pyrite mineralization in microbial mats from the mid proterozoic newland formation belt supergroup montana u s a abstract the mid proterozoic newland formation a shale dominated unit of the belt supergroup was deposited in an eastern extension of the belt basin the helena embayment a variety of different shale facies types can be distinguished of particular interest for this study is a shale facies that has been interpreted to be the result of microbial mat growth resulting in carbonaceous shale beds interrupted by storm deposition causing deposition of graded silt mud couplets alternation of carbonaceous beds with silt mud couplets gives these shales a characteristic striped appearance along the basin margins a pyrite rich sub facies of these striped shales is found locally consisting of laminated pyrite beds that alternate with non pyritic silt mud couplets laminated pyrite beds in pyritic striped shales are interpreted as mineralized microbial mats because of wavy crinkly internal laminae and because of the direct association with unmineralized striped shales that contain microbial mat deposits excess iron in pyritic shale horizons was probably supplied by terrestrial runoff in colloidal form iron hydroxides introduced by rivers into basin marginal lagoons flocculated and were then incorporated into microbial mats and reduced to pyrite upon burial

surface water and groundwater contaminations and the resultant hydrochemical evolution in the yongxiu area west of poyang lake china major ion and stable hydrogen and oxygen isotopic compositions were employed in this study of surface water and groundwater contaminations and their impacts on intrinsic hydrochemical evolution in the yongxiu area west of poyang lake south china a total of 36 samples were collected from surface water and groundwater in the study area where water pollution risk is high due to the fertilizer use for farmland and the waste drainage from a nearby silicon industry site the results show that the surface water bodies have been badly polluted and are characterized by low ph values minimum 2 85 and high concentrations of chemical compounds such as cl na nh4 n no3 n and tds groundwater has also been polluted with the similar specific contaminates as both surface water and groundwater may have similar contamination sources and groundwater is recharged from the precipitation infiltration and surface water leakage as indicated by oxygen 18 and deuterium compositions due to the thin unsaturated zone in the area the acidification and the intrusion of contamination further lead to hydrogeochemical reactions and changed hydrochemical type of groundwater from ca mg hco3 to ca mg na cl the data evaluation methods and results of this study could be useful to the water sustainable usage management in this area and other environmental vulnerable areas

identifying the reworking and stratigraphic provenance of bones by exploring multivariate geochemical relationships with the perio spot technique abstract erosional processes often rework materials of different ages into the same sedimentary facies producing time averaged deposits such reworking is common at archaeological sites and researchers must consider the resulting time averaging effects when using natural stratigraphy to situate artifacts and remains in time at scladina cave a neandertal site in belgium we developed a method for identifying reworked facies and the stratigraphic provenance of mammal bones based on their post mortem trace element characteristics and crystallinity we collected sixty two faunal remains from throughout the site s sedimentary sequence and analyzed them for trace element concentrations and crystallinity with laser ablation inductively coupled plasma mass spectrometry and raman spectroscopy our novel approach the perio spot technique quantifies the trace element characteristics and crystallinity from the most diagenetically altered part of a bone with high spatial resolution trace element concentrations rare earth element patterns and crystallinity of perio spots correlate throughout the scladina sedimentary sequence based on stratigraphic trends in bone chemistry and crystallinity we subdivide the scladina sequence into two successive periods of early diagenesis a period of later diagenesis and a transitional period between the early and later diagenesis periods the period boundaries also correspond to major climatic fluctuations identified in the site s stratigraphy by other means e g palynology and heavy mineralogy the stratigraphic provenance of nine cave bear femora support the confinement of reworking to within each of the diagenetic periods the provenance of two indeterminate faunal remains that visually resemble the taphonomic alteration of the scladina neandertal taphonomic proxies suggest that the individual may be significantly older than previously hypothesized evaluating the temporal integrity of exhumed assemblages and the original sedimentary context of bones with our method is thus a valuable addition to archaeological analyses especially beyond the temporal range of radiocarbon dating or in contexts with very low preservation potential of organic materials

pre screening techniques for identification of samples suitable for radiocarbon dating of poorly preserved bones under certain environmental conditions post depositional diagenetic loss of bone collagen can severely reduce the number of bones from a particular archaeological site that are suitable for stable isotopic analysis or radiocarbon dating this study examined nearly 300 bones from 12 archaeological sites across southern england known to yield poor or variable preservation to try to identify one or more pre screening technique s that would indicate suitable collagen preservation for radiocarbon dating the most reliable method was shown to be the percent nitrogen n of whole bone powder which has an 84 chance of successfully predicting whether or not a bone will yield sufficient i e 1 weight collagen for dating

natural and anthropogenic so4 sources in the arno river catchment northern tuscany italy a chemical and isotopic reconnaissance abstract the 34 s isotope signature of aqueous so 4 2 in the main river arno and principal tributaries was investigated along with major ion chemistry in order to check the pollution effects in the water network of a heavily industrialized and densely urbanized catchment extending in tuscany over an area of 8228 km 2 from the apennine ridge to the tyrrhenian sea major towns include florence and pisa analyses are presented for 29 water samples from the arno river and 36 water samples from the tributaries all collected in 1996 1997 during low flow hydrologic conditions samples from the arno are distributed from source to mouth and those from tributaries upstream from the confluence points the arno river solutes consist mainly of ca 2 and hco 3 but the proportions of na cl and so 4 2 increase downstream in keeping with the basically anthropogenic origin of the latter the 34 s so 4 2 signature also increases downstream with the most depleted values in the source zone the seawater ingression into the river is documented by distinctly higher chemical and isotopic parameters at about 13 km from the mouth in general the tributaries behave similarly to the arno for both their chemical and isotopic compositions with increasing 34 s na cl and so 4 2 downstream the 34 s of so 4 2 in natural inputs is estimated to range approximately between 15 and 4 from oxidation of pyrite disseminated in country rocks and between 15 and 23 from dissolution of evaporites whereas the 34 s of anthropogenic so 4 2 should be variable within the range 1 8

