estimating relative ages from iron oxide total iron ratios of soils in the western po valley italy abstract nineteen samples were collected from deeper layers of as many terraces forming agesequences in five basins most samples were collected at depths of 1 m or more with some below 3 m soils at the sample sites were tentatively identified as alfisols entisols or inceptisols total amounts of iron and the amounts extractable by dithionite and by oxalate were determined for the 19 samples redness ratings were calculated from sample colors and related to amounts of extractable iron by regression mineralogies of the fine sand silt and clay fractions were also determined the percentage of the total iron fe t extracted by dithionite fe d minus the amount extracted by oxalate fe o increased gradually with ages of the terraces which range from early middle pleistocene to upper pleistocene holocene these percentages are independent of the total amounts of iron in the samples and of the general lithology of a basin such ratios thus promise to be useful in estimating relative ages especially where time sequences exist mineralogies of the samples were consistent with relative ages of terraces as estimated from the ratios of iron in different forms so were the redness ratings the regression of extracted iron on redness ratings suggests that colors can be used as preliminary field indicators of relative ages of terraces without time sequences

a soil chronosequence in northwestern italy morphological physical and chemical characteristics abstract a chronosequence of soils developed on fluvial terraces dating from lower middle pleistocene to upper upper pleistocene was studied to identify the morphological physical and chemical soil properties most sensitive to soil development and to further test the usefulness of iron oxides as indicators of relative age a relative horizon distinctness rhd index and the buntley westin and hurst colour indices clearly reflected differences in soil development with age among physical characteristics clay content and aggregation obtained by comparison of clay dispersion before and after removal of cementing agents were most efficient in indicating differences in duration of pedogenesis cation exchange capacity as related to clay content was the chemical property most useful to distinguish soils of different terraces iron oxide ratios were again useful as indices of soil development

effect of catchment scale subsurface mixing on stream isotopic response a 3 8 ha watershed on the west coast of new zealand was instrumented with suction lysimeters and automatic water samplers to determine the relationship between subsurface isotopic and chemical concentrations to those of rainfall and resulting streamflow a t test showed that 2 represented a significant difference between successive sample deuterium values eleven rainfall episodes were subdivided into two categories 1 two events where stream isotopic composition did not deflect 2 from prestorm values and 2 four events which demonstrated new water flushing detailed analysis of one 47 mm rainfall 9 8 mm runoff event showed that old water dominated stream water exiting the watershed by 90 using a standard two component hydrograph separation for deuterium corroborated by cl and electrical conductivity three component hydrograph separation indicated that 12 16 was in the form of soil water with 5 as on channel precipitation and 80 groundwater analysis of over 1000 water samples revealed systematic trends in soil water and groundwater isotopic composition both in a downslope and downprofile direction between storm suction lysimeter deuterium data showed a systematic dampened response to temporally variable rainfall deuterium concentrations multivariate cluster analysis revealed three distinct soil water groundwater groupings with respect to soil depth and geographic position within the watershed within storm suction lysimeter sampling preserved similar groupings indicating that the subsurface reservoir is poorly mixed on short time scales understanding subsurface mixing response to rainfall should greatly improve models of episodic stream response and partitioning of storm flow into waters of different age

correlation and dating of quaternary alluvial fan surfaces using scarp diffusion great interest has recently been focused on dating and interpreting alluvial fan surfaces as a complement to the radiometric methods often used for surface exposure dating this paper illustrates a rapid method for correlating and dating fan surfaces using the cross sectional shape of gullies incised into fan surfaces the method applies a linear hillslope diffusion model to invert for the diffusivity age t m2 using an elevation profile or gradient slope profile gullies near the distal end of fan surfaces are assumed to form quickly following fan entrenchment scarps adjacent to these gullies provide a measure of age the method is illustrated on fan surfaces with ages of approximately 10 ka to 1 2 ma in the arid southwestern united states two areas of focus are death valley california and the ajo mountains piedmont arizona gully profile morphology is measured in two ways by photometrically derived gradient slope profiles and by ground surveyed elevation profiles the t values determined using ground surveyed profiles are more consistent than those determined using photo derived t values however the mean t values of both methods are comparable the photometric method provides an efficient way to quantitatively and objectively correlate and relatively date alluvial fan surfaces the t values for each surface are determined to approximately 30 50 accuracy

amino acid racemization geochronology of reworked quaternary mollusks on u s atlantic coast beaches implications for chronostratigraphy taphonomy and coastal sediment transport approximately 200 shells primarily mercenaria from 21 beach sites between new jersey and florida have been analyzed for the extent of racemization epimerization of their fossilized amino acids the greatest concentration of sites is in north carolina in regions least affected by human modification of natural beach sediment transport processes these results can be used to estimate the frequency of age mixing of pleistocene shell material in holocene depositional environments selected shells have also been dated by 14c conventional and or ams to provide direct calibration of the amino acid epimerization ratios shell taphonomic characteristics particularly color can be qualitatively related to apparent ages data for shell fragmentation combined with amino acid age estimates provide insights into probable transport distances of reworked shells shells with apparent pleistocene ages have epimerization values equivalent to those seen in onshore exposures of pleistocene coastal units amino acid epimerization measurements are a comparatively rapid and inexpensive chronologic tool for use in taphonomic and sediment shell transport studies paired amino acid 14c analyses on single shells provide insights into geochemical alteration of shells and permit modelling of the residence time of shells on beaches greater numbers of analyses at each site are needed before statistically valid estimates of age mixing can be obtained but the apparent distribution of pleistocene shells on atlantic coast beaches appears to be related to the distribution of pleistocene units in the shoreface and inner shelf and the thickness of holocene sedimentary cover in specific areas these observations provide useful criteria for the evaluation of possible age mixing of shells collected at outcrops of pleistocene units in the coastal plain

successive foraminiferal faunas and inferred palaeoenvironments associated with the postglacial holocene marine transgression gulf st vincent south australia gulf st vincent is one of a pair of elongate triangular shallow water embayments into the southern coast of continental australia from the southern floor of this embayment within a shallow basi

pedostratigraphic models for alluvial fan deposits a tool for interpreting ancient sequences this paper reviews the scattered literature on quaternary arid type alluvial fan soil sequences and presents a series of model stratigraphies these are primarily influenced by the degree of entrenchment and by climatic controls these models are used to interpret well exposed miocene fan deposits from the madrid basin central spain

the impact of quaternary sea level and climatic change on coastal alluvial fans in the cabo de gata ranges southeast spain conventionally a fall in base level is seen as stimulating incision into the distal zones of alluvial fans in the cabo de gata ranges of southeast spain evidence exists to the contrary two sets of quaternary coastal alluvial fans demonstrate the interaction between climatically driven variations in the supply of sediment and eustatically driven changes in base level the fans are supplied from miocene volcanic terrain within which no evidence can be found for major tectonic deformation during the period of fan development the evolution of the east coast fans has been affected by variations in sediment supply and changes in sea level the west coast fans were buffered from the effects of changes in sea level by coastal barriers three phases of past sedimentation can be identified on the fans these can be differentiated on the basis of field observations of soil profiles particularly colour of the b horizons and accumulation of caco3 and laboratory analyses of sequential iron oxide extractions and magnetic mineral properties the two earlier major sedimentation phases were coincident with global glacials ca 135 ka and ca 85 10 ka based on the stratigraphy and uranium thorium dating of the coastal sediments high sea levels during the intervening interglacial and during the holocene caused erosion of the distal zones of the east coast fans which led to channel incision into the fan surfaces on the west coast fans no such incision occurred simply proximal incision by small fanhead trenches the youngest relatively minor phase of fan sedimentation has occurred during the holocene these contrasting contexts have produced differing styles of fans with telescopic fan morphology on the east coast and stacked morphology on the west coast fans the differences are reflected in the fan profiles with steeper gradients dominating the east coast fans and extensive lower gradient distal surfaces on the west coast fans fan morphometry based on analysis of the residuals from drainage area to fan area and gradient regressions also differentiates between the fan contexts the fan building phases appear to be controlled proximally by climatically driven pulses of sediment supplied to the fans these occurred during global glacials coincident with low sea levels and caused fan progradation onto the exposed foreshore the intervening global interglacials were times of little fan sedimentation and on the east coast where high sea levels were able to erode the fan toes deep through fan dissection ensued

