共查询到20条相似文献，搜索用时 105 毫秒
1.
中国西南山区的泥石流防治及展望 总被引：2，自引：0，他引：2
唐晓春 《海洋地质与第四纪地质》1995,15(3):105-112
本文在前人相关研究的基础上，结合作者的研究工作，对以川西山地和滇北山地为主体的中国西南山区泥石流及其防治进行了综述。以城镇泥石流、铁路泥石流和公路泥石流防治为重点，分析了中国西南山区泥石流防治的原则、方案、措施和防治效益评估等方面的研究进展及存在的问题。以泥石流防治工程的规范化、标准化，泥石流防治工作的系统化和最优化以及泥石流紧急避难体制等方面展望了中国西南山区未来的泥石流防治工作。 相似文献
2.
辽东山区泥石流成因和危险度区划研究 总被引：5，自引：0，他引：5
本文从辽东山区的自然条件和人类经济活动入手，分析了山地泥石流的形成原因、特征和性质，认为本区为暴雨型泥石流，特大暴雨是触发泥石流的主导因素。地质构造、岩性、地貌等是导致泥石流的次要因素。以岫岩县为例，通过对泥石流各影响因子的综合评判，首次划分出岫岩县泥石流灾害四个级别的危险度分区，为泥石流的综合防治提供了科学依据。 相似文献
3.
David Casas Gemma Ercilla Adolfo Maestro Ferran Estrada Marga Garcia Javier Hemandez 杨丽娟 《海洋地质》2009,(1)
Gebra谷位于中Bransfield盆地的斜坡上，该盆地是一个年轻的、断裂活动强烈的南极洲半岛内的裂谷盆地。盆地后期发生了一系列大规模的滑坡，现在的Gebra谷是所谓“Gebra—Magia滑坡复合体”的一部分。滑坡复合体构成了块体坡移的主体部分，包括两个大型泥石流谷。本文的研究结果是根据多波束测深，高一极高频地震剖面资料得出的。通过对地貌沉积特征以及地震层序分析，对Gebra泥石流谷的沉积演化史作了新的解释。 相似文献
4.
绒扇藻属(Avrainvillea)藻体广泛分布于热带、亚热带海洋，尤其盛产于珊瑚礁上。因此，该属种类的分布在很大程度上受海区的限制。绒扇藻属的主要特征是藻体深绿色，褐绿色或黑褐色，基部是由假根状丝体相互交织，构成固着器，固着在礁石上。叶柄单生或具有多次分裂。叶片单个或多个，形状不一，多数为扇形，长圆形，肾形到扁压。藻体不钙化，通常黄色或褐色。二叉状分枝，基部常常缢缩，似念珠状或念珠状。皮层丝体无明显分化或具假皮层。关于绒扇藻属海藻的分类研究，至今为止，已发现23个种。
关于中国绒扇藻属的研究，最早是C.K.Tseng(曾呈奎)于1938年在“海南岛海产绿藻研究Ⅱ”中首次报道了两种绒扇藻，即直立绒扇藻Avrainvillea erecta (Berkeley) A. Gepp et E.S.Gepp和裂片绒扇藻A.lacerata J. Agardh，而后在1983年，在曾呈奎主编的《Common Seaweeds of China》一书中，报道了上述种类，并将其产地扩大到西沙群岛。1991年，陆保仁等在“南沙群岛海区的褐藻和绿藻研究I”中，第三次报道了裂片绒扇藻，将其产地扩大到南沙群岛。最近，作者在研究中国绒扇藻属的标本时，除了己经报道的两种外，又发现该属的1个新种(西沙绒扇藻Avrainvillea xishaensis Tseng， Dong et Lu sp. nov.)和3个新记录[模糊绒扇藻A.obscura (C.Agardh)J. Agardh，和氏绒扇藻A.hollenbergii Trono，群栖绒扇藻A.amadelpha (Montagne)A. Gepp et E.S. Gepp。至今共发现了6个种，其标本均存放在中国科学院海洋研究所植物标本室。 相似文献
5.
中国地质灾害危险性分析与灾变区划 总被引：23，自引：0，他引：23
根据中国崩塌－滑坡、泥石流、岩溶塌陷活动程度和形成条件，建立区域地质灾害危险性分析模型；据此，以县（市、区、旗）为单元，逐个计算地质灾害综合危险性指数，分析中国地质灾害危险性分布特征；结合区域地质自然条件，将中国大陆划分为七大地质灾害灾变区和若干亚区，论述了各区地质灾害危险水平和主要活动特性。 相似文献
6.
