evidence for a late precambrian caldera in boston massachusetts ash flow tuff in the stony brook reservation contains clasts as much as 450 m long the pyroclastic matrix of this breccia and the large size of its clasts are characteristic of megabreccias found in terrains of ash flow volcanism and caldera collapse the breccia of the stony brook reservation is intruded by shallow level westwood granite suggesting that both caldera collapse and magmatic resurgence were important processes in the history of this part of the late precambrian plutonic volcanic terrain in southeastern new england

sourcing geochemically identical obsidian multiscalar magnetic variations in the gutansar volcanic complex and implications for palaeolithic research in armenia abstract in obsidian rich armenia one of the most archaeologically significant obsidian resources is the gutansar volcanic complex gvc numerous palaeolithic sites across armenia consist of little more than deposits of obsidian tools and debris and within the hrazdan gorge the vast majority of artifacts is crafted from gvc obsidian for example about 93 of the lithic assemblages from the lower palaeolithic site of nor geghi 1 and the middle palaeolithic site of lusakert cave 1 are gvc obsidian although erupted from multiple volcanic centers gvc obsidians are geochemically identical and cover an area more than 70 km2 for studies seeking to reconstruct movements of palaeolithic hunter gatherers throughout the local landscape the expansive gvc is problematic geochemically identical obsidians dominate the foraging territories of sites within and near the complex here we explore the potential of obsidian magnetic properties to reveal hitherto unobservable patterns in gvc obsidian utilization with the ultimate goal of elucidating palaeolithic behavioral patterns our results show that magnetic properties vary over multiple scales within the gvc allowing obsidian sourcing to become multiscalar these measurements are rapid inexpensive and entirely nondestructive for small artifacts measuring a few basic magnetic properties enables us to distinguish geochemically identical obsidians from three eruptive centers and potentially to attribute artifacts to specific quarrying sites recognize changes in provisioning strategy and estimate a minimum number of cores represented by a lithic scatter

geophysical imaging of alpine rock glaciers slope instabilities caused by the disappearance of ice within alpine rock glaciers are an issue of increasing concern design of suitable counter measures requires detailed knowledge of the internal structures of rock glaciers which can be obtained using geophysical methods we examine benefits and limitations of diffusive electromagnetics geoelectrics seismics and ground penetrating radar georadar for determining the depth and lateral variability of the active layer the distributions of ice and water the occurrence of shear horizons and the bedrock topography in particular we highlight new developments in data acquisition and data analysis that allow 2 d or even 3 d structures within rock glaciers to be imaged after describing peculiarities associated with acquiring appropriate geophysical datasets across rock glaciers and emphasizing the importance of state of the art tomographic inversion algorithms we demonstrate the applicability of 2 d imaging techniques using two case studies of rock glaciers in the eastern swiss alps we present joint interpretations of geoelectric seismic and georadar data appropriately constrained by information extracted from boreholes a key conclusion of our study is that the different geophysical images are largely complementary with each image resolving a different suite of subsurface features based on our results we propose a general template for the cost effective and reliable geophysical characterization of mountain permafrost

new pieces the acquisition and distribution of volcanic glass sources in northeast china during the holocene abstract little is known about the diversity of volcanic glass sources used in prehistoric northeast china although preliminary research established the presence of a number of sources in archaeological sites from this area the exact location of these sources was not known jia et al 2010 a recent geoarchaeological survey of three source areas and new data derived from portable x ray fluorescence elemental analysis pxrf has revealed not only the location and use of two new geological sources in northeast china but also extended our understanding of the geologic context of volcanic glass from tianchi paektusan volcano the major geological source of volcanic glass in northeast china furthermore understanding the geological history of these new sources clarifies why they were only found in archaeological sites dated to the holocene

environment and collapse eastern anatolian obsidians at urkesh tell mozan syria and the third millennium mesopotamian urban crisis the early to middle bronze age transition in northern mesopotamia has received great attention for the apparent concurrence of aridification deurbanisation and the end of the akkadian empire around 2200 bce our understanding of the crisis has been almost exclusively shaped by ceramics demography and subsistence exchange and the associated social networks have been largely neglected here we report our sourcing results for 97 obsidian artefacts from urkesh a large urban settlement inhabited throughout the crisis before the crisis six obsidian sources located in eastern anatolia are represented among the artefacts such a diversity of eastern anatolian obsidians at one site is hitherto unknown in mesopotamia it implies urkesh was a cosmopolitan city with diverse visitors or visitors with diverse itineraries during this crisis however obsidians came from only two of the closest sources two to three centuries passed before varied obsidians reappeared even when an obsidian source reappears the raw material seems to have come from a different collection spot we discuss the likely exchange mechanisms and related social networks responsible for the arrival of obsidians at urkesh and how they might have changed in response to climatic perturbations and regional government collapse

using two and three dimensional georadar methods to characterize glaciofluvial architecture abstract the threat of pollution in the shallow subsurface has led to an increasing need to understand how complex heterogeneities in gravel aquifers influence groundwater transport to characterize these heterogeneities we have conducted extensive two dimensional 2 d and three dimensional 3 d ground penetrating radar gpr or georadar surveys in two quarries within the rhine valley of northeastern switzerland the quarries comprised gravel and sand deposited in a proglacial braided river system that followed the maximum wurm stage glaciation after the surveys the terrace walls beneath the two study sites were photographed as they were being excavated by combining information extracted from the 2 and 3 d georadar images with the outcrop photographs it was possible to correlate georadar facies with the various glaciofluvial architectural elements the dominant elements were scour pools formed at or near the confluences of two stream channels and horizontally bedded and massive gravel sheets deposited during moderate to high water flow conditions and exposed during low flow conditions architectural elements were generally elongated parallel to the mean flow directions of the ancient river system variations in the strike of their long axes reflected lateral and vertical changes in the local flow direction time slices showed structural trends not evident on 2 d georadar images and photographs data interpretation was quicker more complete and less ambiguous when georadar facies analyses were based on a combination of georadar vertical profiles and time slices than when based on georadar vertical profiles alone

