共查询到20条相似文献，搜索用时 296 毫秒
1.
2.
鄂尔多斯盆地东北部东胜—纳林河一带出露的中生界三叠系—侏罗系—白垩系地层,为一套河湖相沉积（白垩系可能有风成沉积）。在三叠系—侏罗系地层中发育完好的风暴沉积和风暴岩。在东纳林煤矿—德胜西岔路口的109国道两侧长约40 km的三叠系—侏罗系地层中发育风暴沉积,该德胜西剖面连续长度达548 m。这套风暴沉积主要为一套河流—三角洲—湖泊沉积（有少量泥炭沼泽）,并以发育典型的风暴沉积构造:丘状构造（Hummocky Structures,HS）、洼状构造（Swaley Structures,SS）、丘状交错层理（Hummocky Cross Stratification,HCS）和洼状交错层理（Swaley Cross Stratification,SCS）极为引人注目。初步研究认为,这套风暴沉积和风暴岩主要发育在浅水湖泊中。主要特点:1）凡发育有风暴沉积或风暴岩的地方,地层的成层性极差,地层多呈透镜状、豆荚状或波浪状;2）岩层的接触关系主要为冲刷面,很少正常沉积接触,冲刷面呈不规则波浪状,最大起伏可达2 m;3）丘状和洼状构造具有连续的正弦曲线的完美形态,规模在中大型,波长在数米到近百米,高数十厘米到1~2 m;4）岩性及其组合主要为一套黄褐色砾岩+砂岩+灰色泥岩;具有明显的二元结构（下粗上细;下部块状上部发育层理）;在以粗碎屑为主的风暴沉积中砾岩是常见的底部沉积。在纳林煤矿附近有煤层形成的风暴沉积和风暴岩;5）在德胜西岔路口的重要剖面的风暴沉积和风暴岩底部发育了1~3层较厚的砾石层,其中中间一层为厚数十厘米到1~2 m,砾石直径大者可达30~40 cm,大部分具有叠瓦构造,前者可能指示了向湖的风暴回流,后者指示了向岸的冲洗流,揭示了风暴冲洗流非常强劲;6）灰色含砾块状泥岩,砾石呈漂浮状,揭示含砾泥岩是风暴冲洗流形成的类似于泥石流的快速沉积,而非正常天气形成的静水沉积;厚数十厘米的含砾泥岩揭示了当时的沉积速率相当大,也揭示了风暴流极其浑浊,可能几乎接近饱和;7）振荡流占优势,但在某些部位又具有明显的复合流和振荡流特点。8）总体沉积背景是一种宽阔浅水湖泊环境,以原地振荡垂向沉积为主。鄂尔多斯盆地三叠系—侏罗系湖泊风暴沉积是一种新的沉积类型。到目前为止,还未见到有关如此大型的HCS和SCS的相关报道。研究表明,形成这种风暴沉积的水体的最大深度在50 m左右。鄂尔多斯盆地早三叠世—中侏罗世的风暴沉积和风暴岩的长期发育与长期稳定的强烈亚洲季风有关。 相似文献
3.
4.
何玉平 《吉林大学学报(地球科学版)》2020,50(2):500-508
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
5.
作者对浙西寒武系碳酸盐岩做系统调查时发现,在开化裴岭脚产出的大陈岭组碳酸盐岩中含有大量的液化泥晶脉、微同生变形构造、角砾岩及与之伴生的浊积岩等典型的地震-海啸沉积标志。根据震积岩特征及其在剖面上的分布,该地大陈岭期的地震活动可以分为两期:第一期以震积岩(A,液化亮晶脉和泥晶脉)、啸积岩(B,具丘状层理或平行层理的内碎屑白云质灰岩)、震浊积岩(C,具递变层理或鲍马序列且层面上有槽模构造的砾屑白云质灰岩或砂屑白云质灰岩)和背景沉积(D)组成的A-B-C-D沉积序列为特征;第二期为震积岩(A,液化亮晶脉和泥晶脉、震裂岩、震褶岩和内碎屑角砾岩等)和沉积背景(D)组成的A-D沉积序列。而在常山白石和芳村的大陈岭组剖面,上述特征不明显,但局部能看到液化变形构造。往南东至江山的碓边则不见震积岩特征。从震积岩的分布上分析,浙西大陈岭期的地震活动不受控于江绍深断裂,应与开化—淳安大断裂的形成有关,是开化—淳安大断裂形成于早古生代的一个证据。此外,值得一提的是,这是确凿的后震旦纪的“Molartooth”。 相似文献
6.
王承书 《沉积与特提斯地质》1995,(3):62-70
国外沉积学期刊文献摘要选登王承书编译（成都地质矿产研究所）《沉积学》４０卷第２期１９９３年４月１砾屑岩计数碎屑统计法：以美国加利福尼亚南部上第三系为例进行评论１５７砾屑沉积岩中不同岩类砾石级颗粒的相对比例在野外一般用碎屑计数来确定。碎屑计数通常用以定... 相似文献
7.
