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研究区位处华北克拉通中部造山带,在中-新生代经历了多次构造体制与区域构造属性的重大转变。对吕梁山脉中北段古元古代花岗岩体隆升剥露的定量化研究,可以更加整体、直观的认识中部构造带内基底岩石隆升剥露作用,有助于了解华北克拉通演化过程。同时能为周围能源型盆地的形成演化提供佐证,深化对盆地资源赋存条件的认识,从而为资源的开发提供基础证据。通过对研究区古元古代花岗岩体系统的裂变径迹热年代学采样分析,揭示了基底岩石初始隆升剥露作用发生在晚白垩世至新生代早期,主要有两个阶段:白垩世晚期约88~77Ma和新生代早期约65~53Ma。之后,样品处在磷灰石退火带之上,虽有短暂的再次埋藏,但总体一直处在抬升剥露作用下。磷灰石裂变径迹数据和热史模拟表明,不同岩体抬升剥蚀在时空上具有非均衡性,晚白垩世早期,中部关帝山岩体呈穹隆状隆升剥蚀。北部芦芽山岩体和云中山岩体晚白垩世遭受挤压,发生隆褶变形。新生代以来,岩体加速隆升,早期(65~53Ma)是岩体抬升-剥露速率出现转折的关键时期,与东西两侧相邻断陷的发育具成因上的耦合联系,在华北地块中部地区具有区域响应,并可能奠定了现今吕梁山脉中北段的地势发展格局。 相似文献
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位于中央造山带西段的东昆仑造山带因多期次造山和复杂演化历史而备受关注,约束其中生代隆升剥露历史,对于理解青藏高原大规模隆升在东昆仑地区的扩展及影响颇具意义。东昆仑造山带内中生代侏罗系-白垩系地层缺失严重,体现中生代以来强烈的隆升剥露过程,也是该区热演化的研究难点。本文通过对东昆仑造山带样品的磷灰石、锆石裂变径迹分析和热演化史研究,并结合东昆仑及周缘地区现有低温热年代学研究,识别出东昆仑造山带所经历的五次隆升冷却事件,即201~193Ma（早侏罗世）、172~152Ma（中-晚侏罗世）、120~98Ma（早白垩世末-早白垩世初）、98~20Ma（晚白垩世-中新世）及20~0Ma（中新世至今）。所获5个年龄组响应东昆仑地区所经历的构造热事件,其中201~193Ma年龄组响应南部羌塘地块与昆仑地块的碰撞事件;172~152Ma年龄组为中-晚侏罗世古特提斯洋闭合后,造山后伸展的构造事件的记录;120~98Ma热事件吻合拉萨地块和羌塘地块碰撞事件;98~20Ma年龄组为东昆仑地区长期缓慢剥蚀去顶过程的印证;20~0Ma的快速隆升剥露事件则为东昆仑周缘断裂系活化相伴,多期隆升剥蚀事件均得到地层不整合及沉积记录等研究成果的证实。区内剥蚀起始时间从由南到北逐渐变老,体现东昆仑地区隆升剥蚀的不均一性。 相似文献
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东昆仑东段哈拉郭勒-哈图一带中生代的岩石隆升剥露--锆石和磷灰石裂变径迹年代学证据 总被引：4，自引：2，他引：4
根据对东昆仑地区东段哈拉郭勒—哈图一带不同高度基岩的系列锆石裂变径迹年龄分析，结合磷灰石裂变径迹年龄分析和中酸性侵入岩角闪石压力计分析揭示了东昆仑东段中生代的岩石隆升剥露冷却历史．巴隆哈图一带中酸性侵入岩角闪石压力计分析结果反映晚海西—印支期以来的总体剥露幅度约8～9km，早二叠世至晚三叠世初剥蚀作用极为缓慢，大约为20～40m／Ma．不同高程样品的锆石裂变径迹年龄分析结果揭示了东昆仑地区东段在中晚侏罗世处于缓慢的岩石隆升剥露阶段，其中中侏罗世相对较快，抬升速率77～88m／Ma，晚侏罗世相对较慢，抬升速率小于37m／Ma，且呈减慢趋势，这种减慢趋势反映了早中侏罗世之交强构造抬升期后的逐渐衰退．锆石裂变径迹—磷灰石裂变径迹年龄分析结果反映了中侏罗世以来的剥蚀速率一般不超过55m／Ma，岩石的剥蚀速率与岩石的抬升速率基本为同一量级，中侏罗世—白垩纪剥蚀作用与岩石抬升作用基本处于平衡状态。 相似文献
