depositional and sea level history from mis 6 termination ii to mis 3 on the southern continental shelf of south africa abstract pleistocene shoreline deposits comprised of calcified shallow marine palaeobeach and aeolian palaeodune facies found along mid latitude coastlines can be useful indicators of past sea levels here we describe a succession of such deposits that are presently exposed both above subaerial and below submerged mean sea level along the southern cape coast of south africa 18 km east of the town of mossel bay the submerged units provide a window on late pleistocene coastal processes as palaeoshoreline deposits in this study extend to water depths of up to 55 m on the mid shelf five sedimentary facies were identified in the strata and were compared to modern depositional environments of the local littoral zone which include aeolian dune upper shoreface foreshore intertidal swash and back barrier settings twenty two geological units were observed and mapped some of these units were directly dated with optically stimulated luminescence osl dating osl ages were obtained for ten samples from the subaerial and twelve samples from the submerged deposits those geological units not directly dated were interpreted based on sedimentology and field stratigraphic relationships to dated units the stratigraphy and chronology of the succession indicates a record of initial deposition during termination ii t ii meltwater events preceding and leading to marine isotope stage mis 5e indicators for multiple sea level fluctuations between mis 5d and mis 4 and sediment deposition at the end of mis 4 and start of mis 3 are also found both regressive and transgressive depositional cycles are well preserved in the succession we propose that palaeodune and palaeobeach deposits along the south coast of south africa have no clear preference for deposition during sea level transgressions or regressions sediment deposition more closely mirrors the rate of sea level change with deposition and preservation either during times of rapid sea level movement or oscillation around still stand events periods of relatively slow average rise or fall of sea level are represented by erosional planation surfaces in this record

luminescence dating at diepkloof rock shelter new dates from single grain quartz diepkloof rock shelter in south africa s western cape has been the subject of two different luminescence dating projects in recent years jacobs et al 2008 tribolo et al 2013 with somewhat divergent results this paper presents dating analysis of three additional samples from diepkloof as well as one sample each from kathu pan 6 and hollow rock shelter also in south africa these samples were collected in 1995 prior to the other two projects analysis of single grain quartz shows that the samples are near saturation conventional rejection criteria when applied to dose recovery data result in an underestimation of dose for high administered doses applying the fast ratio durcan and duller 2011 duller 2012 as a rejection criterion removes this underestimation and preferentially rejects grains from the samples with low equivalent dose values this makes the ages older than they would have been without this criterion age results are older than those presented by jacobs et al 2008 and slightly older or equivalent to those provided by tribolo et al 2013

3 d numerical simulations of earthquake ground motion in sedimentary basins testing accuracy through stringent models summary differences between 3 d numerical predictions of earthquake ground motion in the mygdonian basin near thessaloniki greece led us to define four canonical stringent models derived from the complex realistic 3 d model of the mygdonian basin sediments atop an elastic bedrock are modelled in the 1d sharp and 1d smooth models using three homogeneous layers and smooth velocity distribution respectively the 2d sharp and 2d smooth models are extensions of the 1 d models to an asymmetric sedimentary valley in all cases 3 d wavefields include strongly dispersive surface waves in the sediments we compared simulations by the fourier pseudo spectral method fpsm the legendre spectral element method sem and two formulations of the finite difference method fdm s and fdm c up to 4hz the accuracy of individual solutions and level of agreement between solutions vary with type of seismic waves and depend on the smoothness of the velocity model the level of accuracy is high for the body waves in all solutions however it strongly depends on the discrete representation of the material interfaces at which material parameters change discontinuously for the surface waves in the sharp models an improper discrete representation of the interfaces can cause inaccurate numerical modelling of surface waves for all the numerical methods considered except sem with mesh of elements following the interfaces a proper implementation of interfaces requires definition of an effective medium consistent with the interface boundary conditions an orthorhombic effective medium is shown to significantly improve accuracy and preserve the computational efficiency of modelling the conclusions drawn from the analysis of the results of the canonical cases greatly help to explain differences between numerical predictions of ground motion in realistic models of the mygdonian basin we recommend that any numerical method and code that is intended for numerical prediction of earthquake ground motion should be verified through stringent models that would make it possible to test the most important aspects of accuracy

