first directional archaeomagnetic results from syria evidence from tell mishrifeh qatna summary we report on the first archaeomagnetic directional data obtained from syria reliable palaeomagnetic directions were collected from four pyrotechnological archaeological structures dated by type of pottery and radiocarbon from the 19th to 8th century bc middle bronze to iron age in tell mishrifeh qatna syria fairly constant northward declination values within confidence limits were obtained whereas inclination values increased from 42 3 to 73 0 from the middle bronze to iron age at first approximation these new data are consistent with coeval archaeomagnetic directions from western europe and bulgaria the high inclination 73 0 2 8 documented for the iron age translating to a vgp latitude of 65 9 n suggests that very strong secular variation was occurring during the 8th century bc

a german catalogue of archaeomagnetic data summary a catalogue has been compiled of existing published and unpublished archaeomagnetic directional data from sites in germany the data comprise 125 results dated mainly in the past two millennia the stability of the natural remanent magnetization was proven for most structures with at least a thellier viscosity test although for the majority of the data the direction is based on the characteristic remanent magnetization obtained from demagnetization experiments rock magnetic experiments carried out on the samples from many of the sites reveal that the dominant magnetic carrier is magnetite often oxidized or with impurities for many sites the archaeological age estimate is supported by physical dating methods while the roman epoch 0 400 ad and the period from medieval to modern times 800 1700 ad are reasonably well covered with data the time interval in between and the first millennium bc are only poorly covered the geographical distribution of data throughout germany shows a concentration along the rhine valley during roman times with in general a better coverage to the north nevertheless this data set clearly shows the secular variation during the past three millennia and it extends the european archaeomagnetic data set considerably

magnetic refraction studied on two experimental kilns summary experimental kilns in the form of shells half spheres and circular bottom plates inner radius 15 cm outer radius 17 cm were made from clay fire clay and less than 5 per cent by volume of fine grained haematite powder for the study of the effect of magnetic refraction in archaeological structures the haematite in the clay was reduced to a strongly magnetic phase maghematized magnetite the acquisition of trm was performed in a non magnetic gas heated furnace in the local geomagnetic field the kiln material has a maghemite ore content of about 2 per cent by volume and an apparent magnetic susceptibility at room temperature of about 4 x lo si units the deviations of the declination and inclination of the trm at different latitudes of the shells were respectively up to 40 and 15 and systematically dependent from the position of the specimens in the shell or bottom plate in agreement with model calculations however the classical approach for the magnetic refraction in materials with ferrimagnetic ore grains dispersed in a nonmagnetic rock matrix with simple assumptions for the demagnetizing fields of the ore grains and of the macroscopic sample was not able to explain the large refraction effects which have been observed an adequate theory for the magnetic refraction in rocks is still not available for archaeomagnetic studies some advice is offered for sampling and demagnetization treatment of the material in order to minimize refraction effects in archaeomagnetic data some consequences for palaeomagnetic studies are also discussed

estimate of the magnetic anisotropy effect on the archaeomagnetic inclination of ancient bricks abstract the magnetic fabric of 59 bricks coming from 5 ancient kilns has been studied by measuring the anisotropy of magnetic susceptibility ams and the anisotropy of isothermal airm anhysteretic aarm and thermal atrm remanent magnetization the bricks are characterized by a well developed magnetic fabric that matches their flat shape the shape of the anisotropy ellipsoids is in almost all cases oblate with the maximum and intermediate axes lying parallel to the large face of the brick and the minimum axis perpendicular to it the directions of the principal axes are almost the same irrespectively of the type of anisotropy measured whereas the degree of anisotropy of the airm aarm and atrm is much higher than the ams as the bricks lie horizontally within the kiln the planar magnetic fabric results in an inclination shallowing of the archaeomagnetic direction with respect to that of the earth s magnetic field at the time of their last cooling estimation of this effect on the grounds of atrm measurements yields a shallowing that varies from 4 to 10 for individual samples such inclination difference may significantly bias archeomagnetic dating for the case of the canosa late roman kiln it leads to a dating error of more than two centuries

