centrifuge modeling of dynamic response of high fill slope by using generalized scaling law abstract the development of physical modeling for mega engineering prototypes requires sophisticated use of the capability of current centrifuge facilities in this study centrifuge model tests were performed to investigate the dynamic response of high fill slope by using generalized scaling law in an improved way firstly the two stage generalized scaling law was partly re organized by considering the separate similitude of dynamic strain for the virtual 1 g field to solve the inherent problem of the scaling of soil strain when the derived prototype strain exceeded some important thresholds then a series of centrifuge model tests were conducted under different centrifugal accelerations to model a high fill slope with a prototype height of 100 m by the approach of modeling of models dynamic responses under sine waves with different amplitudes were monitored and the re organized generalized scaling law was validated for nonlinear dynamic response with shear strain less than 1 it was observed that site amplification of high fill slope was affected by both soil nonlinearity and soil strata non uniformity where soil nonlinearity led to smaller acceleration amplification under stronger excitation and soil strata non uniformity contributed to the acceleration de amplification and larger displacement amplification at the weak sublayer the large dynamic displacement near the slope surface consequently contributes to the development of lateral cracks after strong shaking seismic response under earthquake motions revealed that high fill slope with inclined non uniform strata was characterized by multiple vibration modes and lower fundamental frequency which was more vulnerable to earthquake motions with abundant frequency components this study provides a more physically meaningful use of the similitude of dynamic stress strain relation in centrifuge modeling for large scale geotechnical problems under dynamic loadings

seismic damage and behavior analysis of earth dams during the 2008 wenchuan earthquake china abstract the may 12 2008 ms 8 0 wenchuan great earthquake china caused earthquake damages of 2666 earth dams these damaged dams are in medium and small scale located in 8 provinces or municipalities of which 69 dams were at dam break risk and 331 were at high risk there were 1996 damaged dams located in sichuan province including all the 69 at dam break risk and 310 at high risk through a detailed scientific investigation earthquake damage and emergency data were collected and the isoseismal map of wenchuan earthquake with damaged dams marked on it was given also distribution feature of the above 69 dams along the fault zones were discussed typical damage types of earth dams were analyzed and the action of rare great earthquake poor quality of dam construction adverse running state of earth dams before earthquake and frequent aftershocks were concluded as four main reasons of dam damages taking 147 dams with complete geometric parameters as statistical samples some empirical graphic formulas were proposed to make rapid evaluation of damage degree finally some useful practical measures were provided to serve the post earthquake emergency danger removal also it may improve the seismic performance of dams in view of the insufficiency of local geology site effect and soil property data of damaged dams application of the qualitative results and empirical relationships to other sites should be very prudent

integrated tephrochronology and magnetostratigraphy for cyclothemic marine strata wanganui basin implications for the pliocene pleistocene boundary in new zealand abstract the middle pliocene to earliest pleistocene part of the rangitikei river section in wanganui basin contains at least six distal tephras five are rhyolitic kowhai eagle hill ohingaiti waipura and vinegar hill tephras and one is andesitic mangamako tephra all tephras occur as macroscopic layers and are enclosed within cyclothemic marine sediments that accumulated in shoreface to outer shelf water depths under conditions of oscillating sea level driven by glacio eustacy the glass and ferromagnesian compositions of the silicic tephras imply derivation from calc alkaline rhyolitic sources either or both of taupo volcanic zone and southern coromandel volcanic zone the waipuru and vinegar hill tephras have isothermal plateau fission track itpft ages of 1 87 0 15 ma and 1 75 0 13 ma respectively paleomagnetic results allow identification of i the gauss matuyama boundary located ca 70 m below the top of the mangaweka mudstone and ii the top of the olduvai subchron placed at the base of the waipuru shellbed the itpft ages of the tephras are consistent with the interpreted magnetostratigraphy and also with astronomically tuned timescales correlation of the rangitikei sequences to the odp site 846 18o record indicates that each sequence corresponds to a glacial interglacial isotope stage couplet and allows ages to be interpolated for tephras not dated directly integration of the new ages for the waipuru and vinegar hill tephras the magnetostratigraphy and the sequence correlations to the astronomically tuned oxygen isotope timescale lead us to place the pliocene pleistocene boundary as defined at the vrica stratotype at the base of the highstand systems tract siltstone of sequence 17 in the rangitikei section 60 m below the vinegar hill tephra

fuzzy evaluation on seismic behavior of reservoir dams during the 2008 wenchuan earthquake china the post earthquake rapid risk evaluation on the reservoir dams plays an important role in the emergency danger disposal and reinforcement the fuzzy data envelopment analysis assurance region dea ar approach was introduced evaluating the seismic behavior of reservoir dams in which the seismic risk of dam site the structure characteristics of reservoir dam and pre earthquake state of dams were taken as input variables in the meantime the seismic crack leakage and deformation of dams induced by the earthquake were taken as output variables the proposed dea ar approach was adopted to evaluate the seismic behavior of 19 reservoir dams suffered from wenchuan earthquake in luojiang county sichuan province the input and output variable values all originated from the post earthquake field investigation data and the weight values of dea ar model were determined by the entropy weight method which was able to avoid the interference from subjective consciousness the evaluation results on the seismic behavior obtained from dea ar approach were mainly consistent with those from the experts in the field which verified that the approach was valid and rational the proposed dea ar approach was based on the objective data and the cognitive ability of the model self to give the evaluation results which was adaptive for the situation that the seismic behaviors of the reservoir dams were not easy to distinguish a ranking method was recommended to judge the order of quality of seismic behavior of the evaluated reservoir dams the ranking results could serve for the post earthquake emergency disposal and reinforcement

quantitative evaluation and prediction of water inrush vulnerability from aquifers overlying coal seams in donghuantuo coal mine china the water inrush vulnerability from overlying aquifers is evaluated for a coal seam in the donghuantuo coal mine china the water inrush vulnerability is based on superposition of two zoning maps water abundance map and connectivity map the water abundance zoning map was derived from a comprehensive analysis of six types of geoscience data including 1 lithological changes of the overlying aquifer 2 geological structure 3 pumping test results 4 seepage field of water inrush event 5 geochemistry and 6 loss of drilling mud the connectivity map was constructed based on comparing the numerically calculated height of the induced fracture zone above mining areas with the thickness of formation between the coal seam and the overlying aquifer visual modflow was used to predict the mine discharges at working face 2 284 under both natural and mining conditions based on the water inrush vulnerability map and the modeling results advanced dewatering from the overlying aquifer is proposed as the main prevention and control measure against the overlying aquifer water inrush

sea level and climate signatures recorded in orbitally forced continental margin deposits over the last 1 myr new perspectives from the bohai sea abstract sediment accumulation in continental margins during the quaternary period was substantially influenced by both sea level fluctuations and climate changes however the response of sediment accumulation to these changes on an orbital timescale remains poorly understood for two main reasons the scarcity of sedimentary records with a high resolution chronology and the difficulty in distinguishing the role of sea level from regional climate signals here we present the results of sediment color reflectance c grain size and total organic carbon toc content of core bh08 212 4 m in length spanning the last 1 myr recovered from the bohai sea china the chronology of core bh08 on the orbital timescale is constrained by both magnetostratigraphy and astronomical tuning sedimentary facies analysis suggests that the sedimentary sequence is dominated by the alternation of a deltaic system and floodplain deposition principal components analysis of the grain size data reveals two principal components pcs including pc1 reflecting the 31 500 m fraction and pc2 reflecting the 18 66 m fraction comparison of sample scores on pc1 pc2 and c with the alternation of sedimentary environments reveals that pc1 and c reflect cycles of deltaic and floodplain deposition at 100 kyr and 40 kyr periodicities while pc2 exhibits a 20 kyr periodicity in addition to the 100 kyr and 40 kyr cycles we infer that pc1 and c are mainly sea level dependent whereas pc2 is controlled by the combination of changes in monsoon climate and sea level we suggest that milankovitch scale monsoon climate fluctuations controlled the sediments supply to the bohai sea during the last 1 myr while the redistribution of sediments by marine processes e g tidal currents has partially obscured the monsoonal signal in the grain size proxy e g pc1 which instead is sensitive to sea level change our results provide an example of the influence of climate and sea level on sediment accumulation in a shallow continental margin setting influenced by monsoonal climate in an icehouse world

