bluuebunny/crossref_metadata_2025_split huggingface dataset:
The survival of desert varnish in subsurface positions, western New South Wales, Australia
Authors: Dragovich D. 
Published: February 2007

AbstractDesert varnish occurs in arid western New South Wales. Microprobe analysis has shown that the chemical composition of this varnish lies within the ranges reported for varnish in United States. Field observations suggest that desert varnish near the soil surface may be destroyed by weathering, but that varnish at depths of more than 15 cm can survive burial and later be exhumed. Varnish has also survived coating by calcium carbonate; a corrected age of about 5000 years for the carbonate indicates long‐term persistence of varnish under this form of ‘burial’. In some situations, presently‐exposed varnish may have a complex history of burial and exhumation following initial subaerial formation.
Drop shape and erosivity part I: Experimental set up, theory, and measurements of drop shape
Authors: Epema Gerrit F. , Riezebos Hans Th. 
Published: February 2007

AbstractSimulated raindrops falling in still air have a shape that is mainly determined by surface tension and hydrostatic pressure. Drops released from capillary tips show an initial shape variation ranging from prolate to oblate but eventually this oscillation is damped. At terminal velocity drops have attained equilibrium and have an oblate shape. Measurements of the shape of simulated rain drops produced by capillary tubes were made using a simple, newly‐developed photographic set up. The measurements showed that models describing the oscillation frequency and amplitude of drops falling at terminal velocity can also be applied to the simulated drops. A comparison is made between the shape of raindrops in natural storms and simulated drops. Recommendations are given regarding fall heights in simulation in relation to the drop shape in nature.
The stratigraphy of flandrian relative sea‐level changes at a site in tayside, Scotland
Authors: Smith D. E. , Dawson A. G. , Culungford R. A. , Harkness D. D. 
Published: February 2007

AbstractPeat deposits in a gully at the inland margin of the Firth of Tay carselands contain a transgressive wedge of estuarine sediments laid down at the culmination of the Main Postglacial Transgression. In previous work, the sequence of deposits in the gully and their age have been examined at one location. The present study both extends and evaluates that previous work, employing further field work and laboratory analyses. The detailed stratigraphy of the deposits is identified, whilst from a borehole close to the limit of the transgressive deposit, diatom analysis and geochemical analyses, involving the determination of Al, Mg, C, and δ 13CPDB are outlined. Eight 14C assays from peat at the transgressive and regressive contacts in four boreholes along the wedge of estuarine sediments are described. Whilst the results of diatom analysis are inconclusive, the geochemical analyses indicate that the sediment accumulated broadly continuously without major changes in the depositional environment. It is concluded that the Main Postglacial Transgression in the gully was at first rapid, then slowed and culminated between 6240 ± 80 and 6030 ± 80 (or 6170 ± 90) radiocarbon years, B.P. It is subsequently maintained that the geochemical analyses described here may be of value in determining the continuity of transgressive deposits, whilst the practice of obtaining multiple radiocarbon assays at such locations should enable assessment of age to be refined. This may in turn assist in testing the hypothesis of shoreline diachroneity in glacioisostatically affected areas.
210Pb dating of scottish lake sediments, afforestation and accelerated soil erosion
Authors: Battarbee Richard W. , Appleby Peter G. , Odell Kevin , Flower Roger J. 
Published: February 2007

AbstractChanges in the rate of soil erosion in lake catchments can be identified from changes in the rate of sediment accumulation in lakes. Here we compare recently afforested sites with non‐afforested sites in the Galloway area of Southwest Scotland. We show that lakes with non‐afforested catchments have slow, constant sediment accumulation rates, whereas lakes with recently afforested catchments have changes in accumulation that parallel the known history of afforestation. For Loch Grannoch the sediment accumulation rate increases from 0.1 cm yr−1 to over 2 cm yr−2 during the disturbance period. Data from L. Skerrow, however, suggest that the rate might decline to predisturbance levels after approximately 10 years as the forest canopy closes and drainage channels stabilize.
Human influence upon sedimentation in Llangorse Lake, Wales
Authors: Jones R , Benson‐Evans K. , Chambers F. M. 
Published: February 2007

