early human occupation of a maritime desert barrow island north west australia abstract archaeological deposits from boodie cave on barrow island northwest australia reveal some of the oldest evidence for aboriginal occupation of australia as well as illustrating the early use of marine resources by modern peoples outside of africa barrow island is a large 202 km 2 limestone continental island located on the north west shelf of australia optimally located to sample past use of both the pleistocene coastline and extensive arid coastal plains an interdisciplinary team forming the barrow island archaeology project biap has addressed questions focusing on the antiquity of occupation of coastal deserts by hunter gatherers the use and distribution of marine resources from the coast to the interior and the productivity of the marine zone with changing sea levels boodie cave is the largest of 20 stratified deposits identified on barrow island with 20 m 3 of cultural deposits excavated between 2013 and 2015 in this first major synthesis we focus on the dating and sedimentology of boodie cave to establish the framework for ongoing analysis of cultural materials we present new data on these cultural assemblages including charcoal faunal remains and lithics integrated with micromorphology sedimentary history and dating by four independent laboratories first occupation occurs between 51 1 and 46 2 ka overlapping with the earliest dates for occupation of australia marine resources are incorporated into dietary assemblages by 42 5 ka and continue to be transported to the cave through all periods of occupation despite fluctuating sea levels and dramatic extensions of the coastal plain the changing quantities of marine fauna through time reflect the varying distance of the cave from the contemporaneous shoreline the dietary breadth of both arid zone terrestrial fauna and marine species increases after the last glacial maximum and significantly so by the mid holocene the cave is abandoned by 6 8 ka when the island becomes increasingly distant from the mainland coast

advanced application of seismic cone penetration test at complex ground conditions abstract seismic piezocone test scptu is a representative geophysical and geotechnical in situ test which can generate multiple types of independent readings and collect relatively continuous data as well as investigate both vertical and lateral spatial variability for geo characterization this study presents special and advanced applications of scptu towards geotechnical site investigations in west central south carolina us which consists of very complex soil formations and unusual geologic settings the special geologic conditions include apparent gap graded soils calcareous soils cementious bonding desiccation ageing and the dissolutioning of old calcareous sediments santee formation at depths of 40 to 50 meter below grade similar to karstic limestone deposits especially diagenetic processes in the santee carbonate mineral sediments have resulted in caves voids and infilled soft soil zones within the soil matrix at these elevations the data obtained from scptu system are successfully utilized for assessing the various special geologic conditions furthermore a unique example is introduced to represent the powerful application of scptu toward special void detection

radiocarbon dating of charcoal from tropical sequences results from the niah great cave sarawak and their broader implications subsamples of charcoal from a number of different excavation contexts at the early modern human homo sapiens site of niah great cave malaysia were accelerator mass spectrometry ams 14c dated samples were prepared using one of a number of different methods untreated control acid base acid aba and acid base wet oxidation with stepped combustion abox sc after bird et al 1999 the results show that for material younger than 25 ka bp there is little difference between the two chemical pretreatment methods and the control for charcoal beyond 25 ka bp however there are differences of up to 4000 a with abox sc ages being consistently older this is argued to be a more effective pretreatment method for decontaminating charcoal samples prior to radiocarbon dating for radiocarbon dating charcoals greater than 25 ka bp the abox sc pretreatment and combustion approach appears to be the most rigorous method for developing a robust chronological framework for tropical sequences and should be more widely applied in contexts where the material being dated is likely to be ancient the new chronology developed for niah cave based on this technique suggests that the earliest human evidence dates back to at least 45 ka bp and may extend significantly earlier than this based on the recent discovery of lithics 50 cm below the earliest dated charcoal copyright 2008 john wiley sons ltd

