nature of laminations and mineralization in rhinoceros enamel using histology and x ray synchrotron microtomography potential implications for palaeoenvironmental isotopic studies abstract incremental features of rhinoceros molar enamel were studied quantitatively on histological slices the different kinds of incremental features of enamel were related to one another and counted to determine the rate and duration of crown formation and to clarify the status of the laminations the mineralization and the microstructure of the enamel were examined in a rhinoceros molar germ using x ray synchrotron microtomography respectively using absorption and phase contrast mode at different levels of resolution from 45 71 m for the largest scale up to 0 28 m for the finest one the different microtomographic data were combined to obtain a multiscale integrated overview of the microstructure and mineralization in order to understand better the relationship between these two aspects additional human and herbivorous mammal teeth were examined qualitatively using histological sectioning to obtain a better understanding of laminations in mammal tooth enamel laminations regularly spaced features parallel to the retzius lines represent regular isochrons of enamel deposition this study shows that laminations and cross striations are equivalent daily features in enamel of rhinoceros humans and probably of middle sized and large herbivorous mammals in general laminations are shown to be three dimensional alignments of cross striations in addition to the fact that cross striations are visible only in prismatic enamel observation of histological slices and high resolution phase contrast x ray synchrotron microtomography demonstrate three main parameters influencing the dominant aspect of daily features in rhinoceros and human enamel the angle between prisms and retzius lines the enamel deposition rate and the thickness of the histological slices given their daily nature laminations can be used to determine the crown formation time of middle sized and big herbivorous mammals quantitative study of the enamel mineralization in the rhinoceros germ fragment using x ray synchrotron microtomography suggests that the innermost 20 m of the enamel near the enamel dentin junction are highly mineralised 77 90 of the final enamel mineralization during or just after the deposition of the corresponding enamel matrix integrated microtomographic study shows that this area corresponds to the thin aprismatic enamel layer at the edj level plus a thin layer of radial enamel directly adjacent it appears that in some parts of the enamel there may be a considerable time lag between matrix deposition and full maturation which could have important implications for geochemical studies this study reinforces the previously suggested hypothesis that isotopic measurements derived from the innermost enamel may represent the period most closely related to matrix secretion by using information derived from incremental features laminations and retzius lines and restricting the isotopic measurements to the innermost part of the enamel precise temporal calibration of isotopic signals should be possible and the complication of time averaging due to enamel maturation could be avoided or strongly reduced

pure shear and simple shear calcite textures comparison of experimental theoretical and natural data abstract the pattern of lattice preferred orientation texture in deformed rocks is an expression of the strain path and the acting deformation mechanisms a first indication about the strain path is given by the symmetry of pole figures coaxial deformation produces orthorhombic pole figures while non coaxial deformation yields monoclinic or triclinic pole figures more quantitative information about the strain history can be obtained by comparing natural textures with experimental ones and with theoretical models for this comparison a representation in the sensitive three dimensional orientation distribution space is extremely important and efforts are made to explain this concept we have been investigating differences between pure shear and simple shear deformation incarbonate rocks and have found considerable agreement between textures produced in plane strain experiments and predictions based on the taylor model we were able to simulate the observed changes with strain history coaxial vs non coaxial and the profound texture transition which occurs with increasing temperature two natural calcite textures were then selected which we interpreted by comparing them with the experimental and theoretical results a marble from the santa rosa mylonite zone in southern california displays orthorhombic pole figures with patterns consistent with low temperature deformation in pure shear a limestone from the tanque verde detachment fault in arizona has a monoclinic fabric from which we can interpret that 60 of the deformation occurred by simple shear

rheology of synthetic polycrystalline halite in torsion abstract motivated by the need for halite rheology we investigated the stress strain strain rate behaviour of halite to high shear strains in torsion using polymer jackets whose strength does not influence halite rheology the experimental results show that 1 halite strength decays exponentially with temperature increase being very weak at 300 c ca 2 nm 2 power laws fit the stress strain rate data from which we determined the stress exponent n between ca 13 60 c and ca 3 200 c indicating that n decreases exponentially with temperature increase 3 the activation energy q decreases exponentially with temperature increase from ca 159 kj mol 38 kcal mol at 60 c to ca 59 kj mol 14 kcal mol at 200 c 4 q depends linearly on n with a slope of ca 10 the empirical constitutive equation 12 1 exp 9 6 7 1 e 6 exp 1 t 1 9 e 4 2 5 9 3 e6exp t 24 3 describes the experimental results comparison of the present and previous experimental results shows that halite is much weaker in shear than in axial compression or extension this difference likely results from the rotational component of simple shear

