thermoluminescence dating of a stillbay howiesons poort sequence at diepkloof rock shelter western cape south africa new excavations have been undertaken at diepkloof rock shelter drs south africa since 1999 it is one of the very few sites where howiesons poort and stillbay assemblages can be collected from the same archaeological sequence these middle stone age techno complexes are particularly interesting for their af nities with the much younger later stone age facies and their association with evidence for symbolic behaviour establishing their chronology is therefore particularly important for the understanding of the apparition and the evolution of the so called modern behaviours data already available suggest ages ranging from 55 to 80 ka for the howiesons poort and from 70 to 80 ka for the stillbay techno complexes in several south african sites the thermoluminescence dating undertaken at drs on 22 stone samples originating from the entire stratigraphic record indicates intervals starting 10 50 ka earlier for these techno complexes in this site possible caveats in the dating process are examined but to the best of our current knowledge must be rejected

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

three dimensional distribution of minerals in the sediments of hayonim cave israel diagenetic processes and archaeological implications the mineral components of the sediments that accumulate in an archaeological site constitute a potentially rich source of information on the diagenesis and in turn the archaeology of the site this detailed three dimensional study of the mineral assemblages in mainly the mousterian sediments of hayonim cave incorporates more than 2100 infrared analyses performed on site during the excavation as well as diverse analyses in the laboratory three major mineral assemblages are identified the calcite dahllite cd assemblage the assemblage comprising mainly montgomeryite leucophosphite and siliceous aggregates lmvs and a highly altered sediment in which the clays have broken down and silica was released the boundaries between these assemblages were mapped in detail the overall picture is one of extreme heterogeneity with sharp variations occurring over distances of a few centimetres the relation between the cd and lmvs assemblages shows that it is a product of post depositional diagenesis whereas the altered clay assemblage formed beneath an erosional unconformity the cd and lmvs assemblages were derived primarily from an accumulation several metres thick of ash deposits produced by humans ash is thus shown to be a major component of the sediments of this cave the distribution of the cd assemblage reflects to a large extent the locations of two active springs seepages in the cave the distribution of the cd assemblage also faithfully maps the distribution of bones in the cave showing that their distribution is a function of preservational conditions and not human activities stineret al 2001 the conditions that produced the erosional unconformity also resulted in severe alteration of the clays and other mineral components of these sediments the erosion process and the fact that the thickness of this altered zone decreases towards the centre of the cave indicates that the diagenetic driving force was probably climatic the three dimensional distributions of the mineral assemblages have a direct bearing on the dating of the cave by thermoluminescence and electron spin resonance

ash deposits in hayonim and kebara caves israel macroscopic microscopic and mineralogical observations and their archaeological implications abstract a study of the hearths and ash layers preserved in hayonim and kebara caves israel showed that they are composed of one or several different minerals these include the polymorph of caco3 calcite a variety of phosphate minerals and a suite of siliceous minerals the major component of the latter are siliceous aggregates that are present in wood detailed studies of the mineral associations in these fossil ash layers as well as in fresh wood ash using optical and scanning electron microscopy in the back scattered electron mode together with elemental analyses showed that ash in these caves undergoes a series of diagenetic changes the best preserved ash layers resemble fresh ash and are composed mainly of calcite with minor amounts of siliceous minerals the calcite reacts with phosphate rich solutions to form carbonated apatite and with time the latter dissolves and a variety of other phosphate containing minerals form with each diagenetic change some of the more soluble minerals are lost and ultimately only the ash derived siliceous minerals remain in both caves there are local accumulations of such siliceous minerals that are metres thick in fact ash derived minerals in general are major components of the sediments in both kebara and hayonim caves their diagenesis involves a hugh reduction in volume which in turn may have important effects on the geological structures and stratigraphy of the sediments the changing mineralogy of the sediments due to diagenesis complicates the use of present day estimates of radiation content of the sediments for correcting age estimates by thermoluminescence and electron spin resonance finally the presence of the relatively stable ash derived siliceous minerals in a sedimentary layer in other caves could be a useful means of identifying the presence of ash in other archaeological sites where macroscopic hearth features are absent