aminostratigraphy of quaternary coastal sequences in southern australia an overview abstract since the early 1980s amino acid racemisation reactions have been applied to the dating of quaternary coastal deposits in australia sequences of middle pleistocene age or younger have received the greatest attention amino acid racemisation has been applied as a relative and numeric dating method as well as for identifying remanie fossils and in delineating the spatial distribution of some fossil mollusc species the method has also been used to verify the radiocarbon ages of fossil molluscs from interstadial sediments it has also been used in studies of coastal neotectonics and in comparisons with other dating methods e g electron spin resonance and thermoluminescence the most reliable results are from replicate analyses of the hinge region of well preserved and diagenetically unmodified fossil bivalve molluscs from deeply buried situations i e 1 m molluscs have been dated from a range of sites around the southern australian coastline and include specimens of plio pleistocene age and from middle pleistocene oxygen isotope stage 7 ca 220 ka bp late pleistocene substage 5e ca 125 ka bp interstadial stage 3 45 to 30 ka bp last glacial stage 2 ca 18 ka bp and holocene sequences amino acid racemisation dating of the australian quaternary coastal record has 1 confirmed the widespread occurrence of last interglacial coastal strata and allowed their correlation with sequences of equivalent age from the northern hemisphere 2 identified strata of penultimate interglacial age and 3 confirmed the interstadial age of marine strata stage 3 in gulf st vincent south australia aminostratigraphic studies of the southern australian quaternary coastal record also indicate that sea levels during the penultimate interglacial stage 7 may have been higher than otherwise predicted on the basis of the oxygen isotope record

soil moisture content estimation using ground penetrating radar reflection data abstract ground penetrating radar gpr reflection travel time data were used to estimate changes in soil water content under a range of soil saturation conditions throughout the growing season at a california winery data were collected during three data acquisition campaigns over an 80 by 180 m area using 100 mhz surface gpr antennas gpr reflections were associated with a thin low permeability clay layer located 0 8 1 3 m below the ground surface that was identified from borehole information and mapped across the study area field infiltration tests and neutron probe logs suggest that the thin clay layer inhibited vertical water flow and was coincident with high volumetric water content vwc values the gpr reflection two way travel time and the depth of the reflector at the borehole locations were used to calculate an average dielectric constant for soils above the reflector a site specific relationship between the dielectric constant and vwc was then used to estimate the depth averaged vwc of the soils above the reflector compared to average vwc measurements from calibrated neutron probe logs over the same depth interval the average vwc estimates obtained from gpr reflections had an rms error of 0 018 m3 m 3 these results suggested that the two way travel time to a gpr reflection associated with a geological surface could be used under natural conditions to obtain estimates of average water content when borehole control is available and the reflection strength is sufficient the gpr reflection method therefore has potential for monitoring soil water content over large areas and under variable hydrological conditions

glacial lowstand deposits on the outer continental shelf of southeastern australia vibracores collected from water depths of 130 to 150 m on the outer continental shelf of southeastern australia contain evidence for several cycles of shallow marine deposition one of these vibracores 112 vc 134 lat 33 24 s long 151 58 e preserves evidence for the last three glacial lowstands as inferred from radiocarbon dating amino acid racemization and fossil mollusc assemblages the core contains the inner shelf molluscs pecten fumatus placamen placidium and tawera gallinula which today live in water depths of 10 to 50 m in the cool waters of southern australia radiocarbon dating and amino acid racemization analyses on multiple valves of p fumatus in the core indicate three distinct age groupings of fossil molluscs 1 those younger than 20 000 yr b p 2 those with minimum ages of about 100 000 yr and 3 those with minimum ages of about 200 000 yr we assign these sediments to oxygen isotope stages 2 6 and 8 respectively the core contains the first shallow marine lowstand deposits to be recovered from the shelf of eastern australia these deposits constrain the last three glacial lowstands on this margin to water depths 130 m below present sea level

the geomorphological evolution of a wave dominated barrier estuary burrill lake new south wales australia abstract the geomorphological evolution of the holocene wave dominated barrier estuary at burrill lake on the new south wales coast australia has been investigated using a combination of seismic stratigraphy and lithostratigraphic analysis of vibracores collected from the back barrier estuarine environment a combination of radiocarbon and aspartic acid racemisation derived ages obtained on holocene fossil molluscs and the thermoluminescent signal in remnant the last interglacial barrier provides the chronological framework for this investigation results from this paper show that the barrier estuary occupies a relatively narrow

the last interglacial shoreline in australia a review abstract marginal marine strata of last interglacial age occur in a range of morphostratigraphic settings around the australian coastline the lithofacies are similar to their holocene equivalents but are partly lithified elevated and laterally displaced inland uranium series ages for corals and molluscs from widely separated localities around the australian coastline are generally in accord with the accepted age for oxygen isotope substage 5e 125 000 10 000 bp the value generally accepted for the last interglacial maximum amino acid racemisation has principally been applied to correlation of sequences with benchmark sites dated by the uranium series method elevations of preserved last interglacial shorelines do not support the notion that australia is a stable continent significant neotectonic anomalies include cape cuvier 10 5 m fleurieu peninsula 6 m the coorong coastal plain 10 m and tasmania 32 m each indicating contrasting degrees of local uplift the tasmanian sequences are the highest occurrence on the australian continent and have been attributed to uplift as a result of mantle hotspot processes with the exception of these tectonically uplifted sites the height of the last interglacial sea surface around the australian coastline is consistently below the 6 m level globally attributed to this high sea level stand in australia the most consistent datum is from western eyre peninsula where a level 2 m above present mean sea level is ubiquitous the more southerly limit of coral growth and wider distribution of subtropical molluscan fauna are in accordance with warmer ocean waters during substage 5e approximately 2 c the extent of racemisation in molluscan fossils from southern australia also excludes the possibility of a more equable latitudinal distribution of mat during substage 5e

role of pedogenesis in distribution of magnetic susceptibility in two california chronosequences abstract pedons from two soil chronosequences from coastal terraces in northern california were examined and sampled and samples were analyzed to determine the contribution of normal pedogenic processes to the distribution of mass magnetic susceptibility in soils commonly distribution in soils and the formation of susceptibility enhancement in near surface soil layers are attributed in large part to the in situ conversion of nonferrimagnetic iron oxides and oxyhydroxides to microcrystalline ferrimagnetic minerals solubilization of fe 2 and subsequent precipitation also contribute to enhancement we show that enhancement occurred throughout the eluvial and in some illuvial horizons to depths as great as 100 cm in these soils eluvial horizon and enhancement increased with increasing soil age the enhancement of magnetic susceptibility resulted from the accumulation of pedogenic ferrimagnetics and the preferential accumulation of both inherited magnetite and pedogenic maghemite we use the differential solubility of inherited magnetite and maghemite in citrate bicarbonate dithionite and x ray diffraction to distinguish between the two minerals although magnetite is a relatively more durable soil mineral it did weather and the total amount of magnetite decreased as soil age increased sonicated sand grains free of clay or fe coatings contributed to susceptibility enhancement silt and clay sized grains provided the larger part of illuvial horizon illuviation to or formation of clay sized ferrimagnetic particles in illuvial horizons probably reduced the observed eluvial enhancement enhancement of eluvial horizons and distribution throughout the soil oprofiles can be explained by common soil forming processes

travel times in the vadose zone variability in space and time water travel times reflect hydrological processes yet we know little about how travel times in the unsaturated zone vary with time using the soil physical model hydrus 1d we derived time variable travel time distributions for 35 study sites within the attert catchment in luxembourg while all sites experience similar climatic forcing they differ with regard to soil types 16 cambisols 12 arenosols and 7 stagnosols and the vegetation cover 29 forest and 6 grassland we estimated site specific water flow and transport parameters by fitting the model simulations to observed soil moisture time series and depth profiles of pore water stable isotopes with the calibrated model we tracked the water parcels introduced with each rainfall event over a period of several years our results show that the median travel time of water from the soil surface to depths down to 200 cm is mainly driven by the subsequent rainfall amounts the median time until precipitation is taken up by roots is governed by the seasonality of evapotranspiration rates the ratio between the amount of water that leaves the soil profile by on the one hand and evaporation and transpiration on the other hand also shows an annual cycle this time variable response due to climatic forcing is furthermore visible in the multimodal nature of the site specific master transit time distribution representing the flow averaged probability density for rainwater to become recharge the spatial variability of travel times is mainly driven by soil texture and structure with significant longer travel times for the clayey stagnosols than for the loamy to sandy cambisols and arenosols

digital terrain modelling a review of hydrological geomorphological and biological applications the topography of a catchment has a major impact on the hydrological geomorphological and biological processes active in the landscape the spatial distribution of topographic attributes can often be used as an indirect measure of the spatial variability of these processes and allows them to be mapped using relatively simple techniques many geographic information systems are being developed that store topographic information as the primary data for analysing water resource and biological problems furthermore topography can be used to develop more physically realistic structures for hydrologic and water quality models that directly account for the impact of topography on the hydrology digital elevation models are the primary data used in the analysis of catchment topography we describe elevation data sources digital elevation model structures and the analysis of digital elevation data for hydrological geomorphological and biological applications some hydrologic models that make use of digital representations of topography are also considered