the chronological sedimentary and environmental context for the archaeological deposits at blombos cave south africa abstract the site of blombos cave bbc is well known for archaeological remains that have advanced our understanding of the development of modern human behaviour during the middle stone age msa occupation of the cave occurred against a backdrop of landscape scale environmental and sedimentary processes that provide the broader context for finer scale interpretations of the site formation history and archaeological patterns detected in the cave deposits aeolian and palaeosol sequences are abundant in the vicinity of bbc and these provide a partial view of the past landscapes available to the inhabitants of the cave an important extension to the palaeo landscape around bbc currently lies submerged on the agulhas bank as sea levels were lower than at present for the entire period of human occupation of bbc in this paper we revisit the optically stimulated luminescence osl chronology for the full sequence of sediment deposition inside bbc increasing the number of dated samples to a total of 40 and revising the period of msa occupation to between 97 7 7 6 and 71 0 5 7 ka uncertainties at 95 4 probability we describe the geological successions at four main areas around bbc estimate the time of sediment deposition using osl and describe and interpret three seismic profiles on the agulhas bank offshore of bbc by correlating these onshore and offshore geological sequences with the sedimentary deposits inside bbc we place the archaeological record within a landscape scale chrono stratigraphic framework to examine how environmental changes may have regulated the presence or absence of humans in the cave and surrounding terrain between about 100 and 70 ka

ambiguities in human and elephant interactions stories of bones sand and water from castel di guido italy geoarchaeological and taphonomical studies have been carried out on the sequence and on the faunal remains of castel di guido central italy a middle pleistocene site with acheulean industry and faunas including elephas palaeoloxodon antiquus bos primigenius equus ferus and other taxa investigation focused on remains accumulated on the bottom of a depressed area probably an ephemeral stream channel sometimes acting as a seep the assemblage resulted prevalently from human activity as shown by the selection of the faunas by the thorough fracturing of the bones and by the occurrence of abundant chipped stone industry and bone bifaces it is still a matter of debate whether the animals were hunted or scavenged the present day distribution of the remains does not represent exactly their original configuration as in most sites of this type and age more likely the objects are partly in their original position and partly reworked and lie within a complex palimpsest of several phases of fluvial transport and human activity with the addition of external inputs of reworked bones and artefacts

occupational intensity and environmental changes during the howiesons poort at klipdrift shelter southern cape south africa abstract the howiesons poort characterised by sophisticated lithic technologies and evidence of innovative behaviours was a significant cultural phase in southern africa during marine isotope stage 4 it also coincided with substantial palaeoenvironmental and possible demographic changes in the southern cape of south africa especially with regard to the shifting palaeo coastline off the agulhas bank the newly excavated klipdrift shelter in the southern cape presents a rare opportunity to compare faunal lithic and palaeoenvironmental evidence from a single howiesons poort site along the present day southern coast of south africa here we use faunal data from klipdrift shelter to explore the relationship between occupational intensity subsistence behaviour and environment in the southern cape during the howiesons poort period our results suggest a shift from a mixed terrain browse dominated environment during the earlier howiesons poort to open grasslands in the mid later howiesons poort this environmental shift corresponds to potential changes in occupational intensity or frequency throughout the sequence with evidence of increased occupations associated with grassier environments aspects of the cultural sequence for example raw material procurement strategies may be associated with shifting environmental conditions the faunal evidence suggests links between occupation environment and prey selection at klipdrift this raises interesting questions about the interplay between population density and the environment of the southern cape and its influence on subsistence behaviour during marine isotope stage 4

wave propagation in heterogeneous porous media a velocity stress finite difference method a particle velocity stress finite difference method is developed for the simulation of wave propagation in 2 d heterogeneous poroelastic media instead of the prevailing second order differential equations we consider a first order hyperbolic system that is equivalent to biot s equations the vector of unknowns in this system consists of the solid and fluid particle velocity components the solid stress components and the fluid pressure a maccormack finite difference scheme that is fourth order accurate in space and second order accurate in time forms the basis of the numerical solutions for biot s hyperbolic system an original analytic solution for a p wave line source in a uniform poroelastic medium is derived for the purposes of source implementation and algorithm testing in simulations with a two layer model additional slow compressional incident transmitted and reflected phases are recorded when the damping coefficient is small this slow compressional wave is highly attenuated in porous media saturated by a viscous fluid from the simulation we also verified that the attenuation mechanism introduced in biot s theory is of secondary importance for fast compressional and rotational waves the existence of seismically observable differences caused by the presence of pores has been examined through synthetic experiments that indicate that amplitude variation with offset may be observed on receivers and could be diagnostic of the matrix and fluid parameters this method was applied in simulating seismic wave propagation over an expanded steam heated zone in cold lake alberta in an area of enhanced oil recovery eor processing the results indicate that a seismic surface survey can be used to monitor thermal fronts