the middle stone age human remains from diepkloof rock shelter western cape south africa in the course of recent excavations at diepkloof rock shelter south africa three human remains were found in the middle stone age layers these human remains are two pedal phalanges intermediate and distal from a fifth ray which belong to the same individual and a deciduous first lower molar the layers in which they were found represent the end of the howiesons poort and the beginning of post howiesons poort occupation and are radiometrically dated to mis 3 between 45 and 65 kyr ago they are thus very close in time to the assumed period of anatomically modern humans amh dispersal out of africa into eurasia a period for which very few remains are available in the african fossil record here we describe these new remains and compare their morphology and dimensions to samples of african and eurasian pleistocene and holocene humans our results show that the human remains from diepkloof rock shelter fall well within the range of variation of amh the phalanges are of very small size and indistinguishable from those of recent humans in addition our analysis of the dm1 underlines a large size variation at the end of the mis 4 beginning of the mis 3 in the western cape the discovery of human remains at diepkloof rock shelter albeit limited to three small bones enriches a poorly represented chronological period of the african hominin fossil record

heat treatment in the south african middle stone age temperature induced transformations of silcrete and their technological implications abstract it was recently found that silcrete raw material was heat treated during the south african middle stone age msa for altering its flaking properties this finding led to hypotheses about the implications for the msa hunter gatherers such as the cost of thermal treatment in terms of investment and firewood to date these hypotheses lack a solid basis for data on the thermal transformations of south african silcrete and hence the necessary heating procedure and heating environment is missing in order to produce such data we conducted an experimental study within the framework of the diepkloof project this work is based on the petrographic mineralogical and structural analysis of south african silcrete from the west coast and its thermal transformations our results shed light on the nature of these transformations the ideal heating temperatures and the tolerated heating speed the processes occurring in silcrete are comparable to flint i e the loss of chemically bound water and the formation of new si o si bonds but their intensity is less pronounced effective heating temperatures are significantly higher than for flint and the heating speed tolerated by south african silcrete is relatively fast these findings imply that silcrete heat treatment cannot be directly compared with flint heat treatment unlike flint heating silcrete does not require the setup of a dedicated heating environment and may have been performed in the same time as other fire related activities this would represent only a minor supplementary investment in time and firewood these results have broad implications for the discussion about technological evolution and the acquisition of specialised knowledge in the msa

buried in ashes site formation processes at lapa do santo rockshelter east central brazil few archaeological sites in the americas contain high concentrations of human burials dating back to the early holocene the tropical karstic region of lagoa santa in central brazil state of minas gerais is one of the richest bioanthropological records available to study the behaviors and funerary practices of early holocene south americans with more than 200 skeletons found so far one of the key locations to examine the history of human settlement in lagoa santa is the site of lapa do santo a rockshelter known to contain the oldest rock art and the earliest evidence of funerary complexity in the continent in this geoarchaeological investigation we focus on the early holocene settlement at lapa do santo 7 9 12 7 cal kybp applying high resolution geoarchaeological techniques such as micromorphology organic petrology and ftir on both archaeological modern reference and experimental samples this is the first time that a micro contextual approach integrated with experimental geoarchaeology has been applied to study the formation of rockshelter deposits in a tropical setting our results show that the stratigraphic sequence formed under the dual influence of anthropogenic sedimentation through continuous combustion activities and geogenic sedimentation in the form of oxisol aggregates which fell from above the limestone cliff into the rockshelter intact hearths and remobilized combustion debris possibly hearth rake out are close to the graves suggesting repeated burning activities as part of the ritual behavior of early holocene south americans large amounts of ash are intermixed with heated and unheated oxisol aggregates heated termite mound fragments were also found mixed within the sediments post depositional alteration of the site includes limited bioturbation and localized low energy surface water and sub surface concentrations of moisture leading to precipitation of dense secondary carbonates the age inversions can be attributed to the human action of reworking the ashy sediments and not to post abandonment processes despite this the overall preservation of the sediments is good and most human burials can be considered to be in primary context