在岩心观察的基础上，利用临南洼陷主要取心井段的粒度资料，对临南洼陷下第三系碎屑岩主要沉积环境的粒度概率曲线进行了研究。结果表明：该地区主要发育的沉积相有三角洲相、扇三角洲相、洪积扇相及湖泊相，每种沉积相又分为几种沉积亚相类型；研究区下第三系碎屑岩粒度累积曲线特征主要包括：“上拱弧形”式、两段式、三段式、多段式、复杂两段式和三段式、“低斜两段”式、“一跳一悬夹过渡”式、“高斜多跳一悬”式，每种沉积亚相类型对应其独特的粒度概率累积曲线特征。 相似文献
7.
20世纪50~80年代以中国科学院海洋研究所为主，曾对海南岛进行了数次生物调查，包括：全国海洋综合调查(1958~1960年)，南海中部、东北部综合调查(1974~1985年)，全国海岛资源综合调查(1989~1993年)，中德海南岛生物联合考察(1990，1992年)及中日海南岛浅海动物多样性联合考察(1997年)等，获得了大批珍贵的海洋生物标本，这些标本基本上保存在中国科学院海洋研究所标本馆内。本文作者(Yu et al，2001)经对其中的甲壳动物等足类的整理，已记述了扇肢亚目浪飘水虱科和团水虱科的10个种。本文补充记述该亚目的4科13种，其中4种为中国海域新记录种。迄今为止，海南岛共发现扇肢亚目等足类23种，名录如下(其中*为本次补充种；**为中国海域新记录种)。 相似文献
8.
岬间海湾平面平衡形态规律的研究是砂质海岸稳定与演变研究的重要内容。简要回顾了岬间海湾平面形态规律的研究进展,着重介绍了海湾平衡形态的五个模型。通过评述平衡形态模型的优缺点,指出机理分析和经验拟合相结合应该为以后海湾平面平衡形态规律的研究发展方向,并论述了我国岬间砂质海湾平面平衡形态研究的重要意义。 相似文献
9.
科尔占地区位于滨里海盆地阿斯特拉罕-阿克纠宾斯克隆起带东南部的比伊克扎尔次级隆起上，该地区广泛发育下二叠统孔谷组盐岩，以盐岩沉积为界，它将整个剖面划分为盐上层系（以碎屑岩为主的含油气层系）和盐下层系（以碳酸盐岩为主的含油气层系）两个大的含油气层系，石炭系为盐下层系中主要的含油气层系之一。通过对研究区唯一的盐下井K井岩屑及其薄片的详细观察，并结合该井测井资料，分析了石炭系的沉积特征，并对其沉积相进行了划分与描述。K井石炭系主要发育3种类型沉积相，分别为深水浊积扇相、斜坡相和台地相，其中深水浊积扇相可进一步划分为内扇、中扇和外扇3个亚相，台地相划分为滩间洼地和台内滩2个亚相。利用K井钻探结果，结合区域资料，初步预测出科尔占地区早石炭世和中石炭世末期沉积相带的平面分布特征。 相似文献
10.
岬间海湾平面平衡形态规律的研究是砂质海岸稳定与演变研究的重要内容.简要回顾了岬间海湾平面形态规律的研究进展,着重介绍了研究海湾平衡形态的五个模型.通过评述平衡形态模型的优缺点,指出机理分析和经验拟合相结合应该为以后海湾平面平衡形态规律的研究发展方向,并论述了我国岬间砂质海湾平面平衡形态研究的重要意义. 相似文献
11.
Franco Ricci Lucchi 《Geo-Marine Letters》1984,3(2-4):203-210
Submarine fans of different sizes, geometry, and petrology were built in the Marnoso-arenacea Basin, a migrating foredeep
within an active continental margin. In an initial depositional stage, a well-developed basin plain received sediment from
flows that by-passed restricted fan systems, now buried, located near the north end of an elongated basin. Minor fans grew
near the steeper, tectonically deformed side of the basin. In the later stage, turbidite deposition was stopped in the former
basin plain. Sediment sources and feeder channels shifted and fed fan lobes that prograded in a narrower trough and were distored
(choked). The tectonic control on development of megasequence and sand bodies is stressed here in contrast with previous emphasis
on “inner” or “autocyclic” mechanisms.
Margin setting represents fan and/or source area 相似文献
12.