assessing vertical soil moisture dynamics using multi frequency gpr common midpoint soundings summary soil moisture measurement techniques are of utmost importance to vadose zone hydrologists surface hydrogeophysical methods such as ground penetrating radar gpr have the capacity to provide field scale soil moisture information across a range of depth scales this paper presents an extensive field study using multi frequency i e 225 mhz 450 mhz 900 mhz gpr common midpoint cmp soundings to monitor a complete annual cycle of soil moisture conditions at three distinct sites we examine the use of normal moveout nmo velocity analysis applied to cmp data for monitoring highly dynamic vertical soil moisture conditions in a mid latitude climate consisting of wetting drying and freeze thaw cycles with varying degrees of magnitude and vertical velocity gradient nmo velocity analysis is used to construct interval velocity depth models at a fixed location collected every 1 4 weeks these time lapse models are combined to construct temporal interval velocity fields which are converted into soil moisture content using an appropriate petrophysical relationship using these moisture fields we were able to characterize the vertical distribution and dynamics of soil moisture in the shallow vadose zone although the use of multiple antenna frequencies provided varying investigation depths and vertical resolving capabilities optimal characterization of soil moisture conditions was obtained with high frequency 900 mhz antennas the integration of direct ground wave and nmo velocity data from a single cmp sounding allowed us to better refine the shallow soil moisture profile and underlying vadose zone conditions during seasonal wetting drying and freezing cycles this study demonstrates the capacity of gpr to characterize vertical moisture dynamics and highlights the importance of collecting high resolution data along the air soil interface to resolve the water content profile from the surface down to the deeper vadose zone conditions

book review biogeochemistry of amino acids edited by p e hare t c hoering and k king jr wiley 1980 538 pp 30 50

determining the impact of the holocene highstand at the coastal fluvial interface shoalhaven river south eastern australia with enhanced rates of sea level rise predicted for the next century the upstream extent of sea level influence across coastal plains is a topic of public importance australian coastal rivers provide a testing ground for exploring this issue because the area is tectonically stable was not glaciated and experienced a holocene highstand between 7 4 and 2 ka of up to 1 5 m above australian height datum ahd in the shoalhaven river of new south wales investigation of a confined bedrock reach at wogamia 32 km inland has identified a unit of dark cohesive silt and sand with marine diatoms shell fragments and enhanced pyrite content interpreted as estuarine the unit is up to 13 m thick thickens downstream and is overlain by fluvial channel and floodplain deposits the estuarine unit on laps a remnant pleistocene terrace and extends to approximately 2 2 m ahd optically stimulated luminescence osl and radiocarbon ages suggest that estuarine deposition commenced prior to 7 8 ka cal bp predating the highstand by 500 years and that marine influence in the area continued to 5 3 0 7 ka during this period a delta probably persisted at wogamia where a narrow upstream reach opens out and subsequently advanced to fill the broad shoalhaven coastal embayment although the effect of sea level rise depends on many factors the results suggest that during a highstand at or above present sea level a strong marine influence may extend for tens of kilometres inland and penetrate confined bedrock reaches landward of coastal embayments copyright 2013 john wiley sons ltd

relative sea levels and coastal sedimentation in southeast australia in the holocene abstract in recent years australian studies of relative sea level change have shown reasonable consistency on the termination date of the postglacial marine transgression at c 6 500 14c years bp the following stillstand period has been characterized in some regions by a slight falling trend from a high stand or in other areas by a level not easily distinguished from the present the latter situation occurs on the embayed coast of new south wales here studies of depositional environments and sequences within bed rock embayments have linked the holocene sea level history to patterns of sedimentation on the inner shelf in bay barriers and in estuaries deposition of quartz rich sand in shoreface flood tidal delta and backbarrier environments occurred during the marine transgre sion and the subsequent stillstand shell fragments from these deposits have been radiocarbon dated shoreline displacement continues to the present day partly in response to changes in availability of sand in the shoreface zone and partly in response to variations in regional storminess patterns a nd the great shroud of the sea rolled on as it rolled five thousand years ago herman melville moby dick

characterisation of soils by mineral magnetic measurements processes of iron mineral authigenesis diagenesis and dissolution in interaction with primary inputs of iron minerals act to produce vertical differentiation of soil magnetic properties thus magnetic iron oxides in common with other iron forms may both respond to and reflect soil forming processes investigation of the degree of detectable and persistent magnetic differentiation within different soil materials can provide insights into the nature and direction of distinct sets of soil processes evidence of clear association between magnetic variation and discrete types of soil environment also has applied significance in several areas of environmental study for example the observed magnetic variation can be used to discriminate between individual soils and soil horizons for the purposes of soil surveying sediment tagging and tracing and empirical modelling of source sediment linkages this paper reports the use of mineral magnetic techniques to characterise the iron oxide assemblages within soils of varying type and provenance the effect of different pedogenic regimes have been investigated through measurement of a range of magnetic parameters including magnetic susceptibility frequency dependent susceptibility and anhysteretic and saturation remanences contrary to current pedological thought but in accord with other magnetically based studies e g mullins the presence of magnetite maghemite typically of superparamagnetic single domain grain size within soils has been found to be an extremely widespread phenomenon its contemporary neoformation within the soil environment is inferred however the input of artificially generated ferrimagnetic material is indicated for one of the magnetically enhanced soils examined here and the possibility of extraneous sources of magnetite in topsoils should be considered before pedogenic processes of magnetic enhancement are inferred from the data presented discrimination of industrially derived magnetic particles appears possible on the basis of their very low levels of frequency dependent susceptibility fd low anhysteretic remanence arm and dissociation from the finer clay sized not the formation but the active dissolution of ferrimagnetic minerals is indicated for soils affected by the processes of gleying and podsolisation eluvial horizons of podsolised profiles demonstrate almost total loss of detectable magnetic content variations in the form of the iron reprecipitated in the underlying illuvial layers may reflect differences in the pedological characteristics of these horizons within gleyed waterlogged soils processes of magnetite dissolution appear to be grain size specific preferential reduction of those grains of ultrafine superparamagnetic and fine single domain magnetic grain size is indicated where soil forms a major contributor to catchment sediment loads this has significance in the area of source sediment modelling soil derived from permanently wet or highly leached catchment areas is unlikely to contribute to peaks in the magnetic content of deposited sediments further only those erosional processes that operate at a faster rate than those of magnetic depletion will have the capacity to produce peaks in sediment ferrimagnetic concentrations such as have been observed within the historical magnetic record

palynological foraminiferal and aminostratigraphic studies of quaternary sediments from the u s middle atlantic upper continental slope continental shelf and coastal plain abstract a pollen climate index curve provides the basic stratigraphic subdivision of the 305 m cored quaternary section of amcor 6021c located on the upper continental slope off new jersey u s a cold and warm intervals from top to bottom were assigned to marine oxygen isotope stages 1 through 13 at a sub bottom depth of about 220 m foraminiferal data indicate a possible hiatus and if so sediments below this may be as old as isotope stage 16 or older aminostratigraphic studies yielded results that are consistent with either interpretation benthic foraminifers are dominated by elphidium excavatum and islandiella norcrossi the planktic foraminiferal record provided no independent means of subdividing the section the stratigraphic distribution in 6021c of six species of quercus oak and aminozone determinations were applied to dating in terms of presumed oxygen isotope stages of other offshore core hole samples and some onshore quaternary deposits of delaware stratigraphic information from amcor sites 6021 and 6009 correlated to seismic reflection profiles that cross the shelf slope break indicate that the thickest accumulations of terrigenous quaternary sediments are located along the outer continental shelf upper continental slope offshore the northeastern united states

further amino acid racemisation evidence for glacial age multiple lowstand deposition on the new south wales outer continental shelf southeastern australia abstract amino acid racemisation aar analyses total acid hydrolysate on the fossil bivalve molluscs pecten fumatus and glycymeris radians from 10 vibracores from the new south wales continental shelf in present water depths ranging between 123 and 152 m below present sea level and extending some 300 km of latitude provide further evidence for multiple lowstand deposition at times of glacial maxima the extent of racemisation as determined for the amino acids alanine ala aspartic acid asp leucine leu and valine val indicate that the fossil molluscs plot into three principal aminogroups of contrasting age and in general accord with results previously obtained from three vibracores for the molluscs p fumatus and placamen placidium comparable extents of racemisation are evident in the fossil molluscs from the different cores providing a framework for a shelf wide regional aminostratigraphy fossil molluscs of the past three glacial maxima marine oxygen isotope stages ois 2 6 and 8 are identified within the vibracores based on amino acid racemisation evidence calibrated by radiocarbon dating of the same shell associations and correlation with independently dated deposits in southeastern australia the results extend the known geographical range of glacial age lowstand deposits on the mid and outer continental shelf of new south wales southeastern australia and help constrain the magnitude of sea level fall for the past three glaciations to at least 120 m below present sea level the extent of racemisation in specimens of p fumatus of marine ois 6 age with strongly indurated sediment encrustations adhering to the shell surfaces is significantly higher than for shells of equivalent age but without adhering sediment the higher extent of racemisation is consistent with a higher diagenetic temperature history for these specimens by implication these individual shells are likely to have remained within a relatively shallow water environment during the last glacial maximum resulting in the high degree of sediment induration and the higher extent of racemisation

