seismic pore space compressibility and gassmann s relation the pore space compressibility of a rock provides a robust model independent descriptor of porosity and pore fluid effects on effective moduli the pore space compressibility is also the direct physical link between the dry and fluid saturated moduli and is therefore the basis of gassmann s equation for fluid substitution for a fixed porosity an increase in pore space compressibility increases the sensitivity of the modulus to fluid substitution two simple techniques based on pore compressibility are presented for graphically applying gassmann s relation for fluid substitution in the first method the pore compressibility is simply reweighted with a factor that depends only on the ratio of fluid to mineral bulk modulus in the second technique the rock moduli are rescaled using the reuss average which again depends only on the fluid and mineral moduli

the history of danube loess research the loess paleosol sequences of the danube basin contain the longest and most complete terrestrial records of middle and late pleistocene paleoclimates in europe consequently it is no surprise that scientific research into european loess began in this region and has a long and distinguished history european loess research was initiated by count marsigli in the serbian vojvodina in the late 17th century formed the focus of the international loess commission which straddled both sides of the iron curtain from 1961 and culminated with george kukla s seminal studies in the 1970s correlating the loess archives with deep sea sediments the rise in popularity of the longer chinese loess sequences in the early 1980s shifted the international research focus away from europe and it was not until the change of century that scientific investigation intensified in the region this time with much more sophisticated tools for analysis despite its potential as one of europe s most valuable quaternary archives scientific research into danube loess has until recently been hindered both by landscape heterogeneity and the large number of countries it covers these have presented a major limiting factor in developing a unified research approach for decades regional national loess stratigraphic models were defined separately difficulties in correlating such schemes persist especially since these often change significantly with advances in dating methodologies a cooperative effort is necessary to synthesize the available data which requires not only the insights from but also the perspective provided by an appreciation of the history of the research in this study we present a critical historical overview of loess research in the danube region we classify the major research phases throughout the long tradition of danube loess investigations into five categories 1 the early period late 17th century until 1920 extending from marsigli to penck 2 the classic period 1920 1961 encompassing the contributions of milankovic and the development of pedostratigraphy 3 the modern period 1961 present which oversaw czech innovations and developments in geochronologic methods in particular amino acid racemisation aar and luminescence dating and 4 contemporary research from bronger s unified pedostratigraphy to orbitally tuned timescales finally 5 we present a vision of future danube loess research

optical dating of romanian loess a comparison between silt sized and sand sized quartz abstract the loess palaeosol sequence near mircea vod dobrogea se romania is thought to comprise at least five glacial interglacial cycles it is considered as one of the most significant records of late quaternary environmental and climatic change in the region age information for the sequence was previously obtained through time depth modeling of magnetic susceptibility data and optically stimulated luminescence dating osl of fine silt sized 4 11 m quartz this study documents the granulometric properties of the sequence and compares the osl characteristics and age of fine sand sized 63 90 m quartz to those of silt sized quartz osl signals from both sand and silt sized quartz are dominated by a thermally stable fast decaying component a suite of laboratory test confirms that the single aliquot regenerative dose sar protocol is suitable for these samples each grain size fraction yields a set of optical ages that is consistent with the stratigraphic position of the samples the ages obtained using sand sized grains however are up to 70 higher than those obtained using silt sized quartz the discrepancy in age results is not understood as according to procedural tests the osl signal from both fractions should be suitable for dating the deposits as such it cannot be established whether the uppermost weakly developed palaeosol was formed during mis3 or mis5 and if the rate of loess accumulation varied during the last glacial only by using standard sar osl techniques both sets of ages do confirm however that the first well developed palaeosol s1 is of last interglacial age

rapid and cyclic aeolian deposition during the last glacial in european loess a high resolution record from nussloch germany abstract this paper reports the results of an investigation of the weichselian upper pleniglacial loess sequences of nussloch rhine valley germany based on stratigraphy palaeopedology sedimentology palynology malacology and geochemistry 13 c supported by radiocarbon tl and osl dating grain size and magnetic susceptibility records are taken at 5 cm intervals from the upper pleniglacial upg loess the data indicate cyclic variations in loess deposition between ca 34 and 17 ka when the sedimentation rate is especially high 1 0 1 2 m per ka for more than 10 m the grain size index gsi ratio of coarse silt versus fine silt and clay shows variations which are assumed to be an indirect measurement of wind intensity the sedimentation rate interpreted from the profiles indicates high values in loess loess events le 1 to le 7 and low or negligible values in tundra gley horizons g1 to g8 osl ages from the loess and 14 c dates from organic matter in the loess show that loess deposition was rapid but was interrupted by shorter periods of reduced aeolian sedimentation comparison between the data from nussloch and other european sequences demonstrates a progressive coarsening of the loess deposits between ca 30 and 22 ka this coarsening trend ends with a short but major grain size decrease and is followed by an increase to a new maximum at 20 2 ka w shape correlation between the loess gsi and the greenland ice core dust records suggests a global connection between north atlantic and western european global atmospheric circulation and wind regimes in addition the typical upper pleniglacial loess deposition begins at ca 30 31 ka close to heinrich event he 3 and the main period of loess sedimentation at about 25 2 ka is coeval to he 2 correlation of magnetic susceptibility and grain size records shows that the periods characterised by high gsi coincide with an increase in the amount of ferromagnetic minerals reworked from the rhine alluvial plain they suggest enhancement in the frequency of the storms from n nw these results are integrated within a palaeogeographical model of dust transport and deposition in western europe for the weichselian upper pleniglacial or late pleniglacial