AbstractPalaeolimnological studies at Llangorse Lake, Wales, constitute part of the British contribution to IGCP Project 158 (The Palaeohydrology of the Temperate Zone in the Last 15000 Years). The lake has been adopted as the Reference Site for the South Wales region under Subproject 158B (Lake and Mire Environments) and is located in the Reference Area for Britain: the Severn Basin.Results of biological, physical, and multielement chemical analyses on a 12.35 m Livingstone core are presented and compared with previous analyses on short Mackereth cores taken from two troughs in the lake basin. Human impact upon post‐glacial sedimentation is assessed with reference to sediment chemistry, physical properties, and sedimentation rates, based on relative pollen,14C, and210Pb dating. Vegetational history of the catchment is inferred from a pollen diagram for a section of the core fromc. 8 to 6.75 m depth in which evidence for human impact is first apparent. Water content, loss on ignition, and carbonate content are presented for the whole core; density, water content, loss on ignition, carbonates, and elemental analyses of P, Ca, Mg, K, Ti, Al, Fe, and Mn for the interval 6 75 and 8.25 m depth.Sedimentation rates were low during Boreal and Atlantic times (c. 9000‐ 5000 BP), rose significantly from the time of the elm decline (estimated at 5000 BP) and increased further atc. 1800 BP when nekron muds were succeeded by deposition of silty clay. Inferred rates of erosion of soils from the catchment are discussed and related to sediment chemistry.
An improved method of aggregate stability measurement
Authors: Farres P. J. , Cousen S. M. 
Published: February 2007

AbstractThe stability of individual soil aggregates to impacting water drops is now regarded as a fundamental parameter required in any soil erodibility assessment. This stability has been measured by the use of single drop rainfall simulators, the characteristics and operation of which have, in the past, shown considerable variation. The drop sizes, impact frequency, drop fall height, chemistry of drop‐forming liquid, aggregate pretreatment, and definition of breakdown affect the way in which the apparatus can be used to define stability. Within this paper each one of these characteristics is considered and a piece of apparatus proposed which is believed to give results with increased consistency and replicability. The described apparatus can be readily reproduced in any laboratory situation, and has the added advantage of being not only appropriate for the measurement of indices of stability, but also of providing an environment in which the mechanisms of aggregate breakdown can be investigated.
Detrended correspondence analysis of heathland vegetation: The identification of runoff contributing areas
Authors: Gurnell A. M. , Gregory K. J. , Holus S. , Hill C. T. 
Published: February 2007

AbstractDetrended correspondence analysis is applied to information on vegetation composition for the heathland zone of a New Forest catchment. A map of runoff contributing areas is constructed from a soil moisture related gradient in the vegetation data and the resulting map compares favourably with other information on runoff contributing areas in a subcatchment.
Spatial variability and variations in bedload transport direction in a subtidal channel as indicated by sonographs
Authors: Goedheer G. J. , Misdorp R. 
Published: February 2007

AbstractThree sonographs of a part of a subtidal channel, located in the Oosterschelde, are described and interpreted. The sonographs are used to determine the asymmetry of the bedforms. Current profiles and directions are used to explain differences in dimensions and characteristics of the bedforms. The relations between current velocity parameters and bedform characteristics in intertidal zones do not apply to subtidal forms. The division in the depth‐velocity diagrams between the types of 2d and 3d bedforms of Dalrymple et al. (1978) is not valid.
Sediment variability and bed material sampling in gravel‐bed rivers
Authors: Mosley M. P. , Tindale D. S. 
Published: February 2007