the middle pleistocene archaeological record of greece and the role of the aegean in hominin dispersals new data and interpretations abstract in the debate about hominin dispersals greece is expected to have been among the core areas for the peopling of eurasia serving as a refugium and source region for re colonizations yet its early pleistocene record is still scarce forming a conspicuous gap in the early human geography of the mediterranean here we investigate this gap and provide for the first time a synthesis of the lower palaeolithic record of greece our study adopts a geoarchaeological approach to explain the current status of the record and argues that the absence of evidence should be understood as the result of the biasing effects of erosional geomorphic processes and not as an indication of a former absence of hominins in this line the potential for archaeological preservation and recovery is assessed as a function of landscape dynamics climatic seasonality tectonic activity high relief and marine inundations have altogether contributed to significant reworking and or total loss of archaeological sites in spatial terms only about 2 5 of the lower palaeolithic record of greece may have survived up to the present on the other hand we interpret recent geological data which show that half of the aegean sea would have been subaerially exposed for most of the early pleistocene our results emphasize the potentially central role of the aegean region in hominin dispersals both as a biogeographical landbridge and as a highly productive landscape for occupation this conclusion opens up new prospects for future fieldwork in an area that was hitherto essentially neglected finally in showing how geomorphic processes bias site distribution patterns the results and methodological perspective developed here can be seen as having implications that are wider than the geographical limits of the greek peninsula they are pertinent to the investigation and interpretation of the early pleistocene archaeological records in the highly dynamic landscapes of southern europe if not in even broader scales

mobility of middle holocene foragers in the cis baikal region siberia individual life history approach strontium ratios rare earth and trace elements abstract previous geochemical work conducted on the materials from the khuzhir nuge xiv cemetery on lake baikal siberia has demonstrated the effectiveness of using 87 sr 86 sr ratio analysis in interpreting mobility patterns among early bronze age hunter gatherer groups the research reported here focuses on six small cemeteries representing the little sea and upper lena micro regions as well the early neolithic en ca 8000 7200 cal bp and early bronze age eba ca 5200 3400 cal bp periods thus expanding both the geographic and chronological scope of the previous work the reference collection of environmental samples to document bioavailability of the measured geochemical tracers was also expanded substantially by inclusion of samples of modern plants and water from lake baikal and a number of surrounding rivers first second and third molars of 14 adult individuals were tested for 87 sr 86 sr ratios as well as rare earth and trace element concentrations using la icp ms each human tooth was micro sampled at four locations along the crown enamel thus providing data of higher temporal resolution relative to a single sampling locus geochemical signatures for water plant and animal bone samples were found to be far more variable across the region than predicted based on the age and type of geologic formations 87 sr 86 sr ratios for cultural micro regions proved to overlap significantly and required trace element data to identify more discrete geochemical groups the level of hunter gatherer mobility between and within the analyzed micro regions was found to be significant with individuals recovered from the upper lena showing contact with the little sea micro region along the northwest coast of the lake

strontium isotope evidence of neanderthal mobility at the site of lakonis greece using laser ablation pimms we report here direct evidence for neanderthal mobility through the measurement of strontium isotope ratios in tooth enamel using laser ablation which allows us to use much smaller samples than traditional methods there has been a long standing debate over the extent of neanderthal mobility with some arguing for neanderthals having a very limited geographic range and others for more substantial and even seasonal lifetime movements we sampled across the enamel of a neanderthal third molar from the site of lakonis greece dating to ca 40 000 years ago the tooth was found in a coastal limestone cave yet the strontium isotope values indicate the enamel was formed while the individual resided in a region with bedrock consisting of older more radiogenic volcanic bedrock therefore this individual must have lived in a different more radiogenic location during this period of third molar crown formation likely to be between the ages of 7 and 9 years than where the tooth was found this strontium isotope evidence therefore indicates that this neanderthal moved over a relatively wide i e at least 20 km geographical range in their lifetime

the karst site of las palomas guadalteba county malaga spain a preliminary study of its middle late pleistocene archaeopaleontological record abstract cleaning works in the cave of las palomas in teba malaga spain developed by the guadalteba consortium have provided a number of lithic tools and knapping products that may be ascribed to the mode iii technotypological tradition as well as remains of a number of large mammal species typical of middle late pleistocene times topographic measurements help to place this ancient cave within a karst landform this discovery opens up new perspectives in the research on the neanderthal groups that inhabited the valleys of guadalteba and turon rivers in the middle basin of the guadalhorce river and thus in the southern region of the iberian peninsula

