an energy dispersive miniprobe multielement analyzer emma for direct analysis of trace elements and chemical age dating of single mineral grains abstract an energy dispersive miniprobe multielement analyzer emma was designed and constructed for the analysis of trace elements as cr cu fe ga ge hf mn ni pb rb se sr th y u zn in small individual mineral grains such as apatite garnet monazite sphene zircon and other accessory minerals the instrument is sensitive ppm for most elements rapid 3 6 min per analysis non destructive and essentially no sample preparation is required with respect to single zircon grains as small as 50 m with mass as low as a few g for example the detection limits for u th and pb are on the order of 10 ppm 5 10 times better than the electron microprobe here the emma is used to illustrate the variation in hf and y concentrations in single zircon grains from pegmatites granites basalts carbonatites and kimberlites also the instrument is used for chemical age dating u th total pb of 1 single zircon grains from the berdyshevsky intrusive complex ukraine and 2 single monazite grains from a small placer deposit within the transition zone between the saxothuringikum and moldanubikum bavaria germany the average age of the single zircon grains from berdyshevsky granite determined using emma 2 19 0 17 ga 1 is consistent with the u pb zircon intrusion age of this complex 2 14 0 07 ga and monazite data ranging from 1 95 to 2 48 ga with respect to the pegmatite from this complex the average age of 1 93 0 09 ga found with emma is geologically consistent with zircon and monazite ages ranging from 1 90 to 2 29 ga regarding the monazite grains from the placer the age dates obtained using emma 328 28 ma are comparable to the isotopic ages conventional u pb and pb pb step leaching which yielded ages of 312 3 and 324 12 ma respectively

sand ramps in the golden gate highlands national park south africa evidence of periglacial aeolian activity during the last glacial abstract sand ramps have been identified in a side valley on the southern side of the little caledon river in the golden gate highlands national park free state south africa the site lies in the foothills of the northern drakensberg maluti mountains and this study aims to explore the potential of such deposits to add to the sparse palaeoenvironmental record of the region up to 11 m of aeolian sand banked against north facing slopes is exposed by fluvial incision through the deposits revealing interbedded fluvial lenses and palaeosols the region is currently devoid of significant aeolian sediment transport or deposition and supports well developed grassland vegetation these deposits testify to former conditions different from those of today which would have been characterised by depleted vegetation and a different wind and or climatic regime biogenic proxies are absent from the deposits but optically stimulated luminescence osl dating of the sediments reveals that they accumulated at intervals throughout much of the last glacial event from around 45 to 16 ka these dates are consistent with those of vegetation changes from palaeoecological sites elsewhere in the region and also with dated evidence for niche glaciation further south in the high drakensberg evidence from this study supports significant landscape changes in the drakensberg during the last glacial with the foothills in the region of golden gate highlands national park subject to aeolian processes under a periglacial environment

phytoliths indicators of grassland dynamics during the late holocene in intertropical africa abstract the reconstruction of african tropical grassland history during the late holocene can be carried out using phytolith analysis fossil phytolith assemblages from lake guiers in the sahelian region of senegal and from lake sinnda in the guineo congolian region of congo were investigated the results are interpreted on the basis of modern phytolith assemblages from the same regions and compared to pollen data previously obtained tall or short grass associations are discriminated by their phytolith index iph saddle cross dumbel saddle while the density of shrubs and trees is indicated by relative proportions of the dicotyledon phytoliths the phytolith data emphasize that in the guineo congolian region around lake sinnda the driest phase of the late holocene occurred between 4000 and 1200 yr b p commencing with the opening of the dense forest and its replacement by a short grass savanna from ca 1000 yr b p wetter climatic conditions developed as represented by the setting up of a tall grass savanna woodland the modern shrub and tall grass savanna was developed ca 700 yr b p in the sahelian region around lake guiers the driest phase occurred after about 2000 yr b p and has not been followed by moister conditions a tall grass savanna woodland was gradually replaced by a shrub and short grass savanna which still occurs a short period of development of swampy vegetation which can be related to a lake level change interrupted the semi arid adaptation of the vegetation between about 2000 yr b p and the present

palaeoecological implications of the lower pleistocene phytolith record from the dmanisi site georgia archaeological investigations of the lower pleistocene deposits at dmanisi lesser caucasus georgia have yielded an assemblage of hominin and faunal remains within a well dated context although abundant vertebrate fossils have been recovered paleobotanical studies have been limited to address this phytolith analysis has been conducted on two sections in order to reconstruct the distribution and evolution of vegetation throughout the entire sedimentary sequence large concentrations of phytoliths were recovered and analysed permitting the reconstruction of climatic indices the environmental data obtained from these phytolith assemblages are consistent with other palaeoecological data i e geological faunal and other archaeobotanical records when considered together they indicate an environment in which grasses were well represented in addition the climatically important water stress indices derived from dmanisi s phytolith assemblages suggest a period of increased aridity in the middle part of the stratigraphic sequence which is contemporaneous with human occupations of the site

the occurrence and significance of biogenic opal in the regolith abstract biogenic opal produced by vascular plants diatoms and siliceous sponges have been found in soils and terrestrial sediments of all continents except antarctica since the middle of the 19th century the opal particles range in size from fine silt to fine sand almost all soils contain detectable opal up to levels of 2 3 and a significant number contain values in excess of 5 even higher values have been found from soils and sediments of all continents in a wide range of soil types the most important factor is poor soil drainage and seasonal to permanent water logging this encourages the proliferation of silica producing organisms such conditions have been found in the soils and aquatic sediments of the monsoonal tropics tropical rain forests temperate forests tropical savanna tropical islands semi arid grasslands and savanna and temperate woodland and grassland the presence of a volcanic substrate also appears favourable in some cases but is not necessary biogenic opal preferentially collects in the a horizon of soils and to a lesser extent in the b horizon this preferential distribution facilitates identification of palaeosols in stacked soil sequences biogenic opal is also a component of windblown dust even in arid environments biogenic opal is significant to regolith processes in a number of ways firstly as in the case in marine environments it is likely to be important in silica cycling and storage because of its greater lability compared to quartz secondly dissolution and reprecipitation of opal a as opal ct or micro quartz may play a role in cementation and silicification of regolith to form silica hardpans and silcrete thirdly the organisms that form biogenic opal can have considerable palaeoenvironmental significance and be valuable in reconstructing regolith evolution finally some forms of biogenic silica in particular sponge spicules can present a health hazard their high abundance in some soils and sediments needs to be considered when assessing the health implications of airborne dust

prospection of two circular bronze age ditches with multi receiver electrical conductivity sensors north belgium two types of electrical conductivity sensors were evaluated to prospect circular ditches surrounding former bronze age burial mounds complementing aerial photography the first sensor was based on the electrical resistivity er method while the second sensor was based on frequency domain electromagnetic induction fdem both sensors were designed with multiple receivers which measure several depth sensitivities simultaneously first the sensors were tested on an experimental site where a rectangular structure with limited dimensions was dug in a sandy soil the structure appeared as a higher conductivity anomaly in the low conductivity sand then both methods were applied on two bronze age sites with different soil properties which were discovered by aerial photography the first site in a sandy soil gave only very weak anomalies soil augering revealed that the ditch filling consisted of the same sandy material as the surrounding therefore this filling was not able to cause a high conductivity contrast due to its lower sensitivity to noise in the low conductive range the er sensor produced a more pronounced anomaly than the fdem sensor the second site was located on top of a ridge with a shallow substrate of tertiary coastal sediments the ditch was very clearly visible on the sensor maps as a conductive low at this location the soil augering revealed that the ditch was dug through an alternating clay sand layer and subsequently filled up with silty material from the topsoil overall the shallow receiver separation produced anomalies that were both stronger and that corresponded better to the geometry of the ditches the other receiver separations provided more information on the natural soil layering and in the case of the er array they could be used to obtain a cross section of the actual electrical conductivity with 2 d inversion modelling the results of this study proofed that conductivity sensors can detect bronze age ditches with varying contrast depending on the soil geomorphology moreover the sensor maps combined with soil observations by coring provided insight in the environmental conditions that influence the contrast of the anomalies seen on the aerial photographs and the sensor maps