groundmass crystallization of mount st helens dacite 1980 1986 a tool for interpreting shallow magmatic processes the 1980 1986 eruption of mount st helens volcano provides an unprecedented opportunity to observe the evolution of a silicic magma system over a short time scale groundmass plagioclase size measurements are coupled with measured changes in matrix glass plagioclase and fe ti oxide chemistry to document increasing groundmass crystallinity and thus to better constrain proposed physical models of the post may 18 1980 magmatic reservoir measurements of plagioclase microlite and microphenocryst sizes demonstrate that relatively rapid growth approximately 10 9 cm s of groundmass plagioclase occurred immediately subsequent to may 18 relatively rapid plagioclase growth continued through the end of 1980 at an average rate of 3x10 11 cm s plagioclase growth rates then decreased to 1x10 11 cm s through 1986 changes in groundmass crystallinity are reflected in changes in both matrix glass and plagioclase microphenocryst rim chemistry although the matrix glass composition appears to have remained approximately constant from 1981 1986 after a rapid compositional change from may 18 until the end of 1980 plagioclase microphenocrysts show increasingly more complex zoning patterns with time microphenocryst core compositions are commonly positively correlated with crystal size both of these observations indicate continuous groundmass plagioclase growth through 1986 magmatic temperatures estimated from fe ti oxide pairs are approximately constant through 1981 at eruption temperatures of 930 c and at log fo2 of 10 8 by 1985 1986 oxide temperatures decreased to 870 c chemical and textural changes can be explained by 1 rapid degassing and crystallization in response to the intrusion of magma into a shallow 4 5 km reservoir toward the end of the may 18 1980 eruption 2 continued crystallization at a much reduced rate through 1986 due to slow cooling of the shallow magma reservoir growth rates and consequent chemical changes appear to decrease at the end of 1980 this is coincident with the change in eruption style from explosive eruptions sometimes followed by dome growth to solely extrusive dome building events and can be explained by the expected viscosity increase of both degassing and increasing crystallinity the model of twostage crystallization of magma in a shallow reservoir is consistent with conclusions from gas studies casadevall et al 1983 gerlach and casadevall 1986 a b patterns of crater deformation chadwkck et al 1988 and post 1980 seismicity endo et al 1990 although it does not explain the experimental data of hill and rutherford 1989 on the growth rate of amphibole reaction rims textural measurements on mount st helens dacite can also be used to evaluate crystallization kinetics in silicic magmas systems for which experimental data is almost non existent plagioclase growth rates are 5 10 times slower than estimated plagioclase growth rates in basaltic systems a result consistent with the higher viscosity of a more silicic melt furthermore patterns of textural change both average crystal size and number density are similar to those observed during the 1984 mauna loa eruption by lipman and banks 1987 suggesting that the only modification to the crystallization behavior of plagioclase required in extrapolation from basaltic systems is a moderate decrease in rates such that the rate of crystallization scales with the melt viscosity

crystal size distribution csd in rocks and the kinetics and dynamics of crystallization crystal size distributions csds measured in metamorphic rocks yield quantitative information about crystal nucleation and growth rates growth times and the degree of overstepping t of reactions during metamorphism csds are described through use of a population density function n dn dl where n is the cumulative number of crystals per unit volume and l is a linear crystal size plots of ln n vs l for olivine pyroxene and magnetite in high temperature 1000 c basalt hornfelses from the isle of skye define linear arrays indicating continuous nucleation and growth of crystals during metamorphism using the slope and intercept of these linear plots in conjunction with growth rate estimates we infer minimum mineral growth times of less than 100 years at t 10 c and nucleation rates between 10 4 and 10 1 cm3 s garnet and magnetite in regionally metamorphosed pelitic schists from south central maine have csds which are bell shaped we interpret this form to be the result of two processes 1 initial continuous nucleation and growth of crystals and 2 later loss of small crystals due to annealing the large crystals in regional metamorphic rocks retain the original size frequency distribution and may be used to obtain quantitative information on the original conditions of crystal nucleation and growth the extent of annealing increases with increasing metamorphic grade and could be used to estimate the duration of annealing conditions if the value of a rate constant were known finally the different forms of crystal size distributions directly reflect differences in the thermal histories of regional vs contact metamorphosed rocks because contact metamorphism involves high temperatures for short durations resulting csds are linear and unaffected by annealing similar to those produced by crystallization from a melt because regional metamorphism involves prolonged cooling from high temperatures primary linear csds are later modified by annealing to bell shapes

a remarkable late saalian mis 6 loess dust accumulation in the lower danube at harletz bulgaria abstract while numerous high resolution studies concerning last glacial aeolian sequences are available for europe the approach of the penultimate glacial in this geographical area is still poorly developed in order to bridge this gap this study focuses on the bulgarian sequence of harletz along the danube river where extremely high sedimentation rates allow the depiction of high resolution signals during mis 6 at harletz in nw bulgaria on the western bank of the ogosta river tributary of the danube a 20 m thick loess palaeosols section was cleaned and sampled for a multi disciplinary study and detailed pedostratigraphic approach high resolution continuous bulk sampling 5 cm was carried out to characterise sedimentary grain size magnetic properties including magnetic susceptibility and its frequency dependence colour reflectance 1 cm and organic carbon geochronological control is based on 16 samples collected for osl and met pirir dating using a cyclo stratigraphic approach of the sequence combined with dating constraints provided by both met pirir dates and the age of a tephra layer occurring at a depth of 12 m within the main loess unit we can demonstrate that the harletz section exhibits a 10 m thick late saalian marine isotope stage 6 mis 6 loess accumulation unique in europe the lower part of the main loess unit is 4 m thick and overlies a basal brown soil complex allocated to mis 7 which includes an exceptionally thick 4 m and detailed succession of loess and four incipient soil horizons never described in european loess until now the closest and best dated high resolution palaeoenvironmental archive suitable for comparison comes from lake ohrid located about 400 km to the sw of harletz the ohrid palynological record shows a progressive step by step evolution in climate and in environmental change during the transition between mis 7 and mis 6 from which a parallel with the harletz pedosedimentary succession can be proposed during the younger part of mis 6 160 129ka steppe vegetation with abundant herbs artemisia is dominant in the lake ohrid record in good accordance with a global enhancement of aeolian dynamics especially well recorded in sections located close to the danube river from serbia to bulgaria and romania l2 loess according to interpretations stemming from this study the silts and fine sands building the harletz loess section would have been transported from the danube braided river system located at that time at about 4 5 km to the nw based on our data the main loess units are characterised by a very low to a total absence of coarse sand particles by contrast during the eemian interglacial mis 5e and to a lesser extent throughout mis 5 and during mis 3 interstadials the long distance transport of silt and fine sand particles is stopped and a weak aeolian sedimentation is likely driven by north easterly winds transporting coarse sand grains from the proximal ogosta river sandy banks finally the weak development of last glacial loess 4 m max likely results from a rapid infilling of the sedimentary trap during the saalian then followed by a strong anthropogenic erosion of the topsoil and of the upper part of the loess profile since the early holocene neolithic