simple shear experiments on calcite rocks rheology and microfabric ideal simple shearing of carrara marble and solnhofen limestone was achieved by inserting calcite rock slices into sandstone cylinders precut at 35 the experiments covered a wide range in temperatures 25 900 c at confining pressures of 200 and 250 mpa and at strain rates between 10 3 and 10 5 s 1 shear strains of up 2 7 were achieved the stress strain data for simple shear favourably compare with predictions on the basis of existing flow laws established in coaxial testing this comparison demonstrates that the simple shear experiments covered most of the previously established flow regimes for calcite rocks at the highest temperatures carrara marble exhibited substantial work softening after high shear strains a complete texture analysis was carried out with the u stage and a texture goniometer the following four distinct microfabric regimes were found 1 twinning regime an oblique c axis maximum deflected from the pole to the flattening plane towards 1 and against the imposed sense of shear results directly from e twinning extensive twinning some grains are completely twinned rapidly rotates the c axes into near parallelism with 1 this regime was observed for carrara marble deformed at temperatures below 700 c and for solnhofen limestone at room temperature 2 intracrystalline slip regime three c axis maxima were observed in both rock types at more elevated temperatures and in the absence of twinning these c axis orientations result from an alignment of slip planes and slip directions into parallelism with the shear zone boundary and the shear direction respectively this finding supports the idea of an orientation for easy slip resulting from simple shearing in addition to r and f glide basal glide is inferred to have been operative 3 grain boundary sliding regime a great circle distribution of c axes approximately perpendicular to the direction of finite shortening is observed this texture is weaker compared to the other regimes it is interpreted to result from minor contributions of f slip towards total strain this regime is restricted to fine grained solnhofen limestone deformed at the highest temperatures 4 grain boundary migration regime only in carrara marble deformed at the highest temperatures is there substantial grain boundary migration recrystallization the texture consists of a dominant c axis maximum oriented perpendicular to the shear zone boundary this single maximum corresponds to an orientation for easy slip for basal slip grain boundary migration assists rapid lattice reorientation and leads to geometrical work softening quantitative analysis of grain boundary surface orientations gave the following results within the twinning and the intracrystalline slip regimes the characteristic grain shape is elliptical for both rock types the strain ellipses derived from this analysis closely correspond to the known finite strain at the lowest temperatures at intermediate temperatures and especially in carrara marble there is a consistent trend for the aspect ratios to indicate too little flattening and for the angles between the long axis of the strain ellipse and the shear zone boundary to be too small in the absence of grain boundary migration recrystallization this finding indicates minor translations of grains with respect to one another grain boundary sliding or translations accommodated in the mantle regions of grains at the highest temperatures where extensive grain boundary migration occurs in carrara marble grain boundary migration regime two preferred orientations of grain boundaries are observed 1 parallel to the shear zone boundary and 2 parallel to an oblique direction deflected 20 away from the normal to the shear zone boundary in the sense of the imposed shear the same pattern of grain boundary alignment is observed in solnhofen limestone deformed in the grain boundary sliding regime the geological applications of this experimental work are discussed in terms of calcite tectonites in particular and sheared rocks in general

experimental shear zones and magnetic fabrics abstract magnetic fabric analysis has been used as a non destructive means of detecting petrofabric development during experimentally produced multi stage transpressive deformations in shear zones artificial magnetic bearing silicate sands and calcite sands bonded with portland cement were deformed at room temperature and at 100 and 150 mpa confining pressure the slip rate for the shear zone walls was 0 73 10 4 mm s 1 and the maximum shear strains were about 0 38 across zones that were initially about 5 mm thick the magnetic fabric ellipsoid rapidly spins so that the maximum and intermediate susceptibilities tend to become parallel to the shear zone walls throughout the sheared zone the ellipsoid becomes increasingly oblate with progressive deformation however in all cases the anisotropy is strongly influenced by the pre deformation magnetic fabric during deformation the cement gel collapses so that cataclasis of the mineral grains is suppressed in the quartz feldspar aggregates the magnetite s alignment is accommodated by particulate flow intergranular displacements of the grains in the calcite aggregates stronger magnetic fabrics develop due to plastic deformation of calcite grains as well as particulate flow however the calcite grain fabrics are somewhat linear l s whereas the magnetic fabrics are planar s l the preferred dimensional orientations of magnetite are weak and it is possible that the magnetic fabrics are due to intragranular rearrangements of magnetic domains the transpressive shear zones are much more efficient than axial symmetric shortening in the increase of anisotropy of the magnetic fabrics especially in the case of the calcite aggregates this suggests that flow laws derived for axial symmetric shortening experiments may not be appropriate for non coaxial strain histories such as those of shear zones