middle and late pleistocene paleoscape modeling along the southern coast of south africa abstract changing climates environment and sea levels during the middle and late pleistocene must have had significant impacts on early modern humans and their behavior however many important archaeological sites occur along the current coastline of south africa where the gradual slope of the offshore agulhas bank meant that small changes to sea level height potentially caused significant shifts in coastline position the geographic context of these currently coastal sites would have been transformed by sea level shifts from coastal to near coastal to fully terrestrial to understand human adaptations as reflected in the archaeological deposits of these now coastal sites we need to accurately model coastline position through time here we introduce a paleoscape model as a conceptual tool to ground the records for human behavioral evolution within a dynamic model of paleoenvironmental changes using integrated bathymetric datasets gis and a relative sea level curve we estimate the position of the coastline at 1 5 ka increments over the last 420 000 years we compare these model predictions to strontium isotope ratios from speleothems as an independent test and then compare the coastline predictions to evidence for shellfish exploitation through time both tests suggest our model is relatively robust we then widen our paleoscape model to most of the cape region and compare the predictions of this broadened model to evidence from blombos cave

greenland ice sheet surface properties and ice dynamics from ers 1 sar imagery c band synthetic aperture radar sar imagery from the european space agency s ers 1 satellite reveals the basic zonation of the surface of the greenland ice sheet the zones have backscatter signatures related to the structure of the snowpack which varies with the balance of accumulation and melt at various elevations the boundaries of zones can be accurately located with the use of this high resolution imagery the images also reveal a large flow feature in northeast greenland that is similar to ice streams in antarctica and may play a major role in the discharge of ice from the ice sheet

strontium isotope investigation of ungulate movement patterns on the pleistocene paleo agulhas plain of the greater cape floristic region south africa abstract middle stone age sites located within the greater cape floristic region on the south african southern coast have material culture with early evidence for key modern human behaviors such as projectile weaponry large animal hunting and symbolic behavior in order to interpret how and why these changes evolved it is necessary to understand their ecological context as it has direct relevance to foraging behavior during periods of lowered sea level a largely flat and vast expanse of land existed south of the modern coastline but it is now submerged by higher sea levels this exposed area the paleo agulhas plain likely created an ecological context unlike anything in the region today as evidenced by fossil assemblages dominated by migratory ungulates one hypothesis is that the paleo agulhas plain supported a migration ecosystem of large grazers driven by summer rainfall producing palatable forage during summer in the east and winter rainfall producing palatable forage during winter in the west alternatively ungulates may have been moving from the coastal plain in the south to the interior north of the cape fold mountains as observed for elephants in historic times in this study we assess ungulate movement patterns with inter and intra tooth enamel samples for strontium isotopes in fossil fauna from pinnacle point sites pp13b and pp30 to accomplish our goals we created a bioavailable 87sr 86sr isoscape for the region by collecting plants at 171 sampling sites and developing a geospatial model the strontium isotope results indicate that ungulates spent most of their time on the paleo agulhas plain and avoided dissected plain foothill and mountain habitats located more than about 15 km north of the modern coastline the results clearly exclude a north south coastal interior movement or migration pattern and cannot falsify the east west movements hypothesized in the south coast migration ecosystem hypothesis

settlement patterns during the earlier and middle stone age around langebaan lagoon western cape south africa the landscape around langebaan lagoon in the western cape of south africa contains a rich archive of middle and late pleistocene hominin behavior stone age localities of all ages are abundant and present a valuable perspective on the region s settlement history a complex pattern of land use is evident starting with an analysis of the earlier stone age esa collections from anyskop combined with a review of data from elandsfontein and duinefontein these late acheulian assemblages demonstrate an emphasis on handaxe production the exploitation of medium and large game and use of non local raw materials while seasonal pans provided water for animals and humans at these esa localities anyskop is distinctive because of its hilltop setting lacking water and direct access to game middle stone age msa assemblages from geelbek and anyskop combined with a review of data from hoedjiespunt sea harvest and ysterfontein provide further evidence for a regional settlement system that also incorporated non local raw materials into the lithic provisioning strategy some msa lithic technologies in the western cape were aimed at the production of bifacial points and blades as well as backed elements subsistence strategies expanded to encompass the utilization of both terrestrial and marine resources although symbolic artifacts are rare from these sites worked ochre is present at hoedjiespunt these behavioral patterns suggest that the middle and late pleistocene hominins who left these esa and msa materials behind were adept masters of their environment with adaptations well suited to the west coast landscape

geoarchaeological investigation of occupation deposits in blombos cave in south africa indicate changes in site use and settlement dynamics in the southern cape during mis 5b 4

