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1.
准噶尔盆地阜东斜坡区侏罗系测井沉积相研究 总被引：4，自引：4，他引：4
本文就准噶尔盆地阜东斜坡区侏罗系测井沉积相研究进行了探讨。主要应用常规测井资料、地层倾角测井资料及成像测井资料为核心的测井相序列去分析和判断沉积类型以及沉积相。经过ANN岩相处理，看出典型的三角洲沉积岩相序列自下而上依次为三角洲前缘远砂坝、河口砂坝、分流间湾、水下分流河道、分之河道及分之河道间，将其结果与录井剖面对比，符合率非常高，为区域上关键井的相序分析及沉积体系分析提供了连续的较准确的岩相依据。通过古水流系统的确定，看出研究区侏罗系八道湾组-三工河组沉积时期的物源主要来自北部克拉美丽山以北地区。南部北三台地区以南存在次要物源。最后综合利用常规测井处理解释的岩性剖面、岩心刻度下处理出来的沉积学倾角解释成果（沉积构造和古水流）和ANN岩相处理解释成果，建立起了阜东斜坡区关键井目的层段的测井沉积亚、微相模型。 相似文献
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准噶尔盆地西北缘车排子地区侏罗系物源及古水流分析 总被引：16，自引：8，他引：16
通过岩石岩屑组分分析、重矿物组分分析、倾角测井、地层厚度分析等方法，对准噶尔盆地西北缘车排子地区侏罗系进行物源及古水流方向分析。岩屑组分分析指示着大致的物源前进方向，重矿物分析明确了物源泄入的主要通道，倾角测井在单井点处对古流向有相当高的表现精度，但这三种方法均存在数据平面覆盖率较低和分布密度差异大的缺陷，而运用地震层位解释所得的地层等厚度图则可以在较大尺度上的二维平面内推测沉积时期的古地形，进而可以推测古流向，但它仅是一种间接预测方法，存在局部古流向预测精度较低的不足。文中综合各种方法，将直接预测方法的高精度和间接方法的高覆盖能力结合起来，对古流向作出较高精度的预测。在古流向研究的基础上建立了冲积扇－辫状河－河泛平原沉积体系的沉积相模式。该模式认为对于水流能量保持能力差的冲积扇，其古流向应该沿短轴陡坡降方向，即大致为SEE方向，而对于水流能量保持能力较强的辫状河来说，其古流向应该沿长轴缓坡降方向，即为SE甚至SSE方向。该模式的提出对于提高地震相－沉积相的转相精度具有一定的指导意义。 相似文献
3.
甘肃兰州-民和盆地是中国西部典型的陆内断陷沉积盆地,该盆地发育的下白垩统河口群是一套以红褐色为主的碎屑岩地层。依据野外调查,以盆地分析方法为手段,从地层、沉积相、物源和古水流等方面入手对盆地东南部的中铺地区河口群进行了沉积环境的系统分析。通过对研究区内河口群沉积相、沉积构造和沉积序列的研究,认为整套地层垂向上发育有冲积扇相-辫状河相-曲流河相沉积,并进一步划分出若干微相;同时结合该地区的物源和古水流分析认为,早白垩世研究区内的物源主要来自南部的祁连山多旋回造山带;盆地内的下白垩统河口群在不同地区呈现出不同特点,并以此建立了兰州-民和盆地早白垩世古地理格局及盆地演化模式。 相似文献
4.
湘西黔东寒武纪等深流沉积 总被引：9，自引：0，他引：9
本文描述了湘西黔东地区寒武纪沉积的等深岩类型和特征。对砂质等深岩和泥砂质等深岩层序的形成过程进行了讨论。分析了等深岩中交错层理反映的古流向资料,结合古地理背景,建立了工作区等深流沉积模式。 相似文献
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日喀则群砂泥质复理石的浊积层序非常发育,包括富泥的粘性高密度浊流、砂质高密度浊流、低密度浊流和Pickering及Hiscott(1986)的限制性泥质高密度浊流的沉积层序。其中,低密度浊流沉积层序的组合与鲍马(Bouma)层序很相似,两者的区别在于沉积的粒度、粒级分布范围、层序厚度和相组合等特征的不同。沉积相序、古流向和物源分析表明,日喀则群复理石盆地的南侧主要发育单向物源的海底扇体系,而盆地北侧以发育双向物源和多种沉积流体的复合沉积为特征。值得指出的是,特殊的浊积类型——限制性泥质高密度浊流沉积的发现为论证日喀则群复理石盆地属残留盆地又提供了一条有力的依据。 相似文献
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造山带动力沉积学是造山带地质学和大陆动力学研究的重要方面。造山带动力沉积学研究的重要基础是识别造山带的原型沉积盆地,认识其大地构造沉积相和原型沉积盆地的演化。造山带动力沉积学研究的主要内容包括造山带区域地层学、沉积学、大地构造学、造山带原型盆地的充填序列或构造层序、古地理和古海洋及建立沉积盆地的动力模式。其研究方法涉及造山带原型盆地的物源和组分分析、沉积相和沉积体系及沉积构型分析、充填序列和构造层序分析、古流向和古地理分析、沉积厚度和沉降分析以及沉积盆地动力模拟等。 相似文献
7.