opaline and al si phytoliths from a tropical mire system of west malaysia abundance habit elemental composition preservation and significance abundant and unique opaline and al si phytoliths and opaline bioliths have been discovered in holocene peat deposits of tropical tasek bera in peninsular malaysia these are secreted mainly by plants higher plants and algae and incorporated in the sediment cycle during the rapid biomass turnover many wetland plants have entire skeletons secreted the study shows that differing plant parts of same species as well as same parts of differing plant species incorporate different amounts of elements whilst deciduous trees of the swamp forest have phytoliths enriched in al most phytoliths of palms sedges and grasses of the littoral swamp are composed of opaline silica incorporation of al and many other elements into relatively stable phytoliths is the result of high evapotranspiration rate and ample plant available elements and can serve to detoxify the soil solution because of the abundance of such opaline and al si structures spongillid and algal remains in acid peat accumulating environments tropical peatlands represent repositories of si and al which together with variable amounts of other elements could provide the prime material for silicate neoformation during later diagenetic processes neoformation of minerals from bioliths would explain the scarcity of biogenic remains in carboniferous and tertiary coal deposits furthermore incorporation of major elements in phytoliths may limit the rate of leaching of these elements in an environment where biomass turnover is rapid thus reducing the loss of nutrients and other plant essential elements most nutrients of tropical peats are recycled by plants within the top 150 cm and an upward migration of plant essential elements such as mg ca or p but also of si and al occurs during peat accumulation such elemental cycling strongly influences the geochemical composition of the peats during mire evolution utilizing al for normalization of major and minor elements of tropical peats for paleoclimatic and paleodepositional analyses may thus result in incorrect interpretations

paleopedologic and geomorphic evidence for holocene climate variation shortgrass steppe colorado usa abstract radiocarbon dates of paleosols in northeastern colorado indicate distinct periods of stability and soil formation with intervening periods of instability resulting in soil truncation or burial a combination of pedologic and geomorphic indicators were used to resolve the duration of and prevailing climate during these periods five sites each having a paleosol were examined using both traditional soil analyses and grain size statistics the latter to decipher the mode of parent material deposition twenty local stream dune and bedrock deposits were analyzed using grain size statistics to establish benchmarks for comparison with soils field investigation supported by grain size frequency statistics indicate early holocene middle holocene and contemporary soils all formed in alluvium organic c and phytolith data suggest the early and middle holocene climatic conditions were more favorable for plant productivity than the present climate soil development in early and middle holocene paleosols suggests wetter soil moisture regimes than present low parent material carbonate contents suggest an eolian source for the carbonate in the bk and btk horizons the presence of paleosol btk horizons suggests a decrease in precipitation at the end of soil forming intervals followed by drought and subsequent soil burial

regional aeolian dynamics and sand mixing in the gran desierto evidence from landsat thematic mapper images spatial variations in sand composition were mapped on a regional scale in a terrestrial sand sea the gran desierto of sonora mexico mesoscale mapping on a satellite image base allowed quantitative interpretation of the dynamic development of sand sheets and dunes the results were used to interpret the quaternary geologic history of the tectonically active region at the mouth of the colorado river landsat thematic mapper multispectral images were used to predict the abundance of different mineralogies of sand grains in a mixed aeolian terrain a spectral mixing model separated the effects of vegetation and topographically induced shading and shadow from the effects produced by different mineral and rock types compositions determined remotely agreed well with samples from selected areas within the spectral limitations of the thematic mapper a simple discrimination capability for active versus inactive sand surfaces is demonstrated based upon differences in the percentage of low albedo accessory grains occurring on dormant aeolian surfaces a technique for discriminating between low albedo materials and macroscopic shade is implemented by combining thermal images with the results of the spectral mixing model the image analysis revealed important compositional variations over large areas that were not readily apparent in the field

small scale spatial resolution of the soil phytolith record in a rainforest and a dry forest in costa rica applications to the deep time fossil phytolith record abstract phytolith analysis a well established tool in archaeology and quaternary paleoecology has become a source of data for deep time paleoecological studies only in the last 15 years recent years have also witnessed the publication of numerous soil phytolith inventories from extant vegetation types representing modern analogues however this work suffers from several methodological shortcomings limiting inter study comparisons and the development of a single and repeatable protocol for soil sample collection in this paper we focus on two fundamental methodological questions that must be answered before modern analogue studies can be meaningfully applied to deep time paleoecology 1 do phytoliths from the lower portion of the a horizon more commonly preserved in paleosols reflect standing vegetation equally well as the upper a horizon which is more commonly used in modern analogue studies but often truncated by erosion in paleosols 2 does a point soil sample usually collected from paleosols capture standing vegetation as accurately as a composite soil sample commonly used in modern analogue studies which is made from subsamples taken from a small area to address these questions we collected soil from 10 10 m quadrats in a rainforest la selva and a dry forest palo verde in costa rica and compared phytolith assemblages from upper vs lower soil a horizons and composites vs single phytolith assemblages at both sites phytolith assemblages from the lower vs upper a horizon and from single vs composite samples provide similar vegetation structure signal despite some compositional differences these results suggest that the typical approach in deep time paleoecology of taking point samples from the lower a horizon of paleosols is likely justifiable at least for paleosols reflecting rainforest and dry forest soils we discuss possible mechanisms driving differences between sites and future approaches to further expand and test our results

studying urban stratigraphy dark earth and a microstratified sequence on the site of the court of hoogstraeten brussels belgium integrating archaeopedology and phytolith analysis abstract soil micromorphology has become an important tool in urban archaeology to investigate enigmatic dark humus rich apparently homogeneous units known as dark earth it has also proven to be of great value to study microstratified sequences such as floors allowing a finer grained picture phytolith studies have also shown to be of particular interest to investigate archaeological layers especially where other botanical remains are poorly preserved the integration of phytolith studies and micromorphology allows understanding of the distribution and orientation patterns of the phytoliths and their relation to other features fabrics contributing to a better understanding of taphonomical processes and the identification of different human activities the aim of the present article is to demonstrate the possibilities of such an integrated approach by the example of the site of the court of hoogstraeten situated near the top of a steep slope next to the palace of the dukes in the centre of brussels belgium the present article focuses on one complex sequence that includes two levels of dark earth and a microstratified sequence the integrated study demonstrates that the formation of the dark earth on the site of the court of hoogstraeten results from multiphased processes whereby various human actions interact with natural phenomena among the human activities pasturing crop growing manuring and composting have been identified the microstratified sequence has been identified as a potential floor layer as such this approach does not only allow understanding the site formation processes both from homogenised units like dark earth and microstratified ones but also identification of ancient activities that are rather difficult to interpret based on field data alone

environment and landscape management during the middle neolithic in southern france evidence for agro sylvo pastoral systems in the middle rhone valley abstract rescue excavations in the middle rhone valley have provided opportunities to develop innovative strategies for the study of palaeoenvironments these strategies involve sampling and analysis of botanical remains recovered not only from archaeological sites but also in off site pedosedimentary sequences thought to be poor in botanical remains thus these remains phytoliths pedo charcoal give access to unexplored depositional contexts such as alluvial plains moreover off site data are useful because they minimise the hazard of cultural bias e g selection of species during wood gathering comparison of data collected in the alluvial plain with data obtained via anthracological analyses of karstic caves and rock shelters in the hinterland suggests a complex agro sylvo pastoral management of the landscape during the middle neolithic we propose a pattern that supposes considerable specialization in use of plains vs slopes in the landscape and a strong and continuous human pressure on the vegetation and soils between 4500 and 3500 cal bc nevertheless these constraints are not sufficient to explain the persistence of such a system for more than a millennium favourable climatic conditions are thought to have been a determining factor in the persistence of an ecologically meta stable relationship between human societies and their natural environment