geomagnetic secular variations 0 2700 yr bp recorded by lake sediments from waginger see southeastern bavaria summary a palaeomagnetic record of the geomagnetic secular variation during the last 2700yr has been obtained from four lake sediment cores from the waginger see bavaria 12 8 e 47 9 n in the northern foreland of the alps a time scale has been derived from pollen studies on one of the sediment cores investigations of susceptibility and intensity nrm have been used for stratigraphical intercore correlation throughout the period covered the main swings of declination and inclination records repeat well between the cores in general the palaeomagnetic records obtained agree with palaeolimnological and archaeomagnetic results from other european sites

the granny smith gold deposit the role of heterogeneous stress distribution at an irregular granitoid contact in a greenschist facies terrane the granny smith gold deposits formed late in the structural history of the yilgarn block at a high crustal level in a largely brittle structural regime gold mineralisation is located along a n s striking fault which wraps around the contact of a small granitoid intrusion in different sections of the fault mineralisation may be developed in the granitoid in the adjacent sedimentary sequence and or along the contact between them in the granitoid gold mineralisation is in conjugate networks of thin carbonate quartz veins and their alteration halos small displacements along veins are common in contrast veins and faults in the sedimentary rocks are subparallel to bedding spatial variations in the conjugate vein orientations indicate that the local stress field was heterogeneous and controlled by the shape of the granitoid contact the greatest variations in vein and implied stress orientations occur in zones where the contact is most irregular these are also the areas of richest mineralisation fluid flow was thus focused in a regional scale low mean stress region created by the geometry of the granitoid intrusion its irregular contact caused deposit scale variations in fluid flow and resulted in heterogeneous gold grades along the contact zone

further development of a theory of lee cyclogenesis abstract the purpose of this paper is to further develop and then apply the lee wave theory of lee cyclogenesis described by smith the two dimensional time dependent quasi geostrophic theory is shown to give closed form asymptotic solutions which clarify the cyclone growth mechanism and the catalytic influence of orography ageostrophic effects are considered and found to have little influence on the ice cyclone unless a low lying inertial wave critical layer is present when a rigid lid is added to the model thus allowing baroclinic instability a rapid two phase cyclone growth is found without a resonant orographic phase the unstable growth is small the theory is applied to three mountain ranges the alps the colorado rockies and the southern appalachians the results suggest that the iee wave model may be partially correct in the first two regions but problematic in the third

paleointensity of the geomagnetic field recovered on archaeomagnetic sites from france abstract twenty new paleointensity determinations have been obtained from archaeomagnetic sites from france time intervals investigated range from 65 to 380 ad and from 1370 to 1700 ad two hundred forty two samples of tiles and bricks were treated with the classical thellier method for paleointensity determination rock magnetic studies identify magnetite substituted maghemite and hematite as the main magnetic minerals as is usual with archaeomagnetic samples especially tiles magnetic anisotropy was observed in all samples the effect of thermoremanent magnetization trm anisotropy upon the paleointensity values was corrected after the determination of the tensor of trm anisotropy in each sample these determinations allow corrections of the field strength obtained which are usually lower than 20 the effect of the cooling rate on the trm intensity acquired was also determined and seems relatively low on our samples most frequently eight to 10 samples per site were used to calculate the mean intensity standard deviations are typically lower than 7 of the average value during the roman period small variations of the field intensity in paris are observed between 62 and 70 t while during the more recent period the intensity of the field decreases from 62 to 52 t an analysis of the paleointensity data available for the last 2000 years obtained from sites in western europe was performed using a weighing factor which takes into account the number and type of the samples studied as well as the technique used for the paleointensity determination this weighing factor clearly shows that most of the existing data might not be reliable the analysis performed indicates that more data is needed especially from the time interval 500 to 1400 ad before it would be possible to determine a reference curve of the time variations of the archaeomagnetic intensity of the field in western europe

