recently growing subaqueous flowstones occurrence petrography and growth conditions abstract subaqueous flowstones have been studied in two resurgence caves in slovak karst southern slovakia namely krasnohorska and drienovska caves the flowstones litter streambeds within the distance of several hundred meters upstream from resurgences they form laminated crusts within channels of the underground streams flowing through the caves layers composed of columnar sparry calcite alternate with those composed of microcrystalline calcite the latter are enriched in fine detrital non carbonate components which resulted in crystallization of microcrystalline calcite instead of sparry calcite the growth rate of the studied flowstones reaches 0 96 mg cm 2 day which corresponds to ca 0 3 mm per year seasonal observations conducted between november 2010 and september 2012 reveal that deposition of subaqueous flowstones in the studied caves significantly depends on the local hydrological conditions during the periods of low flow si calc values of underground stream increase and columnar sparry calcite grows conversely during peak flow periods si calc values decrease and subaqueous flowstones are subjected to destruction both by mechanical erosion and corrosion the decreasing discharge just after peak flows causes deposition of fine grained particles which results in precipitation of microcrystalline layers subaqueous flowstones grow in complete darkness and in atmosphere with elevated co 2 content similarly to typical speleothems but they are fed with turbulent stream water similarly to calcareous tufas their growth rate is higher than those of normal flowstones fed with a film of water seeping down it falls within a range of growth rate of calcareous tufas though near the lower limit of this range therefore subaqueous flowstones represent an intermediate link between other speleothems and tufas deposited outside the cave environment

pore size shape and connectivity in tills and their relationship to deformation processes this paper describes how till bulk porosity and pore shape size and connectivity relate to till deformation processes methods have been developed to examine till pores microscopically using thin section analysis scanning electron microscopy sem and x ray computed micro tomography ct porosity is quantified using digital image analysis of thin section images from the petrographic microscope and sem and from x ray ct these methods were applied to a selection of pleistocene tills with diverse properties the micromorphological techniques have allowed porosity to be related to other till microstructures most of the microstructures examined including the pores have been interpreted to be indicative of either plastic or brittle subglacial deformation and the type and extent of till deformation has been interpreted to affect bulk porosity pore type and pore connectivity

testing a logic tree approach for archaeoseismology to the ancient city of pinara sw turkey geologists seismologists as well as archaeologists increasingly apply archaeoseismological investigations to study possible natural causes of damage of a site and to assess the regional seismic hazard risks archaeoseismological investigations enable the obtaining of diverse data on past earthquakes and allow for an application of different methods furthermore archaeoseismology provides the opportunity to study past earthquakes in regions where limited instrumental and historical data are available therefore this approach contributes to a regional assessment of seismic hazard the increasing application and importance of archaeoseismology requires a comprehensive and systematic approach the logic tree methodology for archaeoseismology is an evaluation method which offers a standard procedure to identify and evaluate archaeoseismological information and to provide comparable values for seismic hazard assessment this study tests the logic tree methodology for archaeoseismology to pinara to assess the city s potential to have recorded earthquakes and the methodology s value the ancient city of pinara sw turkey 500 bc 900 ad is situated in the esen basin in the southern extremity of the seismically active fethiye burdur fault zone the present seismic quiescence of the esen basin contradicts the geological and historical records which indicate that fault and earthquake activity must have been recurrent with the application of the logic tree approach to pinara geological and archaeoseismological evidence of seismic activity is evaluated in six stages the end solution of the logic tree provides a value between 0 and 1 this archaeological quality factor aqf reflects the reliability and relative significance of pinara for archaeoseismological investigation and seismic hazard assessment respectively pinara s preferred end solution pes1 of 0 06 and the aqf of 0 12 are obtained by the logic tree method and reflect the high probability of recorded palaeoearthquakes in pinara in sum the logic tree for archaeoseismology provides a concept with reliable criteria to assess the earthquake hypothesis in general and the findings suggest the assumed low seismic hazard potential of this area needs serious reconsideration 2011 elsevier ltd and inqua

tide and storm surge predictions using finite element model a finite element fe model is used to study tides and hurricane storm surge in the gulf of mexico in the region ranging from the mississippi sound to the northwest coast of florida issues that are emphasized include the use of large domains the importance of a high degree of grid resolution in coastal regions of interest the use of meshes with highly varying nodal densities to minimize the size of the discrete problem and the use of the generalized wave continuity equation gwce for fe based solutions to the shallow water equations the computations presented are unprecedented in their scope level of localized detail and degree of grid size variability the gwce based fe model leads to very accurate and efficient flow solutions

carbonate deposits from the ancient aqueduct of beziers france a high resolution palaeoenvironmental archive for the roman empire abstract carbonate deposits from a roman aqueduct in beziers southern france record environmental conditions during the late first century c e these deposits formed in a steep section of the aqueduct with a high flow velocity which caused rapid deposition of up to 11 mm of calcite per year over a period of 22 24 years the microstructure trace element and stable isotope composition show that regular deposition was interrupted by high discharge events probably in response to heavy rainfall during autumn and winter transporting colloidally and particle bound elements and depositing calcite with elevated 18 o values individual autumn high discharge events coincide with abrupt decreases in 13 c from 8 to 12 giving rise to a saw tooth profile in some years several high flow events persisted throughout the winter suppressing this profile event horizons of micrite capping sparite growth surfaces enriched in mg may represent anomalously low water levels or periods when the channel fell dry in comparison to carbonate deposits from roman aqueducts in the eastern mediterranean visible layering is less regular and pronounced in beziers reflecting a more complex precipitation pattern