semiautomated georadar data acquisition in three dimensions under favorable conditions georadar techniques can provide vivid images of the shallow subsurface 10 50 m although the significant advantages of 3 d georadar surveying strategies are well documented they generally require much greater expenditures than traditional 2 d approaches we introduce an efficient semiautomated 3 d georadar acquisition and processing scheme that does not jeopardize data quality a standard georadar acquisition unit is integrated with an innovative self tracking laser theodolite with automatic target recognition capabilities georadar and coordinate data are recorded simultaneously as the georadar antennae are transported steadily across a survey area while tracking a target prism mounted between the antennae the theodolite provides real time coordinate information with high accuracy in all directions at 1 m s moderate walking speed the coordinates are determined to better than 0 04 m and at 3 m s they are better than 0 07 m subsequent to acquisition semiautomati

chemical and spectroscopic study of nephrite artifacts from transbaikalia russia geological sources and possible transportation routes abstract the first results of the complex studies of sources of the nephrite raw material that was used by ancient residents of the baikal region russia are discussed non destructive chemical and physical spectroscopic methods x ray fluorescence spectrometry raman and photoluminescence spectroscopy were used to determine the chemical and mineral composition and luminescence properties of nephrite aggregates possible regions and deposits of nephrite provenance for several neolithic artifacts are estimated khara nurskiy massif dzhidinsky district and vitim river localities ospinskoye deposit it was estimated that the ancient transportation routes of nephrite could be exceptionally long up to several hundreds of kilometers

moving sources a preliminary study of volcanic glass artifact distributions in northeast china using pxrf recent studies have highlighted the long distance transport of obsidian from the paektusan tianchi or baitoushan in chinese volcano on the border between china and north korea to eastern russia and korea but little is known about the role of the local population in the production and movement or exchange of this important raw material this paper addresses this data lacuna by presenting sourcing results of 440 artifacts from 18 late paleolithic sites located in northeast china a portable xrf enabled rapid non destructive characterization of samples the results show that although paektusan obsidian was widely transported throughout northeast asia material from at least three other sources was also used in particular we highlight the significance of basaltic glass artifacts with the same geochemistry as sources found in the primorye region of far east russia in sites from northeast china this result indicates a two way movement of volcanic glass artifacts between primorye and the northeast of china rather than a unidirectional long distance exchange system originating from paektusan volcano

3 d ground penetrating radar applied to fracture imaging in gneiss three dimensional ground penetrating radar georadar techniques suitable for geological engineering applications have been developed and tested initial experiments were conducted on the floor of a quarry in southern switzerland from which ornamental gneissic rock is extracted during a brief two day period constant offset georadar data were recorded over a 650m2 area with a grid cell size of 0 1 m 0 2 m georadar velocities were estimated from the results of expanding spread surveys all georadar data and associated geometry files were recorded automatically in seismic industry formats the experimental georadar data set was processed image enhanced and interpreted using 3 d seismic reflection software operating on a workstation arbitrary vertical sections time slices 3 d images and animated movies in which the observer travels through the entire data volume were constructed from the resultant migrated georadar data semi automatic tracking routines allowed continuous subhorizontal reflectio

ten seconds in the field rapid armenian obsidian sourcing with portable xrf to inform excavations and surveys armenia has one of the most obsidian rich natural and cultural landscapes in the world and the lithic assemblages of numerous palaeolithic sites are predominantly if not entirely composed of obsidian recent excavations at the middle palaeolithic cave of lusakert 1 recovered on average 470 obsidian artifacts daily after sourcing more than 1700 artifacts using portable xrf pxrf in our field house our team sought to shift pxrf based obsidian sourcing into the field itself believing that the geological origins of artifacts would be useful information to have on site during an excavation or survey despite increasing use of portable instruments previous studies have principally focused on collections in museums and other archives and as a result obsidian sourcing has remained embedded in post excavation studies one critical factor in the uptake of obsidian sourcing in the field is the time needed to measure each artifact frequently 2 6 min in previous studies here we report our two methods of obsidian sourcing including source matching done automatically by the pxrf instrument s onboard software in only 10 s our tests with armenian geological specimens and palaeolithic artifacts demonstrate the high efficacy of our two methods which are sufficiently fast to become syncopated with our excavation and survey activities by reducing measurement times from a mode of 300 s in recent studies to just 10 s here we show how and why to shift pxrf based obsidian sourcing from the context of white lab coats to that of muddy boots