phytolith assemblages as indicators of coastal environmental changes and hurricane overwash deposition we demonstrate that phytolith assemblages are a useful proxy for reconstructing coastal environmental changes and for validating the overwash origin of sand layers in palaeotempestology studies phytolith analysis was conducted on 50 topsoil or surface sediment samples collected from a variety of coastal plant communities or depositional environments in the southeastern usa the data suggest that different coastal subenvironments can be distinguished by their modern phytolith assemblages for example coastal marsh samples contain a diverse phytolith assemblage dominated by smooth elongate and square morpho types and maritime forest samples are dominated by phytoliths from palms and broadleaf dicotyledonous plants remarkably the phytolith assemblages from sand dunes are characterized by high percentages of two horned tower flat tower spool horned tower and short saddle types phytolith analysis of three prehistoric sand layers in a sediment core from western lake northwestern florida shows that they contain a phytolith assemblage similar to those characteristic of sand dunes and interdune meadows these observations are confirmed by the results of principal components analysis and discriminant analysis on the modern and fossil phytolith data sets our study results support the interpretation that the sand layers in western lake were indeed formed by the erosion of sand dunes during overwash processes caused by landfalling catastrophic hurricanes

phytolith transport in soil a field study using fluorescent labelling abstract soil phytoliths have been widely applied to reconstruct vegetational history to date however the transport behaviour of phytoliths in soil is poorly understood causing uncertainties in the interpretation of phytolith data the present study was therefore designed 1 to determine transport rates of phytoliths in loamy and sandy soils under field conditions and 2 to elucidate the effect of phytolith size and shape on their transport behaviour in sandy and loamy soils for this purpose we adopted a fluorescent labelling technique from veterinary science the phytoliths were extracted from common reed phragmites australis labelled with the fluorescent dye fluorescein isothiocyanate and applied to a loamy sand soil haplic cambisol and a silty loam soil stagnic luvisol in southern germany one year after application the soils were sampled to analyse phytolith distribution with soil depth the weighted mean transport distance of phytoliths after one year was 3 99 1 21 cm for the cambisol and 3 86 0 56 cm for the luvisol phytolith size significantly affected transport behaviour indicating a preferential translocation of small sized phytoliths our study provides direct evidence for a significant downward mobility of phytoliths in sandy and loamy soils under natural conditions this should be taken into account when using phytoliths as palaeoenvironmental tracers quantifying phytoliths in soil with fluorescent labelling makes it possible to identify artificially applied phytoliths without using the conventional extraction method

reconstruction of the late pleistocene grassland of the columbia basin washington usa based on phytolith records in loess abstract silica phytoliths preserved in three loess sections in southeastern washington state revealed a 100 000 year history of the columbia basin grassland changes in the proportion of different morphotypes indicate large shifts in vegetation composition during the last 100 ka a low elevation section 677 m asl near the center of the basin provided a record of alternating xeric festuca poa and mesic festuca koeleria grassland the middle slope section 1095 m asl supported picea abies or pinus ponderosa forest or non analog parkland at different times some trees were present at or near the site even during the last glacial maximum the highest site 1220 m asl supported stipa festuca and poa dominated grassland with some artemisia shrub during most of the late pleistocene but supports a coniferous forest today variations in vegetation can be explained as a response to changes in large scale climatic controls grasslands and shrub steppe were apparently more widespread and forests more restricted than today during the marine isotope stages 2 and 4 probably as a result of cooler and drier conditions the three new records are well correlated with previously published paleo reconstructions based on phytolith cicada burrow and stable isotope data from a nearby kp 1 loess section carp lake pollen record and global ice volume variations

quantitative distribution of phytoliths as reliable diagnostical criteria of ancient arable lands abstract people ploughed the soils in the central part of russia for at least two thousand years based on historical documents and archaeological artifacts however we cannot find any traces of ancient arable land because after a 200 250 year uncultivated period all morphological and chemical properties have disappeared two soils near moscow russia were studied buried and modern the first soil was under an 800 year old burial mound and the second one was nearby it seemed that modern soil was also tilled in the past but nothing in morphology and chemical properties indicated that we used phytolith analysis to investigate if a typical arable distribution of phytoliths has been preserved in the soil after an 800 year uncultivated period the ancient plough layer has been completely transformed within the past 700 800 years its smooth lower boundary has totally disappeared and its chemical characteristics have changed including the reaction of soil solution organic matter distribution content and distribution of various forms of iron it is possible to distinguish some stable indicators of ploughing which have weakly changed even after a period of 700 800 years and allow us to interpret the ancient land use such indicators include the distribution of bulk phosphorus while the native soils show an accumulative trend with maximal concentration of total phosphorus within the sod horizon the arable soils are characterized by a uniform level of total phosphorus throughout the plough layer and in some cases also enrichment in this element along the former plough line lower boundary of plough horizon the other relatively stable indicator is the clay distribution pattern the eluvial illuvial distribution pattern is preserved in both buried and modern soils during the arable period of land use a special pattern of phytolith distribution was formed within the upper part of the soil with the maximum concentration of phytoliths along the plough line this pattern has been preserved for hundreds of years with only a slightly smoothened shape therefore the quantitative distribution of phytoliths within a soil profile is a stable indicator that can serve as a reliable diagnostic feature of ancient arable stages even when all other diagnostic indicators are absent the presence of phytoliths from cultivated cereal crops dendritic form within the upper layer is an additional confirmation of the former arable use of the soil

multidisciplinary approaches to the geoarchaeological evaluation of deeply stratified sedimentary sequences examples from pleistocene and holocene deposits in southern england united kingdom archaeological evaluation of deeply stratified sedimentary sequences from lowland river valleys can be problematic because of the often excessive depth of the deposits the associated high level of the water table and ground instability in such situations conventional archaeological survey techniques are inappropriate and alternative methodologies are required one suitable approach is to model subsurface stratigraphy in an attempt to determine potential locations for buried archaeology using an integrated borehole and geophysical program of ground investigation information of this type is often available in the form of geotechnical data that can be usefully augmented by geoarchaeological targeting of selected areas of the site for further information in this paper we show how such techniques can be used to model buried gravel surfaces peats within alluvial stacks and buried former clifflines in holocene and pleistocene sediments from southern england

40ar 39ar dating and phytolith analysis of the early pleistocene sequence of kvemo orozmani republic of georgia chronological and palaeoecological implications for the hominin site of dmanisi abstract the kvemo orozmani locality contains a 15 m thick early pleistocene fluvio lacustrine sequence bracketed by two lava flows located 13 km up the masavera river valley west from the dmanisi site kvemo orozmani is therefore of prime interest to improve the paleoecological framework as well as dating dmanisi 40 ar 39 ar ages obtained on the two lava flows indicate that kvemo orozmani sequence brackets the dmanisi sediments between 1 825 0 021 ma and 1 765 0 021 ma phytolith assemblages found at the bottom of the sequence indicate a warm and humid climate while the assemblages found at the top suggest dryer colder climatic conditions the shift in phytolith assemblages observed at kvemo orozmani is similar to the one already described in dmanisi and occurs near the end of the oluduvai subchron the new palaeoecological and chronological data confirm the hypothesis made in dmanisi about the palaeoenvironmental context during the hominin occupation that suggests a temperate climate becoming drier the age we obtained on the overlying lava flow establishes a minimum age for the climatic transition at both kvemo orozmani and the dmanisi site of 1 765 0 021 ma

dust production by abrasion of eolian basalt sands analogue for martian dust dust is nearly ubiquitous on mars covering much of the planet s surface having been redistributed by dust storms analysis of dust via landed instrumentation indicates a basaltic composition for its protolith the same is interpreted for the dark dune sands encountered at rover field sites in this paper we used samples of aeolian sands derived from basaltic volcanoes in an experiment to simulate dust production from basalt dune sands within an abrasion chamber in addition we used samples from gypsum dunes because gypsum is found within dune fields on the northern plains of mars the results expressed as weight of sample reduced to dust show a remarkably broad range over four orders of magnitude aeolian abrasion of basalt sands can produce similar amounts of dust as is the case for some desert sands on earth some plausible mars analogue materials can produce large amounts of dust suggesting that aeolian movement of basaltic sand and volcanic sediments on the surface of mars is a potential source of fine grained sediment or dust