mid pleistocene hominin occupation at elandsfontein western cape south africa abstract the current understanding of landscape scale variation in mid pleistocene hominin behavior is limited most of our understanding derives from a few localities in eastern africa consequently we know very little about hominin landscape use outside this region despite the fact that mid pleistocene hominins occupied other climatic zones including temperate and mid latitude ecosystems the winter rainfall zone in south africa represents one of the world s most diverse ecosystems although mammal diversity is relatively low in these habitats this is compensated by the tremendous floral diversity buried pleistocene land surfaces in the region provide an opportunity to understand how humans adapted to this unique mid latitude environment prior to the last interglacial the dunefield locality of elandsfontein in the western cape of south africa is one of the richest known paleontological and archeological sites in southern africa it records details of landscape formation history enabling detailed reconstruction of the ancient environments in this winter rainfall dominated region this dunefield archive allows us to posit the taphonomic history of newly excavated archaeological material and previously collected specimens here we provide initial results from the excavation and geological analysis of the elandsfontein dunefield and provide new insights into the formation history of the archaeological and paleontological deposits this includes indications of multiple pedogenic intervals and groundwater table fluctuations the combination of geological paleontological and archaeological data provides a framework for evaluating how hominins interacted with the unique ecosystems of the cape floral region of south africa during the mid pleistocene

challenges for a cross disciplinary geoarchaeology the intersection between environmental history and geomorphology abstract geoarchaeology is a growing subfield of cross disciplinary research at the intersection between geomorphology environmental history and archaeology this prospective essay does not aim to analyze the nature or evolution of geoarachaeology or to review available techniques and methods instead it addresses challenges exciting challenges confront geoarchaeology in the form of persistent problems that demand satisfactory solutions despite improving skills and innovative technologies drawing from the full record of human history a number of practical issues can be highlighted to explicate these challenges 1 open air archaeological sites are the main object of study for the early to mid pleistocene even though they represent open systems that raise fundamental questions about archaeo taphonomic integrity how were sites buried and then modified by selective preservation horizontal or vertical disturbance and the role of carnivores is it possible to determine the degree to which such sites accurately record prehistoric human behavior prior to the late pleistocene when hearths and living structures lend better definition to occupation surfaces can non primary open air sites also shed light on human activities and environmental history 2 cave sites have long been favored by archaeologists because of the impression that they represent relatively complete and undisturbed archaeostratigraphic sequences but serious problems also exist here in regard to the nature of accumulation and the sources of mineral and biogenic sediments in what were open systems liable to disturbance despite comparatively low energy processes 3 less familiar are urban and other architectural sites where processes of formation and degradation mimic natural sedimentation and erosion such a geoarchaeology can be highly informative for urban processes demographic cycles or the intersection between sites and their surrounding landscapes 4 spatial components of geoarchaeological research need more systematic consideration for locational strategies and with an appreciation that site presence or absence allows a more dynamic modeling of settlement and procurement strategies 5 regional settlement expansion and contraction may also inform on mosaic evolution or pleistocene dispersals including the out of africa hypothesis 5 finally multiple themes connected with environmental degradation during holocene times may open new windows to examine specific problems by objective criteria so contributing to a wider academic discourse about long term trends the interfingering of climatic and land use factors in cause and effect dilemmas or the construction of future scenarios in an era of accelerating planetary change the focus of archaeology is shifting to later ranges of prehistory so that geoarchaeologists now have a mandate to engage more directly with urban spatial and degradation issues this should be met with a broader and more inclusive agenda one that optimizes on expertise with historical geomorphology and environmental history but in collaboration with archaeologists and other social scientists that would sustain a more prominent role for geoarchaeology in the university curriculum

annual trace element variations in a holocene speleothem high resolution secondary ionization mass spectrometry sims analysis along the growth axis of a holocene speleothem from northern scotland reveals high frequency oscillations and longer term trends in mg ca sr ca and ba ca at the scale of the high frequency oscillations mg ca and sr ca display a well defined anticorrelation while sr ca and ba ca are positively correlated imaging of elemental ratios in two dimensions reveals that the high frequency signal is well preserved and laterally continuous across the sample tims 230th ages and annual ultraviolet luminescence banding provide chronological control and demonstrate that the high frequency cyclicity is annual trace element variations in speleothem calcite are a reflection of hydrochemical processes in the unsaturated zone overlying the cave supply effects and partitioning at the water calcite interface mg partitioning between water and calcite is temperature dependent calculations suggest that the annual mg ca oscillations may be caused by seasonal temperature changes however the longer timescale variations in mg ca are too great to be explained by this mechanism seasonal variations in water residence time in the unsaturated zone which reflect effective precipitation provide a more probable explanation for the observed annual oscillations and also explain the inverse relationship between mg ca and sr ca this record suggests that trace elements in speleothems have the potential to provide the high resolution insights into interannual palaeoclimatic variability required for assessment of general circulation models

planktonic foraminifera as indicators of oceanographic complexity on the southern caribbean sea continental shelf abstract the southern caribbean sea over the northern south american continental shelf is oceanographically complex it is subject to 1 widespread coastal upwelling 2 wakes and eddies in the nw flowing guiana and caribbean currents to the lee of islands and 3 the hypopycnal orinoco river plume upwelled water is dispersed nw along high productivity filaments offshore northern trinidad an intra plume front separates higher productivity orinoco derived water to the west from lower productivity amazon derived water this paper examines planktonic foraminiferal assemblages in surface sediment samples a below upwelling foci in the gulf of venezuela gov north of lake maracaibo and b at an upwelling focus in the north coast marine area ncma offshore northern trinidad near but west of the intra plume front the samples were collected for previous studies and only certain size fractions which differed between the study areas were available for current study samples from the gov 250 m fraction taken using an alpine corer or a petersen dredge were assigned a priori to groups underlying upwelled and non upwelled water discriminant analysis after cluster analysis confirmed these assignments total recovery was dominated by neogloboquadrina dutertrei with lesser globigerinoides ruberpink and the upwelling indicator globigerina bulloides all four non upwelled samples co dominated by n dutertrei and gs ruberpink reflect seasonal freshwater outflow from lake maracaibo five upwelled area samples were dominated by g bulloides with subdominant n dutertrei or globigerinoides ruber morphotype b the remaining two upwelled samples dominant n dutertrei subdominant gs ruber morphotype a apparently reflect the transition between upwelling and non upwelling areas the mean proportions of assemblages as trilobatus sacculifer morphotype a did not differ markedly between the upwelled and non upwelled gov clusters this morphotype was absent from the gulf proper but present to the north ncma total recovery 150 m fraction samples taken using a van veen grab was dominated by gs ruber morphotype b cluster analysis here indicated three clusters cluster 1 proximal to the intra plume front cluster 2 distal to the intra plume front and cluster 3 scattered throughout the ncma upwelling was pervasive canonical variate analysis cva verifying that g bulloides did not differentiate the clusters instead these clusters were differentiated by gs ruber morphotype b only the proportional abundance of which was highest in cluster i and lowest in cluster 2 this pattern indicates that the influence of the orinoco plume on assemblage composition is stronger than that of upwelling cluster 1 reflecting higher productivity near the front

