hafted armatures and multi component tool design at the micoquian site of inden altdorf germany abstract excavation of the micoquian site inden altdorf weisweiler 124 near the former german capital bonn in western germany has revealed the first valid open site habitation features with hut like structures and associated hearths for the middle palaeolithic in central europe it has been dated to the eemian interglacial ois 5e a warm interglacial between 128 and 115 ka bp various wear traces and especially organic residues have been detected on a large number of stone tools using microscopic use wear analysis of lithics recovered from the site a multi level analysis developed through an experimental framework and archaeological study using optical light microscopes scanning electron microscopes and energy dispersive x ray microprobes identified the adhering residues as birch pitch birch pitch is the oldest synthetically produced material and was used as an adhesive to attach lithic implements to wooden shafts while such hafting technology is commonly associated with modern humans in the upper palaeolithic the birch pitch residues found on the micoquian tools of inden altdorf suggest that hafting technologies and the frequent use of multi component tools already existed in the middle palaeolithic c 120 ka bp in central europe

mountain building and earth rotation summary whereas the present day true polar wander and the secular non tidal acceleration of the earth have usually been attributed to postglacial rebound it has recently been suggested that non glacially induced vertical tectonic movements taking place under non isostatic conditions can also be effective in changing the earth s rotation we present a case study in which we analyse the effects of some simple uplift histories of the himalayas and the tibetan plateau on the rotational axis and on the second degree zonal harmonic of the geoid for time scales of up to a few million years we first assume a permanent amount of overcompensation which is consistent with observed geoid anomalies over the himalayas and then we model by means of the normal mode techniques the viscous relaxation in the mantle with the elastic lithosphere supporting elastically 2 per cent of isostatic disequilibrium in our normal mode analysis the earth is divided into five layers an effectively elastic lithosphere a viscoelastic shallow upper mantle transition zone and lower mantle characterized by the maxwell rheology and an inviscid core the readjustment of the equatorial bulge due to viscous flow in the mantle is taken into account in our studies by solving the linearized liouville equations for the conservation of angular momentum via the love numbers formalism polar wander is sensitive to the rate of relaxation of the modes m1 and m2 due to the discontinuities between the three mantle layers positioned at 420 and 670 kilometres depth the rate of readjustment is sensitive to the viscosity of the transition zone whenever the lower mantle shallow upper mantle viscosity ratio is small the highest present day velocity of polar wander due to himalayan and tibetan plateau uplift is estimated to be 1 myr 1 for an isoviscous mantle that has the same magnitude of the observed value reduced to 0 1 myr 1 for a factor 50 viscosity increase in the lower mantle these numbers are about the same as those found from postglacial rebound that occurs on the short time scale of a thousand years instead of the million years of our analysis but represent upper bounds for mountain building obtained only in the case in which a permanent deviation from isostasy of at least 2 per cent is assumed in general the proposed mechanism is less efficient in driving long term rotation instabilities than deep seated processes characterized by the same time scale of a million years such as subduction polar wander velocity is extremely sensitive to the depth of the uncompensated anomalous root of the topography for the models in which full mantle relaxation is allowed

haskell 1935 revisited the haskell 1935 value of 1021 pa s for mantle viscosity is a classic and enduring constraint on the rheology of the earth s interior we revisit this inference using spherically symmetric self gravitating maxwell viscoelastic earth models our inference is based on both forward and inverse analyses of decay times associated with uplift at two sites considered by haskell angerman river sweden and oslo norway rather than the raw relative sea level rsl data at these sites we demonstrate that predictions of the decay time associated with the angerman river data are insensitive to variations in both the late pleistocene ice load history and the lithospheric thickness of the earth model the predictions at oslo are sensitive to both these inputs and hence decay times at this site provide a remarkably robust constraint on mantle viscosity we derive a constraint on the average viscosity of the mantle of 0 65 1 10 1021 pa s where the average resolved by the data encompasses a region which extends from the base of the lithosphere to a depth of near 1400 km this indicates that many previous analyses which have invoked the haskell value of 1021 pa s as a constraint on the average upper mantle i e above 670 km depth viscosity alone have misinterpreted the resolving power of the inference furthermore our analysis indicates that a number of apparently contradictory inferences of viscosity based on fennoscandian data satisfy the new rigorous interpretation of the haskell constraint finally we demonstrate how the ambiguity in the upper mantle lower mantle viscosity contrast associated with the haskell average may be reduced by invoking decay time constraints estimated from rsl curves in hudson bay a preliminary inversion of decay times at angerman river and richmond gulf in hudson bay suggests a contrast of approximately an order of magnitude between the average viscosities of the upper mantle and the top 1000 km of the lower mantle however a conclusive analysis in this regard must await the determination of consistent decay time estimates for the hudson bay region

