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基于横穿南极半岛西侧不活动陆缘陆架区的多道地震剖面解释,对该地区的新生代构造变形及沉积演化进行了研究。研究表明,南极半岛西侧陆缘陆架区可以划分为四大平行于南极半岛走向的构造单元,从陆侧至海侧,分别是陆架内缘区、陆架盆地、陆架中部隆起和陆架外缘区。同时通过地震剖面不整合面识别以及结合区域演化历史,对陆架外缘区层位进行了划分,共划分出四大构造层序：俯冲碰撞前层序S4,俯冲碰撞后层序S3,上新世冰川沉积S2及全新世冰海沉积S1。基于构造单元及构造层序的划分,将南极半岛西侧不活动陆缘陆架区的构造沉积演化分为三期：（1）中生代—始新世,菲尼克斯板块向着南极半岛俯冲,南极半岛西侧陆缘为主动大陆边缘,陆架内缘区发生火山活动,形成海底火山岩,而在陆架盆地区和陆架外缘区沉积火山碎屑岩;（2）从始新世开始,南极洲菲尼克斯洋中脊逐步分段式地抵达南极半岛西侧大陆边缘,南极半岛西缘逐渐转变成不活动的大陆边缘,并在陆架中部发生隆起作用,使得陆架盆地内的沉积物发生变形形成向斜构造,同时在陆架外缘区沉积硅质碎屑岩;（3）上新世开始,南极半岛西缘发生大规模的冰川作用,大陆边缘的沉积主要受控于冰川作用。 相似文献
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在分析海底地貌学国内外研究现状基础之上,综述我国海底地貌的最新研究进展和发展历程,探讨今后我国近海地貌的研究发展方向:我国现代海底地貌学研究虽然起步较晚,但总的趋势是随着测量技术的不断更新,由宏观向微观、从大的地貌类型向特定的地貌体、从形态特征到地貌过程的研究,并着重研究人类活动与地貌过程的响应关系。针对"908专项"在我国近海海域的调查成果,着重介绍其在我国东海近海海域地形地貌研究中的新发现、新认识:长江口外古潮流沙脊群可分为堆积型、侵蚀—堆积型和侵蚀型潮流沙脊群3种类型;在福建闽江口近岸的马祖列岛和白犬列岛之间发现多条呈SW—NE走向、条带状分布的潮流沙脊,面积约200 km2,水深在15～30 m;在东海陆架沙脊区与金门岛外发现2处新的海底礁石。这些全新的发现和认识对于我国近海海底地貌的研究将起到丰富和推动作用。 相似文献
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通过分析珠江口盆地惠州凹陷新近系珠江组NE—SW向平行于古岸线展布的K22条带状砂体外部地震反射特征、内部反射结构及平面展布规律,并运用层序地层学方法和理论,结合海平面变化特点,对K22条带状砂脊沉积成因进行了研究。结果显示:K22条带状砂脊为发育在陆架区古构造高带、受控于强制性海退过程的再沉积产物,其物源来自于早期的三角洲,沉积水动力条件多样,主要为海退过程中的潮汐流和波浪作用;同时,沿岸流也对砂脊形态的形成起到了关键作用,这些砂脊后期得益于快速的海侵而保留下来。留存下来的沙脊沉积被包裹在海相泥岩背景中,可形成良好的岩性圈闭。 相似文献
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《地学前缘》2017,(5)
基于横穿南极半岛西侧不活动陆缘陆架区的多道地震剖面解释,对该地区的新生代构造变形及沉积演化进行了研究。研究表明,南极半岛西侧陆缘陆架区可以划分为四大平行于南极半岛走向的构造单元,从陆侧至海侧,分别是陆架内缘区、陆架盆地、陆架中部隆起和陆架外缘区。同时通过地震剖面不整合面识别以及结合区域演化历史,对陆架外缘区层位进行了划分,共划分出四大构造层序:俯冲碰撞前层序S4,俯冲碰撞后层序S3,上新世冰川沉积S2及全新世冰海沉积S1。基于构造单元及构造层序的划分,将南极半岛西侧不活动陆缘陆架区的构造-沉积演化分为三期:(1)中生代—始新世,菲尼克斯板块向着南极半岛俯冲,南极半岛西侧陆缘为主动大陆边缘,陆架内缘区发生火山活动,形成海底火山岩,而在陆架盆地区和陆架外缘区沉积火山碎屑岩;(2)从始新世开始,南极洲-菲尼克斯洋中脊逐步分段式地抵达南极半岛西侧大陆边缘,南极半岛西缘逐渐转变成不活动的大陆边缘,并在陆架中部发生隆起作用,使得陆架盆地内的沉积物发生变形形成向斜构造,同时在陆架外缘区沉积硅质碎屑岩;(3)上新世开始,南极半岛西缘发生大规模的冰川作用,大陆边缘的沉积主要受控于冰川作用。 相似文献