the use of lithic raw materials during the upper paleolithic in eastern china a focus on microblade industries abstract during the upper paleolithic many sites with microblade industries were distributed across northeastern china and the north china plain in eastern china based on the composition of lithic raw materials lrms and the site distributions of microblade industries this study defined five territories of human groups in two regions of china 1 the western changbai shan mountains mount paektu and song nen plain in northeastern china and 2 the southern yanshan mountains yi shu river basin and western huang huai plain in the north china plain in northeastern china high quality lrms including various types of igneous rock and obsidian were used in combination with local lrms such as flint and agate based on the distribution range of high quality lrms the territories of human groups in that region are estimated at 300 450 km it is believed that residential systems were established for the long distance transport of lrms and the long distance movement of human groups one such system included microblade technology based on biface and flake blade reduction systems in contrast the territory of human groups in the north china plain was small with an area estimated at 100 230 km given the numerous small sites in that region it is believed that human groups moved frequently within their territories because they were highly mobile and dependent on local lrm sources e g flint near their occupation sites human groups might have employed various microcore reduction systems to produce microblades even from limited lrms preliminary conclusions suggest that the divergent activities of late upper paleolithic human groups in eastern china could reflect variations in regional economic strategies and ecological environments between the last glacial maximum and the younger dryas

non destructive geochemical and magnetic characterisation of group xviii dolerite stone axes and shaft hole implements from england thirty five polished stone axes and shaft hole implements which had been previously assigned by petrographic partially destructive study to group xviii assumed to be from the whin sill dolerite source in northern england were characterised non destructively using a combination of portable x ray fluorescence analysis pxrf and magnetic susceptibility measurements all the implements were compared with the whin sill and with other petrologically and or visually similar rock sources in the north of england and in scotland using a database of chemical elements constructed from the published literature and statistical atypicality testing twenty nine of the implements are good matches for the whin sill as expected but three do not match whin sill rocks and may therefore need to be re assessed as members of group xviii a further three implements have ambiguous characteristics perhaps as a result of surface weathering one axe an axe hammer and an adze that had not previously been assigned to implement groups were also analysed as a test of the robustness of the non destructive methods all three implements could be distinguished from group xviii on the basis of chemical and magnetic characteristics most of the distribution of group xviii implements is best explained by the opportunistic use of glacial erratics rather than trade from the primary source possible alternative sources for the non group xviii implements include the scottish old red sandstone age lavas which could also have been obtained as erratics the chemical and magnetic characteristics established in this paper provide a non destructive alternative to thin section study of potential group xviii artefacts

imaging rainfall drainage within the miami oolitic limestone using high resolution time lapse ground penetrating radar 1 the vadose zone of the miami limestone is capable of draining several centimeters of rainfall within a fraction of an hour once the water enters the ground little is known about the flow paths in the oolitic rock a new rotary laser positioned ground penetrating radar gpr system enables centimeter precise and rapid acquisition of time lapse surveys in the field two dimensional 2 d gpr time lapse surveying at a 3 min interval before during and after rainfall shows how buried sand filled dissolution sinks efficiently drain the bulk of the rainwater hourly repeated 3 d imaging of a dissolution sink in response to surface infiltration shows how the wetting front propagates at a rate of 0 6 1 2 m h traversing the 5 m thick vadose zone within hours at the same time some of the water migrates laterally into the host rock guided by stratigraphic unit boundaries average lateral propagation measured over a 28 hour period was of the order of 0 1 m h on a seasonal time frame redistribution involves the entire rock volume comparing 3 d surveys acquired after wet summer and dry winter conditions shows good gpr event correspondence but also time shifts up to 20 ns caused by the change of overall water content within the vadose zone high precision time lapse gpr imaging can therefore be used to noninvasively characterize natural drainage inside the vadose zone ranging from transient loading to seasonal variation

3d gpr reveals complex internal structure of pleistocene oolitic sandbar active oolitic sandbars like those in the bahamas figure 1 exhibit complex internal architecture with a multitude of stacked sedimentary structures ooids are round carbonate coated grains that form in tropical climates the internal anatomy of carbonate sandbars is often too complex to be captured in one and two dimensional data outcrops cores and 2d geophysical profiles provide a limited vertical view of the geologic record depositional processes are confined to the momentary subhorizontal boundary surface between sediment and water or air vertical 2d views limit the visibility of features developed on subhorizontal surfaces making interpretation of 3d internal anatomy and reconstruction of related depositional parameters difficult closely spaced 3d data are needed to accurately map sedimentary structures and improve fluid flow modeling used in water and hydrocarbon resource management 3d reflection seismic imaging has successfully been used to delineate oolitic bars in sub surface oil field

pxrf characterisation of obsidian from central anatolia the aegean and central europe the obsidian sources of central anatolia the aegean and central europe have been studied in detail over the past 50 years various analytical techniques have been employed to discriminate artefacts from each of these and to reconstruct their zones of distribution this paper presents a pxrf method that allows mass sampling of artefacts focusing on three neighbouring regions particularly where these zones overlap successful discrimination of the obsidian source for products could be achieved using three dimensional scatter plots of trace elements rb sr zr pxrf can thus be appreciated as a powerful tool in the region enabling non destructive on site analyses in contexts where the export of artefacts is often difficult if not impossible the ability to rapidly process large assemblages also has major implications for generating data sets of sufficient resolution to transform archaeological interpretation

integration of sedimentology and ground penetrating radar for high resolution imaging of a carbonate platform ground penetrating radar has not been applied widely to the recognition of ancient carbonate platform geometries this article reports the results of an integrated study performed on an upper jurassic outcrop from the south east paris basin where coral bioherms laterally change into prograding depositional sequences ground penetrating radar profiles illustrate the different bedding planes and major erosional unconformities visible at outcrop a ground penetrating radar profile conducted at the base of the cliff displays a palaeotopographic surface on which the outcropping bioherms settled the excellent penetration depths of the ground penetrating radar 20 m with a monostatic 200 mhz antenna images the carbonate platform geometries ranging between outcrop workscale a few metres and seismic scale several hundreds of metres this study supports recent evidence of icehouse conditions and induced sea level fluctuations controlling the upper jurassic carbonate production