late quaternary alluviation and soil formation in the southern argolid its history causes and archaeological implications in the context of an archaeological survey of the southern argolid greece studies have been carried out to elucidate the evolution of the landscape since its earliest known human occupation about 50 000 years ago one of these studies was a detailed geological mapping of the late quaternary alluvium and soils in the area dated by means of thorium uranium disequilibria archaeological finds and historical information seven periods of alluviation were identified each of short duration relative to long intervening periods of stability and soil formation the three earliest alluvial phases falling before and during the last glacial interval range from about 330 000 to 32 000 years in age no alluviation accompanied the last glacial maximum around 20 000 years ago in fact a stable landscape persisted until about 4500 years ago when debris flows and widespread aggradation in the valleys resulted from major slope destabilization and soil erosion probably as a result of extensive land clearance in the early bronze age a subsequent stable period lasted through the many upheavals of the later bronze age the dark ages and the early historical period it came to an end with a brief phase of alluviation between about 300 and 50 bc stability returned through the late roman period notwithstanding considerable expansion of the settled area another period of destabilization this one marked by debris flows and hence major soil erosion is poorly fixed in time but probably coincides with expanded maquis clearance accompanying the resettlement of the area around ad 1000 subsequent events of soil erosion and aggradation vary in nature and timing from one drainage to the next and in some areas continue today nature and chronology of the soil forming and alluviation events show that simple correlations with climatic events do not suffice to explain them for the latter ones past about 2500 bc human activity seems to be the dominant cause but once again the relation between cause and effect is not straightforward land clearing or neglect of soil conservation efforts during economic downturns appear to have a more devastating effect upon the landscape than do intensive land use or total land abandonment

review and comparison of models for describing non equilibrium and preferential flow and transport in the vadose zone abstract in this paper we review various approaches for modeling preferential and non equilibrium flow and transport in the vadose zone existing approaches differ in terms of their underlying assumptions and complexity they range from relatively simplistic models to more complex physically based dual porosity dual permeability and multi region type models a relatively simple dual porosity flow model results when the richards equation is combined with composite double hump type equations for the hydraulic properties to account for both soil textural matrix and soil structural fractures macropores peds effects on flow the simplest non equilibrium flow model a single porosity model which distinguishes between actual and equilibrium water contents is based on a formulation by ross and smettem soil sci soc am j 64 2000 1926 that requires only one additional parameter to account for non equilibrium a more complex dual porosity mobile immobile water flow model results when the richards or kinematic wave equations are used for flow in the fractures and immobile water is assumed to exist in the matrix we also discuss various dual permeability models including the formulation of gerke and van genuchten water resour res 29 1993a 305 and the kinematic wave approach as used in the macro model of jarvis technical description and sample simulations department of soil science swedish university of agricultural science uppsala sweden 1994 51 both of these models invoke terms accounting for the exchange of water and solutes between the matrix and the fractures advantages and disadvantages of the different models are discussed and the need for inter code comparison is stressed especially against field data that are sufficiently comprehensive to allow calibration validation of the more complex models and to distinguish between alternative modeling concepts several examples and comparisons of equilibrium and various non equilibrium flow and transport models are also provided

pleistocene coastal stratigraphy sea level highstands and neotectonism of the southern australian passive continental margin a review located in a tectonically stable intraplate setting and in the far field of former ice sheets the southern australian passive continental margin represents a globally important region for quantifying sea level during pleistocene highstands the stratigraphical record of the southern australian margin is dominated by geographically extensive coastal barrier estuarine and peritidal landforms of bioclastic temperate carbonate affinity a function of regional aridity siliciclastic successions dominate the eastern australian coastline despite the generally high level of tectonic stability regional contrasts are evident in the elevation of pleistocene shoreline deposits that largely relate to pre quaternary geotectonic setting the most complete record of pleistocene highstand deposits occurs in the murray basin coorong coastal plain region and indicates that interglacial sea level highstands for at least the past 11 interglacials did not deviate by more than 6 m from present sea level the pleistocene marginal marine record of southern australia is dominantly represented by coastal successions deposited during marine oxygen isotope stages 5e and 7 equating with relative sea level maxima of 2 6 m and greater than 1 m above present sea level apsl respectively intertidal facies of late pleistocene interstadial successions rarely occur above present sea level the most reliable record of glacio eustatic ice equivalent sea level is registered on coastlines developed on stable precambrian cratons such as the gawler craton eyre peninsula where a consistent elevation of 2 m apsl is registered for over 500 km for the last interglacial shoreline 125 ka copyright 2002 john wiley sons ltd

shore line reconstruction around australia during the last glacial maximum and late glacial stage abstract being both relatively tectonically stable and far from formerly glaciated regions continental australia is particularly well suited for the study of sea level evolution since the last glacial maximum lgm and the late glacial stage sea level data from such regions are valuable indicators of ice volume equivalent sea level since the effects of glacio hydro isostatic terms is less significant for far field sites though still not negligible in this study we review published sea level observations and results of recently developed numerical models for several areas of coastal australia and produce corresponding palaeogeographic maps of the results of our numerical models the results suggest that the australian continental shelf was largely exposed during the lgm and provide detailed predictions of the timing of inundation as a function of position temporal and spatial variation of sea level provide important constraints that can in turn be used to improve the accuracy of numerical models and better determine important rheological response parameters for the mantle and environmental conditions during the late glacial the palaeoshoreline data from the modeling performed in this study indicate several key locations for future palaeo environmental studies of sea level change

quantitative mapping of alluvial fan evolution using ground based reflectance spectroscopy abstract the ability of field based reflectance spectroscopy to resolve the relative proportions of fe oxides and clays in soils was used to map the composition relative age and distribution of segments within late quaternary fan systems in sfakia southwest crete the spectrometric results demonstrate that luvisols that have formed on the surfaces of fan segments are characterized by distinctive fe oxides types and clay minerals species furthermore fe oxide and clay concentrations display a clear and consistent trend whereby for each study fan luvisols formed on increasingly proximal fan segments are characterized by a progressive build up of spectrally distinct secondary iron oxides and clay minerals which suggests that proximal segments formed first the relative ages and hence order of formation of segments suggested by the spectral data are strongly supported by an optically stimulated luminescence osl based geochronology which provides a tentative maximum age of 144 ka for the oldest stage 1 surface and 11 2 ka for the youngest stage 2c surface moreover the chronometric data indicate that time intervals of the order 20 to 25 000 years are necessary to generate sufficient differences in pedogenic fe oxides and clay concentrations to enable differentiation of fan segments by field spectroscopy

a new triangular multiple flow direction algorithm for computing upslope areas from gridded digital elevation models 1 gridded digital elevation data often referred to as dems are one of the most widely available forms of environmental data topographic analysis of dems can take many forms but in hydrologic and geomorphologic applications it is typically used as a surrogate for the spatial variation of hydrological conditions topographic indices and flow routing here we report on a new flow routing algorithm and compare it to three common classes of algorithms currently in widespread use the advantage of the new algorithm is that unrealistic dispersion on planar or concave hillslopes is avoided whereas multiple flow directions are allowed on convex hillslopes we suggest that this new triangular multiple flow direction algorithm md1 is more appropriate for a range of flow routing and topographic index applications

ecohydrological separation in wet low energy northern environments a preliminary assessment using different soil water extraction techniques ecohydrological studies in seasonally dry climatic regions have revealed isotopic separation of the sources of water used by trees and those that generate stream flow also referred to as the two water worlds hypothesis here we investigated whether similar separation occurs in a wet low energy northern latitude 57 environment in scotland for two common soil types histosols and podzols at three soil depths and at both forested with scots pine pinus sylvestris and non forested sites we compared the stable isotope composition of soil water held at increasing soil water tensions these were assessed by different soil water extraction techniques rhizon samplers mobile water centrifugation at different speeds representing different tensions and cryogenic extraction bulk water sampling occurred during a relatively dry summer water that was held at increasing tensions appeared more depleted than more mobile water consistent with older winter precipitation this pattern was independent of soil type vegetation cover and time during the growing season although there was a slight tendency towards less separation with soil depth nevertheless soil waters in this generally wet low energy environment exhibited only minor evaporative enrichment limited to the upper soil profile only furthermore stream water showed no deviation from the local meteoric water line preliminary sampling for tree xylem water suggested uptake of evaporated soil water from the near surface soil horizons upper 10 cm where fine root densities are concentrated for histosols in particular tree water appeared lagged in its isotopic composition compared to the soil water time series although more work is needed to fully test the two water worlds hypothesis our initial analyses did not provide clear evidence to support this in wet low energy northern environments copyright 2015 john wiley sons ltd