AbstractIn a 350 m wide reach of the braided, gravel‐bed Ashley River, the surface layer of the bed material was sampled in 141 areas of homogeneous graded sediment along seven cross‐sections, and 30 kg bulk samples were collected at 86 randomly selected locations along the cross‐sections. At one location, a single 854 kg sample composed of 28 subsamples was also collected.Analysis of the single large sample indicate that accurate determination of mean grain size D at that site requires, desirably, a sample of ∼ 100 kg, but that samples in which the weight of the largest stone is less than 5 per cent of the total weight have unbiased estimates of D. Spatial variability of bulk material is such that 228 and 50 samples are needed to estimate D to ± 10 and ± 20 per cent respectively of the true value; requirements for estimating inclusive graphic standard duration are only 11 and 3 respectively.The grain‐size distribution of the surface layer is only weakly related to the bulk material beneath. The results of ‘Wolman sampling’ along 12 cross‐sections at two pace intervals (average 120 stones per cross‐section) indicate that estimation of overall surface D to ±10 and ±20 per cent would require sampling along 64 and 14 cross‐sections respectively.It is concluded that accurate characterization of bed sediment in gravel‐bed rivers is very demanding of labour and resources, and that careful planning is needed to ensure efficiency and meaningful results.
Estimation of soil loss at a regional scale based on plot measurements—some critical considerations
Authors: Roels J. M. 
Published: February 2007

AbstractThe paper is prompted by apparent deficiencies in the design of plot studies in regional erosion surveys. The principal shortcomings of observational erosion research have been poor sampling design and inadequate analyses of data. The paper identifies various sources of bias which must be taken into account before plot data can be extrapolated to land units in a regional survey. Judging from soil loss data of a case‐study in the Ardèche rangelands one may conclude that even accurate plot measurements can still be rather a rough basis for regional erosion assessment. Finally, the paper highlights strategies that might be used to improve erosion sampling.
The downstream gradation of particle sizes in the Squamish river, British Columbia
Authors: Brierley Gary J. , Hickin Edward J 
Published: February 2007

AbstractThe exponential downstream decline in particle size predicted by Sternberg (1875) is examined within a highly active alpine fluvial environment, the gravel‐bed Squamish River in southwestern British Columbia. Transect survey procedures for sampling within the coarse alluvial gravels are described in detail. Downstream trends for various particle size statistics, plotted with distance from a major sediment source, are considered according to two scenarios. Evaluation of overall trends indicates that the downstream expression derived by Sternberg (1875) is not the most appropriate; rather, curves are better described by power functions. This reflects a very rapid decline in particle size immediately downstream of the major sediment source. Secondly, evaluation of downstream trends in relation to channel planform determines that exponential functions with different coefficients describe adequately relations within individual planform reaches. There is insufficient evidence to suggest which of these two scenarios may be appropriate. Several lines of evidence suggest that the trends found are more the result of selective sediment transport phenomena than of abrasion, a condition attributed to channel competence within a system dominated by sediment‐supply conditions.
A study of dells in the new forest, Hampshire, England
Authors: Tuckfield Cyril G. 
Published: February 2007

AbstractDells in the New Forest are described as amphitheatre‐shaped hollows, perched on valley sides, sometimes singly, in other places in groups tributary to small dry valleys. They have steep rear walls and sides, flatfish floors, and convex lips, usually without any water‐worn channels. The slopes on which they occur, cut in Eocene sands and clays, have been subjected to solifluction, and this has produced wide gently sloping terraces at the foot of the hillside. Superficial deposits within the New Forest dells are divided into two groups by process: a lower head of fragmented flints in a sandy or clayey matrix, assigned to Zone III; overlying colluvial deposits including slumped material and slope wash, dated by reference to a buried soil to Zone VIIa. Although scoured by solifluction, other processes probably account for the initial formation of the hollows, and nivation is suggested. The dells are compared with the chalk coombes of southern England and the dellen of European and other writers. A possible chronology is suggested for the New Forest dells.
Arsenic in the Yellow river, China
Authors: Runhua Huang 
Published: February 2007

AbstractData collected since 1973 show high levels of arsenic in the Yellow River, very largely from natural sources. Average and peak concentrations, and the downstream distribution of the arsenic suggest the most likely source as the loess which provides 90 per cent of the river's suspended load. Arsenic is strongly absorbed by the silt and clay in the river: some of it is deposited in reservoirs and delta sediments but most is carried out to sea.
Timing the transport of water through the upper vadose zone in a Karstic system above a cave in Israel
Authors: Even H. , Carmi I. , Magaritz M. , Gerson R. 
Published: February 2007

