Gravity Fault Subsidence and Beach Ridges Progradation in Quinta-Cassino (RS) Coastal Plain, Brazil

Ground penetrating radar (GPR) surveys have being applied to investigate very near-surface stratification of sedimentary units in coastal plains and to define their depositional conditions. This paper presents, however, low-frequency GPR survey to investigate fault-related depositional systems at greater depths. The Quinta-Cassino area in the Rio Grande do Sul Coastal Plain (RGSCP, Brazil) shows a wide strandplain that is made off by very long, continuous, and linear geomorphic features (beach ridges). This strandplain extends for ~70 km southward. The beach ridges show low-angle truncations against the Quinta escarpment, and also truncations in the strandplain. The traditional approach points that RGSCP was developed by juxtaposition of four lagoons/barrier systems as consequence of sea level changes;previous model assumes that no deformational episode occurred in RGSCP. The geophysical and geological surveys carried out in this area showed the existence of listric fault controlling the beach ridges in the escarpments and hanging-wall blocks. The radargrams could distinguish Pleistocene basement unit anticlockwise rotation, thickening of beach ridges radarfacies close to listric normal faults, and horst structures. These deformational features indicate that the extensional zone of a large-scale gravity-driven structure controlled the mechanical subsidence, the Holocene sedimentation and its stratigraphic and geomorphic features in the Quinta-Cassino area to build up an asymmetric delta. The results point to a new approach in dealing with RGSCP Holocene evolution.

澳大利亚悉尼Long Reef Beach中新世古土壤岩石磁学特征及环境意义

本文对发育在澳大利亚悉尼附近的Long Reef Beach中新世古土壤剖面进行了系统的岩石磁学研究,测量了磁化率、饱和磁化强度、饱和等温剩磁、非磁滞剩磁等常温磁学参数和磁滞回线,并对所有样品进行了热磁分析.实验结果表明:全新世软土层主要磁性矿物为MD颗粒磁铁矿,磁性矿物含量与黄土高原黄土层相当.中新世老成土层随地层深度增加主要磁性矿物由磁铁矿转变为磁赤铁矿,随着磁铁矿向磁赤铁矿的转化,开始出现赤铁矿;磁性矿物粒径分布较广,以PSD颗粒为主,其次为SD颗粒,同时含有少量MD颗粒;磁性矿物含量高于黄土高原强发育古土壤层.中新世红土矿层主要磁性矿物为赤铁矿,同时含有少量磁赤铁矿和针铁矿,属于铁的富集层,赤铁矿以SD颗粒为主,含少量PSD和MD颗粒.Long Reef Beach中新世古土壤形成时期,对应着一种全球性高温多雨气候,地表化学风化作用十分强烈.丰富的降水,导致中新世老成土层发生淋溶作用,磁铁矿在向下淋溶迁移过程中逐渐氧化为磁赤铁矿和赤铁矿,铁氧化物最终在红土矿层淀积,磁赤铁矿经高温压实作用再结晶转化为赤铁矿.磁性矿物转化过程可概括为磁铁矿—磁赤铁矿化的磁铁矿—磁赤铁矿—赤铁矿,其中部分磁赤铁矿具有热稳定性,在空气(氩气)环境中加热到700℃未发生转化.

应用Beach marking方法检测钢结构疲劳裂纹扩展

掌握裂纹扩展规律是钢结构疲劳性能研究的一个基本问题。本文介绍了一种检测钢结构疲劳裂纹扩展的新型方法,即Beach marking方法。论文首先简述了这种方法测试疲劳裂纹扩展的基本原理,然后通过一个试验案例,展示了这种方法的具体应用和要点试验表明这种方法简单实用,通过运用合适的疲劳荷载序列,可在疲劳断口留下疲劳弧线,从而间接有效地记录了疲劳裂纹的扩展全过程。