towards identifying the origin of metamorphic components in austrian loess insights from detrital rutile chemistry thermometry and u pb geochronology abstract trace element cr nb zr geochemistry and u pb geochronology of detrital rutile grains provide constraints on the nature of potential metamorphic sources of loess in austria cr and nb compositions reveal rutile sources with a predominance of metapelitic lithologies for all three loess samples by contrast zr in rutile geothermometry indicates that formation temperatures for loess rutiles around krems at the bohemian massif bm proved to be ca 100 125 c higher t median 717 and 737 c for two samples from stratzing and krems than those at wels close to the eastern alps ea t median 612 c implying that rutiles in loess at wels were derived from alpine lower amphibolite grade rocks while those in loess around krems from rocks formed under upper amphibolite to granulite grade conditions metamorphic temperatures recorded in rutiles from loess at the bm closely match the two reaction thermobarometry estimates of the last high t overprint 7 11 kbar and 700 800 c of rocks making up the varied series and gfohl units around krems this event dated at 340 to 350 ma is believed to be captured by the detrital rutile u pb data as well e g 349 21 and 352 32 ma all these data demonstrate the significance of proximal bm sources varied series and gfohl unit drained by the danube in loess formation around krems fluvial transport is believed to have played a substantial role in entraining and accumulating rutiles for subsequent aeolian deflation for loess near wels while the ultimate sources of these grains are likely to be in the eastern alps the recycling of these rutiles from the flysch zone of the ea cannot be ruled out despite the uncertainties of cr nb based source discriminations in some cases and the potential decoupling of zr and u pb systematics recognized in rutiles this study demonstrates that rutiles may provide unique details on the nature and metamorphic history of their parent rocks if used with caution and by knowing its limitations under certain conditions it is anticipated that beyond zircon rutile geochemistry will become a powerful provenance tracer in loess studies too this seems to be particularly important to gain a better understanding on the erosion and rutile fertility of different metamorphic terrains and their contributions to loess material issues that have not been adequately addressed thus far

fine and coarse quartz sar osl dating of last glacial loess in southern romania abstract previous single aliquot regenerative optically stimulated luminescence sar osl dating studies of representative loess sections in southeastern romania revealed severe discrepancies among the ages obtained on fine 4 11 m and coarse 63 90 m grains of quartz the current study aims at expanding these investigations by extending the area of study to the more westerly loess deposits in the lower danube basin the luminescence properties of the grain sizes of quartz extracted from 18 samples collected from the last glacial loess layer at lunca section wallachian plain are examined and compared investigations confirm the reliability of the sar osl protocol previously applied to romanian loess preheat at 220 c for 10 s cutheat at 180 c and elevated temperature osl despite this the obtained equivalent doses on coarse quartz are higher than those obtained on fine material for most samples as in the case of our previous studies these results into fine quartz osl ages that are significantly lower compared to the coarse quartz age results however the ages obtained for the uppermost two samples are in very good agreement ages spanning from 19 2 ka to 43 4 ka on fine quartz and from 20 2 ka to 54 6 ka on coarse quartz have been obtained for the loess deposited during last glacial period based on the fine as well as the coarse quartz chronology significantly low sedimentation rates were computed for the last glacial maximum period and mis 3 osl ages and magnetic susceptibility measurements indicate that the loess layer corresponding to the early glacial period mis 4 is very thin at this site and affected by pedogenesis regarding the investigation into the cause of the observed age discrepancy we present evidence through time resolved investigations that the observed behaviour is typical of quartz and cannot be accounted by feldspar contamination we confirm once more that the growth of the osl signal in nature does not correspond to the laboratory generated sar dose response curve that is best described by a sum of two saturating exponential functions the differences observed between the natural and the laboratory dose response for the two quartz fractions are believed to be a cause for the different chronologies reported

crystallization of mount st helens 1980 1986 dacite a quantitative textural approach quantitative measurements of crystal size distributions csds have been used to obtain kinetic information on crystallization of industrial compounds randolph and larson 1971 and more recently on hawaiian basalts cashman and marsh 1988 the technique is based on a population balance resulting in a differential equation relating the population densityn of crystals to crystal sizel i e at steady staten no exp l itg whereno is nucleation density g is the average crystal growth rate is the average growth time and the nucleation ratej nog csd inn vsl plots of plagioclase phenocrysts in 12 samples of mount st helens blast dacite and 14 samples of dacite from the 1980 1986 mount st helens dome are similar and averageg 9 6 1 1 10 3 cm andno 1 2 106 cm 4 reproducibility of the measurements was tested by measuring csds of 12 sections cut from a single sample in three mutually perpendicular directions precision of the size distributions is good in terms of relative but not necessarily absolute values 10 growth and nucleation rates for plagioclase have been calculated from these measurements using time brackets of 30 150 years growth ratesg are 3 10 10 12cm s and nucleation ratesj are 5 21 10 6 cm3 s g andj for fe ti oxides calculated from csd data areg 2 13 10 13 cm sec andj 7 33 10 5 cm3 s respectively the higher nucleation rate and lower growth rate of oxides resulted in a smaller average crystal size than for plagioclase sizes of plagioclase microlites 0 01 mm in the blast dacite groundmass have been measured from backscatter sem photographs nucleation of these microlites was probably triggered by intrusion of material into the cone of mount st helens in spring 1980 this residence time of 52 days gives minimum crystallization estimates ofg 1 3 10 11 cm s andj 9 16 1o3 cm3 s the skeletal form of the microlites provides evidence for nucleation and growth at high values of undercooling t relative to the phenocrysts a comparison of nucleation and growth rates for the two crystal populations phenocrysts vs microlites suggests that while growth rate seems to be only slightly affected by changes in t nucleation rate is a very strong function of undercooling a comparison of plagioclase nucleation and growth rates measured in the mount st helens dacite and in basalt from makaopuhi lava lake in hawaii suggests that plagioclase nucleation rates are not as dependent on composition groundmass textures suggest that plagioclase microphenocrysts crystallized at depth rather than in the conduit in the dome or after extrusion onto the surface most of this crystallization appears to be in the form of crystal growth coarsening of groundmass microphenocrysts at small degrees of undercooling rather than extensive nucleation of new crystals this continuous crystallization in a shallow magmatic reservoir may provide the overpressurization needed to drive the continuing periodic domebuilding extrusions which have been the pattern of activity at mount st helens since december 1980