identification and evaluation of post depositional mechanical traces on quartz assemblages an experimental investigation abstract the evaluation of the state of preservation of archaeological lithic artefacts is the first step before starting a functional analysis if lithic artefacts show a variety of damage from many contact materials they are also subject to modifications from natural causes such as water transport soil abrasion trampling etc studying alteration features gives us information to reconstruct the life story of lithic tools after their abandonment and helps us to better understand formation processes of archaeological sites prolonged movements under soil could be responsible for post depositional surface modifications that sometimes look like wear traces due to use these alterations could have chemical and or mechanical origin recognizing them is of paramount importance especially on quartz assemblages where usewear analysis requires a long and complex methodology that differs to a certain extent from the protocol applied to other artefacts produced with different raw materials such as flint obsidian etc for this reason the use wear and post depositional surface modification analysis on quartz and quartzite tools have been undertaken by very few researchers until now the aim of this paper is to increase the experimental quartz field through the attempt to recreate mechanical contact between quartz flakes and sediments such as in archaeological contexts through the use of a polishing machine mecapol p320 equipped with two counter rotating platens it was possible to wear out two experimental flakes in a sandy quartzite sediment coming from sai island sudan for 240 h after the experimentation the two flakes showed no edge damage or other visible modifications but some micro traces on the crystal surface were present although long and demanding this step sharply reduces possible errors in the recognition of use wear during the experimental stage the micro traces definable as abrasions on some parts of the crystal surface have been analysed by a metallographic microscope and compared with the same crystal portion taken before the experiment even if it is difficult to reconstruct post depositional processes in a laboratory this attempt shows that the contact between sediment and stone tools in a continuous movement can randomly abrade the crystal surface

first molecular identification of a hafting adhesive in the late howiesons poort at diepkloof rock shelter western cape south africa abstract the hafting of tools using adhesive is one of the innovative features that characterizes the southern african middle stone age this technology has mainstream implications but remains insufficiently documented largely due to unequal organic preservation and non adapted analytical procedures a notable exception is provided by the recent results from the site of sibudu lombard 2006 wadley et al 2009 the excavation at diepkloof rock shelter has revealed several lithic artifacts with a black residue distributed over their surface their stratigraphic distribution reveals a strict association with the howiesons poort hp and suggests a close relationship between the appearance of hafting adhesive and the appearance of blades and geometric backed tools macroscopic and microscopic observations attest to a hafting that was exclusively lateralized and preliminary use wear analysis igreja and porraz in this issue supports the hypothesis that hafted tools were mostly integrated within daily domestic activities in this study we focused specifically on a chemical study of a thick black residue found on a quartz flake attributable to the late phase of the hp we determine for the first time in a msa context the nature of the compound adhesive and reconstruct a picture of the multilevel operations and interactions that comprise the process of hafting the molecular analysis attests to the exploitation of podocarpus elongatus yellowwood collected in the form of a resin that was naturally dried or heated at a low temperature and possibly mixed with fragmented bone and quartz grains compared to sibudu where ochre additive is documented the hafting technology at diepkloof introduces another level of variability within the hp tradition and suggests the existence of regional expressions and adaptations