fabric development in mg fe o during large strain shear deformation implications for seismic anisotropy in earth s lower mantle abstract large strain shear deformation experiments were performed on mg 1 x fe x o x 0 25 1 0 one of the important minerals in earth s lower mantle deformation experiments were made on coarse grained 15 20 m grain size hot pressed aggregates at conditions of t t m 0 46 0 65 t temperature t m melting temperature and 0 4 10 3 to 0 9 10 3 differential stress shear modulus up to the shear strain of 7 8 under these conditions deformation occurs by dislocation creep the microstructural development in mg fe o is found to be sluggish and the complete dynamic recrystallization and nearly steady state fabric lattice preferred orientation are achieved only after shear strains of 4 at nearly steady state mg fe o shows strong fabrics characterized by the 1 1 0 axes being parallel to the shear direction and the poles of the 1 0 0 planes and to a lesser extent the poles of the 1 1 1 planes normal to the shear plane the seismic anisotropy corresponding to the deformation fabrics in mg fe o was calculated the nature of anisotropy corresponding to a given flow geometry changes significantly with strain as a result of fabric evolution anisotropy changes also with depth pressure due to the large variation of elastic anisotropy of mg fe o with depth seismic anisotropy caused by the deformation fabric of mg fe o is very weak in the shallow lower mantle v sh v sv anisotropy assuming that mg fe o occupies 20 volume fraction of the lower mantle and little shear wave splitting of vertically travelling waves a result that is consistent with the seismological observations in the d layer of the circum pacific regions thus the deformation fabric of mg fe o is a vital candidate of the cause of seismic anisotropy in these regions anisotropy caused by the lattice preferred orientation of mg fe o has a distinct azimuthal anisotropy with a strong 4 term azimuth the direction of propagation of the fastest slowest sh or p wave is parallel perpendicular to the flow direction and the slowest fastest sh or p wave is at 45 from these two directions

origin of kinkbands and shear band cleavage in shear zones an experimental study specimens of artificial kcl mica schist have been deformed in simple shear with different initial orientations 10 intervals between 0 and 170 of the mica schistosity s1 relative to the imposed simple shear plane for most experiments the angular shear strain was 30 the strain rate 4 8 10 4s 1 and the stress normal to the imposed shear plane 20 mpa all experiments were conducted at room temperature deformation of the specimens is achieved largely by slip parallel to the s1 mica foliation however two new types of slip surfaces also develop as either a single orientation set or as a pair of conjugate sets these new slip surfaces are kinkbands and a shear band cleavage the type and number of sets of new slip surfaces which develop depends on the orientation of s1 relative to the shortening and extension fields of the instantaneous strain ellipsoid our experiments indicate that kinkbands or shear band cleavage form in shear zones in which s1 is inclined to the margin of the zone which structure forms and whether it occurs as a single set of structures or as a conjugate pair depends on the initial orientation of s1 in situations where s1 is parallel to the margins of the zone neither structure develops if the deformation is a simple shear the presence of kinkbands or shear band cleavage in such zones where s1 is parallel to the margins is an indication that the zones were transtensional or transpressional respectively we conclude that shear band cleavage is not only an excellent indicator of shear sense but also a qualitative indicator of the ratio of s1 normal shortening to s1 parallel shear conjugate shear bands indicate that s1 normal shortening was relatively strong and single shear band sets indicate that s1 parallel shear was relatively strong