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石油地震资料揭示出塔里木盆地中央巴楚隆起为结晶基底和古生代地层相对隆升区,多数地区缺失中新生界,顶部为第四系陆相碎屑岩不整合覆盖隐伏隆起。在隆起南北两侧构造变形比较强烈,均发育基底卷入的逆冲构造和古生界内逆冲构造。运用断层相关褶皱理论,通过对研究区的二维地震测网解释及钻井标定,综合研究得出巴楚隆起北侧吐木休克卷入基底逆冲断层倾向南,向北逆冲,前寒武系基底到早古生代地层被错断。新生代时期的生长地层特征指示基底卷入构造于古近纪、中新世-上新世和更新世均有活动。构造分析表明基底卷入构造于中生代末期还有一次活动,说明吐木休克构造由多期构造运动形成。向北逆冲的吐木休克基底断层和盖层褶皱构造的向南反冲逆冲断层或滑脱断层共同组成基底卷入楔形构造,楔形点同时位于基底和盖层中。盖层构造以中寒武统膏岩为滑动面,向南逆冲,发育断层扩展或滑脱背斜构造。基底断层和盖层滑脱断层在剖面上组成典型的楔形构造几何形态,平面上形成三角形构造。地震剖面综合解释成果图显示,吐木休克弧形逆冲构造东部盖层反冲构造,即基底卷入楔形构造表现较为清楚,向西则表现不太明显,但地震反射波组(地层转折)指示盖层中仍存在这些反冲构造。纵向地震剖面和联络地震剖面均显示出存在该类构造。吐木休克基底卷入断层弧形构造顶部位移最大,盖层变形相对最小;向东西两侧基底断层位移逐渐减小,盖层构造位移相应逐渐增加。研究认为,塔里木巴楚隆起系挤压作用下,刚性地壳发生挠曲而形成的变形区带。 相似文献
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华北地块北缘晚古生代-中生代花岗岩体侵位深度及其构造意义 总被引：13，自引：5，他引：13
运用斜长石-角闪石温压计对华北地块北缘内蒙古隆起及燕山褶断带内不同时期花岗质侵入岩的结晶压力及侵位深度进行了估算。结果表明,晚古生代—早中生代期间,在内蒙古隆起及燕山褶断带之间,存在有强烈的差异性隆升及剥露过程,但这种差异性隆升及剥露在早侏罗世以来的表现则不明显。晚古生代—早中生代差异性隆升及剥露可能是导致内蒙古隆起上大量基底岩石出露、中—新元古代及古生代沉积盖层缺失及燕山褶断带中—新元古代及古生代沉积盖层大量保留的主要原因。内蒙古隆起强烈的隆升及剥露过程发生在晚石炭世—早侏罗世期间,其东部的剥露幅度比中东部明显偏小。晚古生代-早中生代期间内蒙古隆起的强烈剥露及其与燕山褶断带之间的差异性隆升可能与古亚洲洋板块向华北地块的俯冲、消减、碰撞及华北北缘区域性断裂(如平泉-古北口-赤城-尚义断裂、赤峰-围场-多伦断裂)的活动有关。燕山褶断带的强烈隆升与剥露发生则在晚侏罗世—早白垩世之后。晚体罗世—早白垩世以来,华北地块北缘南北两侧均有一次明显的剥露过程,这一剥露可能与本区及中国东部地壳强烈伸展有关。 相似文献
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循化-化隆盆地新生代沉积及盆地基底和周缘山系磷灰石裂变径迹年代学分析揭示了青藏高原东北缘晚白垩世以来经历过3期隆升剥露事件: (1)盆地基底及拉脊山和西秦岭北缘构造带磷灰石裂变径迹年龄分析普遍记录了晚白垩世-始新世中期相对快速的区域性的隆升剥露事件, 西秦岭北缘快速抬升的起始时间为84Ma, 受控于向北的逆冲抬升; 向北到循化-化隆盆地中部的拉目峡抬升的起始时间为69Ma; 更北的拉脊山一带快速抬升期主要为40~50Ma, 从而反映晚白垩世-始新世中期的快速抬升由南向北逐渐扩展.这一期构造隆升事件导致循化-化隆盆地和临夏盆地缺失了北部西宁-民和盆地古近纪所具有的西宁群沉积.隆升剥露结束于31Ma左右, 此时化隆-循化盆地向东与同时期的临夏盆地相连为一个统一的大型西秦岭山前盆地, 两者具有相同的构造、沉积演化史, 因此循化-化隆盆地他拉组底部地层年龄最老不会超过临夏盆地最老地层的古地磁年龄, 即29Ma.(2)渐新世晚期约26Ma拉脊山开始双向逆冲隆升, 并可能延续到中新世早期约21Ma, 隆升作用使循化-化隆盆地成为挟持于拉脊山逆冲带和西秦岭构造带之间的山前挤压型前陆盆地, 循化-化隆盆地开始大规模沉积巨厚的他拉组冲积扇相粗碎屑岩.(3)通过循化-化隆盆地咸水河组和临夏组的沉积相分析、古流方向和砾石成分分析, 揭示出拉脊山构造带在中新世8Ma左右发生的最大规模的双向逆冲隆升事件, 这次事件直接导致循化-化隆盆地由前陆挤压盆地转变为山间盆地, 形成现今青藏高原东北缘的盆山地貌基本格局. 相似文献
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天山南麓库车晚新生代褶皱-冲断带 总被引：2，自引：1，他引：1
