the twin rivers kopje zambia stratigraphy fauna and artefact assemblages from the 1954 and 1956 excavations abstract earlier lupemban assemblages from brecciated fissure sediments on twin rivers kopje are of great interest in view of the appreciably greater antiquity recently suggested for the earlier middle stone age the twin rivers assemblages are compared with those from kalambo falls the congo basin and zimbabwe the assemblages combine components from both the forested grasslands of equatoria and the savanna woodlands of east and south central africa faunal remains suggest that the early middle stone age sequence reflects several episodes of climatic change between 130 000 years bp and bp

chemical composition and stratigraphic correlation of mesozoic basalt units of the newark basin new jersey and the hartford basin connecticut summary new major and trace element analyses of the messozoic basalts of the hartford basin of connecticut the talcott holyoke and hampden basalts indicate that the basalts are chemically very similar to the mesozoic basalts of the newark basin of new jersey the first second and third watchung basalts our geochemical data impose some constraints on any time stratigraphic correlation of the basalts in the two basins we suggest that the holyoke and second watchung basalts are fractionation products of a talcott first watchung parent magma we also suggest that the hampden and third watchung basalts are synchronous fractionation products of a magma unlike any of the eastern north american basalt types described in the literature but they may instead be the fractionation products of a magma resembling a magma of the same type as that of the mid atlantic ridge from a petrologic standpoint the most straight forward time stratigraphic interpretation is a one to one correlation of the three flows of the newark basin with the three flows of the hartford basin our geochemical and petrologic evidence is particularly supportive of time stratigraphic correlations between the first watchung and the talcott basalts and between the third watchung and the hampden basalts our data however are not inconsistent with the possibility that the second watchung may be slightly older than the holyoke basalt

optical dating of geoarchaeologically significant sites from the southern high plains and south texas usa the southern high plains of the united states is a key region for the investigation of early human occupation of north america this area including selected archaeological sites located in southern texas contains a range of aeolian fluvial and playa deposits such deposits may be suited to luminescence based methods of age assessment in this paper we describe a combination of multiple and single aliquot optical dating results for a selection of sites with some independent age control we find generally good agreement between multiple and single aliquot equivalent dose de estimates for the 20 samples compared but note that the single aliquot approach results in errors in mean de s to be less by an order of magnitude our results suggest that at least some of the single aliquot methods are of great utility for low latitude geoarchaeological sites

early acheulean technology at es2 lepolosi ancient mhs bayasi in peninj lake natron tanzania abstract the aim of this paper is to undertake the technological description of es2 lepolosi one of the acheulean sites located on the sambu escarpment in the lake natron basin tanzania and dated to 1 5 1 4 ma through the combination of three different lithic collections glynn isaac s 1961 81 dominguez rodrigo s 1999 2002 and the sample retrieved during our own excavations carried out between 2007 and 2011 we provide here a comprehensive description of the technological characteristics seen in this classic african early acheulean site sedimentological archaeostratigraphic and soil micromorphological information acquired during the course of the 2008 2011 fieldwork is used as a contextual framework for assessing the environmental and post depositional history of the site

renewed investigations into the middle stone age of northern malawi j desmond clark and his colleagues were first to investigate the rich middle stone age msa from ca 285 to 30 000 years ago deposits in the karonga district of northern malawi in the 1960s this work demonstrated the enormous potential of the area to inform about middle to late pleistocene hominin lifeways but further studies were hindered by difficulties in dating the sites and understanding their fine scale depositional and paleoenvironmental contexts with the advances that have been made in the fields of geoarchaeology lithic analysis palaeoenvironments and geochronology over the last fifty years the time is ideal to renew these investigations recent survey and excavation in karonga malawi show that msa lithic artifacts are preserved in a variety of stratified sedimentary contexts and that they exhibit limited weathering or other indications of post depositional transport these deposits are in close proximity to the high resolution paleoenvironmental records derived from sediments at the bottom of nearby lake malawi which provide context for the human behavior recorded by the artifacts results of excavations at one of these stratified sites the airport site are detailed here this provides a renewed example of the site formation and behavioral data available in the region

quantitative measures of textural anisotropy resulting from magmatic compaction illustrated by a sample from the palisades sill new jersey abstract early in the crystallization of many tholeiitic basaltic magmas plagioclase crystals cluster together into a 3 d cellular network which forms a passive marker capable of recording the deformation that accompanies compaction of crystal mush although irregular in detail the overall network is initially isotropic and only becomes anisotropic as a result of compaction we have developed four independent methods to quantify the 3 d textural anisotropy of a basalt sample using at least three non parallel thin sections three of the methods are based on the geometrical properties of digitized maps of the feldspar chain networks one approach focuses on the angular variation of the mean intercept along parallel traverses through the network another examines the orientation and size distribution of individual links and the third considers the average shape of interstitial regions outlined by the plagioclase network the fourth technique approximates the textural anisotropy by the variogram anisotropy of a scanned thin section image we illustrate the methods using five oriented non parallel thin sections from a sample of diabase 146 m above the base of the 300 m thick palisades sill of new jersey compaction of crystal mush in this sill has previously been postulated on the basis of chemical evidence the 3 d feldspar network anisotropy based on the first three approaches suggests nearly uniaxial compaction on the order of 8 6 in a direction within 3 of the intersection of the columnar joints at the sample site a rigorous statistical test based on the statistics of elliptically contoured non normal multivariate distributions documents that the link vector distribution in vertical sections are statistically anisotropic at a 95 confidence level and that the overall compaction is 7 9 2 6 the orientation and magnitude of the 3 d textural anisotropy determined by the image variogram of the non opaque minerals is almost identical to the mean feldspar network anisotropy 8 5 compaction in a direction 10 from the columnar joint intersections the major silicate textural and feldspar network anisotropy axes both plunge almost directly down dip of the sill on the other hand the major axis of the variogram anisotropy of the opaque minerals is approximately parallel to the strike of the sill and to the major axis of the anisotropic magnetic susceptibility the anisotropy of the silicate mineral fabric may reflect down dip flow of a deformable melt rich crystal mush whereas the ams and opaque textural anisotropy reflects the influence of gravitational stresses during the growth of magnetite in the final stages of melt crystallization evidently the palisades sill was not originally horizontal but was intruded in an orientation close to its present attitude

sequential crystal overproduction triggering mg cr ti v p mree enrichment in a single pulse tholeiitic mafic sill in the central iberian zone spain abstract we study the causes of mg cr ti v p mree enrichment in a 134 m thick mafic sill emplaced in a single magma pulse whole rock chemistry indicates that tio2 up to 5 51 wt and p2o5 up to 1 60 wt enrichment occurred in a closed system immiscibility processes during magmatic crystallization and interaction with late fluids seem to have played little or no role for the ti p distribution liquid lines of descent for anhydrous and hydrous conditions reveal that the melt did not follow a fenner trend anhydrous which may lead to strong ti or p enrichment but a bowen trend hydrous during crystallization at low fo2 fmq 2 and low water contents 0 5 h2o the mg cr ti v p mree rich samples are cumulates and their composition is offset from the liquid line of descent due to postcumulus compaction and compositional convection theoretical formulation of compaction and compositional convection demonstrates that classical postcumulus scenarios of strong undercooling sill cr ti v or p mree rich cumulates the efficiency of postcumulus processes declines once the latent heat does not compensate heat loss to the country rock leading to cumulates with high intergranular liquid fractions and without cr ti and p enrichment high water contents in the upper level of the sill facilitate postcumulus processes and migration of residual liquids and fluids upwards leading to the formation of abundant pegmatoid pockets and the development of a sandwich horizon that does not follow the liquid line of descent