investigating the expected archaeomagnetic dating precision in europe a temporal and spatial analysis based on the scha dif 3k geomagnetic field model abstract archaeomagnetic dating is a chronometric dating technique based on the ability of baked clay archaeological structures and artifacts to acquire a thermal remanent magnetization trm when heated at high temperatures and cooled in the presence of the earth s magnetic field the precision of archaeomagnetic dating depends on several factors among others the availability of a detailed reference secular variation sv curve for a given territory in this study we investigate the precision that archaeomagnetic dating can reach in europe we used the scha dif 3k european geomagnetic field model to calculate the dating uncertainties for the last 3000 years taking into consideration only the uncertainties depending on the change rate of the geomagnetic field in the past and the reference sv curve s uncertainty envelope such uncertainties were calculated both in time and space they are usually asymmetrically distributed around the considered year and it have been represented as dynamic maps of uncertainties the obtained results show that archaeomagnetic dating based solely on directional data declination and inclination can be very precise for the last four centuries with total uncertainties being almost always lower than 100 years all around europe inherent dating uncertainties are also low for the last millennium with values ranging from 50 to 300 years these results underline the great potential of archaeomagnetism on dating baked clays belonging to the last 1000 years for older periods the uncertainty maps show that the dating precision may importantly vary from place to place but with local non symmetric uncertainty ranges generally below 400 years the obtained maps also show that adding the intensity to the computation of the inherent uncertainties does not always reduce the uncertainty the temporal and spatial analysis presented here does not give the total dating imprecision of archaeomagnetic dating that definitely depends on numerous often uncontrollable factors but aims at offering a useful tool to archaeomagnetic and archaeological research to check the feasibility of archaeomagnetic dating for determining the age of an archaeological structure below a desired precision

rock magnetic analyses as a tool to investigate archaeological fired sediments a case study of mirador cave sierra de atapuerca spain summary here we report a detailed mineral magnetic study of neolithic burnt levels in the mirador cave sierra de atapuerca burgos spain to reconstruct the burning history and to investigate their suitability for archaeomagnetic purposes as a consequence of the ancient burning a characteristic facies sequence was developed along the holocene stratigraphy from top to bottom it includes i 2 10 cm ash layers ii 2 cm underlying rubefied layers and iii clay mainly unburnt and of variable thickness in some cases a thermally altered facies 2 6 cm with a heterogeneous texture was identified facies tf usually between rubefactions and the unburnt levels 126 oriented samples from 4 units mir12 15 18 and 21 and a 2 m section all comprised between units mir21 6380 40 14c bp and mir9 5090 40 14c bp were analysed with rock magnetic methods in addition bulk sediment from each facies that comprise the neolithic sequence was investigated measurements included stepwise alternating field and thermal demagnetization of natural remanent magnetization nrm viscosity experiments determination of the anisotropy of the magnetic susceptibility ams the susceptibility frequency dependence at room temperature and determination of the temperature dependence of the susceptibility additional experiments consisted in the determination of the behaviour of anhysteretic and isothermal irm remanences magnetic hysteresis loops first order reversal curve diagrams and thermal demagnetization of three axial irm it appeared that the facies all show a fairly similar magnetic mineralogy and grain size dominated by low titanium magnetite that is often partially maghaemitized main differences constitute the amount of superparamagnetic particles that is higher in unburnt strata concurring with a less well defined nrm behaviour the magnetic mineral concentration is notably higher in ashes this homogeneity strongly suggests that similar sources and burial conditions prevailed during neolithic times agreeing with archaeological observations and favoured by rapid burial conditions very limited alterations have been deduced ams data revealed the absence of fluid flow in the ash lenses sampled demagnetization revealed a stable single nrm component in ashes a single or two component nrm in rubefactions and less stable multicomponent behaviour in clays in ashes magnetic minerals are likely secondary in origin formed by low temperature oxidization soon after burning although this thermochemical nature of the nrm invalidates the use of these sediments for palaeointensity studies archaeomagnetic directional data can be successfully obtained because the burning and oxidation are closely confined in time

geomagnetic palaeosecular variation 0 13 000 yr bp as recorded in sediments from three maar lakes from the west eifel germany summary geomagnetic palaeosecular variation psv profiles have been obtained from 12 cores raised from three maar lakes in the west eifel germany age control is provided by varve chronology analysis of mean inclinations suggests that a post depositional remanent magnetization pdrm was acquired in all three lakes a lock in time of 150 yr corresponding to an average lock in depth of 24 cm has been determined from a comparison with archaeomagnetic sv data stacked psv results demonstrate directional geomagnetic field behaviour through the late and post glacial in central europe and show good agreement with the holocene british master curve turner thompson 1982 psv results suggest that westward drift of the non dipole field was not persistent over the last 13 000 yr spectral analyses yield declination variations with durations of about 1800 yr in the younger holocene 0 5000 yr bp and 4300 yr between 5000 and 13 000 yr bp the inclination exhibits swings of 1000 yr duration in the younger holocene and about 2000 yr in the older part moreover inclination spectra suggest the presence of one inclination variation with a very long duration approaching the length of the time span investigated 8600 yr

