the abrasion of modern and archaeological bones by mobile sediments the importance of transport modes abstract fresh weathered archaeological and fossilized bones were subjected to a series of abrasion experiments using fine sand in an annular flume in order to link bone surface abrasion to flow regimes and sediment transport modes compare these effects on bones of different states and quantify the extent and types of wear occurring flow velocities were chosen to replicate the predominant transport modes of bedload saltation and suspension comparative scanning electron microscopic image analysis was performed to assess the degree and type of wear occurring on each bone type for the different transport modes over a range of exposure periods from 24 to 72 h these preliminary investigations have shown that both the amount and type of wear experienced was related to the bone type duration of exposure and the mode of sediment transport with wear being the result of deformation rather than cutting wear the formation of scour pits in the sand bed on the upstream side of the bone samples significantly reduced wear and appears to be an important control mechanism for impact related wear that has been overlooked until now

an outsider s review of the astronomical theory of the climate is the eccentricity driven insolation the main driver of the ice ages abstract although the astronomical theory of the climate also known as the milankovitch theory explains a number of key features of the paleoclimate time series especially frequency and phase distribution in terms of orbital influence on the waxing and waning of ice sheets it still faces several important unresolved challenges in this review we discuss five main challenges we believe the theory must resolve in order to survive 1 the large amplitude of the 100 ky ice age cycles 2 the switch from 41 ky to 100 ky long glaciations around 0 9 ma bp 3 the absence of significant spectral power at 413 ky over the past 1 2 ma 4 the variation in glacial cycle duration in the last 800 ky and 5 the presence of non orbital spectral peaks in the climate record but in spite of these problems we conclude that the milankovitch theory may still be a viable one at least in the original sense of hays et al science 194 1976 1121 that orbital changes somehow influenced the ice ages many investigators ourselves included appear to see the impact of orbital forcing in the data clear evidence of astronomical forcing as well as evidence which suggests that the climate system responds nonlinearly to all milankovitch orbital frequencies

astronomically controlled cycles in the lower tertiary of gubbio italy abstract a grouping of marl limestone beds in the tertiary of gubbio is interpreted in terms of sedimentary cycles two methods of recording are used subjective mapping of cycle boundaries in the field and power spectral analysis of bed thickness measurements both result in cycle thicknesses of between 30 and 70 cm the cycle record is compared with the known magnetic stratigraphy and this gives an absolute time estimate of 100 kyr for the cycle it therefore seems likely that the earth s eccentricity period is the ultimate cause of the cycle

processes dominating macro fabric generation in periglacial colluvium abstract mass wasting processes in a periglacial environment are considered to result from a combination of frost creep and gelifluction the relative importance of these processes is often difficult to determine but appears to be related to factors such as slope angle soil moisture content soil texture and vegetation cover further the importance of any one of these factors can vary from year to year thereby making long term predictions of slope stability or reconstructions of behaviour history difficult this study uses two dimensional macro fabric analysis as a recorder of the dominant mode of mass wasting on a slope clast trend and plunge data were collected from 68 sites at eagle summit alaska and examined in two separate dimensions the plane of the slope to represent the stress field driven by gravity and in a vertical plane trending down the slope to represent the stress field created by frost heaving pressures circular correlation tests indicate the importance of the downslope stress field on clast position in the plane of the slope in the vertical plane clast plunge varies according to slope on gentle slopes clasts tend to be steeply dipping on moderate slopes they are parallel to the plane of the slope and on steep slopes they are imbricated these observations correspond to modeled experiments of slope deformation under periglacial conditions and suggest that at the scale of the slope mass wasting processes are influenced by varying intensities of frost heave and gravity transfer that are conditioned by slope angle

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

beyond maps patterns of formation processes at the middle pleistocene open air site of marathousa 1 megalopolis basin greece abstract recent excavations at the middle pleistocene open air site of marathousa 1 have unearthed in one of the two investigated areas area a a partial skeleton of a single individual of palaeoloxodon antiquus and other faunal remains in spatial and stratigraphic association with lithic artefacts in area b a much higher number of lithic artefacts was collected spatially and stratigraphically associated also with faunal remains the two areas are stratigraphically correlated the main fossiliferous layers representing an en mass depositional process in a lake margin context evidence of butchering cut marks has been identified on bones of the elephant skeleton as well on elephant and other mammal bones from area b however due to the secondary deposition of the main find bearing units it is of primary importance to evaluate the degree and reliability of the spatial association of the lithic artefacts with the faunal remains indeed spatial association does not necessarily imply causation since natural syn and post depositional processes may equally produce spatial association assessing the degree and extent of post depositional reworking processes is crucial to fully comprehend the archaeological record and therefore to reliably interpret past human behaviours the present study uses a comprehensive set of spatial statistics in order to disentangle the depositional processes behind the distribution of the archaeological and palaeontological record at marathousa 1 preliminary results of our analyses suggest that a high energy erosional process attributed to a hyperconcentrated flow deposited at the margin of a swamp reworked an autochthonous exposed or slightly buried scatter of lithic artefacts and faunal remains minor reworking and substantial spatial association of the lithic and faunal assemblages support the current interpretation of marathousa 1 as a butchering site

on the possible influence of extraterrestrial volatiles on earth s climate and the origin of the oceans abstract a consideration of observational and circumstantial evidence suggests that earth may be subject to high influx rates 1011 1012 kg yr of extraterrestrial sourced volatile elements carbon hydrogen oxygen nitrogen derived from comets or other primitive solar system material the total extraterrestrial influx rate may be four to five orders of magnitude greater than previously thought large enough to account for today s total near surface inventories of water and carbon the possibility of high rates of extraterrestrial volatile accretion suggests a new climatic paradigm wherein earth s surface temperature is influenced by conflicting internal and external processes a variable influx of volatile elements tends to warm the earth while terrestrial processes cool the planet by absorbing these gasses at a more uniform rate variations in extraterrestrial influx rates may explain the variation of sea level and mean global temperature over geologic time as well as some types of climate change the occurrence of the pleistocene ice ages and the asymmetry of the phanerozoic climate record sudden warmings slow coolings the extraterrestrial influx rate may also act as the pacemaker of terrestrial evolution at times leading to mass extinctions through climatic shifts induced by changes in accretion rates with concomitant disruptions of the carbon and nitrogen cycles life on earth may be balanced precariously between cosmic processes which deliver an intermittent stream of life sustaining volatiles from the outer solar system or beyond and biological and tectonic processes which remove these same volatiles from the atmosphere by sequestering water and carbon in the crust and mantle

chemical sedimentology and paleoenvironmental history of lake olduvai a pliocene lake in northern tanzania lake olduvai was a saline highly alkaline closed basin lake in which lacustrine sediments of bed i and lower bed ii of olduvai gorge were deposited between ca 1 92 and 1 70 ma the lake consisted of a lacustrine area the central basin cb surrounded by lake margin terrain that was alternately flooded and dried the lacustrine deposits consist largely of authigenic clay and carbonate minerals zeolites k feldspar chert and pyrite claystones of the cb and most of the eastern lake margin elm terrain consist chiefly of mg rich authigenic illite smectite and interlayered illite smectite i s these clays were formed penecontemporaneously with detrital clay deposition by interaction of the detrital clays with the saline highly alkaline water the lake olduvai clays average 65 70 mg 2 sio 2 and alkali ions from lake water and the remaining 30 35 is detrital clay lacustrine clays of the elm indicate that this area was flooded by saline water for substantial periods of time hominids occupied the elm at times of lower lake levels when the clays were dried calcite is the most abundant carbonate mineral and occurs chiefly as sand size euhedral crystals dispersed in claystone and less commonly as calcite crystal limestones and nodules the sand size calcite crystals were formed diagenetically at shallow depths possibly from a gaylussite and or micritic calcium carbonate precursor dolomite occurs chiefly in the form of dolostones some of which are probably of replacement origin the oxygen isotope composition of lake water and pore fluid of the cb varied over 11 as determined from calculated delta 18 o h 2 o values of authigenic minerals clay minerals were formed chiefly in the more saline waters sand size calcite crystals were generated mostly from less saline pore fluids and limestone nodules were formed chiefly from dilute pore fluid dolostones were formed from fluids of varying salinity hydrogeology of the central basin was complex and postdepositional fluid movements are documented by differing delta 18 o h 2 o values for different authigenic minerals of the same samples pore fluids moved within the lake deposits for a considerable period of time after deposition as shown by 18 o values of quartz and k feldspar formed at different times downward flow of lacustrine fluids is indicated by zeolitic alteration of the underlying tuffaceous alluvial deposits lake olduvai became overall shallower during the deposition of bed i and the subaerial exposure increased leading to occasional playa conditions these changes very likely resulted from increasing aridity and tectonic activity the lake that deposited lower bed ii was larger than that responsible for upper bed i and episodes of wetter climate alternated with drier periods in which salinity and probably temperatures were higher than in the bed i lake

a spring and wooded habitat at flk zinj and their relevance to origins of human behavior the 1959 discovery of the hominin fossil zinjanthropus boisei brought the world s attention to the rich records at olduvai gorge tanzania subsequent excavations of archaeological level 22 flk zinj bed i uncovered remains of homo habilis and a high density collection of fossils and oldowan stone tools the occurrence of this unusual collection of bones and tools at this specific location has been controversial for decades we present paleoecological data that provide new insights into the origin of flk zinj our recent excavations 200 m north of the site uncovered a 0 5 m thick tufa mound draped by tuff ic in the same stratigraphic horizon as level 22 stable isotope analyses indicate that the carbonates were deposited by a freshwater spring phytolith analysis of the waxy clay under tuff ic revealed abundant woody dicotyledon and palm phytoliths indicating that the site was wooded to densely wooded the time equivalency and close physical proximity of the two environments indicate the two are related this study has provided the first documented evidence of springs in bed i and these data have important implications for the interpretation of hominin behavior in meat acquisition and the ongoing debate on scavenging versus hunting

