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1.
风暴岩对于古地理和古环境具有良好的指相意义。东海盆地西湖凹陷天台区始新世平湖组发育典型的风暴岩。通过详细的岩心观察,发育的风暴沉积标志主要有冲刷-充填构造、风暴撕扯构造和丘状-洼状交错层理构造等。根据风暴岩垂向上的组合特征及沉积构造差异,识别出了近源和远源两种风暴沉积类型,分别指示了不同的沉积背景:近源风暴岩表现为不完整的风暴岩垂向沉积序列,呈风暴砾屑层段(A)+泥岩段(E)叠加,为潮坪潮下带沉积;远源风暴岩具完整和不完整的风暴岩垂向沉积序列,以粒序段(B)+平行层理段(C)+丘状(洼状)层理段(D)叠加为特征,属浅海陆棚沉积。风暴层序自下而上沉积环境为浅海陆棚→潮坪,风暴岩的分布差异表明形成环境向上变浅的沉积特征。该发现为本区古环境的演变提供了重要依据。  相似文献   

2.
龙门山甘溪组谢家湾段风暴岩沉积特征及其意义   总被引:3,自引:2,他引:1       下载免费PDF全文
通过野外剖面测量、采样和室内鉴定,建立了甘溪剖面泥盆系岩石学、古生物学和沉积构造等沉积相标志,对甘溪剖面泥盆系甘溪组风暴岩进行系统研究。本剖面风暴岩沉积特征很典型,各种与风暴流有关的沉积构造非常发育,可划分出近源和远源风暴流沉积2个类型。风暴岩的发现有利于加深对该区沉积相的认识,风暴岩的频繁发育,表明研究区在泥盆系沉积时,曾经处于易受到古大洋气候影响的低纬度区域,由于风暴作用是瞬时间的等时性事件,风暴沉积序列可以作为"明显的等时意义"地层对比的重要标志。因此,该项研究成果对重塑龙门山地区古海洋学、古气候学的研究,对恢复古板块位置等都十分重要。  相似文献   

3.
龙门山地区泥盆纪地层中含有种类丰富、数量众多的海相遗迹化石。以野外剖面实测为基础,对北川甘溪石沟里剖面中泥盆统养马坝组风暴沉积中的遗迹化石进行了系统描述,共识别出5种类型的遗迹化石属种,包括Chondrite、Changchengia、Rhizocorallium、SkolithosZoophycos。根据遗迹化石的组合特征,将其划分为Chondrites-Zoophycos遗迹化石组合类型,反映了受风暴影响的浅水沉积环境。通过遗迹化石的分布位置、相互间的切割关系,建立了龙门山地区石沟里剖面养马坝组风暴岩中各种遗迹化石形成的先后顺序,依次为Chondrites、Zoophycos、Rhizocorallium、ChangchengiaSkolithos。发育于风暴岩中的ChondritesZoophycos遗迹化石,具有鲜明的机会种特征,对沉积环境有重要的指示意义。保存于龙门山地区泥盆系养马坝组风暴岩中丰富的具细小分支直径的Chondrites遗迹化石,反应水体氧含量并非控制Chondrites潜穴直径大小的唯一控制因素,可能与造迹生物生活环境的恶劣与否间存在着一定关系;风暴沉积中发育的Zoophycos遗迹化石,指示其在泥盆纪可以沉积于浅海环境。  相似文献   

4.
通过对四川盆地龙门山区甘溪石沟里剖面实测,建立了石沟里剖面泥盆系养马坝组风暴沉积的识别标志,进而对其风暴岩进行了系统研究。石沟里养马坝组风暴沉积的重要标志包括冲刷面、渠模等风暴侵蚀构造和粒序层理、平行层理、丘状交错层理等风暴浪构造。该区养马坝组发育了6种类型的风暴沉积单元组成序列,据此建立了完整的风暴序列模式,由粒序层理段(Sa)、平行层理段(Sb)、丘状交错层理段(Sc)、波状层理段(Sd)和泥岩段(Se)组成,底部常发育冲刷面和渠模构造。龙门山区甘溪石沟里养马坝组风暴沉积可分为近源风暴和远源风暴2种类型,依据风暴沉积的剖面结构类型和沉积构造特点,建立了该区风暴沉积序列的分布模式。龙门山区甘溪石沟里养马坝组发育的风暴沉积是该区混合沉积发育、抑制生物礁发育的重要控制因素,对于该区古地理重建具有重要的指示意义。  相似文献   