characterization of new zealand obsidian using pxrf abstract new zealand has some of the most active areas of rhyolitic volcanism in the world and this has produced numerous obsidian sources in the northern half of the north island in total archaeologists have recognized 27 named locations from which obsidian can be obtained scattered across 4 geological source regions shortly after colonization in the late 13th century ad polynesian settlers began transporting this material some thousands of kilometers throughout the country and across the sea in small quantities to distant neighbors in the kermadecs and chatham islands although considerable research has been conducted on obsidian sourcing in new zealand the complexity of geochemical source discrimination and the lack of a practical method of non destructive geochemical analysis has hindered progress we present the results of our use of pxrf to provide geochemical data on new zealand obsidian sources and to compare the use of discriminant analysis and classification tree analysis to discriminate among sources and attribute archaeological samples to sources our research suggests that classification tree analysis is superior to discriminant analysis in sourcing studies a large case study using an important settlement phase site s11 20 from the auckland region demonstrates the utility of the methods and the results support a model of high degrees of mobility and interaction during the early settlement of new zealand

ground penetrating radar characterization and porosity evolution of an upper pleistocene oolite capped depositional cycle red bays northwest andros island great bahama bank abstract linkages among surface sediments depositional processes geomorphic forms stratigraphic architecture and pore distribution in bahamian sand bodies and oolite capped depositional successions have been characterized in recent studies an understanding of how these parameters especially porosity are preserved or modified in the eogenetic environment is essential in bridging the gap between modern and ancient analogs two complementary 3d 200 mhz and 400 mhz ground penetrating radar surveys and three shallow cores reveal that the uppermost part of the upper pleistocene marine isotope stage 5e lucayan formation at red bays andros island great bahama bank comprises a single 6 m thick upward shallowing parasequence six radar packages p1 p6 bounded by radar surfaces s1 s6 have been identified in the two 3d radar volumes the stratigraphic succession indicates development of a burrowed backshoal lagoon during early flooding of the bank top followed by deposition of flood tide driven low angle sheet sands and sigmoidal subaqueous dune deposits as the shelf margin sand shoal moved bankward as a function of continued sea level rise constructional accommodation on the front of the prograding subaqueous dune in the northwest part of the survey area and erosional accommodation created by downcutting of a shallow tidal channel into the upper part of the subaqueous dune depositional unit in the northeast part of the study area were filled with peloid and ooid dominated carbonate sands as sea level stabilized the uppermost radar package is a thin 0 15 to 0 55 m partially calichified carbonate sand sheet that mantles the entire survey site and that reflects late highstand and fall of sea level exposure of the studied interval to meteoric vadose diagenesis over the past 100 000 years has resulted in partial stabilization of the largely aragonitic precursor sediment through selective partial dissolution of aragonitic grains mainly ooid cortical layers peloids and mollusk shells accompanied by precipitation of patchily distributed low magnesium calcite cement core data demonstrate a relationship between stratigraphically controlled sedimentological attributes diagenesis and pore distribution three distinctive zones of porosity were present upon deposition a lower zone of relatively high interparticle porosity 21 3 to 33 2 in the medial part of p1 a low porosity zone

full resolution 3d radar stratigraphy of complex oolitic sedimentary architecture miami limestone florida u s a abstract at the field scale m s to 100 s m it is often difficult to define the true three dimensional form of depositional units or facies within sediments or sedimentary rocks due to inherent spatial bias in traditional data sources such as outcrops and cores full resolution 3d ground penetrating radar gpr surveying has the potential to overcome this problem southwest of miami paleotopography on the upper pleistocene miami limestone formation indicates the former presence of a large oolitic barrier bar backed by extensive ooid shoals data from three closely spaced cores and two large outcrops on the barrier bar allow initial subdivision of the miami limestone in to a lower mottled oolitic facies and an upper bedded oolitic facies however detailed correlation between the cores and outcrops is problematic due to spatial aliasing a 250 mhz full resolution 3d gpr data set was collected over an area of 45 m 24 m that encompassed the location of the three cores depth of radar wave penetration was around 6 m and both horizontal and vertical resolution was approximately 0 1 m for the 6500 m3 rock volume such that the upper bedded oolitic facies was imaged without spatial aliasing radar surfaces and intervening radar facies define two main radar package types low angle sheet and sigmoidal the low angle sheet radar packages are interpreted as oolitic shoal deposits consisting of tidal bars covered by ebb orientated straight crested sand waves the overlying sigmoidal radar packages record barrier bar formation through alongshore progradation comparable sedimentary successions from both pleistocene and modern deposits in the bahamas suggest that the three evolutionary stages recorded for the miami limestone are typical of many transgressive ooid shoal complexes

sources of archaeological obsidian on sakhalin island russian far east abstract instrumental neutron activation analysis was performed on 79 obsidian tools and flakes from 35 sites on sakhalin island dating from upper paleolithic c 19 000 bp to early iron age c 2000 800 bp due to the absence of volcanic glass on sakhalin island raw materials from the nearest obsidian sources on hokkaido island such as oketo shirataki tokachi mitsumata and akaigawa were also analysed a strong correlation between the chemical compositions of obsidian artefacts from sakhalin and volcanic glass sources from hokkaido was discovered in particular the oketo and shirataki sources were used for tool manufacturing throughout all of sakhalin island s prehistory the distances between sources and archaeological sites range from 200 1000 km the intensive exchange of raw materials continued and even intensified after the appearance of the la perouse soya strait between hokkaido and sakhalin about 10 000 8000 bp the sakhalin island populations were deeply involved in the obsidian exchange network centered on hokkaido