Drilling has shown that there is a large petroleum reserve in the Liushagang Formation of the Fushan Depression, South China Sea from reservoirs of the sublacustrine fans. To reduce the risk associated with exploration, the sedimentary characteristics of the sublacustrine fans should be identified and described. Analysis of the drilling cores, well data and 3D seismic data was conducted to identify and interpret the sublacustrine fans which formed in a lacustrine succession as the low-stand fan of the 2nd member of Liushagang Formation (SQEls2). The reservoirs were commonly associated with pebbly conglomerates, mudstone shivers, muddy debris, various deformation structures including micro-faults, liquified deformation structure, ball and pillow structure, slump and stress-release deformation. Further contrastive analysis of sedimentary characteristics and palaeogeomorphology between the western and eastern sublacustrine fans indicates that they belong to two different types of sublacustrine system in continental basins. More specifically, the western fan, controlled by the multi-level step-fault belt, is a typical gravel-rich sublacustrine system which is characterised by structurally controlled, high gradient (2.8–3.3°), admixtures of muddy debris and pebbly conglomerates and poor reservoir quality, while the eastern fan, controlled by the flexure slope-break belt, is a sand-rich sublacustrine system dominated by relatively low gradient (2.0–2.5°), general fining-upwards trend with good reservoir quality. Therefore, the development of future exploration should be conducted at different levels in the Fushan Depression. 相似文献
13.
海盆沉积“源-汇”系统分析:南海北部珠江海谷-西北次海盆第四纪深水浊积扇 总被引：2，自引：0，他引：2
运用近年来采集的高分辨率地震资料和多波束测深数据,在珠江海谷及西北次海盆深海平原区发现大规模发育的第四纪重力流沉积体系,该沉积体系沿珠江海谷以北西-南南东方向贯穿整个北部陆坡,进入西北次海盆后呈扇形展开,形成珠江海谷-西北次海盆大型深水浊积扇系统。据沉积体系空间展布特征差异,将珠江海谷划分为北、中、南三段,北段为过路侵蚀和水道下切,中段以水道充填和天然堤沉积为主,南段以水道-天然堤和朵叶体沉积共存为特征,揭示出北部陆坡珠江海谷是珠江口外陆缘物质输送海盆深海平原的主要通道;海盆区总体以朵叶体发育为特色,呈扇形展布。深水扇系统可分为三期次沉积体,其区域结构记录了重力流沉积物从侵蚀、卸载到南海海盆作为限制性盆地接收陆源沉积物的全过程,为“源-渠-汇”的研究构建了一个完美的范例。本文以珠江海谷-西北次海盆第四纪深水浊积扇沉积体系为例,完整地揭示了水道-扇体的组构和特征,清晰呈现了陆坡-海盆砂体展布的规律,可为建立南海北部新近纪早期深水扇形成模式提供参考,有助于指导南海深水油气勘探工作。 相似文献
14.
The synsedimentary faults and basin-marginal fans located in the central part of the deep-water area of the early Oligocene Qiongdongnan Basin have been investigated using seismic profiles, boreholes, and well-log data.Through the formations of the characterized paleogeomorphology, such as transverse anticlines, fault ditches,and step-fault belts, the synsedimentary faults are known to have controlled the development position,distribution direction, and extension scales of the basin-marginal fans. For example, at the pitching ends of two adjacent faults, transverse anticlines developed, which controlled the development positions and distributions of the fans. During the early Oligocene, the faults controlled the subsidence center, and fault ditches were formed at the roots of the faults. In the surrounding salient or low salient areas, which were exposed as provenance areas during early Oligocene, the fault ditches acted as the source channels and determined the flow paths of the clastics, where incised valley fills were obviously developed. The fault ditches which developed in the sedimentary basins were able to capture the drainage systems and influenced the distributions of the fans. The large boundary faults and the secondary faults generated two fault terraces and formed step-fault belts. The first fault terrace caused the clastics to be unloaded. As a result, fans were formed at the entrance to the basin. Then, the second fault terrace caused the fans to move forward, with the fans developing in a larger extension scale. The results obtained in this study will potentially be beneficial in the future prospecting activities for reservoirs and coalmeasure source rocks in the basins located in the deep-water areas of the South China Sea. 相似文献
15.