trampling in coastal sites an experimental study on the effects of shell on bone in coastal sediment abstract faunal remains are often recovered from shelly deposits in coastal sites but little is known about the trampling effects of shell on bone here trampling experiments were conducted to investigate these effects and to describe the types of surface modification that could occur on bone in coastal sediment the results suggest that bone is significantly more likely to exhibit surface modification if trampled in shelly rather than sandy sediment burnt bone is less likely to display trampling modification this is probably because prior to trampling burning exfoliates the cortex making the observation of markings on bone problematic pitting trampling lines and sheen were found to be the most prevalent form of surface modification pitting is a particularly over looked criterion and its presence on archaeological bone suggests that the effects of trampling should be considered in zooarchaeological analyses the pervasiveness of sheen and trampling lines on the experimental bone makes it possible that some incidence of trampling could be mistaken for use wear or intentional polish however the vast majority of trampled bone exhibits sheen which does not resemble anthropogenic specimens and trampling is unlikely to smooth bone fragment edges this experiment demonstrates that modification caused by trampling can generally be differentiated from butchery markings the high percentage of modified trampled bone in the shelly deposits suggests that some shell marks may be mistaken for cut marks if recovered in an archaeological context

snow crystal growth with varying surface temperatures and radiation penetration the temperature field is derived for a sinusoidally varying surface temperature with varying solar radiation penetration the growth rates of snow crystals are calculated to explain the rapidly growing layers of faceted crystals i e depth hoar that form just below the surface at high altitudes and in polar snow the solutions also show that a layer of wet snow can exist just below the surface even on days when the surface temperature remains sub freezing

geoarchaeological investigations at diepkloof rock shelter western cape south africa abstract the sedimentary sequence at diepkloof rock shelter formed through a complex interaction of depositional and post depositional processes and was variously influenced by biogenic geogenic and anthropogenic agents here we present the results of a micromorphological study of the sediments at diepkloof focusing in particular on the numerous anthropogenic inputs and modifications recorded within the sequence by applying the microfacies concept we were able to identify hearth burning and maintenance bedding construction and burning and surface modification by trampling as major processes that contributed to the formation of the site the human activities recorded within the sediments show a marked change throughout the sequence implying a shift in the use of the site over time the present study also provides a context for evaluating other classes of artifacts and data collected from the site

early use of pressure flaking on lithic artifacts at blombos cave south africa pressure flaking has been considered to be an upper paleolithic innovation dating to 20 000 years ago 20 ka replication experiments show that pressure flaking best explains the morphology of lithic artifacts recovered from the 75 ka middle stone age levels at blombos cave south africa the technique was used during the final shaping of still bay bifacial points made on heat treated silcrete application of this innovative technique allowed for a high degree of control during the detachment of individual flakes resulting in thinner narrower and sharper tips on bifacial points this technology may have been first invented and used sporadically in africa before its later widespread adoption

an improved single grain osl chronology for the sedimentary deposits from diepkloof rockshelter western cape south africa the single grain optically stimulated luminescence osl chronology for the sedimentary deposit at diepkloof rockshelter reported by jacobs et al 2008c has recently been critiqued and several reasons proposed for why the osl ages for the intermediate and early howieson s poort hp and still bay sb techno complexes might be inaccurate tribolo et al 2013 presented a series of osl and thermoluminescence tl ages that were in agreement with each other but for some part of the sequence at least were much older than the osl chronology of jacobs et al 2008c in this paper we have tested the criticisms of tribolo et al 2013 and colleagues related to both the equivalent dose de estimates and the beta dose rates by performing a series of targeted experiments combined with updates and re assessments of our error calculations we show that the de estimates are stable over a range of alternative measurement conditions and also over time we also demonstrate the reproducibility of our measurement procedures for the beta dose rates and their accuracy tested against a range of independently obtained estimates we show that for the stratigraphic units sus where there are major discrepancies in age between jacobs et al 2008c and tribolo et al 2013 notably the intermediate hp and early hp and for which both studies had single grain osl ages the estimation of potassium k in the sediment surrounding the dated grains is critical we provide new and updated de and dose rate estimates and final ages which we compare with our previous age estimates and those of tribolo et al 2013 the differences in the size of the errors associated with the ages reported in the two independent studies are also addressed we can show that our ages are robust and consistent with the original chronology but we cannot satisfactorily explain why the tl and osl ages provided by tribolo et al 2013 might be wrong so the dating conundrum at diepkloof rockshelter remains as a result we caution against the development of hp and sb age models based on only one of the chronologies for this site at this stage extrapolation of the tribolo et al 2013 chronology to a re interpretation of the southern african msa would appear to be premature especially as the ages do not differ systematically between the two studies and as differences between tl and osl ages are not an issue at other sites in southern africa where both dating methods have been applied further work is needed to resolve the question of the diepkloof chronology