spatial and temporal dynamics of water flow and solute transport in a heterogeneous glacial till the application of high resolution profiles of δ18o and δ2h in pore waters summary the heterogeneity and dynamic of water flow and solute transport processes were investigated in the upper 6 m of a surficial glacial till in southern saskatchewan canada continuous core samples from three vertical sites located over a maximum spatial distance of 65 m were collected and analyzed for particle size distribution porosity and water content high resolution 0 2 m profiles of 18o and 2h in pore waters were also measured for the three sites on a seasonal basis depth profiles of all measured parameters indicate highly heterogeneous structures in the upper 6 m in two coreholes depleted water isotopes measured at different depths below ground 0 7 and 3 m were in the range of winter precipitation values suggesting preferential flow of meltwater in spring accompanied by a rising water table a one dimensional equilibrium flow and transport model failed to simulate the isotope depth distributions with depleted winter values and could not reproduce the measured values even when accounting for vertical preferential flow a conceptual model was created based on the consistency of all measured data and assuming preferential lateral flow as the controlling flow and transport mechanism after snowmelt in the model water from surface runoff after snowmelt drains into an ephemeral depression that crosses the study site as this water infiltrates it forms a water table mound that slowly propagates away from the depression as the water table propagates outwards dynamic vertical flow processes result in net upward and downward fluxes

process identification at a slow moving landslide in the vorarlberg alps a fine grained slope that exhibits slow movement rates was investigated to understand how geohydrological processes contribute to a consecutive development of mass movements in the vorarlberg alps austria for that purpose intensive hydrometeorological hydrogeological and geotechnical observations as well as surveying of surface movement rates were conducted during 1998 2001 subsurface water dynamics at the creeping slope turned out to be dominated by a three dimensional pressure system the pressure reaction is triggered by fast infiltration of surface water and subsequent lateral water flow in the south western part of the hillslope the related pressure signal was shown to propagate further downhill causing fast reactions of the piezometric head at 5 5 m depth on a daily time scale the observed pressure reactions might belong to a temporary hillslope water body that extends further downhill the related buoyancy forces could be one of the driving forces for the mass movement a physically based hydrological model was adopted to model simultaneously surface and subsurface water dynamics including evapotranspiration and runoff production it was possible to reproduce surface runoff and observed pressure reactions in principle however as soil hydraulic functions were only estimated on pedotransfer functions a quantitative comparison between observed and simulated subsurface dynamics is not feasible nevertheless the results suggest that it is possible to reconstruct important spatial structures based on sparse observations in the field which allow reasonable simulations with a physically based hydrological model copyright 2004 john wiley sons ltd

post glacial sea level changes around the australian margin a review abstract it has been known since rhodes fairbridge s first attempt to establish a global pattern of holocene sea level change by combining evidence from western australia and from sites in the northern hemisphere that the details of sea level history since the last glacial maximum vary considerably across the globe the australian region is relatively stable tectonically and is situated in the far field of former ice sheets it therefore preserves important records of post glacial sea levels that are less complicated by neotectonics or glacio isostatic adjustments accordingly the relative sea level record of this region is dominantly one of glacio eustatic ice equivalent sea level changes the broader australasian region has provided critical information on the nature of post glacial sea level including the termination of the last glacial maximum when sea level was approximately 125 m lower than present around 21 000 19 000 years bp and insights into meltwater pulse 1a between 14 600 and 14 300 cal yr bp although most parts of the australian continent reveals a high degree of tectonic stability research conducted since the 1970s has shown that the timing and elevation of a holocene highstand varies systematically around its margin this is attributed primarily to variations in the timing of the response of the ocean basins and shallow continental shelves to the increased ocean volumes following ice melt including a process known as ocean siphoning i e glacio hydro isostatic adjustment processes several seminal studies in the early 1980s produced important data sets from the australasian region that have provided a solid foundation for more recent palaeo sea level research this review revisits these key studies emphasising their continuing influence on quaternary research and incorporates relatively recent investigations to interpret the nature of post glacial sea level change around australia these include a synthesis of research from the northern territory queensland new south wales south australia and western australia a focus of these more recent studies has been the re examination of 1 the accuracy and reliability of different proxy sea level indicators 2 the rate and nature of post glacial sea level rise 3 the evidence for timing elevation and duration of mid holocene highstands and 4 the notion of mid to late holocene sea level oscillations and their basis based on this synthesis of previous research it is clear that estimates of past sea surface elevation are a function of eustatic factors as well as morphodynamics of individual sites the wide variety of proxy sea level indicators used their wide geographical range and their indicative meaning some progress has been made in understanding the variability of the accuracy of proxy indicators in relation to their contemporary sea level the inter comparison of the variety of dating techniques used and the nuances of calibration of radiocarbon ages to sidereal years these issues need to be thoroughly understood before proxy sea level indicators can be incorporated into credible reconstructions of relative sea level change at individual locations many of the issues which challenged sea level researchers in the latter part of the twentieth century remain contentious today divergent opinions remain about 1 exactly when sea level attained present levels following the most recent post glacial marine transgression pmt 2 the elevation that sea level reached during the holocene sea level highstand 3 whether sea level fell smoothly from a metre or more above its present level following the pmt 4 whether sea level remained at these highstand levels for a considerable period before falling to its present position or 5 whether it underwent a series of moderate oscillations during the holocene highstand

calibration of the c 14 timescale over the past 30 000 years using mass spectrometric u th ages from barbados corals uranium thorium ages obtained by mass spectrometry from corals raised off the island of barbados confirm the high precision of this technique over at least the past 30 000 years comparison of the u th ages with 14c ages obtained on the holocene samples shows that the u th ages are accurate because they accord with the dendrochronological calibration before 9 000 yr bp the 14c ages are systematically younger than the u th ages with a maximum difference of 3 500 yr at 20 000 yrbp the u th technique thus provides a way of calibrating the radiocarbon timescale beyond the range of dendrochronological calibration

theoretical correlations and lateral discontinuities in the quaternary aminostratigraphic record of the u s atlantic coastal plain abstract aminostratigraphic correlations of emergent quaternary deposits along the u s atlantic coastal plain have employed independent radiometric data regional temperature history models and assumptions regarding the nature of the preserved late quaternary sea level record on this passive margin a substantial aminostratigraphic offset is required if regional aminozones are rigorously constrained by all available th u data new insights regarding the relation of this offset to subsurface stratigraphy in the cape fear region of southeastern north carolina can explain these conflicts as consequences of the highly incomplete post cretaceous depositional record of the region southward projection of theoretical aminostratigraphic correlation trends suggests that stage 5 correlative marine units are rarely preserved on the emergent portion of the coastal plain between cape lookout and central south carolina and that samples of this age would be most frequently found in this region only as fragmentary and or reworked deposits on the inner shelf or in the subsurface of modern barrier islands if this hypothesis is correct then the accuracy of several th u coral dates from the south carolina coastal plain must be questioned along with sea level tectonic and paleoclimatic conclusions derived from these dates

amino acid geochronology resolution and precision in carbonate fossils changes in indigenous proteins preserved in carbonate skeletons can be used to estimate the time elapsed since death of the organism racemization the most widely used reaction in amino acid geochronology refers to the inversion of l amino acids to their d configuration for the protein amino acid l isoleucine racemization occurs about only one of the two chiral carbon atoms this reaction epimerization proceeds from an initial dl ratio near zero to an equilibrium ratio of about 1 30 the reaction rate is controlled primarily by temperature and to a lesser degree by the nature of the proteins themselves a variable related to taxonomy and the extent of protein degradation analyzing monospecific samples minimizes the taxonomic variable the resolving power of dl ratios as relative age indices is a function of the reaction rate degree of natural variability and analytical uncertainty natural variability is defined as the spread in ratios in five well preserved shells of the same age from a single stratum and is primarily related to taxonomy it can range from 20 or more in taxa of low reliability to 1 in taxa of greatest integrity 5 to 10 is to be expected analytical uncertainty within a single laboratory is relatively insignificant amounting to no more than 2 but interlaboratory comparisons suggest caution in comparing ratios determined at different laboratories or by different techniques sampling appropriate portions of a shell is essential to minimize variability in dl ratios site temperature exerts the greatest control on reaction rate hence resolving power for tropical sites 25 c age differences 1 ka can be resolved within the holocene and ca 5 to 10 ka for older samples as the rate decreases equilibrium is attained after 150 to 300 ka the reaction rate is substantially lower at mid latitude sites ca 10 c where equilibrium requires about 2 ma and resolution within the last glacial cycle is no better than 10 to 20 ka arctic sites 10 c show almost no measurable racemization within the holocene and in extreme cases even within the last 100 ka equilibrium is not attained in 10 ma the extent of amino acid racemization epimerization in carbonate fossils provides chronological information for the critical time period beyond radiocarbon dating dl ratios can be used directly as relative age indices and with suitable calibration can provide reasonable estimates of absolute age and or effective diagenetic temperature improving the accuracy of racemization based age estimates requires a better understanding of racemization kinetics in carbonate systems

coastal aminostratigraphy of the last interglaciation in southern australia abstract amino acid racemization data for marine molluscs of the last interglaciation from southern australia provide the basis for a predictive model for relative dating of late quaternary sequences genera analyzed include anadara sp katelysia sp glycymeris sp and fulvia sp that exhibit moderate racemization rates a genus effect on racemization is not evident in these taxa coefficients of variation for intershell d l ratio variation for each deposit are generally less than 12 the extent of racemization in molluscan fossils of the last interglaciation from temperate coastal settings in southern australia represents an exponential function of temperature and is in general accord with data from northern hemisphere sites with similar contemporary mean annual temperature values these data highlight the potential of amino acid racemization for global correlation programs the amino acid data from southern australia suggest however that a larger margin of variation may have to be accounted for in stratigraphic correlation as indicated by the greater scatter of data around the oxygen isotope substage 5e isochron these data have implications regarding the age resolving power of amino acid racemization