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

is it possible to identify temporal differences among combustion features in middle palaeolithic palimpsests the archaeomagnetic evidence a case study from level o at the abric romani rock shelter capellades spain abstract archaeomagnetic dating is probably one of the most known applications of magnetic methods to archaeology but there are others still underutilized and of particular interest to palaeolithic archaeology here we report a novel application of archaeomagnetism as a technique to determine temporal diachronies among combustion features from the same surface within palaeolithic palimpsests the approach is based on the subtle directional changes of the earth s magnetic field through time secular variation sv and on the ability of burned materials to record such variations under certain conditions three middle palaeolithic hearths from level o ca 55 ka bp at the abric romani rock shelter ne spain were archaeomagnetically investigated the studied surface black homogeneous carbonaceous facies recorded the magnetic enhancement produced by fire with a tenfold increase in concentration dependent magnetic parameters in the uppermost centimetre with respect to its unburned or deeper counterparts pseudo single domain psd ti low titanomagnetite was identified as the main remanence carrier the irreversibility of thermomagnetic curves suggests that these samples did not undergo enough high temperatures as to record a full thermoremanence trm additionally the occasional occurrence of maghaemitized magnetite is interpreted as an indication of a thermochemical remanent magnetization tcrm making these samples unsuitable for absolute palaeointensity determinations two well defined 95

aspects of the chemical and microscopic characteristics of plant ashes found in archaeological soils abstract ash from plants occurs in archaeological soils all over the world it is particularly significant in cave deposits but is also found on open air sites where dissolution has been discouraged by aridity deep burial or calcareous surrounding sediments this paper describes the main microscopic characteristics of ash as well as providing details and illustrations of their origin from plant mineral and organomineral compounds chemical summaries are presented which reflect the major trends in phytomineralogy and highlight some additional groupings running through plant physiology emphasis is placed on the importance of understanding the complete range of transformations acting on ash as a result of heating and cooling followed by weathering and dissolution finally some future directions for ash research are suggested both from within the central topic of plant ashes and extending to other types of ash

solubilities of bone mineral from archaeological sites the recrystallization window abstract bone mineral solubility is an important parameter for understanding the preservation of bones in the archaeological and palaeontological records in this study we have measured the solubility of the carbonated hydroxyl apatite of sub recent and fossil bones as well as synthetic hydroxyl apatite in deionized water and in ph buffered solutions the solutions were open to the atmosphere and the ph values were around neutral measurement conditions that are relevant to bone mineral preservation in nature but that were absent from most previous studies we obtained internally consistent results from both the water and the buffered experiments supporting the notion that we are measuring an inherent property of the mineral phase we found that bone mineral is much more soluble than synthetic hydroxyl apatite we measured the ionic activity products at steady state conditions and we identify a recrystallization window between ph 7 6 and 8 1 which defines the conditions under which bone crystals dissolve and reprecipitate as a more insoluble form of carbonated hydroxyl apatite as these conditions are common in nature most fossil bones will not maintain their original crystals with time we also found that bones that contained small amounts of calcite did not dissolve at all during our experiments these results provide a basis for better understanding the conditions in sediments under which bones are preserved and the relative states of preservation of bone they also have important implications for the selection of the most appropriate bone samples for paleoenvironmental and paleodiet analyses and dating

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

the black layer of middle palaeolithic combustion structures interpretation and archaeostratigraphic implications certain aspects of the formation processes of simple flat archaeological combustion structures such as those present in the middle palaeolithic record remain unexplained such kind of combustion structures are commonly affected by postdepositional agents and often their only distinct well preserved component is a thin black lens on the ground hence understanding the nature of this black lens is essential towards archaeological interpretation from an interdisciplinary microstratigraphic approach we present a case study in which for an entire experimental series of flat combustion structures the black layer represents the fire altered topsoil on which the fire was made parallel analysis of archaeological middle palaeolithic combustion structures from the site of el salt alicante spain reveal similar patterns leading to significant implications for archaeological interpretation in the light of these results special attention must be paid to the formation processes of flat middle palaeolithic combustion features as black layers and the material contained in them are not necessarily linked with combustion but with preceding activities or events in such cases black layers represent intact remnants of occupation surfaces concealing significant behavioural and palaeoenvironmental information relevant to the reconstruction of middle palaeolithic societies