hydrogeochemical interpretation of water seepage through a geological barrier at a reservoir boundary a geological barrier such as a mountain ridge surrounding a large reservoir generally plays some part in preventing water leakage from the reservoir but water flows out naturally according to the hydraulic gradient because the reservoir water level is typically higher than that outside the hydrogeological geochemical and isotopic properties of water in the daechung dam area were analysed to characterize the source and the phenomenon of the groundwater flowing through the geological barrier our geochemical analysis showed that the concentrations of anions and cations tended to increase due to the longer residence time of the water as the distance between the sampling site and reservoir increased elevation differences calculated using oxygen and hydrogen isotopes between the highest and lowest sampling sites ranged between 350 and 420 m based on the altitude effect on isotope concentration but the actual difference was only 35 m these results including analysis of the rate of water seepage from the reservoir ca 2 3 to 14 4 of natural recharge indicate the possibility that groundwater in the study area originated from reservoir water that was derived from upstream water and rainfall in the high mountainous area of the upper watershed copyright 2013 john wiley sons ltd

the possible role of benthic microbial mats during the formation of carbonaceous shales in shallow mid proterozoic basins a considerable portion of the upper member of the mid proterozoic newland formation meagher county montana consists of carbonaceous silty shales striped shale facies this type of shale facies is common in proterozoic basins and is host to several major base metal deposits the striped shales were deposited in a subtidal setting basinward of carbonates characterized by cryptalgal laminites mudcracks and flat pebble conglomerates the carbonaceous silty shales are considered remnants of benthic microbial mats irregular internal laminae patterns of particle trapping mechanical deformation during penecontemporaneous soft sediment deformation and filamentous microbiota provide evidence for this interpretation the dolomitic clayey shale contains graded silt clay couplets and these are interpreted as storm layers modern subtidal microbial mats can only survive under special conditions but in the proterozoic it is suggested that benthic microbial mats colonized the shallow seafloor during periods of low sediment input leading to the formation of carbonaceous shales

grotte chauvet ardeche france a natural experiment for bone diagenesis in karstic context abstract this paper assesses the preservation of bones exposed on the floor of chauvet cave these bones are mainly from cave bears they exhibit very variable macroscopic preservation from apparently pristine specimens to those that are decomposing or coated with calcite this site offers a unique opportunity to investigate on a large scale bone diagenesis in a karstic context despite the highest priority put on the preservation of the cave features about one hundred bone fragments from most sectors of the cave could be collected for biogeochemical investigation carbon and nitrogen elemental content were measured and x ray diffraction spectra were established only about one quarter of the specimens yielded collagen that retained its biogenic isotopic signatures bones exhibiting different stages of preservation were not randomly scattered in the cave local environmental conditions seem to have led to different diagenetic pathways widely differing states of preservation were seen in bones of similar age this site provides a good case study of diagenetic process occurring in karstic sites and may be used to better understand diagenesis in less well studied caves

alteration of enamel carbonate environments during fossilization an understanding of enamel diagenesis is necessary to ensure sound isotopic palaeodietary and palaeoenvironmental reconstructions although carbon isotope signals of browsing and grazing herbivores remain distinct in enamel even after millions of years subtle alteration of isotopic signatures does occur to better understand this change we analysed modern and fossil enamel from a number of south african sites using fourier transform infra red spectroscopy our results indicate that while there is little evidence of increased crystallinity in fossil enamel there is a small but significant change in the proportion of carbonate ions occupying hydroxyl and phosphate sites this seems to occur early in the process of fossilization after which there is no noticeable change it is also important to note that the degree of alteration varies significantly within and between sites we suggest that this change results from one or some combination of three mechanisms exogenous carbonate incorporation endogenous carbonate loss and endogenous carbonate reorganization determining which mechanism s contribute to this alteration is important because all three are likely to affect biogenic carbon isotope ratios differently ftir spectroscopy promises to increase our knowledge of diagenesis and in so doing should improve our palaeodietary and palaeoenvironmental reconstructions

feldspar dissolution enhanced porosity in paleoproterozoic shale reservoir facies from the barney creek formation mcarthur basin australia the paleoproterozoic barney creek formation bcf mcarthur basin australia is one of the oldest active hydrocarbon systems on earth with oil and gas shows present within organic rich intervals up to 7 wt total organic carbon we combine bulk geochemical analyses pore space characterization and high resolution electron imaging techniques to characterize the evolution of the bcf pore system with maturity a thermal gradient from the pre oil window 0 48 calc to gas window 1 01 calc shows a progressive change in pore networks with the loss of organic hosted pores dominant in thermally immature samples to porosity increasingly associated with the mineral matrix with thermal maturity precipitation of fine grained high surface area cements reduced porosity within the oil window whereas feldspar and dolomite dissolution and creation of secondary pores increased porosity within the gas window the abundance of feldspar grains up to 50 provided a significant potential for secondary pore formation as well as a source of silica and clay cement this study identifies a first order linkage between the chemically reactive sediments that are key to the reservoir properties in the bcf and a provenance and or weathering intensity conducive to supplying fine grained mineralogically immature sediments during deposition these findings likely apply more broadly to other chemically immature mudrocks typical of precambrian age sediments or phanerozoic settings subject to limited chemical weathering

diagenesis in bone and enamel apatite carbonate the potential of density separation to assess the original composition abstract this paper presents a new approach to the isotopic measurement of diagenetically altered archaeological bone apatite carbonate we describe how the existing differential dissolution method may be combined with a new approach to remove diagenetically reformed material on the basis of its greater specific gravity we show that heavier more diagenetically altered fraction has a higher altered 13 c and also increased crystallinity within one individual in addition we proposed one potential tool to check the validity of bone carbonate by comparing bone collagen enamel carbonate and bone carbonate values of 13 c and radiocarbon content from the same individual in the case of danebury cattle we estimated the biogenic 13 c apa value for dc83 and dc89 although it is still difficult to overcome diagenesis in order to meet the expected value which is shown to be 1 9 dc83 and 3 5 dc89