chronological studies of the quaternary marine sediments of northern spencer gulf south australia abstract four dating methods have been used to obtain chronological information about holocene and pleistocene coastal marine sediments in south australia and to check the stratigraphic reliability of each dating technique estimates of accumulation rates for holocene seagrass bank deposits vary according to the time period over which they are averaged the estimates vary from 2 0 to 2 7 mm yr 1 for measurements by the pb 210 method averaged over about 100 years to 1 4 0 2 mm yr 1 for c 14 derived measurements averaged over a period of 1000 7000 yrs radiocarbon age determinations on carbonate and organic fractions do not date the true sediment age shells shell fragments and calcareous fines predate the sediment whereas organic and seagrass detritus postdate it by dating sample pairs their age can be adequately defined thermoluminescence age estimates correlate well with available c 14 ages where the sediment grains have experienced good exposure to sunlight prior to deposition amino acid racemization and thermoluminescence measurements indicate a late pleistocene age of ca 110 000 yrs for the mambray formation of spencer gulf amino acid racemization data also support a correlation with the late pleistocene glanville formation of adelaide

the application of mineral magnetic and extractable iron fed analysis for differentiating and relatively dating fan surfaces in central greece mineral magnetic and extractable iron analyses of bt horizons of fan surface soils were undertaken in order to differentiate and rank by order of formation discrete fan surfaces within a debris flow fluvial fan in the tithorea basin central greece detailed topographic surveying initially suggested a simple fan surface morphology which consists of a steep proximal surface and a gently sloping but extensive distal surface in contrast mineral magnetic and extractable iron data suggest a more complex fan surface morphology which comprises a steep proximal surface less steep upper and lower medial surfaces and a gently sloping distal surface the mineral magnetic and extractable iron data indicate that soils of the upper fan surface contain the highest concentration of ferrimagnetic and anti ferromagnetic minerals while soils developed on successively lower surfaces are characterised by a progressively lower concentration of both types of magnetic mineral the trend in magnetic mineral concentration suggests that the upper surface formed first followed by the upper and lower medial surfaces and finally the distal surface therefore fan surfaces become progressively younger the greater the distance from the fan apex translating this trend in terms of the likely pattern of fan development during the late pleistocene deposition initially occurred at the range front to form the upper fan surface subsequent depositional events throughout the holocene coincided with incision of the fan head and a progressive shift of the locus of deposition towards the interior of the tithorea basin forming the medial and distal fan surfaces in the process

unravelling patterns of reworking in lowstand shelf deposits using amino acid racemisation and radiocarbon dating abstract amino acid racemisation calibrated by radiocarbon dating liquid scintillation and accelerator mass spectrometry has provided a chronostratigraphic framework in which to evaluate the later quaternary evolution of mollusc rich carbonate sediments on the outer continental shelf of new south wales australia three vibracores cores 112 vc 130 112 vc 121 and 112 vc 134 from the outer continental shelf in present water depths of 123 139 and 150 m respectively each contain alternating successions of pedogenically unmodified fine grained mixed quartz carbonate sand and densely packed mollusc dominated sediments set in a matrix of carbonate sand the extent of racemisation for several amino acids and radiocarbon dates on the shallow water molluscs pecten fumatus and placamen placidium reveals the presence of sediments deposited during three successive glacial maxima i e stages 8 6 and 2 of the marine oxygen isotope record three chronostratigraphically distinct aminozones oxygen isotope stages 8 6 and 2 are identified in core 134 samples in cores 121 and 130 record only two aminozones collectively stages 6 and 2 amino acid racemisation indicates that fossil molluscs with background radiocarbon results are in fact significantly beyond the range of radiocarbon dating by analogy with other deposits from southern australia a thin veneer of early holocene fine calcareous sand occurs at the top of each core all three cores reveal varying degrees of reworking of fossil molluscs which is not immediately apparent on the basis of lithostratigraphy or biostratigraphy reworking of macrofossils is more pronounced closer to the inferred location of the palaeoshoreline of pleistocene glacial maxima

australia an unstable platform for tide gauge measurements of changing sea levels a discussion the recent detailed analyses by aubrey and emery 1986 of australian sea level trends continues their efforts to define tectonic and climatic factors worldwide that dominate longand short term fluctuations respectively in sea level records these factors have included sediment and water loading on the adjacent shelf the tectonic behaviour of plates fluctuations in the southern oscillation behaviour of currents impinging on the shelf and river runoff we do not object to these efforts however we are disturbed by misrepresentations in their recent paper on australian sea levels regarding 1 the interpretation of the nature of sea level records 2 the use of tectonic explanations to account for low frequency sea level trends and 3 the somewhat incomplete and sometimes inaccurate consideration of the effects of climatic variables upon sea level fluctuations and trends

new research on the development of high resolution palaeoenvironmental proxies from geochemical properties of biogenic carbonates abstract geochemical signatures from biogenic carbonates are being increasingly employed as palaeoenvironmental proxies in turn many of these proxy archives including mollusc shells corals and otoliths have periodic growth structures which allow the reconstruction of chronologically constrained records of palaeoenvironmental variability at unparalleled high temporal resolution studying the growth and chemistry of these periodic growth structures is known as sclerochronology biogenic hard parts accumulate in geological or archaeological deposits and can be directly dated using radiometric and racemisation methods they therefore offer the opportunity for high resolution palaeoenvironmental reconstructions across many time intervals all over the globe such data are important for several reasons 1 understanding past climate and environmental change provides a means of contextualising current and future climate change and ecological disturbance 2 high resolution palaeoenvironmental records are essential for constraining testing and validating global and regional numerical climate models 3 palaeoenvironmental records from biogenic carbonates can provide an environmental framework from which to understand the behavioural changes and interactions of peoples with their environment however inter and intra species differences in growth rate physiology and environmental response can cause variations in the chemical profiles of biogenic carbonates before geochemical data is employed for palaeoenvironmental reconstructions it is thus necessary to examine modern specimens of the target species or related taxa to understand how geochemical variations are influenced by local environmental conditions kinetic and vital effects this allows the generation of quantitative and more reliable proxy records of environmental change this special issue brings together the latest research on palaeoenvironmental proxy development and validation in biogenic carbonates it includes studies on marine freshwater and estuarine organisms molluscs corals and echinoderms and on traditional as well as novel geochemical proxies the papers presented here include in situ field calibration studies laboratory growth experiments as well as methodological studies into the effects of sampling and pre treatment the geographical scope is broad encompassing both the northern and southern hemispheres including south africa south america australia asia the mediterranean sea and the north atlantic

towards a high resolution global deep sea chronology for the last 750 000 years abstract variations in the ratio of 18 o 16 o as measured in shells of marine calcareous microfossils are primarily dominated by changes in global ice volume hence these variations provide a set of global time lines in deep sea sediments it is likely that the timing of major changes in oxygen isotope values is strongly influenced if not controlled by variations in the geometry of the earth s orbit since the variation of orbital parameters can be accurately calculated the opportunity exists for transforming this orbital chronology into a geological chronology through careful correlation of oxygen isotope records in a set of deep sea cores from the sub antarctic south atlantic and equatorial pacific we have assembled a composite isotopic section spanning the last 750 000 years with an average sedimentation rate of 2 3 cm 1000 years a new chronology for this time period was developed by adjusting the ages of the oxygen isotope stage boundaries in this composite section so as to extend the consistent phase relationships that exist between variations in oxygen isotope ratios and changes in obliquity and precession during the last 300 000 years to the entire 750 000 year record previously identified difficulties in phase locking precession with the filtered isotopic signal between 365 000 and 465 000 years b p have been resolved with the recognition that precessional variations have an average period of 19 000 years and not 23 000 years during this interval since this new age model yields the best match between variations in obliquity and precession and their corresponding frequency components in the oxygen isotope record we believe that it presents the most accurate chronology yet developed for deep sea sediments with this new age model providing the time control power spectral analyses of south atlantic and sub antarctic chemical and biotic indices show that there is a strong tendency for variance to be concentrated at frequencies corresponding to periods of 100 000 41 000 and 23 000 years

reddening of dune sands evidence from southeast india thin section sem and tem analyses have indicated that the red teri sands of southeast india have formed from weathering in situ of coastal dune sands the data does not support a detrital origin for the red sands c14 dates indicate that dune deposition and weathering to a maximum depth of 10 m leading to the formation of a hematite koalinite and illite rich matrix has taken place rapidly over the past 25 000 years it is postulated that garnet was a major source of hematite ferric oxide