diagenesis or dire genesis the origin of columnar spar in tufa stromatolites of central greece and the role of chironomid larvae two greek pleistocene tufa stromatolites were examined petrographically and with stable isotope geochemistry to determine whether calcite spar is of primary or diagenetic origin the younger ca 100 ka tufa from zemeno primarily is micritic with primary columnar calcite spar restricted to areas immediately above chironomid larval tubes this relationship suggests that chironomid larval feeding behaviour is responsible for the development of zemeno tufa columnar calcite probably involving biological substances smeared onto the tufa surface most micritic crystals are not suitably oriented to allow later post depositional growth resulting in columnar fabrics the older ca 1 ma predominantly sparry tufa from nemea contains some chironomid tubes and organic cyanobacterial filaments preserved in crystal fans but also contains many fabrics found in primary speleothem spar columnar spar here is unlikely to be the result of post depositional crystal growth a comparison of stable isotopic trends between the two tufa deposits suggests that both contain interpretable seasonal trends and implies little or minor post depositional alteration of either tufa consequently there is no basis for the common assumption that sparry tufa fabrics must be of diagenetic origin

effect of in stream physicochemical processes on the seasonal variations in δ13c and δ18o values in laminated travertine deposits in a mountain stream channel abstract travertines are potential archives of continental paleoclimate records of stable carbon and oxygen isotopic composition 13 c and 18 o in laminated travertine deposits from endogene spring waters show regular cyclic patterns which may be due to seasonal change in climate determinants such as temperature and rainfall in this study 13 c and 18 o measurements of three travertine specimens that grew naturally over the eight years 2004 2011 at upstream middle and downstream sites in a canal at baishuitai sw china are presented they exhibit clear seasonal variations that generally correlate with biannual laminations specifically 13 c and 18 o values show significant positive correlation with each other for the three travertine specimens with the correlation coefficients increasing downstream along the canal to reveal the factors governing the seasonal and spatial variations in 13 c and 18 o values newly formed travertines precipitated on plexiglas substrates are also examined both 13 c and 18 o of the substrate travertines are low in the summer rainy season and high in the winter dry season showing a great consistency with the patterns in the natural travertines spatially isotope values increase downstream in both seasons with higher increase rates in winter that are related to removal of larger fractions of dissolved inorganic carbon dic from the solution and stronger kinetic isotopic fractionation in winter due to in stream physicochemical processes including caco 3 precipitation and the associated degassing of co 2 seasonal changes in 13 c and 18 o in the travertines are amplified by two times between the upstream and downstream sites this is opposite to trends for epigene meteogene tufas whose seasonal changes in stable isotope compositions are reduced downstream we suggest in stream physicochemical processes are a potential reason for underestimation of annual temperature ranges that are inferred from epigene tufa 18 o data

the petrographic and geomechanical properties of some sandstones from the newspaper member of the natal group near durban south africa abstract sandstones are by far the most important rock type in the natal group which is mainly a terrestrial succession formed during ordovician silurian times the most notable member of the group is the newspaper member from which sample material was obtained most of the material sampled was fine to medium grained arkosic sandstone they are well cemented with generally low porosity accordingly sandstones of the newspaper member tend to be very strong and of low deformability few of the petrological properties of these sandstones have a notable influence on the mechanical properties however increasing clay content tends to lower the unconfined compressive strength whilst increasing quartz content tends to enhance it on the other hand many of the mechanical properties are interrelated significant or highly significant relationships occur amongst the strength parameters and between hardness and strength young s modulus also has significant relationships with strength and hardness another property which has a significant influence on strength and deformability is porosity

high resolution records of rainfall events from clay bands in tufa individual rainfall events are recorded as thin clay bands in annually laminated freshwater carbonate tufa runoff from rainfall events entrains clay that then adheres to the tufa surface a specimen collected from southwest japan exhibits 100 clay bands formed during a 15 yr period from 1988 to 2002 the chronology of the clay bands was determined by using the temperature dependent cycle of oxygen isotope ratios in the carbonate and the clay content was quantified by electron probe microanalysis si x ray strength the obtained si x ray strength curve and actual rainfall record follow a nearly identical pattern the clay content of each band correlates with rainfall amount rainfall of 50 mm week produced sufficient amounts of suspended cave clay to produce clay bands in the tufa because the clay bands survive postdepositional alteration this new method can be applied to ancient tufa deposits and has great potential as a high resolution rainfall record for use in climate studies