Morphodynamics of an Artificial Cobble Beach in Tianquan Bay, Xiamen, China

By tracking and monitoring the profile configuration, topography, and hydrodynamic factors of an artificial cobble beach in Tianquan Bay, Xiamen, China over three consecutive years after its completion, we analyzed the evolution of its profile configura- tion and plane morphology, and its storm response characteristics. The evolution of the profile configuration of the artificial cobble beach in Tianquan Bay can be divided into four stages. The beach was unstable during the initial stage after the beach nourishment the profile configuration changed obviously, and an upper concave composite cobble beach formed gradually, which was character- ized by a steep upper part and a gentle lower part. In the second stage, the cobble beach approached dynamic equilibrium with minor changes in the profile configuration. At the third stage the beach was in a high-energy state under the influence of Typhoon Meranti, and the response of the artificial cobble beach differed significantly from that of the low-tide terrace sandy beach. Within a short time, there was net onshore transport of cobbles in the cross-shore direction. The beach face was eroded, the beach berm was accumulated, and the slope of the beach was steepened considerably. In the alongshore direction, there was notable transport of cobbles on the beach from east to west along the shore, and the total volume of the beach decreased by 4.5×103 m 3, which accounted for 50% of the total amount of beach volume lost within three years. The fourth stage was the restoration stage after the typhoon, characterized by a little gentler profile slope and the increase in width and the decrease in height of beach berm. Because of the action of waves and the wave-driven longshore current caused by the specific terrain and landform conditions along the coast (e.g., coastal headlands, near-shore artificial structures, and reefs), the coastline of the artificial cobble beach gradually evolved from being essentially parallel to the artificial coast upon completion to a slightly curved parabolic shape, and three distinct erosion hotspots were formed on the west side of the cape and the artificial drainpipe, and the reefs. Generally, the adoption of cobbles for beach nourishment on this macro-tidal coast beach with severe erosion has yielded excellent stability and adaptability.

Shoreline Change Modeling on Emergency Beach Nourishment Project on West Beach of Beidaihe,China

By use of a shorehne-change numerical model （GENESIS） based on one-line theory, a preliminary modeling study on shoreline changes caused by a beach nourishment project in Beidaihe, China, is presented in this paper. Firstly, the GENESIS model is verified and model sensitivity to the major parameter changes is discussed by simulating a hydraulic model test. The beach nourishment project, after that the shoreline change is kept being monitored, is a small-scale emergency one carried out to use two bathing places on the west beach in the summer, 2008. In this paper the shoreline changes caused by the beach nourishment project are modeled by the GENESIS model, and the computed results fit well with the measured shorelines. With the same model and parameters, a long-term performance of the project is predicted, and the result shows that the bathing places only can be suitable for bathing in 2 to 3 years without subsequence nourishment project. Therefore, it is proposed to nourish the beaches in time to keep the service life of the beach in recent years and carry out the beach nourishment project for the whole west beach as soon as possible.

Effect of reductant type on the embedding direct reduction of beach titanomagnetite concentrate

Iron and titanium were recovered from beach titanomagnetite(TTM) concentrate by embedding direct reduction and magnetic separation. The reduction products and the effects of the reductant type and reduction temperature on the reduction behavior were investigated. The results showed that the reduction of TTM concentrate was strongly related to the gasification reactivity of the reductant. Bitumite presented a better product index than wheat-straw biochar and coke, mainly because the gasification reactivity of bitumite was better than that of the other reductants. In addition, high temperatures were not beneficial to embedding direct reduction because of the emergence of a molten phase and iron-joined crystals, which in turn reduced the diffusion rate of the reducing gas and impeded the reduction reaction in the central area of the roasted briquette. The use of bitumite as the reductant at a C/Fe molar ratio of 1.4 and a reduction temperature of 1200°C for 120 min resulted in direct-reduction iron powder assaying 90.28 wt% TFe and 0.91 wt% TiO_2 with an iron recovery of 91.83% and titanium concentrate assaying 46.01 wt% TiO_2 with a TiO_2 recovery of 91.19%. Titanium existed mainly in the form of anosovite and ilmenite in the titanium concentrate.