an experimental micromorphological investigation of bedding construction in the middle stone age of sibudu south africa abstract we conducted experiments to compare the micromorphological signatures of modern burnt sedge and grass bedding to laminated layers of carbonized material and phytoliths in middle stone age deposits at the shelter sibudu the experiments were designed to clarify the formation processes associated with the laminated layers and to investigate whether these previously identified layers of bedding were deliberately burned or not the results indicate that the laminated layers were most likely produced by human activity related to the construction maintenance and burning of bedding furthermore our experiments demonstrate that large volumes of vegetal material could have produced the relatively thin archaeological deposits of burnt bedding

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

phytolith evidence for hearths and beds in the late mousterian occupations of esquilleu cave cantabria spain esquilleu cave site has provided a moderately well preserved archaeological cave deposit from the late pleistocene in the cantabrian area phytolith quantification identification and determination of the refractive index have been carried out together with ftir analyses from sediment samples collected in the profile the comparison of the data obtained with the previous micromorphological results allows us to make inferences about the site formation processes and the neanderthals use of the cave phytolith results show the presence of grass leaves nearby the hearth suggesting the repetitive existence of a bedding zone on the same area neanderthal behavioral patterns should be revised on the light of high resolution analyses since diagenetic processes can obscure the existence of differentiated activity areas in the site

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

stable carbon and oxygen isotopic compositions of wood ash an experimental study with archaeological implications abstract wood ash composed mainly of the mineral calcite is an important component in many archaeological sites identification of wood ash in the archaeological record is often difficult due to mixing of ash with other calcitic components of geogenic origin and or due to diagenetic changes a recent empirical study using the stable isotope compositions of carbon 13 c and oxygen 18 o in wood ash enabled the identification of mixtures of wood ash with geogenic calcite and to follow diagenetic changes due to partial dissolution and re precipitation of ash in two prehistoric cave sites in israel little however is known about the processes responsible for the isotopic compositions of wood ash in relation to formation at various temperatures and the influence on isotopic composition of ash from a variety of plant species here we present an experimental study of wood ash formed by burning three c3 tree species and one c4 desert bush at different temperatures the results indicate that there are significant differences in the isotopic compositions of carbon and oxygen between wood ash that forms by combustion at a relatively low temperature 500 c and at a higher temperature 900 c in addition we show that the isotopic composition of carbon and oxygen in high temperature wood ash approaches equilibrium over a period of several months and that the carbon isotopic composition of low temperature wood ash may reflect the photosynthetic pathway of the burnt woody species lastly we show that the isotopic compositions obtained from wood ash prepared at different temperatures do not reflect a temperature dependent fractionation process but a mixing line between calcite that formed by low temperature combustion and calcite formed by high temperature combustion which later underwent re carbonation with atmospheric co 2 in addition we suggest that exchange processes may possibly occur during combustion between decomposing calcium oxalate and atmospheric o 2 co 2 and co the archaeological implications of this study are discussed in relation to identification of wood ash in the archaeological record identification of fuel sources and burning temperatures and diagenetic changes expected in karstic cave environments the method presented here can be applied at any archaeological site

technological successions in the middle stone age sequence of diepkloof rock shelter western cape south africa the southern african msa comprises a series of phases of unique technological innovations that fuel current models on the evolutionary processes of anatomically modern humans however the nature and variability of these technological phases remain poorly documented this study reports on the previously unpublished sequence of diepkloof rock shelter south africa and investigates the main technological changes therein particularly emphasizing the emergence succession and disappearance of the still bay sb and the howiesons poort hp we argue for technological change that occurred at different rates and under the influence of variable driving factors our model implies that the sb and the hp are not related to the influx of new populations but have regionally specific origins unlike the other techno complexes the hp at diepkloof is subdivided into different phases early intermediate and late but only the upper phases resemble the so called classic hp finally the technological sequence of diepkloof questions the homogeneous picture which has been so far assumed for the southern african msa and places emphasis on the importance of exploring long regional sequences

a study of pleistocene and holocene hyaena coprolites abstract hyaena coprolites from a diachronic series of archaeological sites in israel were examined and compared with recent faecal material from striped hyaena dens and zoos three methods were applied in the analysis of all samples gross morphometrical attributes x ray diffraction and petrological thin sections this last method is an innovation in the field of coprolite studies and facilitates the long term preservation of the original textural characteristics and fabric of sections of the coprolite the combination of these three approaches facilitated among other things the assessment of hyaena diet in the past as well as in the present and determination of local environmental factors affecting the composition of the coprolite we also obtained some indication of changes related to ageing of the material