a late quaternary record of vegetation and climate change from hazards lagoon eastern tasmania a late quaternary pollen and charcoal record from hazards lagoon on the east coast of tasmania provides a continuous record of vegetation and climate change the pollen record shows an epacridaceae and poaceae dominated grassland community replaced dry sclerophyll forest during the last glacial maximum lgm 22 18 cal ka bp eucalyptus and casuarinaceae increased from the beginning of the deglacial period 18 12 cal ka bp indicating early warming on the east coast of tasmania abundant myriophyllum and sedimentary characteristics indicate hazards lagoon was a permanent source of water throughout the lgm and until 16 cal ka bp suggesting either increased precipitation and or decreased evaporation rates a positive moisture balance throughout the lgm contrasts with records from the west coast of tasmania and parts of mainland australia fire was suppressed at the site until 14 cal ka bp corresponding with reduced woody vegetation and a positive moisture balance dry sclerophyll forest established during the deglacial period remaining stable throughout the holocene a coastal vegetation community developed in response to sea level rise characterised by abundant eucalyptus pollen and increasing values of casuarinaceae by the mid holocene the hazards lagoon pollen record is typical of a tasmanian coastal site dominated by casuarinaceae this research highlights the need for spatially diverse studies throughout the southern hemisphere to identify drivers of environmental change during the late quaternary

conditions for lateral downslope unsaturated flow and effects of slope angle on soil moisture movement summary the necessary conditions for lateral downslope flow in the unsaturated zone in hillslopes have not been clearly identified and the effects of different slope angles on soil moisture movement are rarely studied these questions were investigated through drying processes in a homogeneous and isotropic sloping soil tank in this study three experiments with different slope angles were conducted the results showed that the flow direction in the unsaturated zone gradually rotates counterclockwise from the vertical direction to the lateral downslope direction parallel to the slope surface during the drying phase the lateral downslope flow parallel to the slope surface first appears at the surface 0 5 cm and the bottom of the sandy loam in the tank the lateral downslope flow parallel to the slope surface at the surface is due to the state of drying rather than the no flow upper boundary condition the lateral downslope flow parallel to the slope surface at the bottom of the sandy loam is also caused by the state of drying more importantly the results of this study showed that the rate at which the lateral downslope flow turns to be parallel to the slope surface is affected by the drainage rate in contrast to the lateral downslope flow component parallel to the slope surface the flow component normal to the slope surface is less sensitive to changes in the slope angle the influence of the slope angle on the flow component normal to the slope surface is greatest in the middle layer

optical dating and soil micromorphology at maccauley s beach new south wales australia the ability to position landscapes in a context of time and space is a particular goal of quaternary science research the lack of context for dating samples published previously for maccauley s beach an important site for the reconstruction of australian sea levels warranted a re evaluation of both the site stratigraphy and chronology in this study we combined optically stimulated luminescence osl dating of sedimentary quartz grains and soil micromorphology of the same samples to improve our understanding of the depositional history and chronology of the sediments this combination allowed the contextualization of samples not only in time and space but also in terms of their depositional histories the latter is important in osl dating where pre syn and post depositional processes can all influence the accuracy and precision of the final age estimates the sediment profile at maccauley s beach is made up of three major units the basal mottled mud layer has undergone extensive pedogenesis since deposition and only a minimum age of 14 7 2 7 ka could be calculated the overlying grey mud with osl ages from the bottom and top of the unit of 10 0 0 7 and 7 7 0 5 ka respectively shows evidence of soil structure collapse this unit correspond to the onset of the mid holocene sea level high stand for this region the overlying sand layer was first deposited at 7 5 0 4 ka with deposition continuing beyond 6 6 0 4 ka not only does the chronology presented constrain the timing of deposition and the extent of post depositional processes at maccauley s beach but the methodological approach used here can be applied to any site to aid in the interpretation of formation processes and assess their influence on osl age determination copyright 2014 john wiley sons ltd

transport of stable isotopes of water and sulphate within reclaimed oil sands saline sodic mine overburden summary the reclamation of shale overburden dumps from oil sands mining requires the placement of reclamation covers comprised of salvaged organic and mineral soils the primary issues associated with the long term performance of these covers are their ability to store sufficient water to meet transpiration demands and the potential threat of salt ingress into the cover from the underlying shale the first issue has been addressed in previous studies so the objective of this study was to evaluate controls on salt ingress through observations and modelling of the transport of the stable isotopes of water and salt within reclaimed profiles at the south bison hills overburden dump located north of fort mcmurray alberta the water flow model was based on a dual porosity soil vegetation atmosphere model calibrated to observed field data this model was then used to simulate deuterium and sulphate transport within the soil profiles the optimized transport model for deuterium was used to estimate net percolation rates through the cover soil into the underlying shale this model was then used to assess the controls on sulphate migration including the rate of sulphate generation as a result of ongoing oxidation of the pyritic shale the model results indicate that the average net percolation rate is a function of topographic location ranging from 2 2 10 5 m d at slope locations to 20 8 10 5 m d at plateau locations during the unfrozen days these rates of net percolation should have produced observable patterns of salt flushing from the cover and upper shale however the observed sulphate levels could only be simulated by including a production term related to pyrite oxidation of the shale the simulated oxidation rates ranged from 0 4 to 5 65 mg l d similar to those estimated from previous laboratory and field investigations

segmentation of alluvial fans in death valley california new insights from surface exposure dating and laboratory modelling laboratory experiments recent paleoenvironmental analyses of rock varnish and surface exposure dating of geomorphic units have led to new insights into the process of entrenchment and segmentation of alluvial fans and into the history of quaternary sedimentation in death valley entrenchment begins at the fanhead as the trench deepens its down slope end migrates down fan taking several tens of thousands of years to reach lower parts of the fan laboratory experiments suggest however that a new segment begins to grow at the toe long before the trench reaches this part of the fan furthermore the initial slope of the segment is not the equilibrium slope field evidence supports this model the tectonic tilting that caused entrenchment and segmentation in death valley may have been triggered by loading of the valley with water sedimentation on the salt pan in southern death valley is not at present in equilibrium with that on the fans rather it seems to be adjusting to an increase in the amount of fine material reaching the playa due in part to breaching of the outlet of lake tecopa somewhat after 600 ka bp and in part to subsidence of different parts of the valley at different rates failure to recognize this disequilibrium resulted in errors in earlier estimates of the age of the segmentation events

the coupling status of alluvial fans and debris cones a review and synthesis alluvial fans and debris cones link two zones of the fluvial system e g hillslope gully systems to stream channels mountain catchment sediment source areas to main river systems or to sedimentary basins and therefore have important coupling or buffering roles these roles may be both functional and preservational the functional role includes debris cone coupling which controls sediment supply from hillslope gully systems to stream channels influencing channel morphology coupling through larger alluvial fans expressed by fanhead trenching causes a distal shift in sedimentation zones or when expressed by through fan trenching causes complete sediment by pass the preservational role stems from the fact that fans and cones are temporary sediment storage zones and may preserve a record of source area environmental change more sensitively than would sediments preserved further downsystem fan coupling mechanisms include distally induced coupling basal scour toe cutting marginal incision and proximally induced coupling fanhead and midfan trenching these mechanisms lead initially to partial coupling either extending the immediate sediment source area to the stream system or shifting the focus of sedimentation distally complete coupling involves transmission of sediment from the feeder catchment through the fan environment into the downstream drainage or a sedimentary basin the implications of coupling relate to downstream channel response fan morphology sedimentation patterns and vertical sedimentary sequences temporal and spatial scales of coupling are related and with increasing scales the dominant controls shift from storm events to land cover to climatic and base level change and ultimately to the relationships between tectonics and accommodation space finally future research challenges are identified modern dating techniques and sophisticated analysis of remotely sensed data can greatly improve our understanding of fan dynamics and should lead to better cross scale integration between short term process based approaches and long term sedimentological applications while maintaining high quality field based observations copyright 2011 john wiley sons ltd

snowmelt infiltration to frozen prairie soils the paper summarizes the results of 5 years of study of the interaction between snowmelt infiltration inf snow cover water equivalent swe and soil moisture content at the time of melt p for soils in the brown and dark brown zones of the canadian prairies it is shown that in uncracked soils the depth infiltrating water percolates into the soil during the melt sequence is on the average approximately 30 cm and that p of the frozen layer at the soil surface 0 30 cm is the dominant factor governing the amount of snowmelt infiltration independent of soil texture and vegetative cover empirical expressions in the form of power equations and graphs are presented describing the relationship between the variables because of their simplicity they have direct practical application to a number of water management problems of the region a conceptual model for describing the snowmelt infiltration phenomenon in operational water management schemes is presented it divides the infiltration potential o