zagros phantom earthquakes reassessed the interplay of seismicity and deep salt flow in the simply folded belt unraveling the contributions of main shock slip aftershocks aseismic afterslip and postseismic relaxation to the deformation observed in earthquake sequences heightens our understanding of crustal rheology triggering phenomena and seismic hazard here we revisit two recent earthquakes in the zagros mountains iran which exhibited unusual and contentious aftereffects the mw 6 earthquakes at qeshm 2005 and fin 2006 are both associated with large interferometric synthetic aperture radar insar signals consistent with slip on steep reverse faults in carbonate rocks of the middle sedimentary cover but small aftershocks detected with local seismic networks were concentrated at significantly greater depths this discrepancy can be interpreted in one of two ways either 1 there is a genuine vertical separation between main shock and aftershocks reflecting a complex stress state near the basement cover interface or 2 the aftershocks delimit the main shock slip and the insar signals were caused by shallow updip afterslip phantom earthquakes with very similar magnitudes mechanisms and geographical positions as the original earthquakes here we show that main shock centroid depths obtained from body waveform modeling which in this instance is the only method that can reveal for certain the depth at which seismic slip was centered strongly support the first interpretation at qeshm microseismic aftershock depths are centered at the level of the hormuz formation an infracambrian sequence of intercalated evaporitic and nonevaporitic sediments these aftershocks may reflect the breaking up of harder hormuz sediments and adjacent strata as the salt flows in response to main shock strain at the base of the cover this work bolsters recent suggestions that most large earthquakes in the zagros are contained within carbonate rocks in the midlower sedimentary cover and that the crystalline basement shortens mostly aseismically

tracing population mobility in the aegean using isotope geochemistry a first map of local biologically available 87sr 86sr signatures abstract strontium isotope ratio 87sr 86sr analysis of archaeological human skeletal remains is an efficient method of investigating past population movement and residential mobility by determining probable geographical origins for the individuals examined for this to be achieved however a map of biologically available 87sr 86sr signatures across the region investigated is needed this paper presents a first such map for the aegean based on 87sr 86sr values recovered mainly from archaeological animal dental enamel and modern snail shells from sites largely distributed in the southern part of this region although not exhaustive this comprehensive dataset of local biologically available 87sr 86sr signatures shows a marked difference between mainland sites of the pindos and parnassos zones and the islands of south eastern aegean crossed by the sub pelagonian zone 0 70808 0 70869 and sites in the central cyclades and the north eastern aegean islands falling into the attic cycladic metamorphic belt and the vardar zone respectively 0 70926 0 71187 biologically available 87sr 86sr values from sites on central euboea in the pelagonian zone south eastern attica and the western cyclades in the attic cycladic metamorphic belt and on crete in the gavrovo zone are also relatively high 0 70853 0 70931 but lower than those recorded for the central cyclades and the north eastern aegean

comments on richards et al journal of archaeological science 35 2008 strontium isotope evidence of neanderthal mobility at the site of lakonis greece using laser ablation pimms we present an evaluation of the laser ablation sr isotope data reported by richards et al 2008 for a neanderthal tooth recovered from a site in greece based on an alternative and analytically more robust method of correcting for isobaric interferences present during the analysis the tooth appears to be isotopically homogenous and within uncertainty of the value for modern seawater if this is the case then contrary to the migration model proposed by richards et al 2008 the neanderthal individual may have actually been a coastal dweller and lived within the vicinity of the find site

the first large scale bioavailable sr isotope map of china and its implication for provenance studies abstract strontium isotope ratio 87sr 86sr has been widely used to trace human migrations across geologically distinct landscapes in archaeological and forensic sciences 87sr 86sr based provenance studies require a detailed strontium reference map to make valid interpretations of mobility patterns for a given region in this study we first review the previous development for 87sr 86sr isoscapes relevant to research on migration and then present the first map of bioavailable 87sr 86sr ratios for china based on 1935 measurements on biosphere samples collated from published research and supplemented by our targeted collection strategy the results show that 87sr 86sr ratios in china span a large range and exhibit regional patterns largely dependent on the divergent geological conditions of each of china s tectonic blocks we further combine river water 87sr 86sr ratios with lithology integrated elemental data and chemical weathering rates to determine which dominant weathering patterns e g silicate carbonate or evaporite have the most significant influence on 87sr 86sr ratios the low ranges of 87sr 86sr ratios 0 7125 appear in the cathaysia block as well as some orogenic belts and the southeastern margin of the tibetan plateau likely due to the influence of the metamorphic rocks and granitoid sources additionally topography differential weathering among lithologies and eolian deposits e g loess are also significant factors that influence 87sr 86sr ratios in china our study reveals that the large variation of 87sr 86sr ratios across china is predominately driven by geological conditions revealing that future sr isotope provenance studies can shed on ancient and historical migrations in china