fluctuations of the paleomagnetic field during chron c5 as recorded in near bottom marine magnetic anomaly data near bottom magnetic data contain information on paleomagnetic field fluctuations during chron c5 as observed in both the north and south pacific the north pacific data include 12 survey lines collected with a spatial separation of up to 120 km and the south pacific data consist of a single long line collected on the west flank of the east pacific rise epr at 19 s the north pacific magnetic profiles reveal a pattern of linear short wavelength 2 to 5 km anomalies tiny wiggles that are highly correlated over the shortest 3 8 km to longest 120 km separations in the survey magnetic inversions incorporating basement topography show that these anomalies are not caused by the small topographic relief the character of the near bottom magnetic profile from anomaly 5 on the west flank of the epr formed at a spreading rate more than twice that of the north pacific displays a remarkable similarity to the individual and stacked lines from the north pacific survey area over distances corresponding to 1 m y 19 lows in the magnetic anomaly profile can be correlated between the north and south pacific lines modeling the lows as due to short polarity events suggests that they may be caused by rapid swings of the magnetic field between normal and reversed polarities with little or no time in the reversed state owing to the implausibly high number of reversals required to account for these anomalies and the lack of any time in the reversed state we conclude that the near bottom signal is primarily a record of paleointensity fluctuations during chron c5 spectral analysis of the north pacific near bottom lines shows that the signal is equivalent to a paleointensity curve with a temporal resolution of 40 to 60 kyr while measurements of the smallest separations of correctable dips in the field suggest a temporal resolution of 36 kyr

differential burning recrystallization and fragmentation of archaeological bone abstract this paper presents research on the conditions under which progressive levels of burning may occur to archaeological bone and how burning damage changes bones crystal structure and susceptibility to fragmentation a k a friability experiments were conducted to simulate common patterns of high temperature bone diagenesis and fragmentation previously documented in paleolithic shelter sites bones buried up to 6 cm below the coal beds of the experimental fires were carbonized but calcination occurred only with direct exposure to live coals analysis by infra red spectroscopy reveals that marked changes in crystallinity accompany the macroscopic transformations in colour and friability of modern fire altered bone specifically a monotonic non linear decrease in mean fragment length across six colour categories was observed when samples were agitated or trampled and a concordant decline in bone identifiability first with respect to skeletal element and ultimately the recognizability of bone tissue itself these findings help qualify the behavioural and taphonomic implications of fragmented burned bones in archaeological sites especially with regard to potential stratigraphic associations between artefacts and hearth features in sites and the intensity of space use by human occupants the identification of burning damage on archaeological bone is a separate issue however it was found that the molecular signatures of recrystallization in modern burned bones partly overlap with recrystallization caused by weathering after only 1 to 2 years of exposure in an arid setting and by partial fossilization of archaeological bones over the long term while infra red and x ray diffraction techniques effectively describe heat induced changes in modern bone mineral and are an important aid for modelling diagenetic processes these techniques did not reliably identify burning damage to archaeological bones cross referencing readily visible colour phases with hcl insoluble fraction data proves much more effective and economically feasible for the latter purpose

deep tow magnetic anomaly study of the pacific jurassic quiet zone and implications for the geomagnetic polarity reversal timescale and geomagnetic field behavior 1 the jurassic quiet zone jqz is a region of low amplitude magnetic anomalies whose distinctive character may be related to geomagnetic field behavior we collected deep tow magnetic profiles in pigafetta basin western pacific where previous deep tow data partially covered the jqz sequence our goals were to extend the survey through the jqz examine anomaly correlations and refine a preliminary geomagnetic polarity timescale gpts model we collected a series of closely spaced profiles over anomaly m34 and ocean drilling program hole 801c to examine anomaly correlation in detail one profile in between previous profiles and two long profiles extending the survey deeper into the jqz anomaly features can be readily correlated except in a region of low amplitude short wavelength anomalies in the middle of the survey area low amplitude zone or laz the small multiprofile surveys demonstrate anomaly linearity implying that surrounding anomalies are also linear and likely result from crustal recording of geomagnetic field changes we constructed a gpts model assuming that most anomalies result from polarity reversals the polarity timescale is similar to the polarity sequences from previous studies but its global significance is uncertain because of problems correlating anomalies in the laz and the ambiguous nature of the small jqz anomalies overall anomaly amplitude decreases with age into the laz and then increases again implying low geomagnetic field strength perhaps related to a rapidly reversing field other factors that may contribute to the laz are interference of anomalies over narrow crustal polarity zones and poorly understood local tectonic complexities