tracking water pathways in steep hillslopes by δ18o depth profiles of soil water assessing temporal variations in soil water flow is important especially at the hillslope scale to identify mechanisms of runoff and flood generation and pathways for nutrients and pollutants in soils while surface processes are well considered and parameterized the assessment of subsurface processes at the hillslope scale is still challenging since measurement of hydrological pathways is connected to high efforts in time money and personnel work the latter might not even be possible in alpine environments with harsh winter processes soil water stable isotope profiles may offer a time integrating fingerprint of subsurface water pathways in this study we investigated the suitability of soil water stable isotope d18o depth profiles to identify water flow paths along two transects of steep subalpine hillslopes in the swiss alps we applied a one dimensional advection dispersion model using d18o values of precipitation ranging from 24 7 to 2 9 as input data to simulate the d18o profiles of soil water the variability of d18o values with depth within each soil profile and a comparison of the simulated and measured d18o profiles were used to infer information about subsurface hydrological pathways the temporal pattern of d18o in precipitation was found in several profiles ranging from 14 5 to 4 0 this suggests that vertical percolation plays an important role even at slope angles of up to 46 lateral subsurface flow and or mixing of soil water at lower slope angles might occur in deeper soil layers and at sites near a small stream the difference between several observed and simulated d18o profiles revealed spatially highly variable infiltration patterns during the snowmelt periods the d18o value of snow 17 7 1 9 was absent in several measured d18o profiles but present in the respective simulated d18o profiles this indicated overland flow and or preferential flow through the soil profile during the melt period the applied methods proved to be a fast and promising tool to obtain time integrated information on soil water flow paths at the hillslope scale in steep subalpine slopes

recharge processes during snowmelt an isotopic and hydrometric investigation results from hydrometric and isotopic investigations of unsaturated flow during snowmelt are presented for a hillslope underlain by well sorted sands passage of melt and rainwater through the vadose zone was detected from temporal changes in soil water 2h concentrations obtained from sequential soil cores bypassing flow was indicated during the initial snowmelt phase but was confined to the near surface zone recharge below this zone was via translatory flow as meltwater inputs displaced premelt soil water estimates of premelt water fluxes indicate that up to 19 per cent of the premelt soil water may have been immobile average water particle velocities during snowmelt ranged from 6 2 10 7 to 1 1 10 6 ms 1 suggesting that direct groundwater recharge by meltwater during snowmelt was confined to areas where the premelt water table was within 1 m of the ground surface soil water 2h signatures showed a rapid response to isotopically heavy rain on snow inputs late in the melt in addition spatial variations in soil moisture content at a given depth induced a pronounced lateral component to the predominantly vertical transport of water both factors may complicate isotopic profiles in the vadose zone and should be considered when employing environmental isotopes to infer recharge processes during snowmelt

use of multiparameter relative age methods for age estimation and correlation of alluvial fan surfaces on a desert piedmont eastern mojave desert california numerical and calibrated age determinations of the late quaternary alluvial fan deposits of the soda mountains piedmont in the mojave desert provide an opportunity to study the utility of the multiparameter relative age ra method for distinguishing and mapping geomorphic surfaces on a desert piedmont most ra parameters could not discriminate between deposits of holocene age although pavements have formed over locally significant parts of surfaces as young as middle holocene several parameters including lithologic composition particle size soil development and varnish cover permit distinguishing between holocene surfaces and late pleistocene surfaces statistically significant differences in initial particle size and lithology of the deposits inferred to be the result of complex interaction among hillslope alluvial fan and eolian processes and climatic change create conditions unfavorable for use of most ra techniques in contrast soil profile development and varnish cover data are successful in discrimination among deposits of holocene and pleistocene age this is attributed to the development of pedogenic features and varnish that are strongly dependent on dust influx and to the relatively minor dependence of these features on differences in the depositional character of the fan

high resolution profiling of the stable isotopes of water in unsaturated coal waste rock summary characterization of the rate of water migration through unsaturated mine waste rock dumps is an essential element in assessing the chemical loading from these landforms yet our understanding of how water moves into through and out of waste rock is incomplete to further understand the rates and magnitude of percolation through waste rock deep high resolution every 0 1 4 5 m depth profiles of the stable isotopes of water 2h and 18o at two coal waste rock dumps and a natural alluvial deposit down gradient of one of the dumps were collected in the elk valley british columbia canada the profiles were generated using vapor equilibrium techniques applied to continuous core samples collected using dry sonic drilling methods elevated core temperatures up to 80 c were measured during sonic coring the isotopic values of pore waters measured in the core samples were corrected for water loss to the atmosphere attributed to the elevated core temperatures the average isotopic composition of the core samples were compared to water collected from rock drains discharging from the base of the dumps the results indicate that high resolution profiles of 2h and 18o can be measured to depths of 86 m in coal waste rock dumps and based on the seasonal cycles in the isotopic composition of recharging water can be used to characterize the migration of recharge water within these dumps these profiles also suggest that recharge into these dumps occurs from both rain as well as snow melt and may be as high as 400 600 mm yr 60 75 of annual precipitation combined with the relatively low volumetric water contents of these dumps 5 10 the rates of water migration through the dumps are tens of meters each year

a stable isotope study of recharge processes in the english chalk the 2h and 18o values of water contained in unsaturated chalk have been measured in drillcore profiles taken over a period of 28 months on arable land in cambridgeshire eastern england the isotopic composition of rainfall and lysimeter drainage on the same site has also been monitored over a period of four years the distribution of isotope values in the upper few metres of soil and unsaturated chalk shows that the mechanism of infiltration is not simple piston like downward displacement since the scale of vertical fluctuations is incompatible with estimated annual infiltration and the apparent rates of movement of matrix water derived from thermonuclear tritium studies lysimeter drainage is not isotopically identical to matrix water at the same depth suggesting that different routes to water table are associated with consistently different isotopic content although there is an apparent difference between matrix water beneath arable and permanent grassland these differences appear to cancel out in the composition of bulk recharge beneath these land types the regional aquifer has a uniform isotopic composition similar in value to weighted average rainfall and lysimeter drainage suggesting that the recharge abstraction system has been in isotopic equilibrium for many years despite changes in pumping rates and land use two other chalk sites in southern england have been investigated in less detail but indicate clear difference in infiltration behaviour from that seen in cambridgeshire this seems to be related to a higher matrix conductivity and annual rainfall amount

links between climate and sea levels for the past three million years the oscillations between glacial and interglacial climate conditions over the past three million years have been characterized by a transfer of immense amounts of water between two of its largest reservoirs on earth the ice sheets and the oceans since the latest of these oscillations the last glacial maximum between about 30 000 and 19 000 years ago approximately 50 million cubic kilometres of ice has melted from the land based ice sheets raising global sea level by approximately 130 metres such rapid changes in sea level are part of a complex pattern of interactions between the atmosphere oceans ice sheets and solid earth all of which have different response timescales the trigger for the sea level fluctuations most probably lies with changes in insolation caused by astronomical forcing but internal feedback cycles complicate the simple model of causes and effects

characteristics of soil water movement in a grass slope in a karst peak cluster region china soil water is very important in hilly areas with thin soil layers and deep groundwater tables such as the karst peak cluster region of southwest china an investigation into soil water movement can provide insights into management of shallow water resources and soil nutrients as well as prevention of groundwater pollution in this study o 18 and h 2 tracers were used to trace soil water movement in planar soil mass type microhabitats in the middle part of a steep hillslope covered by grasses in a karst peak cluster region of china from may 2008 to july 2009 samples of precipitation and two types of soil water which had different integrated degrees of mobility and were of different depth intervals or depths were collected the hydrogeochemical characteristics were compared between precipitation and soil water and these data were applied in convolution based lumped parameter models our results indicated that vertical piston flow rather than lateral flow along the soil bedrock interface played an important role in soil water percolation at least in the upper soil layer approximately 7cm over the permeable bedrock the mixing effect and preferential flow might also play a role in soil water percolation in general the evaporation effect on soil water was weak except for the uppermost 10cm soil matrix water during winter the lower limits of mean transit time of soil matrix flow passing through 5 15 25 35 and 41 5cm depths were 4 81 7 70 16 19 21 85 and 27 44days respectively our study demonstrated the crucial functions of the soil reservoir in regulating the water cycle and could provide guidance on conservation of soil water and hydrological studies the applied method was proved to be a suitable approach for investigating soil water movement on a monthly scale

review on soil water isotope based groundwater recharge estimations groundwater recharge estimations are necessary for sustainable management of groundwater resources among various hydraulic hydrogeological and hydrological approaches tracer methods are proposed to improve groundwater recharge estimations soil water isotope based estimates of groundwater recharge rates were developed in the 1960s and have been applied in more than 40 studies reviewed within this manuscript this comprehensive review research distinguishes three fundamental research approaches 1 labelling method with tritium or deuterium which can be used to trace unsaturated zone water movement 2 tracing soil water movement using a seasonal signal of stable isotopes in precipitation mainly applied in humid zones and 3 interpretation of an evaporation signal that impacts soil water stable isotope composition mainly applicable in arid and semiarid regions more recently advances in soil water extraction and analytical methods allow a higher sampling resolution and in situ measurements of soil water stable isotopes analytical advances may strengthen and improve the applicability of stable isotope methods for quantitative recharge we present compare and discuss studies of unsaturated zone isotope profiles with an emphasis on necessary prerequisites such as a substantial thick porous sedimentary layer or negative influences through high clay and silt contents or dry soil conditions copyright 2015 john wiley sons ltd