heat induced alteration of glauconitic minerals in the middle stone age levels of blombos cave south africa implications for evaluating site structure and burning events abstract in this paper we conduct geochemical and colourimetric measurements of glauconite grains in micromorphological thin sections from the middle stone age site of blombos cave south africa to investigate the formation internal structure and reworking of heat exposed cave deposits that are related to prehistoric burning events controlled heating experiments were first carried out on glauconite rich loose sediments and block samples both of which were collected from the blombos cave bedrock the control samples were then subjected to fourier transform infrared spectrometry ftir microscopic fourier transform infrared spectrometry micro ftir and petrographic colourimetric analyses the control experiment shows that glauconitic minerals undergo a gradual and systematic colour change when temperatures reach higher than c 300 400 c primarily due to dehydration and iron oxidation they also undergo clear structural changes when temperatures reach higher than c 550 c due to dehydroxylation and mineral transformation by assessing the nature and degree of heat induced optical and molecular alteration in glauconitic minerals we demonstrate how glauconite grains in thin sections can be classified by the temperature to which they were exposed 20 400 c 400 c 600 c and 800 c to assess the archaeological relevance of our controlled heating experiment we applied this glauconite classification scheme to 200 grains found in three micromorphological thin sections of a middle stone age msa combustion feature these grains were individually geo referenced within the local coordinate system of blombos cave through a thin section based gis mapping procedure with improved spatial control we were able to study both the general distribution of non altered and heat altered glauconite grains in their original sedimentary context as well as to calculate heat distribution models that cover the entire sampled section this combined geo chemical optical and spatio contextual approach provides insights into more elusive aspects of msa site structure and burning events such as heat intensity burning frequency temperature distribution internal hearth structure and post depositional reworking the workflow we propose may easily be implemented and adapted to other archaeological contexts and to analogous sedimentary materials that show comparable heat induced alteration patterns

bat guano and preservation of archaeological remains in cave sites the formation of authigenic minerals in cave sediments can be used to reconstruct the paleochemical conditions that prevailed in the past and in this way to assess the completeness of the archaeological record previous studies indicated that the major driving mechanisms for chemical diagenesis in prehistoric caves that result in the formation of authigenic minerals are the degradation of bat guano and the local hydrology we therefore investigated contemporary bat guano deposits in caves and the sediments directly below such deposits the emerging patterns show that the formation of authigenic minerals occurs under acidic conditions within tens of years the availability of phosphate al k and fe increases with increasing organic matter degradation while the availability of nitrogen and sulfur decreases insectivorous bat guano contains larger amounts of phosphate and is more acidic than fruit bat guano in the first stages of diagenesis micro chemical environments form within the degrading bat guano that result in the formation of a wide variety of authigenic minerals during advanced stages of diagenesis steady state conditions are achieved resulting in authigenic mineral assemblages being dominated by one mineral type at the same locale this is reminiscent of known distributions of authigenic minerals in prehistoric cave sediments under the acidic conditions produced by degrading bat guano deposits calcareous artifacts and bones are not expected to persist for long periods of time unless there is a lot of calcite in the sediments that could buffer the sediment water ph guano itself is not likely to be preserved periods of cave abandonment can be inferred from the presence of authigenic minerals in the sediments as it is during these times that bats mainly occupy the cave the occurrence of certain authigenic minerals in open air sites may serve as evidence for areas rich in organic matter containing phosphate i e animal enclosures latrines sewers trash pits and or bones as the degradation process is rapid the use of authigenic minerals to identify these loci is relevant to almost all archaeological as well as historical sites

size matters preliminary results from an experimental approach to interpret middle stone age hearths abstract this paper reports on ten fire experiments and their significance for interpreting hearths from the middle stone age site sibudu kwazulu natal south africa the experiments were conducted on four different substrata and four wood taxa were used in the experiments four of the experiments consisted of a single fire while the other experiments consisted of multiple fires on top of each other the experimental fires produced hearth areas of 962 1 1661 9 cm and hearth depths of 3 12 cm hearth size and depth do not correlate hearth area seems to correlate with the fuel load used in a hearth and it is argued that this can be used in interpretations of fire use at an archaeological site nine hearths from the same layer at sibudu are used as examples and it is argued that variation in hearth area indicates variation in hearth use some hearths at sibudu were possibly only used once whereas others represent long term use and or repeated reloading of the same hearth