pegmatoid and gabbroid layers in jurassic preakness and hook mountain basalts newark basin new jersey abstract coarse grained segregations are found in several subaerial flows of jurassic flood basalts in the watchung mountains new jersey they are particularly common within a 140 180 m thick quartz tholeiitic preakness flow the thickest of the watchung flows the segregations are enriched in iron and depleted in aluminum compared with the enclosing basaltic rock and are composed of pyroxene plagioclase and magnetite in a dark fine grained interstice most of the segregations are characterized by a 0 1 0 6 cm gabbroid crystal size range but a few lenses are characterized by a 0 4 2 cm pegmatoid size range three types of coarse grained segregations are found within the thickest preakness flow type 1 vesicular horizontal sheets 2 m typically 5 20 cm thick within the upper 40 m of the flow type 2 a thick 10 30 m mappable but discontinuous nonvesicular layer located at the contact of the colonnade with the overlying entablature and type 3 very thick up to 96 m lens shaped accumulations

early and middle pleistocene environments and hominid biogeography micromammalian evidence from kabwe twin rivers and mumbwa caves in central zambia abstract kabwe broken hill has been famous since 1921 for yielding the cranium of broken hill man the occurrence of micromammals at this site was reported at the time although they were never studied in detail twin rivers was excavated originally by j d clark in 1954 and recently by l s barham the material discussed comes from the latter excavation the environmental interpretation agrees with evidence from mumbwa caves that all the samples were accumulated under conditions similar to those of the present this may indicate that early and middle pleistocene homo spp only occupied central zambia during interglacial periods as they apparently did northern south africa other possibilities are that conditions at low latitudes did not change appreciably between interglacial and glacial periods or that evidence for occupation during the glacial periods must be sought close to permanent water sources where hominids would have sought refuge from drought it is further postulated that early and middle pleistocene homo spp moved among tropical and subtropical savanna habitats using rivers and lakes rather than rift valleys per se as migration routes

evolution of tholeiitic diabase sheet systems in the eastern united states examples from the culpeper basin virginia maryland and the gettysburg basin pennsylvania abstract high tio 2 quartz normative htq tholeiite sheets of early jurassic age have intruded mainly late triassic sedimentary rocks in several early mesozoic basins in the eastern united states field observations petrographic study geochemical analyses and stable isotope data from three htq sheet systems in the culpeper basin of virginia and maryland and the gettysburg basin of pennsylvania were used to develop a general model of magmatic differentiation and magmatic hydrothermal interaction for htq sheets the three sheet systems have remarkably similar major oxide and trace element compositions cumulus and evolved diabase in comagmatic sheets separated by tens of kilometers are related by igneous differentiation differentiated diabase in all three sheets have petrographic and geochemical signatures and fluid inclusions indicating hydrothermal alteration beginning near magmatic temperatures and continuing to relatively low temperatures sulfur and oxygen isotope data are consistent with a magmatic origin for the hydrothermal fluid the three sheet systems examined apparently all had a similar style of crystal liquid fractionation that requires significant lateral migration of residual magmatic liquid the proposed magmatic model for htq sheets suggests that bronzite laden magma was intruded in an upper crustal magma chamber with bronzite phenocrysts collecting in the lower part of the magma chamber near the feeder dike early crystallization of augite and ca poor pyroxene before significant plagioclase crystallization resulted in density driven migration of lighter residual magmatic liquids along lateral and vertical pressure gradients towards the upper part of the sheet the influence of water on the physical properties of the residual liquid including density viscosity and liquidus temperature may have facilitated the lateral movement more than 15 km up dip in the sheets exsolution of a cl and s rich metal bearing aqueous fluid from residual magma resulted in concentration and redistribution of incompatible and aqueoussoluble elements in late stage differentiated rocks this proposed hydrothermal mechanism has important economic implications as it exerts a strong control on the final distribution of noble metals in these types of diabase sheets

complex layering of the orange mountain basalt new jersey usa the orange mountain basalt of new jersey is a mesozoic formation consisting of three units a single lower inflated sheet lobe about 70 m thick omb1 a middle pillow basalt about 10 to 20 m thick omb2 and an upper compound pahoehoe flow about 20 to 40 m thick omb3 the orange mountain basalt is part of the central atlantic magmatic province quarry and road cut exposures of omb1 near paterson new jersey display some unusual layering that is the focus of this study omb1 exposures displays the typical upper crust core and basal crust layers of sheet lobes but throughout the patterson area also display distinct light gray layers of microvesicular basalt mineralized with albite directly over the basal crust and under the upper crust the lower microvesicular layer is associated with mega vesicular diapirs we propose that the upper and lower microvesicular layers were composed of viscous crust that was suddenly quenched before it could devolatilize immediately before the solidification of the core during initial cooling the bottom of the basal layer was mineralized with high concentrations of calcite and albite during a high temperature hydrothermal event subsequent albitization as well as zeolite prehnite and calcite precipitation events occurred during burial and circulation of basin brine heated by recurring palisades magmatism below the orange mountain basalt some of the events experienced by the orange mountain basalt are unusual and place constraints on the fluid dynamics of thick flood basalt flows in general the late penetration of vesicular diapirs through the entire thickness of the flow interior constrains its viscosity and solidification history

vegetation response to glacial interglacial climate variability near lake malawi in the southern african tropics abstract pollen records from lake malawi africa spanning the last 135 kyr show substantial and abrupt vegetation response to multiple episodes of extreme aridity between 135 and 75 ka peaks in both the relative abundance and total production of podocarpus pollen define the first two of these drought episodes from 135 to 127 and again from 117 to 105 kyr bp podocarpus percentages remain above 16 with peak values as high as 38 indicating a period marked by a cool climate resulting in expansion of montane forest taxa to lower elevations marine palynological records from the angola margin and congo fan show similar peak podocarpus percentages at this time oxygen isotope stage 5d indicating a similar climate across the african continent at this latitude from 105 to 90 ka continuing drought resulted in total pollen accumulation rates in lake malawi to fall to less than 300 grains cm2 yr of predominately grass pollen this episode in african history was severe enough to cause the disappearance of pteridophytes and forest taxa such as uapaca and brachystegia as well as montane taxa podocarpus olea spp and ericaceae within the pollen source area of lake malawi these taxa all remain nearly absent from the surrounding vegetation for the next 18 000 years the resultant semi desert vegetation would have been inhospitable for early humans living within or traveling through the lake malawi region increasing moisture following these arid intervals allowed expansion creation and maintenance of a more diverse landscape vegetation mosaic around lake malawi including zambezian miombo woodland humid evergreen woodland and afromontane forests the relative abundance of each fluctuated in response to either cooling i e afromontane expansion from 60 to 56 ka or moisture balance i e increasing humid evergreen woodland between 75 and 65 ka notably there was no significant change in vegetation composition during the last glacial maximum lgm 30 15 ka as compared to the previous 20 000 years