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基于Rio Muni盆地深水区1 400 km2的高分辨率三维地震资料,对第四纪陆坡开展地形、地貌单元的构型、成因及演化研究。主要取得3点结论:①依据海底坡度,研究区海底地形具有东西分带,南北分区的特点。②研究区发育水道（顺直水道和弯曲水道）、滑坡（陆坡滑坡和水道壁滑坡）及海底麻坑（孤立麻坑和条带状麻坑）3类典型地貌单元。上陆坡主要发育顺直水道,弯曲水道带发育在中-下陆坡。弯曲水道主要分布在南北2区,而顺直水道在南中北3区均有发育。水道的弯曲程度与海底坡度、重力流供给密切相关。③条带状海底麻坑主要分布在南北2区,孤立麻坑3区均发育。单一麻坑任意方向的剖面均具有“U”形或“V”形特征,其下方的气烟囱具有振幅增强,同相轴下拉特征。条带状麻坑分布在古水道上方或两侧的海底, 其走向剖面具有脊-槽相间地形特征。古水道和浅层气的逸散是形成条带状海底麻坑的主要因素。 相似文献
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舟山海域海砂资源声地层剖面探测研究 总被引：1，自引：0，他引：1
在对研究区实测声地层剖面资料进行分析解释的基础上,对比地质浅钻资料,将浅部地层划分为四个地震相单元,对研究区浅地层的沉积格架有了进一步的认识。对区内海底潮流沙脊、沙席、埋藏潮流沙脊、海底沙波等砂质地质体的地质特征有了较深入的了解,并对砂矿的物质来源、成因进行了讨论,揭示出本区砂体近源沉积、快速堆积的特点。 相似文献
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南海盆地是东南亚陆缘最大的、含有丰富油气等资源的边缘海盆地.对于南海大陆斜坡带的发育、沉积演化与南海盆地构造作用及动力学过程的响应关系等方面缺乏深入认识.依据地震、测井及岩心等丰富资料,对南海珠江口盆地东南部陆架边缘斜坡带的层序地层、沉积-地貌演化及其对构造、海平面和沉积物供应变化的响应关系开展了系统性的研究.研究表明盆地的沉积充填可划分为由区域性不整合所限定的7个复合（二级）层序（CS1-CS7）.复合层序CS3-CS7（上渐新统-第四系）均由区域性的海侵-海退旋回构成;其内可进一步划分出由局部不整合或水退-水进的转换面为界的20个次级层序（三级）.研究识别出包括外陆架至陆架边缘三角洲、前三角洲-斜坡扇、陆架边缘前积体、单向迁移的横向底流-斜坡重力流复合水道、大型斜坡下切峡谷、泥质斜坡扇、斜坡滑塌泥石流复合体以及大规模软沉积物变形体等沉积体系或沉积复合体,它们在不同层序具有特定的时空分布,构成多种沉积样式.短周期（三级）的沉积旋回变化与Haq的海平面变化曲线总体上可对比,但长周期的海侵和海退则明显不同,受到了构造隆升和沉降等的控制.陆架边缘沉积演化可划分出裂后早期海底扩张沉积（破裂层序）、裂后晚期海底扩张沉积、后海底扩张等构造-沉积演化阶段.裂谷作用晚期的热隆起、构造差异沉降、裂后热衰减沉降以及上新世以后的东侧碰撞等对主要不整合的形成和海侵-海退产生了重要的影响.晚渐新世至中中新世发育的复合层序（CS3和CS4）记录了裂后海底扩张到停止的大陆斜坡沉积过程;而裂后早期的沉积层序（CS3）为破裂层序,以发育大型的陆架边缘三角洲-前三角洲斜坡扇体系构成的前积层为特征.气候变化和季风加强可能增强了晚渐新世-早中新世和更新世沉积期的沉积物供应,为大规模陆架边缘三角洲体系的发育提供了充足的物源供给.发育于陆架边缘的三角洲-滨岸碎屑体系和共生的前三角洲斜坡扇体系构成区内最重要的油气勘探对象. 相似文献