origins of elements building travertine and tufa new perspectives provided by isotopic and geochemical tracers fluid rock interaction represents a major process in the formation of calcitic or aragonitic travertine and tufa catt in most cases catt is associated to limestone dissolution somewhere along the hydrogeological pathway however a wide array of other substratum basalts rhyolites carbonatites ultramafics granites dolomites evaporites can act as potential source of elements involved in the formation of catt this study reports on the evaluation of potential geochemical tracers linking catt to their substratum and unravelling the origin of elements a large database was established from available literature data as well as new data acquired in the frame of this study for a set of modern to recent catt ligurian ophiolites italy the chaine des puys limagne graben and paris basin france reunion island indian ocean jebel oust tunisia four most reliable tracing methods are identified 1 13c and 18o cross plot allows distinguishing epigean min 13c 27 2 max 13c 0 9 mean 13c 12 3 for n 314 from hypogean systems min 13c 4 max 13c 11 7 mean 13c 2 87 for n 198 very low 13c values 4 associated to negative 13c values are specifically indicative of an ultramafic source rock 2 barium and strontium cross plot helps to discriminate different groups of source rocks amongst the hypogean catt i source rocks composed of mixed limestones evaporites and dolomites are characterised by low barium 400 ppm contents ii mafic and granitic source rocks are undifferentiated and display similar barium from 15 to 930 ppm and high strontium 200 ppm contents iii the carbonatite group is characterised by its exceptional high barium and strontium values in epigean catt a pure limestone source rock usually relates to very low barium and strontium contents 50 ppm 3 relatively high beryllium content 30 ppm in catt seems to indicate a pure granitoid source 4 high chromium concentrations 20 ppm are systematically documented in modern catt located on an ultramafic substratum the definition of diagnostic compositional fields for actively forming or recently formed catt is influenced by many factors including water composition water temperature dissolved gas composition and concentration biological activity position in the sedimentary body and early diagenesis in addition to substratum lithology however the results of this study illustrate that despite these many factors the combined use of ba sr be cr 13c and 18o may be valuable to discriminate the rock lithology prevailing in the hydrogeological or palaeo hydrogeological reservoir of catt

laminated carbonate deposits in roman aqueducts origin processes and implications carbonate deposits in roman aqueducts of patara and aspendos southern turkey were studied to analyse the nature of their regular layering optical microscopy and electron backscattered diffraction results show an alternation of dense coarsely crystalline translucent laminae composed of bundles and fans of elongate calcite crystals with their c axes parallel to the long axis and porous fine grained laminae with crystals at near random orientation the 18o and 13c data show a strong cyclicity and anti correlation whereby high and low 18o values correspond to dense columnar and porous fine grained laminae respectively geochemical analyses show similar cyclic changes in carbonate composition electron microprobe and laser ablation inductively coupled mass spectrometry analyses show that porous fine grained laminae are enriched in elements associated with detrital material fe mg k al and si whereas the dense columnar laminae are nearly pure calcite the gradient in major and trace element distribution regular changes in crystal type and in oxygen and carbon isotope composition from porous fine grained to dense columnar laminae reflect changes in water chemistry discharge temperature and biological activity because of the strong bimodal cyclicity of the mediterranean climate in southern turkey the observed laminae can be attributed to calcite deposition during the dry porous fine grained and wet season dense columnar respectively this observation implies that with proper geochemical and microstructural control lamination in carbonate deposits in roman aqueducts can be used for relative dating of aqueduct construction and maintenance and to obtain data on external factors that influenced the aqueducts such as palaeoclimate and natural hazards carbonate deposits in roman aqueducts show properties of both flowstone speleothems and riverine fresh water tufa as many aqueducts of nearly identical channel geometry are present in different climate zones and with different source water characteristics they can be used as natural experiment setups to test and improve existing models of how laminated fresh water carbonates record climate on time scales ranging from seasonal to millennial

the role of gypsum and or dolomite dissolution in tufa precipitation lessons from the hydrochemistry of a carbonate sulphate karst system the precipitation of freshwater carbonates tufa along karstic rivers is enhanced by degassing of carbon dioxide co2 downstream of karstic springs however in most karstic springs co2 degassing is not enough to force the precipitation of tufa sediments little is known about the role of dissolution of gypsum or dolomite in the hydrochemistry of these systems and how this affects the formation of tufa deposits here we present a monitoring study conducted over a year in trabaque river spain the river has typical karst hydrological dynamics with water sinking upstream and re emerging downstream of the canyon mixing of calcium magnesium bicarbonate and calcium sulphate waters downstream of the sink enhances the dissolution of carbonates and potentially plays a positive role in the formation of tufa sediments however due to the common ion effect dissolution of dolomite and or gypsum causes precipitation of underground calcite cements as part of the incongruent dissolution of dolomite dedolomitization process which limits the precipitation of tufa sediments current precipitation of tufa is scant compared to previous holocene tufa deposits which likely precipitated from solutions with higher saturation indexes of calcite sicc values than nowadays limited incongruent dissolution of dolomite dedolomitization favours higher sicc values this circumstance occurs when waters with relatively high supersaturation of dolomite and low so42 composition sink in the upper sector of the canyon in such a scenario the process of mixing waters enhances the exclusive dissolution of limestones preventing the precipitation of calcite within the aquifer and favouring the increase of sicc values downstream of the springs such conditions were recorded during periods of high water level of the aquifers and during floods this research shows that the common ion effect caused by the dissolution of gypsum and or dolomite rocks can limit or favour the precipitation of tufa sediments depending on the occurrence or not of incongruent dissolution of dolomite dedolomitization copyright 2016 john wiley sons ltd

origin of annual laminations in tufa deposits southwest japan abstract laminated tufas and a tufa depositing stream in sw japan shirokawa ehime prefecture were studied monthly over a 3 yr period a series of samples from the tufa clearly reveals the pattern of annual laminations the annual layering pattern was primarily controlled by changes in the rate of calcite precipitation as calculated from water chemistry the concentration of dissolved caco 3 which correlates with the precipitation rate was high in summer autumn and low in winter spring owing to changes in the partial pressure of co 2 in underground air regular seasonal changes in underground pco 2 probably resulted from two temperature dependent processes the diffusion of soil co 2 and the ventilation of underground air these changes in addition to water temperature changes altered the precipitation rate which has a clear seasonal pattern especially in the lower stream the seasonal precipitation rate was high in summer autumn and low in winter spring which is consistent with the seasonal lamination pattern seen in the tufas the textures of collected samples show that the laminations consist of densely calcified summer autumn june october laminae and lightly calcified winter spring november may laminae we infer that the increased precipitation rate stimulated thick calcite encrustation on cyanobacterial filaments to produce the dense textures this interpretation is supported by the lowered organic inorganic carbon production ratio in summer autumn seasonal variations in cyanobacterial assemblages are present but do not reflect the seasonal lamination pattern because the relevant processes are temperature dependent the seasonal lamination pattern at shirokawa is thought to generally apply to other laminated tufas deposited in temperate climates however a reversed pattern can result from local and climatic circumstances dense laminae were deposited in winter near the source of the spring at shirokawa because calcite precipitation was high owing to low underground pco 2 in winter reversed patterns reported from northwestern europe were probably influenced by seasonal rainfall which is reflected in hydrological conditions