K. T. Pickering 《Geo-Marine Letters》1982,2(1-2):41-46
Deep-water siliciclastic systems are classified primarily on their shape as: submarine fans with well developed or poorly
developed morphology, slope drapes, for example, over relatively stable basin margins, fault-scarp aprons, canyons and large
channels, under-supplied sheet systems such as abyssal plains, non-fan ponded systems such as over-supplied perched basins,
and fan deltas. Collectively, or separately, these systems may form sedimentary basin fills that can be over or under-supplied
with respect to the sediment input although most systems will tend toward over-supply/overflow with time. Finally, the sum
total of the siliciclastic systems and basins can be used to define the tectonic milieux such as passive, strike-slip and
convergent margins. 相似文献
16.
The Upper Cretaceous and Paleocene Gottero Sandstone was deposited as a small deep-sea fan on ophiolitic crust in a trench-slope
basin. It was thrust northeastward as an allochthonous sheet in Early and Middle Cenozoic time. The Gottero, as thick as 1500
m, was probably derived from erosion of Hercynian granites and associated metamorphic rocks in northern Corsica. Outcrops
of inner-fan channel, middle-fan channel and interchannel, outer-fan lobe, fan-fringe, and basin-plain facies associations
indicate that the depositional model of Mutti and Ricci Lucchi for mixed-sediment deep-sea fans can be used. The original
fan had a radius of 30 to 50 km.
Margin setting represents fan and/or source area 相似文献
17.
18.
Franco Ricci Lucchi 《Geo-Marine Letters》1983,3(2-4):203-210
Submarine fans of different sizes, geometry, and petrology were built in the Marnoso-arenacea Basin, a migrating foredeep within an active continental margin. In an initial depositional stage, a well-developed basin plain received sediment from flows that by-passed restricted fan systems, now buried, located near the north end of an elongated basin. Minor fans grew near the steeper, tectonically deformed side of the basin. In the later stage, turbidite deposition was stopped in the former basin plain. Sediment sources and feeder channels shifted and fed fan lobes that prograded in a narrower trough and were distored (choked). The tectonic control on development of megasequence and sand bodies is stressed here in contrast with previous emphasis on “inner” or “autocyclic” mechanisms. 相似文献
19.
琼东南盆地中央峡谷的形态及成因 总被引：11，自引：0，他引：11
琼东南盆地中央峡谷平面上呈"S"型、NE向展布,西起莺歌海盆地中央凹陷带,经乐东凹陷、陵水凹陷、松南凹陷、宝岛凹陷、长昌凹陷,向东延伸进入西沙海槽。剖面形态上存在"V"型、"W"型、"U"型和复合型等4种类型。通过不同区域峡谷下切底界面的形态变化及充填特征,将中央峡谷划分为东段、西段和转换段3个区段,转换段与琼东南盆地的构造转换段相一致,即以西地区控凹断裂为NE向,而以东地区控凹断裂渐变为NEE或EW向。琼东南盆地中央峡谷的成因与构造作用和深水沉积作用关系密切,峡谷东段主要受构造作用控制,特别是深部隆起的存在为黄流期中央峡谷的形成提供了"限制性"作用,并且为后期中央峡谷的发育提供了"限制性通道";西段则受深水沉积作用的控制,重力流沉积为中央峡谷的下切和充填提供了来源。每期中央峡谷的形成均稍早于或与该时期陆坡的发育同期,最早形成于盆地东部,并随陆坡的持续向西迁移表现为不断向西上溯,下切能力逐渐减弱。 相似文献
20.
在国家重点基础研究发展规划的支持下,2000年8月在南海组织了1次多船同步海洋学调查,是迄今为止盛夏期间唯一一次全海盆准同步水文观测。航次间遭遇的多种困难虽被及时化解,然而观测数据的质量已受影响。此前虽已有若干相关研究发表,但未见对观测数据进行质量控制和全面的分析。本文在对CTD和ADCP原始数据仔细校正的基础上,分析和讨论了盛夏期间南海海盆的水文和环流特征,冀留下尽可能完整的记录。分析表明,盛夏期间以海盆SW?NE向轴线为界,南海展现出不同的物理特征。轴线东南受季节性反气旋环流控制,其中次海盆尺度的南沙反气旋环流尤其强大;轴线西北则受各种中尺度现象支配,未见明显的大尺度环流结构。研究证实南沙反气旋环流的水平尺度超过400 km,垂直尺度达近千米,最大流速近1 m/s, 是夏季南海最突出的环流特征,但发现其位置和强度存在显著的年际变化。研究并发现,不同于以往的认识,观测期间民都洛海峡交换呈“三明治”结构,表明随强迫条件变化,民都洛海峡交换可出现不同模态。 相似文献