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1.
长江三角洲北翼全新统底界和“硬粘土层”的讨论   总被引:21,自引:0,他引:21  
本文以钻孔资料为依据,通过岩石地层学、生物地层学和~(14)C测年分析,认为应以第一海相层底板作为Q_4/Q_(1-3)界线,而不能机械地划在“硬粘土层”顶板;上更新统顶部属河漫、湖沼相沉积,后经暴露、脱水局部层段硬化而成为所谓的杂色“硬粘土层”;本区晚更新世末古地形呈由东、东南向西、西北逐渐抬升的掀斜状,并控制着全新世的海侵方向和范围。  相似文献   

2.
黄河三角洲潮滩发育时空谱系   总被引:3,自引:0,他引:3  
研究黄河三角洲潮滩发育的时空话系指出:在时间上,黄河三角洲潮滩系由不同时期河口滩发育而成,各段潮滩发育时间因素的差异在比较形态学上有清晰反映,在空间上,并存着处于不同发育阶段上的四种类型(阶段)。由此构成了黄河三角洲前沿所特有的湖滩形态时空体系。  相似文献   

3.
通过对黄骅地区的实地调查,根据钻孔的分析对比,对黄骅地区全新世以来古黄河三角洲的特点、分布及其演化有了更进一步的认识。从沉积物的矿物成分,粒度变化、垂向结构等方面与现代黄河三角洲对比研究,证明黄骅地区全新世以来确实存在古黄河三角洲,其各方面特征与现代黄河三角洲相近或相同。只是因多期迭覆,后期改造,使之成为一个不十完整的、复杂的古黄河三角洲的复合体。  相似文献   

4.
Organic contaminant and total mercury concentrations were compared in four species of lamniform sharks over several age classes to examine bioaccumulation patterns and gain insights into trophic ecology. Contaminants found in young of the year (YOY) sharks were assumed to be derived from maternal sources and used as a proxy to investigate factors that influence maternal offloading processes. YOY white (Carcharodon carcharias) and mako (Isurus oxyrinchus) sharks had comparable and significantly higher concentrations of PCBs, DDTs, pesticides, and mercury than YOY thresher (Alopias vulpinus) or salmon (Lamna ditropis) sharks. A significant positive relationship was found between YOY contaminant loads and maternal trophic position, suggesting that trophic ecology is one factor that plays an important role in maternal offloading. Differences in organic contaminant signatures and contaminant concentration magnitudes among species corroborated what is known about species habitat use and may be used to provide insights into the feeding ecology of these animals.  相似文献   

5.
浅表土体强度对黄河水下三角洲微地貌形成的控制作用   总被引:6,自引:0,他引:6  
通过在黄河三角洲潮滩现场进行土体强度试验研究,发现黄河三角洲沉积土体强度浅表存在空间非均匀性,指出浅表土体强度的非均匀性是控制黄河水下三角洲微地貌形态复杂性的基础。  相似文献   

6.
Transition to low carbon sea transport is a logical response to the extreme dependency of the Pacific Islands region on imported fossil fuel, its significant vulnerability to the effects of climate change and the critical shipping needs of Pacific Island countries (PICs). Building on previous work in low carbon sea transport in the Pacific, this paper further considers the barriers to achieving such transition by assessing, through a ‘post-Paris Agreement’ lens, the Intended Nationally Determined Contributions (INDCs) submitted by PICs and contrasting these to the near total lack of investment and planning for low carbon transition in the transport sector with the parallel occurrence in the electricity sector where ~USD 2 billion of donor investment is deployed or queued despite electricity using only ~20% of fossil fuel across the region. Consistent with recent international studies, inadequate and inappropriate financing and policy have been identified as dominant transition barriers for low carbon sea transport development in PICs. This paper further examines the regional level barriers to policy development, and finds them inhibited by the silo nature of the major regional actors. The implications that the Paris Agreement has for climate financing to support the essential research and capacity development needed to underpin a successful low carbon sea transport transition strategy at any useful scale and speed are also considered in this paper.  相似文献   

7.
作者提出玉米在有节奏生长全过程中的“双S”动态模型。第一个“S”过程是从出苗到开花授粉阶段,这一过程主要是根、茎、叶以及花器的建成。第二个“S”过程是从开花授粉到籽粒成熟阶段,这一过程光合产物的积累主要用于籽粒的增重。作者认为:“双S”生长模型揭示了玉米生长的内在规律,有助于玉米栽培管理科学化。  相似文献   