stable isotope 2h 18o and 87sr 86sr and hydrochemistry monitoring for groundwater hydrodynamics analysis in a karst aquifer gran sasso central italy this paper deals with chemical and isotope analyses of 21 springs which were monitored 3 times in the course of 2001 the monitoring program was focused on the groundwater of the gran sasso carbonate karst aquifer central italy typical of the mountainous mediterranean area based on the hydrogeological setting of the study area 6 groups of springs with different groundwater circulation patterns were distinguished the hydrogeochemistry of their main components provided additional information about groundwater flowpaths confirming the proposed classification the spatial distribution of their ion concentrations validated the assumptions underlying the hydrogeological conceptual model showing diverging groundwater flowpaths from the core to the boundaries of the aquifer geochemical modelling and saturation index computation elucidated water carbonate rock interaction contribution by alluvial aquifers at the karst aquifer boundaries as well as impacts of human activities the analysis of 18o 16o and 2h h values and their spatial distribution in the aquifer substantiated the hydrogeology based classification of 6 groups of springs making it possible to trace back groundwater recharge areas based on mean isotope elevations the latter were calculated by using two rain monitoring stations 87sr 86sr analyses showed seasonal changes in many springs in winter spring the changes are due to inflow of new recharge water infiltrating into younger rocks and thus increasing 87sr 86sr values in summer autumn when there is no recharge and spring discharge declines changes are due to base flow groundwater circulating in more ancient rocks with a subsequent drop in 87sr 86sr values the results of this study stress the contribution that spatio temporal isotope monitoring can give to the definition of groundwater flowpaths and hydrodynamics in fissured and karst aquifers taking into account their hydrogeological and hydrogeochemical setting

fluvial response to late quaternary climate changes western india we review here the fluvial response to late quaternary climatic changes in the semi arid regions of western india i e the thar desert and its margins and maharashtra the rivers in the thar desert show a spectrum of environments from gravel bedload braided to ephemeral sand bed streams to sheet flows and sheet floods while those in the thar margin and maharashtra show dominantly two modes i e braided and meandering rivers the streams became defunct and aeolian sands were deposited during periods of relatively greater aridity in the thar desert and its margins incisions occurred during the wet phases in ois 1 it is inferred that changes in the monsoon precipitation led to relative changes in the discharge and sediment supply which were routed through those in the vegetation cover and played a key role in determining the fluvial style an inter comparison of the late quaternary alluvial deposits in the semi arid regions of western india suggests a continuum of fluvial environments interrelated through a precipitation gradient further a global comparison indicates that the response of semi arid western indian rivers was synchronous with the rivers in other climatic settings

seismic hazard and total risk analyses for large dams in euphrates basin turkey reservoirs constructed near urban areas pose a high risk potential for downstream life and property turkey is one of the most seismically active regions in the world and has at least 1200 large dams with different types major earthquakes with the potential of threatening life and property occur frequently here the euphrates basin studied in this article is located in a seismically very active part of turkey the northern part of the basin is structurally cut by numerous faults many large dams are located on or close to these faults in this paper we summarize the methods used for the analysis of seismic hazards and total risk discuss the seismic hazards of thirty two large dams constructed on the euphrates basin on the basis of the seismic activity of the dam site and their total risk as based on physical properties and the position in the basin the seismic hazard analyses have indicated that peak ground acceleration changes within a wide range 0 011 g and 0 564 g for the dam sites of the basin a seismic hazard map showing the equivalent pga peak ground acceleration values was developed so as to use for the preliminary analysis of dam structures which will be designed in the basin the total risk analyses depending on the seismic hazard rating of dam site and risk rating of the structure have concluded that fifteen large dams have high risk class in the basin these dams must be analyzed with high priority and redesigned to increase the safety of the embankments and their appurtenant structures if necessary

early cenozoic two phase extension and late cenozoic thermal subsidence and inversion of the bohai basin northern china abstract the bohai basin is one of a family of early cenozoic extensional basins that lie along the eastern margin of asia from russia to vietnam initial extension was probably triggered by subduction roll back of the oceanic pacific plate from the asian continent there were two phases in the bohai basin s rift history the earlier paleocene early eocene phase resulted in the deposition of the kongdian formation and the fourth lowest member of the shahejie formation in a series of elongate half grabens these half grabens have master faults with a nne ssw orientation secondary normal faults are typically clockwise oblique to the master faults indicating a component of dextral transtension deposition was focused in the west and south of the present basin these rocks are mainly alluvial fan and fluvial red beds the architecture of the basin underwent an important change at ca 43 45 ma middle eocene beginning with the deposition of the third member of the shahejie formation in part these sediments were deposited in the same half grabens as the kongdian formation but the bozhong depression in the central part of the basin originated at this time and became the major depocentre the bozhong depression superficially resembles a pull apart basin it formed when continued transtension of the earlier tertiary fault systems to the east and west created an extensional overlap between them during this phase the basin as a whole had a geometry with elements typical of both pull apart and transtensional basins regional extension in many east asian basins ended at the end of the oligocene probably because of the onset of transpression within eastern asia caused by the collision of australia with the philippine sea plate dextral transpression caused minor inversion of some of the earlier normal faults in bohai but as a whole the basin began to subside in a post rift phase of thermal subsidence that has lasted until the present day

from mountain source to ocean sink the passage of sediment across an active margin waipaoa sedimentary system new zealand abstract the joint us nz source to sink initiative aims to unravel the tectonic climatic and other processes that shape the landscape from the mountains to deep ocean of two focus areas chosen world wide the waipaoa sedimentary system wss of north eastern new zealand was identified as an example of a mid latitude high sediment input system it resides within the westerly wind belt and extends across the convergence zone of the australian and pacific plates accordingly the tectonic and climatic drivers are prominent and their influences on the wss are decipherable as is documented in the suite of source to sink studies presented in this special issue of marine geology the wss is forced at several temporal and spatial scales which collectively appear as short term events storms earthquakes and volcanic eruptions superimposed on long term behavioural shifts tectonic uplift and eustatic sea level change overall the wss is undergoing uplift which has been contributing to valley incision since the last glacial maximum uplift is both gradual and intermittent the latter relating to fault and subduction related earthquakes such seismic activity destabilises the landscape and together with frequent storms generates large amounts of sediment as this sediment passes through the system part is captured in traps formed by local subsidence of the coastal plain and middle continental shelf where large thicknesses of holocene and probably older sediment are sequestered e g 200 m under the coastal plain nevertheless substantial sediment still reaches the continental slope to accumulate in canyon heads and slope basins with other deposits redistributed down slope in mass flows major volcanic eruptions also affect the sediment flux via direct input from ash fall and by enhanced erosion following volcanic destruction of terrestrial vegetation frequent storms of varying intensity play a key role in the generation and transfer of sediment major events such as cyclone bola of 1988 inundated the shelf with sediment but identifiable flood deposits were preserved only locally attesting to the effectiveness of shelf physical and biological mixing regimes despite the storms earthquakes and volcanic eruptions the largest perturbation of the wss at least in the last 2400 years has been the human deforestation of the landscape the resultant influx of sediment overwhelmed the shelf s storage capacity instead of capturing 90 the fluvial input as in pre human times the modern shelf retains only 25 the remainder escaping to the slope and elsewhere

discrimination of water inrush source and evolution analysis of hydrochemical environment under mining in renlou coal mine anhui province china with the development of mining the hydrochemical environment has changed in the renlou coal mine anhui province china it will be of great significance to coal mine safety production by exploring the temporal and spatial evolution law of hydrochemistry of main water inrush aquifers in renlou coal mine under the effect of mining groundwater samples from three main water inrush aquifers in different periods were collected to analyze their principal components and establish the discrimination model of water inrush source the first and second principal components with eigenvalues greater than 1 were selected in which the first principal component represents sulfate dissolution and pyrite oxidation and the second principal component represents desulfurization and cation alternating adsorption the evolution law of hydrochemical environment was analyzed by combining the distribution characteristics of principal component scores with the spatial location of misjudged groundwater samples the results show that 1 quaternary aquifer is greatly affected by mining and the hydraulic connections with carboniferous limestone aquifer in the central region leads to two misjudged groundwater samples in the discriminant model 2 permian sandstone aquifer is to a certain extent affected by mining which shows a relatively closed hydrogeological environment in most areas of coal mine and an opened environment in some areas with time there are five misjudged samples in the discriminant model due to hydraulic connections with the quaternary aquifer and carboniferous aquifer in some areas 3 carboniferous limestone aquifer is controlled by typical faults and collapse columns and mining has a slight influence on it in the central area there are hydraulic connections with the quaternary aquifer and the permian sandstone aquifer due to the collapse columns which lead to four misjudged groundwater samples in the discriminant model