an updated and homogeneous world secular variation data base 1 smoothing of the archaeomagnetic results the available original archaeomagnetic world data on intensity and direction have been compiled and sorted according to geographical region then after correcting them to correspond to a single site associated with each region called a world site they have been processed using the gaussian statistic for the intensity f data and bivariate statistic for the declination d and inclination i data to obtain smoothed values at regular time intervals we include a discussion of the statistical methods used we have limited the data to the last 20 centuries because the archaeomagnetic data alone do not allow us to go back further in the past we have also excluded archaeomagnetic studies at world sites where the number of data is not sufficient to perform a statistical analysis we obtained results at nine world sites for which the values of at least two of the three above quoted parameters have been calculated at 25 year intervals from the beginning of our era the results for each world site with their associated errors are given and discussed the potential of this new set of world data for improving our knowledge of the global terrestrial magnetic field tmf during the past 20 centuries is sketched these results will be completed in a second paper by analysing in the same way the data supplied for volcanic rocks and lake sediments

pre columbian mural paintings from mesoamerica as geomagnetic field recorders 1 this paper reports a reconnaissance archeomagnetic study of mural paintings in various pre columbian sites in mexico the magnetic measurements of the pigments show that at least four murals sites cacaxtla cholula and templo mayor retain a remanent magnetization carried by a mixture of magnetite and minor hematite grains in most specimens a characteristic remanent magnetization is successfully isolated by alternating field demagnetization the mean directions are reasonably well determined for each mural and within the range of secular variation during the last centuries studied mesoamerican murals apparently retain the direction of the magnetic field at the time they were painted and therefore are an invaluable source of information concerning its secular variation the archeomagnetic study of pre columbian mural paintings opens new alternatives to drawing a reliable reference master curve for the region and may largely contribute to the mesoamerican absolute chronology

a catalogue of spanish archaeomagnetic data a total of 58 new archaeomagnetic directions has been determined from archaeological structures in spain together with five previous results they allow the compilation of the first archaeomagnetic catalogue for spain which includes 63 directions with ages ranging between the 2nd century bc and the 20th century ad characteristic remanence directions have been obtained from stepwise thermal and alternating field demagnetization the hierarchical structure has been respected in the calculation of the mean site directions rock magnetic experiments reveal that the main magnetic carrier is magnetite or titanomagnetite with different titanium contents the age estimate of the studied structures is generally well justified by archaeological constraints for six structures the proposed date is also supported by physical methods the data are in close agreement with the french secular variation sv curve this catalogue represents the first step in the construction of a sv curve for the iberian peninsula which will be of much use in archaeomagnetic dating and in modelling of the earth s magnetic field in western europe

a preliminary secular variation reference curve for archaeomagnetic dating in austria the construction of a secular variation sv reference curve for a region for which little or no archaeomagnetic directions are available is presented here a sv curve is illustrated for austria centred on radstadt 47 38 n 13 45 e and based on data from sites in other countries less than 500 km away the published data were selected on site characteristics of n 3 and k 50 and dated within 400 yr this yielded 170 directions from which a sv curve was derived using bayesian techniques the obtained reference curve represents the past 2300 yr new data mainly from austria substantiate this curve and confirm the validity of the techniques employed which can therefore be applied for similar situations another test has been made using the german reference curve for dating the austrian archaeological sites here a systematic shift to older times in the order 30 110 yr occurs