AbstractChemical and isotopic analysis of karst water dripping over a one year period from seeps in a cave above the Cenomanian aquifer in the Judea hills of Israel lead to several conclusions: (i) The tritium ages and the chemical composition of water from different seeps in a karstic cave vary greatly, (ii) The reservoirs in the upper part of the vadose zone hold water for up to several decades, (iii) Some of the cave seeps are mixtures of the old and more recent meteoric water from paths of different length, (iv) The history of storm events can only be traced in some of the seeps, (v) For most dripping seeps there is no immediate response of seepage discharge to the rainfall intensity and quantity—i.e. the seepage discharge is fairly constant.
Peat slides in Teesdale and Weardale, northern pennines, july 1983: Description and failure mechanisms
Authors: Carling P. A. 
Published: February 2007

AbstractPeat landslides that occurred in Upper Teesdale and Weardale in 1983 are described. The slides occurred after thunderstorm rainfall of a very rare intensity and return period. The slope geomorphological features and the vegetation associated with the slide areas are detailed.Baseline geotechnical data are used in a simple retrospective stability analysis, treating the peat slides as shallow translational slips. The analysis demonstrates the probable important role played by open moor drains, natural soil pipes, and prior cracking of the peat (owing to dessication or slow mass movement) in the rapid transfer of water to the failure zone within an impervious sensitive clay beneath the peat.The frequency of peat landslides and the visual persistence of sites is considered briefly in relation to substratum and peat stability within a context of climatic change. It is suggested that there may be a gradation of type from the classic Irish bog‐burst, through failures of intermediate character, to peat slips involving rigid peat blocks. Antecedent conditions and the mechanism of failure need not be similar for mass movements at either end of this spectrum.
A re‐examination of the evidence for a Plio‐Pleistocene marine transgression on the Chiltern Hills. III. deposits
Authors: Moffat A. J. , Catt J. A. 
Published: February 2007

AbstractA petrological re‐examination of the deposits that Wooldridge and Linton used as evidence for a Plio‐Pleistocene marine transgression on the Chiltern Hills indicates that many are fluvial and some have been reworked in a periglacial climate. However, those from Little Heath and Rothamsted, Hertfordshire and Lane End, Buckinghamshire are confirmed as marine and Plio‐Pleistocene. Subsidence during the Pleistocene is suggested by the northeasterly decline in height of the few truly marine deposits.
The occurrence on carboniferous coal of anthropogenic origin in the contemporaneous Vistula river sediments near Cracow (Southern Poland)
Authors: Rutkowski J. 
Published: February 2007

AbstractCarboniferous pit coal is the most important anthropogenic component of the contemporaneous Vistula river gravels and sands with individual fractions containing from 10 to 98 per cent coal fragments. Coal concentration is connected with differences in the bulk density between coal and other gravel components. The lower sediments date from the first half of the nineteenth century when the coal began to appear in large quantities in the Vistula channel. The presence of coal is also an indicator of the depth of channel sediment reworking during floods in the nineteenth and twentieth centuries.
A physically‐based model of the dispersion of splash droplets ejected from a water drop impact
Authors: Wright Andrew C 
Published: February 2007

AbstractA model has been developed which predicts the dispersion of splash droplets produced by the impact of a water drop on a sloping soil surface.Experimental results of the ejection velocities and ejection angles of the splash droplets are generalized to a planar slope and the resulting splash distances are calculated taking into account the effects of air resistance. The predictions are presented in terms of the numbers of splash droplets from the impact point to surrounding squares arranged in a grid on the slope.The model explains many experimentally observed features of raindrop splash in terms of the mechanics of the processes involved and can make predictions of the effects of slope, wind, raindrop size, and soil properties on droplet dispersion. The component of the raindrop velocity parallel to the surface of the slope is identified as the main factor determining the degree and the direction of the asymmetry in the splash droplet dispersion.By combining the model with a theory of the entrapment of soil in the splash droplets it is possible to extend it to predict the dispersion of soil particles by raindrop impact, which is the basis of a model of soil erosion by rainsplash.
14C dating and palaeoenvironment of the historic ‘little ice age’ glacier advance of Nigardsbreen Southwest Norway
Authors: Matthews John A. , Innes John L. , Caseldine Christopher J. 
Published: February 2007