petrous bone diagenesis a multi analytical approach abstract the discovery of petrous bone as an excellent repository for ancient biomolecules has been a turning point in biomolecular archaeology especially in adna research but excessive and uncontrolled sampling could result in loss of this valuable resource for future research this study reports on the histological optical microscopy physical ftir atr elemental chn and biochemical collagen and dna analysis preservation of 15 human petrous bones spanning from the c 2100 bce to 1850 ce through the combined application of a number of diagenetic parameters general histological index infrared splitting factor carbonate phosphate ratio amide phosphate ratio col wt c n and c n of whole bone and collagen endogenous dna we provide new insights into petrous bone micromorphological characteristics and diagenesis and new evidence to enhance screening practices for adna and collagen analysis

slow rates of degradation of osteocalcin green light for fossil bone protein our claim published in this journal for successful immunodetection of the protein osteocalcin in dinosaur bone has been challenged on the grounds that the findings are inconsistent with the kinetics of decomposition here we show that the close association of osteocalcin to the bone mineral vastly enhances its preservation potential relative to the same protein in aqueous solution we conducted heating experiments 75 95 c of modern bone powder and monitored the survival of three different regions of osteocalcin n terminal his 4 hyp 9 c terminal phe 45 val 49 and the mid region pro 15 glu 31 with monoclonal antibodies extrapolation of our data to 10 c ambient burial temperatures indicates that preservation of the carboxylated mid region in fossil bone cannot be excluded on kinetic grounds clearly in situ sequence analysis will be the only method by which the preservation of fossil macromolecules will be unequivocally established nevertheless our findings demonstrate the importance of mineral association to protein survival as was borne out by an investigation of holocene ca 6 ka bones only in those samples with little recrystallization was the carboxylated mid region well preserved these results imply that the future success of ancient biomolecule research largely depends on our understanding the interaction between these materials and their environment throughout diagenesis

protracted diagenetic alteration of ree contents in fossil bioapatites direct evidence from lu hf isotope systematics abstract fossil bones and teeth are potentially important repository for geochemical proxy data and a target for radiometric dating the concentration of many trace elements in bones and teeth increases by orders of magnitude after death and it is this diagenetic incorporation that forms the basis for several areas of geochemical study the use of bones and teeth in this context relies on two assumptions first that target metal ions are incorporated rapidly after death reflecting a known environmental signal and second that after early incorporation the bone or tooth remains as an essentially closed system resistant to later diagenetic change a wide literature has developed exploring these assumptions but relatively little direct evidence has been used to assess the long term diagenetic stability of trace elements within bones and teeth in this study we use the lu hf isotope system to show that bones and teeth of cretaceous and triassic age from both terrestrial and marine settings experience continued long term diagenetic change most likely through gradual addition of trace elements modelling suggests that diagenetic addition after initial recrystallisation may account for 50 of the total ree content in the sampled bones the extent depending on initial uptake conditions tooth enamel and enameloid may be more resistant to late diagenetic changes but dentine is probably altered to the same extent as bone these results have significant implications for the use of bones and teeth as hosts of chronological palaeoceanographic palaeoenvironmental and taphonomic information particularly in mesozoic and palaeozoic contexts

cathodoluminescence tools provide clues to depositional history in miocene and pliocene mammalian teeth abstract this paper presents the results of a study which used cathodoluminescence cl observations optical images and sem spectra as a tool for assessing diagenetic processes during fossilisation of continental mammalian teeth the study was performed on fossil teeth of large mammals gomphotheriidae rhinocerotidae and hippopotamidae from namibia and from kenya with ages from the lower and middle miocene to pliocene the fossil sites are distinguished by their environmental conditions they include floodplain deposits fluvial deposits of the proto orange river and aeolianite deposits in namibia and fluvio lacustrine deposits of different ages in kenya optical cl provides information about the sites environments and diagenetic processes related to those environments a blue intrinsic luminescence for the aeolianite deposits and purple to yellowish for floodplain or fluvial deposits the cl spectra of these samples show sharp emission bands which are classically related to late recent incorporation of rare earth elements ree substituting in the ca 2 sites high resolution mapping of the distribution of these ree shows a gradient from the enamel interior low concentrations to the outer enamel margin high concentrations

the origin and economic potential of sandstone hosted disseminated pb zn mineralization in pyritic shale horizons of the mid proterozoic newland formation montana usa pyritic shale horizons of the newland formation belt series mid proterozoic show striking similarities to proterozoic pyritic shales elsewhere that are host to major lead zinc deposits such as mt isa and mcarthur river however in contrast to these deposits the pyritic shales of the newland formation contain only minute quantities of lead and zinc elevated concentrations of lead and zinc are only found in pore spaces of intercalated sandstone beds petrographic and geochemical data indicate that pyritic shale deposition and elevated lead zinc concentrations in sandstone beds are unrelated that base metal mineralization is controlled by initial porosity and that iron and base metals were derived from different sources

effect of land use and urbanization on hydrochemistry and contamination of groundwater from taejon area korea abstract taejon metropolitan city located in the central part of south korea has grown and urbanized rapidly the city depends heavily on groundwater as a water resource because of ubiquitous pollution sources the quality and contamination have become important issues for the urban groundwater supply this study has investigated the chemical characteristics and the contamination of groundwater in relation to land use an attempt was made to distinguish anthrophogenic inputs from the influence of natural chemical weathering on the chemical composition of groundwater at taejon groundwater samples collected at 170 locations in the taejon area show very variable chemical composition of groundwater e g electrical conductance ranges from 65 to 1 290 s cm most groundwater is weakly acidic and the groundwater chemistry is more influenced by land use and urbanization than by aquifer rock type most groundwater from green areas and new town residential districts has low electrical conductance and is of ca hco 3 type whereas the chemical composition of groundwater from the old downtown and industrial district is shifted towards a ca cl no 3 so 4 type with high electrical conductance a number of groundwater samples in the urbanized area are contaminated by high nitrate and chlorine and exhibit high hardness the epco 2 that is the co 2 content of a water sample relative to pure water was computed to obtain more insight into the origin of co 2 and bicarbonate in the groundwater the co 2 concentration of groundwater in the urbanized area shows a rough positive relationship with the concentration of major inorganic components the sources of nitrate chlorine and excess co 2 in the groundwater are likely to be municipal wastes of unlined landfill sites leaky latrines and sewage lines chemical data of commercial mineral water from other jurassic granite areas were compared to the chemical composition of the groundwater in the taejon area factor analysis of the chemical data shows that the hco 3 and no 3 concentrations have the highest factor loadings on factor 1 and factor 2 respectively factors 1 and 2 represent major contributions from natural processes and human activities respectively the results of the factor analysis indicate that the levels of ca 2 mg 2 na cl and so 4 2 derive from both pollution sources and natural weathering reactions