influence of orbital parameters on pleistocene loess deposition in central alaska few long proxy climatic records are available from terrestrial locations the isotope records of pleistocene climate change found in marine cores reflect worldwide ice volume and temperature changes forced by variations in the earth s orbital geometry comparable terrestrial records are rare loess wind deposited silt is perhaps the closest terrestrial analogue to marine sediments in that both result from more or less continuous deposition of fine grained sediment here we examine the hypothesis that mag netic susceptibility variations through loess sections reflect climate forcing we statistically tested cross correlations between high precision orbitally tuned marine oxygen isotope curves recording the past 250 000 yr bp and magnetic susceptibility profiles through a thick loess section in central alaska highly significant p 0 0001 correlations indicate strong thick palaeosols formed in arctic loess during early parts of interglacial periods correspond ing to isotope stages 7 and 5 thinner soils formed during interstadial events corresponding to early stage 7 and stage 3 autocorrelation and time series analysis of the loess data show spectral peaks at 125 000 41 000 and 23 000 yr bp showing for the first time that terrestrial orbital periodicities influenced and are recorded in proxy climatic data from terrestrial aeolian deposits at high latitudes

paleomagnetism and geochronology of the ecstall pluton in the coast mountains of british columbia evidence for local deformation rather than large scale transport 1 samples for geochronologic geobarometric and paleomagnetic analyses were collected across the northern portion of the ecstall pluton southeast of prince rupert british columbia al in hornblende geobarometry indicates pressures from 740 10 to 840 30 mpa corresponding to crystallization depths of 25 to 30 km u pb analyses of zircons from western central and eastern localities within the pluton yield crystallization ages of 91 5 1 0 ma 90 8 1 0 ma and 90 5 1 0 ma respectively rock magnetic experiments reflected light microscopy and thermal demagnetization behavior suggest that natural remanent magnetism is carried by low ti titanohematite unblocking temperatures of the characteristic remanent magnetization chrm are dominantly in the 560 c to 630 c range with age of magnetization approximated by the 40ar 39ar hornblende ages of 84 2 0 10 ma on the western margin and 76 4 0 6 ma in the center of the pluton site mean chrm directions were isolated for paleomagnetic samples from 23 sites and are distributed along a small circle with subhorizontal axis at 340 azimuth chrm directions from the central portion of the pluton are concordant with the expected cretaceous magnetic field direction while chrm directions from the western margin are discordant by 70 folding of the ecstall pluton either during late cretaceous west directed thrust transport above the convex upward prince rupert shear zone or during younger deformation of the pluton and underlying shear zone can account for the paleomagnetic data and is consistent with the geochronologic geobarometric and structural geologic observations

new excavations at the flk zinjanthropus site and its surrounding landscape and their behavioral implications renewed excavations at flk zinj and its surrounding landscape have yielded valuable information regarding its paleoecological situation and the prehistoric behavioral function of the site the density of materials at the main cluster of the site excavated by leakey contrasts with the bone and lithic scatters surrounding the site the location of flk zinj situated a few hundred meters away from a freshwater spring would have enabled hominins access to water plants and game the appeal of the spot for hominins also explained by the presence of a wooded habitat is confirmed by inferences of its redundant use prior and during the formation of the flk zinj paleosol as witnessed by materials accumulated both under and on the waxy clay deposit that constitutes the flk zinj stratum the single cluster nature of the site indicates central place behavior and evidence is provided that hominins occupied the site at a time of very low predation hazards in the area

orbital cyclicities above and below the cretaceous paleogene boundary at zumaya n spain agost and relleu se spain abstract the rhythmicity of hemipelagic limestone marl successions covering the cretaceous paleogene k pg boundary is investigated and evidence of orbital control is presented three sections were surveyed and sampled in detail two are located near agost and relleu in the province of alicante and one near zumaya in the basque country the distance between agost and relleu is about 30 km between agost and zumaya about 600 km the carbonate content of 2779 samples was determined and used as a proxy to determine cyclicities lithologically all three successions are very similar although in the maastrichtian of the zumaya succession 63 7 m 339 light green siliciclastic turbidite layers varying in thickness between 0 1 and 12 cm intercalate with the calcisiltites conventional paleomagnetic and micropaleontologic datum planes are few and show the usual associated uncertainties power spectra based on the few reliable datum planes available are unstable more datum planes were created in an unconventional way i e by visual correlation of the local maxima and minima of the carbonate curves to those of the relevant part of the theoretical eccentricity curve the validity of the method is based on the assumption that the eccentricity periods are considered practically stable throughout geologic time the results support the hypothesis that the carbonate rhythmicity at agost relleu and zumaya are orbitally controlled most likely orbital forcing and random processes play a role in the frequency of occurrence and the thickness of turbidites in the maastrichtian of zumaya the age of the k pg boundary is estimated at 64 56 0 4 ma

autochthonous anisotropy of archaeological materials by the action of water experimental and archaeological reassessment of the orientation patterns at the olduvai sites abstract anisotropic patterns documented indirectly through m leakey s drawings of olduvai archaeological sites have led to questions about the integrity of these sites most experiments on bone transport by water have been carried out using complete elements that do not replicate specimen bone breakage and size as documented in archaeological sites in the present work an experimental framework is provided using experimental proxies of archaeological assemblages results show that autochthonous assemblages affected by hydraulic processes can adopt anisotropy in their fabric archaeological comparisons between drawings and excavated sites at olduvai stress the bias in leakey s drawings of flk zinj and flk north in bed i a large scale open excavation recently carried out at tk bed ii exposes an area comparable in size to leakey s excavations comparing the orientation patterns of this site to those reported by leakey shows how biased the drawing of the site is and how easily this can lead to misinterpretations of isotropy anisotropy with fatal consequences for the understanding of site formation processes

a bimodal volcanic plutonic system the zarembo island extrusive suite and the burnett inlet intrusive complex the zarembo island volcanic rocks and the burnett inlet plutonic complex in central southeastern alaska were investigated to determine if they are genetically related the zarembo island volcanic suite consists of basalt andesite and rhyolite lava flows which exhibit features that suggest simultaneous eruptions of mafic and felsic lavas five kilometres to the southeast the broadly layered burnett inlet plutonic complex consists of gabbro diorite and granite plutons that also show characteristics of contemporaneous mafic and felsic magmatism these bimodal volcanic and plutonic rocks are similar in age ranging from 18 5 to 21 5 ma both suites show a gap in silica concentration between 60 and 65 wt and have similar major trace and rare earth element composition both suites also show igneous layering either as interlayered basalt and rhyolite flows or as alternating gabbro and granite sheets additionally both groups contain magma mingling and mixing textures including mafic enclaves in felsic members and quartz xenocrysts rimmed by clinopyroxene in enclaves these characteristics suggest that the burnett inlet intrusive complex and the zarembo island volcanic suite represent an eroded shallow level plutonic center and its eruptive cover the style of volcanism and the bimodal nature of magmatism suggest that igneous activity occurred during crustal extension and thinning that accompanied strike slip tectonic motion in southeastern alaska during the tertiary the volcanic plutonic rock associations now exposed at the surface indicate that at least 7 of post 20 ma crustal tilting has affected the region and can help to explain aberrant paleomagnetic poles in mid cretaceous intrusions of the cordillera coast belt

the river that never was fluvial taphonomy at olduvai bed i and ii sites and its bearing on early human behavior olduvai site integrity has been questioned through interpretations of fluvial inputs on most assemblages from beds i and ii that rest on a contradictory use of taphonomic variables lack of geological support and lack of adequate experimentally supported referential frameworks most variables used to address fluvial impact in faunal assemblages have been independently used in other contexts and all of them are subjected to variable degrees of equifinality their resolution when applied to archaeological assemblages is low a more recent approach founded on experimentation simulating actual archaeological sites shows that it is the intrinsic properties of each bone specimen i e composition and shape that best determine the resistance of each bone to be moved by water regardless of size the application of this approach which combines the relative representation of specimens according to their composition i e texture dense or spongy trabecular or mixed and shape flat tube or cube polyhedral shows not only that fluvial inputs on bone assemblages can be well detected but also that the scale and magnitude of such inputs can be efficiently assessed thus site formation can be more accurately interpreted with the aid of these new experimental analogical frameworks a selection of some of the most relevant olduvai sites from bed i and bed ii have been used to show that all represent autochthonous concentrations of fossil materials and that their potential fluvially caused distortion was marginal in most sites and moderate in the form of semi lag assemblages in just a couple of them this reinforces the causality of biotic agents i e hominins and carnivores in the formation of these sites

combined quantification of anisotropy and inhomogeneity of magmatic rock fabrics an outcrop scale analysis recorded in high resolution abstract magmatic mineral distribution patterns in a syntectonic syenite pluton have been recorded at high resolution over several square metres on quarried faces the anisotropy and inhomogeneity of k feldspar and mafic mineral distribution patterns have been quantified using two methods originally based on fractal geometry 1 map counting based on box counting illustrates an inhomogeneity on the decimetre to metre scale and highlights diffuse structures that can be related to mafic schlieren or felsic dykes that are not visible on the rock surface 2 we have developed a mapping of rock fabric anisotropy morfa method that leads to the detection of further magmatic structures that are not visible in the field with morfa a magmatic lineation and its variation over large areas is determined as well as fabrics on the decimetre to 1 m scales which possibly represent flow or fracture structures in the crystallising magma