45 610 52 160 years of site and landscape occupation at nawarla gabarnmang arnhem land plateau northern australia we present bayesian modelling on a long sequence of radiocarbon ages from the archaeological site of nawarla gabarnmang central arnhem land plateau northern australia a horizon of wind borne sediments containing flaked stone artefacts and charcoal commencing 45 610 cal bp the young end of the modelled boundary age range which extends beyond the limit of the calibration curve with a median modelled age of 48 500 cal bp signals the onset of aeolian mobilisation of fine sands and silts across the landscape and re deposition within the site at a time synchronous with the first evidence of people this earliest cultural horizon stratigraphic unit 4 contains 509 stone artefacts and is marked by a contemporaneous sedimentary break from underlying culturally sterile sediments consisting of disintegrating roof fall and in situ sandstone and quartzite to overlying culturally rich wind blown sand the new radiocarbon ages and wind blown sediments together provide evidence for the commencement of noticeable landscape burning on the arnhem land plateau c 48 500 cal bp suggesting an intensification of landscape management practices at the summit of the arnhem land plateau some 10 000 e15 000 years after the lowest dense band of artefacts phase 2 at madjedbebe on the floodplains 90 km to the north these results have ramifications for the structure and timing of the spread of people across australia and the extinction of megafauna in sahul

a 28 000 year old excavated painted rock from nawarla gabarnmang northern australia we report new archaeological excavations from northern australia revealing part of a charcoal design likely to be c 28 000 years old and chrono stratigraphically constrained within the period 15 600 45 600 cal bp on a small rock slab fallen from the ceiling at the rockshelter of nawarla gabarnmang in jawoyn country arnhem land this represents the oldest confirmed pictograph in australia

holocene palaeohydrology of the east alligator river for application to mine site rehabilitation northern australia abstract as a contribution to the estimation of extreme floods and rainfall palaeofloods in the east alligator river in tropical australia were examined to derive estimates of palaeodischarges and their frequency nine extreme floods have occurred over 8400 years in a non stationary series the youngest five of which are stationary and the youngest three of which occurred during wet periods produced by variations of the southern oscillation index soi modulated by the pacific decadal oscillation pdo the magnitudes of these floods are similar with one possible exception in 2007 ce the extreme floods in the region lie close to or above the australian flood envelope curve showing that floods larger than the expected are possible their magnitudes also approximate the probable maximum flood pmf but with a much higher frequency than expected the annual exceedance probability aep of the palaeofloods is 0 3 which may also be the aep for the rainfall these results will be used as input to the design of an artificial landform at the ranger uranium mine within the east alligator catchment that has to last for 10 000 years the 2007 ce flood was probably the most extreme flood and associated rainfall likely to occur in the vicinity of ranger under the current climate and will occur in the future along with climate change because of the uncertainties associated with projections of future extremes the best design rainfall aep for the ranger landform is 0 3

early human occupation at devil s lair southwestern australia 50 000 years ago abstract new dating confirms that people occupied the australian continent before the earliest time inferred from conventional radiocarbon analysis many of the new ages were obtained by accelerator mass spectrometry 14c dating after an acid base acid pretreatment with bulk combustion aba bc or after a newly developed acid base wet oxidation pretreatment with stepped combustion abox sc the samples charcoal came from the earliest occupation levels of the devil s lair site in southwestern western australia initial occupation of this site was previously dated 35 000 14c yr b p whereas the aba bc ages are indistinguishable from background beyond 42 000 14c yr b p the abox sc ages are in stratigraphic order to 55 000 14c yr b p the abox sc chronology suggests that people were in the area by 48 000 cal yr b p optically stimulated luminescence osl electron spin resonance esr ages u series dating of flowstones and 14c dating of emu eggshell carbonate are in agreement with the abox sc 14c chronology these results based on four independent techniques reinforce arguments for early colonization of the australian continent