global geodetic signatures of the antarctic ice sheet four scenarios of present day antarctic ice sheet mass change are developed from comprehensive reviews of the available glaciological and oceanographic evidence the gridded scenarios predict widely varying contributions to secular sea level change ranging from 1 1 to 0 45 mm yr and predict polar motion and time varying low degree gravitational coefficients that differ significantly from earlier estimates a reasonably linear relationship between the rate of sea level change from antarctica a and the predicted antarctic is found for the four scenarios this linearity permits a series of forward models to be constructed that incorporate the effects of ice mass changes in antarctica greenland and distributed smaller glaciers as well as postglacial rebound assuming the ice 3g deglaciation history with the goal of obtaining optimum reconciliation between observed constraints on and sea level rise numerous viable combinations of lower mantle viscosity and hydrologie sources are found that satisfy observed in the range of 1 to 2 2 5 mm yr and observed for degrees 2 3 and 4 in contrast rates of global sea level rise above 2 5 mm yr are inconsistent with available observations the successful composite models feature a pair of lower mantle viscosity solutions arising from the sensitivity of to glacial rebound the paired values are well separated at mm yr but move closer together as is increased and in fact merge around 2 2 5 mm yr revealing an intimate relation between and preferred lower mantle viscosity this general pattern is quite robust and persists for different solutions for variations in source assumptions and for different styles of lower mantle viscosity stratification tighter constraints for l 2 may allow some viscosity stratification schemes and source assumptions to be excluded in the future for a given total observed the sea level rise from antarctica a is tightly constrained and ranges from 0 to 1 mm yr corresponding to an ablating ice sheet as estimates of are raised from 1 to 2 5 mm yr however when the degree 3 zonal harmonic constraint is removed the solutions show little sensitivity to antarctic mass balance emphasizing the need for a well determined odd degree secular zonal harmonic for determining polar ice mass balance

pleistocene deglaciation and the earth s rotation implications for mantle viscosity summary recent results from the analysis of postglacial rebound data suggest that the viscosity of the earth s mantle increases through the transition region models which fit both relative sea level and free air gravity data have viscosities which increase from a value near 1022 poise in the upper mantle beneath the lithosphere to a value of about 1023 poise in the lower mantle in this paper we analyse the effect of deglaciation upon the earth s rotation and thereby show that the observed secular trend polar wander evident in the ils ipms pole path and measurements of the non tidal acceleration of the length of day are both consistent with the viscosity profile deduced from postglacial rebound the two analyses are therefore mutually reinforcing

radial profile of mantle viscosity results from the joint inversion of convection and postglacial rebound observables we present new inferences of the radial profile of mantle viscosity that simultaneously fit long wavelength free air gravity harmonics associated with mantle convection and a large set of decay times estimated from the postglacial uplift of sites within previously glaciated regions hudson bay arctic canada and fennoscandia the relative sea level variation at these latter sites is constrained by age height pairs obtained by geological survey rather than the subjective trends which are commonly used in glacial isostatic adjustment gia studies our viscosity inferences are generated using two approaches first we adopt a relative viscosity profile which is known to provide a good fit to the free air gravity harmonics and determine an absolute scaling which yields a best fit to the gia decay time constraints second we perform an iterative nonlinear joint inversion of the two data sets in both cases our inferred profiles are characterized by a significant increase of viscosity 2 orders of magnitude with depth to values of 1022 pa s in the bottom half of the lower mantle the new viscosity profiles are shown to satisfy constraints based on the postglacial uplift of both fennoscandia the classic haskell 1935 number and hudson bay which have commonly been invoked to argue for an isoviscous mantle furthermore the models are used to predict a set of long wavelength signatures of the gia process these include predictions of gia induced variations in 1 the length of day over the late holocene period 2 the earth s precession constant and obliquity over the last 2 6 myr and 3 the present day zonal harmonics of the geopotential jl l 7 the predictions 1 and 3 bound the late holocene and ongoing mass flux between the large polar ice sheets greenland and antarctic and the global oceans to small values 0 4 mm yr equivalent eustatic sea level rise

mantle viscosity inferences from joint inversions of pleistocene deglaciatio induced changes in geopotential with a new slr analysis and polar wander joint inversions of post glacial rebound induced secular changes in low degree harmonics of the geopotential and true polar wander tpw systematically indicate that the upper mantle viscosity has a value that is considerably smaller than 10 21 pas the lower mantle viscosity is about one order of magnitude larger than the upper mantle viscosity discrepancies in the viscosity profiles inferred from even and odd zonals are likely an indication of recent unmodeled glacial forcings and or insufficient precision in the evaluation of the mass loss from pleistocene ice sheets the influence of systematic errors in slr data reduction due to thermal drag on the lageos satellites for the uneven zonals of the geopotential is avoided by making use of the starlette and stella satellites to recover the uneven zonals and by considering lumped coefficients for these uneven terms