周口坳陷早白垩世主要发育冲积扇相、河流相、湖泊相、扇三角洲相和三角洲相等类型，其中谭庄－沈丘凹陷沉积相带呈东西向狭长展布，是一个典型的断陷盆地．本文在讨论了湖盆的物源、古地形、古水流、水介质条件及古气候条件的基础上，提出了早白垩世时周口坳陷的沉积格局。 相似文献
8.
西藏双湖托纳木地区上侏罗统雪山组物源分析 总被引：1，自引：2，他引：1
地处羌北坳陷与中央隆起带毗连地带的托纳木地区广泛发育上侏罗统雪山组沉积,厚达1500m。本文重点研究了雪山组的地层特征、古水流特征以及砂岩碎屑组分特征,在此基础上简单分析了其沉积相特征。根据雪山组的岩性及沉积构造将雪山组划分为三段,其沉积相分别为雪山组一段为前三角洲亚相,二段为三角洲前缘亚相和三角洲平原亚相组合,三段为冲积扇相。古水流复平方向分布样式指示雪山期的物源方向主要来自西南边;砂岩碎屑组分表明雪山组的母源区岩性十分多样;三角图解定量分析显示物源区基本上属于再旋回造山带,而且以石英再旋回为主,表明其物源来自于西南部的中央隆起带。 相似文献
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Turbidite facies distribution and palaeocurrent analysis of submarine fan evolution in the Pindos foreland basin of west Peloponnesus peninsula (SW Greece) indicate that this part of the foreland was developed during Late Eocene to Early Oligocene in three linear sub‐basins (Tritea, Hrisovitsi and Finikounda). The basin fill conditions, with a multiple feeder system, which is characterized by axial transport of sediments and asymmetric stratigraphic thickness of the studied sediments, indicate that the Pindos Foreland Basin in this area was an underfilled foreland basin. Sediments are dominated by conglomerates, sandstones and mudstones. The flow types that controlled the depositional processes of the submarine fans were grain flows, debris flows and low‐ and high‐density turbidity currents. The sedimentary model that we propose for the depositional mechanisms and geometrical distribution of the turbidite units in the Tritea sub‐basin is a mixed sand‐mud submarine fan with a sequential interaction of progradation and retrogradation for the submarine fan development and shows a WNW main palaeocurrent direction. The Hrisovitsi sub‐basin turbidite system characterized by small‐scale channels was sediment starved, and the erosion during deposition was greater than the two other studied areas, indicating a more restricted basin topography with a NW main palaeocurrent direction. The Finikounda sub‐basin exhibits sand‐rich submarine fans, is characterized by the presence of distinct, small‐scale, thickening‐upward cycles and by the covering of a distal fan by a proximal fan. It was constructed under the simultaneous interaction of progradation and aggradation, where the main palaeocurrent direction was from NNW to SSE. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
11.