redating the onset of burning at lynch s crater north queensland implications for human settlement in australia lynch s crater preserves a continuous high resolution record of environmental changes in north queensland this record suggests a marked increase in burning that appears to be independent of any known major climatic boundaries this increase is accompanied or closely followed by the virtually complete replacement of rainforest by sclerophyll vegetation the absence of any major climatic shift associated with this increase in fire frequency therefore has been interpreted as a result of early human impact in the area the age for this increase in burning on the basis of conventional radiocarbon dating was previously thought to be approximately 38000 c 14 yr bp supporting the traditional model for human arrival in australia at 40 000 c 14 yr bp here we have applied a more rigorous pre treatment and graphitisation procedure for radiocarbon dating samples from the lynch s crater sequence these new dates suggest that the increase in fire frequency occurred at 45 000 c 14 yr bp supporting the alternative view that human occupation of australia occurred by at least 45 000 55 000 cal yr bp copyright c 2001 john wiley sons ltd

geomagnetic polarity reversal model of deep tow profiles from the pacific jurassic quiet zone the jurassic magnetic quiet zone jqz contains magnetic lineations but their low amplitudes make correlation and interpretation difficult part of the problem is the separation of source and sensor for old deep ocean crust we increased anomaly amplitudes by collecting magnetic data along two deep tow profiles over western pacific jqz lineations a magnetic polarity reversal timescale was constructed by matching deep tow anomalies with a simple rectangular block magnetization model for oceanic crust the polarity sequence covers 11 m y 156 167 5 ma and contains 88 pre m29 polarity chrons extending to chron m41 a limitation of this model is its poor representation of the oldest anomalies upward continued to sea level on deep tow profiles these anomalies have both long and short wavelength components but only the latter are easily modeled on a datum close to the source an alternative polarity model was constructed to match the anomalies upward continued to sea level this model retains only 44 of the deep tow model polarity chrons because of short wavelength attenuation by upward continuation because of the inferred periods and magnetization contrasts we think many of the short wavelength anomalies represent paleofield intensity fluctuations in contrast polarity reversals have been documented by prior magnetostratigraphic work for the younger part of the timescale covered by our model thus our data may show a transition from a geomagnetic field behavior dominated by intensity fluctuations to one dominated by reversals

new radiocarbon dating of the transition from the middle to the upper paleolithic in kebara cave israel the middle to upper paleolithic transition mp up transition is considered a major technological and cultural threshold at the time when modern humans spread out of africa expanded from the levant into europe and possibly into central and northern asia the dating of this techno cultural transition has proved to be extremely difficult because it occurred sometime before 40 000 radiocarbon years before present 14c years bp which is close to the end of the effective dating range of radiocarbon other dating methods such as thermoluminescence tl or electron spin resonance esr are not sufficiently precise to date the recorded archaeological mp up transition in the levant here we report a consistent set of stratified radiocarbon ages on freshly excavated charcoal from kebara cave mt carmel israel that span the late middle paleolithic mp and early upper paleolithic eup this study applied novel strategies to improve sample preparation techniques and data analysis to obtain high resolution radiocarbon models from this study it is proposed that the mp up transition for this site can be placed immediately after 45 200 700 14c years bp and before 43 600 600 14c years bp or from 49 48 to 47 46 radiocarbon calibrated years before present years cal bp

effect of cementation on the small strain parameters of sands natural cementation affects the properties of soils the interpretation of in situ and laboratory test results and the selection of criteria for geotechnical design in this paper published exper