intensity of the earth s magnetic field in greece during the last five millennia new data from greek pottery abstract new archaeointensity results have been obtained from the study of four ceramic collections coming from four different archaeological sites in greece the ages of the ceramic fragments based on archaeological constrains and radiocarbon analysis range from 2200 bc to 565 ad low field magnetic susceptibility versus temperature reveals a good thermal stability for most of the samples however for some samples the thermomagnetic curves are not reversible indicating mineralogical changes during heating isothermal remanent magnetisation irm acquisition curves and thermal demagnetisation of three orthogonal irm components have also been performed the rock magnetic results identify magnetite and or ti magnetite as the main magnetic carriers in the studied samples classical thellier experiments with regular partial thermoremanent magnetisation ptrm checks have been conducted on 125 specimens belonging to 34 independent ceramic fragments only 61 archaeointensity determinations at specimen level that correspond to linear nrm trm plots were used for the calculation of the site mean archaeointensities the effect of the anisotropy of the thermoremanent magnetisation trm and cooling rate upon trm intensity acquisition have been investigated in all specimens the maximum difference between the trm anisotropy corrected and uncorrected intensities is around 30 at specimen level confirming that the trm effect can be very important in ceramic samples cooling rate correction factors determined per specimen are up to 10 with only one exception that reaches 35 despite the moderate success rate of archaeointensity determination around 50 reliable mean site intensities have been obtained with in situ intensities ranging from 53 6 4 1 to 69 3 3 9 t corresponding to virtual axial dipole moments from 9 2 0 7 to 11 9 0 7 10 22 am 2 the new data are reasonably consistent with other available data for the studied region as well as with the sv reference curves for greece and the south balkan peninsula and the regional and global geomagnetic field models combined with previously published data from the area they confirm that important changes of the earth s magnetic field intensity occurred in greece during the last five millennia for some periods the available archaeointensity data for the balkan area show a large dispersion even for data corresponding to high quality intensity standards whereas for other periods their limited number prevents an accurate description of geomagnetic field intensity changes this evidences the need of new reliable and well dated archaeointensity data in order to obtain a robust description of geomagnetic field intensity changes during the last five millennia in this area

new archaeointensity data from italy and geomagnetic field intensity variation in the italian peninsula we present new archaeointensity results from three italian kilns situated at ascoli satriano vagnari and fontanetto po obtained with the thellier modified by coe double heating method these data complement the directional results previously published all sites are dated on the basis of archaeological information and or thermoluminescence dating the results are corrected for the anisotropy of the thermoremanent magnetization and the cooling rate effects the new data are compared with previously published archaeointensity data from italy and nearby countries within 900 km radius from viterbo an initial data set including archaeointesity data mainly coming from italy france switzerland czech republic slovakia hungary greece and bulgaria has been compiled after the application of strict selection criteria the most reliable data have been used for the calculation of a preliminary italian intensity secular variation sv curve for the last 3000 yr the new curve covers the 300 bc 400 ad and 1200 1900 ad periods it is established by means of sliding windows of 200 yr shifted by 100 yr the lack of reliable data for the 1000 200 bc and 400 1200 ad time intervals does not permit the calculation of a continuous curve clearly more high quality archaeointensity data from italy and europe are still needed to draw a robust intensity sv curve for the italian peninsula that could be used for archaeomagnetic dating in combination with the directional data

paleomagnetic directions and thermoluminescence dating from a bread oven floor sequence in lubeck germany a record of 450 years of geomagnetic secular variation 1 a record of about 450 years of geomagnetic secular variation is presented from a single archaeological site in lubeck germany where a sequence of 25 bread oven floors has been preserved in a bakery from medieval times until today the age dating of the oven floor sequence is based on historical documents 14c dating and thermoluminescence dating it confines the time interval from about 1300 to 1800 a d paleomagnetic directions have been determined from each oven floor by means of 198 oriented hand samples after alternating field as well as thermal demagnetization experiments the characteristic remanent magnetization direction was obtained using principal component analysis the mean directions of 24 oven floors are characterized by high fisherian precision parameters 146 and small 95 confidence limits 1 2 4 6 for obtaining a smooth curve of geomagnetic secular variation for lubeck a spherical spline function was fitted to the data using a bayesian approach which considers not only the obtained ages but also stratigraphic order correlation with historical magnetic records suggests that the age estimation for the upper 10 layers was too young and must date from the end of the sixteenth to the mid of the eighteenth century for the lowermost 14 layers dating is reliable and provides a secular variation curve for germany the inclination shows a minimum in the fourteenth century and then increases by more than 10 declination shows a local minimum around 1400 a d followed by a maximum in the seventeenth century this is followed by the movement of declination about 30 to western directions