palaeoclimate records 60 8 ka in the austrian and swiss alps and their forelands abstract the european alps and their forelands provide a range of different archives and climate proxies for developing climate records in the time interval 60 8 thousand years ka ago we review quantitative and semi quantitative approaches for reconstructing climatic variables in the austrian and swiss sector of the alpine region within this time interval available quantitative to semi quantitative climate records in this region are mainly based on fossil assemblages of biota such as chironomids cladocerans coleopterans diatoms and pollen preserved in lake sediments and peat the analysis of oxygen isotopes in speleothems and lake sediment records the reconstruction of past variations in treeline altitude the reconstruction of past equilibrium line altitude and extent of glaciers based on geomorphological evidence and the interpretation of past soil formation processes dust deposition and permafrost as apparent in loess palaeosol sequences palaeoclimate reconstructions in the alpine region are affected by dating uncertainties increasing with age the fragmentary nature of most of the available records which typically only incorporate a fraction of the time interval of interest and the limited replication of records within and between regions furthermore there have been few attempts to cross validate different approaches across this time interval to confirm reconstructed patterns of climatic change by several independent lines of evidence based on our review we identify a number of developments that would provide major advances for palaeoclimate reconstruction for the period 60 8 ka in the alps and their forelands these include 1 the compilation of individual fragmentary records to longer and continuous reconstructions 2 replication of climate records and the development of regional reconstructions for different parts of the alps 3 the cross validation of different proxy types and approaches and 4 the reconstruction of past variations in climate gradients across the alps and their forelands furthermore the development of downscaled climate model runs for the alpine region 60 8 ka and of forward modelling approaches for climate proxies would expand the opportunities for quantitative assessments of climatic conditions in europe within this time interval

coupled european and greenland last glacial dust activity driven by north atlantic climate centennial scale mineral dust peaks in last glacial greenland ice cores match the timing of lowest greenland temperatures yet little is known of equivalent changes in dust emitting regions limiti

krems wachtberg excavations 2005 12 main profiles sampling stratigraphy and site formation abstract since 2005 detailed archaeological investigations have been carried out at the upper palaeolithic site of krems wachtberg in eastern austria where a well preserved gravettian find layer is embedded in an 8 m high late pleistocene loess sequence the excavations are accompanied by interdisciplinary sampling strategies applied on the main profiles entire sediment series as well as on selected locations within the archaeological context the latter include both evident anthropogenic structures an in situ occupation surface with hearths and burials and periglacial features that together determine the morphology and explain the formation of the main gravettian find horizon

towards a revised chronostratigraphy of loess in austria with respect to key sections in the czech republic and in hungary abstract the stratigraphic ages of some well known and characteristic paleosols in austrian and hungarian loess sections have been questioned by several workers since the mid 1970s in particular a generally accepted correlation of austrian and hungarian loess stratigraphies with the well established czech loess stratigraphy has not been put forward this paper presents 41 new thermoluminescence tl dates and the first results from amino acid chronology of key sections in these areas the results are in agreement and suggest a new interregional correlation of loess paleosol sequences for loess older than the last interglacial quartz and feldspar inclusions yield more reliable tl ages than the polymineralic fine grain fraction

hawaiian basalt and icelandic rhyolite indicators of differentiation and partial melting in spite of the voluminous basaltic volcanism on the island of hawaii rhyolite is not produced iceland on the other hand exhibits common rhyolitic volcanism amounting to some 10 12 of its surface rocks this contrast is investigated using the fundamental igneous processes exhibited by sheet like hawaiian lava lakes and shonkin sag laccolith in montana highly differentiated residual melts normally reside within inwardly advancing solidification fronts and are generally inaccessible to eruptive processes only when a large initial phenocryst population is present from which a thick basal cumulate can rapidly form is it possible to supply highly differentiated melt into the active i e eruptable portion of the magma chamber although there is protracted control of differentiation at hawaii by settling of olivine further differentiation occurs within the solidification fronts only by repeated transport and holding is it possible to differentiate beyond the critical composition of the leading edge of the solidification front 7 mgo and 51 5 sio2 crystal size distributions csds for hawaii and shonkin sag are used to demonstrate the inferred physical and chemical processes of solidification including the kinetics of crystallization

quantitative geophysical pore type characterization and its geological implication in carbonate reservoirs abstract this paper discusses and addresses two questions in carbonate reservoir characterization how to characterize pore type distribution quantitatively from well observations and seismic data based on geologic understanding of the reservoir and what geological implications stand behind the pore type distribution in carbonate reservoirs to answer these questions three geophysical pore types reference pores stiff pores and cracks are defined to represent the average elastic effective properties of complex pore structures the variability of elastic properties in carbonates can be quantified using a rock physics scheme associated with different volume fractions of geophysical pore types we also explore the likely geological processes in carbonates based on the proposed rock physics template the pore type inversion result from well log data fits well with the pore geometry revealed by a fmi log and core information furthermore the s wave prediction based on the pore type inversion result also shows better agreement than the greensberg castagna relationship suggesting the potential of this rock physics scheme to characterize the porosity heterogeneity in carbonate reservoirs we also apply an inversion technique to quantitatively map the geophysical pore type distribution from a 2d seismic data set in a carbonate reservoir offshore brazil the spatial distributions of the geophysical pore type contain clues about the geological history that overprinted these rocks therefore we analyse how the likely geological processes redistribute pore space of the reservoir rock from the initial depositional porosity and in turn how they impact the reservoir quality

rock physics based relations for density and s velocity versus p velocity in deepwater subsalt gulf of mexico shales which is commonly used to estimate s wave velocity s from p wave velocity p where the units of velocity are km s and the empirical relations for estimating the shear wave velocity from the compressional wave velocity given by greenberg and castagna 1992 figure 1 compares the relationship between density and sonic velocity for two deepwater subsalt wells in the green canyon area of the gulf of mexico to gardner s predic tion assuming values for parameters a and b given by castagna et al 1993 for sands and shales while the gardner estimate is reasonable for the sands the shales at any given density indicate a significantly lower velocity than that predicted by gardner s relation similarly figure 2 compares p wave versus s wave ve locity data for the same two wells to the prediction of equation 2 and of the greenberg castagna relation for shales it is seen that these relations tend to overestimate s wave velocity for the shales at a given p wave velocity in this paper these discrepancies are investigated using a rock physics model this model not only gives a good descrip tion of the data but also allows the effective pore aspect ratio to be estimated rock physics model to model the elastic moduli of shales the shales were considered as a mixture of clay and quartz with properties taken as those given by carmichael 1989 for quartz and gulf clays han et al 1986 the properties used are listed in table 1 pore spaces were assumed filled by brine having a bulk mod ulus of 3 4 gpa appropriate for the pressure and temperature in the depth range of interest since quartz grains in shales are embedded within a softer continuous clay matrix the elastic moduli of the solid phase were estimated using the hashin sh trikman lower bound hashin and shtrikman 1963 the up per and lower hashin shtrikman bounds for the elastic moduli in table 1 are plotted in figure 3