late quaternary linkage of sedimentary records to three astronomical rhythms and the asian monsoon inferred from a coastal borehole in the south bohai sea china abstract the bohai sea was formed by subsidence during the cenozoic some 2000 3000 m of fluvial lacustrine and marine sediments has been deposited in this basin previous studies focused mainly on the transgression history with little examination of orbital variation in relation to other areas within the asian monsoon domain here we present the late quaternary results of a new borehole in the south bohai sea optically stimulated luminescence and radiocarbon dating which provide concordant age estimates were employed to generate an initial chronology for the borehole after refining the chronology through astronomical tuning the results showed that 1 the grain size variation represents asian monsoon intensity which was dominated by both solar insolation major and global ice volume minor forcing 2 the magnetic susceptibility indicates river incision processes which were sensitive to orbital tilt with influence from solar insolation 3 the vegetation coverage responded to global ice volume coupled obliquity changes and that 4 neither external nor internal factors could dominate the paleoenvironmental evolution on orbital timescales in an independent way and they are both integrated in a complex pattern we conclude that three different astronomical rhythms have affected coastal evolution and that the sedimentary records in the south bohai sea china result from the nonlinear interaction and the complex response to driving processes

analysis of earth dams affected by the 2001 bhuj earthquake an earthquake of magnitude of 7 6 mw 7 6 occurred in bhuj india on january 26 2001 this event inflicted damages of varying extents to a large number of small to moderate size multi zone earth dams in the vicinity of the epicenter some of the distress was due to the liquefaction of saturated alluvium in foundation liquefaction was relatively localized for the majority of these dams because the earthquake struck in the middle of a prolonged dry season when the reservoirs behind these dams were nearly empty and shallow alluvium soils underneath the downstream portions of the dams were partly dry otherwise liquefaction of foundation soils would have been more extensive and damage to these dams more significant six such dams have been examined in this paper four of these facilities chang shivlakha suvi and tapar were within the 50 km of epicenter region these dams underwent free field ground motion with peak ground accelerations between 0 28g to 0 52g of these chang dam underwent severe slumping whereas shivlakha suvi and tapar dams were affected severely especially over the upstream sections fatehgadh dam and kaswati dam were affected relatively less severely foundation conditions underneath these dams were first examined for assessing liquefaction potential a limited amount of subsurface information available from investigations undertaken prior to the earthquake indicates that although the foundation soils within the top 2 0 to 2 5 m underneath these dams were susceptible to liquefaction bhuj earthquake did not trigger liquefaction because of lack of saturation of these layers underneath the downstream portions of these dams these dams were then analyzed using a simple sliding block procedure using appropriate estimates of undrained soil strength parameters the results of this analysis for these structures were found to be in general agreement with the observed deformation patterns

the record of mid holocene maximum landward marine transgression in the west coast of bohai bay china abstract this study used benthic foraminifera diatom total organic carbon organic carbon isotope ratios c n ratios and grain size data from three ams 14 c dated cores collected from the western coastal lowland of bohai bay china to elucidate the coastal response to relative sea level change during the holocene a layer of peaty clay overlaying early holocene terrestrial sediment was dated to 8400 8000 cal bp and the peaty material in the sediment suggests possible vegetation cover before the mid holocene marine inundation in the study area sedimentary facies and changes in diatom and foraminifera assemblages suggest a five stage marine transgression regression history during the first stage from 8000 to 7855 cal bp the study area was inundated primarily by freshwater swamp during the second stage from 7855 to 6000 cal bp the study area was under brackish water influence in the third stage from c 6000 to 5750 cal bp the study area experienced marine influences and by this time the holocene transgression reached its maximum landward location and height this was followed by a period of regression since c 5750 cal bp during the last 4000 years the study area was influenced by freshwater and became a floodplain environment thus this study reveals that the most landward position of the holocene marine transgression was situated somewhere between the coring locations of dc01 and qx01 which is about 80 km inland from the present shoreline this means the west coast of the bay has advanced at an average speed of c 13 m a since the mid holocene the relative sea level around 6000 cal bp was at 2 64 0 1 m

holocene evolution of bottom sediment distribution on the continental shelves of the bohai sea yellow sea and east china sea abstract coastline shifts due to transgression and regression can remodel tidal fields of continental shelves and this can control transport of sediments and modulate sediment distribution accordingly tidal currents have become the dominant hydrodynamic processes on the continental shelves of the bohai sea yellow sea and east china sea byecs since the transgression after the last glacial maximum lgm to examine the evolution of the bottom sediment distributions on the continental shelves of the byecs we simulated patterns of tides and tidal currents sediment transport and bottom sediment types sand mud and mixed sediments for five periods corresponding to sea level lowstands of 80 m 52 m and 30 m below present the holocene transgression maximum htm and the present the simulation shows that both sediment transport and shelf sediment distribution patterns were controlled by the strength type and asymmetry of tidal currents in the byecs since the lgm evolution of shelf sediment distribution patterns occurred in two stages 1 sediment emplacement and formation stage before the htm and 2 local adjustment after the htm the marked changes in coastline configuration since the lgm are the dominant factor controlling tide and tidal current evolution distribution of shelf sediment types in the byecs is closely related to tidal current fields during transgression after the lgm

prediction of water inrush risk areas in process of mining under the unconsolidated and confined aquifer a case study from the qidong coal mine in china the unconsolidated cenozoic formation is well developed in the qidong coal mine water inrushes from the bottom unconsolidated cenozoic aquifer which is the confined aquifer have happened several times during mining in the north mining area of the qidong coal mine to predict the water inrush risk areas in the south mining area of the qidong coal mine where some working faces have just begun to mine the engineering analogy method is used on basis of the fisher s discriminant model from the actual mining situation in the north mining area six main influence factors including the effective thickness the specific yield and the load transfer coefficient of the aquifer the effective thickness of the protective bedrock layer the fractal dimensional value of bedrock faults and the distance between the key hard stratum and the primary mineable coal seam are selected as discriminant indexes and their corresponding data in the north mining area of the qidong coal mine are served as training samples on this basis the fisher s discriminant model for water inrush is established and water inrush risk areas including the safety the medium risk and the risk areas of no 61 82 and 9 primary mineable coal seams in the south mining area of the qidong coal mine are predicted by the model the model s accuracy is 90 4 the scatter diagram of training samples shows obviously classified effect and the field verification indicates that the predicted type is consistent with the actual type results show that the discriminant model is well applied in the engineering analogy method and the water inrush risk areas predicted by the discriminant model contribute to the subsequent mining in the south mining area in the qidong coal mine

pleistocene forced regressions and tidal sand ridges in the east china sea abstract tidal sand ridges are common features on modern shelves but only few examples of such preserved sand bodies are described in pleistocene deposits in the stratigraphic record some sand bodies encased in shales previously interpreted as sand ridges have been reinterpreted as shoreface deposits more than 5000 km of high resolution seismic data from the east china sea correlated to geotechnical boreholes and shallow cores demonstrate the potential of sand ridge preservation and allow reconstruction of the depositional history of pleistocene fourth order 100 kyr depositional sequences a high subsidence rate of about 300 m myr allows the preservation of three elementary sedimentary facies constitutive of a motif which was repeated during glacio eustatic cycles they consist of 1 regressive marine prodeltaic prograding wedges 2 estuarine and continental deltaic facies and 3 transgressive sand ridges similar in shape and orientation to modern sand ridges major discontinuities traceable over the entire outer continental shelf along distances of hundreds of kilometers are transgressive and regressive surfaces of marine erosion whereas sequence boundaries formed by fluvial erosion are difficult to identify on this low gradient shelf because of the asymmetry of the pleistocene glacio eustatic cycles most of the preserved sedimentary record with the exception of sand ridges corresponds to forced regressive deposits deposits that formed during a seaward shift of the shoreline due to relative sea level lowering