are light dark coupled laminae in lacustrine shale seasonally controlled a case study using astronomical tuning from 42 2 to 45 4 ma in the dongying depression bohai bay basin eastern china abstract as a typical sedimentary structure in fine grained rocks laminae are widely distributed in shales and mudstones in sedimentary basins the shahejie formation 42 2 45 4 ma formed during the eocene of the paleogene in the dongying depression of china is recognized as a typical area to study lacustrine shale according to the composition of different lamina four types of couplets are identified including carbonate clay couplets carbonate organic couplets clay organic couplets and carbonate clay organic triplets all couplets are composed of light and dark layers a combination of core images microscopic observations mineral compositions geochemical data carbon and oxygen isotopes and strontium isotopes verifies that the laminae are primarily developed in a saline and anoxic or even euxinic environment with a high organic matter om flux through astronomical cycle analysis of the natural gamma ray gr curve from sample site well ny1 the data suggest that the lacustrine shale laminae are formed annually with an average duration of 1 34 yr the formation of laminae is affected by the season which is closely related to the seasonal growth and death of algae during the period of algae growth a large number of light colored carbonate laminae are deposited whereas when the algae dies organic matter accumulates at the bottom of lakes and forms dark organic rich laminae the interbedded and lenticular laminae which are subdivided by layering characteristics are primarily affected by diagenesis in postdepositional processes study of the laminae is helpful in understanding the formation process of lacustrine shale and it provides invaluable sources of information for paleoclimate reconstruction

cyclic variations of uranium concentrations and oxygen isotopes in tufa from the middle miocene barstow formation mojave desert california uranium concentrations of 42 to 169 ppm in fibrous calcite from spring deposited tufa in the middle miocene barstow formation california are among the highest reported for calcite fission track maps of multiple bands of uniformly dull luminescent fibrous calcite show that the concentration of u increases in the outward growth direction of the calcite of each individual band homogeneous dull luminescence in the fibrous calcite indicates no change in redox conditions of the fluid from which the calcite was precipitated it is proposed that the cyclic pattern of increase in u concentration reflects a cyclical change in the u ca ratio in the fluid episodic mixing between ca rich spring water with a low u ca ratio and ca poor saline alkaline lake water with a high u ca ratio could produce the episodes of formation of fibrous calcite with increasing u concentrations the spring water supplies the ca for calcite precipitation and the u concentrations increase with the decreasing fraction of spring water and increasing fraction of lake water these cycles reflect a variable recharge of groundwater into the lake by springs the large variation in u concentrations suggests mixing of 0 to 45 spring water with the lake while the narrow range in 18 o of 6 37 to 6 87 limits the variation of the proportions of spring and lake water to 5

mass transport between a semienclosed basin and the ocean maracaibo system 1 field data and three dimensional numerical estuary and lake computer model simulations are used to investigate exchange between lake maracaibo and the gulf of venezuela this exchange occurs along a dredged shipping lane 100 km long and 14 m deep it is driven by a density difference between the lake and gulf and modulated at tidal and subtidal timescales by water level fluctuations in the gulf propagating to the lake at tidal frequencies exchange is modulated by barotropic forcing and nonlinear baroclinic response leading to a severance of high salinity bottom water into seaward and landward segments bottom water in the landward segment is moved lakeward along the shipping lane where it is mixed vertically and flushed out subtidal water level fluctuations in the gulf force barotropic currents along the shipping lane dominating variability of volume and salt flux at timescales of 1 4 weeks the barotropic component of simulated salt flux decreases from the gulf to the lake as depth averaged salinity decreases while simulated baroclinic exchange is only 20 of that predicted by quasi steady two layer hydraulic theory these reductions in salt flux are due to intense mixing that occurs throughout the shipping lane

interaction of ocean tides through a narrow single strait and narrow multiple straits abstract the tidal interaction between two constant depth oceans joined by a rectangular strait of length d width 2a and constant depth h was analyzed the strait is narrow in the sense that the scale of the ocean tide in the absence of the strait is much greater than the width of the straight the following results were obtained i under the mild restriction that the strait is narrow enough sea level tidal constants change linearly from one end to the other if the tides in each ocean differ steep sea level gradients occur in the strait these gradients tend to be much steeper than those in the ocean near the strait ii the steep sea level gradients in the strait drive strong along strait currents which are uniform in the middle part of the strait but change considerably within 0 4a of the ends iii because of end effects strong gradients in sea level can occur across the strait even when the width of the strait is much smaller than the strait barotropic radius of deformation iv when the tid

oxygen isotope composition of annually banded modern and mid holocene travertine and evidence of paleomonsoon floods grand canyon arizona usa abstract holocene and modern travertine formed in spring fed havasu creek of the grand canyon arizona was studied to determine the factors governing its oxygen isotope composition analysis of substrate grown travertine indicates that calculated calcite formation temperatures compare favorably with measured water temperatures and include silt rich laminae deposited by monsoon driven floods ancient spring pool travertine is dated by u series at 7380 110 yr and consists of 14 travertine silt couplets of probable annual deposition one hundred eighty high resolution 18o analyses of this mid holocene sample average 11 0 pdb the average value for modern travertine is 0 5 lower perhaps because mid holocene temperature was higher or there was proportionally greater summer recharge 18o cyclicity in the mid holocene travertine has average amplitude of 1 9 0 5 pdb slightly less than the inferred modern day annual temperature range of havasu creek the annual temperature range might have been reduced during the 14 yr interval compared to present although other non temperature factors could account for the muted annual variation silt rich laminae within isotopically lower calcite in the modern and mid holocene travertine verifies the seasonal resolution of both samples and suggests that similar temperature precipitation conditions as well as monsoon generated summer floods prevailed in the mid holocene as they do throughout the grand canyon region today