8.
甘肃岷县－宕昌地区属酉秦岭的中秦岭分区南带。下二叠统的硅质岩主要有：砾屑硅质岩、砂屑硅质岩、放射虫硅质岩和条带状硅质岩。本文主要讨论了碎屑硅质岩的沉积特征、岩石特征、沉积构造、颗粒大小、地球化学特征及沉积序列特征．从而论证了该地区的粗碎屑沉积是拉张环境深海盆地中的内源碎屑硅质浊积。通过与Ｓｔｏｗ等硅质浊积模式和经典的陆源碎屑浊积模式的对比，讨论了它的新特点，并由此进一步建立了一个深海硅质法积岩的完整沉积序列。粗碎屑硅质岩在国内外的报道还不多见，它的发现对丰富深海沉积类型及了解西秦岭的古海洋演化具有重要意义。 相似文献
9.
塔里木盆地西北缘震旦纪风暴岩成因探讨 总被引：3，自引：1，他引：2
本文首次论证了塔里木盆地西北缘震旦纪风暴岩的存在。就风暴岩的结构特征、沉积序列、成因模式作了探讨。震旦纪风暴岩具有底面侵蚀-充填构造、无规则排列的砾屑灰岩层、粒序层及丘状层理,以及水平纹理和纹状交错层。风暴岩可分为二种类型:钙屑风暴岩为强的风暴产生的风暴浪和风暴流而形成,由-套砾屑灰岩及泥灰岩、泥岩组成;砂屑风暴岩是由强度相对较弱的风暴离岸回流将风暴高峰悬浮起的砂屑物带到浪基面以下的地方沉积而成,由砂岩、粉砂岩及粉砂质泥岩组成。 相似文献
10.
论震积作用和震积岩 总被引：93，自引：2，他引：93
地震是一种灾害性的地质事件。地震及其引发的海啸、重力流可以形成震积岩、海啸岩和震浊积岩。在地震过程中,震积作用可以形成特殊的构造标志(地震断裂层、地裂缝、微同沉积断裂、微褶皱纹理、重力断层等)、沉积和成岩标志(砂岩脉、泥岩脉、泥晶脉,即磨牙(molar tooth)构造、枕状层、砂火山、泥火山、同沉积变形构造、丘状层理等)。地震沉积组合包括原地震积岩(A,包括震裂岩、震褶岩、自碎屑角砾岩、内碎屑副角砾岩等)、海啸岩(B,由具丘状层理、平行层理的碎屑岩或内碎屑灰岩组成)、震浊积岩(C,由具块状层理、递变层理或玻马序列的粗碎屑岩或碎屑灰岩组成)及背景沉积(D)4个单元,它们组合成A-B-C-D、A-B-D、A-C-D、A-D、B-D、C-D等6种类型的沉积序列。 相似文献
11.
Zaytsev A. I. Pelinovsky E. N. Yalciiner A. Susmoro H. Prasetya G. Hidayat R. Dolgikh G. I. Dolgikh S. G. Kurkin A. A. Dogan G. Zahibo N. Pronin P. I. 《Doklady Earth Sciences》2019,486(1):588-592
Doklady Earth Sciences - Numerical simulation of a tsunami from September 28, 2018, on Sulawesi Island (Indonesia) is carried out. It is shown that the observed distribution of tsunami heights... 相似文献
12.
Doklady Earth Sciences - The problem of tsunami warning and the use of the grid-characteristic method developed for studying wave processes in heterogeneous media is addressed. A multilayer... 相似文献
13.
试用地球系统科学观解读2004年印度洋地震海啸 总被引：3，自引：0，他引：3
2004年印度洋地震海啸是本世纪初全球发生的最为惨重的自然灾害.这次地震海啸涉及地球的岩石圈、水圈、大气圈和生物圈,甚至还有地外星球和月球的作用,造成能量与物质之间的相互转化与传递,说明地球是一个完整的统一整体.因此,对地震海啸等自然灾害必须采用地球系统科学观进行分析和研究,找出彼此之间的相互关系、形成机制和演化规律,并用信息化、全球化和可持续发展的地球科学观来研究和防御地震海啸. 相似文献
14.
Shokin Yu. I. Gusiakov V. K. Kikhtenko V. A. Chubarov L. B. 《Doklady Earth Sciences》2019,489(2):1444-1448
Doklady Earth Sciences - Overview maps of tsunami hazards for the Far Eastern coast of the Russian Federation are created. The methodological principles of the PTHA (Probabilistic Tsunami Hazard... 相似文献
15.