cooling history and differentiation of a thick north mountain basalt flow nova scotia canada a thick 175 m north mountain basalt flow at mckay head nova scotia canada shows 25 cm thick differentiated layers separated by 130 cm of basalt in its upper 34m upper layers 5 m below the lava top are highly vesicular whereas lower ones are pegmatitic and contain a thin 2 cm rhyolite band the layering of the flow closely resemble that of some hawaiian lava lakes the eesicular basalts and mafic pegmatites are inferred to be liquid rich segregations which drained into horizontal cracks that formed within a crystalline mush the cracks resulted from a thermal contraction associated with cooling and shrinkage of the mush rhyolites were formed by in situ differentiation gas overpressures fractured the pegmatites and gas effervescence filter pressing forced silicarich residual liquid from pegmatite interstices into the fractures creating bands chemical differences between the pegmatitic layers and early formed highly differentiated upper vesicular layers may reflect a role for volatiles in the differentiation process along with crystal fractionation

scientific drilling in the great rift valley the 2005 lake malawi scientific drilling project an overview of the past 145 000years of climate variability in southern hemisphere east africa abstract the recovery of detailed and continuous paleoclimate records from the interior of the african continent has long been of interest for understanding climate dynamics of the tropics and also for constraining the environmental backdrop to the evolution and spread of early homo sapiens in 2005 an international team of scientists collected a series of scientific drill cores from lake malawi the first long and continuous high fidelity records of tropical climate change from interior east africa the paleoclimate records which include lithostratigraphic geochemical geophysical and paleobiological observations documented in this special issue of palaeo3 indicate an interval of high amplitude climate variability between 145 000 and 60 000 years ago when several severe arid intervals reduced lake malawi s volume by more than 95 these intervals of pronounced tropical african aridity in the early late pleistocene around lake malawi were much more severe than the last glacial maximum lgm a well documented period of drought in equatorial and northern hemisphere tropical east africa after 70 000 years ago climate shifted to more humid conditions and lake levels rose during this latter interval however wind patterns shifted rapidly and perhaps synchronously with high latitude shifts and changes in thermohaline circulation this transition to wetter more stable conditions coincided with diminished orbital eccentricity and a reduction in precession dominated climatic extremes the observed climate mode switch to decreased environmental variability is consistent with terrestrial and marine records from in and around tropical africa

geochemical reversals within the lower 100 m of the palisades sill new jersey transects through the lower part of the palisades sill were made at fort lee and alpine new jersey in order to characterize the petrologic signature of previously proposed reversals in the normal tholeiitic differentiation trend petrographic and geochemical data include 1 modal and grain size analyses 2 bulk rock major and trace element concentrations by dcp aes and 3 augite orthopyroxene magnetite and olivine compositions by electron microprobe analysis anomalous horizons defined by increased bulk rock mg cr ni and co concentrations and abrupt modal and grain size changes occur at 10 m the well known olivine zone 27 m 45 m and 95m above the basal contact thermal models coupled with estimates of the emplacement rate and total magma volume indicate that the olivine zone oz is an early stage feature related to the emplacement of initial magma into the palisades chamber stoke s law calculations indicate that the settling velocity of average sized olivine crystals in a high titanium quartz normative htq magma is too slow for significant gravity settling to have occurred prior to the solidification of the basal 20 m of the sill it is suggested that the oz resulted from the emplacement of a heterogeneous initial magma from a compositionally stratified sub palisades storage chamber located within the upper crust however heterogeneity may have been derived directly from the mantle or during rapid ascent geochemical models indicate that the oz contains accumulated olivine that is not in cotectic or constant proportions with the other cumulus phases suggesting a mechanical sorting process magma chamber recharge is proposed to have occurred at the 27 m and 45 m levels when a slightly more primitive htq magma was injected into the palisades sill chamber zones of elevated mg and cr 6 to 10 m thick at these two horizons may indicate the thickness of the hybrid magma formed by the mixing of these two compositions geochemical models indicate that the rocks at these levels have accumulated excess orthopyroxene relative to samples from the rest of the sill normal faulting in the fort lee area at the 95 m level has caused repetition of the stratigraphic section and hence the sharp reversal observed at this level

cosmogenic nuclide age constraints on middle stone age lithics from niassa mozambique abstract the late phases of the middle stone age msa in the east african rift system ears are known for their evolutionary shifts and association with bottlenecks transcontinental expansion and climatic fluctuations the chronology of msa sites contemporaneous with these eco demographic upheavals is uncertain because of the scarcity of datable sites and the poor understanding of their depositional and erosional histories we apply terrestrial cosmogenic nuclide dating in a stratigraphic section with a complex exposure history to the study of the luchamange beds a widespread sedimentological unit underlying msa sites from the shores of lake niassa mozambican ears we use an innovative approach which may be applicable elsewhere to calculate their age using a monte carlo based bayesian model that links depth profiles of 26al and 10be and uses other geomorphic and cosmogenic nuclide age constraints on episodic erosion and burial the age of the basal luchamange beds is 42 77 15 ka and the msa occupation on top is 29 3 11 ka these dates suggest temporal overlap between msa and the earliest later stone age and diversity in cultural manifestations at the end of the msa

classic and new dating methods for assessing the temporal occurrence of mass movements abstract establishing landslide chronologies is essential both for understanding causes of mass movements as part of fundamental geomorphological research and for the assessment of landslide hazards as part of applied geomorphology we discuss the applicability of different methods for determining landslide chronologies frequencies and dynamics in relation to the type of material being dated sampling location and type of mass movement the emphasis is on the possibilities and limitations of the different dating methods established methods such as radiocarbon dating lichenometry and dendrochronology are briefly discussed the paper focuses however on 1 new analytical techniques like accelerator mass spectrometry ams thermally ionising mass spectrometry tims and laser fusion which have led to significant improvements of established dating methods and on 2 new dating methods like optically stimulated luminescence osl dating and alpha recoil track art dating

the site of ain hanech revisited new investigations at this lower pleistocene site in northern algeria abstract new archaeological investigations have been carried out at the oldowan site of ain hanech in northeast algeria the archaeological horizons are delineated and positioned relative to the regional stratigraphy preliminary palaeomagnetic analysis reveals normal polarity for the oldowan occurrences that may be correlated with the olduvai subchron on the indication of the vertebrate faunal biozonation broken up bones associated with stone artefacts and contained in a silty deposit mixed with sand and gravels were excavated from two archaeological sites the bone assemblage includes equids bovids elephant and rhinoceros and dominated by equus tabeti taphonomic patterns indicate that bones were buried rapidly over a period of years and while the site was occupied the lithic artefacts are fresh and represent a coherent assemblage including small debitage the artefacts made of limestone and flint include flaked cobbles whole flakes various fragments and retouched pieces a microwear study undertaken on pieces made of flint indicates the use of two simple flakes and of one denticulate for meat processing the stone artefact assemblage may be considered as a north african variant of the oldowan