库车褶皱冲断带位于天山南麓,由近东西走向的多条构造带组成。三叠系暗色泥岩、侏罗系煤层、古近系库姆格列木组膏盐层和新近系吉迪克组膏盐层构成库车褶皱冲断带的区域性主滑脱面。褶皱冲断带底面由北向南逐渐抬高。褶皱冲断带主体发育盖层滑脱-冲断构造(薄皮构造),基底卷入型冲断构造(厚皮构造)见于北缘的根带。新生界膏盐层之上构造变形以滑脱褶皱为特色,之下以冲断构造为特色。库车褶皱冲断带是印度-亚洲碰撞远程效应下,(南)天山晚新生代造山过程的产物。褶皱冲断带构造变形的动力来源主要是造山楔向塔里木盆地推进所形成的挤压构造应力。褶皱冲断带构造变形的起始时间为约23Ma,构造变形具有阶段式加速的特点,已经识别出约23Ma、约10Ma、5~2Ma和1~0Ma共4个变形加速期。褶皱冲断带的演化过程为前展式,褶皱冲断带前锋向南推进的同时,后缘持续变形。 相似文献
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《大地构造与成矿学》2015,(6)
板内多期构造变形与盆-山建造是板缘和/或板内构造动力学的综合体现,它们与隆升剥蚀和沉积建造等作用过程具有明显的响应与互馈。大娄山渐变型盆-山结构带地处中国扬子板块内部四川盆地南缘,为特提斯-喜马拉雅构造域和滨太平洋构造域的交接转换部位,走向NEE-NE,长~250 km、宽~80 km,缺少山前地形地貌陡变带,具渐变性山-盆地貌;浅部构造具挤压-坳陷结构,以隔槽式构造样式为主,构造变形缩短量约12~20 km。基于水平缩短变形、多期节理构造和古应力反演等揭示大娄山地区晚中生代-新生代发生了四期具不同应力场特征的构造变形事件与盆-山建造过程:第一期晚侏罗世-早白垩世近E-W向主应力场挤压变形事件;第二期晚白垩世(~80 Ma)近S-N向主应力场挤压变形事件;第三期古近纪晚期(40~20 Ma)NE-SW向主应力场挤压变形事件;第四期晚新生代(10~5 Ma以来)NW-SE向主应力场抬升剥蚀事件。大娄山渐变型盆-山结构带晚中生代-新生代的多期构造事件、中国南方大陆板缘主要板块事件、板内构造与隆升事件具有明显的相关性,表现为它们之间的沉积建造、构造和岩浆热事件、低温热年代学等具有一致性和同步性特征,共同揭示出区域晚中生代-新生代由滨太平洋构造域向特提斯-喜马拉雅构造域逐渐转换的重要过程。 相似文献
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冀东马兰峪背斜南翼与西部倾伏端盖层变形特征及其构造意义 总被引：2，自引：0，他引：2
燕山中部冀东遵化、迁西、青龙一带以太古宇深变质结晶岩系为核部的东西向构造形迹长期以来被认为是一个复式背斜构造,近年来又有学者提出它是一个中生代变质核杂岩。这2种不同认识涉及到华北克拉通北部中生代区域大地构造演化和稳定克拉通内部大型基底结晶岩系的剥露机制问题。对马兰峪背斜南翼和西部倾伏端盖层岩系开展的详细构造研究表明,变形总体表现为连续的褶皱变形及伴生的逆冲构造;构造样式表现为基底卷入式的厚皮构造与盖层内部软弱岩系控制的薄皮构造共存的特征;变形机制表现为顺层挤压导致的纵弯弯曲和相关的断裂构造;近南北向的缩短率介于16%～27%之间。盖层岩系中未发现变质核杂岩构造模型所预期的系列高角度正断层。基底与盖层不整合面接触带尽管在后期构造变形过程中曾经发生过局部的差异性滑动,但并不是造成大规模构造剥蚀和地壳柱切失的剥离断层。因此,冀东马兰峪背斜不是中生代的变质核杂岩,而是水平挤压背景下基底结晶岩系与盖层共同卷入纵弯褶皱变形的厚皮式褶皱构造。 相似文献
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S. Viswanathan K. Surya Prakash Rao B. Mahabaleswar 《Journal of the Geological Society of India》2013,82(6):621-627
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours. 相似文献
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奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提 相似文献
14.