Numerical study of shoreline changes by emergency beach nourishment project at the Middle Beach of Beidaihe, China

Beach nourishment is a common coastal management strategy used to protect beach from erosion along the sandy coastlines. This method has been successfully applied to an emergency project at the West Beach of Beidaihe in the summer of 2008 and the full West Beach nourishment project in 2009-2010, which is the direct base of this study. Some basic information about the emergency engineering area at the Middle Beach is firstly described. The shoreline change of this area, including the analysis of beach width in five monitoring profiles in the bathing places of Middle Beach, is then discussed. After that a numerical modal based on one-line theory is established and the numerical results agree well with the measured shorelines, which indicates that the model is appropriate and is qualified to predict the shoreline change of the Middle Beach. With the same model and parameters, long-term performance of the project is predicted, and the result shows that without follow-up nourishment and project, the bathing places can remain suitable for bathing for about 10 a. It is suggested to nourish the beach in time and carry out the beach nourishment project for the full Middle Beach in Beidaihe.

A geomorphological response of beaches to Typhoon Meari in the eastern Shandong Peninsula in China

Eight representative beach profiles on the eastern coast of the Shandong Peninsula are observed and measured in 2011 and 2012 to determine the coastal processes under the lower tropical wind speed condition and the beach response to and recovery from the tropical storm Meari in a rare typhoon region. The results show that it is the enhancement and directional change of cross-shore and longshore sediment transports caused by Meari that leads to the beach morphological changes, and most of the sediment transports occur during the pre-Meari landing phase. The erosional scarp formation and the berm or beach face erosion are the main geomorphological responses of the beaches to the storm. The storm characteristics are more important than the beach shapes in the storm response process of the beaches on Shandong Peninsula. The typhoon is a fortuitous strong dynamic event, and the effect on the dissipative beach is more obvious than it is on the reflective beach in the study region. Furthermore, the beach trend is the main factor that controlls the storm effect intensity, and it is also closely related to the recovery of the beach profiles.

The sedimentary source, planform stability and shore normal morphological change of the Xichong beach on the southern coast of the Dapeng Peninsula of Shenzhen, Guangdong Province, China

The coast of the Dapeng Peninsula has been honored as one of “the eight most beautiful coasts in China”. The most precious tourism resource for the peninsula is headland bay beaches, among which the beach at Xichong on the southern coast of the peninsula is the longest and the most important one. The information of the stability, sedimentary source and shape change of the beach is very important for maintaining the beach in terms of sustainable development of the peninsula. Heavy minerals in the sand of the beach and the inland stream at Xichong are compared with those of a nearby beach on the same coast to determine the beach sand source; with help of a computer software, MEPBAY, the equilibrium planforms of the beaches on the peninsula are compared with those of an island without rivers to evaluate the stream＇s effects on the beach stability; cross shore profiles along the Xichong beach are also surveyed in different seasons of a year to assess the annual shore normal beach changes affected by the stream input, and the relation between the equilibrium planform state and cross shore changes of the beach. It is shown that （1） stream is the main sedimentary source of the beach and the weathering materials of the rocky headlands on both sides of the bay transported by waves are the second source for the beach but it is limited, sand from an inner shelf is not the sedimentary source for the beach at present and was not even during the Holocene transgression; （2） the Xichong beach cannot reach static equilibrium around the entire bay shoreline, the segment of the shore-line where a stream outlet is located is in dynamic equilibrium, and the unstable section occurs in the wave shadow region in the lee of an offshore island; （3） no matter whether the section of the beach shoreline at Xichong is in an equilibrium state or not, it is eroded in the typhoon season and recovered after the season, the maximum change in erosion and accretion occurs in the unstable segment; （4） the Xichong beach can only have small sand body since it is supplied with sand mainly form inland streams, resulting in a possible danger in which sand loss induced by human activities or huge storms cannot be replenished naturally.

Diagenetic Evolution and Formation Mechanisms of High-Quality Reservoirs under Multiple Diagenetic Environmental Constraints:An Example from the Paleogene Beach-Bar Sandstone Reservoirs in the Dongying Depression,Bohai Bay Basin