nanomechanical properties of modern and fossil bone abstract relatively little is known about how diagenetic processes affect the mechanical properties of mineralized tissues such as vertebrate bones diagenesis can involve the alteration of bone s organic phase mineral phase and structural organization all of which contribute to bone s nanomechanical properties nanoindentation allows submicrometer investigation of alterations in bone properties that occur during diagenesis in this preliminary study the nanomechanical properties modulus and hardness of recent and fossil bone were compared through the use of depth sensing nanoindentation additionally x ray diffraction and density measurements were used to investigate changes in the mineral phase nanoindentation revealed that the basic mechanical anisotropy of modern bone can be preserved in fossil bones going back at least to the early eocene 50 ma as the elastic modulus i e stiffness values measured perpendicular to the long axis of each bone sample were consistently lower than longitudinal values as is the case for modern bones while a general increase in mechanical properties was observed with the geological age of the samples a relatively small increase was seen in fossil bone samples older than the miocene suggesting that mineral infilling is limited by spatial saturation as the modulus approached that of fully dense minerals such as quartz or apatite further evidence for modification of the mineral phase was demonstrated by an increase in crystallinity and density with the geological age of the bone both increased crystallinity and density correlated with increased modulus values suggesting that the size and perfection of the bioapatite crystals contribute to the mechanical properties of the bones rather unexpectedly the early oligocene aged bones demonstrated reduced modulus and hardness values compared to the miocene and eocene samples which we hypothesize to be related to the diagenetic environment specifically the fossil bearing strata at the oligocene aged locality contain volcanic ash which is known to dissolve bone mineral a plausible cause for the decreased mechanical properties of the oligocene bones our study demonstrates that nanoindentation a relatively nondestructive tool is useful in investigating tissue level diagenesis in bone that cannot be seen with the naked eye and can provide insight into the functional significance of mineralized tissues even after diagenesis has occurred

bone preservation in hayonim cave israel a macroscopic and mineralogical study abstract understanding the cause of patchy bone distributions in archaeological sites requires that one distinguish bone decomposition in place from empty areas where bones were never present marked horizontal variations in bone abundance are found in the thick mousterian layer e of hayonim cave a large paleolithic site in northern israel infra red analyses of minerals in the sediments identify zones of advanced diagenesis and decomposition alongside zones whose chemistry clearly favoured the preservation of bones and wood ash these differences adhere closely to the distribution of recognizable bones in the deposits indicating that spatial variation in bone abundance is essentially a product of differential preservation conditions however the few bones present in the bone poor units are in surprisingly good condition the higher degree of abrasion damage and more random orientations of these bones indicate that small amounts of recent material were introduced into older layers by small burrowing animals and perhaps localized trampling the ratio of post mousterian to mousterian artifacts in layer e and the numeric contrasts in bone abundance among stratigraphic units indicate that time averaging from mechanical intrusion was quantitatively unimportant 2 5 throughout this 2 4 m thick layer our findings support karkanas et al 2000 suggestion that bone and ash mineral diagenesis in caves follow step wise rather than gradual transformations in geological time good preservation environments can be distinguished from poorer ones on the basis of mineral assemblages in sediments and deposits that once contained bone and wood ash can be identified long after the visible traces of these materials have disappeared

biofilm microfacies in phosphoritic units of the neoproterozoic halkal shale bhima basin south india abstract the phosphatic bands of the halkal shale of the neoproterozoic bhima basin record an anoxic paleoenvironment where only a few episodic depositional events introduced oxygen in thin sections five distinct microfacies caused by biofilms colonizing the ancient sea floor can be distinguished the microfacies document that low sedimentation rate allowed growth of biomass rich laminae sets whereas episodic influx of sand led to stacks of organic laminae alternating with fine sandy interlayers such depositional events may have also caused local rupture of biofilms and the release of small biofilm roll ups and clasts the ancient biofilms led to precipitation of phosphorous and iron rich minerals and likely contributed to phosphorite formation in modern equivalent environments sea floor colonizing biofilms include a high abundance of sulfide oxidizing and sulphate reducing bacteria

patterns of diagenesis in bone i the effects of site environments abstract we have measured a suite of diagenetic parameters for several populations of archaeological bones buried in a number of northwest european sites since the last ice age these are the structural damage due to microbes changes in bone micro and macro porosity protein content a measure of the crystallinity of hydroxyapatite as reflected in the phosphate infra red spectrum peak splitting and a measure of the carbonate content as given by the ratio of carbonate to phosphate infra red absorption peaks the results provide a database that clearly characterises the patterns which are often site dependent of diagenetic change in buried bone our main conclusions are that individual site hydrology appears to have a strong influence on the outcome of bone preservation and that porosity is the most effective single diagenetic parameter which both determines and reflects the preservation of bone in the burial environment