8.
珠江三角洲河道近期冲淤特征初步分析   总被引:1,自引:0,他引:1  
黄镇国  张伟强 《台湾海峡》2005,24(4):417-425
近20多年,在人为因素影响下,珠江三角洲网河区和口门区的水沙分配发生了 重大变化.水沙东输,加速了伶仃洋的淤积,其年均淤积量、水域缩减面积、滩涂的年 均增长率,分别为磨刀门的2.4倍、1.7倍、6.4倍.网河区河道由淤转冲,过水断面面 积扩大13.9%~31.9%;冲刷速率12~21cm/a.  相似文献   

9.
Caprock has the most important role in the long term safety of formation gas storage. The caprocks trap fluid accumulated beneath, contribute to lateral migration of this fluid and impede its upward migration. The rapid upward passage of invasive plumes due to buoyancy pressure is prevented by capillary pressure within these seal rocks. In the present study, two main seal rocks, from the Zagros basin in the southwest of Iran, a shale core sample of Asmari formation and an anhydrite core sample of Gachsaran formation, were provided. Absolute permeabilities of shale and anhydrite cores, considering the Klinkenberg effect, were measured as 6.09 × 10−18 and 0.89 × 10−18 m2, respectively. Capillary sealing efficiency of the cores was investigated using gas breakthrough experiments. To do so, two distinct techniques including step by step and residual capillary pressure approaches were performed, using carbon dioxide, nitrogen and methane gases at temperatures of 70 and 90 °C, under confining pressures in the range 24.13–37.92 MPa. In the first technique, it was found that capillary breakthrough pressure of the cores varies in the range from 2.76 to 34.34 MPa. Moreover, the measurements indicated that after capillary breakthrough, gas effective permeabilities lie in range 1.85 × 10−21 – 1.66 × 10−19 m2. In the second technique, the minimum capillary displacement pressure of shale varied from 0.66 to 1.45 MPa with the maximum effective permeability around 7.76 × 10−21 – 6.69 × 10−20 m2. The results indicate that anhydrite caprock of the Gachsaran formation provides proper capillary sealing efficacy, suitable for long term storage of the injected CO2 plumes, due to its higher capillary breakthrough pressure and lower gas effective permeability.  相似文献   

10.
本文在综合我所多年实地观测资料的基础上,讨论了黄河三角洲胜利油田所辖部分岸段岸滩演化和防护问题。认为岸滩演化主要受制于黄河尾闾变化和海动力的相互作用,预测了1996年汛期到来前黄河入海口由北汊1南侧人工改道后,岸滩发育的基本趋势和需要重视的问题。文章也讨论了防潮堤和有关海上设施的防护问题。  相似文献   

11.
珠江河口特征认知的发展   总被引:3,自引:3,他引:0  
赵焕庭 《海洋学报》2018,40(7):1-21
人们对珠江河口的认知发生过几次飞跃。第一次认知飞跃,柯维廉(W.Olivecrona)1915年首次提出了珠江三角洲的概念;第二次认知飞跃,吴尚时1937年证明海水曾深入广州形成珠江河口湾并发育三角洲,1941和1947年先后著文肯定了珠江三角洲的存在,并确定了其主体范围;第三次认知飞跃,曾昭璇1980年提出了冲缺三角洲的概念,1997年提出了串珠状冲缺三角洲发育模式,揭示了珠江三角洲发展的时间与空间位置;第四次认知飞跃,赵焕庭1982年揭示了珠江三角洲叠置晚更新世晚期老三角洲与全新世中期现代三角洲,新资料显示还存在晚更新世中期三角洲;第五次认知飞跃,赵焕庭等于1973-1982年间运用西蒙斯优势流概念和河口盐水楔理论研究了口门和河口湾滩槽地形的发育演变;第六次认知飞跃,吴超羽等于2006年创造性应用自己研发的长周期机理模型和沉积学、地貌动力学等多学科互证,量化再现了珠江三角洲6~2.5 ka BP"镶嵌式"演变过程。  相似文献   

12.
The sedimentary sequence of the upper 4 m deposits in the Huanghe Harbour Pit is as follows, 1, Distributary mouth bar deposits formed before 1964; 2. lower delta plain (tidal flat) and subaqueous delta lateral deposits formed in the period of 1964-1972; 3. deposits of crevasse splay and distributary channel near mouth, formed in the period of 1972-1974; 4. tidal flat deposits formed in the period of 1975-1984. The sequence shows superimposition of sedimentary environments parallel to coastline.  相似文献   