The diagenetic environment, diagenetic responses, diagenetic transformation model and formation mechanisms of high-quality reservoirs（beach-bar sandstones of the Paleogene fourth member） in the Dongying depression were studied through the analysis of fluid inclusions, thin section and burial evolution history. The diagenetic fluids of the beach-bar sandstone reservoirs evolved from early high salinity and weak alkalinity to low salinity and strong acidity, late high salinity and strong alkalinity and late low salinity and acidity, which were accompanied by two stages of oil and gas filling. The fluids at the margins of the sandbodies were continuously highly saline and strongly alkaline. The western（eastern） reservoirs experienced early open（closed）, middle open, and late closed diagenetic environments during their burial history. The flow pattern was characterized by upwelling during the majority of the diagenesis（in the east, a non-circulating pattern transitioned into an upwelling current）. Due to the evolution of the diagenetic fluids, the diagenetic sequence of the beach-bar reservoirs was as follows： early weak carbonate cementation; feldspar and carbonate cement dissolution and authigenic quartz cementation; late carbonate and anhydrite cementation, authigenic feldspar cementation, and late quartz dissolution; and late carbonate cementation, feldspar dissolution, and authigenic quartz cementation. The diagenetic strength during these stages varied or was absent altogether in different parts of the reservoirs. Due to the closeness of the diagenetic environment and the flow pattern of the diagenetic fluids, the diagenetic products are variably distributed in the sandstones interbedded with mudstones and in the fault blocks. The evolution of multiple alternating alkaline and acidic diagenetic environments controlled the distribution patterns of the reservoir diagenesis and reservoir space, and the reservoir quality index, RQI, increased gradually from the margins to the centers of the sandstones. The closeness of the diagenetic environment and the flow patterns of the diagenetic fluids controlled the differences in the reservoir properties among the fault blocks. With increasing distance from the oil-source faults, the RQI values in the west gradually decreased and in the east initially increased and then decreased.

Instrumental neutron activation analysis of beachrock samples of South East Coast of Tamilnadu,India

Element profiles of some beach rock samples collected from South East Coast of Tamilnadu, India have been determined using single comparator method of INAA. The geo-chemical behavior of the elements in the region is discussed. The irradiations were done at thermal neutron flux of ~ 1011 cm-2·s-1 at 20kW power using Kalpakkam Mini Reactor (KAMINI), IGCAR, Kalpakkam, Tamilnadu, India. Around 19 elements have been determined from 15 samples by high-resolution gamma spectrometry. The accuracy and precision were evaluated by assaying the irradiated Standard Reference Material (SRM 1646a Estuarine sediment) and were found to be in good agreement with certified values.

Analysis of the dynamic characteristics and stochastic simulation on variations of beach volumes

This paper analyzes the dynamic characteristics of the variations of the beach volumes for three level zonesof the Yanjing Beach in the Shuidong Bay of the western Guangdong Province by using the methods of dynamic systemanalysis and the multi-dimensional spectral estimation. The results show that the variations of the beach volume arecharaCterized by the multiband oscillations with a dominant semimonth period. Upwards the low tide level, the beachtends to be stable. The estimates of the partial coherences and the partial phases indicate that the variations of thebeach volumes are mainly the results of the direct actions of the waves which are influenced by the tidal level changesand driven by the wind stress. The simulation results of the beach volume series for different beach heart zones bythreshold mixed regressive models indicate that the influence of the tide on the variations of the beach volumes is weakened and the direct actions of the wave energy and the wind stress are apparently enhanced with the increase of thebeach height.(This project was supported by the National Natural Science Foundation of China.)

Hydrocarbon accumulation characteristics of beachbar sandstones in the southern slope of the Dongying Sag, Jiyang Depression, Bohai Bay Basin, China

A number of beach-bar sandstone reservoir beds are developed in the upper fourth member of the Eocene Shahejie Formation （Es4s） on the southern slope of the Dongying Sag.Based on the analysis of seismic and logging data,with characterization and petrographic studies of core and cutting samples,this paper analyzes the hydrocarbon accumulation characteristics in two typical blocks of the Boxing and Wangjiagang oilfields,especially reservoir bed heterogeneity and migration conditions that influence oil and gas distribution,calculates the index of reservoir bed quality （IRQ） with a mathematical method,and discusses the relationship between driving force and resistance of hydrocarbon accumulation.Taking into account the characteristics of thin interbeds in beach-bar sandstones,an experimental model simulated the characteristics of hydrocarbon migration and accumulation in thin interbedded sandstones with reservoir bed heterogeneity.The results showed that hydrocarbon distribution and properties were extremely non-uniform.Reservoir bed and migration conditions controlled hydrocarbon accumulation in beach-bar sandstones.IRQ is above 0.4 in the main hydrocarbon region.Sand body distribution,structural configuration and fault systems controlled the direction of regional migration and location of hydrocarbon accumulation.Simulation experiments indicated that the change of driving force for hydrocarbon migration affected selective accumulation mechanisms.Hydrocarbon moved vertically along fault zones to the reservoir and resulted in the distribution of hydrocarbon in the reservoir.Two kinds of hydrocarbon accumulation models exist in the study area.One is a hydrocarbon accumulation model controlled by reservoir bed heterogeneity and the second is a hydrocarbon accumulation model controlled by a complex migration system with faults connecting sandbodies.Finally,different exploration strategies should be adopted for the detailed exploration for beach-bar sandstone reservoirs according to different geological backgrounds.