E. M. Prasolov S. A. Sergeev B. V. Belyatsky E. S. Bogomolov K. A. Gruzdov I. N. Kapitonov R. Sh. Krymsky V. O. Khalenev 《Geochemistry International》2018,56(1):46-64
This paper reports the first results of a study of 11 isotope systems (3He/4He, 40Ar/36Ar, 34S/32S, 65Cu/63Cu, 62Ni/60Ni, 87Sr/86Sr, 143Nd/144Nd, 206–208Pb/204Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others. 相似文献
15.
Mining induced subsidence can significantly affect mining costs where major surface facilities and natural environment need to be protected. Overburden grout injection is a technology used to control coal mine subsidence by injecting the mine waste material extracted from the coal back into the inter-burden rock during longwall mining. The flowing slurry is here categorised as a nonlinear viscous cohesive (Bingham plastic) fluid. During longwall mining the grout slurry is pumped into the separated beds of the rock mass through a central vertical borehole, which is drilled deep into the inter-burden rock strata above the coal seam. However, a blockage can occur in the injection system when the slurry velocity falls below a certain critical threshold velocity, indicating a material phase change from cohesive-viscous to cohesive-frictional. In situ field injection tests through boreholes have been simulated at a smaller scale at the CSIRO laboratory in Brisbane by pumping the slurry through a radial disk (gap = 4 mm) from its centre. Laboratory experiments indicate a general, nonlinear, cohesive, viscous, frictional model for shear behaviour of the slurry, in which the material shear parameters are functions of the disk radial distance. Complete dimensional and dimensionless analytical solutions have been developed based on an approach related to Bingham–Herschel–Bulkley fluid mechanics. The derived formulae include relations for minimum pump pressure, local pressure and pressure gradient, wall shear stress, volume rate, velocity and velocity gradient. The theoretical results match the experimental measurements. The experiments covered slurries with maximum particle sizes of 0.5 to 2 mm with about 50% being larger than 100 µm. The viscosities at the various solids concentrations were measured with a standard torsion viscometer. This study differs from the previous research in several distinct aspects, namely, consideration of the variable shear parameters rather than fixed values, inclusion of total nonlinear behaviour, and implementation of a friction function to mimic behaviour of the deposited and consolidating stiff slurry, which can cause a significant pressure rise as a result of the increased shear resistance. 相似文献
16.
17.