characterization of underground tunnel water hydrochemical system and uses through multivariate statistical methods a case study from maddhapara granite mine dinajpur bangladesh a quality study of the drained water from maddhapara granite mine underground tunnel was undertaken to study their hydrochemical variations and suitability for various uses employing chemical analysis basic statistics correlation matrix r cluster analysis principal component factor analyses and anova as the multivariate statistical methods the results of chemical analysis of water show the modest variation in their ionic assemblage among different sampling points of the tunnel where ca hco3 type of hydrochemical facies is principally dominated the correlation matrix shows a very strong to very weak positive even negative correlation relationship suggesting the influence of different processes such as geochemical biochemical processes and multiple anthropogenic sources on controlling the hydrochemical evolution and variations of water in the mine area cluster analysis confirms that cluster 1 contains 68 75 of total samples whereas cluster 2 contains 31 25 on the whole the dominated chemical ions of first cluster groups are ca and hco3 suggesting a natural process similar to dissolution of carbonate minerals the second cluster group consisted of cl and so4 2 ions representing natural and anthropogenic hydrochemical process the results of pca fa analysis illustrate that different processes are involved in controlling the chemical composition of groundwater in the mine area the factor 1 loadings showed that ph ec tds na mg chloride and sulfate which have high loading in this factor are expected to come from carbonate dissolution to oxidation conditions one way anova describes the significance of dependent variables with respect to independent variables anova gives us the idea that ec k fetotal so 4 2 as and pb are the most important factors in controlling spatial differences in water quality in this tunnel but different results have been encountered for different independent variables which might be due to dissimilar sources of water from the qualitative analysis it is clear that water quality is not very favorable for aquatic creatures as well as for drinking purposes the water can be used for irrigation purposes without any doubt as sar and rsc analysis provides good results moreover the results of this research confirmed that the application of multivariate statistical analysis methods is apposite to inferring complex water quality data sets with its possible pollution sources at the end this research recommends 1 as water becomes more and more important water treatment plants should be built before the water being used 2 a detailed water step utilization plan should be set beforehand to guarantee tunnel water being used effectively and 3 after the water being used for agriculture elements in crops should be monitored continuously to ensure that ions and compounds that come from the tunnel water are lower than guideline values for human beings health

multivariate statistical analysis of geochemical data as indicative of the hydrogeochemical evolution of groundwater in a sedimentary rock aquifer system summary the study of groundwater hydrogeochemistry of the paleozoic basses laurentides sedimentary rock aquifer system in quebec produced a large geochemical dataset groundwater samples were collected at 153 sites over a 1500 km2 study area and analyzed for major and minor ions the large number of data can lead to difficulties in the integration interpretation and representation of the results two multivariate statistical methods hierarchical cluster analysis hca and principal components analysis pca were applied to a subgroup of the dataset to evaluate their usefulness to classify the groundwater samples and to identify geochemical processes controlling groundwater geochemistry this subgroup consisted of 144 samples and 14 parameters ca2 mg2 na k hco 3 cl so 4 2 fe2 mn2 br sr2 f ba2 hs seven geochemically distinct clusters c1 c7 resulted from the hca samples from clusters c3 c4 c6 and c7 are mostly located in preferential recharge areas the majority of these samples have ca mg hco3 recharge groundwater c3 c6 c7 and na hco3 evolved groundwater c4 samples from the other three clusters c1 c2 c5 are characteristic of an aquifer system under confined conditions the majority of these samples have na hco3 evolved groundwater c1 c5 and na cl ancient groundwater that exhibits elevated concentrations in br c2 in addition to recognizing the importance of hydrogeological conditions on groundwater geochemistry the distribution of clusters also showed the importance of the geological formations on minor and trace elements such as fe2 mn2 sr2 f and ba2 the first five components of the pca account for 78 3 of the total variance in the dataset component 1 is defined by highly positive loadings in na cl and br and is related to groundwater mixing with champlain sea water and solute diffusion from the marine clay aquitard the high positive loadings in ca2 and mg2 of component 2 suggest the importance of dissolution of carbonate rocks in this aquifer system from their characteristic loadings the first two components are defined as the salinity and hardness components respectively components 3 5 are related to more local and geological effects the integration of the hca and the pca with conventional classification of groundwater types as well as with the hydrogeological and geological contexts allowed the division of the region into four main geochemical areas providing an improved regional picture of the aquifer system dynamics and hydrogeochemical evolution of groundwater the following factors were recognized as influencing the evolution of groundwater identified in every geochemical area 1 geological characteristics including sedimentary rock type and till mineralogy 2 hydrogeological characteristics represented by the level of confinement and the hydraulic gradient and 3 the geological history including the latest glaciation and the champlain sea invasion with its integrated approach this hydrogeochemical study contributes to the characterization and understanding of complex groundwater flow systems and provides an example of the long term geochemical evolution of hydrogeological systems after a major perturbation in this case seawater invasion

a review of wanganui basin new zealand global reference section for shallow marine plio pleistocene 2 5 0 ma cyclostratigraphy abstract wanganui basin new zealand contains one of the most complete late neogene marine stratigraphic records in the world the ca 2 km thick basin fill for the last ca 2 5 ma comprises 47 superposed cyclothems which correspond to successive 5th 100 ka and 6th 41 ka order glacio eustatic sea level fluctuations on the palaeo new zealand shelf since oxygen isotope stage 100 stages 100 to 5 are represented by marine cyclothems whereas stages 17 to 3 are represented by a suite of coeval and younger uplifted marine terrace sequences additionally a predominantly glacial loess stratigraphy exists for isotope stages 12 2 the presence of interbedded tephras and an established paleomagnetic stratigraphy allows the development of an integrated cyclostratigraphy for wanganui basin which correlates closely with the global oxygen isotope scale in all except two cases cycles 12 and 36 individual unconformity bound cyclothems sequences represent a single glacial interglacial couplet of milankovitch frequency lithologic and faunal variation within the cyclothems corresponds closely to that predicted by the sequence stratigraphic model each cyclothem generally contains a transgressive systems tract a mid cycle condensed shellbed a highstand systems tract and often a regressive systems tract six common cyclothem motifs are inferred to represent deposition in shelf locations between the highstand and lowstand shorelines viz the hawera maxwell turakina seafield castlecliff and rangitikei motifs a seventh type the nukumaru motif includes coquina limestone and represents deposition in shoreface and very shallow water marine environments

the bhuj india earthquake lessons learned for earthquake safety of dams on alluvium abstract the bhuj india earthquake of 26 january 2001 m s 7 9 caused dams built on alluvium to sustain damage ranging from cosmetic to severe major damage was caused almost entirely by soil liquefaction in the alluvium the critical factor was the level of earthquake ground motion the bhuj earthquake showed that peak horizontal accelerations phas 0 2 g were generally safe phas 0 2 g were hazardous when unconsolidated granular foundation soils were water saturated n values of 0 2 g must be evaluated over the full area beneath a new dam and all soils deemed susceptible to liquefaction must be either removed or treated for remediating an old dam reliable options are removal and replacement of liquefiable alluvium beneath upstream and downstream portions of the dam combined with building berms designed to provide stability for the dam should there be a strength loss in soils beneath the dam

landslide evolution assessment based on insar and real time monitoring of a large reactivated landslide wenchuan china abstract the upper minjiang catchment is frequently affected by a significant number of large to giant landslides in one such massive older landslide approximately 2 million m3 of sediment was reactivated threatening the safety of a pylon on the landslide and the safety of the only route that allows high speed travel from wenchuan to maoxian to trace the deformation evolution history and analyze the current deformation of the new landslide we examined sar data since 2007 carried out geological and uav surveys and designed and installed real time monitoring equipment this paper presents the main spatial and temporal characteristics of the landslide we found that the landslide has experienced creep deformation in the past five years and its sensitivity to rainfall the development process of the landslide from the formation of tensile crack at the trailing edge to the gradual pushing forward of the crack propagation was revealed the innovation of this paper is to reveal the whole process of the spatial temporal evolution from its beginning to large deformation of a real case of creep landslide which can provide a very good reference for the analysis and monitoring of such creeping landslide evolution process this representative case also shows how to combine remote sensing and in situ monitoring methods to carry out continuous monitoring and the establishment of a warning system for potential landslide sites so as to trace the evolution history derive activity maps and analyze development trend which can significantly reduce landslide risk additional mitigation procedures can be put into place if continuous monitoring of the minjiang river canyon occurs resulting in a reduction of direct losses in particular modeling of the slope deformation and failure damming process and prospective flooding can be done in advance therefore it is expected that this report can strengthen the case for the deployment of systematic monitoring of potential landslide sites by integrating earth observation methods and in situ monitoring systems as an approach to reduce risk