orientation patterns of wildebeest bones on the lake masek floodplain serengeti tanzania and their relevance to interpret anisotropy in the olduvai lacustrine floodplain abstract a study of bone orientation patterns at a wildebeest bonebed deposited in the floodplain of lake masek tanzania shows that portions of the assemblage exhibit anisotropy probably caused by the combined action of lake transgression and regression and the watersheet formed during the rainy season which is also responsible for a large part of the microtopographical features of the surface where the bonebed was formed some taphonomic indicators absence of polished or abraded bone similar representation of voorhies anatomical groups i and iii show that the anisotropic trend was formed under very low energy conditions anisotropy can be locally produced in autochthonous assemblages bone orientation patterns need to be combined with other taphonomic techniques to determine the depositional nature of any given assemblage

extraterrestrial 3he in seafloor sediments evidence for correlated 100 kyr periodicity in the accretion rate of interplanetary dust orbital parameters and quaternary climate we have determined the helium abundance and isotopic composition of seafloor carbonate sediments from the flanks of the ontong java plateau western equatorial pacific ocean odp site 806 these results provide a two million year record of the burial flux of extraterrestrial 3he which we believe is a proxy for the terrestrial accretion rate of interplanetary dust particles the 3he burial flux prior to 700 ka was relatively low 0 5 pcc cm 2 kyr 1 but from 700 ka to the present the burial flux gradually increased to a value of 1 0 pcc cm 2 kyr 1 100 kyr periodicity in the 3he burial flux is apparent over the last 700 kyr and correlates with the oxygen isotope record of global climate with high 3he burial fluxes associated with interglacial periods this periodicity and phase are consistent with previous 3he measurements in north atlantic sediments although 100 kyr periodicity in 3he burial flux is in agreement with recent predictions of the accretion rate of interplanetary dust based on a model of the orbital evolution of asteroidal debris the measurements and predictions differ by one half cycle in phase nevertheless our observations suggest the terrestrial accretion rate of interplanetary dust is controlled by orbital eccentricity and or inclination relative to the solar system invariable plane such control is a necessary but not sufficient condition for the hypothesis of muller and macdonald 1995 that variations in extraterrestrial dust accretion modulates terrestrial climate with a 100 kyr period we also identify several brief 25 kyr intervals of strongly enhanced 3he burial possibly related to random and transient fluctuations in the accretion rate of asteroidal or cometary dust particles

taphonomy of some articulated skeletal remains transport potential in an artificial environment flume experiments demonstrated that disarticulated bones did not display the same behaviour when combined as articulated elements the character of movement and rates of movement were recorded skeletal elements were identified as displaying either a transportable or a non transportable potential some of which were common to all three species that were tested the experiments demonstrated that articulated bones displayed a greater transport potential and that in one species the rate of movement was significantly faster than when disarticulated it is suggested that the taphonomic history of a fluvial transported assemblage could be misinterpreted if the bones were treated as a mixture of individually transported elements

mineral assemblages and low energy sedimentary processes in the flk zinj ds ptk and amk complex palaeolandscape olduvai gorge tanzania the mineralogical composition of the clay stratum level 22 that contains the flk zinj ds ptk amk complex the only example of pene contemporaneous early pleistocene sites occurring on the same palaeolandscape and simultaneously covered by the same ash fall tuff shows significant intra site and inter site differences overall level 22a is related to a more hydrologically closed system with higher salinity and alkalinity than level 22b both levels show fresher water was entering the system from the ds area during deposition textural analysis of the studied samples shows great microporosity and abundant edge to edge and edge to face contacts between crystals these results have major repercussions for the interpretation of the archaeological assemblages in the flk zinj ds ptk amk palaeolandscape first this implies that two distinct archaeological levels formed at different times with different environmental conditions in most of these localities second textural analyses provide evidence that no important sedimentary compaction took place after the deposition of this layer this affects interpretations of palaeolandscape geomorphology third it shows that the sedimentary processes during all the clay sequence occurred in very low energy conditions this reinforces that no significant physical forces disturbed the original configurations of materials contained within these assemblages and reinforces their autochthony behavioural interpretations can thus be more solidly built upon the conception that those sites preserve most of their original in situ properties

spectral effects of time depth nonlinearities in deep sea sediment records a demodulation technique for realigning time and depth scales carbon 14 dating and percent caco3 in late pleistocene sediments suggest that deepsea sedimentation rates vary cyclically and that this cyclicity is related to climate sedimentation rate variability leads to nonlinearity in the time depth mapping function this nonlinearity can have profound affects on signal spectra leading to the development of harmonics and intermodulation tones these distortion effects in the spectra give a direct indication of the degree of nonlinearity thereby providing a tool for realigning time and depth scales a tuning technique is developed which assumes a direct link between climate as measured in 18o from planktonic foraminifer tests and sedimentation rates a criterion of spectral simplicity as quantified in the varimax norm is used to demodulate the input spectrum application of this technique to an equatorial pacific piston core erdc 84 found peak glacial sedimentation rates to be 30 higher than peak interglacial rates a figure in good agreement with 14c based estimates from the same area this technique is compatible with other time scale tuning techniques such as those using orbital parameters and in combination with these other techniques provides a method for fine tuning any late pleistocene record

leopards as taphonomic agents in dolomitic caves implications for bone accumulations in the hominid bearing deposits of south africa it has been hypothesised that leopards were significant contributors to the bone accumulations of the plio pleistocene hominid bearing caves of south africa interpretations of leopard activity in these fossil caves were previously based upon reports of modern leopard behaviour in areas of southern africa that were lacking in caves in 1991 a leopard lair with an accompanying bone accumulation was discovered in a dolomitic cave on the john nash nature reserve south africa all of the bones in this cave could be unambiguously attributed to the activity of one individual leopard over a 1 year period the resulting bone assemblage indicates that when available leopards will preferentially utilise the deep recesses of caves to the exclusion of trees when feeding and that the size of prey leopards are capable of capturing killing and transporting has previously been underestimated the implications this may have for understanding the accumulation of fossils in the hominid bearing caves of south africa are that bones derived form leopards consuming prey in trees probably did not contribute significantly to the assemblages and further that it is not necessary to invoke sabre tooth cat involvement for the larger animals found in these assemblages this modern cave probably represents a more appropriate model for the accumulation of bones in the fossil caves of the sterkfontein valley and the assemblage is being continually monitored to view any and all taphonomic alterations that are occurring

was flk north levels 1 2 a classic living floor of oldowan hominins or a taphonomically complex palimpsest dominated by large carnivore feeding behavior abstract from excavation at flk north levels 1 2 in 1960 1962 mary leakey reported approximately 1200 oldowan artifacts and 3300 large mammal fossils as a hominin living floor preliminary taphonomic analysis by bunn seemed supportive based on the presence of some cut marked bones the concentration of several dozen bovid individuals and the relative abundance of limbs and mandibles over other axial elements recent taphonomic analysis of leakey s entire fossil assemblage by dominguez rodrigo and barba however documents a minor hominin role at the site contrasted to the dominant role of carnivores felids brought prey animals hyenas scavenged from abandoned felid meals at different times hominins butchered several bovids and discarded artifacts at this dynamic location since 2006 renewed excavations at flk north and other sites by the olduvai paleoanthropology and paleoecology project toppp have expanded artifact and fossil samples and implemented new analytical approaches to clarify taphonomic histories of the olduvai paleolandscape at flk north 1000 new large mammal fossils from levels 1 to 2 show minimal butchery evidence amid abundant evidence of carnivore gnawing fracture rodent gnawing and sediment abrasion to help guide future excavation and analyses we have developed several alternative working hypotheses of site formation

sampling surface orientation and clast macrofabric in periglacial colluvium to isolate the influence of sampling surface orientation on the macrofabric of periglacial colluvial deposits clast orientation measurements were obtained from seven paired horizontal and vertical exposures in turf banked solifluction lobes on niwot ridge colorado front range most samples form moderately strong upslope plunging clusters aligned with the local slope orientation fabrics obtained from vertical faces were stronger than those from horizontal exposures in six of the pairs near horizontal sampling surfaces yield less biased results than vertical exposures owing to operator perceptions procedural difficulties and the relative thinness of the layer affected by colluvial processes sampling procedures must be standardized before comparative studies of colluvium can yield reliable results copyright 2001 john wiley sons ltd

solifluction induced modifications of archaeological levels simulation based on experimental data from a modern periglacial slope and application to french palaeolithic sites the taphonomic study of petit bost croix de canard and cantalouette ii three palaeolithic sites that were recently discovered near perigueux and bergerac dordogne france in a colluvial context has enlightened the difficulty of adequately appreciating the relative role of cultural and natural processes in site spatial patterning periglacial solifluction was thought to have played a significant role in site formation because the nature of the modifications induced by solifluction was still poorly understood a simulation was made using data of soil movement recorded at la mortice french southern alps 3100 m in elevation in a modern periglacial environment the results show that for a knapping location the first steps of deformation are typified both by a downslope translation of the location center and by an anisotropic diffusion of the artifacts the knapping spot becomes elongated along the slope with a dense relic concentration of artifacts in the upslope portion this type of pattern has been obtained after 100 to 200 years of simulated displacement according to the climatic and soil conditions that characterise the la mortice site the ultimate stages of deformation show that the artifact distribution tends to homogenise on larger surfaces and resemble a random distribution the ability of the simulated patterns to closely fit those observed in archaeological contexts is evaluated at three sites from south western france at petit bost the hypothesis of limited solifluction explains accurately the association of both cultural artifact concentrations and natural artifact preferred orientation features at croix de canard long term solifluction can be proposed by contrast the simulated patterns do not describe the structures observed on the steeper slopes at cantalouette ii where the knapping spot transforms into distinct solifluction lobes