theory and application of the day plot mrs ms versus hcr hc 2 application to data for rocks sediments and soils 1 new theoretical curves relating the hysteresis parameters mrs ms and hcr hc for single domain sd superparamagnetic sp pseudo single domain psd and multidomain md grains and their mixtures are applied to published data for natural materials the day plot of mrs ms versus hcr hc has been used to crudely classify samples into box like sd psd and md or sometimes incorrectly md sp regions with arbitrary boundaries new type curves for md psd sd md and sd sp grains and mixtures permit more subtle and precise modeling the predicted md trend and its junction with the psd trend are observed in two data sets for magnetite spherules from carbonate rocks and for temperature varying hysteresis results spanning the verwey transition the latter data are the basis of a suggested new method for pinpointing the psd md threshold size selected data for pottery clays soils and paleosols generally follow sd md type curves and indicate intermediate size psd magnetite with narrow to broad size distributions a lake sediment section with known grain size progression tracks in the predicted sense along the sd md trend selected data for glaciomarine and pelagic sediments are also generally compatible with sd md trends examples of remagnetized carbonate rocks submarine basaltic glasses and glassy rims of pillow basalts all follow predicted sp sd or sp psd mixing curves with a large range in volume fraction of sp grains 0 75 but a narrow range of sp particle sizes 10 2 nm larger sp grains spanning the range to sd size 25 30 nm are absent for unknown reasons oceanic dolerites gabbros and serpentinized peridotites in some cases fall in a novel region of the day plot parallel to but below magnetite sd md mixing curves

distribution analysis of errors due to relocation of geomagnetic data using the conversion via pole cvp method implications on archaeomagnetic data summary secular variation master curves are built up using geomagnetic historical observations or archaeomagnetic data from a limited area and their use is usually restricted to regions of around 1000 km radius relocation of data within this distance is a common practice to enable comparison of data although the errors due to such process are rarely taken into account a detailed analysis of the distribution of relocating geomagnetic data has been done using three popular sets of geomagnetic models igrf 9 gufm and cals7k 2 this study improves the error analysis of relocating geomagnetic directions made up to date and expands it to geomagnetic intensities maximum errors correlate with the non dipole to dipole field ratio archaeomagnetists could use this analysis to valuate the error introduced by reducing data

three millennia of directional variation of the earth s magnetic field in western europe as revealed by archeological artefacts directional secular variation of the geomagnetic field over the last 2000 years has been defined in western europe from numerous archeomagnetic studies however the number of archeomagnetic results for older periods is much more limited for this reason we present new data obtained from fired archeological structures found in two french sites loupiac and aspiran dated within the first millennium b c latest bronze earliest iron age transition 850 700 b c and iron age 525 475 b c respectively from a compilation of archeomagnetic results from western europe great britain italy and france and northern africa tunisia we propose a directional secular variation curve for western europe that covers the entire first millennium b c this curve exhibits a large clockwise motion with rapid changes during the first half of the millennium while the last four centuries b c are characterized by weak variations

widespread occurrence of a novel high coercivity thermally stable low unblocking temperature magnetic phase in heated archeological material 1 the widespread occurrence of a novel high coercivity magnetic phase in well heated archeological material is reported its properties are defined when it represents the dominant magnetic phase although it is nearly always found as part of a mixture of magnetic phases they are as follows very high coercivity remanence coercivity 600 mt low unblocking temperatures 200 c and high degree of thermal stability this last property distinguishing it from goethite the phase shows striking similarities to magnetic phases produced by thermal decomposition of nontronite an fe rich clay where decomposition occurs after prolonged heating in air to high temperatures conditions suffered by well heated archeomagnetic material preliminary results of mossbauer and x ray diffraction spectroscopy suggest that the phase is more likely to be a substituted hematite rather than fe cristobalite or a variant of fe2o3

combination of archaeomagnetism and thermoluminescence for precision dating abstract archaeomagnetic dating was applied to two chalk burning ovens from an early medieval noble cemetery usually this method allows dating by the investigation of the geomagnetic declination and inclination through the thermoremanent magnetisation of baked clay in situ however in this case the method resulted in multiple dates since it was not possible to distinguish the brainching of the geomagnetic secular variation curve thermoluminescence dating was applied to the same samples to overcome the problem of multiple dates this first combined application of archaeomagnetism and thermoluminescence for dating yielded a d 670 30 for the two ovens which dates the first stone church at the site after a wooden predecessor archeologically dated a d 620 630