intra skeletal variability in trace elemental content of precolumbian chupicuaro human bones the record of post mortem alteration and a tool for palaeodietary reconstruction this study applies an intra skeletal sampling strategy to examine post mortem alteration of archaeological human bone from west mexico and to reconstruct ancient diet human bone from the chupicuaro culture mexico preclassic period constitutes an ideal material with which to examine subsistence strategies because the specific hydrothermal environment in which the population lived would have provided certain food components hydrothermal waters and carbonates with distinct signature in ca mg f li sr mn v and u values four to ten samples were taken from the long bones of six skeletons bone trace element content ca p f mn mg na li v zn rb sr ba y la ce nd th u and bone alteration parameters crystallinity organic matter and secondary calcite content were analysed at the intra skeletal level stable isotopic signatures bone d13c and d18ocarbonate and histological analyses were also performed on a single bone from each individual results indicate that all of the skeletons were affected by post mortem mineralogical structural and geochemical transformations biological bone d13c values seem preserved for most of the individuals but an increase in crystallinity accompanies depletion in bone d18o values the combination of bone alteration parameters with bone elemental content shows that in this very specific context a widespread dissolution recrystallisation is unlikely of the hydrothermal tracers sr f and li were of particular interest because their retention in living tissues is related to the amount ingested the intra skeletal li content does not reveal any pattern but li depletion is not excluded in contrast sr and f show a progressive intra skeletal diagenetic enrichment likely due to gradual diffusioneadsorption processes the bones with the lowest concentrations in these elements are assumed to yield the best representative ante mortem values the signal extracted from each skeleton a very unusually high bone sr f and li content is interpreted as reflecting the consumption of the local hydrothermal products which are also enriched in these elements

stable isotopic and geochemical identification of groundwater evolution and recharge sources in the arid shule river basin of northwestern china stable isotopic dvsmow and 18ovsmow and geochemical signatures were employed to constrain the geochemical evolution and sources of groundwater recharge in the arid shule river basin northwestern china where extensive groundwater extraction occurs for agricultural and domestic supply springs in the mountain front of the qilian mountains the yumen tashi groundwater ytg and the guazhou groundwater gzg were ca hco3 ca mg hco3 so4 and na mg so4 cl type waters respectively total dissolved solids tds and major ion mg2 na ca2 k so42 cl and no3 concentrations of groundwater gradually increase from the mountain front to the lower reaches of the guazhou basin geochemical evolution in groundwater was possibly due to a combination of mineral dissolution mixing processes and evapotranspiration along groundwater flow paths the isotopic and geochemical variations in melt water springs river water ytg and gzg together with the end member mixing analysis emma indicate that the springs in the mountain front mainly originate from precipitation the infiltration of melt water and river in the upper reaches the lateral groundwater from the mountain front and river water in the middle reaches are probably effective recharge sources for the ytg while contribution of precipitation to ytg is extremely limited the gzg is mainly recharged by lateral groundwater flow from the yumen tashi basin and irrigation return flow the general characteristics of groundwater in the shule river basin have been initially identified and the results should facilitate integrated management of groundwater and surface water resources in the study area copyright 2015 john wiley sons ltd

burning and boiling of modern deer bone effects on crystallinity and oxygen isotope composition of bioapatite phosphate abstract the extent of preservation of stable isotope compositions in biomaterials exposed to burial and weathering continues to be a topic of some debate changes in the isotopic composition of archaeological bones and teeth during recrystallization are often suspected but difficult to prove here we examined the effects of heating burning boiling on the isotopic composition of phosphate oxygen 18 o p in bone bioapatite from two modern white tailed deer odocoileus virginianus our experiments simulated cooking and refuse disposal practices which have affected many archaeological samples original values for 18 o p were preserved at 18 o p above 300 c original values for 18 o p were preserved only at ftir ci 2 5 2 7 xrd ci values were not sensitive to changes in 18 o p below 625 c

diagenetic changes on bone histology of quaternary mammals from a tropical cave deposit in southeastern brazil abstract karst caves are suitable environments for the accumulation and preservation of fossils cave deposits are often complex and the environmental conditions within cave sites result from intricate interactions between various biological physical and chemical factors however it is not fully understood how the complexity of the environmental conditions of caves influences bone diagenesis the study of the initial stages of bone diagenesis depends to a large extent on understanding the changes in the bone histology to contribute to this issue we examine a set of postmortem changes affecting the bone histology of quaternary mammals that accumulated naturally in locus 2 a pitfall site in cuvieri cave located in the tropical region of brazil our analyses show that bones deposited in caves may be subject to a peculiar set of environmental conditions that in tropical regions may prevent the preservation of bone histological structure the effect of diagenetic processes on the bones differs depending on the taphonomic stage of the bone and the diagenetic alterations appear to have influenced each other the deposition of bioclasts following the entrapment of individuals in locus 2 favours the proliferation of bacteria on bones and appears to be important in directing the diagenetic alteration the hydrological regime of the cave that is recharge with potential phases of higher humidity also is important in directing the diagenetic alteration and further decreased the preservation potential of the bone microstructure the formation of macroscopic and microscopic cracks related to bone weathering in caves shows that the taphonomic processes peculiar to these environments are poorly understood highlighting the need for more research to be conducted on cave taphonomy

diagenesis of bones from eland s bay cave abstract archaeological bone specimens have been shown in a number of studies to have increased mineral crystallinity when measured both by xrd and ir spectrometry in this study we investigated the relative dating potential of ir crystallinity measurements based on the splitting factor or sf on a sample of 54 specimens from the holocene sequence at eland s bay cave south africa in addition to sf c and n measurements were obtained using a carlo erba elemental analyser results of the study indicate that i a reasonably good correlation between sf and time exists in bones under 20 000 years bp but that the increase in sf levels off after this period and ii correlations between diagenetic indicators such as sf c and n are better than those between any indicator and time an excellent correlation r2 0 81 was obtained between sf residing in the inorganic phase and n residing in the organic phase suggesting that diagenesis of the two phases of bone are linked implications of the data for monitoring stratigraphic anomalies at archaeological sites are discussed

investigation of leakage at ataturk dam and hydroelectric power plant by means of hydrometric measurements abstract ataturk dam with its 84 5 million m 3 fill volume and 169 m height above the foundation is one of the largest dams in the world its 1 2 million m 2 grout curtain surface area is the largest constructed in the world to date the bozova fault crosses the dam axis in the left bank and extends towards the downstream valley the grout curtain constructed in karstic limestone is 180 m deep in the thalweg and partially extends to 250 300 m depths in some local zones on both the right and left sides of the valley in this study we have investigated leakage at the ataturk dam and hydroelectric power plant by means of hydrometric measurements the hanging grout curtain indicates that leakage at ataturk dam is of vital importance in defining the longevity of the dam hydrometric measurements including discharge temperature and electrical conductivity of springs and leakages were carried out for 9 years periodically in addition to monitoring performed before during and after construction the leakage increased as the reservoir water level rose seasonally but it was also discovered that this regular increase was not observed in the last three measurements the decrease in leakage volume in the last three measurements proved the integrity of the grout curtain and the efficiency of the microsol grout works recent seepage levels are within design limits and therefore have no serious effect on the stability of the dam structures