blombos cave southern cape south africa preliminary report on the 1992 1999 excavations of the middle stone age levels the later and middle stone age levels at blombos cave bbc were excavated over four field seasons between 1992 and 1999 here we report on the results from the middle stone age msa levels the taphonomy and depositional history of the msa levels is complex due to faulting folding and spalling careful observations during excavation have assisted in understanding some of these taphonomic and site formation processes microstratigraphic analysis currently in progress will add to this information the uppermost msa level the still bay phase contains high densities of bifacial points the fossile directeur of the still bay industry placing the still bay within the msa culture sequence has been problematic in the past because still bay assemblages are rarely found in situ and previous excavations were inadequately recorded however with the regional data discussed in the text the still bay can be securely placed before the howiesons poort dated at 65 70 ka flaked stone makes up the greatest proportion of all artefacts with the highest incidence of retouch and use of fine grained non local materials found in the still bay levels the ochre assemblage is remarkable for the mass of material compared to other msa sites finds uncommon in an msa context are two pieces of ochre from the still bay phase engraved with a geometric design a fragment of deliberately engraved bone also 28 shaped and polished bone tools recovered mainly from a phase just below the still bay blombos cave is the first site where well preserved faunal remains have been recovered in association with the still bay allowing for unique insights into human subsistence behaviour and palaeoenvironmental reconstruction large fish bones marine shells seals and dolphins attest to extensive exploitation of aquatic resources and a wide range of terrestrial animals were hunted and gathered the few human teeth recovered are heavily worn and damaged thus the issue of morphological modernity cannot be addressed the bbc findings are a useful adjunct to findings from other msa coastal sites in the southern cape especially klasies river kr and die kelders cave 1 dk1 uniquely bbc provides insights into human behaviour during a phase of the msa never before studied in detail

pleistocene sea level fluctuations and human evolution on the southern coastal plain of south africa abstract humans evolved in africa but where and how remain unclear here it is proposed that the southern coastal plain scp of south africa may have served as a geographical point of origin through periodic expansion and contraction isolation in response to glacial interglacial changes in sea level and climate during pleistocene interglacial highstands when sea level was above 75 m human populations were isolated for periods of 360 3400 25 yr generations on the scp by the rugged mountains of the cape fold belt climate and vegetation barriers the scp expands five fold as sea level falls from 75 to 120 m during glacial maxima to form a continuous unobstructed coastal plain accessible to the interior an expanded and wet glacial scp may have served as a refuge to humans and large migratory herds and resulted in the mixing of previously isolated groups the expansive glacial scp habitat abruptly contracts by as much as one third in 300 yr during the rapid rise in sea level associated with glacial terminations rapid flooding may have increased population density and competition on the scp to select for humans who expanded their diet to include marine resources or hunted large animals successful adaptations developed on an isolated scp are predicted to widely disperse during glacial terminations when the scp rapidly contracts or during the initial opening of the scp in the transition to glacial maxima the hypothesis that periodic expansion and contraction of the scp as well as the coastal plain of north africa contributed to the stepwise origin of our species over the last 800 thousand years kyr is evaluated by comparing the archeological dna and sea level records these records generally support the hypothesis but more complete and well dated records are required to resolve the extent to which sea level fluctuations influenced the complex history of human evolution

variability in the middle stone age lithic sequence 115 000 60 000 years ago at klasies river south africa abstract stratified samples of artefacts from the late pleistocene deposit at the klasies river main site covering some 60 000 years have been studied variability in the artefact sequence has been documented in the technologies of artefact production in addition to conventional typological analysis particular emphasis has been given to the recognition of the reduction sequences used in producing the pre formed blanks that are a feature of the middle stone age the results show that the variability is due to changes between the dominant blade and or point technological conventions traditions through time technological study supports and gives meaning to the recognition of distinct sub stages msa i klasies river msa ii mossel bay howiesons poort and a post howiesons poort at main site these sub stages are more than convenient site specific organizational entities they delineate separate technological conventions that may have relevance on a sub continental scale

finite difference modeling of wave propagation and diffusion in poroelastic media numerical modeling of seismic waves in heterogeneous porous reservoir rocks is an important tool for interpreting seismic surveys in reservoir engineering various theoretical studies derive effective elastic moduli and seismic attributes from complex rock properties involving patchy saturation and fractured media to confirm and further develop rock physics theories for reservoir rocks accurate numerical modeling tools are required our 2d velocity stress finite difference scheme simulates waves within poroelastic media as described by biot s theory the scheme is second order in time contains high order spatial derivative operators and is parallelized using the domain decomposition technique a series of numerical experiments that are compared to exact analytical solutions allow us to assess the stability conditions and dispersion relations of the explicit poroelastic finite differ ence method the focus of the experiments is to model wave induced flow accurately in the vicinity of mesoscopic hete