Palaeocurrent data from parts of the Upper Buntsandstein (Lower Triassic) of both the western (Eifel: Kyllburg-Schichten) and eastern (Bavaria: Plattensandstein) margin of the German Triassic Basin (Middle Europe) have been interpreted by circular directional statistics, eigenvalue and eigenvector analysis, autocorrelation analysis and vector trend analysis. Examination of current roses, histograms of normalized vector magnitudes and plots, of circular skewness of the distribution vs. circular kurtosis, together with the palaeocurrent plots indicate bimodal palaeocurrent distributions with bipolar orientations within long, short and very short sedimentary sequences. Subset I of the directional data is interpreted to represent larger, more continuous flows in a high-energy regime of probably perennial type, whereas subset II may represent smaller, partially episodic flows of probably ephemeral type with larger variability in direction and flow regime; transport and sedimentation rates being significantly smaller than during deposition of subset I. A part of the bimodal palaeocurrent distributions within short sedimentary sequences fits rather well into the general transport pattern. Other bipolarities are primarily interpreted as effects of superimposition of channels of different orientations as well as of main channels and crevasse-splay channels, and condensation of deposition from discontinuous or episodic flows. The main mechanism creating the vertical succession of various directions is stacking of different substratum members to multistorey complexes by primary-depositional restriction of formation and/or secondary-erosional removal of topstratum sediments. The occasional occurrence of herring-bone cross-stratification representing bipolarities within very short depositional sequences, testifies to probably episodic and random changes in water surface slopes allowing currents to reverse locally. Examination of long sedimentary sequences by autocorrelation analysis reveals changes of transport directions with time in a sinusoidal manner, indicating a conformable environmental development of the alluvial watercourses which reflects a time-cyclic trend of sedimentation by spatially continuous and time-concordant shifting of the channel system. The results of the statistical analysis enable an enhanced palaeoenvironmental reconstruction of the alluvial network which fits best to a transitional meandering-thalweg-braided channel pattern. Comparison of the statistical results, especially in the light of vector trend surface analysis, clearly reflects the different palaeogeographic positions of both investigated areas, but rules out only minor influences of regionally different palaeoslopes on the alluvial depositional environment, with the basic principles of fluvial style at the western margin (Eifel) generally matching those at the eastern margin (Bavaria) of the German Basin. 相似文献
12.
The Ringerike Group, a late Silurian fluviatile sequence in the Oslo Graben of Norway was deposited in two distinct sedimentary provinces. In the northern part of the area the Sundvollen Formation (meandering-stream sediments) and the overlying Stubdal Formation (braided) contain antiperthitic feldspars and drop perthites characteristics of the jotunites of the Jotunheim area of central Norway. Other textural, mineralogical and palaeocurrent evidence supports the conclusion that these two formations were derived from a relatively distant source area, which included the Jotunheim, part of the newly raised Caledonian orogen.To the south, the sandstones of the Holmestrand area are much coarser grained and show a distinctive mineralogy, composition and texture. This evidence, supported by palaeocurrent studies, is consistent with a proximal source area on the eastern flank of the Oslo Graben. Source rocks consisted predominantly of high-grade metamorphic and igneous rocks of the Precambrian basement and the overlying Eocambrian sedimentary rocks. 相似文献
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J. R. L. ALLEN 《Sedimentology》1966,6(3):153-190
Bed forms arise by interaction between a fluid flow and the sediment transported over or close to the bed. The geometry of bed forms is two-dimensional or three-dimensional. Two-dimensional bed forms generate two-dimensional internal sedimentary structures and are adjusted to two-dimensional flow-vector fields. Three-dimensional bed forms generate three-dimensional internal sedimentary structures and are adjusted to three-dimensional flow-vector fields. Many shallow-water flow systems observable today are each characterised by flow-vector fields of unequal rank, and hence are hierarchically structured. Hierarchies of bed forms and internal structures which parallel the hierarchies of flow-vector fields can also be established in the case of these flow systems. A single type of bed form or internal structure from an hierarchically structured flow system cannot specify that system fully with regard to either its directional or flow-dynamic characteristics. An approach to palaeocurrent analysis that is more flexible and comprehensive than previously attempted may therefore be desirable. 相似文献
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冲积沉积结构单元分析法综述 总被引：7，自引：1，他引：6
结构单元分析就是结合古流数据对露头横剖面进行岩石相、界面和结构单元的划分,以揭示沉积体系的三维展布,恢复沉积体系的演化史,它是目前研究露头沉积地质的最佳方法之一。本文对结构单元分析法的原理及其在几类沉积体系中的应用作了介绍。在此基础之上,讨论了结构单元分析法存在的几个问题以及它与层序地层学的关系。 相似文献
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关于准噶尔盆地与吐哈盆地侏罗纪的沉积边界问题，争论历时已久。总的来说，构造上分歧不大，而沉积上则各抒己见．为全面而系统地解决这些问题，更好地指导准噶尔盆地与吐哈盆地的侏罗系勘探及两个盆地的地质类比，本文通过博格达山南北缘侏罗沉积相、古流向及物源等方面的实地测量和分析，同时结合区域构造背景，对准噶尔盆地与吐哈盆地侏罗纪沉积边界作了进一步探讨，认为准噶尔盆地与吐哈盆地至少在侏罗纪沉积之前已被博格达山分隔开，从而开始了各自的沉积构造演化史。 相似文献
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在扬子地台东南的浙西、皖南地区,晚奥陶世晚期地层具有鲜明的沉积学特征。它对认识本区加里东晚期古构造环境有着十分重要的意义。关尹文(1959)、李继亮(1978)、吕洪波(1987)、余素玉(1986)先后在临安、宁国、绩溪等地对其韵律结构、沉积构造及矿物岩石学方面进行了不同程度的研究。关尹文、吕洪波称之为浅水复理石。李继亮认为是深水浊流沉积。笔者(1989)在江山一带对相应地层进行了系统的沉积相研究,结合浙、皖浊积岩系特征的对比,对浊积扇的构成及其发育的构造古地理条件进行了初步探讨。 相似文献
18.