some preliminary observations on subsurface damage on experimental and archaeological quartz tools using clsm and dye abstract lithic use wear analysis mainly deals with use wear features which can be observed on the surface of stone tools but a major part of the wear of brittle material is found under the surface this wear might also be a clue to the interpretation of archaeological stone tools in this paper we try to examine subsurface damage on experimental and archaeological quartz tools by dying them with fluorescent colour and scanning them with a clsm this method shows that various worked materials cause different subsurface damage which is related to the hardness of the worked material

an experimental case of bone working usewear on quartzite artifacts abstract usewear analysis has become an essential method for studying function of lithic artifacts this article discusses experiments and analyses of usewear on quartzite artifacts caused from bone working the raw materials were collected from the wulanmulun site inner mongolia north china four working motions were involved including cutting scraping drilling and chopping five specimens were selected for a multi stage experiment this experiment demonstrates that apparent usewear would occur on the employable location on specimens as follows 1 mainly large and medium scarring sizes 2 mainly stepped and feathered terminations and hinged ones occasionally 3 continuous and overlapped distributions 4 heavy rounding on the used edges of specimens the multi stage experiment shows that the number of newly produced scars declined with time duration and intensity of usage the development of rounding shows a non linear increase from light to heavy this article intends to establish a reference collection of lithic usewear on chinese quartzite for archaeological analyses

isostatic deformations and polar wander induced by redistribution of mass within the earth the effects at the surface of the earth of time dependent mantle mass anomalies are analyzed within the framework of a viscoelastic mantle with maxwell rheology the implications for the earth s rotation are developed using the linearized liouville equations valid for small polar displacements our approach is appropriate for a simplified modeling of subduction the displacement of the earth s axis of rotation called true polar wander is very sensitive to the viscosity profile of the mantle and to the nature of the 670 km seismic discontinuity phase change models generally yield a huge amount of polar wander except for large viscosity increases for chemically stratified models true polar wander is drastically reduced as a consequence of dynamic compensation of the mass anomalies at the upper lower mantle interface when the source is embedded in the upper mantle in the proximity of the chemical density jump the polar wander stops after a finite time controlled by the slowest isostatic mode

excitation of the earth s rotational axis by recent glacial discharges we study the effects of present day glacial dis charges and the growth of the antarctic ice sheet on exciting the earth s rotational axis glacial forcing could cause a maximum change in j of about one third of the observed amount for the maxwell rheology and for burgers body models with a long term lower mantle viscosity greater than about 1023p for transient rheologies the amount of excitation due to glacial melting decreases polar wander is not much excited by recent glacial melting for the various types of rheologies examined

subducted slabs and the geoid constraints on mantle rheology and flow geoid anomalies are primarily the result of the density contrasts driving mantle convection and plate motion the total geoid anomaly resulting from a given density contrast in a convecting earth is affected by the mass anomalies associated with the flow induced deformation of the upper surface and internal compositional boundaries as well as by the density contrast itself these boundary deformations and hence the total gravity field depend on the radial distribution of effective viscosity if the internal density contrasts can be estimated as is the case for subducted slabs useful constraints can be placed on the depth and on the variation of viscosity with depth of the convecting system the degree 4 9 components of the observed long wavelength geoid are highly correlated with those predicted by a density model for seismically active subducted slabs the positive sign of the correlation requires that the effective viscosity increases with depth by a factor of 30 or more the amplitude of the correlation cannot be explained by the density contrasts associated with just the seismically active parts of subducted slabs however the amplitude can be explained if the density contrasts associated with subduction extend into the lower mantle or if old lithosphere is piled up at the base of the upper mantle beneath subduction zones to a thickness in excess of 350 km over horizontal distances of thousands of kilometers mantlewide convection in a mantle that has a viscosity increasing with depth provides a simple explanation of the long wavelength geoid anomalies over subduction zones