calibrating grass phytolith assemblages in climatic terms application to late pleistocene assemblages from kansas and nebraska abstract the use of modern phytolith assemblages for the interpretation of fossil phytolith assemblages demonstrates the utility of phytolith analysis in reconstructing grassland vegetation and climate in the great plains of north america the modern data presented are the typical average assemblages for 34 modern localities taken throughout the great plains modern assemblage variability across the region is substantial this variability shows a coherent geographical pattern consistent with modern grassland composition these modern phytolith assemblages are calibrated in terms of modern climate data specifically july mean temperature seven fossil assemblages from three late pleistocene localities in the central great plains are presented two alternative phytolith temperature regression models are applied to these fossil assemblages to estimate paleo temperature resulting estimates are consistent with other efforts to calculate late pleistocene temperature departures in the region ca 8 0 to 7 0 c the fossil data also show rapid change in grassland composition and climate during the pleistocene holocene transition these results demonstrate how phytolith analysis can complement or substitute for pollen analysis in the great plains of north america

paleoenvironmental history of post toya ash tephric deposits and paleosols at iwate volcano japan using aeolian dust content and phytolith composition abstract physicochemical mineralogical and geochemical analyses of post toya ash 90 130 ka tephric and aeolian deposits at the foot of iwate volcano northeastern japan revealed the accumulation of deposits of long range aeolian dust transported from the asian continent and interstratified with the tephric deposits oxygen isotopic ratios of quartz in the 1 10 m fractions from two paleosols formed in the aeolian units shibutami cracked layers are 16 2 and 17 0 consistent with this fine grained quartz being of an aeolian origin the accumulation of asian aeolian dust onto tephric deposits in northeastern japan was dominant in the cold stages of the last glacial period 20 34 ka and 50 70 ka we determined the changes in vegetation and climate by using opal phytolith distribution in the tephra and aeolian deposits and associated paleosols similarly we interpreted the paleoenvironmental history of the tephric deposits by relating the vegetation history to the dust flux and fossil periglacial phenomena i e involution observed on tephra beds the paleoclimate sequence obtained coincides closely with the marine oxygen isotope curves indicating that opal phytolith analysis is useful in determining the interglacial glacial cycle recorded in aeolian and tephric deposits

soil phytoliths as indicators of initial human impact on san cristobal island galapagos abstract i analyzed phytoliths from soil profiles on san cristobal island in the galapagos islands to determine whether historical human impact and recent vegetation dynamics are visible in the phytolith record i extracted phytoliths from soil samples taken from four test pits located at the village an abandoned field a forest and an active agricultural field all located within the former el progreso plantation ad 1860 1920 changes in the ratio of tree to grass phytoliths with depth in all four samples suggest changes in vegetation composition from forest to open vegetation dominated by grasses which reflects the removal of forest with colonization and the first permanent human occupation of the archipelago in the middle 19th century this paper shows that the changes in vegetation brought about by colonization and land clearing for plantations are documented in the soil phytoliths record and suggests that phytoliths can be used as an indicator of past vegetation change in future work on the historical ecology of the galapagos archipelago

soil phytoliths from miombo woodlands in mozambique this paper describes topsoil phytolith assemblages from 25 loci underneath miombo woodlands on an eco transect intersecting the mozambican rift along a geographical altitudinal climatic and botanical gradient we provide the first comprehensive overview of the phytolith spectrum that defines northern mozambique s zambezian floristic zone our classifying criteria derive from comparison with previously described and quantified reference collections of trees and grasses growing in the study area we characterize the sedimentological and soil features of the matrices where phytoliths are found establishing correlation among geo edaphic variables and phytoliths descriptive statistics along with nonparametric and parametric statistical analyses evaluate phytolith grouping criteria variation robustness and membership from a taphonomic perspective we attest that topsoil phytolith assemblages are polygenic and do not represent an episodic snapshot of extant vegetation but a palimpsest from plants representing various disturbance episodes succession stages and ecological trends phytoliths retrieved from mozambican miombo soils do not seem to trace altitudinal temperature or precipitation gradients and no significant differences exist between highland and lowland phytolith assemblages this article provides a phytolith analog for woodland environments that can guide future paleoenvironmental research it also confirms that phytolith analysis is able to detect shifts in the woodland grassland interface

vegetational history of a site in the central amazon basin derived from phytolith and charcoal records from natural soils abstract analysis of phytoliths and macroscopic charcoal from natural soils near manaus brazil shows that the central amazonian terra firme forest has not been stable during the holocene phytolith taxonomic composition and radiocarbon ages indicate that a closed forest has continuously existed in the area since at least 4600 yr b p but that forest composition and species abundance changed significantly sometime during the holocene epoch there is no evidence that the vegetation experienced swidden cultivation the distribution and dates of the charcoal in the soils indicate that forest fires between 1795 and 550 yr b p burned an area of about 200 hectares vegetational changes and fires appear to be a result of climatic drying that may have affected large areas of the amazon basin over the past 5000 to 7000 years soil phytolith analysis is a promising tool for the study of environmental history in the humid tropics and may reduce the previous dependence on lake and swamp sediments at least for the holocene epoch

dark material in the polar layered deposits and dunes on mars viking infrared thermal mapping and bistatic radar data suggest that the bulk density of the north polar erg material is much lower than that of the average martian surface or of dark dunes at lower latitudes we have derived a thermal inertia of 245 280 j m 2 s 1 2 k 1 5 9 6 7 10 3 cal cm 2 s 1 2 k 1 for the proctor dune field and 25 150 j m 2 s 1 2 k 1 0 6 3 6 10 3 cal cm 2 s 1 2 k 1 for the north polar erg the uniqueness of the thermophysical properties of the north polar erg material may be due to a unique polar process that has created them the visible and near infrared spectral reflectance of the erg suggests that the dark material may be composed of basalt or ferrous clays these data are consistent with the dark material being composed of basaltic ash or filamentary sublimate residue fsr particles derived from erosion of the layered deposits dark dust may be preferentially concentrated at the surface of the layered deposits by the formation of fsr particles upon sublimation of water ice further weathering and erosion of these areas of exposed layered deposits may form the dark saltating material that is found in both polar regions dark fsr particles may saltate for great distances before eventually breaking down into dust grains re mixing with the global dust reservoir and being recycled into the polar layered deposits via atmospheric suspension

late holocene phytolith and carbon isotope record from a latosol at salitre south central brazil abstract the reliability of paleovegetation records inferred from soil phytolith assemblages and som soil organic matter carbon isotope analysis was examined in light of previous pollen and charcoal reconstructions the sampled latosol is located in south central brazil salitre at a boundary between forest and cerrado the derived mean age of phytoliths and som at each level is the result of a balance between continuous translocation and selective dissolution it increases with depth in a regular quantifiable fashion that allows paleoenvironmental interpretation phytoliths and som tracers first record a savanna phase associated with the last holocene long dry period occurring between ca 5500 and 4500 yr b p two periods of tree community development followed between ca 4000 and 3000 and after ca 970 yr b p leading to the present cerrado forest association the dry spell interrupted this trend about 970 60 yr b p the second development of woody elements was contemporaneous with an increase in anthropogenic fires therefore climate was more important than fires and human activities in constraining the growth of vegetation during the last nine centuries at salitre more generally despite pedogenic processes soil phytoliths and 13c values of the som may be accurate tracers of vegetation changes

