Economic evaluation of using marine dredged material for erosion control along the northeast coast of the Nile Delta,Egypt

The present study is the first attempt in Egypt to assess feasibility of using of dredging material from Damietta Harbor in the northwestern Nile Delta for erosion control. The study also provides an economic evaluation for the shoreline management alternatives selected to mitigate for the effects of coastal erosion at two pilot eroding areas (namely, A and B) located near the Damietta Harbor. Results of compatibility analysis reveal that the dredging material is fairly compatible with the native sand of the nearby eroding beaches. In addition to soft nourishment by dredged sand, other types of coastal engineering measures which are often used in erosion management area were also evaluated as alternatives for erosion control and mitigation solution. Economic feasibility assessment by means of cost-benefit analysis of direct and indirect items has been carried out to facilitate comparison between these alternatives. Analysis of alternatives has been also supported by other criteria to select the cost-effective and environmentally acceptable option to protect the eroding pilot areas. These criteria include the high total cost paid for maintenance of the Damietta Harbor channel with no use, anticipated impacts on the littoral system, sustainability, future plans for protection of the existing coastlines, and lessons learned from previous shore protection works in the Nile Delta. The final selection of the best viable alternative indicates that the procedure of beach nourishment is the most appropriate form for protection area A, while a combination of groins and sand nourishment is more relevant for area B. In any case, material dredged from the navigation approach of the Damietta Harbor should be utilized as a borrow material in the nourishment schemes and excluding use of the terrestrial sources.     

Extraction of agar from Eucheuma cottonii and Gelidium amansii seaweeds with sonication pretreatment using autoclaving method

The effect of sonication pretreatment condition on Eucheuma cottonii and Gelidium amansii seaweed towards agar extraction wae studied. Four parameters were changed during sonication to investigate the effects on agar yield and quality. These parameters include the time interval, concentration ratio, frequency, and intensity. The highest amount of agar extracted from Eucheuma cottonii species could be obtained from the time interval of 30 min, seaweed weight to solvent volume ratio of 1:20, the frequency of 35 Hz, and the sonication power intensity of 30%. For Gelidium amansii species, the best agar yield also could be obtained from the time interval of 30 min, 1:20 of seaweed weight to water volume ratio, the frequency of 35 Hz, and power intensity of 30%. From the experiment, sonication pretreatment significantly influenced the yield and properties of extracted agar. The sonication with autoclaved seaweed produced agar containing less sulfate content, which is an excellent chemical property for gel electrophoresis applications.The gel strength of sonication with autoclaving for both seaweeds, Eucheuma and Gelidium species was the highest among those by sonication with direct heating, which proved that sonication pretreatment with autoclaving could enhance the physical properties of the agar.     

Genesis types of the Neoproterozoic Molar tooth structures in the southeastern Jilin and eastern Liaoning provinces and its research significances

Molar tooth (briefly called MT) carbonate is one of the Proterozoic carbonates with enigmatic sedimentary structure. According to the morphology of MT, it can be divided into two main genesis-morphology types, i.e., autochthonous and allochthonous, and each type can be further divided into a series of subtypes. The autochthonous MT can be divided into filamentous (MF1), ribbon, nodular and dotted type (MF4), in which the ribbon one can be subdivided into simple vertical (MF2) and complex ribbon (MF3), broken ribbon by storm in situ (MF5) and MT within nodular limestone (MF6). Allochthonous MT includes conglomerate clasts and horizontal detritus. Studying on the links between MT and the host rocks on five stratigraphic sections in the southeastern Jilin and eastern Liaoning indicates that the morphology of MT is closely related to host rocks, and seven genetic types by relationships between MT and the host rocks with facies interpretations are classified and discussed in this paper. The sedimentary environments of MT formation will be diverse if their morphologies are different.     

人工聚沙堤防治铁路沙害的初期试验研究

本文介绍了在高寒干旱的青藏铁路线伏沙梁地段,采用人工聚沙堤阻截外来风沙流的试验。通过初期试验观测,对人工聚沙堤的聚沙形式结构和防沙效果进行了阐述,提出人工聚沙堤是整治该段铁路沙害的一种主要措施。     

广西百色盆地重磁力结合遥感资料在盆地早期评价中的综合研究

本文以百色盆地为例,着重阐述了重磁资料在盆地早期评价中所起的重要作用,提出并总结了重磁资料在盆地早期评价系统中与遥感等资料综合研究的方法系列,指出重磁处理系统是盆地早期评价系统中不可分割的重要部分,遥感图像处理、石油重磁处理系统和地理信息系统(GIS)是进行多元信息综合的强有力的工具。     

伊犁盆地南缘中侏罗统西山窑组沉积环境讨论

伊犁盆地南缘是中国重要的煤和砂岩型铀矿富集区,中侏罗统西山窑组是主要的赋矿层位。基于对野外剖面的实测、室内岩矿鉴定、碎屑粒度统计分析和钻测井等资料的解释,明确了伊犁盆地南缘中侏罗统西山窑组的沉积环境类型、砂体成因、展布及其煤系地层分布的耦合关系。研究结果表明:伊犁盆地南缘西山窑组为曲流河三角洲平原-前缘沉积环境,分流河道微相的砂岩以高含煤屑或碳质、中粗结构、富岩屑和长石、分选性较差、中等磨圆为特征,具有较低的成分成熟度和结构成熟度。粒度曲线以三段式为主,显示了三角洲平原水道跳跃、滚动和悬浮搬运的特征。电阻率曲线纵向上表现为粒度向上变粗的逆粒序。砂体厚度多在20~40 m之间,砂地比值在0.3~0.8之间。分流河道砂岩与分流河道间沼泽相的煤层或泥炭在平面上毗邻、剖面上交互产出,古植物茎干化石和植物印痕多处存在。曲流河三角洲沉积环境和三角洲砂岩与煤系地层共生耦合关系的提出,对伊犁盆地南缘煤铀富集规律的深入研究提供了沉积学支持。     