5.
山东惠民凹陷古近系风暴岩沉积特征及沉积模式   总被引:13,自引:4,他引:9  
袁静 《沉积学报》2006,24(1):43-49
利用钻井取心、薄片鉴定、粒度分析及测井解释等资料和手段,对惠民凹陷古近系风暴岩进行研究。结果表明,该凹陷风暴岩岩石类型丰富,包括各类碎屑岩、生物灰岩和火山碎屑岩。粒度分布具有“高斜多跳一悬式”、多段式和高斜一段式等多种样式。沉积构造也反映出重力流和牵引流兼有的水动力机制,发育渠模、冲刷面和截切构造等底层面侵蚀构造,递变层理、块状层理、丘状层理、洼状层理、平行层理等层理构造,波痕和各种同生变形构造、生物逃逸构造等。研究区风暴岩理想的垂向层序从下至上可抽象为“似鲍玛序列”:Sa递变层理段,Sb较大型浪成交错层理段,Sc平行层理段和丘状交错层理粉砂—细砂岩段,Sd波状纹层段,Se泥岩段和Sf正常半深湖泥页岩段。主要根据风暴岩的垂向序列类型、沉积构造特点和原地沉积物特征等总结出九种风暴岩序列和原地风暴岩、A型近源风暴岩、B型近源风暴岩和远源风暴岩等四种风暴岩沉积模式。  相似文献   

6.
通过对北京西山下苇甸剖面中典型风暴成因竹叶状灰岩的野外实测和镜下薄片分析,明确了59套风暴沉积特征,确定了风暴沉积序列并建立了陆表海风暴作用沉积模式,主要取得如下认识:(1)北京西山下苇甸寒武系共有泥晶灰岩相、含砾屑泥晶灰岩相、颗粒泥晶灰岩相和泥晶颗粒灰岩相4种岩相类型。(2)鲕粒灰岩-砾屑灰岩型序列发育原地型风暴岩,泥岩和粉砂岩-砾屑灰岩型序列发育近源型风暴岩,泥晶灰岩-砾屑灰岩型序列发育远源型风暴岩。(3)原地型风暴岩发育侵蚀面,砾屑含量高,长短轴比大;近源型风暴岩砾屑定向性好,可见递变层理;远源型风暴岩基质含量高。(4)竹叶状灰岩沉积在陆表海背景下的潮下带,原地型、近源型和远源型风暴岩沉积范围以正常浪基面和风暴浪基面为界,距风暴中心距离和搬运距离依次增加。本次研究不仅补充了下苇甸寒武系的风暴沉积记录,而且为该时期的古环境研究提供了证据。  相似文献   

7.
鄂东黄石地区下三叠统大冶组风暴沉积   总被引:4,自引:3,他引:1  
鄂东黄石地区下三叠统大冶组灰岩中发育了典型的风暴沉积,风暴岩由砾屑灰岩、颗粒灰岩和泥灰岩组成,其中风暴沉积构造包括丘状交错层理、递变层理、砾屑的撕裂构造及水平层理等,不同层位具有不同的风暴沉积构造类型和组合特征。根据风暴沉积的岩石特征、构造类型、规模、组合特点,并结合沉积背景分析,风暴沉积序列可进一步分为深水远源型、过渡型和浅水近源型。大冶组一段风暴沉积具有深水远源特点,沉积环境为水体较深的外陆棚; 大冶组二段风暴沉积具有过渡型特点,沉积环境为向上变浅的内陆棚; 大冶组三、四段风暴沉积具有浅水近源特点,沉积环境为浅水陆棚至滨岸。大冶组沉积序列具有向上变浅的特点,沉积环境由深水陆棚逐渐向滨岸转变。风暴沉积的识别对重建鄂东黄石地区早三叠世古地理具有重要意义。  相似文献   

8.
薛武强  李波  颜佳新  申欢欢 《沉积学报》2012,30(6):1010-1020
黔南罗甸沫阳剖面中二叠世茅口组以海相碳酸盐为主,下部地层中发育风暴岩,露头特征明显,主要以介壳灰岩为识别标志。风暴沉积构造包括底面侵蚀构造、截切构造、波痕层理、递变层理、块状层理等。风暴沉积主要包括一个底面构造A和B、C、D、E等四个沉积单元:A.侵蚀底面,代表风暴流对海底沉积物的作用;B.介壳灰岩层,代表风暴浪、风暴涡流沉积;C.粒序层,代表风暴衰减期重力分异沉积或风暴浊流沉积;D.块状层,代表风暴快速悬浮沉积;E.波痕层理段,代表风暴衰减后期沉积。它们共组成4种风暴沉积序列,分别代表不同深度的风暴沉积,反映了不同的风暴沉积作用和风暴流的类型。沫阳地区风暴沉积的沉积特征表明,该区风暴沉积主要发育于风暴浪基面之上的内陆棚沉积环境,风暴强度大,为近源风暴岩。仅个别风暴沉积发育于风暴浪基面之下的外陆棚沉积环境,为风暴引起的浊流沉积,为远源风暴岩。风暴岩类型的正确识别,对确定该区沉积相与深入认识扬子碳酸盐台地南部边缘沉积演化提供参考依据。  相似文献   

9.
三峡地区志留纪纱帽组风暴岩的发现及地质意义   总被引:3,自引:0,他引:3  
通过对三峡地区志留纪纱帽组的系统研究,在不同层位上,划分出了砂质、灰质、钙屑、含磷质等4种类型风暴岩。经过其结构特征、沉积序列、沉积相等分析,认为砂质风暴岩和含磷质风暴岩隶属近源风暴岩,灰质风暴岩隶属远源风暴岩,钙屑风暴岩则属于上述两者间的过渡类型。研究区内4种类型的风暴岩在横向上分布广,纵向上风暴作用持续时间短,沉积速率大,并且结构特征明显,便于追索和对比,可作为等时性标志层进行地层对比。  相似文献   