Alexander E. C. Broberg J. S. Kehren A. R. Graziani M. M. Turri W. L. 《Environmental Geology》1993,22(4):353-361
Bellechester, Minnesota, is a small community of approximately 155 residents located on the county line between Goodhue and Wabasha counties in southeast Minnesota's karst region. Bellechester is served by a 21-year-old wastewater treatment facility (WWTF) consisting of three waste-stabilization ponds. On 28 April 1992 six sinkholes were discovered to have drained cell 2 of the WWTF resulting in the loss of approximately 8.7×106 1 of partially treated effluent and about 600 m3 of soil into previously undetected subsurface voids of unknown dimensions. In the week following the collapse, approximately 200 water wells located within a 5-km radius of the WWTF were sampled in an after-the-fact, emergency sampling program. Twelve samples with elevated fecal coliform levels, 18 samples with nitrate-nitrogen greater than the 10 mg/1 standard, and no samples with elevated chlorides were found. However, the elevated levels could not be unambiguously attributed to the WWTF collapse. This is the third WWTF to fail by sinkhole collapse in southeast Minnesota since 1974. All three collapsed lagoons have been located in similar geomorphic and stratigraphic settings. However, at least two lagoons have collapsed in the adjacent area in northeast Iowa, and these lagoons are located at different stratigraphic positions. Twenty-two WWTFs constructed in southeast Minnesota's karst region in the last 25 years have been identified as subject to potential sinkhole collapse. An unknown but significant number of manure storage lagoons, flood control structures, etc., have also been constructed in the karst region and are at risk. Public agencies are beginning to develop plans to deal with the risk associated with existing and future waste lagoons in this environment. The critical hydrogeologic parameters that can be used to prioritize the risk of collapse at existing facilities include: (1) the lithology of the first bedrock beneath each lagoon, (2) the thickness of surficial materials between the lagoon and the bedrock surface, (3) the presence and construction of liners (seepage rate), and (4) the proximity to existing sinkholes. 相似文献
18.
Mercury,arsenic, antimony,and selenium contents of sediment from the Kuskokwim River,Bethel, Alaska,USA 总被引：1，自引：0，他引：1
The Kuskokwim River at Bethel, Alaska, drains a major mercury-antimony metallogenic province in its upper reaches and tributaries. Bethel (population 4000) is situated on the Kuskokwim floodplain and also draws its water supply from wells located in river-deposited sediment. A boring through overbank and floodplain sediment has provided material to establish a baseline datum for sediment-hosted heavy metals. Mercury (total), arsenic, antimony, and selenium contents were determined; aluminum was also determined and used as normalizing factor. The contents of the heavy metals were relatively constant with depth and do not reflect any potential enrichment from upstream contaminant sources. 相似文献
19.
滇东南锡、银、铅、锌多金属矿床主要分布在个旧、白牛厂、都龙3个矿区,而滇东南较大的3个花岗岩体又分别出露在3个矿区或附近.花岗岩体均形成于燕山晚期,岩石化学、矿物成分相似,富含锡、银、铅、锌、钨、铜等成矿元素.矿床主金属元素组合与岩体之间的距离由远而近出现由锡、钨、(铍、铌、钽)→锡、钨、(铁)、铜、铟→锡、铅、锌、银、铟、(锑)有规律的变化.花岗岩浆是成矿物质来源和成矿热源.岩浆侵入初期使上覆地层隆起产生背斜(凹陷部位成向斜);同时使地层产生一系列裂隙、压性断层或层间断裂;岩浆侵入晚期,这些断层再次活动,表现为张性,岩浆产生的含矿热液沿由其活动所造成的断裂迁移、充填、交代、沉淀而形成矿床. 相似文献
20.
岩石密度和超高压岩石折返速率 总被引：1，自引：3，他引：1
在常温常压条件下对中国大陆科学钻CCSD主孔100-3000米岩心样品进行了密度测量,建立了密度连续剖面,并界定了不同超高压岩石的密度值。通过对比高温高压物性实验资料,岩石密度随着退变程度增强而降低,榴辉岩密度变化序列为3.52g/cm3→3.49g/cm3→3.07g/cm3→2.93g/cm3。超高压长英质岩石密度变化序列为3.00g/cm→2.80g/cm3→2.65g/cm3。上述实验资料是讨论不同折返阶段岩石所受浮力的基础,为研究折返速率大小提供了基本参数。本文通过折返板块运动平衡时,上浮力与粘滞力平衡这一关系式,定量研究了大陆俯冲板块的折返速率,认为密度差产生上浮力从而引起折返,温度对板块折返速率的影响最为显著;密度差大小、折返角度、折返板块大小对折返速率也有直接的影响。定量模拟分析表明,在温度高于850℃时,板块的折返速率可以超过100mm/a;当温度降至700℃时,折返速率则低于1.5mm/a。作者认为在折返早期,温度较高,板块快速折返至60-70km榴辉岩相深度;随着传导散热,温度降低,板块以较慢的速率折返至中下地壳。折返速率的估算表明,浮力是板块折返第一阶段(从>100km深部折返至<40km的中下地壳)的主要驱动力。 相似文献