effect of mechanical interactions on the development of shape preferred orientations a two dimensional experimental approach abstract modifications in the development of preferred orientations of rigid particles due to mechanical interactions between particles are studied experimentally in two dimensions experiments in both pure shear and simple shear were performed and the results analysed using an easy and fast new automatic method for increased concentration of rigid particles the rotation of individual particles may be slowed down or even stopped due to collisions or disturbance of the flow in the matrix caused by neighbours in coaxial flow the fabric intensity is consequently reduced in simple shear flow the fabric evolution is no longer cyclic the intensity is on average weaker and the fabric axis rotates asymptotically toward the shear plane in the case of preferred orientations of particles having a low aspect ratio 2 5 the fabric rotates through the shear plane then undergoes a reverse rotation and rotates toward the shear plane again in the light of these experimental results we emphasize that quantification of finite strain based on such fabrics may lead to significant underestimates and calculated values should be taken as minimum estimates the kinematic significance of concentrated rigid particle preferred orientations in rocks is modified by interactions between particles techniques for qualitative or quantitative kinematic analysis may become unreliable for simple shear flows the concentrated population fabrics show an angular behaviour close to that of passive markers they tend to align parallel to the shear plane in simple shear flow

signal analysis of cyclicity in maastrichtian pelagic chalks from the danish north sea abstract low field bulk magnetic susceptibility has been determined on maastrichtian chalk samples from a drill core from the dan field in the danish north sea fast fourier transformations fft have been used to detect possible cycles in the magnetic susceptibility data power spectra from the complete section and from sub sections of the magnetic susceptibility reveal two cyclicities of ca 0 4 cycles m and ca 1 7 cycles m which are present on a 90 confidence level signal analysis of natural gamma ray wire line log data supports these findings sedimentation rate estimates place the cycles in the milankovitch frequency band artificial time series are used to study the applicability of the fft to identifying cyclicity in chalks expected geological distortions e g hiati and sedimentation rate variations are introduced into the time series to investigate the response of the frequency spectra different methods of handling missing data intervals are also examined

the yukon tanana terrane part of north america at 215 ma from paleomagnetism of the taylor mountain batholith alaska abstract the massive unmetamorphosed 212 ma taylor mountain batholith underlies 648 km2 of the yukon tanana terrane ytt in east central alaska and intrudes klippen thrust sheets of the fortymile river assemblage and the chicken metamorphic complex structural evidence indicates that the batholith is neither tilted nor rotated about a vertical axis paleomagnetic analysis of 295 specimens from 24 sites in the batholith and cross cutting mafic dikes isolates a stable primary characteristic remanent magnetization in magnetite with unblocking temperatures of 500 to 585 c that places the batholith s paleopole at 61 4 n 102 2 e n 17 95 5 2 on the north american apparent polar wander path apwp at 215 5 ma 1 the taylor mountain paleopole alone and all ytt paleopoles together show that the ytt has been a para autochthonous part of the north american margin since the late triassic further the intermontane belt imb paleopoles are distinct from the north american and ytt paleopoles prior to the mid eocene and provide two apwp segments one imb segment includes the quesnel cache creek eastern coast belt and northern stikine terranes and the second more speculative imb segment includes the central and southwestern stikine and methow terranes this analysis supports tectonic models for the northern cordillera in which the imb terranes were obducted onto north america during the late cretaceous to mid eocene co eval with the laramide orogeny

the impact of periglacial processes on palaeolithic sites the case of sorted patterned grounds during the last glaciation western europe witnessed recurrent millennial scale episodes of periglacial climates that had significant impact on palaeolithic site preservation after a review on the genesis and climatic meaning of sorted patterned grounds examples of polygons stripes and stone banked solifluction lobes taken from archaeological contexts are described sorted features in palaeolithic sites imply that caution should be taken in site patterning analysis for reconstructing past human behaviours since spatial alteration of the original anthropogenic pattern took place on low gradients artefact movements remain limited but may increase dramatically on slopes when solifluction adds to sorting processes although these features are widespread in modern periglacial environments archaeological examples remain scarce multiple factors are probably involved including lack of knowledge of periglacial processes and landforms by archaeologists leading to misinterpretation but also more or less complete obliteration of surface features by sedimentary processes upon burial however it is assumed that scarcity of clear anthropogenic patterning in french palaeolithic sites before the late glacial is due for a large part to post depositional disturbance by periglacial processes

autochthony and orientation patterns in olduvai bed i a re examination of the status of post depositional biasing of archaeological assemblages from flk north flkn recent excavations at flk north olduvai gorge tanzania have produced new information on the orientation of archaeological materials at various levels of the site this information includes the uniform distribution of material azimuths which contrasts with previous inferences of highly patterned orientations of materials in the bed i archaeological sites those previous inferences of patterned material orientations are based on mary leakey s 50 year old drawings of artifact and fossil bone distribution but are not verified by our precise measurements of archaeological objects made in situ nor do those previous results agree with the general lack of geological geomorphological and or taphonomic data that would indicate significant post depositional movement of archaeological materials in the sites we argue here that leakey s drawings are incomplete only portions of each assemblage were drawn and inaccurate in their representation of the original locations shapes and orientations of most archaeological specimens this argument is supported by several important mismatches in object representations between a photograph taken of a small portion of the flk 22 zinjanthropus site floor before the removal of the archaeological items and the sketch of the same area drawn by leakey thus we conclude that primary orientation data of excavations i e direct measurements taken from items generated prior to object removal are the only valid indicators of the relative isotropy or anisotropy of these important paleoanthropological assemblages

the site formation history of schoningen 13ii 4 germany testing different models of site formation by means of spatial analysis spatial statistics and orientation analysis abstract the lower palaeolithic middle pleistocene locality schoningen has been a focus of archaeological research for over two decades the locality is best known for the discovery of wooden spears in close association with numerous butchered remains of horses and other large mammals in the spear horizon scho 13ii 4 with an age of ca 300 kyr several site formation models have been proposed to explain the faunal accumulation at the site 1 single hunting event on a dried lake shore 2 multiple hunting events in the soft mud of a lake shore 3 deposition on an exposed delta plain 4 geogenic displacement by hydrological processes 5 hominin waste disposal and storage behaviour and 6 hominin butchering activities on a frozen lake surface visual spatial analyses allow for the subjective incorporation of archaeological knowledge in the interpretation of spatial data while spatial statistics allow for more objective and reproducible inferences about spatial patterns the combination of the two could thus provide a vital tool in disentangling complex site formation processes this study uses a combination of visual spatial analyses spatial statistics and orientation analyses in order to further disentangle the site formation history of scho 13ii 4 and to assess the impact of post depositional processes on the faunal assemblage this study revealed the existence of intra site and inter species differences in spatial distribution and orientation the results of this study are compared to the suggested site formation models for scho 13ii 4 to test which of these models is most parsimonious with the spatial distribution and orientation of the faunal assemblage it is concluded that the previously proposed site formation models are overly simplified and cannot be used to explain the site formation history of scho 13ii 4

evidence for a change in the periodicity of tropical climate cycles at 2 4 myr from whole core magnetic susceptibility measurements the earth s orbit about the sun is influenced by gravitational interactions with the moon and other planets the resulting orbital perturbations give rise to cyclical variations in orbital eccentricity obliquity and precession with periods of 100 41 19 and 23 kyr respectively1 these variations are climatically important because they affect the seasonal and latitudinal distribution of solar radiation magnetic susceptibility measurements in deep sea sediment cores can be used as a sensitive indicator of temporal variations in the concentration of terrigenous material supplied to the sea bed here we use this approach to study the evolution of cycles of terrigenous sedimentation at ocean drilling program sites in the arabian sea and the eastern tropical atlantic we show from spectral analyses of the two susceptibility time series spanning the past 3 2 3 5 myr that the records are driven strongly by orbital forcing before 2 4 myr before present bp both records are strongly influenced by the 23 and 19 kyr periodicities but after 2 4 myr they are both significantly influenced by the 41 kyr periodicity this shift coincides with the beginning of major northern hemisphere glaciation which indicates for the indian ocean site that the supply of terrigenous sediment carried by monsoonal winds has responded to the rapid increase in ice cover at this time we cannot however exclude possible effects of changes in bottom water circulation on the susceptibility record of the atlantic site

disentangling hominin and carnivore activities near a spring at flk north olduvai gorge tanzania flk north is one of the densest concentrations of fossils found in olduvai gorge a recent taphonomic re evaluation of the collection excavated by leakey at the site suggests that it was a palimpsest in which most of the animals were accumulated and modified by carnivores the lithic tools therefore seem to have an independent depositional history from most of the fauna the present study based on new excavations expands the evidence supporting this interpretation and demonstrates a thicker deposit than was reported by leakey including new archaeological levels it also shows that in the few instances where hominins butchered carcasses meat not marrow was their main target this argues against passive scavenging hypotheses which emphasize the dietary role of marrow and instead underscores the importance of meat in the diet of early pleistocene hominins

simultaneous presence of orbital inclination and eccentricity in proxy climate records from ocean drilling program site 806 ocean drilling program site 806 in the western pacific shows evidence of a remarkably constant average sedimentation rate this feature allows us to analyze ancient climate proxies without the need for orbital tuning a standard procedure in prior work but one that can lead to biased results spectral analysis of stable oxygen isotope ratios at this site a proxy for global ice volume shows a single narrow peak with a period 100 k y a result that supports our model which links glacial cycles to variations in the inclination of the earth s orbit in contrast spectral analysis of the coarse component fraction of the sediment primarily foraminifera shows a structure characteristic of standard milankovitch theory with a triplet of peaks with periods near those expected from the earth s eccentricity 95 125 and 400 k y bispectral analysis confirms these linkages but suggests that orbital inclination also plays some role in the coarse fraction from the clear presence of both signals in different proxies at the same site we conclude that although eccentricity affected the local climate it is orbital inclination that drove the variations in the global ice volume for the past million years