non destructive pxrf analysis of museum curated obsidian from the near east abstract non destructive pxrf has the potential to expand sample populations of archaeological provenancing studies by facilitating access to museum collections of artefacts in this study we use museum curated obsidian for the sites of tell brak mersin yumuktepe and tell arpachiyah and geological obsidian samples from central turkey to demonstrate that non destructive pxrf is comparable to other techniques in differentiating between near eastern obsidian sources secondly we use multivariate analysis to evaluate whether non destructive pxrf is sufficiently accurate and precise to enable comparison with legacy datasets from previous analysis using pixe and icp ms multivariate analyses show that instrumental offsets between the results from pxrf and other analytic techniques are less than source to source variation typical for most anatolian obsidian outcrops and pxrf identified geochemical groups are directly comparable to legacy datasets non destructive pxrf analysis indicates that during the chalcolithic east gollu dag and nenezi dag continued to be the major sources of obsidian to communities in central anatolia and the bingol range and mountains surrounding lake van supplied sites east of the levant variations in the analysed assemblages suggest a number of obsidian exchange networks existed during this period

testing the accuracy of portable x ray fluorescence to study aztec and colonial obsidian supply at xaltocan mexico abstract this article demonstrates the accuracy of non destructive portable x ray fluorescence p xrf for the study of obsidian in central mexico obsidian sources were identified for a sample of 103 artifacts from the site of xaltocan which spanned the rise and fall of the aztec empire and the first centuries of spanish colonial rule ad 900 1700 sources were assigned by comparing p xrf measurements with previously published source data and were verified using the standard techniques of laboratory xrf l xrf and instrumental neutron activation analysis inaa additional tests of potentially confounding factors show that neither length of read time presence of surface residue nor incomplete detector coverage due to small artifact size compromised our ability to attribute sources to artifacts concave surfaces did decrease the accuracy of readings because of the greater distance between the artifact and the detector our results provide new insight into the stability of supply networks and markets well into the colonial period as well as the homogenizing tendencies of the aztec market system

delineation of macroporous zones in the unsaturated portion of the miami limestone using ground penetrating radar miami dade county florida summary the atlantic coastal ridge in dade county is an ooid shoal formed during the late pleistocene the ridge is composed of the eogenetic karst miami limestone characterized by a heterogeneous distribution of porosity that can manifest as large touching vug macroporous features with sizes in the meters and tens of meters direct evidence for the presence of such large dissolution features is only visible when exposed to the surface which may be problematic in urbanized areas for that reason it is critical to detect any potential precursors for such dissolution features at the subsurface level the purpose of this study was to investigate the ability of ground penetrating radar to detect areas of macroporosity by quantifying changes in electromagnetic wave velocity and relate them to changes in porosity after application of the complex refractive index model crim in order to constrain volumetric water content vwc in the crim an experiment using miami limestone samples was designed to understand 1 the range of typical vwcs and 2 the effect of capillary fringe on water table elevation the results show several areas where increases in em wave travel time associated with contrasts in porosity exceeding 40 cannot be explained by changes in vwcs typically shown in the miami limestone this study may help understand porosity variability in the unsaturated part of the miami limestone and if expanded to larger scales may aid groundwater flow models by better capturing distributions of macroporous areas that may contribute to direct recharge of the biscayne aquifer

identifying causes of ground penetrating radar reflections using time domain reflectometry and sedimentological analyses ground penetrating radar gpr is a geophysical technique widely used to study the shallow subsurface and identify various sediment features that reflect electromagnetic waves however little is known about the exact cause of gpr reflections because few studies have coupled wave theory to petrophysical data in this study a 100 and 200 mhz gpr survey was conducted on aeolian deposits in a quarry time domain reflectometry tdr was used to obtain detailed information on the product of relative permittivity er and relative magnetic permeability lr which mainly controls the gpr contrast parameter in the subsurface combining tdr data and lacquer peels from the quarry wall allowed the identification of various relationships between sediment characteristics and erlr synthetic radar traces constructed using the tdr logs and sedimentological data from the lacquer peels were compared with the actual gpr sections numerous peaks in erlr which are superimposed on a baseline value of 4 for dry sand are caused by potential gpr reflectors these increases in erlr coincide with the presence of either organic material having a higher water content and relative permittivity than the surrounding sediment or iron oxide bands enhancing relative magnetic permeability and causing water to stagnate on top of them sedimentary structures as reflected in textural change only result in possible gpr reflections when the volumetric water content exceeds 0ae055 the synthetic radar traces provide an improved insight into the behaviour of radar waves and show that gpr results may be ambiguous because of multiples and interference