an alternative explanation for intermediate wavelength magnetic anomalies harrison and carle this issue and others have examined very long profiles of the magnetic field and have calculated one dimensional power spectra in these they expect to see but do not find a minimum in power at intermediate wavelengths between 65 and 150 km conventional one dimensional models of the field predict very little power in this band which lies between the spectral peaks arising from sources in the crust and the core mantle sources or high intensity long wavelength magnetizations have been proposed to account for the observations an alternative more plausible explanation is that one dimensional spectra of two dimensional fields contain contributions from wavenumbers in the perpendicular i e nonsampled direction unless the seafloor spreading anomalies are perfectly lineated at right angles to the profile some low wavenumber energy must be attributed to this effect we propose that such directional aliasing is a major factor in the power spectra to support this idea we discuss theoretical models and analyze a large scale marine survey

last glacial megafaunal death assemblage and early human occupation at lake menindee southeastern australia abstract the tedford subfossil locality at lake menindee preserves a diverse assemblage of marsupials monotremes and placental rodents of the 38 mammal taxa recorded at the site almost a third are of extinct megafauna some of the bones are articulated or semi articulated and include almost complete skeletons indicating that aeolian sediments rapidly buried the animals following death new optical ages show the site dates to the early part of the last glacial 55 700 1300 yr weighted mean age this is close to the 51 200 39 800 yr australia wide extinction age for megafauna suggested by roberts et al 2001 science 292 1888 1892 but like all previous researchers we cannot conclusively determine whether humans were implicated in the deaths of the animals although an intrusive hearth at the site dating to 45 100 1400 yr ago is the oldest evidence of human occupation of the darling river no artifacts were identified in situ within the sub fossil bearing unit non anthropogenic causes such as natural senescence or ecosystem stress due to climatic aridity probably explain the mortality of the faunal assemblage at lake menindee

simulation of downhole and crosshole seismic tests on sand using the hydraulic gradient similitude method a method of simulating downhole and crosshole seismic shear wave tests in a model under controlled stress conditionsis described the downhole and shear wave in horizontal plane sh crosshole shear waves are generated and received along the principal stress axes using piezoceramic bender elements the k0in situ stress conditions including loading and unloading stress paths are simulated by the hydraulic gradient similitude method which allows high stresses simulating field conditions to be obtained the horizontal stress during the tests is directly measured by a lateral total stress transducer the test data are used to evaluate various published empirical equations that relate shear wave velocity and soil stress state it is found that although the various empirical equations can predict the in situ shear wave velocity profile reasonably well only the equation that relates the shear wave velocity to the individual principal stresses in the directions of wave propagation and particle motion can pred

source of tiny wiggles in chron c5 a comparison of sedimentary relative intensity and marine magnetic anomalies 1 in addition to the well established pattern of polarity reversals short wavelength fluctuations are often present in both sea surface data tiny wiggles and near bottom anomaly data while a high degree of correlation between different geographical regions suggests a geomagnetic origin for some of these wiggles anomaly data alone cannot uniquely determine whether they represent short reversals or paleointensity variations independent evidence from another geomagnetic recording medium such as deep sea sediments is required to determine the true nature of the tiny wiggles we present such independent evidence in the form of sedimentary relative paleointensity from chron c5 we make the first comparison between a sedimentary relative paleointensity record odp site 887 at 54 n 148 w and deep tow marine magnetic anomaly data 43 n 131 w bowers et al 2001 for chron c5 the sediment cores are densely sampled at 2 5 kyr resolution the inclination record shows no evidence for reverse intervals within the 1 myr long normal chron c5n 2n rock magnetic measurements suggest that the primary magnetic carrier is pseudo single domain magnetite we choose a partial anhysteretic magnetization parm as our preferred normalizer and the resulting relative paleointensity record is used as input to a forward model of crustal magnetization we then compare the results of this model with the stacked deep tow anomaly records the two records show a significant degree of correlation suggesting that the tiny wiggles in the marine magnetic anomalies are likely produced by paleointensity variations an analysis of our sampling density suggests that if any reverse intervals exist at this site they are likely to be 5 kyr in duration furthermore we suggest that reverse intervals during chron c5n 2n documented in other locations are unlikely to be global