technological strategies and the economy of raw materials in the tk thiongo korongo lower occupation bed ii olduvai gorge tanzania abstract at tk 113 m2 were excavated in 2010 2012 in the two areas immediately adjacent to the trenches dug by m leakey in 1963 extensive lithic and faunal assemblages were retrieved from several levels of the archaeological site tk is located at the exposed top of olduvai s bed ii recently dated to 1 353 0 035 ma from a geo archaeological perspective the stratigraphic studies have provided a redefinition of the processes involved in the site s formation this paper offers a geological interpretation that revises and amends previous ones the new interpretation focuses particularly on the technological and paleoeconomic study of a new lithic assemblage recovered from the lower occupation level tklf this assemblage comprises 5805 objects in total including 3812 items of shatter we analyse here the chaines operatoires represented in this level as well as the processes implied by the raw materials management maintenance and abandonment of the lithic assemblage the character of the site as well as the activities carried out in it have been greatly influenced by the proximity of the sources of the raw material primarily used which could have been extracted from an inselberg of a particular type of quartzite located within a few hundred meters of the site two different chaines operatoires can be identified in tklf one based on obtaining flakes from varied blanks particularly volcanic rocks and the distinctive quartzite and the second on the manufacture of large and highly standardized bifaces that were produced used and abandoned in the site

middle stone age msa site distributions in eastern africa and their relationship to quaternary environmental change refugia and the evolution of homo sapiens this paper considers the evolution of homo sapiens in eastern africa in relation to refugia and bottlenecks around 200 ka bp at a macro scale middle stone age msa lithics site distributions and locations are analysed in relation to palaeovegetation maps of the last glacial interglacial cycle which are used as a proxy for earlier climate cycles a push and pull model is then postulated for the spread of homo sapiens out of refugia in eastern africa involving both volcanism push and habitat availability pull a date within ois 5 is suggested for this expansion to other parts of the continent and potentially further afield contrary to a frequently proposed expansion within ois 3

the nature of stone lines in the african quaternary record archaeological resolution at the rainforest site of mosumu equatorial guinea abstract stone lines are widespread quaternary features that appear in tropical and subtropical regions they have a diverse nature and genesis and are frequently associated with archaeological assemblages however archaeological deposition and stone line configuration may be unrelated geological events separated by thousands of years the energetics involved in stone line formation coarse and fine material translocation across space and in depth and overall assemblage integrity vary from one site to another this paper presents quantitative and spatial geoarchaeological data from the site of mosumu in the tropical rain forest of continental equatorial guinea mosumu yielded middle and later stone age assemblages dated to at least the last 30 000 years in a stone line context special attention to the study of vertical and horizontal variations of artifacts sedimentary features and taphonomic indicators allows analysis of the nature meaning and archeological resolution at this site the results are placed in the wider debate over the meaning of stone lines in the african quaternary record

taphonomy of micromammals from cave deposits at kabwe broken hill and twin rivers in central zambia samples of middle pleistocene micromammals from cave deposits at kabwe broken hill and twin rivers in zambia were analysed according to andrews s 1990 methods in addition behavioural and ecological data relating to possible predator species were examined for corrobation or contradiction of the mechanical evidence interpretation of the kabwe sample is complicated by its unknown history since recovery and the possibility that the paucity of cranial remains results from their selective post recovery removal from the sample however the combined evidence suggests that it was collected by barn owls whereas the twin rivers material perhaps accumulated at a spotted eagle owl nest site

an experimental investigation into the nature of faceted limestone spheroids in the early palaeolithic abstract at some early palaeolithic sites e g ain hanech algeria and el ubeidiya israel archaeologists have uncovered interesting and enigmatic artefact forms that have received special attention these are the faceted limestone spheroids sometimes called boules a facettes or boules polyedriques these artefacts usually between 5 and 10 cm in maximum dimension and weighing between 250 and 1000 g are characterized by their roughly globular shape and the numerous flake scars on their exterior surface previous interpretations of these forms have suggested that they are intentionally shaped tools representative of an evolved pebble tool stage recent experimental replicative and functional studies of artefacts from the oldowan site of ain hanech in north east algeria have demonstrated that these limestone forms may simply be very exhausted cores from flake production these experiments also highlight that there is a continuum from simple limestone core forms choppers polyhedrons to these heavily reduced cores spheroids in the process of core reduction with the heavily reduced faceted spheroids fairly rare in the overall archaeological assemblage at ain hanech

convection and crystal settling in sills it has been advocated that convective and crystal settling processes play significant and perhaps crucial roles in magmatic differentiation the fluid dynamics of magma chambers have been extensively studied in recent years both theoretically and experimentally but there is disagreement over the nature and scale of the convection over its bearing on fractionation and possibly over whether it occurs at all the differential distribution of modal olivine with height in differentiated alkaline basic sills provides critical evidence to resolve this controversy at least for small to medium large magma chambers our own and others published data for such sills show that irrespective of overall olivine content modal olivine contents tend to increase in a roughly symmetrical manner inwards from the upper and lower margins of the sill i e the distribution patterns are more often approximately d shaped rather than the classic s shape generally ascribed to gravity settling we concur with the majority of other authors that this is an original feature of the filling process which has survived more or less unchanged since emplacement we therefore conclude that the magmas have not undergone turbulent convection and that gravity settling has usually played only a minor modifying role since the intrusion of these sills we offer a possible explanation for the apparent contradiction between fluid dynamical theory and the petrological evidence by suggesting that such sills rarely fill by the rapid injection of a single pulse of magma rather they form from a series of pulses or a continuous pulsed influx over a protracted interval during which marginal cooling severely limits the potential for thermal convection

timing and duration of the central atlantic magmatic province in the newark and culpeper basins eastern u s a abstract new major and trace element data and 40ar 39ar plateau ages constrain the timing duration and time related geochemical evolution of the central atlantic magmatic province in the u s a newark and culpeper basins and refine correlations with basaltic lava flows from other late triassic early jurassic circum atlantic basins the precise statistically robust 40ar 39ar plateau ages were obtained on biotite and on fresh plagioclase and calculated using the latest 40k decay constants these ages are supported by a general consistency of the ca k calculated from 37ar 39ar of the plateau steps and the ca k obtained by detailed electron microprobe analyses on plagioclase phenocrysts the ages of five analyzed basalt lava flows from all three lava flow units in the newark basins and the ages of two sill samples are indistinguishable indicating a brief magmatic peak phase at 201 8 0 7 ma recalibrated 40ar 39ar plateau ages from the entire province indicate a near synchronous onset and peak volcanic activity at the triassic jurassic boundary within the circum atlantic basins from the u s a canada and morocco the early erupted magmas moroccan lower to upper basalts the fundy basin north mountain basalt and orange mountain and equivalent u s a flows yield an enriched geochemical signature e g with relatively high la yb whereas late magmas in the u s a hook mountain and hampden basalts and morocco recurrent basalt yield relatively depleted geochemical compositions low la yb a slight but significant age difference for eruption of hook mountain and hampden basalts 200 3 0 9 ma and recurrent basalts 198 2 1 1 ma is interpreted as evidence of a diachronous northward rift drift transition during break up of pangea our data indicate also a prolonged intrusive sequence that continued until about 195 ma at the palisades sill and is consistent with sporadic late camp magmatism for dykes from the south eastern u s a and for intrusions from guinea