13.
长三角一体化不只是陆域的一体化,还应包括海域的范围。为找出影响长三角海洋资源环境状况的主要因素及一体化治理的重点领域,从而丰富长三角一体化发展的研究,本文基于对长三角各沿海城市2009-2018年海洋生态系统服务价值的核算,通过静态面板与动态面板的综合分析,研究了人类行为活动对长三角海洋生态系统服务价值的影响。结果表明:1)各城市海洋生态系统服务价值均有增加,相同类别的海洋生态系统服务的价值变化相近;2)各城市海洋生态系统服务价值的比值相对稳定,但不同城市相同类别海洋生态系统服务的价值占比不同;3)长三角地区海洋资源环境的整体状况仍需改进;4)废水直排入海、工业废气排放、海水养殖、围填海等活动对区域海洋生态系统服务价值有较大影响;5)不同人类活动对区域海洋资源环境的影响机制不同,作用方向也不相同。据此,提出建议:1)依靠科技进步提升海洋生态系统服务价值水平,同时注重海洋生态系统文化服务的作用;2)从废水排放、废水直排入海、工业废气排放、海洋捕捞、围填海等影响区域海洋资源环境状况的主要因素入手,使治理工作精准化;3)不同城市应实施差异化治理。  相似文献   

14.
The central part of the Zagros Fold-Thrust Belt is characterized by a series of right-lateral and left-lateral transverse tear fault systems, some of them being ornamented by salt diapirs of the Late Precambrian–Early Cambrian Hormuz evaporitic series. Many deep-seated extensional faults, mainly along N–S and few along NW–SE and NE–SW, were formed or reactivated during the Late Precambrian–Early Cambrian and generated horsts and grabens. The extensional faults controlled deposition, distribution and thickness of the Hormuz series. Salt walls and diapirs initiated by the Early Paleozoic especially along the extensional faults. Long-term halokinesis gave rise to thin sedimentary cover above the salt diapirs and aggregated considerable volume of salt into the salt stocks. They created weak zones in the sedimentary cover, located approximately above the former and inactive deep-seated extensional faults. The N–S to NNE–SSW direction of tectonic shortening during the Neogene Zagros folding was sub-parallel with the strikes of the salt walls and rows of diapirs. Variations in thickness of the Hormuz series prepared differences in the basal friction on both sides of the Precambrian–Cambrian extensional faults, which facilitated the Zagros deformation front to advance faster wherever the salt layer was thicker. Consequently, a series of tear fault systems developed along the rows of salt diapirs approximately above the Precambrian–Cambrian extensional faults. Therefore, the present surface expressions of the tear fault systems developed within the sedimentary cover during the Zagros orogeny. Although the direction of the Zagros shortening could also potentially reactivate the basement faults as strike-slip structures, subsurface data and majority of the moderate-large earthquakes do not support basement involvement. This suggests that the tear fault systems are detached on top of the Hormuz series from the deep-seated Precambrian–Cambrian extensional faults in the basement.  相似文献   

15.
黄河口水下滑坡体系   总被引:38,自引:1,他引:38  
自1988年以来,通过多次野外考察和深入研究,在黄河口发现并确认存在大规模的水下滑坡体系。根据声纳图象和浅地层剖面记录,对滑坡进行分类命名和特征分析。研究表明,该滑坡体系中存在瓶颈状滑坡、平移板状滑坡和旋转滑坡3种类型;许多单个滑坡在下坡方向汇集成复合滑坡系统,有时数十条滑坡汇集成蜿蜒数公里的大规模复杂体系。滑坡冲沟分布广泛,将底坡表层切割得支离破碎,与密西西比河口比较,黄河口水下滑坡具有高含水、  相似文献   

16.
黄河三角洲下三角洲平原沉积环境   总被引:1,自引:1,他引:1  
现代黄河三角洲活动叶瓣上河口附近发育着决口扇沉积物,潮汐影响不明显。两侧发育着具有进积潮滩特点的沉积物。叶瓣废弃后由于压实下沉和波浪作用海岸后退,形成退积潮滩。在废弃河口侧部发育较好。那里高潮线处没有侵蚀陡坎,海岸后退是由于压实下沉引起的。废弃河口附近侵蚀作用明显,高潮线处发育侵蚀陡坎,潮间带变窄。  相似文献   