a three dimensional model of the northwest european continental shelf with application to the m4 tide abstract the solution of the fully nonlinear three dimensional hydrodynamic equations in polar coordinates for tides is developed using a finite difference grid in the horizontal and the galerkin method in the vertical using this method a three dimensional model of the northwest european continental shelf is used to investigate the spatial distribution of the m4 tidal elevations and currants over the shelf computed m4 currents are compared with observations and found to he in good agreement in the celtic sea although there are significant errors in the north sea the reasons for these discrepancies and the spatial and depth variations in the m4 currants are discussed in detail

mineralogical analysis and provenancing of ancient ceramics using automated sem eds analysis qemscan a pilot study on lb i pottery from akrotiri thera a wide range of existing mineralogical and geochemical methodologies such as optical microscopy x ray diffraction manual scanning electron microscopy icp ms and inaa have been utilised in the analysis of ancient ceramics in attempts to elucidate patterns of regional trade and interaction however advances in automated scanning electron microscopy with linked energy dispersive spectrometers sem eds have created the potential to offer a seamless combination of textural and mineralogical data based on the acquisition of energy dispersive spectra that has so far been unattainable with existing techniques in this pilot study on pottery from the cycladic bronze age site of akrotiri thera we have quantified the mineralogy of the ceramics based on automated sem eds using qemscan technology and imaged the textures of the ceramics through compositional mapping thirteen samples were analysed and based upon the automated analysis four groups of ceramic compositions are defined these data are consistent with but also refine previous traditional petrographic examination of the ceramic samples and enable the likely provenance of the raw materials used in the ceramic manufacture to be identified this technique allows the acquisition of fully quantitative data not only for the larger inclusions within the ceramics but also for the typically finer grained groundmass matrix whilst also providing the overall texture of the ceramic

freshwater phytoherm reefs the role of biofilms and their bearing on marine reef cementation abstract bioconstructions in carbonate rich freshwater environments generally lead to the development of thick autochthonous tufa deposits in rivers systems these large plant dominated freshwater reef frameworks phytoherms are capable of damming the water courses to produce chains of lakes the resulting phytoherms profoundly modify both local environment and sedimentation patterns in their vicinity and provide a wide range of niches for biota subaqueous fringe cements coat all exposed surfaces they bind the ephemeral plant frameworks providing a cement framework and give rigidity to the bioconstructions peloids are intimately associated with the development of these cements and frequently infil intra reef and framework cavities evidence is presented to suggest that both micritic fringe cements and peloids are the product of biological mediation associated with a procaryote microphyte biofilm and the presence of organic detritus the bladed low magnesium calcite fringes which develop subsequently on the micrite fringes and peloids are possibly slower formed inorganic precipitates the close morphological similarities between phytoherm fringe cements and peloids and their marine reef counterparts are considered to be more than coincidental it is argued that procaryote microphyte biofilms are also responsible for micritic precipitates in the shallow photic marine realm with bacterial films possibly carrying the process deep into unlit reef cavities and conduits and deep water lithoherms

a question of scales studying neolithic subsistence using micro ct scanning of midden deposits we tested whether micro ct scanning could be used to study phytoliths and bone fragments on samples from a middle neolithic midden deposit from swifterbant the netherlands we scanned an untreated block sample and an impregnated sample that was used to make a thin section of ample small bones or bone fragments could be discerned and identified most of them from fish although sieving showed that many went undetected it was possible however to identify several deposition events within a few cm of stratigraphy and distinguish deposits with cleaning refuse from bones that were discarded during or after meals bone fragments embedded in coprolitic material represented the ingested and excreted bone fragments moreover it proved to be possible to identify articulated bones or bone fragments that would become separated and unidentifiable during sieving and to recognize specific decay patterns silica phytoliths could be discerned but the resolution was not enough to use it for species identification overall the greatest advantage of microct scanning of undisturbed samples form archaeological sites seem to lie in non destructively providing context and taphonomical information on which further sample treatment and analyses including microsampling and micromorphology can be based

environmental and depositional controls on laminated freshwater carbonates an example from the roman aqueduct of patara turkey abstract carbonate deposits in aqueducts are a new high resolution data source for environmental changes during the time of the roman empire notably in the fields of palaeoclimate and spring hydrology in order to distinguish environmental effects from those related to depositional setting laminated carbonate deposits were compared along the entire length of an ancient aqueduct channel at patara turkey the carbonate deposits up to 80 mm in thickness are composed of lamina couplets up to 1 mm thick of alternating porous microspar and dense columnar sparite the former formed in the dry warm season and the latter in the wet cool season the presence of biofilms seems to play a role in the development of the porous laminae the relative importance of both lamina types depends also on the location within the aqueduct dense coarse crystalline laminae dominate in steep sections of the aqueduct while porous fine crystalline laminae are mostly found on gentle slopes this is attributed to the flow velocity of the water since fast flow on steep slopes hampers the development of biofilms carbonate microstructures can vary considerably down the line of a specific aqueduct hence multiple sampling is needed along the channel in order to collect specimens suitable for detailed research 18 o profiles show oscillations with increasing amplitude downstream reflecting rising water temperatures in the channel while evaporation plays a minor damping role on these oscillations the periodicity of the 18 o values can be used to recognise annual layering in order to establish the number of years an aqueduct was operating 13 c values are higher in open masonry channel sections than in ceramic pipes probably due to stronger degassing of co 2 in the open channel carbonate deposits in roman aqueducts hold high promises as seasonally resolved archives of hydrology and climate and possibly of earthquakes