late pleistocene to holocene human palaeoecology in the tropical environments of coastal eastern africa abstract the ecological adaptations that stimulated the dispersal and technological strategies of our species during the late pleistocene remain hotly disputed with some influential theories focusing on grassland biomes or marine resources as key drivers behind the rapid expansion and material culture innovations of homo sapiens within and beyond africa here we present novel chronologically resolved zooarchaeological taxonomic and taphonomic analysis and stable isotope analysis of human and faunal tooth enamel from the site of panga ya saidi c 78 0 4 ka kenya zooarchaeological data provide rare insights into the fauna associated with and utilized by late pleistocene holocene human populations in tropical coastal eastern africa combined zooarchaeological and faunal stable isotope data provide some of the only dated on site archives of palaeoenvironments beyond the arid interior of eastern africa for this time period while stable isotope analysis of humans provides direct snapshots of the dietary reliance of foragers at the site results demonstrate that humans consistently utilized tropical forest and grassland biomes throughout the period of site occupation through a transition from middle stone age to later stone age technological industries and the arrival of agriculture in the region by contrast while coastal resources were obtained for use in symbolic material culture there is limited evidence for consumption of marine resources until the holocene we argue that the ecotonal or heterogeneous environments of coastal eastern africa may have represented an important refugium for populations during the increasing climatic variability of the late pleistocene and holocene and that tropical environments were one of a diverse series of ecosystems exploited by h sapiens in africa at the dawn of global migrations

measurement of 10be from lake malawi africa drill core sediments and implications for geochronology abstract the cosmogenic radionuclide 10 be was measured from drill core sediments from lake malawi in order to help construct a chronology for the study of the tropical paleoclimate in east africa sediment samples were taken every 10 m from the core mal05 1c to 80 m in depth and then from that depth in core mal05 1b to 382 m sediment samples were then later taken at a higher resolution of every 2 m from mal05 1c they were then leached to remove the authigenic fraction the leachate was processed to separate out the beryllium isotopes and 10 be was measured at the tams facility at the university of arizona the 10 be 9 be profile from lake malawi sediments is similar to those derived from marine sediment cores for the late pleistocene and is consistent with the few radiocarbon and osl ir measurements made from the same core nevertheless a strong correlation between the stable isotope 9 be and the cosmogenic isotope 10 be suggests that both isotopes have been well mixed before deposition unlike in some marine sediment cores in addition the correlation of beryllium isotopes to a proxy of lake level toc total organic matter from lake malawi indicates that the concentrations of 10 be in the lake sediments result from the combined effects of global and local climates on lake level local hydrology and sediment transport in the lake malawi basin rather than as a direct response to its production in the atmosphere modulated by the intensity of the earth s dipole therefore a direct correlation of the 10 be 9 be to a chronology derived from the paleomagnetic variations measured from marine sediments was not possible nevertheless a comparison of the 10 be 9 be chronology allowing for decay at lake malawi to that of the global marine paleomagnetic record suggests that the bottom of core mal05 1b is no more than 750 ka in age

evolution of late stage differentiates in the palisades sill new york and new jersey abstract the palisades sill at upper nyack ny contains evolved rocks that crystallized as ferrodiabase and ferrogranophyre and occupy 50 to 60 of the local thickness 143 nd 144 nd isotope values for rocks representing palisades diversity range between 0 512320 and 0 512331 and indicate a homogeneous source for the palisades and little or no contamination from shallow crustal sediments petrographic analysis of ferrodiabase suggests that strong iron enrichment was the result of prolonged quiescence in cycles of magmatic input ferrogranophyres in the updip northern palisades at upper nyack are members of a suite of cogenetic rocks with similar composition to sandwich horizon rocks of the southern palisades at fort lee nj but display distinct mineralogical and textural features differences in textural and mineralogical features are attributed to a updip lateral migration of residual liquid as the sill propagated closer to the surface b deformation caused by tectonic shifts and c crystallization in the presence of deuteric hydrothermal fluids resulting in varying degrees of alteration a model connecting multiple magmatic pulses compaction and mobilization of residual liquid by compositional convection closed system differentiation synchronous with tapping of the sill for extrusion of coeval basaltic subaerial flows is presented the persistence of a low temperature mushy layer represented by ferrogranophyres supports the possibility of a long lived conduit subject to reopening after periods of quiescence in magmatic input leading to the extrusion of the multiple flows of the orange mountain basalt and perhaps even subsequent preakness basalt flows depending on solidification conditions a sub newark basin network of sills subjected to similar protracted input of pulses as hypothesized for the palisades was likely responsible for 600 ka of magmatic activity required to emplace a third set of watchung flood basalts the hook mountain basalt

archaeologically relevant dating techniques for the next century small hot and identified by acronyms abstract this paper presents a brief review of the development and application of dating techniques in addition to radiocarbon which are useful in an archaeological context for hominid evolution these include potassium argon argon argon and fission track dating for dating the emergence of anatomically modern man these include electron spin resonance uranium series amino acid racemization and luminescence dating new approaches are discussed which provide the basis for exciting new applications in the coming decades

petrology geochemistry and diabase granophyre relations of a thick basaltic sill emplaced into wet sediments western montana the plains sill is a thick diabase granophyre body that intruded the wet sediments of the middle proterozoic prichard formation of the belt purcell supergroup the diabase is a high iron tholeiite geochemically compatible with large volume mantle melting in an intracratonic rift environment evidence of emplacement into wet sediments includes thick zones of homogenized granosediments adjacent to the sill soft sediment deformation at sill contacts and sedimentary ovoid structures possibly formed by local fluidization of sediments utilizing sediment pore water and driven by heat from the sill the diabase was metamorphosed during crystallization and cooling leaving hornblende as the dominant mafic phase continued retrograde alteration resulted in overgrowths of secondary hornblende and variable alteration of plagioclase to epidote a miarolitic granophyre layer up to 150 m thick caps the diabase and appears igneous in origin locally the granophyre is anomalously thick perhaps reflecting updip migra

transmission of flood basalts through a shallow crustal sill and the correlation of sill layers with extrusive flows the palisades intrusive system and the basalts of the newark basin new jersey u s a abstractthe palisades intrusive system consists of a 350 m thick early jurassic sill together with thinner comagmatic sills and dikes exposed within the newark basin of new jersey and new york the palisades system is overlain by flood basalt that is interbedded with early jurassic redbed formations new and recently published data indicate that some of the basalt flows correlate with geochemically defined layers within a central well exposed sill portion of the palisades system at fort lee new jersey our interpretation views the sill as a progressively inflated conduit through which huge volumes of flood basalt flowed the geochemical data are consistent with a palisades sill fed by three compositionally distinct intrusion events the first magma flowed through the sill and broke out near the northern end as three orange mountain basalt flows each of the three extrusive pulses is identified within the lower 150 m of the sill on the basis of distinct geochemical reversals the end stage of each pulse w