phytoliths as paleoenvironmental indicators west side middle awash valley ethiopia phytolith assemblage analysis offers the potential to refine our knowledge of paleoecosystems where grasses and sedges predominate in this work holocene and pleistocene sediments from an arid tropical region in ethiopia have been analyzed for their phytolith content presented as detailed counts and diagrams according to the twiss classification the aim is to test the usefulness of phytolith assemblages to indicate paleoenvironments at middle awash where fossil pollen grains are poorly preserved in sediments that yielded abundant archaeological remains the vegetation in the middle awash subdesertic valley is currently a shrub steppe dominated by c4 grasses adapted to arid conditions with a narrow riparian forest limited to the awash river our results show that modern surface samples holocene and pleistocene sediments contain well preserved and different phytolith assemblages and therefore that no translocation processes from modern soil to geological strata seem to occur fossil records and modern assemblages are interpreted using phytolith ratios to estimate the density of the tree cover the aridity and the proportion of c3 versus c4 grasses as applied to phytolith assemblages from north america and west africa the phytolith assemblages from modern soil samples correctly reflect the proportion of trees and shrubs versus grasses different in the riparian vegetation and the shrub steppe modern phytolith assemblages appear to be a mixed signature of local and regional vegetation phytolith analysis of the holocene sample suggests a grassland where the grass community is constituted by the chloridoideae subfamily adapted to warm and dry conditions and where c3 pooideae cover the highlands phytolith analysis of the pleistocene sample evidences grassland formation with scattered woody elements where c4 panicoideae grasses adapted to warm and humid conditions dominate the grass cover however these conclusions need to be confirmed by more complete study on phytolith assemblages from modern vegetation from ethiopia

the role of phytolith formation and dissolution in controlling concentrations of silica in soil solutions and streams abstract by integrating the results of recent studies on the concentration and flux of si in european forest soils podzols and acid brown soils with published evidence on the amounts of si cycled through forest vegetation we conclude that phytoliths must be the principal immediate source and sink of silica in soil solution although mineral weathering is the ultimate source during the growing season forest vegetation takes up most of the si made available by weathering of soil minerals and by phytolith dissolution and converts it into phytoliths phytoliths will be the principal source of si leached from the soil during winter rains and spring snowmelt this work accounts for the plateau concentrations of si observed in laboratory equilibrations of bs horizon soils for the maximum si concentration reported for b horizons in the field for a deep sink for si in bs horizons and for the fact that the concentrations of si in soil drainage water and in streams all fall in or below the range expected for phytolith solubility concentrations of si in surface horizons can exceed these levels during droughts the common assumption that the concentration of si in soil solution is a result of a dynamic balance between si released by mineral weathering and that lost by leaching is untenable for bs horizons

a survey of current trends in near surface electrical and electromagnetic methods electricalandelectromagnetice emmethodsfornearsurface investigations have undergone rapid improvements over the past few decades besides the traditional applications in groundwater investigations natural resource exploration and geological mapping a number of new applications have appeared these include hazardous waste characterizationstudies precision agricultureapplications archeological surveys and geotechnical investigations the inclusion of microprocessors in survey instruments development ofnewinterpretationalgorithms andeasyaccesstopowerful computers have supported innovation throughout the geophysical community and the e em community is no exception most notable are development of continuous measurement systems that generate large dense data sets efficiently these have contributed significantly to the usefulness of e em methods by allowing measurements over wide areas without sacrificing lateral resolution the availability of theseluxuriantdatasetsinturnspurreddevelopmentofinterpretation algorithms including laterally constrained 1d inversionaswellasinnovative2d and3d inversionmethods taken together these developments can be expected to improve the resolution and usefulness of e em methods and permit them to be applied economically the trend is clearly towarddensesurveyingoverlargerareas followedbyhighly automated post acquisition processing and interpretation to provide improved resolution of the shallow subsurface in a cost effectivemanner

individual particles and martian aeolian action a review abstract evidence for aeolian activity on mars is presented sand sized particles of quartz and basalt were abraded in the laboratory under characteristic earth and martian velocity and pressure conditions and the types of surface features relief were studied with the scanning electron microscope in addition silt and clay produced under these conditions was examined with both scanning and transmission electron microscopy during the experiments electrostatic aggregates of clay and fine silt were produced electrostatic charging by mechanical abrasion seems to have occurred and may be related to the presence of aggregates on mars abrasion appears to be more vigorous under martian than earth conditions given the same mineralogy and particle sizes on the two planets this is probably due to the higher velocities required for martian aeolian activity electrical charging due to particle breakage may be important on mars as deduced from simulation experiments and the data from the viking orbiters and landers additionally experiments with basalt at high abrasion velocities suggests that mineral surfaces on mars may be structurally deformed thus weathering might be more rapid if water were present in the atmosphere and regolith finally during laboratory aeolian abrasion submicron sized quartz particles were produced but material of this type is not found in sediments on earth fine grained sediments should be reexamined to look for these fine particles as the production of clay sized material has important consequences both for erosion and weathering on earth and mars

phytolith transport in sandy sediment experiments and modeling abstract phytoliths are minerals of amorphous silicon dioxide forming in cell lumina and intercellular spaces of living plants because of their morphological specificity and their stability in soils phytoliths have been widely used in paleoenvironmental reconstructions however the mechanisms of phytolith displacement in soil are not well understood which causes uncertainties in the interpretation of phytolith data the objectives of the present study were 1 to determine phytolith transport in sandy sediment under different rainfall and 2 to assess the long term phytolith displacement with moving water by modeling phytoliths extracted from phragmites australis were added to the upper 1 cm layer of columns packed with medium sand two rainfall regimes 1 low frequency irrigation 40 mm 2 times per month and 2 high frequency irrigation 40 mm 8 times per month were simulated over a period of 5 months at the end of this period the distribution of phytoliths was examined in the columns the weighted mean travel distance of phytoliths was 2 7 1 6 mm and 3 7 0 2 mm at the low frequency and high frequency treatments respectively under the high frequency irrigation 22 of the applied phytoliths were leached from the application layer two modeling approaches were tested against the experimental data of the high frequency irrigation treatment the first model was a convection dispersion model with attachment detachment and straining terms in the second model reversibility of straining was additionally taken into account both models resulted in an equally good agreement with observations however the long term predictions calculated with the two approaches were contradictory the first model showed no significant translocation after a period of thousand years whereas the second model predicted that phytoliths would on average be displaced by 19 cm we hence conjecture that our set of observations was not sufficient to distinguish between two models long term experiments on phytolith transport in undisturbed soil are required to ascertain proper modeling of phytolith transport in a sandy soil

phytolith and carbon isotope evidence for late quaternary vegetation and climate change in the southern black hills south dakota abstract analyses of phytoliths and carbon isotopes document change in late quaternary grasslands in the red valley of the southern black hills late pleistocene grassland composition was equivalent to the c3grass parklands of modern central alberta the rise of mixed grassland occurred rapidly between 11 000 and 9000 yr b p early holocene mixed grasslands included both short and tall c4grasses a mid holocene erosional unconformity ca 8000 to 4500 yr b p precludes phytolith or isotope analysis but suggests lack of vegetation and landscape denudation caused by a drier climatic basin wide stability and soil development followed the erosional episode ca 4500 to 3600 yr b p mesic adapted c4panicoid grasses increased during this period of soil development low magnitude fluctuation in the c4 dominated mixed grassland occurred throughout the late holocene 3600 yr b p to present rise in 13c values during the last 1000 yr without corresponding change in phytoliths may indicate a decrease in woodlands caused by increased fire frequency

characterization and palaeoecological significance of archaeological charcoal assemblages during late and post glacial phases in southern france abstract archaeological sites at abeurador and font juvenal have produced extensive charcoal rich horizons the results of the charcoal analysis based on the identification of woody species from anatomical features contribute to the elaboration of plain phases within the development of vegetation in southern france they are presented here in a new diagram and are interpreted as four major vegetation phases from 11 000 14 c yr b p to the recent past in order to interpret the palaeoecological significance of the charcoal assemblages we have used multivariate analysis the data base consists of 42 taxa and 48 archaeological levels the division into four vegetation phases based on analytical interpretation is complemented by the more synthetic interpretation based on correspondence factor analysis cfa the results reveal the patterns of the vegetation history over the last 11 millennia each being characterized by a key plant species

recent developments in shallow depth electrical and electrostatic prospecting using mobile arrays application of mobile electrical and electrostatic quadripoles during the past ten years has allowed a considerable increase in the size of the surveyed areas together with keeping a high spatial resolution and a reduction of the total cost of a survey two new developments of towed arrays are illustrated here 1 a pole pole array pulled by the operator provides a lightweight solution for mapping large surfaces at a unique given depth of investigation as shown by the prospection of the roman british city of wroxeter and 2 a multipole multidepth system allows a 3 d investigation of the ground resistivity as illustrated by the experiments undertaken on the test site of garchy and on the archaeological site of montbaron indre france