the puzzle of the primary obsidian source in the region of paektusan china dpr korea abstract since the 1990s a characteristic obsidian geochemistry has linked widespread archaeological assemblages spanning the russian far east korean peninsula and northeast china referred to as pnk1 the source of this material has yet to be identified as a contribution to solving this enduring puzzle we report here analyses of a commercial specimen of obsidian exported from chongjin in dpr north korea a combination of neutron activation analysis naa and potassium argon dating enable us to compare this piece with a large obsidian database for northeast asia we find that the chongjin sample is identical to pnk1 lithics from archaeological collections while the exact source of the chongjin sample remains unknown we can more confidently locate the primary source for pnk1 lithics in dpr korea based on an exhaustive literature review of the geology and geochemistry of volcanic glasses and other volcanic rocks in the northern part of the korean peninsula and drawing on our own unpublished data we suggest that the pnk1 source is most likely located south of paektusan volcano this corroborates the existing evidence for the long range transport of the material

realising the potential of portable xrf for the geochemical classification of volcanic rock types abstract the ability to geologically classify stone artefact materials is crucial because it is the first step in provenance allocation and geochemical grouping that inform archaeological models used for understanding exchange systems within prehistoric social networks geochemical analyses have revolutionised exchange studies by making it possible to match stone artefacts back to quarry sources sometimes hundreds or thousands of kilometres away most archaeological basalt characterisation and provenance studies have relied on destructive sampling techniques to obtain the major trace elements nao2 k2o and sio2 wt to identify volcanic rock types on the total alkali silica tas diagram to overcome this limitation this paper presents an alternative method the pearce w f diagram that determines volcanic rock type and alkalinity using elements tio2 zr y and nb that are accurately detected by non destructive portable x ray fluorescence pxrf this new method is proven to be effective in a comparison with recent xrf archaeological basalt studies in the pacific the power to classify volcanic rock types non destructively with pxrf significantly increases the number of artefacts and museum objects available for inclusion in archaeological exchange studies

sediment transport and bedforms in a carbonate tidal inlet lee stocking island exumas bahamas an active oolitic sand wave was monitored for a period of 37 days in order to address the relationship between the direction and strength of tidal currents and the resultant geometry and amount and direction of migration of bedforms in carbonate sands the study area is situated in a tidal channel near lee stocking island exumas bahamas containing an estimated 5 5 to 6 105 m3 of mobile oolitic sand tidal ranges within the inlet are microtidal and the maximum current velocity at the studied site is 0 6 m s 1 at least 300 400 m3 of mostly oolitic sand are formed within or brought into the channel area every year the tidal inlet is subdivided into an ocean orientated segment in which sand waves are shaped by both flood and ebb tides and a platform orientated segment where sand waves are mainly shaped by flood tides the studied sand wave lies on the platformward flood tide dominated segment in a water depth of 3 5 4 5 m during the 37 days of observation the oolitic and bioclastic sand wave migrated 4 m in the direction of the dominant flood current the increments of migration were directly related to the strength of the tide during each tidal cycle bedforms formed depending on the strength of the tidal current tidal range and their location on the sand wave during flood tides a steep lee and a gentle stoss side formed and current ripples and small dunes developed on the crest of the sand wave while the trough developed only ripples the average lee slope of the sand wave is 24 2 and therefore steeper than typical siliciclastic sand waves during ebb tides portions of the crest are eroded creating a convex upward ebb stoss side covered with climbing cuspate and linguoid ripples and composite dunes the area between the ebb lee side and the trough is covered with fan systems sinuous ripples and dunes the migration of all bedforms deviated to a variable degree from the main current direction reflecting complex flow patterns in the tidal inlet small bedforms displayed the largest deviation migrating at an angle of up to 90 and more to the dominant current direction during spring tides

assessing the applicability of portable x ray fluorescence spectrometry for obsidian provenance research in the maya lowlands recent innovations in portable energy dispersive x ray fluorescence pxrf spectrometry have increased its utility for the geochemical characterization of obsidian artifacts for archaeological provenance research however concerns over the utility of pxrf instrumental analyses have been raised focused on the validity and reliability of the geochemical data produced here we adopt the framework of richard hughes on reliability validity and scale in obsidian sourcing research 1998 whereby reliability addresses instrument stability and issues of measurement while validity pertains to an instrument s ability to discern geochemical source provenance this is done in order to test the utility of pxrf instruments for archaeological provenance research k means cluster analysis was used to test the accuracy of pxrf through statistical comparison of data acquired via laboratory and portable energy dispersive xrf instruments multivariate analysis was employed to demonstrate obsidian source representation at two classic maya archaeological sites in southern belize uxbenka and ek xux and to test the validity of data obtained from a pxrf instrument in answering archaeological research questions pertaining to regional interactions between lowland maya polities results suggest that portable xrf instruments produce internally consistent results however data acquired from a pxrf instrument are not statistically equivalent to other xrf instruments this is to say that while pxrf is not a reliable technique it is valid for questions pertaining to geochemical source representation

establishing statistical confidence in cortex ratios within and among lithic assemblages a case study of the middle paleolithic of southwestern france abstract recent studies have demonstrated the usefulness of the cortex ratio for quantifying the cortex composition in lithic assemblages and as a viable index of prehistoric artifact transport yet the lack of means for assigning statistical confidence to archaeologically observed cortex ratios inhibits the approach s utility for objective comparisons and interpretation here we derive statistical confidence for archaeological cortex ratios through monte carlo and resampling techniques experimental data with known geometric properties and measured cortex values were employed as a reference for attaching a probability to an archaeological assemblage s cortex ratio the method is demonstrated on assemblages from the middle paleolithic sites of roc de marsal pech de l aze iv and combe capelle bas in southwestern france