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

initial micromorphological results from liang bua flores indonesia site formation processes and hominin activities at the type locality of homo floresiensis liang bua a karstic cave located on the island of flores in eastern indonesia is best known for yielding the holotype of the diminutive hominin homo floresiensis from late pleistocene sediments modern human remains have also been recovered from the holocene deposits and abundant archaeological and faunal remains occur throughout the sequence the cave the catchment in which it is located and the gross aggradational phases of the sediment sequence have all been subject to a great deal of scientific scrutiny since the discovery of the holotype of h floresiensis in 2003 a recent program of geoarchaeological research has extended analyses of the site s deposits to the microstratigraphic micromorphological level the stratigraphic sequence in the cave is well defined but complex comprising interstratified sediments of diverse lithologies and polygenetic origins including volcanic tephras fine grained colluvium coarse autogenic limestone gravels speleothems and anthropogenic sediments such as combustion features the sedimentological and chemical heterogeneity suggest that processes of site formation and diagenesis varied markedly through time both laterally and vertically we present initial results from samples collected in 2014 from an excavation area near the rear of the cave which yielded radiocarbon ages from charcoal that fill an important temporal gap in the chrono stratigraphic sequence of previously excavated areas of the site the results indicate marked changes in site environment and hominin activity during the late pleistocene relating primarily to the degree to which the cave was connected to the hydrogeological system and to the varying intensities of use of the cave by hominins importantly we identify anthropogenic signs of fire use at the site between 41 and 24 thousand years ago most likely related to the presence of modern humans

basaltic sill sediment complexes in young spreading centers genesis and significance in contrast to mature mid oceanic ridges where magmatic activity is little affected by the slow accumulation of sediments in young spreading centers such as that of the guaymas basin in the gulf of california the basaltic magma of great magmatic pulses forms dikes and sills within the uppermost few hundred metres of soft sediments in general younger dikes and sills are injected next to or on top of the contact zone of the older ones in this manner a distinctive sill sediment complex is built up the sediments of which are rather compacted and partly metamorphosed despite the low burial depth the thickness of this transitional zone between the sheeted dike complex seismic layer 2 and younger sediment seismic layer 1 is controlled chiefly by the rates of sedimentation and spreading if the half spreading rate is approximately one order of magnitude greater than the sedimentation rate the sill sediment complex can reach a thickness of only a few hundred metres and the depth of the spreading trough remains approximately constant sedimentation rates approaching or surpassing the spreading rate cause filling up of the basins which probably hampers the injection of magma into sediments sill sediment complexes similar to those in the gulf of california are also expected to occur at the passive margins of older oceanic basins as well as orogenic belts

investigation of organic matter and biomarkers from diepkloof rock shelter south africa insights into middle stone age site usage and palaeoclimate the file associated with this record is under embargo until 36 months after publication in accordance with the publisher s self archiving policy the full text may be available through the publisher links provided above

on the expected structure of extreme waves in a gaussian sea part ii swade scanning radar altimeter measurements abstract in a previous paper phillips et al an approximate theory was developed that predicted that the expected configuration of extreme waves in a random sea or the average configuration of an ensemble of extreme waves is proportional to the space time autocorrelation function of the surface displacement of the wave field as a whole this result is tested by examination of scanning radar altimeter measurements made during swade in four different sea states including a unimodal mature wave field a short fetch a wind generated sea crossing swell a very broad directional spectrum and a fetch limited wind sea with opposing swell in each of these the spatial autocorrelation function was found directly from the sra data the highest waves in each dataset were selected and their configurations averaged with respect to the crest these averaged configurations were in each case found to be consistent with the autocorrelation function

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