visualising scales of process multi scalar geoarchaeological investigations of microstratigraphy and diagenesis at hominin bearing sites in south african karst multi scalar geoarchaeological investigations were conducted on several samples of sediment dolomite cave sediments ferricrete ridge speleothem tufa and tufa cave sediments from four early hominin fossil bearing sites taung type site haasgat drimolen main quarry elandsfontein in different south african karst environments the study was designed to test the value of geoarchaeological techniques for identifying and characterising environments of deposition and diagenetic processes involved in site formation within different mediums and different karst environments the traditional petrographic method is weighed against two relatively new methodological contributions to site formation and diagenesis computed tomography ct and automated quantitative evaluation of minerals using energy dispersive spectroscopy qem eds employing qemscan technology an integrated micro sampling approach is outlined for successful cross correlation between techniques the study demonstrates that different analyses vary in their ability to visualise different types of process primary and secondary thin section petrography remains the gold standard for analyses conducted at the micro scale while qem eds and ct offer exciting potential to perform meso scale analyses and are best utilised as complementary rather than alternative techniques to petrography

tidal dynamics in a coupled ocean lake system abstract barotropic tides were studied in the lake maracaibo system venezuela the system consists of two larger water bodies the gulf of venezuela and lake maracaibo connected by the strait of maracaibo and tablazo bay the dominant semi diurnal tide resonates in the gulf and co oscillates roughly 180 out of phase in the lake the narrow strait and shallow bay regulate their dynamical interaction two and three dimensional finite element models are used in conjunction with a fresh analysis of tidal data at seven stations several of which lie in the strait and bay a coupled model of the whole system is necessary to properly interpret these data which show the influence of small scale near field effects superimposed on the larger scale dynamics of the gulf and lake the detailed geometry at the connections with the gulf and the lake also plays a significant role in the local response in the strait and bay co tidal charts are presented for nine major astronomical and shallow water tidal constituents found in the data the velocity structure derived under simple eddy viscosity assumptions is shown to be highly dynamic a characteristic phase lead is found in velocities at depth and near the shore where vertical shear dominates over inertia in the force balance

tides of the caribbean sea analysis of tidal characteristics from 45 gauge locations indicates that the caribbean sea has a microtidal range for the most part between 10 and 20 cm the tide is primarily either mixed semidiurnal or mixed diurnal but a substantial section from puerto rico to venezuela experiences diurnal tides empirical charts of six component tides m sub 2 s sub 2 n sub 2 k sub 1 o sub 1 and p sub 1 show local detail of phase and amplitude each of the semidiurnal component tides is characterized by anticlockwise rotating amphidromes centered in the eastern caribbean there is evidence of strong radiational forcing of the s sub 2 tide in the south western caribbean the diurnal component tides are largely uniform in both phase and amplitude for most of the western and central caribbean however the diurnal phases increase rapidly towards the northwest and the yucatan channel

unmasking the 1349 earthquake source southern italy paleoseismological and archaeoseismological indications from the aquae iuliae fault abstract the 9th september 1349 earthquake was one of the most catastrophic events experienced along the apennines at least three main shocks struck a vast area of the molise latium abruzzi regions and damage was even sustained by the distant monumental buildings of rome the southern most shock mw 6 7 occurred at the border between southern latium and western molise razing to the ground the towns of isernia venafro and cassino amongst others and devastating montecassino abbey as with other medieval catastrophic sequences e g in december 1456 mw 6 5 7 0 this earthquake has not yet been associated to any seismogenic source thus it still represents a thorn in the flesh of earthquake geologists we have here carried out a reappraisal of the effects of this earthquake and through an interpretation of aerial photographs and a field survey we have carried out paleoseismological analyses across a poorly known n130 normal fault that crosses the molise campania border this structure showed repeated surface ruptures during the late holocene the last one of which fits excellently with the 1349 event both in terms of the dating and the rupture dimension on the other hand archaeoseismic analyses have also indicated the faulting of an augustean aqueduct the amount of apparent offset of the aqueduct across the fault traces shows that there were other surface faulting event s during the roman high middle age period therefore in trying to ascertain whether these events were associated with known potentially of 346 ad or 848 ad or unknown earthquakes in the area it became possible that this 20 km long fault here named the aquae iuliae fault is characterized by high slip rates and a short recurrence time this is in agreement with both the similar behaviour of the neighbouring northern matese fault system and with recent gps analyses showing unexpectedly high extension rates in this area

integrated geoarchaeological methods for the determination of site activity areas a study of a viking age house in reykjavik iceland for over a decade geoarchaeological methods such as multi element analysis and soil micromorphology have been used to identify and interpret activity areas on archaeological sites however these techniques along with others such as magnetic susceptibility loss on ignition and microrefuse artefact and bone distribution analyses are rarely integrated in the study of a single site even though they provide very different and potentially complementary data this paper presents a comparative study of a wide range of geoarchaeological methods that were applied to the floors sediments of a viking age house at the site of a alstraeti 16 in central reykjavik iceland along with more traditional artefact and bone distribution analyses and a spatial study of floor layer boundaries and features in the building in this study the spatial distributions of artefacts and bones could only be understood in the light of the ph distributions and on their own they provided limited insight into the use of space in the building each of the sediment analyses provided unique and valuable information about possible activity areas with soil micromorphology proving to have the greatest interpretive power on its own however the interpretation potential of the geochemical methods was dramatically enhanced if they were integrated into a multi method dataset

annual to sub annual resolution of multiple trace element trends in speleothems this study aims to establish evidence for the widespread existence of preserved high resolution trace element variations in speleothems that may have climatic significance ion microprobe analysis of speleothems reveals that annual to sub annual variations in element chemistry exist at five shallow western european cave sites crag cave county kerry and ballynamintra county waterford ireland uamh an tartair sutherland scotland grotte pere noel belgium grotta di ernesto ne italy with widely varying climatic geomorphic and geological settings the variations are not restricted to species mg sr and ba known to substitute directly for ca in the calcite lattice but include h f na and p phosphorus as phosphate displays the greatest variability and may have the most significance as a proxy for the seasonal temperature cycle because of its role as a nutrient element the technique allows estimation of growth rate of speleothems at any interval of interest which is one of several possible uses in palaeoclimatology