geochemistry of the surface sediments of the sulu and south china seas abstract the chemical and mineralogical composition of the surface sediments of the sulu sea a deep hydrographically restricted basin in the indonesian archipelago and the neighbouring area of the south china sea have been examined the aim of the study was to characterize the geochemistry of the sediments of the isolated oxygen deficient basin and to compare them with sediments at equivalent water depths outside the basin as a prelude to a further study of the response of the composition of the sediments to oceanographic changes including possible anoxia during the last glacial maximum the concentrations of most of the chemical constituents in the surface sediments along four transects change markedly with water depth in the sulu sea ss and the south china sea scs thus caco 3 decreases from around 60 by weight in the shallowest samples 800 1000 m to around a few percent in the deepest sample at 4203 m in the scs where the ccd lies at around 4000 m in the ss however the ccd lies much deeper so that the caco 3 contents are still approximately 40 at 4500 m depth organic c also decreases with depth in both basins from values of around 1 2 in the shallowest samples to less than 1 in the deepest samples the ratios of si mg na k co cr cu ni pb rb y zr and zn to al all decrease with increasing water depth because of the change in mineralogy and sediment texture with water depth the p al is higher in shallower water in both areas because of the higher abundance of detrital phosphorite or phosphatized limestone in these sediments the sr al ratio is also higher in shallower water reflecting the supply of aragonitic shell debris from the shallow banks and shelves around the basin the ba al ratio has a maximum at 2000 m depth in the scs due to higher primary production in overlying surface waters whereas it is uniformly low in the ss manganese is also enriched at intermediate water depths in both the ss and the scs because of the presence of oxyhydroxides and this also produces a slight enrichment in mo in the same samples because of their association in this authigenic phase the concentration of i and the i c organic ratio decreases with water depth in both areas due to the higher abundance of fresh marine organic matter at the shallow water sites which scavenges proportionally more i from sea water finally the 13 c organic values tend to decrease irregularly with increasing water depth probably reflecting a higher contribution of terrestrial organic matter in deeper water a discriminant analysis of the full data set reveals that compared with the scs samples the oxygen deficient ss sediments have higher caco 3 contents lower n and s contents and lower i c organic ba al fe al k al pb al rb al ti al v al y al and zn al ratios these contrasts are brought about by the different depths of the ccd differences in the nature of the organic matter and different types of aluminosilicate detritus in the two areas although the i c organic ratios are slightly but significantly lower in the ss which may be due to the low dissolved oxygen contents of the waters of this basin the mn and mo contents and other minor elements that respond significantly to ambient bottom water oxygen levels are not significantly different in the ss and the scs moreover the organic c contents are also indistinguishable in the two areas hence the low bottom water oxygen levels in the ss do not lead to higher organic carbon contents in the surface sediments the composition of sediments in contact with waters having even lower oxygen concentrations should be evaluated in order to conduct a more definitive test of the effect of low oxygen conditions on carbon preservation comparison of glacial interglacial sediment sections from this area must take particular care to separate the effects of source variations on those potentially caused by low oxygen levels

dynamics of production and accumulation of phytolith assemblages in the restinga of marica rio de janeiro brazil abstract the marica restinga located on the eastern part of rio de janeiro state brazil corresponds to one of the few remaining preserved areas of the state s coastal plain this coastline presents two sand barriers separated by a depression where there is a freshwater swamp and different plant communities distributed in areas of high ecological diversity accompanying the local topography and the range of marine spray this paper is a study of the soil phytolith assemblages in the marica restinga with the intent of establishing reference collections for paleoenvironmental studies of this coastal area during the quaternary phytoliths were chosen as proxies but their use for reconstruction of this type of vegetation is pioneer research so it was essential to characterize the phytolith assemblages for each plant community through the identification of the main morphotypes and whether or not they are preserved in coastal depositional environments under the effect of geomorphology and salinity eight plant communities distributed almost parallel to the coastline over sandy barriers lagoonal plain lagoon margin and weathered basement were identified halophile psamophile near the beach two scrub communities one over the holocene barrier and the other over the pleistocene barrier two herbaceous swamps one between the two sand barriers the other behind the pleistocene barrier slack in front of the pleistocene barrier shrubby vegetation on the shore of marica lagoon and dry forest over the weathered pre cambrian basement in general it was found that this type of environment is not very favorable for the formation and accumulation of phytoliths restinga plants did not prove to be large producers of phytoliths except those known as such as in the case of poaceae and cyperaceae it was also observed that the permanence of phytoliths in sediments is strongly influenced by its particle size and organic matter content the largest stocks of phytoliths were found in swamp communities due to the presence of organic matter and low energy dynamics and in dry forests where a process of pedogenesis already occurs despite the low phytolith stocks present in modern assemblages they show a high degree of conservation which enabled significant results for the study of this type of vegetation the calculated phytolith indices tree density and water stress consistently expressed in detail the environment of each community analyzed from the point of view of the type of vegetation cover and the conditions of water availability to plants

biogenic silica storage in soils the role of plants in soil development has become of crucial interest in quantifying global weathering processes on the volcanic reunion island indian ocean a 15 cm thick phytolith rich horizon biogenic opal a developed at the expense of trachytic ashes between 3820 85 and 335 90 yr b p then 97 138 t km 2 yr of sio 2 were biogeochemically recycled from the weathering of parent rocks through a past forest of bamboos nastus borbonicus this rate is in the same range as the present chemical weathering rates of silica in the area considered to be among the highest in the world these results demonstrate that the storage of biogenic silica in soils may be significant and may retard the output of silica to rivers and ocean

bacterial sedimentation through a porous medium numerous previous studies of bacterial transport in groundwaters and to deep aquifers and sediments have either neglected or regarded as insignificant the potential contribution of bacterial sedimentation this study examines the potential significance of sedimentation as a mechanism for bacterial transport a simple model is developed to predict the behavior of particles bacterial or inorganic colloids sedimenting through granular porous media under hydrostatic conditions the model indicates that tortuosity limited sedimentation velocities through porous media consisting of large well rounded grains can proceed at velocities close to 90 that of free sedimentation in water columns when particle grain interactions involve only tortuosity the assumption of neutral buoyancy of bacteria was demonstrated to be invalid through buoyant density measurements on 25 subsurface bacterial strains using percoll density gradient centrifugation an average buoyant density of 1 088 mg m 3 was obtained range from 1 040 to 1 121 mg m 3 the two nonmotile bacterial strains selected for sedimentation experiments were arthrobacter globiformis b672 isolated from the middendorf aquifer 259 m depth and oys3 a streptomycin resistant strain isolated from shallow groundwaters at oyster virginia all experiments were carried out under nongrowth conditions stokes law sedimentation velocities for the two bacterial strains calculated from measurements of buoyant densities and characteristic sizes were 5 8 and 40 mm d 1 respectively direct measurements of free sedimentation of arthrobacter b672 and oys3 through water columns 21 c yielded median velocities of 7 1 and 42 mm d 1 respectively in good agreement with stokes law calculations the arthrobacter b672 and oys3 strains sedimented through saturated sand columns quartz sand 300 420 m diameter under hydrostatic conditions at median velocities of 7 and 17 mm d 1 thus the sedimentation model is consistent with sand column observations on arthrobacter b672 and too simplistic in the case of oys3 bacterial breakthrough by sedimentation exhibited trends consistent with first order attenuation with distance bacterial deposition coefficients for this first order model were in the range of 0 008 0 012 mm 1 surface physical chemical interactions grain and pore size distributions and grain surface microtopography can be very important in controlling the effectiveness of bacterial sedimentation as a transport mechanism this research suggested that if timescales are sufficiently long spanning many generations sedimentation can become a significant mechanism for bacterial transport