taphonomy of a middle miocene autochthonous forest assemblage ngorora formation central kenya abstract a 12 6 million year old forest assemblage of leaves twigs and rare fruit is preserved in the ngorora formation of central kenya the assemblage is autochtonous preserved in airfall tuff and represents well the diversity heterogeneity and richness of the original forest the herbaceous component not usually preserved in paleobotanical assemblages is present nearest neighbor analysis and mapping of the vertical distribution of plant organs indicates that leaves and twigs are preserved near the parent plant and that there is no apparent size weight or species bias in deposition of these remains leaves occur isolated in clusters or attached to branches and fell directly to the ground as a result of ashfall most falling very soon after ashfall commenced the absence of upright trunks and large stems is probably due to post depositional weathering which may also be responsible for the absence of a leaf litter layer however leaf litter may have been absent at the time of ash deposition

the late cenozoic uplift climate change paradox the geologic evidence for worldwide uplift of mountain ranges in the neogene is ambiguous estimates of paleoelevation vary according to whether they are based on the characteristics of fossil floras on the masses and grain sizes of eroded sediments or on calculations of increased thickness of the lithosphere as a result of faulting detrital erosion rates can be increased both by increased relief in the drainage basin and by a change to more seasonal rainfall patterns the geologic record provides no clear answer to the question whether uplift caused the climatic deterioration of the neogene or whether the changing climate affected the erosion system in such a way as to create an illusion of uplift we suggest that the spread of c4 plants in the late miocene may have altered both the erosion and climate systems these changes are responsible for the apparent contradictions between data supporting uplift and those supporting high elevations in the past

sediment focusing creates 100 ka cycles in interplanetary dust accumulation on the ontong java plateau the accumulation of extraterrestrial 3 he a tracer for interplanetary dust particles idps in sediments from the ontong java plateau ojp western equatorial pacific ocean has been shown previously to exhibit a regular cyclicity during the late pleistocene with a period of v100 ka those results have been interpreted to reflect periodic variability in the global accretion of idps that in turn has been linked to changes in the inclination of earth s orbit with respect to the invariable plane of the solar system here we show that the accumulation in ojp sediments of authigenic 230 th produced by radioactive decay of 234 u in seawater exhibits a 100 ka cyclicity similar in phase and amplitude to that evident in the 3 he record we interpret the similar patterns of 230 th and 3 he accumulation to reflect a common origin within the ocean climate system comparing spatial and temporal patterns of sediment accumulation against regional patterns of biological productivity and against the well established pattern of caco3 dissolution in the deep pacific ocean leads to the further conclusion that a common 100 ka cycle in accumulation of biogenic authigenic and extraterrestrial constituents in ojp sediments reflects the influence of climate related changes in sediment focusing rather than changes in the rate of production or supply of sedimentary constituents 7 2002 elsevier science b v all rights reserved

a spatial analysis of stone tools and fossil bones at flk zinj 22 and ptk i bed i olduvai gorge tanzania and its bearing on the social organization of early humans abstract over the past twenty years early hominin behavioral models have increasingly abandoned social inferences of the behaviors that created the earliest archaeological record behavioral reconstructions have focused mostly on the subsistence strategies that conditioned the selection of specific loci i e central places and the manipulation and consumption of resources therein i e raw material transport and use and carcass acquisition and processing part of the reason why the social component of these behaviors has been marginalized lies in the lack of proper modern analogs and also in a lack of analytical tools to link social organization to subsistence spatial analysis of the debris patterns generated by modern foragers depending on their social organizations is a potentially useful tool to understand behavior in the past the application of statistical spatial analyses to the distribution of stone tools and bones provides an insightful approach to understand socio economic behavior at any given site provided a significant part of the archaeological record of a large paleo surface has been exposed through excavation this is the case of flk zinj and ptk i a statistical spatial analysis of these sites shows a spatial interdependence between tools and bones it also shows that the single dense cluster pattern at these sites is not a preservation issue or a sampling artifact but the result of a socio economic organization by early humans that differed from those currently documented among h sapiens foragers

rates and processes of periglacial solifluction an experimental approach cold room physical modelling of periglacial solifluction processes on an experimental slope of 12 is described and data on soil temperatures surface frost heave thaw consolidation downslope soil movement and porewater pressures over seven freeze thaw cycles are presented these data are analyzed in the context of laboratory determination of the rheometry of the experimental soils at high moisture contents it is concluded that the observed thaw induced solifluction represents pre failure soil shear strain and results from loss of strength due to the combined effects of raised porewater pressures during thaw consolidation and upward seepage pressures as water flows towards the surface away from the thaw front an investigation of the rheometry of thawing soils offers the prospect of an analytical model to predict rates and depths of periglacial solifluction 1997 by john wiley sons ltd

correlation of the magnetic susceptibility stratigraphy of chinese loess and the marine oxygen isotope record chronological and palaeoclimatic implications abstract the thick deposits of wind blown silt of the loess plateau in central china constitute arguably the most important terrestrial record of the late pliocene and pleistocene climate magnetic susceptibility stratigraphy has proven extremely useful for quantifying the palaeoclimatic record of chinese loess with intervals of high magnetic susceptibility corresponding to warm humid interglacials and intervals of low susceptibility to cooler drier glacials several workers have noted that the magnetic susceptibility stratigraphy strongly resembles the marine oxygen isotope record for which a high resolution chronology is available from tuning to the frequencies of earth orbital parameters attempts have been made to correlate the two records statistically and we use this approach to generate a new magnetic susceptibility time series for the central chinese loess plateau our results suggest that the two records are sufficiently similar over the interval ca 0 1 5 my bp for this approach to yield a useful age model for loess accumulation spectral analysis of the resulting magnetic susceptibility time series clearly shows that the growth of 100 ky variance which occurs in the marine oxygen isotope record after about 1 my bp also occurs synchronously in the magnetic susceptibility record reinforcing recent suggestions of a strong linkage between the high latitude northern hemisphere and the asian climate we also show that a significant improvement in the strength of the loess magnetic susceptibility marine oxygen isotope correlation occurs after about 1 5 my bp which corresponds to a significant increase in the rate of sediment accumulation across the loess plateau

sedimentary cyclicity in the marine pliocene pleistocene of the wanganui basin new zealand sequence stratigraphic motifs characteristic of the past 2 5 m y earth s climatic history since 2 5 ma has been controlled by milankovitch variations in the planetary orbit comprising alternate periods of glaciation and interglaciation with a dominant frequency of 41 000 yr concomitantly eustatic sea level has fluctuated 70 to 130 m causing rapid transgressions and regressions of the shoreline across the world s continental shelves the resulting sedimentary record is cyclothemic each cyclothem corresponding to a single climate and sea level cycle the wanganui basin new zealand contains a 2 km thick almost complete composite record since isotope stage 100 ca 2 5 ma in the form of 47 superposed cyclothems of shelf origin each cyclothem corresponds to an unconformity bound stratigraphic sequence and typically contains a transgressive systems tract sometimes a mid cycle shell bed a highstand systems tract and sometimes a regressive systems tract no advantage accrues from using transgressive regressive units rather than cyclothems and or sequences in description of the succession six basic sequence motifs represent deposition in locations between the shoreline and offshore shelf i e the hawera birdgrove turakina seafield castlecliff and rangitikei motifs a seventh the nukumaru motif which includes dominant coquina limestone represents deposition in shallow water areas of reduced terrigenous sediment on the flank of the basin the sequence motifs represented in any section change systematically in sympathy with basin scale changes in subsidence and sediment supply in contrast with the 41000 year length of individual glacioeustatic sequences these basin wide tectonic cycles have a periodicity of many hundreds of thousands to a few million years i e that of third or fourth order sequences of the exxon type this coupled with the restriction of strongly cyclothemic sediments to geological periods of known glacio eustasy permiancarboniferous pliocene pleistocene suggests that tectonic subsidence cycles rather than glacio eustasy are the driving forces behind the development of the third and fourth order unconformity bound sequences that are reported to occur throughout the stratigraphic record

paleomagnetism of the upper cretaceous strata of mount tatlow evidence for 3000 km of northward displacement of the eastern coast belt british columbia this study contributes the first paleomagnetic data from dated cretaceous units of the coast belt 51 3 n 123 8 w in which paleohorizontal bedding surfaces can be identified with certainty we sampled 38 sites through a 1 5 km stratigraphic interval of cenomanian silverquick sedimentary strata and cenomanian to campanian powell creek volcanics in the tatlow syncline in the tyaughton methow basin magnetizations at 21 sites have high unblocking temperatures tub and pass the tilt test precision k 5 before untilting maximum k 48 after 100 untilting magnetic minerals of volcanics show original textures mean declinations in volcanic and sedimentary rocks are statistically identical and polarity is consistently normal the mean inclination 55 4 3 4 probability p 0 05 of this pretilting magnetization is 20 1 4 0 shallower than that expected if the rocks were deposited in their present position relative to cratonic north america field and laboratory observations rule out other causes for these anomalous shallow inclinations these rocks therefore have been displaced northward by 3000 500 km relative to cratonic north america since mid cretaceous time this displacement is almost 3 times greater than that estimated from mid cretaceous volcanics in the now adjacent intermontane belt evidently the two belts were not amalgamated until latest cretaceous or early tertiary time these results are inconsistent with all previous geologically based tectonic reconstructions of the cordillera magnetizations at eight sites in silverquick and powell creek beds have low tub and directional characteristics similar to those in three younger diorite intrusions reversed and normal polarities occur the rocks are commonly highly altered and maximum precision occurs after 40 untilting the magnetizations therefore are interpreted as overprints of latest cretaceous age acquired during folding

development of miniature sorted patterned ground following soil erosion in east falkland south atlantic miniature sorted patterned ground features nets and stripes occur at an elevation of ca 35 m in the l antioja valley east falkland the features have developed following recent soil erosion and display many of the characteristics associated with the operation of frost related processes in regolith materials the patterns are currently active and indicate that in cool oceanic climates the distribution of frost sorted patterns is controlled by the presence of bare ground on suitable regolith rather than by altitude