strontium isotope analysis of curved tooth enamel surfaces by laser ablation multi collector icp ms abstract laser ablation multi collector icp ms la mc icp ms is increasingly applied to measure the strontium isotope composition 87 sr 86 sr of fossil or modern tooth samples in order to address questions about mobility recently concerns have been raised that an analytical bias due to instrumental isotopic mass fractionation might be introduced when this method is used to sample across naturally curved tooth enamel surfaces we address this concern by reanalyzing data that were originally produced using 750 m linear la mc icp ms scans on the external slightly curved surfaces of fossil hominin teeth australopithecus and paranthropus from south africa by re integrating the first and last 1 3 of the data along the original 750 m linear scans we compared 87 sr 86 sr results produced by sections of each scan with varying degrees of laser focus the results show no evidence of any analytical scatter between strontium isotope values for the different sections of the curved tooth surfaces and results for the different sections of each linear scan agree well within the precision of the method external 2 0 0004 furthermore each analytical session was bracketed by analysis of a curved rodent otomys sp tooth in house standard with up to 100 m vertical change along the 750 m linear scan long term average la mc icp ms 87 sr 86 sr results for one such otomys tooth standard 0 72989 0 00029 n 71 agree well with the solution mc icp ms analysis of the same tooth 0 72976 0 00002 new la mc icp ms 87 sr 86 sr ratios using both a 213 nm and solid state 193 nm laser ablation system for sets of consecutive 750 m linear scans along the curved outer tooth enamel surface on another single otomys tooth in house standard agree within 0 0004 regardless of progressively more extreme vertical change during analysis 10 m to 900 m these results are similar to la mc icp ms sr isotope analyses using the same instrumentation and methodology of an in house polished flat clinopyroxene mineral standard la 0 70482 0 00029 n 155 solution 0 70495 0 00003 we conclude that provided the stable 86 sr 88 sr ratio is used in conjunction with the exponential law to constantly correct for instrumental isotopic mass fractionation during acquisition curved tooth enamel surfaces represent no impediment to accurate la mc icp ms strontium isotope analyses

assessing life history from commingled assemblages the biogeochemistry of inter tooth variability in bronze age arabia abstract stable isotopes represent a remarkable means of assessing the life histories of individuals in the archaeological record primarily by taking advantage of multiple skeletal tissues that form and remodel throughout life however this methodological tool also has the potential to provide crucial information on the life histories of individuals represented only by commingled fragmentary and otherwise isolated human skeletal remains particularly when more traditional methods of evaluation are not possible in this study a sequential analysis of radiogenic strontium 87sr 86sr and stable oxygen 18o isotopes of associated molars from the in situ mandibular or maxillary fragments of 19 commingled individuals from multiple bronze age tombs in the united arab emirates was undertaken in order to examine temporal changes in mobility at the level of the individual the majority of individuals display little difference in inter tooth isotope ratios suggesting a general lack of residential mobility between early childhood and late adolescence an unexpected result given abundant evidence artifactual and written for a population actively engaged in both regional and interregional trade in the third millennium bc however two individuals from the emirate of fujairah demonstrate disparate inter tooth 87sr 86sr values likely indicative of some migration event which calls into question the supposed cultural isolation of the region during the second millennium bc

comments on coltrain et al journal of archaeological science 31 2004 sealing whaling and caribou the skeletal isotope chemistry of eastern arctic foragers and coltrain journal of archaeological science 36 2009 sealing whaling and caribou revisited additional insights from the skeletal isotope chemistry of eastern arctic foragers abstract in recent papers coltrain et al sealing whaling and caribou the skeletal isotope chemistry of eastern arctic foragers journal of archaeological science 31 39 57 and coltrain sealing whaling and caribou revisited additional insights from the skeletal isotope chemistry of eastern arctic foragers journal of archaeological science 36 764 775 propose that four previously excavated human skeletons from native point southampton island nunavut canada are dorset paleoeskimo and european the suggested reclassification of one burial as dorset is based upon a single radiocarbon assay and interpretation of isotopic values the authors conclusion that three other individuals found together inside an aboriginal dwelling were european rests on an isotopic signature indicative of a terrestrial diet as well as radiocarbon date ranges this paper assesses the information used by coltrain et al 2004 and coltrain 2009 to reach these conclusions and in contrast to those authors determines that the data is equivocal at best and does not support revision of the individuals biocultural affinity the paper stresses the necessarily critical role that must be given to archaeological context in any interpretation or reinterpretation of human remains