optical dating in archaeology thirty years in retrospect and grand challenges for the future in 1982 when richard klein first became one of the editors of this journal the luminescence dating community was embarking on a new phase of exploratory research attention was turning from the use of thermoluminescence tl dating to estimate the time of last heating of archaeological objects such as pottery and burnt flint to the tl dating of unheated sediments that had been transported by wind and then deposited on the landscape this revolutionary development enabled the extension of tl dating to sedimentary deposits in a variety of environmental settings and to the multitude of archaeological sites that lack suitably heated artefacts in sediment dating the age of most interest is usually the time elapsed since grains of quartz or feldspar were last exposed to sunlight as the energy of the sun s rays is sufficient to evict electrons from their light sensitive traps these traps are steadily refilled after sediment deposition and the longer the grains remain buried the more tl they will emit when measured in 1985 huntley and colleagues proposed optical dating as a simpler and superior means of stimulating the light sensitive traps in quaternary sediments and this is now the principal luminescence based method of dating geological and archaeological deposits optical dating is an umbrella term for an armada of acronyms the most common in archaeological contexts being osl optically stimulated luminescence tt osl thermally transferred osl irsl infrared stimulated luminescence and pirir post infrared irsl all of these variants are founded on the same basic tenet measurement of a light sensitive signal to determine typically the last time that sediment grains were sun bleached but each approach has its virtues and vices in this paper we review this family of luminescence dating techniques and look back on 30 years of optical dating in archaeology some of the more interesting and important achievements are highlighted including the critical insights gained in the last two decades from osl measurements of individual grains of quartz we also look to the future of optical dating in archaeological contexts efforts to extend the age limits of optical dating to older hominin and archaeological sites will remain a key goal and understanding how archaeological sites of all ages form and evolve over time could be improved greatly by combining micromorphology analysis with optical dating of undisturbed intact sediments the latter poses a series of particularly formidable technical challenges but if the past is any guide to the future then we can expect optical dating to illuminate much more of human history before celebrating its golden jubilee

was the middle wurmian in the high alps warmer than today this study presents a cohesive review of the existing radiometric data as well as morphological and genetic analysis of bear remains from ten high alpine caves mostly from the middle wurmian interstadial complex roughly corresponding to the marine isotope stage mis 3 and dating back between 65 000 30 000 years before present today these caves are located in an area without any vegetation which could not provide the herbivorous bears with sufficient food resources it therefore can be concluded that the middle wurmian in the alps had to be warmer than it is today furthermore congruent and conflicting data from soil formation in loess sequences as well as sinter data in caves are discussed in more detail to evaluate this hypothesis

layered mafic sill complex beneath the eastern snake river plain evidence from cyclic geochemical variations in basalt the eastern snake river plain in southern idaho western united states is characterized by 1 2 km of pleistocene to late pliocene basalt overlying rhyolite caldera complexes cyclic variations in the chemical composition of basalts from 1136 m of scientific drill core show that the parent magmas of these lavas evolved by crystal fractionation at shallow to intermediate crustal depths punctuated by episodic recharge with more primitive compositions and assimilation of adjacent wall rock we have identified 10 upward fractionation cycles and four reversed cycles assimilation of sialic crust was limited and mainly affects the oldest basalts which directly overlie rhyolites we infer that the crystal fractionation and or recharge cycles took place in a series of sill like intrusions at intermediate crustal depths that now form a layered mafic intrusion that underlies the eastern snake river plain at depth this layered sill complex is represented by the 10 km thick basaltic sill that has been imaged seismically at 12 22 km depth the association of this mid crustal sill complex with geochemical fractionation cycles in basalt supports the concept that exposed layered mafic intrusions may be linked to overlying basalt provinces that have since been removed by erosion

luminescence dating applications in geomorphological research abstract chronological control remains critical to the interpretation of environmental change and to establishing long term rates of geomorphological processes radiocarbon dating will continue to be the central technique for age assessment of carbon bearing sediments deposited in the last ca 40 ka but alternative absolute dating strategies are required for older or non carbon bearing sediments they include uranium series dating of precipitated sediments k ar and ar ar dating of primary volcanic materials and cosmogenic isotopic dating of surface exposure ages an additional family of methods collectively termed luminescence techniques is increasingly providing a basis for the age assessment of detrital sedimentary deposits these methods directly date the deposition of detrital mineral grains typically quartz and feldspar and have been demonstrated to provide accurate deposition chronologies for up to 800 ka although 150 ka is more typical in the past decade a subset of luminescence techniques which employ optical sample stimulation methods called optical dating has made it possible to date samples from a much wider range of depositional systems given that the methods directly date sedimentation they allow direct assessment of depositional dynamism in numerous terrestrial and subaqueous including marine sedimentary systems and have demonstrated particular potential in the elucidation of chronologies from aeolian dune and loess fluvial colluvial coastal and volcaniclastic environments this paper provides a summary of the principles of the luminescence especially optical dating methods and shows how recent developments specifically single aliquot dating procedures have dramatically enhanced the scope and potential of the method the luminescence techniques are increasingly being incorporated into a wide range of geomorphological studies which seek to establish the nature of landscape changes over the past interglacial glacial cycle and beyond

the graveyard point intrusion an example of extreme differentiation of snake river plain basalt in a shallow crustal pluton the graveyard point intrusion is the only known example of a wellexposed differentiated mafic pluton associated with the late miocene pleistocene magmatism of the western snake river plain srp it is exposed in a 6 km by 4 km area adjacent to the oregon idaho border and exposures range in thickness from 20 to 160 m the thicker parts of the intrusion are strongly differentiated and contain a 25 60 m thick section of well laminated cumulus textured gabbros that grade upward into pegmatoidal ferrogabbro evolved liquids formed sheets of fe rich siliceous granophyre at least two injections of magma are indicated by abrupt discontinuities in the rock and mineral compositions and by the lack of mass balance between the bulk intrusion and its chilled borders the laminated gabbros are interpreted to have formed from a tongue of augite and plagioclase crystals that were carried in with the second pulse of magma following the final emplacement of the intrusion in situ differentiation proceeded through a two stage process the ferrogabbros are explained as interstitial liquids forced out of the crystal mush by compaction and the siliceous granophyres are interpreted to be residual liquids that migrated out of the partly crystallized ferrogabbros in response to the exsolution of volatiles because the geochemical trend inferred for the mafic to intermediate composition liquids in the graveyard point intrusion is similar to the trend for many western snake river plain lavas the pluton may be a good model for shallow sub volcanic magma chambers elsewhere in the srp however some western srp lavas contain anomalously high concentrations of p2o5 which are best explained by mixing within the active crustal mush column or with partial melts of previously formed differentiated mafic intrusions

