粉—细砂岩,并且成岩显示为近源物质和远源物质混杂堆积。 相似文献
18.
Rare Earth Element Evidence for the Petrogenesis of the Banded Series of the Stillwater Complex, Montana, and its Anorthosites 总被引：1，自引：0，他引：1
LOFERSKI PATRICIA J.; ARCULUS RICHARD J.; CZAMANSKE GERALD K. 《Journal of Petrology》1994,35(6):1623-1649
A rare earth element (REE) study was made by isotope-dilutionmass spectrometry of plagioclase separates from a variety ofcumulates stratigraphically spanning the Banded series of theStillwater Complex, Montana. Evaluation of parent liquid REEpatterns, calculated on the basis of published plagioclase-liquidpartition coefficients, shows that the range of REE ratios istoo large to be attributable to fractionation of a single magmatype. At least two different parental melts were present throughoutthe Banded series. This finding supports hypotheses of previousworkers that the Stillwater Complex formed from two differentparent magma types, designated the anorthositic- or A-type liquidand the ultramafic- or U-type liquid. On the basis of our data,one melt has a REE pattern with a distinctive shallow slopeand is represented by samples from the thick, massive Anorthositezones I and II (AN I and AN II) of the Middle Banded series.Although samples from AN I and AN II are separated by as muchas 1400 m stratigraphically, they have remarkably similar calculatedparent liquid characteristics, with (Ce/Sm)n = 1.7–1.9,(Nd/Sm)n = 1.3–1.4 and (Ce/Yb)n = 2.9–4.6 (wheren denotes chondrite-normalized). These calculated liquids areprobably close to representing A-type magma. In addition, plagioclase-bronzitecumulates from Norite zones I and II (N I and N II), althoughthought to be U-type cumulates, contain plagioclase that hasA-type REE characteristics, implying that A-type magmas wereinjected into the magma chamber during formation of those zones.In contrast, calculated parent liquids of cumulus augite-bearingrocks have REE patterns that display distinctly steeper slopesthan the A-type REE pattern. The extreme is the calculated parentliquid of a plagioclase-bronzite-augite cumulated with (Ce/Sm)n= 2.9, (Nd/Sm)n = 1.7, and (Ce/Yb)n = 10.1. Analysis of published REE and Nd isotopic data for Stillwatercumulates reveals similarities between AN I, AN II, and otherthin plagioclase cumulate layers in the Lower and Upper Bandedseries, which supports the notion that they were all derivedfrom similar (A-type) parent melts. In contrast, plagioclaseseparates from cumulus augite-bearing rocks display light REEand Nd isotopic characteristics that are similar to U-type cumulatesfrom the Ultramafic series as described by previous studies.Thus far, the only cumulates from the Banded series that displayU-type REE and Nd isotopic characteristics are those that containcumulus augite. Therefore, cumulus augite appears to be an importantindicator of magmatic parentage. The REE and Nd isotopic ratios show erratic variation with stratigraphicposition, indicating that the magmas from which the Banded seriescrystallized were injected at various levels into the magmachamber. Different cumulate types crystallized from discreteliquids, as indicated by the correlation between REE signatureand cumulate type. Samples from Olivine-bearing zones III andIV (stratigraphically between AN I and AN II) display a rangein REE ratios; e.g., (Ce/Sm)n = 1.8–2.8 and (Ce/Yb)n =3.9–6.1, results that rule out the crystallization ofthe Middle Banded series from a single magma type. Furthermore,the possibility that AN I and AN II are directly related tothe underlying Ultramafic series, either as flotation cumulatesor as crystallization products of expelled liquids, is not substantiatedby the REE data because the calculated parent magma of AN Iand AN II was different from that of the Ultramafic series asdefined by previous studies. The REE data of this study further constrain interpretationsof published Pb isotopic data (Wooden et al., 1991) and indicatethat the magmas from which the Stillwater Complex formed werederived from two sources that had only small differences inPb isotopic composition. The REE and isotopic data, as wellas crystallization sequences of the two main parental magmas,indicate that the magmas were probably derived from two closelyrelated upper-mantle sources, one harzburgitic and the otherlherzolitic in composition, resulting in the U-type and A-typemagmas, from which orthopyroxene crystallized before and afterclinopyroxene, respectively. Both sources had been enrichedin large-ion lithophile elements, probably owing to mantle metasomatism. 相似文献
19.
Y.T. John Kwong Steve Forgeron Robert J. MacDonald 《中国地球化学学报》2006,25(B08):30-30
The Sydney Coalfield is the largest in Atlantic Canada in which about 100 coal mines with varied lifespan have been opened since 1720. In the Glace Bay sub-basin, coal seams subcrop close to the Atlantic coast and dip seaward. Coal has been mined at 〉1200 m depth and 11 km from the coastline. Deposited possibly under a marine influence, the coals are enriched in pyrite. During mining abundant acidic sulfates such as melanterite, rozenite, copiapite and halotrichite have accumulated in the underground workings due to pyrite oxidation. The dissolution of these efflorescent salts upon mine flooding at closure gives rise to acidic mine pools wherever insufficient acid-neutralizing materials are present. A major challenge of mine decommissioning in the area is to prevent the discharge of this acidic water into the open ocean. Water monitoring in the 1B Hydraulic System, which consists of ten mines connected at various depths by natural or man-made conduits, shows that the mine pool chemistry varies with the mining practice employed. Although coal has invariably been mined by the room and pillar method, the extent of pillar removal varies from mine to mine. In mines with minimal pillar removal, coal extraction could be as low as 45%, leaving much pyrite for oxidation prior to eventual flooding and an acidic mine pool occurs. In contrast, in mines with extensive pillar removal, coal extraction could amount to 85%, leaving much less pyrite for oxidation. Moreover, the extensive pillar removal caused the collapse of the overlying strata which in some areas include limestone. The infilling of mine workings with carbonate-rich material offsets the effects of acidic effiorescent salts and a mine pool with near-neutral pH results. Geochemical modeling has affirmed the control of local water chemistry by the prevalent mineral assemblage. 相似文献