Doklady Earth Sciences - The features of vortical suppression of tsunami waves by an impermeable underwater barrier have been studied. The height of the barrier is close to the optimum... 相似文献
16.
Validating a Tsunami Vulnerability Assessment Model (the PTVA Model) Using Field Data from the 2004 Indian Ocean Tsunami 总被引：2，自引：1，他引：2
The “PTVAM” tsunami vulnerability assessment model [Papathoma and Dominey-Howes: 2003, Nat. Hazards Earth Syst. Sci. 3, 733–744; Papathoma et al.: 2003, Nat. Hazards Earth Syst. Sci. 3, 377–389], like all models, requires validation. We use the results from post-tsunami surveys in the Maldives following the
December 26, 2004 Indian Ocean tsunami to ‘evaluate’ the appropriateness of the PTVAM attributes to understanding spatial
and temporal vulnerability to tsunami damage and loss. We find that some of the PTVAM attributes are significantly important
and others moderately important to understanding and assessing vulnerability. Some attributes require further investigation.
Based upon the ground-truth data, we make several modifications to the model framework and propose a revised version of the
PTVAM (PTVAM 2). 相似文献
17.
Subduction zones are one of the most critical types of plate boundary of the Earth system, crucial for the global geochemical recycling of the Earth system, genesis of island arc and continental crust, and mechanisms of earthquake and tsunami processes. Ocean drilling plays an essential role in advancing our understanding of the subduction processes. This paper highlights the recent progress and scientific goals of the international ocean drilling programs in subduction systems and discusses implications for strategic planning of the future ocean drilling initiatives. 相似文献
18.
In this article, we assess the human and economic hazard posed by tsunami waves generated from impacts of sub-2 km diameter
asteroids. Annually, on average, 182(+197/−123) people will be affected by impact-induced waves with a corresponding infrastructure
loss of $18(+20/−12)M/y. Half of the tsunami hazard stems from impactors with diameters less than 300 m. One near Earth asteroid
will survive atmospheric transit and strike somewhere into Earth’s oceans every 5880 years, on average. In the mean generic
scenario, the tsunami from the impact affects 1.1 million people and destroys $110B of infrastructure. 相似文献
19.
Use of tsunami waveforms for earthquake source study 总被引：1，自引：0，他引：1
Tsunami waveforms recorded on tide gauges, like seismic waves recorded on seismograms, can be used to study earthquake source processes. The tsunami propagation can be accurately evaluated, since bathymetry is much better known than seismic velocity structure in the Earth. Using waveform inversion techniques, we can estimate the spatial distribution of coseismic slip on the fault plane from tsunami waveforms. This method has been applied to several earthquakes around Japan. Two recent earthquakes, the 1968 Tokachi-oki and 1983 Japan Sea earthquakes, are examined for calibration purposes. Both events show nonuniform slip distributions very similar to those obtained from seismic wave analyses. The use of tsunami waveforms is more useful for the study of unusual or old earthquakes. The 1984 Torishima earthquake caused unusually large tsunamis for its earthquake size. Waveform modeling of this event shows that part of the abnormal size of this tsunami is due to the propagation effect along the shallow ridge system. For old earthquakes, many tide gauge records exist with quality comparable to modern records, while there are only a few good quality seismic records. The 1944 Tonankai and 1946 Nankaido earthquakes are examined as examples of old events, and slip distributions are obtained. Such estimates are possible only using tsunami records. Since tide-gauge records are available as far back as the 1850s, use of them will provide unique and important information on long-term global seismicity. 相似文献
20.
This paper presents a simple model for tsunami sedimentation that can be applied to calculate tsunami flow speed from the thickness and grain size of a tsunami deposit (the inverse problem). For sandy tsunami deposits where grain size and thickness vary gradually in the direction of transport, tsunami sediment transport is modeled as a steady, spatially uniform process. The amount of sediment in suspension is assumed to be in equilibrium with the steady portion of the long period, slowing varying uprush portion of the tsunami. Spatial flow deceleration is assumed to be small and not to contribute significantly to the tsunami deposit. Tsunami deposits are formed from sediment settling from the water column when flow speeds on land go to zero everywhere at the time of maximum tsunami inundation. There is little erosion of the deposit by return flow because it is a slow flow and is concentrated in topographic lows. Variations in grain size of the deposit are found to have more effect on calculated tsunami flow speed than deposit thickness. The model is tested using field data collected at Arop, Papua New Guinea soon after the 1998 tsunami. Speed estimates of 14 m/s at 200 m inland from the shoreline compare favorably with those from a 1-D inundation model and from application of Bernoulli's principle to water levels on buildings left standing after the tsunami. As evidence that the model is applicable to some sandy tsunami deposits, the model reproduces the observed normal grading and vertical variation in sorting and skewness of a deposit formed by the 1998 tsunami. 相似文献