鄂尔多斯盆地拉什仲组遗迹化石组合与古环境 总被引：4，自引：0，他引：4
首次对鄂尔多斯盆地西北缘桌子山地区中奥陶世拉什仲组的遗迹化石进行了系统研究。该组遗迹化石共有6属8种,建立了Paleodictyon遗迹化石组合。此组合以被侵蚀、改造呈斑状分布的遗迹大量存在与Paleodictyon的普遍出现为最显著的特征。遗迹化石的形态、行为习性、保存方式等分类特征、埋藏学特征等表明该组合相当于Nereites遗迹相,代表了深海远源浊流沉积环境;而在本组沉积晚期,水体开始变浅,大致为大陆斜坡－陆隆半深海浊流沉积环境。其沉积层序、沉积构造及岩性等特征说明拉什仲组为典型的浊流相沉积,并以远源相浊流沉积为主,其下部近相浊流沉积较发育。据古流向测定,自中奥陶世拉什仲组至公乌素组沉积期,重力流运动方向的变化大致反映了贺兰拗拉槽张裂的幅度在变小并渐呈收敛隆起的趋势。 相似文献
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以江苏中部海岸潮滩沉积为原型,提出了获取潮滩沉积记录中沉积层保存潜力信息的正演模拟方法。模拟结果显示,在沉积物供应恒定的条件下,随着潮滩的不断淤长,岸线淤进速率逐渐减小,潮滩滩面的沉积速率逐渐降低,而潮滩层序中的泥质沉积的厚度向海逐渐增厚。沉积层保存潜力的计算结果显示,潮滩上保存潜力在高潮位附近和潮下带的较低部位为最高,可达80 ％ 以上,潮间带下部存在着低值区,保存潜力低于20 ％ ,与前人在潮间带进行的现场观测结果相近。对研究方法经进一步细化(如考虑滩面坡度和粒度分布变化、波浪和风暴潮作用、潮沟摆动等因素),并与反演方法相结合,可望更好地解释沉积记录中的环境演化信息。 相似文献
20.
The extent of the deposition and of the preservation of the Blouberg Formation and Waterberg Group was at least partially controlled by brittle reactivation along the Palala Shear Zone. The Palala Shear Zone in the Blouberg area (Northern Province, South Africa) is characterised by granulite-grade gneiss, and formed by sinistral transpressional collision between the Southern Marginal Zone (Kaapvaal Craton) and the Central Zone of the Limpopo Belt. The Limpopo collision is thought to have occurred either at 2.0 Ga or at 2.7 Ga with reactivation at 2.0 Ga. Deposition of the Blouberg Formation was characterised by syn-sedimentary tectonism, which is reflected by a sudden upward coarsening in sedimentary rocks, and by the presence of a strongly folded and thrusted lower member. Bedding orientations and slickenside lineation orientations suggest that vergence was towards the south, and such a tectonism can be inferred to have produced a highland area to the north, bound on the southern margin by the southern strand of the Melinda Fault. The presence of an inferred northerly upland area is supported by palaeocurrent directions and the preservational extent of the Setlaole and Makgabeng Formations of the Waterberg Group (post-Blouberg Formation). The extent and stratigraphy of the overlying Mogalakwena Formation suggests that these strata onlapped northwards over the denuding highlands. Younger Sibasa basalts of the Soutpansberg Group have been dated at ca. 1.85 Ga. Blouberg and Waterberg strata can therefore be interpreted as syn- and post-tectonic sedimentary rocks, respectively, following a ca. 2.0 reactivation event along the Palala Shear Zone. It is difficult to reconcile the succession of geological events at Blouberg with a ca. 2.0 Ga Limpopo orogeny, and thus sedimentary strata in the study area support a 2.7 Ga date for Limpopo collision, with syn-Blouberg tectonism relating to ca. 2.0 reactivation within the previously assembled Limpopo Belt. 相似文献