problems with radiocarbon dating the middle to upper palaeolithic transition in italy abstract radiocarbon dating of material from late pleistocene archaeological sites is challenging small amounts of modern 14c labelled contamination will significantly affect the reliability of dates from the period producing erroneous results recent developments in sample pre treatment chemistry have shown that problems in reliable age determination during this period are surmountable in this paper we provide an example of one such case from the middle to upper palaeolithic transitional site of the grotta di fumane in northern italy we ams dated two fractions of the same charcoal samples derived from a series of superimposed mousterian aurignacian and gravettian levels excavated at the site one fraction was treated using the routine acid base acid aba method the other with the more rigorous acid base oxidation stepped combustion abox sc method the latter method produced consistently older and almost certainly more reliable results the eruption of the known age campanian ignimbrite from the phlegrean fields near present day naples at 39 3 ka yr bp seals ulluzzian and proto aurignacian levels in the south of italy equivalent cultural levels are present at fumane and the results obtained with the abox sc methods are consistent with the ages inferred for sites in the south of italy based on the presence of the campanian ignimbrite new results from a sample found beneath the campanian ignimbrite at the russian site of kostenki obtained using both the aba and abox sc methods are also presented they support the conclusion reached at fumane by demonstrating that in many cases the abox sc treatment effectively removes contamination where the aba treatment does not the results of the work offer a sobering examination of the problems inherent in the current radiocarbon database relating to the period and highlight the dangers of an uncritical use of the corpus of 14c results obtained over the last few decades based on our results we predict that more than 70 of the 53 previously available determinations from fumane are erroneously young a way forward is suggested using these improved chemical preparation methods applying analytical methods to characterise the material dated and testing existing site chronologies to establish which previous determinations are liable to be inaccurate

coherence of signals from magnetometers on parallel paths during a recent marine magnetic survey of the juan de fuca rise two magnetometers were towed near the seafloor one about 300 m above the other to understand how to interpret the records we investigate a simple statistical model two magnetometers moving on parallel paths above a statistically stationary source with known spectrum magnetometers on paths normal to perfectly lineated magnetic anomalies will measure signals that have unit coherence at all wavelengths departure of the system from this ideal state can be diagnosed by a lower coherence and something about the across track structure can be learned from the shape of the coherence spectrum we calculate the power and cross spectra of the profile signals in terms of the two dimensional power spectrum of the field just above the source region hence we obtain the coherence and phase spectra for the special case of a white source spectrum we find surprisingly high coherences a set of inequalities between the spectral estimates is derived and can be used to check the consistency of the measured signals with the model assumptions the theory is applied to a magnetic traverse of the juan de fuca rise when two near bottom magnetometers were deployed the key results are these in the wavelength range above about 1 km the observed coherency is substantially higher than that from the disordered field model consistent with the highly lineated structures observed at the surface over all ocean ridge systems on scales between 500 m and 1 km the coherence falls to levels indistinguishable from those given by an isotropic flat spectrum implying that on these scales there is little or no across track lineation this finding means that the resolution of paleomagnetic field behavior based on seafloor data in this area is no better than 36 000 years

the human colonisation of australia optical dates of 53 000 and 60 000 years bracket human arrival at deaf adder gorge northern territory the date at which people entered australia has important implications for the debate on modern human origins thermoluminescence dates of 50 60 ka reported for initial occupation of the malakunanja ii site in northern australia have been used as a means of calibrating the rate of mitochondrial and nuclear dna evolution in modern humans optical dating of unburnt quartzose sediments from a rock shelter site nauwalabila i lindner site in deaf adder gorge 70 km south of malakunanja ii provides new evidence for the timing of the colonisation of the continent optical dates were determined for several stratigraphic levels within a 3 m deep excavation in which flaked stone artefacts and ground pigments were found in primary depositional setting the lowest human occupation levels are bracketed by dates of 53 4 5 4 ka and 60 3 6 7 ka while the upper levels show good agreement between optical and calibrated 14c age estimates high quality haematite with ground facets and striations is associated directly with the 53 ka level and indicates the use of pigments by these early australians the optical dates independently confirm evidence for the colonisation of northern australia shortly after 60 ka and should be seen in the context of this region as having been a likely entry route for the first human movements into sahul