normal fault displacement dislocating a roman aqueduct of ephesos western turkey a 38 km long ancient aqueduct channel that served roman ephesos turkey was dislocated vertically over 3 m by a single seismic event on a normal fault a new channel was constructed downstream from the fault in roman times next to and partly on top of the original channel archaeological investigations and study of carbonate deposits suggest a causative seismic event in the second half of the second century ce probably in 178 ce after the original channel had functioned for 35 years the icme tepe fault was identified as responsible for the displacement and may still constitute a seismic and tsunami hazard for the turkish west coast specifically for the city of kusadasi ancient aqueducts of which more than 1400 are presently known are a promising and almost untapped archive for archaeoseismic studies especially in the mediterranean area

evidence for 830 years of seismic quiescence from palaeoseismology archaeoseismology and historical seismicity along the dead sea fault in syria an edited version of this paper was published in earth and planetary science letters by elsevier science elsevier science retains the copyright to this paper copyright 2003 see also http dx doi org 10 1016 s0012 821x 03 00144 4 http atlas geo cornell edu deadsea publications meghraoui2003 epsl htm

climatic significance of seasonal trace element and stable isotope variations in a modern freshwater tufa abstract we present a continuous 14 yr long 1985 to 1999 high resolution record of trace element mg sr ba u and stable isotope 13c 18o variations in a modern freshwater tufa from northwestern queensland australia by utilizing the temperature dependence of the 18o signal an accurate chronology was developed for the sampled profile which allowed a comparison of the chemical records with hydrological and meteorological observations as a consequence it was possible to constrain the relevant geochemical processes relating climate variables such as temperature and precipitation to their chemical proxies in the tufa record temperatures calculated from the mg concentrations of the tufa samples provide close approximations of average annual water temperature variations furthermore we demonstrate that temporal changes in mg ca water can be estimated using an empirically derived equation relating mg ca water to the sr ba ratio measured in the tufa samples by means of this relationship it is theoretically possible to determine the mg ca ratio of paleowaters and hence to derive reliable estimates of former water temperatures from the mg concentrations of fossil tufas from the study area sympathetic variations in sr ba and 13c along the sampled profile record changes in water chemistry which are most probably caused by variable amounts of calcite precipitation within the vadose zone of the karst aquifer this process is thought to be markedly subdued whenever the amount of wet season precipitation exceeds a given threshold accordingly distinct minima in sr ba and 13c are interpreted to reflect years with above average rainfall the pronounced seasonal and annual variability of the u concentration along the profile is thought to primarily record changes in the u flux from the soil to the water table we suggest that during intensive rain events u is transported to the phreatic zone by complexing organic colloids giving rise to conspicuous u maxima in the tufa after above average wet seasons this study demonstrates the potential of freshwater tufas to provide valuable information on seasonal temperature and rainfall variations if tufa deposits turn out to be reasonably resistant to secondary processes combined investigation of speleothems and tufas from the same area could become a promising approach in future research while speleothems offer continuous records of long term paleoenvironmental changes tufas could provide high resolution time windows into selected periods of the past

abiotic versus biotic controls on the development of the fairmont hot springs carbonate deposit british columbia canada the relict fairmont hot springs deposit formed largely of carbonates covers an area of 0ae 5k m 2 and is up to 16 m thick the triangle shaped discharge apron which broadens down valley is divided into a proximal part with beds dipping at 10 and a distal part with beds dipping at 10 to 15 the deposit is formed of the 1 basal macrophyte 2 lower carbonate 3 middle clastic 4 upper carbonate and 5 upper clastic sequences two charcoal samples embedded in the lower carbonate sequence yielded dates of 8690 90 and 8270 70 cal yr bp indicating that much of the deposit formed post glacially during the early to mid holocene deposit aggradation ceased in the mid to late holocene when the fairmont creek valley was incised the lower and upper carbonate sequences which are the thickest sequences are composed of nearly equal parts of travertine abiotic and tufa biotic with feather dendrite travertine radiating dendrite travertine and stromatolite tufa dominating competition between calcite precipitation rates and biotic growth rates controlled the distribution of tufa and travertine across the discharge apron calcite and biotic growth rates were controlled largely by flow velocity across the apron which in turn was controlled by topography and regular fluctuations in spring water discharge volume during times of high spring discharge slow sheet flow over the proximal part of the apron promoted stromatolite growth whereas fast turbulent flow on the distal part of the apron induced rapid feather dendrite formation during times of low spring discharge quiescent shallow evaporative pools conducive to radiating dendrite formation formed on the proximal part of the apron whereas slow flow on the distal part promoted stromatolite growth facies with high calcite supersaturation experienced rapid abiotic dendrite growth that precluded most biotic growth

sedimentation of holocene tufa influenced by the neolithic man an example from the sąspowska valley southern poland abstract a complex of inactive tufas the thickness of which reaches 3 5 m was studied in the lowermost segment of the s spowska valley in the krakow upland ojcow national park poland five fluvial tufa barrages were recognized they are composed of moss tufa and stromatolitic tufa accompanied with oncoidal rudstone and detrital tufa interbarrage ponded areas were filled with detrital tufa lutite and subordinately oncoidal rudstone limestone gravel and peat like deposit radiocarbon dates suggest that the tufa formed during subboreal boreal and atlantic time the main difference between the tufa in the s spowska valley and contemporaneous tufas in other valleys of the krakow upland is the higher amount of non carbonate fraction in the former other lower and middle holocene tufas of the krakow upland are composed mainly or exclusively of carbonate fraction the non carbonate fraction in fluviatile tufas in the s spowska valley resulted from erosion of loess cover in the upper part of the catchment the erosion was related to local activity of neolithic flint miners who cleared forest at a local scale dug shafts in loess cover and exploited flints from underlying weathered residuum of jurassic limestone consequently they made copious amounts of loose material available for transport down the valley and subsequent trapping within the tufa depositional system