paleoenvironments from robust loess stratigraphy using high resolution color and grain size data of the last glacial krems wachtberg record ne austria abstract the complex interplay of dust sedimentation pedogenesis and erosion reworking in the formation of loess paleosol sequences lps challenges paleoenvironmental proxies here we show that color and grain size are essential parameters characterizing loess profiles and support robust stratigraphies as a basis for reconstructions in the context of local geo ecological and large scale paleoclimatic evolution detailed paleoenvironmental records from the period since the arrival of anatomically modern humans to the last glacial maximum are scarce in the alpine surroundings the c 7 5 m thick lps krems wachtberg ne austria known for its well preserved upper paleolithic context at a depth of 5 5 m formed between 40 and 20 ka bp by quasi continuous dust sedimentation interrupted by phases of incipient pedogenesis and local reworking the new kw2015 composite is based on three sections studied and sampled at 2 5 cm resolution color and grain size data support a robust stratigraphy for reconstructions of the pedosedimentary evolution the marked transition from oxidized to reduced paleosols of kw2015 around 34 35 ka corresponds to the middle to upper pleniglacial transition as part of a general cooling trend from marine isotope stage mis 3 to 2 intensely modulated by millennial scale climatic fluctuations as recorded in the greenland ice core data the distinct response of kw2015 to these trends highlights that reconstructing lps evolution based on a robust stratigraphy is a prerequisite to paleoenvironmental proxy interpretation

austrian mis 3 2 loess palaeosol records key sites along a west east transect based on a w e transect through the northern loess regions of austria palaeoenvironmental studies were carried out in three loess palaeosol sequences gunderding krems wachtberg and stillfried b locus typicus to complement available results in the context of a multi methodological approach on the base of previously published datings our study concentrates on the mis 3 2 transition the results of detailed micromorphological investigations prove that palaeopedogenesis frost processes and sedimentation rates differ in their spatial occurrence in the loess belt of austria all three sequences are in line with the general trend of a reduced intensity of pedogenic and cryogenic features from western to south eastern europe which can be explained by lower atlantic moisture influence towards the east interstadial cambic horizons are well developed in the mis 3 sequence of western austria whereas the eastern loess profiles only show weak pedogenesis in all studied sequences frost processes were active during the upper mis 3 and mis 2 the studied mis 2 records are characterised by tundra soils with reductaquic horizons which is a clear sign for prolonged phases of permafrost on the spatial scale the sedimentation rate increases in the eastern loess regions and particularly the krems wachtberg sequence in the centre of the transect experienced an exceptionally high sedimentation rate and can thus be seen as one of the most important high resolution records for the mis 3 2 transition in european loess regions

mammoths inside the alps during the last glacial period radiocarbon constraints from austria and palaeoenvironmental implications abstract this study examines remains of the woolly mammoth mammuthus primigenius found inside the austrian alps an area occupied by an extensive ice stream network during the last glacial maximum the data demonstrate that these cold steppe adapted animals locally migrated several tens of kilometers into alpine valleys radiocarbon analyses constrain the age of these fossils to the first half of marine isotope stage 3 documenting ice free conditions in major valleys at that time we also provide a list of all traceable austrian sites of mammuthus primigenius totaling about 230 localities compiled through 15 museums and collections in austria the vast majority of these findings are from the corridors of the danube and mur rivers and their tributaries and the adjacent loess covered foreland of the alps areas that were never ice covered during pleistocene glaciations

fluvial dynamics of the žitava river sw slovakia during the last 45 ka bp and their influence on early bronze age human occupation as part of a geoarchaeological project exploring the early bronze age settlement of fidvar this geomorphologic study explores the fluvial dynamics of the itava river in southwestern slovakia casting light for the first time on the regional river s holocene and late pleistocene development in order to reconstruct the itava s fluvial evolution floodplain deposits were investigated by electrical resistivity tomography selected percussion drillings and ams radiocarbon dating in combination these methods provided a detailed view into the river s history as a result of the climatic variations engendered by the last glacial cycle the fluvial style repeatedly changed between a braided and anastomosing system however during long time periods of the middle and upper plenivistulian the river retained an anastomosing or even meandering style in contrast to central european rivers therefore in agreement with other investigations our results suggest different climatic conditions in the northern pannonian basin from 40 to 20 ka bp during the early and middle holocene a dense vegetation cover dry mesic oak forests led to stable geomorphological conditions and a meandering channel resulted in lateral erosion of the floodplain fringes accumulation of alluvial loamy sediments did not start until the neolithic and has been related to anthropogenic landscape changes similar to other naturally favoured areas central europe finally two reconstructed river positions indicate a considerable lateral fluvial erosion of the early bronze age settlement at fidvar consequently the original settlement area already thought to be the largest in the region was once significantly larger

dusty and honeycomb plagioclase indicators of processes in the uchino stratified magma chamber izu peninsula japan abstract two types of melt inclusion bearing plagioclase coexist in the uchino basalt izu peninsula japan 1 dusty plagioclase with an ab rich core mantled by a dusty zone consisting of more an rich plagioclase and fine melt inclusions and 2 honeycomb plagioclase with a central core containing larger melt inclusions the dusty plagioclase probably forms through partial dissolution of ab rich plagioclase as dusty zones truncate the concentric zonal structure of the ab rich inner core the honeycomb plagioclase is formed by skeletal growth under supercooling conditions this is indicated by the euhedral geometry of the boundary between the inner inclusion free and the outer inclusion bearing zones of the honeycomb plagioclase which has a concentric inner core bimodal distribution of the chemical compositions of phenocryst cores and assemblages in crystal clots suggest that hybridization of basaltic and andesitic magmas took place before crystallization of phenocryst rims the core rim boundaries of phenocrysts derived from the andesitic magma and the basaltic magma have a rounded and a euhedral geometry respectively this suggests the andesitic magma was heated and the basaltic magma was cooled prior to hybridization these features are consistent with the development of a thermal diffusive interface between overlying andesitic magma and underlying basaltic magma in a stratified magma chamber