why do crystallinity values fail to predict the extent of diagenetic alteration of bone mineral spectroscopic indicators of bone crystallinity such as the infrared splitting factor irsf are commonly used to determine the general state of preservation of ancient bone in principle such indices might be expected to act as a proxy for alteration of bone mineral and thus could be used to screen bones or portions of bones for likely preservation of in vivo biogenic trace element and stable isotope signals we tested the relationship between irsf and bone mineral composition in two suites of well characterised recent and pleistocene bones initially crystallinity change and trace element uptake are correlated apparently both controlled by decomposition of the organic phase and exposure of bone crystal surfaces this relationship breaks down in older bones where authigenic phosphate growth and mineral pore water interactions are no longer rate limited by the breakdown of collagen and exposure of crystal surfaces in these conditions the extent of chemical alteration of bone will be controlled by site specific conditions and thus while ftir spectra of bone provide a broad indication of organic content and apatite recrystallisation they are not reliable proxies for the degree of diagenetic alteration in terms of biogenic geochemical signals

a review of apatites iron and manganese minerals and their roles as indicators of biological activity in black shales abstract biological contribution to the formation of minerals has become more than a descriptive area in geological thought and research mechanisms of specific mineral accumulation and deposition in oceancs lakes and even desert environment are studied using interdisciplinary approaches and applied in the interpretation of earth processes phosphorus iron and manganese are and probably were essential elements in life forms the common minerals of these elements apatite and magnetite for example can be found in a variety of sedimentary environments both ancient and modern where they could be useful indicator minerals to interpret geologic environments the crystal morphological structural and chemical including isotopic attributes of these usually fine grained minerals can be compared with bulk chemical and stratigraphic information to augment our understanding of the mechanisms of formation and diagenesis in sediments such as black shales

suspected microbial mat related crack like sedimentary structures in the palaeoproterozoic magaliesberg formation sandstones south africa abstract the occurrence of patchy preservation of ripples and of palimpsest ripples on many sandstone bed surfaces of the c 2 1 ga magaliesberg formation pretoria group transvaal supergroup south africa suggests that microbial mats grew within the upper parts of sandy deposits of the braid deltaic tidally controlled epeiric marine coastline palaeoenvironment inferred for this stratigraphic unit recently limited occurrences of petee ridges cracked sand layers elephant skin textures wrinkle structures and manchuriophycus like cracks have been found substantiating the envisaged role for microbial mats binding sandy sediment and providing cohesion during active sedimentation by fluvial and tidal processes ripple marks associated with most of these biogenic sedimentary structures enable evaluation of genetic processes for the ripples currents waves wind as well as estimation of wave heights and water depths cf tanner w f 1967 ripple mark indices and their uses sedimentology 9 89 104 tanner w f 1971 numerical estimates of ancient waves water depths and fetch sedimentology 16 71 88 the petee ridges are interpreted as reflecting spring low tidal desiccation which cracked the mats followed by disruption of sand beneath the mat due to loading from incoming tides or subsequent deposits slightly sinuous sand cracks on ripple crests are related to a similar combination of low tidal desiccation and formation of wind ripples with subsequent high tides providing the deeper water conditions and larger wave heights calculated from the tanner w f 1971 numerical estimates of ancient waves water depths and fetch sedimentology 16 71 88 formula synaeresis cracking is inferred for both elephant skin cracks and manchuriophycus structures these inferred suspect microbial sedimentary structures when studied in relation to data derived from associated ripples thus enable better estimation of depositional conditions within the magaliesberg palaeoenvironment and indicate minimum epeiric tidal ranges of c 112 cm in general these structures are found associated with evidence for shallower water and higher energy conditions which probably protected the microbial mats from degradation by heterotrophic bacteria through fast burial a possible association of such mat related structures with epeiric marine or passive margin coastline conditions may be pertinent for much of the precambrian clastic record

anomalous iron distribution in shales as a manifestation of non clastic iron supply to sedimentary basins relevance for pyritic shales base metal mineralization and oolitic ironstone deposits in previous investigations nearshore pyritic shale horizons in the mid proterozoic newland formation were interpreted to be due to non clastic colloidal iron supply by streams new data on the chemical composition of shales in the newland formation support this interpretation in these shales fe and al show a positively correlated trend that intercepts the fe axis above the origin these relationships suggest control of fe by clays via iron oxide coatings on clay minerals and the presence of an additional non clastic iron component shales from stratigraphic intervals during which pyritic shale horizons were deposited plot above the fe al trend typical for the remainder of the newland formation

geostatistical and geochemical analysis of surface water leakage into groundwater on a regional scale a case study in the liulin karst system northwestern china abstract the liulin karst system is typical of hydrogeological systems in northern china with a group of springs as the dominant way of regional groundwater discharge surface water leakage into groundwater has been observed in six sections of the rivers in the study area to extract hydrogeological information from hydrochemical data 29 water samples were collected from the system on a trilinear diagram most of the groundwater samples are clustered around the surface waters indicating the effect of leakage on their chemistry r mode factor analysis was made on seven variables na ca mg so 4 cl hco 3 and no 3 of the samples and three principal factors were obtained the f 1 factor is composed of ca mg and so 4 the f 2 of hco 3 and no 3 and the f 3 of na and cl these factors are then used as regionalized variables in ordinary kriging for unbiased estimates of the spatial variations of their scores considering regional hydrogeological conditions the hydrogeological implications of the spatial distribution of the factor scores as related to the effects of the surface leakage are discussed to evaluate the geochemical processes the geochemical modeling code netpath was employed the modeling results show that mixing commonly occurs in the system and dolomite dissolution is more important than calcite dissolution dedolomitization calcite precipitation and dolomite dissolution driven by anhydrite dissolution is locally important in the western flank of the system where the surface water leakage has the least effect