provenance analysis of oligocene autochthonous and allochthonous coralline algae a quantitative approach towards reconstructing transported assemblages abstract the oligocene shallow water carbonates of the lower inn valley tyrol northern calcareous alps contain a rich coralline algal flora these carbonates are known from two distinct settings 1 autochthonous limestones and 2 debris flows intercalated with deeper water marls the carbonate facies are dominated not only by crustose coralline algae corallinaceae rhodophyta but also by smaller and larger benthic foraminifers bryozoans corals as well as lithoclasts of triassic origin five species of coralline algae are identified and described in detail lithoporella melobesioides lithothamnion sp a lithothamnion sp b mesophyllum sp and sporolithon sp the distribution of algal taxa shows distinct relationships to non algal biota and substrates l melobesioides preferably encrusts other coralline algae lithothamnion sp a is found encrusting bryozoans lithothamnion sp b encrusts corals while mesophyllum sp grows directly on fine grained soft substrates besides the fact that algal taxa reveal close relationships to other components it can also be shown that algal assemblages are highly correlated to carbonate facies types hierarchical cluster analysis based on the relative abundance of taxa reveals five coralline algal assemblages showing distinct distribution patterns among carbonate facies while two of the assemblages are restricted to the debris flows the other three were found in both debris flows and autochthonous occurrences a correlation between algal assemblages and carbonate facies allows the following conclusions to be made 1 both coralline algal taxa in particular and algal assemblages as a whole show distinct relations to water depth herein referred to as a summary of light conditions and hydrodynamic energy and substrate relationships this makes them potentially valuable indicators for palaeoecological reconstructions 2 most of the coralline algal assemblages in allochthonous occurrences i e debris flow can be traced back to facies patterns in autochthonous occurrences this indicates that a thorough microfacies analysis combined with a systematic study of specific components can be very useful in the reconstruction of palaeoenvironments even if these are not preserved in their original context 3 some of the coralline algal assemblages within debris flows cannot be traced to autochthonous facies and do not seem to reflect primary facies compositions as they contain an atypical mixture of algal taxa and other components these are characterised by a relatively high abundance of lithoclasts usually 20 of the components and a high degree of fragmentation of coralline algae thalli

paleoenvironmental and paleoecological reconstruction of a freshwater oasis in savannah grassland at flk north olduvai gorge tanzania the records of early hominins are commonly localized both temporally and spatially even in archaeologically rich basins like olduvai gorge tanzania the flk north site was discovered in 1960 but the reason for the exact location of this dense concentration of fossils and stone tools on a lake margin flat has not been explained we present new geological and geochemical information from six excavations in upper bed i which revealed up to 1 4 m thick carbonate deposits attesting to the presence of freshwater springs in the area surrounding flk north the 18o signatures of the tufa are typical for meteoric water that has evolved during evaporation tuff if that caps the sequence was deposited on uneven topography with the highest area a low relief ridge between two faults at the archaeological site and lowest areas being sites of groundwater discharge the model proposed here is that rainfall on adjacent highlands was transported to the basin where faults acted as conduits for water similar hydrogeological settings at modern lakes manyara and eyasi currently support lush groundwater forest and woodland despite arid climate flk north may have been an oasis offering freshwater and shelter for consuming meat by both carnivores and hominins

victoria cabrera site a middle stone age site at olduvai gorge tanzania olduvai gorge tanzania is a key site for the study and comprehension of human evolution in east africa however the origin of homo sapiens and the middle stone age have been poorly understood in the gorge thus far in this study we present the dating taphonomic technological and typological analyses of the lithic industry and faunal remains excavated at the victoria cabrera site vcs during the 2017 fieldwork season the stratigraphic sequence of the site contains several levels of fluvial origin some of them with lithic and faunal remains most remains lithics and bones are affected by rounding processes infrared stimulated luminescence irsl dating has provided ages between 90 and 70 ka bp for these layers that can be related to the marine isotope stage 5a lithics are scarce and the dominant raw materials are naibor soit quarzite and basalt followed by phonolite chert and quartz as the most common raw materials the lithic technology is based on the production of flakes obtained from prepared cores with the discoid method and to a lesser extent the levallois method being the most frequently used the retouched blanks are described as substratum or domestic tools sidescrapers notches or denticulates there is just one heavy duty piece and points are absent the faunal assemblage includes alcelaphinae antilopinae and equidae the major parts of the unidentified faunal remains are size 3 ungulates followed by carcasses of size 2 and size 4 species we cannot relate lithic and bones because no cut marks or percussion marks have been identified and carnivore action is scarce in sum vcs represents the first accurately dated middle stone age site with lithic and faunal remains in olduvai gorge

fabric of palaeolithic levels methods and implications for site formation processes fabric analysis in archaeological contexts i e the study of the orientation and dip of artefacts has been significantly improved during the last decade mainly with respect to the statistical treatment of data the development of a reference base for natural sedimentary processes as well as the increased number of data for palaeolithic levels these works show that fabrics are an efficient tool for assessing site formation processes fabrics allow discrimination between i undisturbed or minimally disturbed levels ii levels that have undergone strong pedoturbations due to biological activity or to shrinking and swelling of clayey sediments and iii levels that have been significantly reworked by slope processes such as periglacial solifluction or overland flow however in the present state of knowledge fabrics do not allow precise estimation of the degree of perturbation if not associated with other archaeological and geological criteria from the set of data on french palaeolithic sites used here it is demonstrated that slope dynamics and particularly solifluction for sites predating the late glacial may have played an important role in site formation

magnetic susceptibility variations in upper pleistocene deep sea sediments of the ne atlantic implications for ice rafting and paleocirculation at the last glacial maximum magnetic susceptibility ms variations are used to intercorrelate 17 upper pleistocene sediment cores taken from the ne atlantic between 40 degrees and 60 degrees n the ms based correlation depends on regionally consistent patterns of variation in the deposition of ice rafted detritus ird in response to pleistocene glaciations and especially to high frequency ice rafting episodes referred to in recent studies as heinrich events the sedimentological and rock magnetic basis for the apparent relationship between the ms signal and ird content of ne atlantic sediments is examined by 1 comparing the ms profiles of selected cores with their records of coarse fraction 150 mu m lithic fragment abundance and neogloboquadrina pachyderma sin percentages and 2 normalizing ms by expressing it both on a carbonate free basis and as a quotient with anhysteretic remanent magnetization a parameter sensitive to magnetic mineral grain size variations these comparisons show that variations in bulk sediment ms are only partly driven by simple carbonate dilution productivity and dissolution effects changes in both the concentration and grain size of magnetic minerals within the lithogenic noncarbonate fraction also impose a significant influence on bulk ms values in particular horizons rich in ird are associated with significant increases in the relative proportion of coarse grained multidomain ferrimagnetic particles in the sediment this is because ice rafting in contrast to most other mechanisms capable of transporting detrital magnetic minerals to pelagic environments has a high potential for delivering large ferrimagnetic grains as components of sand sized polycrystalline lithic fragments this fundamental linkage between the ird content and ms signal of ne atlantic sediments is used to reconstruct the patterns of variation in ird deposition and by inference surface currents of the last glacial maximum lgm similar to 18 19 ka relative to the present day ne atlantic using the time slice mapping approach developed by the climap project group our lgm holocene ms ratio map based on sample pairs from over 80 deep sea cores confirms that there was a weak cyclonic gyre north of the polar front in the lgm north atlantic the gyre comprised a sluggish warm current in the ne atlantic flowing north between latitudes 47 degrees and 62 degrees n partly fed by subtropical waters from south of the polar front and carrying large numbers of icebergs derived from several sources most of which melted between latitudes 45 degrees and 52 degrees n the warm current probably continued its flow into the iceland basin where it fed into a south flowing current which transported melting icebergs from iceland and scandinavia along the western flank of the reykjanes ridge

gombore ii melka kunture ethiopia a new approach to formation processes and spatial patterns of an early pleistocene acheulean site abstract to assess the integrity of pleistocene archaeological sites is crucial in the analysis of human behaviour most of the early palaeolithic sites are in active fluvial environments where it is necessary to understand the degree of sedimentary disturbance the analysis of the formation processes through geoarchaeological and geostatistical techniques offers new tools to evaluate if the archaeological assemblage is in autochthonous or allochthonous position gombore ii 850 ka within the archaeological and paleontological complex of melka kunture ethiopia extends over estimated 1000 m2 and yielded a large number of acheulean artefacts fossil mammal bones and two fossil hominin remains the geomorphological setting and deposition patterns of high energy sedimentation in a fluvial channelized environment are similar to those of many other early palaeolithic african sites this is traditionally described as producing a disturbed record with the fortuitous association of faunal remains and lithic industry driven by fluvial processes to assess this hypothesis we analyse here the formation processes and the spatial patterning of the remains we apply geoarchaeological orientation and fabric and spatial tests density grouping k means to the mapped archaeological surfaces and to a present day fluvial surface we observe substantial differences in geoarchaeological features and spatial patterning between the archaeological record lithic materials and faunal remains and the natural clasts of both the archaeological deposit and the bed of the present day river this suggests different depositional processes or temporal events we conclude that the remains produced by the hominins did not haphazardly accumulate after extensive erosion and re sedimentation they rather preserve a reasonable degree of taphonomic and spatial integrity and are possibly representative of different activities

one bone two bones wet bones dry bones transport potentials under experimental conditions flume experiments demonstrated that bones had varying hydraulic transport potentials depending on whether the bones were wet or dry articulated or disarticulated when placed into a water flow dry and articulated bones demonstrated the greatest transport potential while wet and disarticulated bones demonstrated the least the velocity at which bones were transported was plotted against a range of attributes such as the shape weight volume and density of the bones with varying degrees of success although several attributes did prove to be significant as indicators of bone transport potential no single attribute emerged as more useful than another