loess magnetic fabric of the krems wachtberg archaeological site the loess sediment embedding the main gravettian layer at the krems wachtberg archaeological site facilitates exceptional preservation to gain insight in the sedimentation process before and after the palaeolithic settlement the magnetic fabric preferential orientation of magnetic particles of loess of the krems wachtberg site was investigated magnetic fabric properties clearly show an eolian origin of the loess but may indicate some relocation in the metre above the cultural layer the magnetic fabric properties can be divided into three intervals the top interval shows lowest foliation and inconsistent magnetic fabric directions the middle interval around the main cultural layer shows low foliation but a clear preferential nw se direction of the lineation this lineation is interpreted as preferential direction of the eolian loess accumulation from the southeast the interval below 0 5 m underneath the main find horizon shows a northeast southwest lineation but an imbrication suggesting that sediment accumulation occurred at 90 to this direction similar to the interval around the find horizon

modeling elastic properties in carbonate rocks carbonate limestone and dolomite reservoirs account for approximately 50 of oil and gas production worldwide however seismic responses in carbonate rocks are poorly understood in addition dhi ranking and avo classification systems developed for clastic rocks are unlikely to be applicable to carbonate rocks an accurate and physically sound carbonate rock physics model is needed to address these technical issues

a new velocity model for clay sand mixtu res1 none of the standard porosity velocity models e g the time average equation raymer s equations is satisfactory for interpreting well logging data over a broad depth range clays in the section are the usual source of the difficulty through the bias and scatter that they introduce into the relationship between porosity and p wave transit time because clays are composed of fine sheet like particles they normally form pores with much smaller aspect ratios than those associated with sand grains this difference in pore geometry provides the key to obtaining more consistent resistivity and sonic log interpretations a velocity model for clay sand mixtures has been developed in terms of the kuster and toksoz effective medium and gassmann theories in this model the total pore space is assumed to consist of two parts 1 pores associated with sand grains and 2 pores associated with clays including bound water the essential feature of the model is the assumption that the geometry of pores associated with sand grains is significantly different from that associated with clays because of this porosity in shales affects elastic compliance differently from porosity in sand stones the predictive power of the model is demonstrated by the agreement between its predictions and laboratory measurements and by its ability to predict sonic logs from other logs over large depth intervals where formations vary from unconsolidated to consolidated sandstones and shales

middle to late pleistocene multi proxy record of environmental response to climate change from the vienna basin central europe austria abstract tectonic basins can represent valuable archives of the environmental history presented here are the stratigraphy and multi proxy analyses of two adjacent alluvial fans in the quaternary active parts of the vienna basin situated at the interface of the atlantic european continental and mediterranean climate deposits comprise a sequence of coarse grained fluvial deposits intercalated by laterally extensive horizons of pedogenically altered fine sediments to establish palaeoenvironmental reconstructions fine grained sequences from a drill core and outcrop data were analysed according to its malacofauna palaeopedology susceptibility and sedimentology the chronological framework is provided by 38 luminescence ages and supported by geomagnetic polarity investigations distinct warm periods each associated with a geomagnetic excursion are recorded in three pedocomplexes formed during the last interglacial and two earlier interglacial periods indicted to correlate with marine isotope stage mis 9 and mis 11 respectively environmental conditions during the early last glacial period mis 5 c 100 70 ka are reconstructed from mollusc shell rich overbank fines deposited along a former channel belt covered by massive sheetflood deposits during mis 2 analysed warm phases suggest strong variations in humidity ranging from steppe to forest dominated environments the study presents one of the few numerically dated middle pleistocene multi proxy records and one of the most comprehensive malacological datasets covering the early phases of last glacial period of continental europe

modulus decomposition of compressional and shear velocities in sand bodies the advent of borehole shear slowness measurements in sonically slow formations has lead to breakthroughs in the subsurface profiling of geological bodies in sand bodies compressional and shear velocities depend predictably on porosity mineralogy grain contacts and fluid saturation an interpretation is best performed by decomposing the velocities into moduli that are intrinsic measures of the rock frame and pore fluid compressibilities careful experiments on pure materials i e pure quartz sandstones demonstrate two simplifying constitutive relationships first the bulk and shear frame moduli are simple functions of the porosity a comparison of the measured shear frame modulus to the prediction for the pure material distinguishes sand from shale second the ratio of the bulk and shear frame moduli is a constant 0 9 independent of the porosity the measured velocities are directly inverted to yield the bulk modulus of the pore fluid the fluid saturation effects are so dramatic at high porosit

optically stimulated luminescence dating of a danish eemian coastal marine deposit a test of accuracy abstract it is difficult to test convincingly luminescence dating techniques beyond the range of 14c and yet this is essential if claims that optically stimulated luminescence dating using quartz can reach back to beyond 105 years are to be given credence one possible approach is to use coastal marine sand identified as eemian by an examination of the palaeoecology the eemian period in northern europe is considered to last from 132 to 116 ka marine samples are likely to be linked most closely to at least part of this period and modern coastal sands are known to be well bleached thus from a luminescence dating perspective eemian marine sand can be considered to be of known age and it is very likely to be well bleached we have examined such a known age deposit on the east coast of jutland consisting of about 10 m of fine sand grading up from silty clays and clays in the lower part of the section this material is confidently expected to have been deposited during the very late saalian and early mid eemian 133 125 ka we report on the ages of 25 samples associated with this profile the observed overall precision is compared with the calculated precision on individual ages and the mean value of all the ages is compared with the expected mean of 130 ka