plio pleistocene ice volume antarctic climate and the global δ18o record we propose that from 3 to 1 million years ago ice volume changes occurred in both the northern and southern hemispheres each controlled by local summer insolation because earth9s orbital precession is out of phase between hemispheres 23 000 year changes in ice volume in each hemisphere cancel out in globally integrated proxies such as ocean 18 o or sea level leaving the in phase obliquity 41 000 years component of insolation to dominate those records only a modest ice mass change in antarctica is required to effectively cancel out a much larger northern ice volume signal at the mid pleistocene transition we propose that marine based ice sheet margins replaced terrestrial ice margins around the perimeter of east antarctica resulting in a shift to in phase behavior of northern and southern ice sheets as well as the strengthening of 23 000 year cyclicity in the marine 18 o record

hydrochemical signatures of deep groundwater circulation in a part of the himalayan foreland basin groundwater samples were analyzed from 71 springs and wells as part of a larger study in a region of compressional tectonic regime the study site covers the peshawar basin and surroundings in the himalayan foreland of pakistan the northern portion is mountainous and the water table is discontinuous in different intermontane valleys with abundant springs with normal and anomalous temperatures and composition the southern part is divided into isolated basins with a number of drilled deep and dug shallow wells hydrochemical signatures of elevated strontium sr sio2 boron b and the geothermometric signatures all indicate a deep circulation of the emerging groundwater moreover for several of the sample sites water chemical compositions measured spring and water well temperatures and reservoir temperatures calculated for spring waters all point to origin from deep horizons within the basin remarkable proximity of all the thermal and hydrochemical anomalies to major faults suggests that the waters ascended along these faults from greater depths the area is a natural western extension of the himalayan geothermal belt described in earlier literature for the eastern and central himalayas

thermal history and tectonic subsidence of the bohai basin northern china a cenozoic rifted and local pull apart basin the bohai basin is a part of the larger bohai bay basin a cenozoic rifted intraplate basin heat flow measurements show that the bohai basin is characterized by present day heat flow varying between 53 and 74 mw m 2 with a mean of 63 mw m 2 however thermal history analyses derived from vitrinite reflectance vr and apatite fission track aft data indicate that tertiary cooling took place following a period of much higher paleo heat flow 70 90 mw m 2 prior to 25 million years to the present furthermore tectonic subsidence analysis reveals that the bohai basin experienced episodic sub rifting processes from the eocene to the end of the oligocene the post rift thermal subsidence was superimposed by intensified subsidence from the late miocene 12 million years in the bozhong depression and from the early quaternary 2 4 million years in the east liao bay indicating a rejuvenation of sedimentation related likely to transpressional structures developed locally on strike slip faults the present results indicate that there is good agreement between the reconstructed thermal history and the timing of the tectonic subsidence stages within the bohai basin the bohai basin is an early cenozoic rifted and local pull apart sub basin of the larger bohai bay basin 2001 elsevier science b v all rights reserved

the factors controlling vertical color variations of north atlantic madeira abyssal plain sediments abstract colors of madeira abyssal plain sediments north east atlantic were determined with a simple colorimeter and described in the second cie 1976 color space l a b color space l a b values of the original sediment core and the powdered sediments vary sharply with depth and these variations were found to be due to changes in the contents of calcium carbonate organic matter iron and manganese the vertical color profiles are essentially conserved after drying and powdering these results suggest that this rapid measurement method with the colorimeter can be used in quantitative color determination of marine sediments aboardship as a result of quantitative studies among l a b values calcium carbonate organic carbon iron and manganese contents of powdered sediment samples the following conclusions were obtained 1 l value psychometric lightness is controlled by calcium carbonate for whitish color and by organic matter for blackish color the redox fronts can be easily characterized by a sharp decrease in l value 2 a value psychometric red green chromaticness is controlled by iron for pelagic sediments by manganese carbonate and iron oxide and hydroxide for calcareous turbidites and turbidite g and by pigments and iron ii bearing minerals for greenish and grayish turbidites 3 b value psychometric yellow blue chromaticness is controlled by iron contents probably in the form of hydroxides for calcareous turbidites

study of multi aquifer groundwater interaction in a coal mining area in china using stable isotopes and major ion chemical data investigations have been undertaken to determine the interactions between the main aquifers in a coal mining area near the taihang mountains in china to determine the sources of water environmental isotopes 18o 2h 3h 34s and water chemistry ions ca2 mg2 na k hco3 so42 cl were used as tracers furthermore batch sampling and testing were conducted on mountain spring water and karst water in the aquifers of the taiyuan group fengfeng group and majiagou group on the seatearth of the coal mining area via field observations and laboratory experimental analysis the 18o and 2h values of the mountain spring water and karst water in the coal mining area showed a common distribution with the local meteoric water line el1 of karst water in the majiagou group but significantly deviated from the surface water evaporation line el2 in the coal mining area when combined with the distribution of karst water level values thus karst water in the coal mining area is mainly supplied by groundwater from mountainous areas furthermore the concentration of sulfate ions increased dramatically in the groundwater flow of karst water from mountain spring water to karst water in the fengfeng group and majiagou group of the coal mining area when equivalent concentrations of ca2 mg2 hco3 and so42 hco3 reached their peak the chemical type of groundwater gradually evolved from ca mg hco3 to ca mg so4 hco3 in addition significant positive correlation was found between the 34s and so42 values of the water samples indicating that gypsum is involved in groundwater lixiviation in contrast the relationships of ca na versus mg na na hco3 versus total dissolved solids tds and na versus cl revealed that tds and salinity accumulate from the mountain spring water and karst water in the taiyuan group of the coal mining area furthermore the chemical type of groundwater gradually evolved from ca mg hco3 to na hco3 as revealed by a piper trilinear diagram

iron reduction through the tan green color transition in deep sea sediments mossbauer spectroscopic investigations of deep sea sediments from the peru basin revealed a prominent downcore increase of the bulk sediment fe ii fe iii ratio across the well known tan green color transition this increase occurs along a continuous gradient extending over a 3 cm zone at the two deep sea sites that we report remarkably constant values of the fe ii fe iii ratios above 11 2 89 2 and below 37 2 63 2 the iron redox transition zone delimit the gradient clearly a minor peak of diagenetic iron enrichment is manifest at the redox front this fe enrichment has accumulated in a redox cycle and amounts to 16 4 of the total fe at the peak maximum the data imply that 26 4 of the detrital iron has experienced in situ redox transition from fe iii to fe ii within the iron redox transition zone

summer monsoon variations over the last 1 2 ma from the weathering of loess soil sequences in china the loess soil sequence in northern china contains a near continuous record of quaternary paleoclimate magnetic susceptibility and grain size have so far been the only proxies available to address the long term changes of the east asian paleomonsoon extending back to more than one million years in this study the ratio of cbd citrate bicarbonate dithionite extractable free fe2o3 fed a measure of iron liberated by chemical weathering versus the total fe2o3 available fet was measured on samples at 10 cm intervals taken from two loess sections deposited over the last 1 2 ma variations of this index are highly consistent with other pedological indicators but in addition provide a quantitative measurement of the degree of pedogenesis in the loess plateau since chemical weathering in the region mainly depends upon summer precipitation and temperature weathering intensity primarily reflects changes in the east asian summer monsoon the new proxy has been used to document a series of summer monsoon changes of global significance which are not necessarily recorded by magnetic susceptibility