the role of residual melt migration in producing compositional diversity in a suite of granitic rocks abstract we present a quantitative model for in situ crystallization within a solidification zone or boundary layer based on the trace and major element compositions of plutonic igneous rocks and related geochemical data we developed the model to account for the characteristics of a suite of granitic rocks nearly uniform mineral compositions in rocks that range widely in bulk composition e g 58 76 wt sio 2 linear variation and correlation of all major and trace elements analyzed except ba large and apparently random variations in ba concentration these characteristics cannot be explained by any standard petrogenetic model involving fractionation mixing or restite unmixing but are successfully reproduced by our model of residual melt migration we do not attempt to model the entire crystallization history of a pluton but rather only that interval during which melt migration processes have recognizable geochemical effects for the granitic suite the chemical signature of residual melt migration resulted from the change in ba compatibility with the onset of orthoclase crystallization at a granite minimum our results demonstrate that plutonic rocks can develop large compositional variations comparable to those expected to result from extreme differentiation within a large magma body over short distances by melt migration under conditions of high permeability or slow crystallization rate within the solidification zone melt migration is probably a common process that could be overlooked in large plutons if sampling is sparse and if variations in some components that appear random are not considered our model equations yield estimates for parameters that describe the proportions of residual melt that crystallize within and migrate out of the solidification zone values of these parameters can be used to infer information about permeability and melt mobility within the solidification zone the model parameters derived for the granitic suite have a roughly concentric spatial pattern in the pluton suggesting that residual melt was trapped near the margins accumulated in the interior with a zone of enhanced melt mobility and possibly compositional convection in between our model may be of general usefulness because it requires no assumptions about magma chamber geometry or magma dynamics it is applicable to magmas of any composition and the equations could be formulated to include those variables best constrained by a particular suite of plutonic igneous rocks

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

the cumulate paradigm reconsidered the cumulate terminology outlined by wager and coworkers provided a logical system for describing the textures of the rocks of layered intrusions but recent work shows that this model fails to accommodate all the processes responsible for the petrographic features of coarse grained rocks textures of adcumulates and orthocumulates in the skaergaard intrusion cannot be correlated with concentrations of incompatible elements representing trapped liquid compaction and open system percolative processes have altered their textures modes and even bulk compositions although a rock may be a cumulate in the absence of other evidence it can be misleading to refer to it in terms of the cumulate nomenclature

the origin of basic ultrabasic sills with s d and i shaped compositional profiles by in situ crystallization of a single input of phenocryst poor parental magma an attempt is made to develop an in situ crystallization model based on the concept of soret fractionation to explain the origin of commonly observed s d and i shaped compositional profiles in sills formed from a single pulse of phenocryst poor parental magma the model envisages that the various compositional profiles observed in sills can be interpreted in terms of different combinations of four principal units basal zone and layered series forming the floor sequence and top zone and upper border series constituting the roof sequence the basal and top zones represent mirror images of the layered and upper border series respectively and therefore are referred to as basal and top reversals it is proposed that the formation of basal and top reversals takes place through the non equilibrium soret differentiation of liquid boundary layers which form as a consequence of the temperature gradient imposed by the cold country rock in contrast the layered and upper border series originate predominantly through the crystal liquid boundary layers developing in equilibrium conditions the model permits the production of s d and i shaped compositional profiles from the same magma composition all that is necessary to produce a specific shape of compositional profile is an appropriate temperature gradient imposed by the cold country rock on the liquid boundary layers of a parental magma of a given composition

what attributes are important for the measurement of assemblage reduction intensity results from an experimental stone artefact assemblage with relevance to the hoabinhian of mainland southeast asia abstract our understanding of variation in the technology of flaked stone artefacts from mainland southeast asia during the terminal pleistocene and holocene periods has improved little since they were originally labelled hoabinhian in 1932 chronological and geographical variation has been described in terms of typological differences but there are few anthropological explanations of lithic diversity and change an analysis of an experimentally produced hoabinhian assemblage is undertaken here to show which flake variables are significant indicators of assemblage reduction intensity the results show that recording the presence of overhang removal interior platform angle and percentage of dorsal cortex will provide robust data on the extent of assemblage reduction a new method for detecting assemblage variation based on the location of dorsal cortex on flakes is also presented and experimentally verified these methods are designed to take advantage of the typical geometry and reduction patterns of hoabinhian assemblages these findings provide another tool to build anthropological explanations of hoabinhian archaeology

palisades sill origin of the olivine zone by separate magmatic injection rather than gravity settling the still widely cited view of the palisades sill northeastern united states being differentiated largely by vertically directed olivine dominated fractionation is not supported by available structural petrographic and geochemical data rather the sill can be viewed as a sheetlike composite intrusion possibly made up of multiple magma types common to the mesozoic eastern north america magmatic province the famous olivine zone of the palisades sill may have resulted from a separate late intrusion of olivine normative magma and not from gravity controlled olivine accumulation processes pyroxene dominated fractionation accounts for much of the vertical and lateral compositional variations in the palisades sill and other related intrusions from the province

middle pleistocene hominin occupation in the danjiangkou reservoir region central china studies of formation processes and stone technology of maling 2a site abstract danjiangkou reservoir region drr is one of the areas where acheulean like stone technology mode 2 was reported in central and south china it is located at the end of the upper reaches of the hanshui river the largest tributary of the yangtze river systematic field investigations documented more than ninety paleolithic sites along the fluvial terraces of the hanshui and danjiang rivers the latter a tributary of the upper reach of the hanshui river subsequent excavations at more than 30 sites led to the discovery of a large number of paleolithic stone artifacts in the past decade showing that early hominins lived in the region at least by the early part of the middle pleistocene however little is known from the archaeological record about the context of the sites and their formation processes the technological characteristics of the stone artifact assemblages and whether they truly belong to mode 2 technology or just to core and flake technology and the overall hominin behavioral patterns and adaptation during the middle to late pleistocene maling locality 2a ml2a is buried in the front edge of the third alluvial terrace of the danjiang river archaeological excavations undertaken at the site in 2011 recovered 1026 stone artifacts from a red clay deposit preliminary osl dating and geomorphological comparisons between the terraces in the hanshui river system suggest that the site is dated to the late middle pleistocene patterns of artifact concentration suggest that the site was buried in secondary context where the stone artifacts were transported by water from a relatively higher location nearby the artifacts primarily made on quartzite and quartz cobbles include cores whole flakes various fragments retouched pieces two bifaces and a hammerstone all flaking is by direct hard hammer without core preparation the majority of flakes in the early stages of core reduction indicate that the cores are not extensively reduced choppers are the predominant core category together with discoids polyhedrons and core scrapers it should be noted that two bifacially flaked cobbles can classed as mode 2 implements eleven retouched pieces are recognized and they were casually modified by direct hammer percussion although only two bifaces were excavated from this site many more are recorded in the larger study area the ml2a artifact assemblage may be considered as a chinese variant of an acheulean like mode 2 industry it can be deduced that homo erectus was likely the responsible for manufacturing the stone artifacts