Spatial Variations in Particle Size and Magnetite Concentration on Cedar Beach:Implications for Grain-Sorting Processes,Western Lake Erie,Canada

This study examined spatial variations in the concentration,grain size and heavy mineral assemblages on Cedar Beach（Lake Erie,Canada）.Magnetic studies of heavy mineral-enriched,dark-reddish sands present on the beach showed that magnetite（～150μm） is the dominant magnetic mineral.Surficial magnetic susceptibility values defined three zones：a lakeward region close to the water line（Zone 1）,the upper swash zone（Zone 2） and the region landwards of the upper swash zone （Zone 3）.Zone 2 showed the highest bulk and mass susceptibility（κ,χ） and the highest mass percentage of smaller grain-size（250μm） fractions in the bulk sand sample.Susceptibility（i.e.κandχ） values decreased and grain size coarsened from Zone 2 lakewards（into Zone 1） and landwards （into Zone 3）,and correlated with the distribution of the heavy mineral assemblage,most probably reflecting preferential separation of large,less dense particles by waves and currents both along and across the beach.The eroded western section of Cedar Beach showed much higher concentrations of heavy minerals including magnetite,and finer sand grain sizes than the accreting eastern section, suggesting that magnetic techniques could be used as a rapid,cost-effective way of examining erosion along sensitive coastline areas.

Siltation Prediction for Navigation Channels and Harbour Basins on Muddy Beach

This paper, after briefly reviewing the experimental research on sediment transport on muddy beach since the 1950s, improves and perfects the method for forecasting siltation in navigation channels and harbour basins which was first put forward in China by the authors. In consideration of silty sediment and sand, some factors in forecasting methods have been changed and modified. Consequently, the modified methods can be used either to compute siltation in navigation channels and harbour basins on muddy beach or to compute siltation and scouring in navigation channels and harbour basins on both silty beach and sandy beach. The verification of field data from eleven large, medium and small natural harbours shows a good agreement between the forecasting by the modified method and the natural conditions. Finally, the paper deals with the rational utilization of water area after the construction of the West Dyke in Lianyungang, the maintenance of water depth of the navigation channel at the entrance, siltation distribution, siltation in the navigation channel and harbour basin for ships of 100 thousand tonnnage. Results once again prove that the prospect of constructing Lianyungang Harbour into a deepwater harbour is bright.

Morphodynamics of sandy beaches under the influence of storm sequences:Current research status and future needs

This paper reviews and discusses the current research status, trends, and future needs in the field of beach morphodynamics under the influence of storm sequences.The paper reviews how the three main research methods, field investigations, numerical modelling, and physical modelling, have been used to study beach morphodynamics during storm sequences.Available quantitative definitions of storm sequences at different sites are presented and discussed.It is shown that the definition of storm sequences is site-specific and requires knowledge of the storm climate, beach characteristics, and the temporal scale of beach recovery.Subsequently, the paper brings together currently available approaches aimed at describing the effect of storm sequences on beach erosion in a general way.The importance of storm chronology and the effects of an extreme storm within a sequence of storms are highlighted.Following that, the more poorly studied aspect of beach recovery in between storms within a sequence is discussed.Three indicators for defining beach recovery, namely the shoreline location, sediment volumes, and the beach state, are identified and compared.Finally, important research needs, including the need for detailed physical modelling, are identified.