osl and tl dating of the middle stone age sequence at diepkloof rock shelter south africa a clarification diepkloof rock shelter offers an exceptional opportunity to study the onset and evolution of both still bay sb and howiesons poort hp techno complexes however previous age estimates based on luminescence dating of burnt quartzites tribolo et al 2009 and of sediments jacobs et al 2008 were not in agreement here we present new luminescence ages for 17 rock samples equivalent dose estimated with a sar itl protocol instead of classical maad tl as well as for 5 sediment samples equivalent dose estimated with sar single grain osl protocol and an update of the 22 previous age estimates for burnt lithics modified calibration and beta dose estimates while a good agreement between the rock and sediment ages is obtained these estimates are still significantly older than those reported by jacobs et al 2008 after our own analyses of the sediment from diepkloof it is suspected that these authors did not correctly chose the parameters for the equivalent dose determination leading to an underestimate of the equivalent doses and thus of the ages from bottom to top the mean ages are 100 10 ka for stratigraphic unit su noel and 107 11 ka for su mark uncharacterized lower msa 100 10 ka for su lynn leo pre sb type lynn 109 10 ka for sus kim larry sb 105 10 ka for sus kerry kate and 109 10 ka for su jess early hp 89 8 ka for su jude msa type jack 77 8 ka for su john 85 9 ka for su fox 83 8 ka for su fred and 65 8 ka for su ob5 intermediate hp 52 5 ka for sus ob2 4 late hp this chronology together with the technological analyses greatly modifies the current chrono cultural model regarding the sb and the hp and has important archaeological implications indeed sb and hp no longer appear as short lived techno complexes with synchronous appearances for each and restricted to oxygen isotopic stage ois 4 across south africa as suggested by jacobs et al 2008 2012 rather the sequence of diepkloof supports a long chronology model with an early appearance of both sb and hp in the first half of ois 5 and a long duration of the hp into ois 3 these new dates imply that different technological traditions coexisted during ois 5 and 4 in southern africa and that sb and hp can no longer be considered as horizon markers

earthquake ground motion in the mygdonian basin greece the e2vp verification and validation of 3d numerical simulation up to 4 hz n a low seismicity context the use of numerical simulations becomes essential due to the lack of representative earthquakes for empirical approaches the goals of the euroseistest verification and validation project e2vp are to provide 1 a quantitative analysis of accuracy of the current most advanced numerical methods applied to realistic 3d models of sedimentary basins verification and 2 a quantitative comparison of the recorded ground motions with their numerical predictions validation the target is the euroseistest site located within the mygdonian basin greece the site is instrumented with surface and borehole accelerometers and a 3d model of the medium is available the simulations are performed up to 4 hz beyond the 0 7 hz fundamental frequency thus covering a frequency range at which ground motion undergoes significant amplification the discrete representation of material heterogeneities the attenuation model the approximation of the free surface and nonreflecting boundaries are identified as the main sources of differences among the numerical predictions the predictions well reproduce some but not all features of the actual site effect the differences between real and predicted ground motions have multiple origins the accuracy of source parameters location hypocentral depth and focal mechanism the uncertainties in the description of the geological medium damping internal sediment layering structure and shape of the sediment basement interface overall the agreement reached among synthetics up to 4 hz despite the complexity of the basin model with code to code differences much smaller than predictions to observations differences makes it possible to include the numerical simulations in site specific analysis in the 3d linear case and low to intermediate frequency range

microstratigraphy of the magdalenian sequence at cendres cave teulada moraira alicante spain formation and diagenesis abstract this microstratigraphic study of the magdalenian sequence in the cendres cave teulada moraira alicante spain shows the detailed evolutionary history of the deposit revealing a wide variety of pedosedimentary formation and diagenesis biogenic and anthropic processes the sequence begins with cendres xii culturally attributed to the early and middle magdalenian with high probability 95 dating placing it between 19 270 and 16 530 cal bp with some chronological hiatus it was formed from biogenic sedimentation associated with bat guano mainly of an insectivorous type and from anthropic sedimentation related to occupation floors made up of highly complex plant beds with traces of combustion one of the predominant plant tissue residues is woody angiosperm leaves or stalks detrital deposition formed by diffuse runoff increases towards the top of the level it belongs palaeoclimatically to the greenland stadial 2b gs 2b and to the first temperate pulsations of gs 2a between this horizon and the upper magdalenian there is an erosive contact there follow various levels attributed to the upper magdalenian cendres xi dated to between 16 690 and 15 640 cal bp this shows an abrupt change with respect to the previous level and results from the cryoclastic processes of the walls and solifluction processes it would coincide with the upper part of gs 2a with cendres x the detrital sedimentation is not very representative and organophosphatic crusts of cryptocrystalline apatite appear corresponding to accumulations of bird guano at a time when there was little presence of anthropic occupation the upper magdalenian sequence ends with cendres ix which in some sectors of the site presents an erosive contact with the previous level anthropic activity reappears and is dated to the interval between 15 210 and 14 240 cal bp its deposition is due to gelifluction processes in a cold medium with an increase in humidity it can be allocated to final episodes of gs 2a in transition to greenland interstadial 1 gi 1 at the end of this episode there is a phase of stabilization that can be seen from the biological activity connecting with the horizons of the early neolithic