thermal ionization mass spectrometry u series dating of a hominid site near nanjing china mass spectrometric u series dating of speleothems from tangshan cave combined with ecological and paleoclimatic evidence indicates that nanjing man a typical homo erectus morphologically correlated with peking man at zhoukoudian should be at least 580 k y old or more likely lived during the glacial oxygen isotope stage 16 similar to 620 ka such an age estimate which is similar to 270 ka older than previous electron spin resonance and alpha counting u series dates has significant implications for the evolution of asian h erectus dentine and enamel samples from the coexisting fossil layer yield significantly younger apparent ages that of the enamel sample being only less than one fourth of the minimum age of nanjing man this suggests that u uptake history is far more complex than existing models can handle as a result great care must be taken in the interpretation of electron spin resonance and u series dates of fossil teeth

hydrochemistry and quality of groundwater in alluvial aquifer of karonga malawi this study highlights the quality of groundwater for both drinking and irrigation in karonga north where subsistence and commercial farming is practiced all major groundwater quality descriptors and selected trace elements iron manganese arsenic and aluminum were studied the study demonstrated evidence of higher concentrations of bicarbonates 60 590 mg l total iron 2 2 5336 g l total manganese 0 1 804 g l and total arsenic 0 4 14 5 g l in certain samples with low values of eh 32 0 to 25 8 and no3 8 2 mg l against who standards thirty six percent of samples were rated as poor using the water quality index wqi criteria no scaling potential was observed using the langelier analysis the majority of samples were of the mixed bicarbonate type with the abundance order of cations as ca2 na mg2 k carbonate dissolution silicate weathering and cation exchange were identified as possible main geochemical control mechanisms the sources responsible for fluoride and nitrate include anthropogenic activities and rock water interaction dissolution precipitation and ph control the levels of as fe and mn

approaches to middle stone age landscape archaeology in tropical africa the southern montane forest grassland mosaic ecosystem in the humid subtropics southern rift valley of africa comprised the environmental context for a large area in which modern human evolution and dispersal occurred variable climatic conditions during the late pleistocene have ranged between humid and hyperarid changing the character of the ecosystem and transforming it at different points in time into a barrier a refuge and a corridor between southern and eastern african populations alluvial fans presently blanket the areas adjacent to major river systems which were key areas of prehistoric human habitation these sets of variables have created conditions that are both challenging and advantageous to conduct archaeological research lateritic soil development has resulted in poor organic preservation and facilitated insect bioturbation which has demanded an integrated micro macro scale approach to building a reliable geochronology an integrated field and analytical methodology has also been employed to identify the nature and degree of post depositional movement in alluvial deposits which preserve a wide range of spatial integrity levels in buried stone artifact assemblages between 47 and 30 ka in karonga northern malawi this paper describes the methodological advances taken toward understanding open air middle stone age archaeology in sub tropical africa and explores the inferential potential for understanding pleistocene human ecology in the important southern rift valley region

oldowan reduction sequences methodological considerations abstract transport of resources is a major feature of oldowan hominin technological adaptations comparisons between different oldowan localities often employ measures of transport that are based on artefact attributes as proxies for the intensity of raw material utilization the technological flake category system toth n 1985 oldowan reassessed a close look at early stone artifacts journal of archaeological science 12 pp 101 120 has been used extensively to infer the relative intensity of lithic reduction within oldowan assemblages here we use a large experimental sample to test the relationship between a flake s stage in a reduction sequence and various quantitative attributes we demonstrate how many previously described attributes are affected by initial core size we then develop a multiple linear regression model that incorporates several variables to predict the placement of a flake within a generalized reduction sequence the model is then applied to oldowan assemblages in the koobi fora formation which explores the strengths and weaknesses of different methods of investigating reduction intensity on an assemblage level

multiple reinjections and crystal mush compaction in the beacon sill mcmurdo dry valleys antarctica the beacon sill a member of the jurassic ferrar group of the transantarctic mountains south victoria land is a 150 m thick tholeiitic diabase intrusion uniform on a field and macroscopic scale it displays chemical and textural variability indicative of a sustained and complex history of emplacement and differentiation emplacement of the sill consisted of at least two and probably four discrete massive injections of magma each averaging 35 m thick over a time span of 100 years the final injection event is marked by a 30 m thick interval of significantly finer grained rock at the sill center these fine grained textures can be successfully reproduced by combining the results of thermal and crystal growth models but only if the sill was a multiple intrusion with the exception of a minor reinjection event captured in the chilled margin of the sill earlier reinjection events are not evident texturally most probably because of textural overprinting during prolonged cooling after initial crystallization the dominant process involved in the postemplacement differentiation of the beacon sill was compactiondriven redistribution of interstitial liquid transfer of residual liquid from the compacting lower solidification front to the dilating upper solidification front resulted in characteristic chemical and mineralogical effects such as the depletion of the lower half of the sill and the enrichment of the upper half of the sill in incompatible elements e g tio2 zr and modal granophyre based on thermodynamic models most of the compaction occurred at a crystallinity of roughly 33 geochemical profiles are distinctly segmented suggesting that the sill was repeatedly split and reinjected with fresh magma near the center after compaction had redistributed the interstitial liquid within the partially solidified magma the recognition of evidence for reinjection and compaction in a macroscopically uniform relatively quickly cooled sill suggests that these processes may be common in the construction of sills and other mesoscale igneous intrusions in general

a felsic end to bushveld differentiation the similarities in age c 2 06 ga and isotopic composition of the bushveld igneous complex and the overlying rooiberg group felsic volcanic rocks suggest the possibility that the two are cogenetic to investigate this possibility we derive a robust new estimate of the major and trace element bulk composition of the bushveld upper zone and upper main zone uumz using melts thermodynamic modeling we show that this composition fails to reproduce fundamental features of the cumulate sequence such as the presence of primary orthopyroxene at the base of the magma column we investigate the possibility that some amount of evolved magma escaped from the magma chamber and derive a new estimate of the uumz parent magma composition that reproduces generally the observed cumulate sequence our results constrain the amount and composition of the escaped magma and provide evidence of a genetic link between the uumz of the bushveld layered series and the felsic volcanic rocks immediately overlying it we conclude that between 15 and 25 of the original magma volume was expelled and is manifest either as part of the upper rooiberg group lava sequence or the rashoop granophyre distinction is hindered by their almost identical major and trace element compositions a parent magma in which 15 25 rooiberg or rashoop material is added back to the extant cumulate sequence is initially saturated in orthopyroxene and is in major and trace element equilibrium with the phases at the base of the uumz

middle stone age archaeology at olduvai gorge tanzania abstract this paper describes the motivation procedures and results of archaeological and geological field survey of the ndutu unit olduvai gorge conducted in june and july of 2013 survey focused upon the area of olduvai gorge between the second fault and the obalbal depression although selective survey occurred in other areas in and around the gorge over 72 archaeological find spots were recorded and hundreds of middle stone age msa artifacts were recovered as was a small sample of fauna geological observations provisionally suggest that the ndutu was formed in part from a series of pyroclastic density flow and ash fallout events from neighbouring volcanoes this contrasts slightly with previous interpretations of the deposits in that at least some of the beds are thought to be in primary stratigraphic context our initial field findings are conducive to discussions of a number of issues directly relevant to the msa in east africa and overall we conclude that there is strong potential for olduvai s ndutu unit to shed light on the behavior adaptations and evolution of homo sapiens prior to during and just after its physical emergence