mineralogical changes in fossil bone from cueva del angel spain archaeological implications and occurrence of whitlockite the mineralogical changes undergone by fossil bones found in cueva del angel lucena cordoba were investigated in order to establish a first approximation to the site formation processes that occurred in the cave for this purpose 18 samples of fossil bones collected from the stratigraphic profile named j k the most complete of those studied on the site up to the present were analysed the results are interpreted as evidence of thermal events due to anthropic action on the basis of changes in colouration of the fossil bones increased crystallinity of phosphatic phases and occurrence of rare authigenic phosphates whitlockite diagenetic processes including phosphate authigenesis and presence of secondary precipitations of calcite and manganese oxides has been also observed the analytical evidences further indicate that temperatures of about 650 700 c were reached in stratigraphic units i and ii while less elevated temperatures were reached in stratigraphic unit iii

sulfur isotope constraints on the conditions of pyrite formation in the paleoproterozoic urquhart shale formation and george fisher zn pb ag deposit northern australia

trace element geochemistry and sedimentary provinces a study from the tasman geosyncline australia abstract the abundances of la th u and hf have been determined in flysch sequences of the tasman geosyncline australia the arc derived graywackes differ from those of rifted continental margins and marginal basins in containing low abundances of la th u and hf la 9 2 1 7 ppm th 1 4 0 6 ppm u 0 52 0 2 ppm hf 2 1 0 6 ppm reflecting similar low abundances in the andesitic source rocks graywackes of rifted continental margins and marginal basins in contrast are mature and characterised by high abundances of la th u and hf la 39 9 9 ppm th 16 0 6 ppm u 3 40 0 5 ppm hf 7 9 ppm mirroring increased abundances in the granitic and sedimentary source rocks sedimentary rocks deposited in inter arc basins show wide dispersion but have characteristics intermediate between these two types the th u ratio for magmatic arc sediments is 2 7 for most other sedimentary rocks it remains uniform at 4 5 0 3 for sediments having andesitic and dacitic rocks as provenance the la th ratios are 6 7 and 4 5 respectively this ratio remains constant at 2 6 for most quartzose sedimentary rocks

an x ray diffraction xrd and x ray fluorescence xrf investigation in human and animal fossil bones from holocene to middle triassic we examined by rietveld refinement of x ray diffraction patterns a series of 61 human and animal fossil bones in an age range from present time to middle triassic around 245 ma this approach supplemented by elemental analysis according to x ray fluorescence has permitted to obtain a quantitative evaluation of the mineralogical phases in the specimens thus allowing to reconstruct the mineralization process involved concerning the apatite phase after adopting a monoclinic geometry for the unit cell the method permits to determine with fair degree of precision the unit cell volume which is found to decrease in relatively short geological times as a function of the fluorine substitution process for the hydroxyl group oh after excluding the role of a high temperature fire treatment to the bones it is found that a certain linear correlation may exist over the geological time scale involved between the age of the specimen and the average crystallite size this observation permits to use the xrd pattern as an evaluation of the age of the fossil although the stratigraphic observations where available remain as the main reliable source for dating such biomaterials the uncertainty related to this age estimation may be hardly better than 15 20 in absolute because of various assumptions involved in the xrd methodology used and in the variability of the burial environment that may be subjected to discontinuous changes over the very long time of deposition

hydrochemical characteristics of aquifers near sutherland in the western karoo south africa the western karoo depends entirely on groundwater for domestic and agricultural use an understanding of the chemical evolution of the groundwater provides insight into the interaction of water with the environment and contributes to better resource management descriptive statistics correlation matrices and factor analysis together with stable isotope data were used to gain an understanding of the hydrochemical processes of the groundwaters in the fractured rocks around sutherland in the western karoo the main processes influencing the groundwater chemistry are salinisation mineral precipitation and dissolution cation exchange and human activity the stable isotope data indicate that the infiltration of evaporated water is partly responsible for the occurrence of saline subsurface waters the ionic oxygen and hydrogen stable isotope composition of the groundwaters suggests that the effects of localised topography are one of the overriding factors controlling the groundwater chemistry in higher lying areas ca hco3 2 type waters are prevalent while in topographical flat areas nacl type waters dominate in areas where water collects close to or at the surface saline soils are formed from these areas salts are leached to the subsurface during significant recharge periods these findings are important in that they contribute to the identification of suitable locations for developing groundwater resources that could yield a relatively better quality water q 2001 elsevier science b v all rights reserved

microbial signatures in peritidal siliciclastic sediments a catalogue a catalogue of microbial structural signatures is presented based upon the coupling of fundamental biogeochemical microbial processes and local morphogenetic determinants it summarizes a collection of sedimentary structures obtained from two modern siliciclastic peritidal environments in different climatic zones temperate humid mellum island southern north sea subtropical arid coast of southern tunisia textural geometries reveal a high structural diversity but their determinants are primarily based upon six major parameters 1 intrinsic biofactors structural diversification of sedimentary microbial films and mats inherent in the organisms i e their construction morphology growth taxis and behaviour and local abundance of specific morphotypes most prominent are the ensheathed filamentous cyanobacteria microcoleus chthonoplastes and lyngbya aestuarii and the sheathless filamentous cyanobacterium oscillatoria limosa 2 biological response to physical disturbances sediment supply erosion and fracturing of surface layers resulting from desiccation cause growth responses of biofilms and microbial mats 3 trapping binding effects physicobiological processes give rise to grain orientations and wavy to lenticular lamina lamina specific grain arrangements and sucrose calcium carbonate accumulations 4 secondary physical deformation of biogenic build ups mechanical stresses acting upon sediments overgrown and biostabilized by biofilms and mats produce erosional and overthrust structures 5 post burial processes textural fabrics that evolve from mechanical effects of gas formation from decaying mats and features related to the formation of authigenic minerals calcium carbonates calcium sulphates pyrite 6 bioturbation and grazing post depositional structures such as skolithos type dwellings traces of burrowing insects gastropod grazing traces and faecal pellets in synopsis the catalogue firstly comprises a sound set of ubiquitous signatures this uniformity in architectural characteristics is attributed to the presence and local dominance of certain microbes throughout the different settings the catalogue secondly documents signatures that are extremely sensitive to tidal position hydrodynamic regime and overall climatic conditions these kinds of signature indicate narrow facies zones which often coincide with the activity or dominance zones of certain organisms an overview of structures of microbial origin from the fossil record underlines the potential of many of the signatures included in this catalogue to become fossilized and provide strong indicators of former siliciclastic tidal settings