the early mesolithic haverbeck site northwest germany evidence for preboreal settlement in the western and central european plain abstract archaeological sites dating from the preboreal are of special interest since they mark the turning point in the transition between the cultures of the late pleistocene and the holocene in spite of their relevance only few sites in the western and central european plain have become known thus providing an inhomogeneous basis for further hypotheses in particular sites in the widespread aeolian landscapes have been neglected for a long time due to their uncertain genesis dating problems and obviously insufficient preservation our investigations of the haverbeck site situated in sandy aeolian substrate seek to enhance knowledge about the preboreal mesolithic the well preserved archaeological spatial technological and functional patterns and the geoarchaeological site formation were studied sedimentological and palaeopedological analyses supported by 14 c and osl dating results revealed that artefacts were deposited during the preboreal on sands which had accumulated during the younger dryas and were reactivated in subsequent periods atlantic subboreal subatlantic in spite of these processes the artefacts remained unimpaired in their relative horizontal positions enabling spatial analyses which show a zonal differentiation and a prevalence of retooling and replacing activities these results offer an insight into spatial and functional differentiations of the local early mesolithic subsistence evidently including particular places for gathering and processing raw material a comparison between the microlithic spectrum left behind and the number of points produced as concluded from the microburins indicates a greater typological differentiation than previously assumed for the early mesolithic the remarkable variability of scraper forms obviously intentionally abandoned in a high number and replaced by new tools emphasizes the strong influence of functional elements on the typological assemblage composition it is suggested that early mesolithic assemblages could display rather functional requirements or tasks performed than significant chronological or regional influences in addition the combination of 14 c osl and pedology helped to reconstruct the aeolian accumulation erosion dynamics and to present a considerable sequence of processes some of which are closely connected with human activities

wind driven particle mobility on mars insights from mars exploration rover observations at el dorado and surroundings at gusev crater 1 the ripple field known as el dorado was a unique stop on spirit s traverse where dust raising active mafic sand ripples and larger inactive coarse grained ripples interact illuminating several long standing issues of martian dust mobility sand mobility and the origin of transverse aeolian ridges strong regional wind events endured by spirit caused perceptible migration of ripple crests in deposits sse of el dorado erasure of tracks in sandy areas and changes to dust mantling the site localized thermal vortices swept across el dorado leaving paths of reduced dust but without perceptibly damaging nearly cohesionless sandy ripple crests from orbit winds responsible for frequently raising clay sized dust into the atmosphere do not seem to significantly affect dunes composed of more easily entrained sand sized particles a long standing paradox this disparity between dust mobilization and sand mobilization on mars is due largely to two factors 1 dust occurs on the surface as fragile low density sand sized aggregates that are easily entrained and disrupted compared with clay sized air fall particles and 2 induration of regolith is pervasive light toned bed forms investigated at gusev are coarse grained ripples an interpretation we propose for many of the smallest linear light toned bed forms of uncertain origin seen in high resolution orbital images across mars on earth wind can organize bimodal or poorly sorted loose sediment into coarse grained ripples coarse grained ripples could be relatively common on mars because development of durable well sorted sediments analogous to terrestrial aeolian quartz sand deposits is restricted by the lack of free quartz and limited hydraulic sediment processing

measuring the relative topographic position of archaeological sites in the landscape a case study on the bronze age barrows in northwest belgium abstract local topography is an important parameter determining the erection of a certain type of site on a certain location in the landscape despite the importance of topography in archaeological landscape research the role of local topography has remained rather unexplored compared to other specific topographic parameters such as slope aspect curvature or visibility therefore three methods to assess the relative topographic position of sites are applied and discussed here the bronze age barrow dataset of northwest belgium acts as the subject for this methodological case study first elevation percentile calculates the area that is lower than the central point within a predetermined neighborhood secondly difference from mean elevation measures the relative topographic position of the central point as the difference between the elevation of this central point and the mean elevation within a predetermined neighborhood and finally deviation from mean elevation calculates the relative topographic position of the central point as the difference from mean elevation divided by the standard deviation of elevation within a predetermined neighborhood these three methods each with their advantages and disadvantages prove to be an added value for archaeological landscape research

settlement and environmental history of a multilayered settlement mound in niederroblingen central germany a multi proxy approach a multi disciplinary palaeoecological approach on a sequence of dated archaeosediments was accomplished the sediments derive from a multilayered prehistoric settlement mound in central germany representing the remnants of a prehistoric village based on the analysis of biological remains and geochemical physical analysis of the settlement layers its environment was reconstructed there is a trend to increasing anthropogenic activities and impact on the environment represented through a rise of indicators for productive surplus from the early neolithic 5300 4900 bc until the roman times 400 ad during the early neolithic shifting flat settlements were situated in a locally opened landscape the immediate surrounding of the floodplain was used by the settlers for their economic requirements e g wood from the riparian forest after a hiatus of ca 1900 years a multilayered settlement mount rose from late neolithic times 3000 bc to roman times since the middle bronze age approximately 1500 bc the riparian forest was obviously replaced by agricultural fields and meadows and henceforward the hinterland used by the settlers probably grew in size the continuing demand of wood was maintained by the acquisition of more distant sources the onset of house constructions substituting wood by loam wattle and daub might be a possible societal response to this shortfall this is reflected in the growing thickness and composition of the settlement layers as well as in the archaeological record e g tumbled wattle and daub house walls the rising of the groundwater table and the start of severe floods of the adjacent river helme during pre roman iron age approx 800 100 bc might reflect a geomorphological response to the increased land use intensity at a regional scale

testing soil phytolith analysis as a tool to understand vegetation change in the sagebrush steppe and pinyon juniper woodlands of the great basin desert usa better biological proxy methods are needed to understand changes in arid ecosystems over the recent past our objective in this study was to examine the utility of soil phytolith analysis to reflect vegetation changes over the past 200 years from the end of the little ice age to present the sensitivity of phytoliths to record vegetation changes for this time period was tested by sampling in locations where vegetation changes were known to have occurred based on human records we used extraction weights to test for the trend in reduction of grasses and increase in woody vegetation over time we used the relative abundance of soil phytolith morphotypes from native versus introduced grasses to look for the increase in non native grasses then we examined the phytolith assemblages from soils in a continuous core sampling method with 1 cm increments extraction weights decreased by half from the surface to little ice age layers and may reflect increasing pinyon juniper woodland cover the relative abund

on the use of modern tropical domed peats as analogues for petrographic variation in carboniferous coal beds abstract a series of peat cores were collected along four transects in indonesia and malaysia for the purpose of developing modern analogues for the development of bright and dull lithofacies in coal fig 1 each deposit consists of a number of well defined zones of peat which reflect the original plant types and the degree of degradation these components vary with respect to their position within the peat body for example the sumatran deposit consists of predominantly of moderately decomposed woody peat with thin interbeds of coarser peat which become thicker in the central upper portion of the deposit fig 2 in contrast the cross sections from the malyasian transects show more distinct stratification in peat types and thicker coarse peat zones in the center of the deposit fig 3 presumably as the coast progrades the near coastal peats are being progressively overlain by inland forest peats as evidenced in the more mature deposits landward anderson 1964 although comparisons of bright to dull trends in coal i e decreasing vitrain band thickness and or vitrinite content have been made to the internal strata of the peat on the basis of the decreasing distribution of large wood fragments upwards within the deposits esterle and ferm 1986 esterle and tie in press the premaceral composition of these peats has not been fully established for this purpose a series of samples from each deposit was selected for petrographic examination in reflected light using coal petrologic methods wet peat samples were first frozen in liquid nitrogen lyophilized and finally vacuum impregnated with a low temperature bioplastic impregnated samples were then set up as blocks ground and polished for petrographic examination using brown coal terminology preliminary results show striking differences between the distinctly domed peat at tg pasir in sarawak and the relatively flat topped peat in jambi sumatra although the composition of both deposits is dominated by macerals of the huminite group which show relative decreases in the amount of structured textinite and humotelinite downhole and towards the margins of the deposit internite contents vary differently in the sarawak domed deposit inertinite macerals are virtually absent throughout and only occur in low percentages the results of preliminary petrographic examination suggest that modifications are needed for the usage of modern domed peat deposits as analogues for petrographic variation in carboniferous coal beds although the decrease in the size and amount of wood fragments in modern domed peat deposits supports a dulling up or decreasing vitrain band thickness model for coal on a megascopic scale the petrographic data show contradictory evidence