present day secular variations in the zonal harmonics of earth s geopotential we develop a new formalism for the prediction of secular variations in the gravitational potential field of a spherically symmetric self gravitating maxwell viscoelastic planetary model subjected to an arbitrary surface load which may include a gravitationally self consistent ocean loading component the theory is applied to generate the most accurate predictions to date of the present day secular variations in the zonal harmonics of the geopotential the so called for degree arising as a consequence of the late pleistocene glacial cycles in this respect we use the very recent ice 3g reconstruction of the last late pleistocene deglaciation event tushingham and peltier 1991 a comparison of these predictions with those generated using simplified disk models of the ice sheets which have been used in all previous studies of the harmonics 2 indicates that the disk model approximation introduces unacceptably large errors at all spherical harmonic degrees except perhaps 2 predictions have also been made using a eustatic loading approximation also used in previous studies in place of a gravitationally self consistent ocean loading component and we have found that the resulting discrepancy is largest at degrees 2 8 and 10 in the case of the magnitude of the error incurred using the eustatic approximation can be as large as order 10 15 of the predicted value we have attributed this discrepancy to the present day net flux of water away from the equatorial regions arising from the remnant present day adjustment associated with the late pleistocene glacial cycles the effect represents a heretofore unrecognized contribution to the harmonics or alternatively the nontidal acceleration of earth s axial rate of rotation in terms of the latter the maximum anomaly in the length of day is approximately 1 7 s yr we also consider the sensitivity of the data to variations in the radial mantle viscosity profile by using a suite of forward calculations and an examination of frechet kernels the theory required for the computation of those kernels is described herein we find that the radial variation in sensitivity can be a strong function of the viscosity model used in the calculations for models with a uniform upper mantle viscosity um of 1021 pa s forward predictions of the harmonics exhibit a pronounced peak when a wide enough range of lower mantle viscosities lm are considered we denote the lm value at this peak as at the lowest degrees 4 frechet kernels computed for a series of increasing lm values 1021 pa s lm 1023 pa s indicate a migration of the dominant sensitivity of the data to variations in viscosity from regions below approximately 1200 km depth for to regions above this depth in the lower mantle for the sensitivity of the data to variations in the viscosity profile in the shallowest parts of the lower mantle for the case is also reflected in a set of forward calculations described herein as an example predictions made using earth models in which the viscosity above 1200 km depth is constrained to be 1021 pa s do not exhibit the multiple solutions characteristic of the um 1021 pa s calculations the same is true of earth models in which the upper mantle viscosity is weakened an order of magnitude to 1020 pa s the theory described herein is also applied to compute the signal 10 arising from the retreat of small ice sheets and glaciers described by meier 1984 and also from any potential variations in the mass of the antarctic and greenland ice sheets the present day signal due to the late pleistocene glacial cycles dominates the signal from meier s sources at all degrees except 3 in contrast the signal arising from mass variations in the antarctic and greenland ice sheets is potentially comparable to the former a comparison of observational constraints on the data with predictions of the postglacial rebound signal described in this paper in order to infer mantle rheology cannot proceed until constraints are placed on the present day mass flux of these large polar ice sheets we show that the constraints required are weakest at degrees 2 and 4 finally we outline a potentially important procedure for incorporating predictions of the signal due to the late pleistocene glacial cycles and meier s sources with an observational constraint on the datum to yield bounds on the present day net mass flux from the antarctic and greenland ice sheets a rigorous application of this procedure must wait until observational constraints on are reestablished in the literature

changes in rotation induced by pleistocene ice masses with stratified analytical earth models the rotational response of the earth to pleistocene deglaciation is studied by means of a multilayered viscoelastic earth model based on the preliminary reference earth model prem incompressible viscoelastic deformation is evaluated from a self compressed initial state the novelty of our approach stands on the application of a fully analytical normal mode theory to the response of the earth to surface loads and variations in the centrifugal potential for large numbers of viscoelastic layers as requested by prem assuming that both present day true polar wander tpw and changes in the second degree component of the geopotential are solely due to pleistocene postglacial rebound we obtain for a two layer viscosity model that the upper mantle viscosity must be lowered to about 1 5 1020 pa s with respect to the classical value of 1021 pa s this upper mantle viscosity is accompanied by an increase of the lower mantle viscosity by a factor of 25 in agreement with some recent relative sealevel rsl data analyses and convectively supported long wavelength geoid anomalies when the viscosity contrast is located at 1470 km depth tpw and require a viscosity of 1021 pa s in the upper part of the mantle above 1470 km depth with a moderate viscosity increase in the lowermost portion of the mantle this result indicates that a viscosity of 1021 pa s is appropriate for a wider portion of the mantle than the upper mantle in agreement with haskell s 1935 estimate that was not limited to the seismically inferred 670 km boundary