integrating surface georadar and crosshole radar tomography a validation experiment in braided stream deposits we have used a combination of surface ground penetrating radar gpr profiling crosshole radar tomography and natural gamma ray logging to characterize a gravelly braided stream deposit in a gravel pit we conducted a survey using 300 mhz surface gpr 250 mhz crosshole radar and densely sampled gamma ray logging at single borehole locations after excavation we validated the geophysical results by comparison with the sedimentological and hydrogeological information obtained from the corresponding outcrop wall we found the visual lithofacies boundaries agreed very well with the images provided by applied geophysical techniques our results illustrate how gpr reflector images are improved using tomographic velocity information in addition the structural interpretation of tomographic velocity fields is guided by the gpr reflector images in combination with natural gamma ray logging results groundwater flow and transport modeling was also performed on different subsurface models the hydrogeological r

cenozoic episodic volcanism and continental rifting in northeast china and possible link to japan sea development as revealed from k ar geochronology abstract cenozoic volcanic rocks in northeast china comprise part of the volcanic belt of the western circum pacific rim and represent one of the presently active tectono magmatic regions of the world over 590 volcanoes with erupted basalts covering an area of 50 000 km 2 are exposed in the songliao graben and particularly on its flanks k ar dating of the volcanic rocks sampled from a selection of eruption sites over the region reveals that the volcanism occurred episodically through the entire cenozoic corresponding to the tectono magmatic interactions particularly between the india eurasia and pacific plates the volcanism initiated in the songliao graben in late cretaceous 86 ma and migrated flankward since 28 ma the magmatic propagation shows three major stages intimately associated with the evolution of japan sea and related to the geodynamic forcing of the india eurasia collision prior to japan sea rifting volcanic eruptions were restricted to the songliao basin during japan sea opening volcanism migrated into the lateral belts after cessation of japan sea opening at 15 ma volcanism with greatest intensity occurred on both flanks particularly along the yi yi fault system around 14 13 ma and subsequently the fu mi fault between 11 and 7 ma continuing this trend of migration eruptions scattered further away from the songliao basin in the last 4 5 ma we suggest that the cenozoic volcanic belt in northeast china and the japan sea backarc basin are competitive parts in the eastern marginal magmatic system of the eurasian plate the early stage of the volcanism in the songliao basin may have resulted from mantle upwelling beneath the songliao bohai basin belt rifting of the ne faults and relatively weak intensity of volcanism in northeast china during japan sea opening could be attributable to the lithospheric breakup in the japan sea and spreading of japan sea the subsequent strong volcanism in northeast china after cessation of the japan sea opening implicates the easiest pathway for the melts of the magmatic system in the plate margin the diversified volcanism in scattered localities during the quaternary may indicate localized melting processes or notable modifications in smaller sized individual domains and possibly a magmatically waning phase of the limited source in eastern china

three dimensional ground penetrating radar imaging of sedimentary structures fractures and archaeological features at submeter resolution contemporary geoscientific shallow subsurface assessment chiefly relies on outcrops drilling excavations and sometimes geophysics often the information gathered is insufficient to accurately characterize the archaeological and or geologic record and ongoing shallow subsurface processes that affect a variety of economic and environmental aspects of our society the extra effort of acquiring very dense ground penetrating radar gpr survey grids and three dimensional 3d data processing transforms uncorrelatable and uninterpretable gpr signals into clear images of complex shallow subsurface anatomy with an unprecedented resolution here we present two examples of noninvasive 3d shallow subsurface imaging example 1 images decimeter to meter scale sedimentary structures in a pleistocene oolite shoal barrier bar setting example 2 images the fracture network in a triassic limestone quarry denser than quarter wavelength grid acquisition in combination with 3d migration processing focuses scattered energy and removes out of plane reflections in addition to conventional vertical cross sections horizontal depth slices and data volume animations reveal previously unseen diagnostic patterns of past human activities laterally changing depositional processes and fracture networks including near vertical joints with millimeter apertures

validity of off the shelf handheld portable xrf for sourcing near eastern obsidian chip debris handheld portable xrf hhpxrf has received considerable recent attention in archaeology especially for obsidian sourcing published studies largely suggest a high potential for success hhpxrf though has been met with debate and scepticism concerns fall into three categories 1 low accuracy and precision 2 data correction schemes and calibration and 3 ignorance of fundamental xrf issues such as specimen size limits and morphology effects the result is that archaeological interpretations in hhpxrf based studies are cast into doubt should interpretations be believed if authors did not follow the perceived best practices to address such questions the validity of hhpxrf for near eastern obsidian sourcing was tested under deliberately sub optimal conditions irregular obsidian debitage near the minimum size limits was sourced with a success rate of 94 based on a rank matches to 100 based on a and b rank matches even under conditions chosen to mimic off the shelf operation

ground penetrating radar for high resolution mapping of soil and rock stratigraphy ground penetrating radar is a technique which offers a new way of viewing shallow soil and rock conditions the need to better understanding overburden conditions for activities such as geochemical sampling geotechnical investigations and placer exploration as well as the factors controlling groundwater flow has generated an increasing demand for techniques which can image the subsurface with higher resolution than previously possible the areas of application for ground penetrating radar are diverse the method has been used successfully to map ice thickness water depth in lakes bedrock depth soil stratigraphy and water table depth it is also used to delineate rock fabric detect voids and identify karst features the effective application of the radar for the high resolution definition of soil stratigraphy and fractures in bedrock is highlighted the basic principles and practices involved in acquiring high quality radar data in the field are illustrated by selected case histories one example demonstrates how radar has been used to map the bedrock and delineate soil horizons to a depth of more than 20 m two case histories show how radar has been used to map fractures and changes of rock type to 40 m range from inside a mine another case history demonstrates how radar has also been used to detect and map the extent of groundwater contamination the corroboration of the radar results by borehole investigations demonstrates the power and utility of the high resolution radar method as an aid for interpolation and extrapolation of the information obtained with conventional coring programmes with the advent of new instrumentation and field procedures the routine application of the radar method is becoming economically viable and the method will see expanded use in the future