new archaeological and geological research at shk main site bed ii olduvai gorge tanzania abstract this work presents the new round of archaeological research undertaken in shk main site since 2009 through new geological correlations and dating within the bed ii sequence and a new stratigraphic description of the site new chronological and contextual information is provided for this site archaeo stratigraphic analysis of the vertical distribution of the archaeological aggregate a gis based restitution of the horizontal associations and a taphonomic interpretation of the formation processes allow a first intra site analysis of this high density anthropogenic patch within the paleo landscape of the olduvai basin

periodicity of mesoscale phanerozoic sedimentary cycles and the role of milankovitch orbital modulation data on more than 200 mesoscale sedimentary cycles indicate that phanerozoic cycle periods are randomly distributed with respect to the four major milankovitch orbital parameters except late mississippian through late pennsylvanian cycles which show positive clustering about the 413 000 yr eccentricity period cycle periods calculated from average thicknesses and accumulation rates are strongly dependent on the former correlation coefficient 0 802 but relatively independent of the latter correlation coefficient 0 360 hence calculated period is largely a function of average cycle thickness and milankovitch range periods will be preferentially calculated for cycles with average thicknesses between 1 m and 20 m regardless of actual causes of cyclicity for individual cyclic sequences arguments for milankovitch control based solely on average period are unfounded comparison of short term holocene sedimentation rates and long term phanerozoic accumulation rates for cyclic peritidal and delta

orbital frequencies in radiolarian assemblages of the central indian ocean implications on the indian summer monsoon radiolarian distribution in surface sediments and its relationships with overlying surface oceanography provided impetus for down core faunal variation related to changes in monsoon intensity due to the earth s orbital eccentricity in the geologic past in present study a high resolution t 4 75 ka radiolarian distribution for the last 485 ka in a core aas 2 3 from the central indian ocean basin revealed orbital and sub orbital cycles relationships between temporal distribution of 1 high salinity pyloniids and didymocyrtis 2 low salinity spongodiscids and spongaster 3 transitional euchitoniids and 4 southern anthocyrtidium assemblages and the orbital forcing etp i e the normalized sum of the earth s eccentricity tilt and precession and the may july insolation were analyzed spectral analyses revealed significant cycles of pyloniids 400 126 95 54 41 31 23 19 17 and 15 ka spongaster 95 41 29 23 19 17 and 15 ka euchitoniids 126 95 51 31 21 18 and 17 ka and anthocyrtidium 400 69 41 31 23 19 and 15 ka cross spectral analysis between pyloniids and etp suggested coherent pyloniid cycles lagging etp by 9 ka at 100 ka eccentricity while both were in phase 2 ka at 41 ka tilt and 23 ka precession cycles coherent spongaster cycles led etp by 38 ka at 100 ka eccentricity 15 ka at 41 ka tilt 5 ka at 23 ka precession cycles coherent anthocyrtidium cycles led etp by 14 ka at 100 ka eccentricity 10 ka at 31 ka tilt and were in phase at 41 ka tilt as well as 23 and 19 ka precession cycles similarly a radiolarian monsoon index defined as the normalized sum of pyloniids didymocyrtis spongodiscids spongaster euchitoniids and anthocyrtidium pdssea led etp at 54 and 23 ka cycles while both were nearly in phase at 41 31 and 15 ka cycles coherent pdssea cycles led insolation during may july at 8 s core site at 23 ka precession lagged 100 54 and 29 ka cycles and were in phase at 41 ka tilt and 15 ka sub orbital cycles the results suggest that radiolarian assemblages exhibit proxy monsoon cycles due to the earth s orbital eccentricity at 400 126 and 95 ka tilt at 54 41 and 31 ka next to precession at 23 19 and 17 ka as well as insolation forcings at the core site during the late quaternary

is the spectral signature of the 100 kyr glacial cycle consistent with a milankovitch origin spectral analysis techniques traditionally applied to proxy climate records have involved the use of specialized windowing functions because of the finite length of the record available these have the effect of artificially broadening the spectral peaks such that closely spaced peaks may not be fully resolved alternatively use of a simple boxcar window following muller and macdonald 1997b will maximize the spectral frequency resolution this is achieved at the expense of potential truncation artifacts manifested as spurious peaks in the spectra although in the spectral analyses presented here such additional peaks are not significant in addition simple methods like this are not able to place any confidence intervals on the results global ice volume proxy records obtained

pebble orientation on large experimental debris flow deposits abstract replicable pronounced orientation of discoid pebbles 8 mm embedded on surfaces of large 10 m3 experimental debris flow deposits reveals that strongly aligned imbricate fabric can develop rapidly over short distances in mass flows pebble long axes aligned subparallel to deposit margins as well as subparallel to margins of surge waves arrested within the deposits pebble alignment exhibited modes both parallel to a p the primary flow direction intermediate axes dipped preferentially inward from surge wave margins b i orientation repetitive development of margin parallel imbricate fabric distributed across deposit surfaces provides compelling evidence that deposits formed dominantly through progressive incremental accretion rather than through simple en masse emplacement pronounced fabric along deposit and arrested surge wave margins reflects significant grain interaction along flow margins this sedimentological evidence for significant marginal grain interaction complements theoretical analyses iverson 1997 and other experimental data major 1996 iverson 1997 that indicate that resistance along flow margins is an important factor affecting debris flow deposition the fabric on the experimental deposits demonstrates that debris flows can develop strongly imbricate particle orientation that mimics fabric developed during fluvial deposition particle shape and local stress fields appear to have more control over fabric development than does general depositional process other criteria in addition to particle orientation are needed to discriminate mass flow from fluvial gravel deposits and to unravel depositional history

differential frost heave and sorted patterned ground field measurements and a laboratory experiment abstract small scale sorted stripes and circles dominate over the alpine regions in the upper engadin swiss alps most of these features are spaced at less than 30 cm intervals by coarse margins shallower than 5 cm monitoring of sorted stripes indicates that shallow diurnal freezing often induces differences in amount and timing of frost heave by needle ice growth between fine and coarse stripes while deeper diurnal freezing and seasonal freezing rarely differentiate heave amounts of the two materials a laboratory simulation is designed to explore the contribution of differential frost heave to the sorting process at the monitoring site the device consists of a fine part loam and a coarse part a granule layer mounted on loam freeze thaw tests with a granule mantle of 0 5 2 5 and 5 cm thick demonstrate that the heave amount on the coarse part is greatly reduced by the 5 cm thick mantle and that the coarse part always heaves later but subsides earlier than the fine as a result of this time lag in frost heaving lateral soil movement towards the coarse part is generated within the surficial soil differential heave associated with diurnal freeze thaw cycles is capable of sorting of the top 5 cm of soil

does clast size influence fabric strength abstract clast fabric strength is commonly used as a quantitative tool to determine the depositional history of subglacial tills this paper emphasizes the variance in fabric strength relative to clast size data on 46 clast fabric analyses were sampled from two basal till localities in southeast denmark and another eleven analyses from a basal till locality beyond a glacier in south iceland it is demonstrated that clasts longer than 2 3 cm show a stronger preference for parallel orientation than do shorter clasts this implies that two operators sampling fabric data a few meters apart within the same till unit but selecting clasts longer or shorter than 20 mm may classify the till as two different types of basal till because of differences in clast size alone additionally this study demonstrates considerable variations in fabric strength over short lateral distances within the same basal till bed it is concluded that caution should be exercised in using eigenvalues to infer depositional processes and strain histories in subglacial environments sedimentological criteria other than clast fabric must also be considered before drawing final conclusions on subglacial deposition

cretaceous coast belt paleomagnetic data from the spetch creek pluton british columbia evidence for the tilt and moderate displacement model well grouped stable magnetizations have been isolated at 14 of 20 sites sampled from the spetch creek pluton the single polarity primary magnetization directed at d 026 2 i 73 5 95 4 4 paleolatitude 59 7 n paleopole 73 n 078 w a95 7 was acquired around 88 ma during the cretaceous normal polarity superchron 118 84 ma this direction is discordant from the expected mid cretaceous direction d 332 5 i 75 1 for north america the difference could be caused by one of two end member models the all tilt model requires a 15 east side up tilt about a horizontal axis striking 353 and the displacement rotation model requires 330 770 km of northward displacement combined with 54 14 of clockwise rotation regardless this result provides a negative test of the baja british columbia model which requires 2400 km of northward displacement a review of previously observed mid cretaceous magnetizations from the coast belt which are also discordant indicates that they exhibit co

the variation of the southwest monsoon from the high resolution pollen record in heqing basin yunnan province china for the last 2 78 ma abstract a high resolution pollen record has been obtained from the heqing basin of yunnan province china the 737 72 m long continuous lacustrine sequence covers the last 2 78 ma according to the results of ams 14 c and magnetostratigraphy dating seven pollen ecological groups several high percentage pollen taxa and two palynological diversity indices d total and h total are combined to reconstruct synthetically the palaeoclimatic evolution in the heqing region of yunnan province according to the palaeoclimatic changes eight major variations of the southwest monsoon occurred during the periods 2 780 2 729 ma 2 608 1 447 ma and 0 342 0 118 ma the climate was predominantly relative warm and dry indicating a rather weak southwest monsoon between 2 729 and 2 608 ma the climate was mostly humid with increased rainfall seasonality mirroring a relative strong southwest monsoon from 1 447 to 0 342 ma the southwest monsoon gradually strengthened and its intensity achieved its maximum strength within wet phases between 0 991 and 0 342 ma the southwest monsoon during the period 0 118 ma 11 83 ka bp fluctuated greatly with a pattern of weak strong weak the spectral analysis of mesic conifer pollen percentages revealed that the climate and the southwest monsoon in the heqing region have been dominated by the 100 ka eccentricity period and also influenced by the other major orbital and sub orbital frequencies including 400 ka eccentricity obliquity 41 and 29 ka periods 23 ka precession and 10 ka