stratigraphic control of rare earth pattern types in mid proterozoic sediments of the belt supergroup montana u s a implications for basin analysis abstract within sediments of the helena embayment an eastern extension of the mid proterozoic belt basin montana u s a three different types of ree patterns were identified the lower part of the investigated sequence chamberlain shale and lower newland formation is a uniform shale interval which accumulated during a period of tectonic quiescence the ree patterns of these shales normalized to nasc are either flat or lree enriched lacking eu deficiencies the superjacent unit newland transition zone contains variable amounts of feldspathic sandstone it indicates rejuvenation of the hinterland and regression the uppermost unit upper newland formation consists of alternating packages of carbonates and shales ree patterns in shales of the newland transition zone and upper newland formation have negative eu anomalies this drastic change of ree patterns was observed in all stratigraphic sections the source rocks of the beltian sequence were probably dominated by granitoid gneisses and migmatites and rocks of this composition show negative eu anomalies against nasc in many other places the observed negative eu anomalies in the shales were probably inherited from the source rocks however the patterns of the chamberlain shale and the lower newland formation are not as easy to explain because the source rocks seem not to have changed during deposition of the beltian sequence perhaps more intense chemical weathering during chamberlain shale lower newland time obscured the negative eu anomalies in the residual clays adsorption of lree s on clays during transport may have caused the lree enriched patterns a change in tectonic regime and weathering intensity coincides with the stratigraphic distribution of the different ree pattern types thus stratigraphically controlled ree pattern distribution in a sedimentary basin may help to establish quasi time lines and may allow monitoring of tectonic pulses and of weathering conditions in the hinterland

genesis of the lower triassic bonebeds from gogolin s poland the impact of microbial mats on trapping of vertebrate remains abstract three bone bearing horizons consisting of seven bone bearing beds with fish and reptile remains were recently discovered in the uppermost rot buntsandstein lower triassic peritidal and shallow marine carbonates in the vicinity of gogolin s poland the aim of this study is to recognize the genesis and depositional environments of the bonebeds detailed fieldwork microfacies analysis and sem eds analysis reveal that the vertebrate remains occur to a great extent alongside evidence for former microbial activity the reptile remains represent at least dactylosaurus and nothosaurus sauropterygia genera while the fish remains belong to the chondrichthyes and actinopterygii the vertebrate remains were deposited in a transitional zone between the costal sabkha and the epicontinental sea the first bone bearing horizon originated in the most landward setting in the uppermost intertidal zone likely at the margins of a pond or coastal lagoon the second bone bearing horizon was formed in the upper intertidal zone the vertebrate remains of the third bone bearing horizon were accumulated in two different settings in the lower intertidal zone in a small palaeopond and in the subtidal zone in a protected back shoal lagoon three bone accumulations occur within planar stromatolites while the other bone bearing beds reveal more indirect evidence for former microbial activity in our opinion the presence of the sticky microbial mats in the intertidal settings was the crucial factor that allowed the establishment of and controlled these accumulations of vertebrate remains the soft gluey substrates trapped vertebrate remains that were transported across them once trapped the vertebrate bioclasts were efficiently immobilized and thus protected against damage due to sedimentological agents the lack of any orderly arrangement of the vertebrate bioclasts suggests that they may have been delivered to the individual mat surfaces by diverse media from various directions and also at different times

retention of hunter gatherer economies among maritime foragers from caleta vitor northern chile during the late holocene evidence from stable carbon and nitrogen isotopic analysis of skeletal remains abstract on the basis of stable carbon and nitrogen isotope analysis of human remains this paper provides evidence for the retention of hunter gatherer economies among coastal inhabitants in northern chile during the late holocene at the same time that inland populations were adopting agricultural economies coastal diets from the caleta vitor region of the atacama desert were dominated by marine based foods predominantly from upper trophic levels the focus on reliable marine food resources is interpreted as a risk minimisation strategy in this marginal arid environment although these coastal hunter gatherers adopted other goods and traditions from agricultural populations their participation in this larger interregional exchange network did not affect their basic subsistence economies associated new radiocarbon dates from the site are also discussed skeletal remains and artefacts associated with the caleta vitor shell middens generally originate from sites with dates ranging from c 9000 476 bp however the human remains that are the subject of this research cover the time period c 4000 476 bp

diagenetic evolution and experimental heating of bone phosphate abstract fresh bone samples have been experimentally heated with monitoring of the evolution of several parameters the comparison of these results with a large suite of measurements performed on archaeological and fossil bones gave valuable clues about some possible mechanisms of the diagenetic evolution of bone crystallinity the main conclusions of this comparison are that 1 bone organic matter protects the mineral phase and thus needs to be significantly altered before crystallographic changes occur and 2 loss of structural carbonate may be a key factor in the increase of bone crystallinity the crystallinity of carbonate hydroxylapatite seems to monitor the degree to diagenetic evolution and thus may be used to detect diagenetic alteration of biogenic paleoenvironmental signals in archaeological and fossil bones independently of their age

a sulfur isotope study of pyrite genesis the mid proterozoic newland formation belt supergroup montana abstract different generations of sedimentary pyrite from the mid proterozoic newland formation usa have been analysed for their sulfur isotopic compositions the results indicate bacterial sulfate reduction as the pyrite forming process the 34 s values for early diagenetic pyrite around 14 are in contrast to dominantly more positive values for many other middle proterozoic units a progressive reduction of sulfate availability during diagenesis can be recognized by an increase in 34 s content rayleigh distillation as well as through detailed petrographic observations contemporaneous seawater had a sulfur isotopic ratio between 14 and 18 as measured from sedimentary barite within the unit