AbstractMoss and grass remains associated with a well‐developed in situ palaeosol buried beneath a moraine ridge in front of Nigardsbreen (Jostedalsbreen ice cap, southern Norway) have been 14C‐dated. Pollen preserved with the plant remains suggests the existence of an agricultural landscape prior to the deposition of the moraine. The calibrated dates and the pollen spectra are in close accord with historically‐documented evidence for the timing and palaeoenvironment of the ‘Little Ice Age’ advance of the glacier. Considerable potential is indicated for estimating the maximum ages of moraine ridges and for palaeoenvironmental reconstruction where such documentary evidence does not exist.
Infiltration‐excess caused by Stemflow in a cyclone‐prone tropical rainforest
Authors: Herwitz Stanley R. 
Published: February 2007

AbstractTropical rainforest canopy trees that have large projected areas of upwardly inclined branches are capable of funnelling large volumes of rainwater down their trunks. During periods of prolonged heavy rainfall on Mount Bellenden Ker in northeast Queensland, Australia, stemflow volumes were found to be as much as two orders of magnitude greater than the volume of incident rainfall expected in a rain gauge occupying an area equal to the trunk basal area. Stemflow totals ranging from 6000 to 70000 litres were generated by individual trees from 7800 mm of rainfall over two successive wet seasons.The combination of high intensity rainfall and the funnelling effect results in significant quantities of infiltration‐excess at the ground surface. Stemflow fluxes as high as 31.4 cm3 min−1 per cm2 of basal area (i.e. the equivalent of 314 mm min−1) were recorded when rainfall intensity was only 2 mm min−1. The mean infiltration capacity of the topsoil was determined to be 6.2 mm min−1. The areas over which the stemflow would have had to spread in order to infiltrate were computed to be as much as 3 m2 around the bases of individual canopy trees. Approximations of the distances that the infiltration‐excess would have travelled away from the tree bases were calculated by assuming that the infiltration area either expands radially outward in the form of an annulus or extends straight downslope from the tree base.
Contemporary and palaeo channel patterns and the late quaternary stratigraphy of Cooper Creek, Southwest Queensland, Australia
Authors: Rust Brian R. , Nanson Gerald C. 
Published: February 2007

AbstractBraided and anastomosing channels make up two major coexistent networks in the mud‐dominated fluvial system of Cooper Creek, Southwest Queensland. The floodplain is characterized by a system of mud braids operative when floods inundate the whole alluvial surface. Anastomosing channels are inset deeper into the floodplain, operate at modern flows, and transport a traction load of sand.Shallow stratigraphic data show that an underlying sand sheet is unrelated to surface channel patterns and was formed by a system of meandering streams. According to preliminary dates based on thermoluminescence, the change from a sand‐ to mud‐dominated fluvial regime took place between 50 000 and 200 000 years B.P., and probably reflects increasing aridity.
A quantitative soil‐stratigraphic approach to the correlation and dating of post‐glacial river terraces in Glen Feshie, western Cairngorms
Authors: Robertson‐Rintoul M. S. E. 
Published: February 2007

AbstractLittle is known about Holocene river terrace development in upland Scottish valleys. Interpretation of many of the terrace sequences, previously suggested to have been formed by meltwaters either from the last Scottish ice sheet or the Loch Lomond Advance, has generally been based on morphological data. In this paper an alternative approach to the traditional height‐based method of terrace correlation and dating is presented using data from Glen Feshie, western Cairngorms. Terrace fragments are numerically classified and objectively grouped using quantitative soil‐stratigraphic data. Principal Components Analysis is used to both quantify pedological data and separate temporal trends in the data from variance due to local site factors. The scores on the temporal component are used to derive soil‐stratigraphic units developed on the surficial sediments of the Glen Feshie terraces by grouping soil sites using a hierarchical clustering technique. This provides evidence for at least five soil‐stratigraphic units developed on the fluvial surfaces. Various methods of absolute dating control permits association of these surfaces with five phases of terrace development. These are placed tentatively at 13 000, 10 000, 3600, 1000, and 80 radiocarbon years B.P., suggesting at least three phases of valley floor incision in Glen Feshie during the late Holocene.