experimental deformation of a single layer anhydrite in halite matrix under bulk constriction part 1 geometric and kinematic aspects a new deformation apparatus has been used to model the internal kinematics of salt diapirs composite natural samples consisting of a single layer of anhydrite embedded in halite matrix were constrictionally deformed at temperature t 345 c strain rate 10 7 s 1 maximum viscosity 2 1013 pa s and maximum finite strain ex 122 the anhydrite layer oriented parallel to the major stretching axis x was deformed by fracturing whereas halite behaved viscously at advanced state of constriction ex 90 a strong increase in strain hardening of halite led to a transient tension fracture that healed up and was shortened by folding during the final phase of viscous deformation tiny prismatic anhydrite inclusions disseminated inside the halite matrix were reoriented during constriction resulting in a linear grain shape fabric 3d images of the anhydrite layer based on computer tomography revealed rare kink folds with axes subparallel to x and boudins which result from tension fracture with increasing layer thickness hi the width of boudins wa increases linearly wa 0 3 1 3 hi the normalized width of boudins wd wa hi is almost constant at 1 5 1 0 these geometrical parameters can be used to reveal fracture boudinage under bulk constriction the oblique orientation of most of the boudins with respect to the principal strain axes results from folding of the boudins by a second generation of folds the latter with axes subperpendicular to the layer

occupation dynamics north of the carpathians and sudetes during the weichselian mis5d 3 the lower silesia sw poland case study abstract this study provides new data about the chronological framework as well as revising the occupational model of the neanderthals in areas north of the carpathians and sudetes during mis 5 and mis 3 according to the current numerical dating from key sites in central europe the settlement hiatus between mis 5a and the time of occurrence of transitional industries 45 40 ka postulated in earlier publications should be dismissed with the exception of mis 4 74 59 ka neanderthals exploited this area before the appearance of transitional industries the estimation of mean annual temperatures mat based on the stable oxygen isotope composition of animal bones enabled understanding of climatic as well as the environmental factors governing this process neanderthals were especially active in this part of central europe during the warmer events of the weichselian they mainly inhabited scattered patches rich in food sources and used diverse strategies of blank and tool production formal and expedient ones analysis of technological and functional parameters of flint artefacts showed that similar strategies were used by archaic humans exploiting both central and western europe in the light of microscopic studies of flint artefacts it seems that tools were of multipurpose use and some of them were hafted central europe shows evidence of punctuated habitation which resulted from gradual and natural expanding of the settlement ecumene during the periods of hospitable climatic conditions at present there is no evidence that the level of mobility was higher than in other parts of europe the conclusions are based on regional data from the analysis of a series of archaeological and geological sites combined with comprehensive studies of the hallera av site wroclaw poland the hallera av site is one of the best open air sites in central europe with an exploration area covering 800 m2 the multi seasonal excavation resulted in the discovery of numerous stone artefacts and faunal remains the conclusions are based on dating geological sedimentological studies spatial analysis and site formation processes combined with detailed multidisciplinary studies of artefacts and faunal remains

a new simple shear deformation apparatus for rocks and soils abstract we present a new design for a simple shear type deformation apparatus which has the capacity to deform medium strength anisotropic rocks as well as soils and similar strength materials the special feature of the design is that the deformation is achieved by the application of a particular set of boundary displacements so that a specimen is constrained to deform by a progressive simple shearing history these boundary displacements are applied through three pairs of steel platens each of which are in contact with opposite sides of the specimen which is initially a right rectangular prism one pair of platens is fixed so that deformations are plane strain a second pair of platens remains horizontal but they are free to slide against the reaction frame in the shear direction while at the same time they can apply a vertical normal force through hydraulic actuators the third pair of platens are vertical faces cut longitudinally through two steel shafts so that the shaft axes lie horizontally through the centre of the faces shear is applied by rotation of the two shafts so that the two vertical end faces of the specimen are rotated about the shaft axes this rotation means that horizontal planes in the specimen remain horizontal and suffer no shape change while vertical planes normal to the shaft axes remain vertical but suffer a shearing type change in shape the combination of these boundary displacements is a progressive simple shearing of the specimen we show typical stress strain responses for a number of different material types and discuss the degree of strain homogeneity throughout the specimen examples are presented of the microstructural changes which occur in specimens deformed in the apparatus