sequence stratigraphy of sixth order 41 k y pliocene pleistocene cyclothems wanganui basin new zealand a case for the regressive systems tract this study is based on a late pliocene and early pleistocene approximately 2 6 1 7 ma succession about 1 km thick of 20 sixth order 41 k y duration cyclothems of shelf origin exposed in the rangitikei river valley in the eastern part of wanganui basin the cyclothems correlate with 18 o isotope stages 100 58 and each 41 k y glacialinterglacial stage couplet is represented by an individual depositional sequence comprising transgressive highstand and regressive systems tracts unlike most examples inferred from the stratigraphic record these systems tracts were deposited during phases of known sea level cycles indicated by the contemporary oxygen isotope ice volume curve because of the high rate of subsidence of wanganui basin glacioeustatic sea level falls during most cycles were not of sufficient magnitude to expose the outer shelf thus the rangitikei section provides an exceptional example of regressive strata deposited landward of the contemporary shelf break simple one dimensional modeling shows that moderate to high rates of basin subsidence 1 2 mm yr and low rates of sedimentation 0 2 mm yr during transgressions combined to produce an accommodation surplus at the relative highstand this surplus accommodation was infilled during the late highstand and ensuing fall partly by aggradational highstand systems tract shelf siltstone and chiefly by strongly progradational shoreface sediments of the regressive systems tract rangitikei regressive systems tracts are distinguished from forced regressive systems tracts sensu hunt and tucker 1992 by their different stratal geometry by definition forced regressive systems tracts display an erosional contact with the underlying highstand systems tracts and typically occur as a series of downstepped disjunct shoreline wedges stranded on the shelf and or slope in contrast regressive systems tracts exhibit a gradational lower contact above which parasequences are stacked in a strongly progradational pattern terminated by the superjacent sequence boundary cyclothems display two types of motif termed rangitikei dt depositional transgression and rangitikei nt nondepositional transgression which include the following architectural elements in ascending stratigraphic order 1 a basal sequence boundary that is coincident with either the transgressive surface of erosion which displays small scale up to 50 cm erosional relief and may be penetrated by the ichnofossil ophiomorpha or its deeper water correlative conformity 2 either a thick 5 30 m transgressive systems tract comprising a deepening upward nearshore to inner shelf mixed carbonate siliciclastic lithofacies succession depositional transgression or a thin 2 m transgressive systems tract comprising condensed fossiliferous facies deposited on the sediment starved offshore shelf nondepositional transgression 3 a sharp downlap surface separating condensed fossiliferous facies of the transgressive systems tract from terrigenous siltstone of the superjacent highstand systems tract 4 a highstand systems tract comprising a 10 20 m thick interval of aggradational shelf siltstone and 5 a thick up to 45 m progradational inner shelf to shoreface lithofacies assemblage ascribed to the regressive systems tract condensed shell beds are associated with intrasequence and sequence bounding discontinuities and together with the sedimentological and stratal characteristics of the sequences are important indicators of stratigraphic architecture four types of shell bed are associated with surfaces formed by four different types of stratal termination onlap backlap downlap and flooding surface shell beds cf kidwell 1991 are associated respectively with the transgressive surface of erosion apparent truncation at the top of the transgressive systems tract the downlap surface and local marine flooding surfaces a fifth shell bed type termed a compound shell bed forms in offshore environments where the downlap surface converges with the sequence boundary and elements of both the downlap and the backlap shell beds become mixed or superposed the shell beds mark zones of stratal attenuation and can be used as surrogates for seismic discontinuities when applying sequence stratigraphic concepts at outcrop scale

monsoon climate of the early holocene climate experiment with the earth s orbital parameters for 9000 years ago values for the precession and obliquity of the earth 9000 years ago indicate that the global average solar radiation for july 9000 years ago was 7 percent greater than at present when the estimated solar radiation values are used in a low resulation climate model the model simulates an intensified continent scale monsoon circulation this result agrees with paleoclimatic evidence from africa arabia and india that monsoon rains were stronger between 10 000 and 5000 years ago than they are today

sea level and deep sea temperature variability over the past 5 3 million years ice volume and hence sea level and deep sea temperature are key measures of global climate change sea level has been documented using several independent methods over the past 0 5 million years myr older periods however lack such independent validation all existing records are related to deep sea oxygen isotope 18o data that are influenced by processes unrelated to sea level for deep sea temperature only one continuous high resolution mg ca based record exists with related sea level estimates spanning the past 1 5 myr here we present a novel sea level reconstruction with associated estimates of deep sea temperature which independently validates the previous 0 1 5 myr reconstruction and extends it back to 5 3 myr ago we find that deep sea temperature and sea level generally decreased through time but distinctly out of synchrony which is remarkable given the importance of ice albedo feedbacks on the radiative forcing of climate in particular we observe a large temporal offset during the onset of plio pleistocene ice ages between a marked cooling step at 2 73 myr ago and the first major glaciation at 2 15 myr ago last we tentatively infer that ice sheets may have grown largest during glacials with more modest reductions in deep sea temperature a novel approach to the estimation of sea level and deep sea temperature has been used to determine these quantities over the past 5 3 million years this approach based on oxygen isotope records from the eastern mediterranean shows that temperature and sea level histories are broadly correlated but also show intriguing temporal offsets most records of past sea level variation and associated changes in ocean temperature rely on variations in oxygen isotopes recorded in deep sea marine microorganisms these signals unfortunately are confounded by other influences making it difficult to extract a clear climate related signal eelco rohling and colleagues now present a novel approach to estimating sea level and deep sea temperature variations for the past 5 3 million years the record based on oxygen isotope variations from the eastern mediterranean avoids the issues of the deep sea approach and generally corresponds to an independent record of the past 1 6 million years as expected temperature and sea level are broadly correlated but also show intriguing temporal discontinuities as at the initiation of plio pleistocene ice ages when a major sea level drop lagged a sharp temperature decline by several hundred thousand years

assessment of the impact of anthropogenic activities on the groundwater hydrology and chemistry in tarsus coastal plain mersin se turkey using fuzzy clustering multivariate statistics and gis techniques summary tarsus coastal plain tcp is an economically and ecologically important area situated in between the fertile fluvio deltaic plains of two rivers delicay and tarsus mersin se turkey where anthropogenic activities agricultural industrial and domestic are very intense twenty four water quality parameters were surveyed at 193 groundwater and 10 surface water sites during august 2008 the objective was to characterize the physico chemical properties of groundwaters in tcp assess the impact of anthropogenic activities on the groundwater hydrology and chemistry and identify the major hydrogeochemical processes occurring in the area groundwater samples were grouped into hydrochemically distinct and spatially continuous four water classes i e c1 c2 c3 and c4 using the fuzzy c means fcm clustering method where membership values were interpolated using the ordinary kriging technique principal components analysis pca was used to decipher various underlying natural and anthropogenic processes creating these distinct water classes four principal components pcs were extracted in pca which explained more than 73 of the total variance in water quality major factors responsible for the variations in chemistries of water classes are identified as 1 water rock interaction and nitrate contamination 2 salinization by seawater intrusion and evaporite dissolution 3 geogenic anthropogenic cr fe and mn and 4 anthropogenic zn pollution overexploitation of the aquifer is clearly evident especially at settlements located near the coastal zone where the water table is lowered 2 5 m below the sea level salinization is well known in the area and is attributed not only to seawater intrusion but also to dissolution of evaporitic series from the handere formation hydrochemical evidence also suggest that in the area subsurface paleo river channels and the deposits infilling the ancient lagoon area within quaternary recent alluvial deposits act as significant hydrological features where preferential groundwater flow occurs along them