the mis 3 2 transition in a new loess profile at krems wachtberg east a multi methodological approach abstract local to regional paleoenvironmental reactions to past climate changes are preserved in loess paleosol sequences lps in order to extract this information we used a multi methodological approach in the upper paleolithic site of krems wachtberg east in lower austria detailed field studies and high resolution geochemical colorimetric and granulometric analyses help to understand the interplay between soil formation loess accumulation and surface processes in comparison to the main profile excavation of krems wachtberg 2005 2015 it can be stated that osl and 14c ages as well as the archeological stratigraphy of both profiles are comparable however pedogenic features are more evident at krems wachtberg east the new investigations show that well established weathering indices do not clearly trace interstadial soil formation in the studied profile apart from this fact single specific elements like fe and mg react more sensitive to initial pedogenic processes weak pedogenesis can further be evidenced by quantitative spectrophotometric results the latter is also capable of refining and supporting the stratigraphy pedology based on field analyses as a general rule next to loess also initial soil horizons of the mis 3 are remarkably rich in primary carbonates indicating that soil formation took place in an alkaline environment due to the fact that hydrolysis of feldspars could not clearly be detected by the application of pedochemical indices soil formation was probably limited to the oxidation of iron bearing minerals and weak carbonate leaching these phases of favorable climatic conditions in terms of pedogenesis were terminated by increasing dust input towards the onset of mis 2 the eolian deposits are overprinted during reducing conditions in soils and or modified by colluvial processes altogether weak pedogenesis can be reliably detected using a multi methodological approach which leads to enhanced paleoenvironmental interpretations the osl ages put the profile in a range of 41 to 30 ka we present a tentative correlation of the studied loess profile to the record of the north greenland ice core project ngrip for the part of the profile where osl and 14c complement each other

osl chronologies of paleoenvironmental dynamics recorded by loess paleosol sequences from europe case studies from the rhine meuse area and the neckar basin abstract loess paleosol sequences lps represent an important terrestrial archive for the reconstruction of the paleoenvironmental evolution during the last glacial cycle in europe in the rhine meuse area and the southwestern germany there are only few numerical ages determined with state of the art luminescence methods which limits the robustness of established chronostratigraphies this study presents a comparative dating approach using quartz and feldspar post infrared pirir 290 optically stimulated luminescence osl from fine and medium grained samples of five loess paleosol sequences paleoenvironmental dynamics are reconstructed by high resolution grain size analysis the osl ages are evaluated as being robust and consistent with other records furthermore we show that ages for hillslope deposits are sometimes overestimated due to low frequency high magnitude erosive processes the integration of osl ages stratigraphy and high resolution grain size data contributes to a temporal more complete data record from western and central europe secondly we propose a combined stratigraphic model for lps of the last glacial cycle which is developed and discussed in the context of other key sites such as havrincourt schwalbenberg ii tonchesberg nussloch and dolni v stonice comparable chronologies and patterns in proxy data between sites with a large spatial distance suggest a possible semi synchronous response to climatic changes in europe by combining our data with the eifel laminated sediment archive elsa and the ngrip ice core a relationship of loess archives and large scale climatic signals is discussed and a proxydata based event stratigraphy is developed this model refines existing chronostratigraphic models and contributes to solve open discussion concerning the timing and demarcation of sedimentary units and sequences from for western and central europe

presence of cave bears in western austria before the onset of the last glacial maximum new radiocarbon dates and palaeoclimatic considerations tischoferhohle and pendling barenhohle near kufstein tyrol are among the only locations where remains of cave bear ursus spelaeus group were found in the western part of austria one sample from each site was radiocarbon dated four decades ago to ca 28 14c ka bp here we report that attempts to date additional samples from pendling barenhohle have failed due to the lack of collagen casting doubts on the validity of the original measurement we also unsuccessfully tried to date flowstone clasts embedded in the bone bearing sediment to provide maximum constraints on the age of this sediment ten cave bear bones from tischoferhohle showing good collagen preservation were radiocarbon dated to 31 1 39 9 14c ka bp again pointing towards an age underestimation by the original radiocarbon dated sample from this site these new dates from tischoferhohle are therefore currently the only reliable cave bear dates in western austria and constrain the interval of cave occupation to 44 3 33 5 cal ka bp we re calibrate and re evaluate dates of alpine cave bear samples in the context of available palaeoclimate information from the greater alpine region covering the transition into the last glacial maximum eventually leading to the demise of this megafauna

paleoenvironmental fluctuations as recorded in the loess paleosol sequence of the upper paleolithic site krems wachtberg abstract the loess paleosol sequence of krems wachtberg is famous for its archeological findings above all its gravettian infant burials it represents a complex system of paleoclimatic fluctuations which is nearly complete and thus enables the correlation with global paleoclimatic records this sequence comprises activity phases with dominant eolian and partly erosional processes as well as stable short periods of weak pedogenesis periglacial environment with drier climate conditions and high eolian sedimentation rates characterize the upper part of the sequence and in periods with lower sedimentation rates cryosols and permafrost induced structures are developed although the krems wachtberg site is situated at a slope position intensive erosional phases events can be excluded the basal parts of the sequence show signs of decalcification bioturbation organic inclusions as well as changes in element distribution pedogenic horizons are partly overprinted by permafrost related structures and are disturbed by redepositional processes to a minor degree remarkably the archeological horizon is not affected by permafrost in contrast to the layers below and above the focus of this study is deciphering stratigraphy by a combination of paleopedological sedimentological analyses with rock magnetic analyses on the chronological scale the sequence records a timespan from 35 ka to 20 ka altogether there is evidence of five pedogenic units and one archeological layer which are correlated with the greenland interstadials gi 7 to gi 2 however an equivalent of a mis 3 interstadial soil comparable with the lohne soil or stillfried b soil could not be detected

our oldest children age constraints for the krems wachtberg site obtained from various thermoluminescence dating approaches abstract we present several approaches to directly date the prehistoric human activity of lighting a fire at the early gravettian infant burial site of krems wachtberg austria by thermoluminescence tl methods blue thermoluminescence b tl from polymineral fine grain and orange red thermoluminescence r tl from fine grained quartz separates both extracted from the baked loess immediately underlying the hearth were employed the b tl dating followed the classic multiple aliquot additive dose maad protocol for r tl dating the multiple aliquot regenerative mar and a shortened single aliquot regeneration sar protocol were tested all thermoluminescence ages obtained agree within 1 uncertainties and assign a weighted mean age of 33 9 2 3 ka to the last use of the hearth and by inference to the infant burial anomalous fading is precluded due to the agreement of results from all luminescence protocols as well as with independent dating methods the tl ages are consistent with calibrated radiocarbon ages on associated charcoal osl dating of the sediment deposition and with age estimates obtained by two magnetic dating approaches