an improved osl chronology for the still bay layers at blombos cave south africa further tests of single grain dating procedures and a re evaluation of the timing of the still bay industry across southern africa this paper presents a series of new single grain optically stimulated luminescence osl ages for the still bay at blombos cave south africa and compares them to previously published osl thermoluminescence tl and electron spin resonance esr ages for this site details are provided about the measurement and analytical procedures including a discussion of the characteristics of the osl signals of individual quartz grains this forms the basis for further investigations into the sensitivity of the equivalent dose de estimates to a range of different analytical approaches including changes in the size of the test dose the choice of signal integration interval the subtraction of an appropriate background and isolation of the most light sensitive fast component of quartz osl we also report the results of an inter operator test of de determination using seven new samples from blombos cave and demonstrate the reproducibility of results obtained for two samples that had been dated previously at another laboratory and were measured and analysed again in this study together these tests validate the robustness of the blombos cave single grain osl age estimates to a variety of alternative osl dating procedures we have incorporated for the first time these ages for blombos cave into a data set of all single grain osl ages for still bay and howieson s poort sites across southern africa and have used a statistical model to re evaluate the timing and duration of the still bay industry we calculate the most plausible start and end dates of the still bay as 72 2 ka and 71 3 ka respectively amounting to a duration of 0 9 ka and estimate with conventional 95 confidence that this industry began no earlier than 75 5 ka ended no later than 67 8 ka and lasted no longer than 6 6 ka

numerical simulation of seismic responses of poroelastic reservoirs using biot theory biot theory prosvides a framework for computing the seismic response of fluid saturated reservoirs numerical implementation by 2 d finite differences allows investigation of the effects of spatial variations in porosity permeability and fluid viscosity on seismic displacements of the solid frame and of the fluids oil gas and or water in the reservoir the porosity primarily influences wave velocities the viscosity to permeability ratio primarily influences amplitudes and attenuation synthetic crosswell vsp and surface survey seismograms for representative reservoir models contain primary and converted reflections from fluid as well as lithologic contacts and they illustrate the distribution of information available for describing a reservoir

the still bay points of blombos cave south africa we present the results of a technological and morphometric analysis of all the still bay points n 371 recovered from the 1993 to 2004 excavations at blombos cave we have been able to reconstruct the manufacturing sequence of the bifacial points from initial shaping by direct internal percussion to finished morphology by direct marginal percussion identifications of impact fractures and manufacturing breaks are based on comparisons with experimental and archaeological bifacial points of verified function i e paleoindian points from bison kill sites replicates of solutrean points mounted as spear heads or arrowheads and shot into adult cattle and experimental replication on local raw materials our analysis shows that a only a minority of the points are finished forms and that a large number of pieces are production failures a situation known at bifacial point production sites of later ages b morphometric and impact scar analyses should take into account this process and distinguish finished points from preforms and unfinished points c there were at least three different kinds of raw material sources and that there is a marked increase in the frequencies of silcrete with respect to the m2 and m3 phases at blombos d three kinds of evidence prove that some of the points were hafted axially and used as spear tips e production of bifacial points was a primary activity at the site but the hypothesis of intergroup exchange of still bay points cannot be sustained on the basis of present evidence and f the still bay phase appears to initiate a trend to relatively rapid changes in specialized hunting weaponry and that this innovation is congruent with other innovations such as bone tools shell beads and engraved ochre of the m1 and m2 phases at blombos

discrimination of glacier facies using multi temporal sar data glacier facies from the greenland ice sheet and the wrangell st elias mountains alaska are analyzed using multi temporal synthetic aperture radar sar data from the european space agency ers 1 satellite distinct zones and facies are visible in multi temporal sar data including the dry snow facies the combined percolation and wet snow facies the ice facies transient melt areas and moraine in greenland and south central alaska very similar multi temporal signatures are evident for the same facies although these facies are found at lower altitude in west greenland where the equilibrium line appears to be found at sea level at 71 30 n during the year analyzed 1992 93 probably because of the cooling effect of the eruption of mount pinatubo in greenland both the percolation and dry snow facies are excellent distributed targets for sensor calibration with backscatter coefficients stable to within 0 2 db however the percolation facies near the top of mount wrangell are more complex and less easily delineated than in greenland and at high altitude the glacier facies have a multi temporal signature which depends sensitively on slope orientation