17.
长江河口三角洲区有孔虫沉降速度试验   总被引:7,自引:0,他引:7  
作者对有孔虫壳体沉降速度进行了测试和研究,提出了不同属种有孔虫的壳径与沉降速度相关方程,引进了“当量直径”的概念,并用于长江口三角洲地层中的化石群,提出了解释潮汐河口有孔虫埋葬群的形成机理,从而定量的研究和辨别三角洲地层中的原地埋葬和异地埋葬化石群。  相似文献   

18.
Offshore oil & gas industry is moving exploration and production activities into Arctic and deep water regions. Governmental regulations require environmental impact assessments before operations to evaluate the possible effects of accidental oil releases. These are often performed by numerical fate models, like the Oil Spill Contingency and Response (OSCAR) model, which has become an industry standard in Norway. In this model, biodegradation rates are adjusted to local conditions by temperature compensation according to a Q10 approach. Q10 is the multiplier by which rates of enzymatic reactions increase at a 10 °C temperature rise. Herein, this Q10 approach implemented in the OSCAR model is investigated based on published data and novel obtained results. Overall, biodegradation rate predictions calculated by temperature compensation are found to be questionable, and choosing one universal Q10 value is considered not feasible. The high variation in Q10 values is herein attributed to indirect effects of temperature.  相似文献   

19.
Evolution history and trend of the modern Huanghe River Delta   总被引:3,自引:1,他引:2  
The evolvement history of modern Huanghe River Delta tidal flat, coastline and underwater terrain were studied based on the analysis of remote sensing images and water depth data. Based on the analysis of seafloor terrain evolution on different historical stages, a formula simulating the erosion and deposition evolvement model of subaqueous Huanghe River Delta slope was proposed, and the evolvement trend of the subaqueous delta terrain was predicted. The result shows that the equilibrium transition zone is near the water depth of 12 m with seabed erosion in shallower water and accumulation in deeper water during the first 150 a after the river channel was deserted. In the meantime, the underwater slope became gentler and the coastal erosion rate became slow gradually. Then, the subaqueous delta slope changed to up concave from upper convex, and the shape of subaqueous delta disappeared. The coast type changed to silt-mud coast about 100-150 a after the river course was deserted. The erosion depth in the foot of the seawall is calculated based on the formula.  相似文献   

20.
Ancient lacustrine storm-deposits that act as petroleum reservoirs are seldom reported. The Lijin Sag, which is located in the southeastern corner of the Bohai Bay Basin in East China, is a NE–SW trending Cenozoic half-graben basin. Some of its Eocene deposits (Bindong deposits) were interpreted as lacustrine tempestites. The Bindong tempestites, which developed in the lower part of the upper fourth member of the Shahejie Formation (Es41), constitute a new kind of petroleum reservoir and are novel petroleum exploration targets in the Bindong Area. However, the characteristics of the Es41 Bindong tempestite reservoirs and their controlling factors are poorly understood. Point-count analyses of thin sections, scanning electron microscope image analyses, X-ray diffractometry data, and the petrophysical parameters of the Bindong tempestite reservoirs were utilized to estimate the reservoir quality. The reservoirs have undergone significant diagenetic alteration, which can be divided into negative and positive aspects. The negative alteration includes compaction, authigenic minerals, and cementation such as carbonates, clay minerals and overgrowths of quartz and feldspar. The uneven distribution of carbonate cement increased the reservoir’s heterogeneity, with carbonate cement commonly precipitating along the sandstone-mudstone contacts. The primary porosity was severely reduced because of compaction and extensive carbonate cementation. Positive alteration includes dissolution, carbonate cementation, undercompaction and fractures. Carbonate cementation exhibited both positive and negative effects on the reservoir quality. Overall, the objective reservoir quality is quite poor. A quantitative evaluation of the reservoirs’ potential was conducted. The cutoff values of several of the reservoir’s parameters were calculated. The lower limits of the porosity and permeability are 8.35–5.85% and 1.2587–0.2753 × 10–3 μm2, respectively, depending on the depth. The upper limits of the carbonate and mud content are approximately 18.5% and 9–10%, respectively. A fundamental understanding of these characteristics will provide necessary information for extracting hydrocarbons from analogous subsurface reservoirs.  相似文献   

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