small strain stiffness shear wave velocity and soil compressibility abstractthe small strain shear modulus depends on stress in uncemented soils in effect the shear wave velocity which is often used to calculate shear stiffness follows a power equation with the mean effective stress in the polarization plane vs m 1 kpa where the factor is the velocity at 1 kpa and the exponent captures the velocity sensitivity to the state of stress the small strain shear stiffness or velocity is a constant fabric measurement at a given state of stress however parameters and are determined by fitting the power equation to velocity measurements conducted at different effective stress levels so changes in both contact stiffness and soil fabric are inherently involved therefore the and parameters should be linked to soil compressibility cc compiled experimental results show that the factor decreases and the exponent increases as soil compressibility cc increases and there is a robust inverse relationship between and for all sediments 0 73 0 27 log

sedimentology and depositional environments of middle eocene terrigenous carbonate strata southeastern atlantic coastal plain usa abstract basin margin sediments of middle eocene age in the savannah river site area consist of five terrigenous carbonate lithofacies quartz sand calcareous quartz sand sandy carbonate muddy carbonate and a transitional lithofacies that ranges from sandy muddy carbonate to calcareous mud the middle eocene sediment package which includes calcareous parts of the upper congaree warley hill and santee formations dips southeast at 4 7 m km and thickens from 2 m at its updip edge to 95 m downdip the presence of glauconite and a diverse faunal assemblage in all lithofacies suggests deposition in clear well oxygenated open marine waters of normal salinity on the inner to middle shelf with periods of marginal marine nearshore and deltaic influence coarse grained terrigenous sand and calcareous sand deposited in higher energy nearshore environments occur near the updip limit fine grained terrigenous mud calcareous mud and sandy and muddy carbonate are located downdip and accumulated in quieter water conditions on the inner and middle shelf the transition from terrigenous to carbonate sediment occurs near the updip limit in a narrow zone less than 5 km wide three depositional sequences which contain transgressive and highstand system tracts are recognized within the middle eocene calcareous interval one is assigned to the upper congaree formation ta 3 5 3 6 cycles the main control on areal distribution hill formation ta3 4 cycle and one to the santee formation ta 3 5 3 6 cycles the main control on areal distribution of facies was depositional environment which was controlled primarily by sea level eustasy and the amount rate and locus of terrigenous influx in updip areas however sediment distribution and thickness were also influenced by middle eocene growth faulting diagenetic pathways vary with facies type but generally include 1 marine phreatic boring of skeletal fragments by algae and fungi grain micritization and radially fibrous cementation and 2 freshwater phreatic inversion of high mg calcite to low mg calcite dissolution of aragonitic allochems formation of moldic porosity precipitation of syntaxial calcite overgrowths on echinoderms formation of calcite spar and isopachous calcite cement neomorphism of micrite to microspar and pseudospar precipitation of opal ct lepispheres replacement of mollusk shells by chalcedony and precipitation of zeolites within secondary moldic pores quartz rich facies have high interparticle porosity and excellent permeability mud rich facies have low to moderate porosity and permeability owing to the isolation of moldic and vug pores

deposition models for chronological records abstract long term sedimentary sequences provide a wealth of useful information for research into the palaeo environment especially in relation to past climate change shorter records provide similar information in many archaeological contexts however if such records are to be used to provide precise timing of events and more critically the relative timing between different records methods are needed to provide accurate and precise age depth models for these sequences given the imprecision of individual calibrated radiocarbon determinations it is necessary to use the information we have about the deposition process to refine our chronologies and also to provide interpolation between dated levels in any sequence even with layer counted chronologies the uncertainties are sometimes hard to quantify this paper outlines a range of bayesian models for deposition which have been implemented in the computer programme oxcal these models can be used to combine information from the sediments themselves with radiocarbon or other direct dating information such models have the potential to integrate information between different records and provide a coherent chronology on which to base environmental or archaeological research