initial source evaluation of archaeological obsidian from the kuril islands of the russian far east using portable xrf obsidian artifacts recently have been recovered from 18 archaeological sites on eight islands across the kuril island archipelago in the north pacific ocean suggesting a wide ranging distribution of obsidian throughout the island chain over the last 2 500 years although there are no geologic sources of obsidian in the kurils that are known to have been used prehistorically sources exist in hokkaido japan and kamchatka russia the southern and northern geographic regions respectively from which obsidian may have entered the kuril islands this paper reports on the initial sourcing attempt of kuril islands obsidian through the analysis of 131 obsidian artifacts data from this research were generated through the application of portable xrf technology and are used to address research questions concerning prehis toric mobility exchange and social networking in the kuril islands

on the provenance of prehistoric obsidian artifacts in south korea abstract using a series of geochemical data from obsidian samples taken from unmodified rocks and prehistoric sites we investigated the provenance of some obsidian artifacts found in south korea by using la icp ms and shrimp methods we analyzed rare earth elements rees and lead pb isotopic ratios of obsidian samples from the north korean side of the baekdusan mountain nk and artifacts from a neolithic site in gadeokdo southeast coast of south korea bg published accounts on the elemental correlation of previously analyzed samples were re examined in consideration of their geological compatibility it appears that the prehistoric artifacts from the middle to northern part of south korea have a genetic relationship with obsidians from the baekdusan area whereas those of the southern part are related to kyushu japan ree patterns of the bg and the nk samples demonstrate a prominent contrast between them suggesting their different provenances presumably the bg obsidians are related to the volcanic rocks of kyushu given that pb isotopic ratios are indicative of the relative contribution of crust versus mantle component to the volcanic magma they indicate the addition of a crustal component to the volcanic magma for the baekdusan volcanic rocks and the nk obsidians the kyushu volcanics and the bg obsidians have a relative affinity to the mantle component the geochemical approach adopted in the current research may be regarded as an accurate and effective means to discriminate and isolate obsidian sources helpful for provenance and other archaeological study of obsidian artifacts

medieval phases of settlement at benabbio castle apennine mountains italy evidence from ground penetrating radar survey the lack of written sources for many of the medieval castles in the northern apennines italy makes it difficult to completely establish the most ancient historical phases of these settlements the church of san michele belongs to an abandoned fortified settlement of the castle of benabbio in the mountains surrounding lucca thanks to an epigraph still visible on the facade the church foundation is dated back to ad 1218 however several archaeological findings at the settlement seem to suggest stages of encastlement that are older than the church foundation a ground penetrating radar gpr survey has been carried out in the inner part of the church in order to identify the presence of pre ad 1218 buried structures a 0 5 m grid was used to acquire gpr data over the entire pavement of the church using an antenna of 200 mhz of nominal peak frequency a standard sequence of raw data processing was adopted and the interpretation was performed both on vertical radar profiles and time slices the distribution of areas of high back scattered electromagnetic energy shows regular patterns with orthogonal alignments archaeologically compatible with buried stone walls in the western sector of the church the subsurface structures are consistent with the wall remains of a building which due to its size and shape is unlikely to have been used for religious activities this building can be related to an 11the12th century encastlement of the site the other structures detected by gpr prospection can be referred to the construction of the 13th century romanesque church while its renaissance enlargement may have taken place in the late 15th century during this last phase a hypogean room was excavated near the altar and probably used as crypt ossuary the results of this multidisciplinary work have supported some archaeological hypotheses concerning the architectural history of the church dating back to the 11the12th century when the first stone structures of the benabbio castle were erected

timescale and evolution of the intracontinental tianchi volcanic shield and ignimbrite forming eruption changbaishan northeast china abstract around the tianchi eruption cone the junjianshan formation which builds the tianchi basalt shield can be divided into three units they are from bottom to top the toudao baishan and laofangzixiaoshan units respectively individual basaltic flows of the tianchi shield vary significantly in volume and in spatial distribution from a few to dozens of kilometers in length hundreds to thousands of meters in width and a few to dozens of meters in thickness k ar age data indicate that the tianchi shield was formed within a very short time period between 2 77 0 08 and 0 31 0 002 ma our detailed mapping in combination with the k ar dating shows that the toudao unit erupted at 2 77 1 99 ma the baishan unit at 1 64 1 11 ma and the laofangzixiaoshan at 0 31 0 58 ma the huge millennium eruption from the tianchi volcano sustained a 35 km high column h t and lasted a few days producing the comenditic ignimbrite around the volcano wiggle matching measurements of a sample series of charcoal wood indicate the millennium eruption might have happened around 1024 ad features of eruptions stemming from the same source surrounding the tianchi volcano plus the volcanic evolution from effusive flows to explosive eruption are interpreted to reflect crustal thickening within this intracontinental tectonic environment field observations and lava compositional variations suggest that crystal fractionation and magma mixing or mingling process must have played an important role in the development and evolution of the tianchi volcano