pleistocene deglaciation and the earth s rotation a new analysis summary this paper is concerned with an analysis of the effect of the pleistocene glacial cycle upon the earth s rotation we demonstrate that two important geophysical observables may be explained as aspects of the rotational response to surface mass loading by ice sheets these are the astronomically observed non tidal component of the acceleration of planetary rotation and the secular drift of the rotation pole relative to the surface geography which is evident in the ils pole path the former observation is shown to provide an unambiguous constraint upon the viscosity of the planetary mantle and requires a depth dependence of this parameter which is the same as that which has previously been inferred in studies of the relative sea level variations and free air gravity anomalies associated with post glacial rebound the observed secular drift of the pole cannot provide an independent estimate of the viscosity of the mantle because it depends jointly upon mantle viscosity and lithospheric thickness with the viscosity profile fixed by the rebound data the observed speed of polar wander suggests a continental lithospheric thickness which is in excess of that appropriate for old ocean basins but nevertheless in accord with independent constraints

hafting wear on quartzite tools an experimental case from the wulanmulun site inner mongolia of north china abstract usewear analysis is one of the most important and significant methods in studying the hafting wear the raw material used in this article is quartzite gathered from identified raw material resource of wulanmulun site and the wooden handle and hemp rope are used as the binding material of accomplishing the experimental study on the hafting wear on quartzite tools the low power technique was applied in observing stone specimens the research shows that the hafting wear on quartzite tools has its own regular pattern that can be well recognized by the low power technique generally the difference of major features and patterns of hafting wear occurred and distributed at areas of the lateral edges surface ridges and basal edges of the lower part on the specimens can be well distinguished the binding material binding method processing way of binding and the morphology of stone specimen themselves can be also affected factors to the hafting wear patterns the present study may contribute a partial set of reference standards in constructing hafting wear patterns on the quartzite tools and aid interpretation of features observed on archaeological assemblages on the basis of the low power technique

changes of the earth s rotation axis owing to advection of mantle density heterogeneities polar wander the secular motion of the earth s rotation axis relative to its surface has been studied for many years dynamical arguments1 3 show that polar wander can arise from the redistribution of mass in a plastic deformable earth the rate depending on both the rate of mass redistribution and the rate at which the earth s rotational bulge can readjust to the changing rotation axis here we use a viscosity structure obtained through geoid modelling4 a mantle flow field consistent with tomographic anomalies5 and time dependent lithospheric plate motions6 to calculate the advection of mantle density heterogeneities and corresponding changes in the degree two geoid during the cenozoic era we show that the rotation axis will follow closely any imposed changes of the axis of maximum non hydrostatic moment of inertia the resulting path of the rotation axis agrees well with palaeomagnetic results7 with the model predicting a current rate of polar motion that explains 40 of that observed geodetically8

a preliminary study on human behavior and lithic function at the wulanmulun site inner mongolia china the wulanmulun site located in southwestern inner mongolia china is an important paleolithic discovery in the ordos plateau in addition to the sites of salawusu and shuidonggou about 4200 stone artifacts 3400 fossils and abundant hunting evidence of hominid were uncovered in 2010 in order to explore stone tool function and human behavior at wulanmulun during the middle to late pleistocene we have selected 140 specimens excavated from locality 1 of wulanmulun in 2010 for use wear analysis the results suggest that 58 specimens retain evidence of use wear accounting for 41 4 of the observed samples many stone artifacts display use wear and several show wear from hafting the working motion was dominated by defleshing and slicing and the main contact materials were animal substances animal processing might have been one of the main working tasks at locality 1 of wulanmulun as numerous animal bone fragments with obvious cut marks and burnt bones were also found in situ