a 3 1 billion year old marble and the 87sr 86sr of late archean seawater a marble band in the 2 75 gyr old ramagiri schist belt in the dharwar craton of south india gave a pb pb age of 3 075 0 095 gyr the geochemical data including high sr and low ba and mn indicate seawater origin for the parent rock and that there was insignificant geochemical exchange between the marble and the surrounding rocks the calculated initial nd isotopic composition and 1 indicate an older continental crustal source for the nd and pb the initial 87sr 86sr of the marble is 0 70128 which is higher than the calculated mantle value at 3 ga although pre 3 gyr old marine carbonate rocks are thought to be buffered by mantle sr the ramagiri marble contains evolved crustal sr despite this the marble has the lowest measured 87sr 86sr among carbonates and represents one of the least radiogenic periods in seawater sr isotope composition

strontium isotope ratios in fossil teeth from south africa assessing laser ablation mc icp ms analysis and the extent of diagenesis abstract this study tests the precision and accuracy of laser ablation multi collector inductively coupled plasma mass spectrometry la mc icp ms for measuring strontium isotope ratios 87 sr 86 sr in fossil teeth from swartkrans and sterkfontein in south africa and explores the extent of diagenesis in these specimens compared to solution mc icp ms or thermal ionization mass spectrometry tims methods la mc icp ms can be faster and less expensive but has lower precision and accuracy we found that 87 sr 86 sr ratios in fossil rodent teeth measured by la mc icp ms were offset from solution values by a mean of 0 0005 0 0010 2 because of the very wide spread of biologically available 87 sr 86 sr ratios 0 710 to 0 790 in the region la mc icp ms is more than sufficient for assessing the geographic origins of the fossil rodents the concentration of strontium in modern and fossil enamel from the area is statistically indistinguishable as is the range of 87 sr 86 sr ratios in modern rodents and fossil rodents from swartkrans thus there is little evidence of diagenetic sr in the fossil enamel in contrast the fossil dentine may contain up to 50 diagenetic strontium although many dentine 87 sr 86 sr ratios are still far removed from the background cave value of 0 729 we propose that la mc icp ms will also be of use for investigating the geographic origins of other non rodent fossil teeth from the sterkfontein and swartkrans collections and may prove of similar utility at other suitable sites

frontal accretion along the western mediterranean ridge the effect of messinian evaporites on wedge mechanics and structural style in the context of the imerse project several crossings of the deformation front of the western mediterranean ridge were made in the region of the sirte abyssal plain the messina abyssal plain and the intervening region in this paper we present seismic images and interpretations across the deformation front with particular emphasis on the role the messinian evaporites have played in controlling the accretionary tectonics of the thin frontal portion of the wedge the seismic images show that the basal detachment generally is located at the base of the evaporites from a consideration of the mechanics of the wedge for both coulomb and plastic rheologies we show that the low wedge taper c 2 requires that the detachment is characterised by extreme fluid overpressuring within 2 of lithostatic in places and that the basal yield stress less than 1 mpa is lower than that of a wet salt decollement zone this supports the seismic interpretation that the detachment occurs in overpressured sediments beneath the impermeable evaporites lateral variations in the accretionary style can be related to lateral variations in evaporite thickness the effectiveness of the evaporite as an impermeable seal and to local relief on the subducting plate these factors control the escape of fluids from beneath the evaporites and hence fluid pressure and basal yield stresses

calcite texture development in experimentally induced ductile shear zones specimens of fine grained micritic limestone were deformed in plane strain geometry in pure shear a combination of simple and pure shear and in simple shear temperatures were 400 c and 500 c confining pressure was 100 mpa in the experiments with a simple shear component strain is concentrated and approximately homogeneous in a 2 3 mm wide shear zone shear displacement is documented by marker lines and circles shear strain varies between 0 84 and 1 56 strain is recorded by flattening of individual grains defining a foliation normal to the axis of principal finite shortening e1 no twinning is observed on a macroscopic scale

response to nowell and horstwood 2009 here we respond to the comment by nowell and horstwood 2009 written in response to our 2008 paper where we presented the first results of the application of laser ablation strontium isotope analysis to a fossil hominin although we are pleased that the paper has attracted so much interest including from researchers outside the field such as nowell and horstwood we completely disagree with the two main arguments of their comment namely we reject the notion that they can recalibrate our data using different methods and non matrix matched standards determined in a different laboratory and that is simply irresponsible to advocate the further development of this method for rare and important hominin samples through drilling rather than the almost non destructive method of laser ablation that we presented in our paper