glacial cycles and astronomical forcing narrow spectral features in ocean sediment records offer strong evidence that the cycles of glaciation were driven by astronomical forces two million years ago the cycles match the 41 000 year period of earth s obliquity this supports the croll milankovitch theory which attributes the cycles to variations in insolation but for the past million years the spectrum is dominated by a single 100 000 year feature and is a poor match to the predictions of insolation models the spectrum can be accounted for by a theory that derives the cycles of glaciation from variations in the inclination of earth s orbital plane

self organization of sorted patterned ground striking circular labyrinthine polygonal and striped patterns of stones and soil self organize in many polar and high alpine environments these forms emerge because freeze thaw cycles drive an interplay between two feedback mechanisms first formation of ice lenses in freezing soil sorts stones and soil by displacing soil toward soil rich domains and stones toward stone rich domains second stones are transported along the axis of elongate stone domains which are squeezed and confined as freezing soil domains expand in a numerical model implementing these feedbacks circles labyrinths and islands form when sorting dominates polygonal networks form when stone domain squeezing and confinement dominate and stripes form as hillslope gradient is increased

the paleoecology and taphonomy of amk bed i olduvai gorge and its contributions to the understanding of the zinj paleolandscape abstract amk amin mturi korongo is a newly discovered site situated under tuff ic bed i 1 84 ma it contains several fossiliferous levels and the top one is situated on the same paleosurface as flk zinj for the first time this allows sampling the zinj paleoenvironment well into the secondary gorge and expands the known area of this paleolandscape fossils found at this site show exceptional preservation several articulated units have been discovered indicating minimal postdepositional disturbance and rapid sedimentation this assemblage allows a general estimation of time span the most elusive variable in archaeological analyses for the formation of amk phytolith analyses have discovered a dense palm forest at the site expanding the forested area known on the slightly elevated platform that contains the flk zinj flk nn ptk sites although a few artifacts have been discovered in the vicinity of amk the site was mostly naturally i e non anthropogenically formed this is of major relevance to determine that factors other than forested habitats must have influenced the formation of anthropogenic sites on the same platform as amk in the olduvai lacustrine basin

application of gis methods to retrieve orientation patterns from imagery a case study from beds i and ii olduvai gorge tanzania abstract the role of natural processes in the formation of the bed i and ii sites at olduvai gorge tanzania remains the subject of much debate five decades after their original excavation preferred orientation of items is indicative of water disturbance but compass bearings were not available in mary leakey s 1971 study using gis methods we have vectorized maps from 1960s excavations at olduvai and applied a range of statistical techniques to calculate items strike the gis analysis suggests strongly preferred orientation patterns in bed i and more heterogeneous angular histograms in bed ii two complementary lines of evidence support these results firstly modelling of potential mapping errors provides a large interval of confidence for preferred orientation patterns second the gis study was extended to photographs of the earlier excavations and to maps from recent fieldwork at olduvai both yielded patterned arrangement of lithics and bones and are consistent with results based on the analysis of the 1960s maps i e a large number of the bed i and ii assemblages are preferentially oriented these results highlight the potential of gis applications to the analysis of imagery in stone age studies and bear important implications for the understanding of the role of natural agents in site formation processes at olduvai

eocene rotation of the coast plutonic complex and intermontane belt paleomagnetism of eocene plutons along the klondike highway paleomagnetic results are reported for the 59 ma skagway 54 ma fraser 53 ma summit lake and 48 ma clifton felsic plutons of the eastern coast plutonic complex cpc that outcrop along the south klondike highway in alaska and british columbia thermal and alternating field step demagnetizing methods yielded stable characteristic remanent magnetization chrm directions for all 29 sites of normal reversed and mixed polarity the chrm resides in single or pseudosingle domain magnetite and or pyrrhotite that is shown to be primary by contact tests with the 47 ma vertical white pass mafic dikes paleopoles from six 56 to 50 ma mean 52 2 ma intermontane belt yukon tanana terrane imb ytt units that cannot be explained by tectonic tilt are compared with nine clustered 59 to 46 ma mean 52 4 ma eastern cpc paleopoles both paleopole populations show nonsignificant poleward northward translation relative to north america imb ytt 3 7 5 3 n cpc 4 3 6 4 s overall 1 2 4 9 s ind

noble gases in ocean waters and sediments noble gases are widely used in studies of the basic properties and dynamics of natural systems including the ocean this chapter describes some of the more extensive applications of noble gases mainly helium isotopes to studies of oceanographic problems they include the modern oceanic circulation paleo oceanography hydrothermal and cold brine systems in the deep ocean and ocean atmosphere gas exchange originally oceanic noble gas studies were focused on geochemical problems such as the question of the existence of excess helium in seawater derived from radioactive decay of the elements of the uranium and thorium series in ocean sediments suess and wanke 1965 bieri et al 1966 after the discovery of mantle primordial helium during the 1960s clarke et al 1969 craig and weiss 1971 craig et al 1975 and 3he derived from decay of tritium in the near surface waters of the ocean jenkins and clarke 1976 large programs were developed to exploit helium isotopes frequently in combination with tritium for studies of water mass formation circulation and variability e g jenkins 1987 schlosser et al 1991 more recent studies started to explore the use of helium isotopes to paleoceanographic objectives these studies build upon the discovery of extraterrestrial helium in deep sea sediments in the early 1960s merrihue 1964 this signal is now being systematically examined for its potential as a tool for investigations of sediment accumulation rates on very long time scales millions of years and their correlation with changes in paleoceanography e g farley 1995 farley and patterson 1995 marcantonio et al 1995 1996 2001 soon after the discovery of mantle helium in seawater noble gases were applied to studies of hydrothermal systems originally these studies were focused on the source of the fluids emanating from hydrothermal vents as well as

seismic attribute based characterization of coalbed methane reservoirs an example from the fruitland formation san juan basin new mexico the fruitland formation of the san juan basin is the largest producer of coalbed methane in the world production patterns vary from one well to another throughout the basin reflecting factors such as coal thickness and fracture and cleat density in this study we integrated conventional p wave three dimensional 3 d seismic and well data to investigate geological controls on production from a thick continuous coal seam in the lower part of the fruitland formation our objective was to show the potential of using 3 d seismic data to predict coal thickness as well as the distribution and orientation of subtle structures that may be associated with enhanced permeability zones to do this we first derived a seismic attribute based model that predicts coal thickness we then used curvature attributes derived from seismic horizons to detect subtle structural features that might be associated with zones of enhanced permeability production data show that the best producing wells are associated with seismically definable structural features and thick coal although other factors e g completion practices and coal type affect coalbed methane production our results suggest that conventional 3 d seismic data integrated with wire line logs and production data are useful for characterizing coalbed methane reservoirs

new taphonomic data of the 1 myr hominin butchery at untermassfeld thuringia germany abstract untermassfeld has provided a butchered bone assemblage and a mode 1 lithic record demonstrating hominin presence at a site which was classically viewed as paleontological this archaeological record was found during fieldwork and surveying in fluvial river banks and low to medium energy channel erosion sediments paleomagnetism and biostratigraphy has yielded an age for this hominin occupation close to the onset of the jaramillo subchron ca 1 07 myr in this paper we present new taphonomic data of the cut marked and hammer related bone material corresponding mainly to large sized herd species i e bison but also from cervids eucladoceros giulii and cervus s l nestii vallonnetensis and megafaunal species i e stephanorhinus hundsheimensis and hippopotamus amphibius antiquus distribution of skeletal elements and bone surface features suggests that this bone assemblage consists of animal remains with different taphonomic origins the assemblage formed during at most two or three sediment laden floods transporting both lithic tools and remains of animals that died of natural causes or were killed by predators the new taphonomic results presented here are important to analyze hominin colonization and adaptation to european mid latitude environments at 1 myr in competition for meat resources with large carnivores i e pachycrocuta brevirostris and panthera onca gombaszoegensis

magnetism and age of the porteau pluton southern coast belt british columbia evidence for tilt and translation the porteau pluton is a variably foliated quartz diorite to granodiorite intrusion in the southern coast belt of the canadian cordillera 49 6 n 123 2 w 40ar 39ar ages are 95 5 ma from biotite and 101 5 0 7 ma from hornblende which together with an earlier u pb zircon age of 100 2 ma indicate that the body was emplaced uplifted and cooled rapidly in mid cretaceous time the rocks contain high coercive force hard remanent magnetizations with unblocking temperatures between 500 and 600 c close to those of ar in hornblende indicating that remanence was acquired at or close to the hornblende plateau age the hard remanence directions have an elongate distribution in agreement with the predictions of m e beck regarding magnetization acquired during tilting uplift and cooling of plutons no part of the distribution agrees with the direction expected from observations from rocks of mid cretaceous age from cratonic north america the elongate distribution defines the axis of tilt 347 east

physical modelling of gelifluction and frost creep some results of a large scale laboratory experiment an experimental slope was constructed in a 5 m 5 m square refrigerated tank the slope was formed of four sections each consisting of regolith soil collected from a distinct bedrock lithology the four lithologies utilized were granite limestone mudstone and slate the slope was subjected to freezing and thawing from the surface downwards water was supplied at the base of the soil during freezing frost heaving and surface downslope soil movement were determined after each of 15 freezing cycles and the profiles of soil movement with depth for each soil type were measured at the end of the 15th cycle the experimental soils were non cohesive those derived from granite and limestone were respectively sandy and gravelly in texture while those derived from mudstone and slate were silt rich mass movement in the granite and limestone soils was due mainly to frost creep and was associated with the growth of needle ice in the mudstone and slate soils gelifluction was dominant as a result of high moisture contents caused by the melting of segregation ice mean per cycle rates of downslope soil transport for the granite limestone mudstone and slate soils were 5 8 cm3 cm 1 6 9 cm3 cm 1 21 2 cm3 cm 1 and 31 2 cm3 cm 1 respectively units referring to the volume of soil passing a unit width of slope per cycle mass movement rates were shown to be strongly related to the silt content of the soils