10.
龙门山中段产出有泥盆系沙窝子组的什邡式磷矿、寒武系筇竹寺组清平式磷矿、震旦系观音崖组陡梯子式磷矿,三类矿床处于同一大地构造位置,地质特征既有区别也有相同之处。本文通过对三类矿床地质特征、矿床成因分析,探讨地质特征异同的原因,建立磷矿成矿序列,认为三类矿床各自既有原生同沉积特征,又有继承前期矿产或含磷层作为矿物源的特征,继承前期矿产越多,矿床越丰富,具递进成矿富集规律。同时早期矿床成矿作用较单一,后期矿床具有多期成矿、叠加成矿特征。成矿序列为:海水磷质生物、化学沉积-机械搬运簸选早期成矿-风化剥蚀、表生淋滤-再次机械搬运-海进沉积再造。  相似文献   

11.
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   

12.
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   

13.
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   

14.
本文介绍样品经四硼酸锂熔融制成玻璃小饼。采用Lachance模式和理论a系数来校正元素间的效应,由3080E型X-射线荧光谱仪和DF-350B数据处理系统完成硅酸盐中十三个项目的测定。  相似文献   

15.
本文拟定了一种以熔融法制备样片,用X射线荧光光谱测定硅酸盐类样品中Si、Fe、Al、Tj、Mn、Ca、Mg、K、Na、P等元素的分析方法。在对不同靶材X光管和分光晶体实验对比的基础上,选择了最佳的测量条件。该法具有快速、准确,测量范围广,检测限低,价格便宜等优点。经过近百个各种类型标样或管理样品的分析对比表明,本法不仅适用于硅酸盐类岩石样品的分析,还适用于铁矿、铝土矿、碳酸盐类岩矿样品以及水泥、耐火材料等样品的分析。  相似文献   

16.
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   

17.
18.
Between 1985 and 1991, two new mountain protected areas (MTNPA) covering more than 35,000 km2 and based on participatory management models — the Makalu-Barun National Park and Conservation Area, Nepal, and Qomolangma Nature Preserve, Tibet Autonomous Region — were successfully established through the collaborative efforts of Woodlands Mountain Institute and conservationists in China and Nepal. Characteristics common to both projects include the importance of establishing (1) effective rationales, (2) local support constituencies, (3) a senior advisory group, (4) a task force, (5) linkages between conservation and development, and (6) fund raising mechanisms. The lessons derived from the experiences of Woodlands Mountain Institute are of significant value to others in preserving MTNPA. Increased collaboration and communication between all interested in conservation, however, will remain a critical component for expanding mountain protected area coverage to throughout the world.  相似文献   

19.
《Applied Geochemistry》2001,16(2):137-159
Five hundred and ninety-eight samples of terrestrial moss (Hylocomium splendens and Pleurozium schreberi) collected from a 188,000 km2 area of the central Barents region (NE Norway, N Finland, NW Russia) were analysed by ICP-AES and ICP-MS. Analytical results for Al, B, Ba, Ca, K, La, Mg, Mn, Na, P, Rb, Si, Sr, Th, U and Y concentrations are reported here. Graphical methods of data analysis, such as geochemical maps, cumulative frequency diagrams, boxplots and scatterplots, are used to interpret the origin of the patterns for these elements. None of the elements reported here are emitted in significant amounts from the smelting industry on the Kola Peninsula. Despite the conventional view that moss chemistry reflects atmospheric element input, the nature of the underlying mineral substrate (regolith or bedrock) is found to have a considerable influence on moss composition for several elements. This influence of the chemistry of the mineral substrate can take place in a variety of ways. (1) It can be completely natural, reflecting the ability of higher plants to take up elements from deep soil horizons and shed them with litterfall onto the surface. (2) It can result from naturally increased soil dust input where vegetation is scarce due to harsh climatic conditions for instance. Alternatively, substrate influence can be enhanced by human activity, such as open-cast mining, creation of ‘technogenic deserts’, or handling, transport and storage of ore and ore products, all of which magnify the natural elemental flux from bedrock to ground vegetation. Seaspray is another natural process affecting moss composition in the area (Mg, Na), and this is most visible in the Norwegian part of the study area. Presence or absence of some plant species, e.g., lichens, seems to influence moss chemistry. This is shown by the low concentrations of B or K in moss on the Finnish and Norwegian side of the (fenced) border with Russia, contrasting with high concentrations on the other side (intensive reindeer husbandry west of the border has selectively depleted the lichen population).  相似文献   

20.
We have developed a set of four synthetic standards for the rare earth and high field strength elements designed for use in the determination of those elements in silicates. The base material is a glass nominally at the eutectic of the MgO-Al2O3-SiO2 ternary system. The nominal doping level was 2 wt% of the elements as oxides. To avoid problems associated with peak interference, the elements were doped in four separate glasses.  相似文献   

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