preliminary study of the dynamic origin of the distribution pattern of bottom sediments on the continental shelves of the bohai sea yellow sea and east china sea the bottom sediment types in the bohai sea yellow sea and east china sea byecs are diversified and their distribution pattern is very complicated however the bottom sediment types can be simplified to be sandy sediment clayey sediment and mixed sediment which comprise the complicated distribution pattern of bottom sediment in the byecs the continental shelves of the byecs are broad with shallow water depths and tidal currents which are permanent and dominate the marine dynamics in the byecs based on numerical simulation of tidal elevations and currents in the byecs the rates of suspended load transport and bed load transport during a single tidal cycle for sediments of eight different grain size ranges are calculated the results show that any sediment whose threshold velocity is less than that of tidal current has the same transport trend suspended load transport rare bed load transport rate and the ratio of the former to the latter decrease with grain size becoming coarser and coarser the erosion accretion patterns of sediments with different grain sizes are determined by the sediment transport rate divergences and the results show that the patterns are the same for sediments with different grain sizes three main bottom sediment types i e sandy sediment mainly composed of fine sand clayey sediment mainly composed of silty clay and mixed sediment mainly composed of fine sand silt and clay are obtained by computation the three bottom sediment types and their distribution pattern are consistent not only with sediment transport field and the sea bed erosion accretion pattern obtained by simulation but also with field data of bottom sediment types and divisions in the byecs sand ridges form mainly in the areas with strong rectilinear tidal currents sand sheets form mainly in the areas dominated by strong rotatory tidal currents and clayey sediments i e mud patches form mainly in the areas with weak tidal currents hence not only the sandy sediments but also the clayey sediments in the byecs are formed under the control of the whole tidal current field of the byecs the three main bottom sediment types are not isolated respectively in fact they constitute a whole tidal depositional system under the condition with no cyclonic cold eddy the clayey sediments in the byecs can form in weak tidal current environments therefore a cold eddy is not necessary for the deposition of clayey sediments in the byecs c 2000 academic press

sedimentary history of the western bohai coastal plain since the late pliocene implications on tectonic climatic and sea level changes abstract thick cenozoic deposits from the western bohai coastal plain a tectonic subsiding region provide the potential to study the relations between sedimentary environments and tectonic climatic and sea level changes however sedimentary history of this region extending to the whole quaternary as well as their links to tectonic climatic and sea level changes are still poorly understood mainly because of the lack of long term records with well constrained chronology in this study we present an integrated record based on sedimentology and proxies grain size and color reflectance of a 203 6 m core recovered from the western bohai coastal plain near tianjin the core was chronologically well constrained using paleomagnetic and optically stimulated luminescence dating methods the results show that from the late pliocene 3 3 ma to the late pleistocene 0 10 ma the study region was mainly dominated by fluvial setting and the extensive incursion of sea water into this region began during the last interglacial period 0 10 ma the sedimentology and the color index suggest that tectonic subsidence of the bohai basin during the plio quaternary must have played a significant role in controlling the sedimentary environments in this region the changes in base level because of sea level fluctuations during the quaternary influenced the fluvial development greatly and led to the alternations of coarse crevasse splay channel and finer floodplain deposits in the core sequence in addition climatic changes since the late pliocene also have had significant effects on the sedimentary settings in the bohai coastal plain by influencing the fluvial process with a series of mechanisms

tidal deposition systems of china s continental shelf with special reference to the eastern bohai sea abstract the continental shelf of china has undergone a large scale marine transgression tidal currents have become the main active agent and have had a profound influence on the deposition and geomorphology of the shelf the continental shelf of china has five modern tidal deposition systems 1 the eastern part of the yellow sea 2 the eastern part of the bohai sea 3 off the mouth of yangtze river 4 to the west of taiwan and 5 the strait of qiongzhou when the tidal current speed is above 150 cm s erosion dominates and reciprocating currents form deep scour furrows when the tidal current speed is 50 to 150 cm s deposition is dominant and tidal currents form tidal shoals i e tidal sand ridges and tidal sand sheets whose margins are near an absolute ellipticity value for the m2 tidal component of 0 4 when the absolute m2 value is less than 0 4 a reciprocating current is strong enough to form tidal sand ridges when the absolute value is above 0 4 a rotating current increases so as to form a tidal sand sheet tidal deposition material came mainly from tidal erosion and locally redeposition of late pleistocene sediments and from the neighbouring sea bottom the tidal deposition system in the eastern bohai sea is a typical example it consists of the laotieshan channel scour furrow the liaodong shoal sand ridges and the bozhong shoal sand sheet the maximum tidal current speed in the laotieshan channel where strong erosion occurs is up to 250 cm s in the liaodong shoal the maximum tidal current speed is 64 115 cm s and the absolute ellipticity value of the m2 tidal component is less than 0 4 in the bozhong shoal the maximum tidal speed is 58 79 cm s and the absolute ellipticity value of the m2 tidal component is above 0 4 the small scale bedforms surveyed in detail in the area show that the sand ridges and sand sheet are still under the action of tidal current processes at the present time based on the interpretation of tidal currents bedforms and sediment thickness it is inferred that the general direction of sediment transport within the study area is nnw from the laotieshan channel to the liaodong and bozhong shoals the small scale bedforms in the detailed survey area indicate a local net sediment transport from south to north

late quaternary evolution of the yellow east china sea tidal regime and its impacts on sediments dispersal and seafloor morphology the evolution of a tidal current field in the yellow sea and east china sea yecs in response to the sea level rise since the last glacial maximum lgm was investigated using a two dimensional tidal model with special attention to changes in the sedimentary environment of the continental shelf region it was found that tidal currents on the yecs shelf have generally been semi diurnal throughout the post glacial stages with f ratio index of diurnal inequality and s2 m2 ratio index of spring neap cycle remaining similar to present on the other hand the spatial distribution of the tidal bottom stress associated with m2 and m4 tidal currents changed greatly during the transgression as the sea level rose two core regions showing high bottom stress values migrated shoreward from cheju island toward the west coast of korea and along the retreat path of the paleo changjiang estuary distribution of extremely intense tidal bottom stress suggested that intense tidal reworking may have occurred at sea levels from 90 to 45 m in the southeast yellow sea and at 75 to 60 m off the paleo changjiang estuary the latter of which agreed with the timing of a large terrigenous organic c flux observed on the shelf slope distribution of slightly weaker bottom stress indicated that the sand ridges off the changjiang estuary and in the southeast yellow sea also might have formed at during those periods on the other hand when the sea level was between 45 and 15 m the tidal bottom stress was generally not strong enough to invoke significant reworking even though the stress intensity may be stronger than present correlation with modern and relict sedimentary features suggested that the tidal process have played a significant role on the reworking and deposition of sediments on the yecs shelf

paleomagnetic and astronomical dating of sediment core bh08 from the bohai sea china implications for glacial interglacial sedimentation abstract sediments from the continental shelf coastal region bear significant signals of sea level climate change as well as local tectonic information this study presents a high resolution magnetostratigraphic and rock magnetic study of a 212 4 m core bh08 with a basal age of 1 06 ma recovered from the shallow 18 o records at 40 and 100 kyr cycles indicating that the sediments in the study area are continuous at least at orbital timescales regardless of significant base level variations this is likely due to continued subsidence in the basin and creation of accommodation space the significant lower sedimentary accumulation rates since 750 ka might be due to the deviation of the depositional locus from core site because of extreme low sea level stands during the glacials since the mid pleistocene transition mpt especially the glacial sea level lowstands might have resulted in bypassing or erosion of sediments on the bh08 core site during peak glacials mis 6 mis 10 and mis 16 limiting the sediment preservation potential this study documents the longest quaternary sedimentary succession in the bohai sea and provides for the first time a clear link between sedimentation in the area and glacial interglacial climate driven sea level changes this study also highlights the feasibility of astronomical tuning to obtain high resolution chronology for shallow shelf deposits which is otherwise very difficult to be achieved on the basis of magnetostratigraphic data alone

pedogenesis of late quaternary deposits northern kyonggi bay korea implications for relative sea level change and regional stratigraphic correlation abstract late pleistocene and early holocene paleosols are described from construction pits and boreholes in the northern kyonggi bay west coast of korea thin section petrography chemistry clay mineralogy and geotechnical properties of the paleosols were examined to infer relative sea level fluctuations during the late quaternary relict laminae and gradational contacts with underlying tidal rhythmites confirm that the late pleistocene paleosol is a pedogenically altered tidal deposit illuvial clay coatings rootlets and enrichment of kaolinite and chemically stable oxides indicate that pedogenesis occurred on a well drained stable surface during the last glacial period redoximorphic features such as drab colored root traces and sphaerosiderite however suggest that waterlogged conditions developed temporarily due to a rise of the water table at the end of the last glacial period as sea level rose an early holocene paleosol formed in freshwater bog deposits burying the late pleistocene paleosol the early holocene paleosol has abundant sphaerosiderites and organic material the presence of weakly developed illuvial clay coatings oxidized siderites and pellets however indicates oxidizing condition associated with water table fall occurred during the early holocene despite the similarity in the degree of chemical and clay mineralogical weathering the late pleistocene paleosol is distinguished from its early holocene counterpart by thicker and more abundant illuvial clay coatings more fe 2 o 3 and a greater degree of consolidation duration of pedogenesis might be a primary cause for the difference of the pedofeatures with climate playing a secondary role the widespread presence of similar late pleistocene paleosols highlights its significance as a key stratigraphic marker for regional correlations along the west coast of korea