continuous geomagnetic field models for the past 7 millennia 1 a new global data compilation 1 a global data set of archeomagnetic and paleomagnetic data covering the past 7000 years has been compiled it consists of 16 085 results of inclination 13 080 of declination and 3188 of intensity for the time span 5000 bc to 1950 ad declination and inclination data come partly from existing databases and partly from original literature a new global compilation of intensity data for the millennial scale is included data and dating uncertainties are discussed as we attempted to obtain an internally coherent data set the global distribution of the data is very inhomogeneous in both time and space all the data are compared to predictions from the previous 3000 year global model cals3k 1 this collection of data will be useful for global secular variation studies and geomagnetic field modeling although southern hemisphere data are still underrepresented in particular we will use it in a further study to update and extend the existing global model cals3k 1 the huge increase in data compared to the previous compilation will result in significant changes from current models as we might have missed some suitable data we encourage the reader to notify us about any data that have not been included yet and might fit in as improving our global millennial scale models remains our aim for the future the data files described in this paper are available from the earthref digital archive erda at http earthref org cgi bin erda cgi n 331

high coercivity remanence in baked clay materials used in archeomagnetism a study of the high coercivity remanence in archeological baked clays has been carried out more than 150 specimens from 46 sites across europe have been analyzed selected on the basis of the presence of a fraction of their natural remanence that was resistant to alternating field demagnetization to 100 mt the study was based on the stability of isothermal remanence to alternating field and thermal demagnetization and its variation on cooling to liquid nitrogen temperature results indicate that the high coercivity remanence may be carried by magnetite hematite and in isolated cases partially oxidized magnetite and goethite in addition a high coercivity thermally stable low unblocking temperature phase has been identified the unblocking temperatures of both the isothermal remanence and the alternating field resistant natural remanence exhibit similar unblocking temperatures suggesting that the same phases carry both signals the high coercivity low unblocking temperature phase contributes to the natural remanence sometimes carrying a stable direction and behaving ideally during palaeointensity experiments and sometimes not an unambiguous mineralogical identification of this phase is lacking although likely candidates include hemoilmentite related to clay source lithology and substituted hematite or magnetic ferri cristabolite both possible products of thermal transformation of iron bearing clays

the earth s magnetic field in italy during the neolithic period new data from the early neolithic site of portonovo marche italy we present new full geomagnetic field vector results from three neolithic ovens discovered at the archaeological site of portonovo marche italy the discovered structures are a rare example of very well preserved underground ovens from the early neolithic period standard thermal demagnetization procedures were used to isolate the direction of the characteristic remanent magnetization acquired by the baked clay during the ovens last firing the corresponding archaeointensities were determined by the multi specimen procedure msp dsc and show a clear intensity low during the neolithic period both directional and intensity results are of high quality offering the first contribution of full geomagnetic field vector data for this period in italy the new data are compared with other contemporaneous data from europe and with global geomagnetic field models independent archaeomagnetic dating of the three ovens was also performed by means of the scha dif 14k model the obtained results are in excellent agreement with available radiocarbon dates and confirm that all ovens belong to the neolithic these new data importantly enrich our knowledge of the geomagnetic field during the neolithic period that is poorly documented by data not only in italy but also in the whole of europe and show that archaeomagnetic dating can provide precise results even for prehistoric periods

new archeomagnetic secular variation data from central europe ii intensities abstract variations of the geomagnetic field during the past millennia can be obtained by investigating archeological material the spatial distribution of the available data across europe is rather uneven and only about 15 of the sites provide a full vector record of the geomagnetic field here we report 39 new reliable paleointensity data for sites from austria germany and switzerland with ages ranging between 1500 bce and 1900 ce for 31 of them directional information is available too paleointensities were determined with thellier type techniques with the multiple specimen domain state corrected paleointensity protocol or with both techniques corrections for anisotropy of thermoremanent magnetization were carried out for the structures showing small variations of only a few per cent in most cases cooling rate dependence was tested for 16 structures often strong alteration during the experiments was observed seven successful cooling rate corrections were applied which lowered the paleointensity values by about 10 values obtained from the multiple specimen technique are generally somewhat lower than those from the thellier experiments rock magnetic measurements revealed magnetite type minerals mostly in pseudo single domain range as main magnetic carrier but also high coercive mineral components like hematite or epsilon iron oxide are present the new data are mostly in good agreement with published paleointensities they support the presence of strong intensity variations around 800 ce and in the millennium bce the new full vector data reveal that the deep paleointensity minimum observed from german data around 850 bce is accompanied by large variations in direction with declinations up to 50