phytolith assemblages as a promising tool for reconstructing mediterranean holocene vegetation the reliability of phytolith assemblage analysis for characterizing mediterranean vegetation is investigated in this study phytolith assemblages are extracted from modern and buried holocene soils from the middle rhone valley france the relation between modern phytolith assemblages and the surrounding vegetation as well as between fossil assemblages and contemporaneous vegetation already reconstructed through other proxies is discussed we demonstrate that the main northwestern mediterranean biomes are well distinguished by soil phytolith assemblage analysis in particular the density of pine and nonconiferous trees densities expressed relatively to the grass cover and the overall degree of opening of the vegetation appear well recorded by three phytolith indexes north mediterranean vegetation changes during the holocene period mainly tree line shifts pine wood development and deforestation are poorly documented due to the scarcity of proxy preserving sites phytolith assemblage analysis of soils buried soils and sediments appears to be a promising technique to fill this gap

reconstructing late holocene palaeoenvironments in bangladesh phytolith analysis of archaeological soils from somapura mahavihara site in the paharpur area badalgacchi upazila naogaon district bangladesh palaeoenvironmental reconstruction based on phytolith analysis of late holocene aged soils in and around the somapura mahavihara archaeological monastery site in the paharpur area badalgacchi upazila of naogaon district in northwestern bangladesh was undertaken results indicate five climate zones marked by alternatively cool and temperate events the phytolith assemblages of zones 1 3 and 5 are clearly characterized by a higher proportion of pooideae phytoliths the climate indices for these zones are all greater than 50 indicating cooler climatic conditions in contrast the phytolith assemblages of zones 2 and 4 are typified by a higher proportion of panicoideae phytoliths their climate indices are 42 and 44 respectively indicating the presence of a warmer more temperate climate in general the dominance of grasses over broad leaved trees throughout the sequences suggests that generally cool to temperate and dry conditions with some cyclical variability persisted around paharpur and the surrounding region throughout the pala dynasty from ad 730 to 1080 the question of whether these shifts in vegetation might be linked with el nino southern oscillation events and whether these might in turn have cultural responses is raised

an opal phytolith and palynomorph study of extant and fossil soils in kansas u s a abstract soils from three plant communities in kansas shortgrass prairie tallgrass prairie and deciduous forest were analyzed for opal phytoliths pollen grains and fungal spores these data were used to correlate vegetation type with phytolith and palynomorph deposition the results were applied to the study of a paleosol to determine the vegetation and ecological conditions prior to burial statistical analyses of the data show that the phytolith composition differs significantly among the three extant soils pollen analysis failed to differentiate between tallgrass and shortgrass prairie because the pollen can not be accurately attributed to the different grass taxa that are characteristic of these vegetation types pollen analysis however distinguished woodland sites from the prairies because of the abundance of easily recognizable pollen of woody plants the comparison of the extant soils to the paleosol show that the plant community prior to burial may have been a cool season grassland the results demonstrate the importance of combined phytolith and pollen analysis in the characterization of grasslands

taphonomical aspects of silica phytoliths in the loess sediments of the argentinean pampas abstract although pampean loess and pedostratigraphy processes in the pampas have been widely studied phytoliths observed in these sediments have been only mentioned without further quantitative or qualitative studies the present work is a first step towards an understanding of the environmental significance of loess phytolith datasets and their validity for palaeoenvironmental reconstructions and to comprehend the environmental conditions of loess formation the research focused on the taphonomy of loess phytoliths investigating the loess morphological and sedimentological characteristics variability in the qualitative and quantitative assemblage composition the phytolith frequency and were also phytolith extraction techniques the results highlight that the phytolith pool of loess deposits still retains information about the past vegetation and phytolith analysis from these deposits can be a useful exercise to further comprehend past climatic and environmental conditions under which loess palaeosol sequences formed

phytolith analysis and reconstruction of palaeoenvironment at the nabokri valley plain buyeo korea abstract the soil profile between 12 0 and 14 0 m a s l was deposited at the nabokri valley plain buyeo korea from approximately 6000 bp to the present through phytolith analysis of 20 samples collected at 10 cm intervals five phytolith assemblage zones pazs are identified based on the number of various types of phytoliths and occurrence of specific families adapting to the particular climates this study yields the climatic indices reconstructs the paleoclimates and estimates the human activities during the reconstructed period the five pazs are well correlated to the chronology of sedimentary layers and construction periods of the artifacts at the archaeological excavation the buyeo area was temperate and wet during the neolithic age paz i and there is no phytolith evidence of vegetation change by humans the climate can be characterized as temperate and wet during the early bronze age paz ii but then cooling later during this period agricultural activities began with the panicoideae including oryza sativa in the early iron age the climate became warmer the climate during the proto three states age paz iii since 2000 bp was variable and species such as o sativa and panicoideae were actively cultivated the three states age can be characterized by variable climates similar to the proto three states age the ic climate index and iph humidity aridity index values indicate that the climates were first wet and then became drier agricultural activities are identified from the bronze age paz ii through three states age and joseon dynasty paz iv based on the presence of cultivation layers as well as specific phytolithic indicators of agriculture the uppermost layer paz v shows no evidence of agricultural activities due to the significant decrease in the number of phytoliths perhaps from recent abandonment

properties of electrostatic aggregates and their possible presence on mars abstract experiments indicate that at the high wind velocities characteristic of portions of the martian surface sand sized particles will break down to silt and clay which will then inevitably form sand sized aggregates basalt and olivine aggregates held together by electrostatics were produced in an eolian abrasion device and their mass properties studied it was difficult to examine aggregates after formation as they separate and reform with very little handling since electrostatic binding forces are quite weak it is shown that aggregates range from 60 to more than 600 m in diameter that they generally are spheroidal in shape and become more elongate with increasing size and that they tend to be layered with the inner portions more tightly bound than outer layers after about one and one half years some aggregates lose their charge which is replaced with moisture the aggregates retain their original sizes and shapes none of the properties of electrostatic aggregates so far investigated are incompatible with the presence of these materials on mars

the response of a three dimensional magnetic and conductive body in shallow depth electromagnetic prospecting summary the study of the abilities of an e m apparatus for shallow depth prospecting necessitates that we analyse the experimental data through theoretical modelling a 3 d model for a magnetic and a conductivity contrast is presented here applied to the slingram type sh3 case intercoil spacing equal to 1 5 m and frequency to 8 khz it shows that this apparatus is roughly equivalent to the classical wenner 1 m array and is more sensitive than magnetic prospection to susceptibility changes occurring in the soil above 60 cm depth the 3 d model will also be very valuable for the conception of improvements in the apparatus

a fluvial record of the mid holocene rapid climatic changes in the middle rhone valley espeluche lalo france and of their impact on late mesolithic and early neolithic societies abstract this multi proxy study of a small floodplain in the rhone catchment area at the northern edge of the mediterranean morphoclimatic system provides valuable information concerning the impact of mid holocene climate variability 8 5 7 0 ka and the effects of two rapid climatic changes 8 2 and 7 7 7 1 ka on an alluvial plain its basin and the first farming societies of the rhone valley around 7 7 7 1 ka the combined effects of 1 a strong rate of change in insolation and 2 variations in solar activity amplified marine and atmospheric circulation in the north west atlantic bond event 5b which imply continental hydrological soil and vegetation changes in the small catchment area for this period strong fluctuations in the plant cover ratio have been identified related to a regime of sustained and regular fires as well as abundant erosion of the hill slopes and frequent fluvial metamorphoses which led to braiding of the watercourse in this floodplain there are few data available to evaluate the impact of natural events on prehistoric communities this continental archive offers clear multi proxy data for discussion of these aspects having 4 cultural layers interbedded in the fluvial sequence 1 late mesolithic 3 cardial epicardial earlier data indicate the difficulty in recognizing such cultural features in the low alluvial plains of southern france during the mesolithic early neolithic transition which should lead to caution when developing settlement models for this period