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南海晚中新世-上新世红河沉积体系研究 总被引：1，自引：0，他引：1
红河沉积体系为南海西北部近期新发现的大型远源沉积体系,其主要发育于南海莺歌海盆地和琼东南盆地。重点利用大量二维地震剖面资料,根据地震反射特征对晚中新世-上新世红河沉积体系的识别特征以及平面展布进行了研究,以此为基础划分了红河沉积体系在晚中新世-上新世演化阶段。研究结果表明:通过地震反射特征的分析,可以识别出三角洲、水下下切水道、海底峡谷、水道堤岸复合体以及海底扇朵体等沉积;依据红河沉积体系的平面组合和展布特征,可将晚中新世至上新世的红河沉积体系演化划分为3个阶段:10.5～5.5 Ma（SQ1、SQ2）为红河海底扇发育阶段,以发育大型“三角洲-水下下切水道-海底扇”为特征;5.5～3.6 Ma（SQ3、SQ4）为限制性海底扇-中央峡谷发育阶段,以先发育限制性海底扇,后发育大型海底峡谷为特征;3.6～1.8 Ma（SQ5、SQ6）为红河沉积体系衰弱阶段,在研究区内以红河沉积体系主体不发育,海南岛陆坡发育为特征。红河沉积体系是青藏高原隆升的产物,研究红河沉积体系除有利于制定油气勘探方向外,还有助于青藏高原隆升历史恢复、红河袭夺等问题的研究。 相似文献
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塔里木盆地顺托果勒低隆起志留系柯坪塔格组下段发育的陆架砂脊为了解古陆架砂脊沉积建造提供了一个理想实例.利用测井和岩心资料, 根据沉积物的岩性和沉积构造特征, 将陆架砂脊划分为6个岩性相: 块状层理中-细砂岩性相(FA1)、丘状交错层理中-细砂岩性相(FA2)、含撕裂状泥砾的中-细砂岩性相(FA3)、双向交错层理含粘土层的细砂岩性相(FA4)、潮汐层理的细砂岩与泥岩互层岩性相(FA5)和水平层理陆架泥岩性相(FA6);依据岩性相的组合特征, 将陆架砂脊划分为4个沉积微相: 砂脊核微相(FA1-FA2-FA3)、砂脊内缘微相(FA4)、砂脊外缘微相(FA5)和陆架泥微相(FA6);陆架砂脊沉积受陆架潮汐、风暴浪的共同影响.利用钻井约束的三维地震切片属性分析, 确定了NE-SW向和NW-SE向两组古陆架砂脊的平面展布特征.古陆架砂脊储层为特低孔、特低渗, 其中砂脊核微相储层物性相对较好, 平均孔隙度6.96%、平均渗透率0.34×10-3 μm2; 工业油流主要集中在砂脊核微相储层.古陆架砂脊的砂体多呈脊状或丘状并被厚层的陆架泥披覆, 常形成同沉积的微幅背斜-岩性圈闭. 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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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
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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
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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
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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.
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
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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