multivariate statistical analysis of water chemistry in evaluating groundwater geochemical evolution and aquifer connectivity near a large coal mine anhui china major ion chemistry of groundwater from main aquifers near the dingi coal mine anhui china was analyzed with a suite of statistical techniques in an effort to understand aquifer connectivity and groundwater geochemical evolution fifty seven groundwater samples were analyzed from four aquifers the cenozoic top middle bottom aquifers and a permian coal strata aquifer with increasing depth of the aquifers groundwater became more mineralized showing greater hardness and salinity the dissolutions of halite and sylvite carbonate sulfate and silicate minerals were the primary processes controlling groundwater chemical compositions in the cenozoic bottom and coal strata aquifers while k na and hco3 originating from silicate mineral weathering were more enriched in the coal strata aquifer principal component analysis pca identified two principal components with the first component representing hardness variation and accounting for 57 5 of total variance and the second component 23 5 of total variance controlled primarily by salinity and sulfate reduction process the cenozoic bottom aquifer had greater hardness than other aquifers whereas the coal strata aquifer was characterized by higher salinity and larger influences of sulfate reduction cluster analysis revealed that the coal strata aquifer was largely isolated from the cenozoic aquifers with possible infiltration at discrete locations indicating that the high yield thick cenozoic aquifers may serve as a potential additional source for groundwater inrush into coal mines

plio pleistocene vegetation changes in the north china plain magnetostratigraphy oxygen and carbon isotopic composition of pedogenic carbonates abstract the plio pleistocene history of c4 plant biomass in northwestern china has been documented from the loess soil sequences of the loess plateau region however how c4 plants evolved in the warmer and low elevation eastern china monsoon zone is still poorly known mainly because of the unavailability of well dated geological records in this study a 203 6 m core of floodplain deposits was recovered from the north china plain near tianjin and dated magnetostratigraphically the results define a chronosequence for the last 3 3 ma the late quaternary portion of the core consists of fluvio marine sediments while the rest of the section 3 3 0 6 ma contains abundant paleosols formed on the floodplain as confirmed by soil micromorphological evidence the stable carbon and oxygen isotopic composition of pedogenic carbonates was measured to document vegetation and climate changes the results reveal mixed c3 and c4 vegetation with an estimated c4 abundance of 40 60 from 3 1 to 2 2 ma and a subsequent gradual decline to 25 until 0 6 ma this trend is consistent with the data from the loess soil sequences further west on the loess plateau suggesting they are regionally significant changes the lowering of growing season temperature and or drier conditions induced by global cooling would explain this overall decline

dda validation of the mobility of earthquake induced landslides abstract this paper studies the run out of earthquake induced landslides there are more than 20 mechanical models to explain long run out of rapid landslides including some earthquake induced landslides however notably few of them considered the effect of seismic loading on the run out of landslides in a previous study we have proposed a model which is called the multiplex acceleration model mam to interpret the long run out mechanism and a shaking table test has been performed to verify the mam because the previous mam is a conceptual model and only a single stone has been examined under sine waves by the shaking table test the mam needs to be extended and further verified in this paper the mam was extended by introducing the movement change that was induced by the so called trampoline effect of earthquake loading and the latest practical numerical simulation program discontinuous deformation analysis dda was used to verify the mobility of earthquake induced landslides after a conceptual landslide model was used to verify the effect of seismic loading on the mobility the donghekou landslide which was a typical long run out landslide that was induced by the 2008 wenchuan earthquake was analyzed the results show that the seismic loading could be one of the factors that could eventually help increase the run out of landslides

stratigraphic development during the late pleistocene and holocene offshore of the yellow river delta bohai sea abstract a 61 m long sediment core hb 1 and 690 km of high resolution seismic profiles from offshore of the yellow river delta bohai sea were analyzed to document the stratigraphy and sea level changes during the late pleistocene and holocene accelerator mass spectrometry 14c dating and analyses of benthic foraminifera ostracods the mineral composition and sedimentary characteristics were performed for core hb 1 and seven depositional units du 1 du 7 in descending order were identified the seismic reflection data were interpreted in light of the sedimentological data of the core and correlated with other well studied cores obtained previously in the bohai sea area seven seismic units su 1 to su 7 in descending order were distinguished and interpreted as follows su 7 corresponds to marine facies in marine isotopic stage mis 5 su 6 to terrestrial facies in mis 4 su 5 and su 4 to alternating terrestrial and marine facies du 7 du 5 in mis 3 su 3 to terrestrial facies du 4 in mis 2 su 2 to holocene marine facies du 3 and du 2 and su 1 to modern yellow river delta sediments deposited since 1855 du 1 the sedimentary facies from du 7 to du 5 reflect sea level fluctuations during mis 3 and the boundary between du 5 and du 6 which coincides with that between su 4 and su 5 is a distinctive laterally continuous undulating erosion surface with up to 20 m of relief this surface reflects subaerial exposure between transgressions during mis 3 estimated sea levels during mis 3 ranged from 35 5 to 60 5 m or lower with short term fluctuations of 20 m sedimentary environments in the bohai sea area were governed mainly by eustatic sea level changes and the bohai strait topography which controls the entry of sea water into the bohai sea area the mineral composition of the sediment core suggests that the yellow river did not discharge into the bohai sea or at least did not influence the study area significantly during parts of mis 3 and mis 2 to the early holocene 11 8 5 cal kyr bp

total risk rating and stability analysis of embankment dams in the kachchh region gujarat india a method for total risk analysis of embankment dams under earthquake conditions is discussed and applied to the selected embankment dams i e chang tapar rudramata and kaswati located in the kachchh region of gujarat india to obtain the seismic hazard rating of the dam site and the risk rating of the structures based on the results of the total risk analysis of the dams coupled non linear dynamic numerical analyses of the dam sections are performed using acceleration time history record of the bhuj india earthquake as well as five other major earthquakes recorded worldwide the objective of doing so is to perform the numerical analysis of the dams for the range of amplitude frequency content and time duration of input motions the deformations calculated from the numerical analyses are also compared with other approaches available in literature viz makdisi and seed 1978 approach jansen s approach 1990 swaisgood s method 1995 bureau s method 1997 singh et al approach 2007 and saygili and rathje approach 2008 and the results are utilized to foresee the stability of dams in future earthquake scenario c 2010 elsevier b v all rights reserved

milankovitch scale multi proxy records from fluvial sediments of the last 2 6 ma pannonian basin hungary abstract the continuous cores of two nearly 500 m deep boreholes cutting pleistocene fluvial sequences in the eastern part of the pannonian basin hungary have been studied magnetostratigraphy indicates that the sediment sequences span the last 2 6 ma without significant hiatuses comparison of systematic variations in magnetic susceptibility with changes in grain size distribution revealed milankovitch scale cyclicity in sedimentation of 40 and 100 kyr cyclicity which also shows a correspondence with the 18o variations of the odp 677 site comparison of pollen and gastropod paleoecological data with the magnetic susceptibility proxies suggests that climate was a major allogenic control on the cyclicity zones of high magnetic susceptibility correspond closely with sandy and coarse silty parts of the borehole successions which largely coincide with pollen and molluscs indicating a warm climate on the contrary zones with low magnetic susceptibility correspond to silts and clays and in most cases coincide with cold climate indicator pollen and molluscs heavy mineral and xrd studies revealed that magnetic susceptibility reflects the absolute amount of detrital fe oxide minerals mostly magnetite variations in the amount of magnetite are related to changes in heavy mineral content which arise primarily from changes in sediment supply to the basin by rivers the depositional model for the pleistocene fluvial sediments suggests that sediment flux increased towards the basin during interglacials due to the increased discharge and transport capacity of the rivers while a decreased sediment supply to the distal parts of the basin occurred during glacials a delay between erosion and storage of weathering products near to the source area and subsequent transportation and re deposition of sediments in the basin interior setting is an important cause of this effect