Construction and Application of High Temperature Heat Damage Index for River Crab Culture in Hongze Lake Beach

Agrometeorology and agricultural statistics methods were used to analyze the cases of high temperature heat damage to crab breeding since 2008 in Hongze Lake Beach, finding that the high temperature heat damage was mainly under the comprehensive effects of the highest temperature, duration of high temperature weather, amount of precipitation and sunshine hours. Based on the function relation between the high temperature heat damage index and the influence factors, the linear model was used to describe the weight coefficient of each heat damage factor by using the synthesis correlation of multiple factors. The historical values of the influencing factors were used to make statistical calculation of the heat damage index model of crab culture in Hongze Lake Beach, which achieved good effects when applied in the meteorological operation of river crab culture.

Draft genome sequence of a less-known wild Vigna: Beach pea(V. marina cv. ANBp-14-03)

Beach pea or beach cowpea(Vigna marina(Burm.)Merr.)belongs to the family Fabaceae.It is a close relative of cultivated Vigna species such as adzuki bean(V.angularis),cowpea(V.unguiculata),mung bean(V.radiata),and blackgram(V.mungo),and is distributed throughout the tropics.With its ability to tolerate salt stress,beach pea has great potential to contribute salt-tolerance genes for developing salt-tolerant cultivars in cultivated Vigna species.However,it is still underutilized in Vigna breeding programs.A draft genome sequence of beach pea was generated using a high-throughput next-generation sequencing platform,yielding 23.7 Gb of sequence from 79,929,868 filtered reads.A de novo genome assembly containing 68,731 scaffolds gave an N50 length of 10,272 bp and the assembled sequences totaled 365.6 Mb.A total of 35,448 SSRs,including 3574 compound SSRs,were identified and primer pairs for most of these SSRs were designed.Genome analysis identified 50,670 genes with mean coding sequence length 1042 bp.Phylogenetic analysis revealed highest sequence similarity with V.angularis,followed by V.radiata.Comparison with the V.angularis genome revealed 16,699 SNPs and 2253 InDels and comparison with the V.radiata genome revealed 17,538 SNPs and 2300 InDels.To our knowledge this is the first draft genome sequence of beach pea derived from an accession(ANBp-14-03)adapted locally in the Andaman and Nicobar Islands of India.The draft genome sequence may facilitate the genetic enhancement in cultivated Vigna species.

Beach Profiles Characteristics Along Giao Thuy and Hai Hau Coasts,Vietnam:A Field Study

Giao Thuy and Hai Hau coasts are located in Nam Dinh province, Vietnam, with a total coastline of 54.42 km in length. The sea-dike system has been seriously damaged and there have been many dike breaches which caused floods and losses. This situation is considered of a general representative for coastal area in the northern part of Vietnam. A variety of studies have shown that the gradient in the longshore sediment transport rate and the offshore fine sediment lost are the main mechanisms causing the beach erosion. This study presents a field investigation of the beach profiles at Giao Thuy and Hai Hau beaches. Three types of empirical functions for the equilibrium beach profile are applied and compared with the observations. Results show that all observed beach profiles can be described by a single function. However, one specific equilibrium profile equation is not sufficient to assess all beach profiles. In Section 1 of Giao Thuy and Section 3 of Hai Thinh beaches, beach profiles are consistent with the logarithmic function, while the exponential function fits well in Section 2. This difference is explained with respect to coastal morphology, sediment characteristics and hydrodynamic conditions which vary in site. An analysis of the validity of the beach profile functions is recommended for the numerical modeling and engineering designs in this area.

Typical Equilibrium Beach Profile Models and Their Significances from Different Segments of A Headland-Bay Beach

This study introduces three typical models on equilibrium beach profile, and discusses the application limitations of these models. Then this study examines the selections for applying these models on different coastal segments of a headland-bay beach in west Guangdong, South China, and explores the physical significances of those parameters in the models. The results indicate that：（1） Bodge＇s model is more in line with the equilibrium beach profile of the tangential or transitional segment, whereas Lee＇s model is more consistent with the shadow profile;（2） most of the parameters in three models have clear physical significances in accordance with the actual characteristics of this headland-bay beach; and（3） both the selections for the equilibrium beach profile from different segments and significances of most of the parameters in three models are in essence correlated with the morphodynamic states at various coastal locations.