北京平原区断裂构造重力异常识别研究

区域重力异常蕴含丰富的断裂构造特征信息.采用小波多尺度分解、归一化总水平导数垂向导数（NVDR_THDR）和剖面2.5D重力异常反演方法对北京平原区高精度区域重力资料进行了处理,获得了主要断裂构造平面位置、长度、规模、汇交关系及深浅延伸特征,分析了利用重力异常识别断裂的效果.结果表明：（1）北京平原区NE向断裂平面延展长度大、连续性强,NW向断裂分段性明显,连续性弱,但NW向断裂对NE向断裂有切割改造迹象.近EW或SN向断裂分布较为局限.（2）主控断裂平面和垂向延伸特征差异明显,顺义断裂、孙河断裂、永定河断裂等为盖层断裂;南口断裂、孙河断裂西段、二十里长山断裂和张喜庄断裂为基底断裂;黄庄—高丽营断裂南段、南苑—通县断裂、礼贤断裂、夏垫断裂和皮各庄断裂东段为地壳断裂.（3）利用NVDR_THDR峰值异常带的连续性、幅值、宽度及错切关系可有效识别断裂的平面展布特征,通过小波变换获得的不同深度等效层异常结合2.5D剖面反演可有效研究断裂在基岩内部的深浅延伸情况,但重力异常的垂向分辨能力弱,断裂在新生界内部延伸特征需结合其他地质资料进一步分析.

     

Interpretation models and charts of production profiles in horizontal wells

Stratified flow is common for the gravity segregation and flow regimes are very complex because of borehole inclination, therefore, all the conventional production logging tools cannot be effectively applied in horizontal wells, thus significantly increasing the difficulties in log interpretation. In this paper, firstly, the overseas progress in updated integration tools for horizontal wells and production profile interpretation methods has been discussed in brief. Secondly, by means of theory study and experimental simulations, we have obtained the production profile interpretation model and experimental interpretation charts, which have been calibrated by the improved downhole technology and optimization methods. Finally, we have interpreted X-well with the production profile interpretation software designed by us, and it proves that the methods are useful for the production profile interpretation in horizontal wells.     

二叠纪-三叠纪之交全球海平面变化研究

二叠纪-三叠纪界线附近的全球海平面变化是当前沉积学研究的热点和难点问题,其与当时的显生宙最大规模生物灭绝事件存在一定关联,具有重要的研究意义。然而二叠纪-三叠纪界线附近的全球海平面变化存在较多争议,受单剖面或区域范围内相对海平面变化研究程度的制约,在缺乏从沉积学角度的综合对比研究的情况下,可能会影响对全球海平面变化过程与持续时间的判识。综述了二叠纪-三叠纪界线附近的海平面变化研究进展,整合了多位学者的研究剖面、主要观点及认识,梳理了全球海平面变化的主要观点（“上升论”和“下降-上升论”）,包括其各自的发展历程、代表剖面及海平面变化识别特征、海平面上升/下降的原因以及海平面变化与生物灭绝的关系等,并在此基础上,探讨了二叠纪-三叠纪全球海平面变化研究过程中产生争议的原因。本文旨在为二叠纪-三叠纪界线（PTB）附近海平面变化研究提供线索,同时为研究全球PTB地质事件发生的背景及差异性原因提供基础证据。     

Use of receiver functions in wide-angle controlled-source crustal data sets

First-arrival waveforms remain underutilized in crustal refraction–reflection seismology by mostly reducing them to traveltime picks. However, as in earthquake seismology, the waveforms also contain important information about shallow near-receiver structures. We illustrate the use of three-component waveform analysis on the records from the ACCRETE wide-angle data set (SE Alaska and British Columbia; 1994), apply the Receiver Function (RF) methodology to the codas of P -wave arrivals, and draw two important conclusions. First, the P -wave polarization azimuths are found to be controlled by the near-receiver structures and virtually unrelated to the source–receiver backazimuths, from which they deviate by up to ∼40°. This observation might be important for studies of anisotropy and also for earthquake RF studies. Second, after correcting for the polarization azimuths, clear P / S mode conversions are reliably detected within 80–400 ms following the primary arrivals. The conversions are interpreted as originating at the base of the sedimentary cover of the fjord channel. In most cases, imaging of the basement requires only several records; however, notable exceptions are also found and interpreted as caused by multipathing, localized scattering, and onsets of crustal and Moho reflections. The ACCRETE example shows that RF methodology could be useful for constraining sediment thickness and deriving P - and S -wave receiver statics in land refraction surveys where collocated reflection profiles are not available. In addition, RFs from repeatable controlled sources could be useful for testing and calibration of RF techniques.