upper palaeolithic occupation in the wachtberg area of krems the evidence of surveys sections and core samples abstract the classic upper palaeolithic location of the wachtberg in krems eastern austria features a multitude of exposures in a limited area of about 50 000 m 2 in addition to gravettian sites which have been investigated in detail in the course of recent years using modern methods there are the records of old excavations several documented sections as well as a considerable number of core samples displaying heterogeneous documentation standards this paper provides an overview of these different sources of information and aims at synthesizing the data for a comprehensive understanding of the local loess sedimentation and palaeolithic occupation

loess deposits and the conservation of the archaeological record the krems wachtberg example recent archaeological excavations at the upper palaeolithic open air site of krems wachtberg in eastern austria exposed a late pleistocene loess sequence an interdisciplinary sampling strategy was applied to the 8 m high north profile the extraordinary conservation of a gravettian living floor with several complex features is discussed in this paper

crystal size distribution csd in rocks and the kinetics and dynamics of crystallization ii makaopuhi lava lake crystal size distribution csd theory has been applied to drill core samples from makaopuhi lava lake kilauea volcano hawaii plagioclase and fe ti oxide size distribution spectra were measured and population densities n were calculated and analyzed using a steady state crystal population balance equation n n0 exp l g slopes on ln n versus crystal size l plots determine the parameter g a product of average crystal growth rate g and average crystal growth time the intercept is j g where j is nucleation rate known temperature depth distributions for the lava lake provide an estimate of effective growth time allowing nucleation and growth rates to be determined that are independent of any kinetic model plagioclase growth rates decrease with increasing crystallinity 9 9 5 4 10 11 cm s as do plagioclase nucleation rates 33 9 1 6 10 3 cm3 s ilmenite growth and nucleation rates also decrease with increasing crystallinity 4 9 3 4 10 10 cm s and 15 2 2 10 3 cm3 s respectively magnetite growth and nucleation rates are also estimated from the one sample collected below the magnetite liquidus g 2 9 10 10 cm s j 7 6 10 2 cm3 s moments of the population density function were used to examine the change in crystallization rates with time preliminary results suggest that total crystal volume increases approximately linearly with time after 50 crystallization a more complete set of samples is needed for material with 50 crystals to define the entire crystallization history comparisons of calculated crystallization rates with experimental data suggests that crystallization in the lava lake occurred at very small values of undercooling this interpretation is consistent with proposed thermal models of magmatic cooling where heat loss is balanced by latent heat production to maintain equilibrium cooling

loess chronology of the last interglacial glacial cycle in bohemia and moravia czech republic abstract combined infrared and green light stimulated luminescence and thermoluminescence dating applied to the extensively studied bohemian and moravian loess palaeosol sequences from sedlec suchdol kutna hora dolni v stonice lechovice mod ice bulhary and cerven kopec provides a reliable chronological framework for the last interglacial glacial cycle based on this luminescence dating study a new chronology is proposed for the last interglacial glacial loess palaeosol sequences from the czech republic irsl and tl dating suggests that the bt horizon of a truncated brown forest soil lower pk iii formed during the last interglacial equivalent to oxygen isotope substage 5e the upper chernozem of pkii belongs to oxygen isotope stage 3 if the combined irsl and tl age estimates are taken into account although from geological estimates an age range within oi substage 5a is most likely the upper weichselian loess accumulated at a very high rate owing to the high accumulation rate there is no time difference in sedimentation ages between the tundra gley palaeosols above pk i which include the upper weichselian sediments in central europe

chronostratigraphy of two late pleistocene loess palaeosol sequences in the rhone valley southeast france abstract a sedimentological and chronostratigraphical investigation was carried out on two loess sections located in the mediterranean area in southeast france along the rhone river lautagne and the lower reach of a tributary of the rhone river collias high resolution sampling 5 20 cm for magnetic susceptibility grain size distribution including non parametric end member modelling colour reflectance and geochemistry was performed the chronology was based on luminescence dating of quartz grains and radiocarbon dating of small gastropod shells coupled with hierarchical bayesian modelling the collias section 8 m thick records the whole last climatic cycle it comprises a thick red basal pedocomplex s1 developed during the last interglacial and the early glacial similar to that observed elsewhere in southern and southeastern europe loess deposition occurred during the lower l1l2 and the upper pleniglacial l1l1 it was interrupted by soil formation during the middle pleniglacial of which a brown bwk horizon has been preserved l1s1 by contrast the 5 m thick lautagne section provides a detailed record of the upper pleniglacial weakly developed hydromorphic soils are correlated with the greenland interstadials gi 4 to gi 2 while the main period of coarse loess sedimentation corresponds to the greenland stadials gs 5 to gs 2 at a regional scale the time of loess deposition ranges between 38 5 ka and 12 ka with a peak at 28 24 ka overlapping with the maximal advance of the alpine ice sheet ais this strongly suggests that regional glacier dynamics was the main driver of loess sedimentation

rock physics estimation of cement volume sorting and net to gross in north sea sandstones rock physics represents the link between geologic reservoir parameters e g porosity clay content sorting lithology saturation and seismic properties e g vp vs density elastic moduli rock physics models can either be used to interpret observed sonic and seismic velocities in terms of reservoir parameters or they can be used to extrapolate beyond observed range to predict certain what if scenarios in terms of fluid or lithology substitution rock physics models can also be used to estimate expected seismic properties from observed reservoir properties

thermoluminescence dating of loess deposits at paudorf austria abstract the fine grain thermoluminescence tl dating method was applied to an upper palaeosol from a loess deposit in paudorf lower austria this site is of special interest as there is some controversy about the time of formation of this soil horizon the results of the present study strongly indicate that the soil formed during the wurm i ii interstadial deep sea 18 o isotope stage 3 although age underestimation due to a long term instability of luminescence centres in general cannot be ruled out arguments are given for the presented tl age which is also corroborated by the radiocarbon age of charcoal from the top part of the correlated palaeosol in aigen lower austria

high resolution record of the last interglacial glacial cycle in the nussloch loess palaeosol sequences upper rhine area germany the nussloch loess sequences were sampled at close intervals 10 cm and documented in respect of their stratigraphy palaeopedology sedimentology palynology malacology and geochemistry and were dated using radiocarbon and osl methods for each stratigraphic unit the results of both the eld studies and the analytical and geochronological data obtained cast light upon the response of the loessic environment to global climatic variations during the last cycle the basal soil complex underwent a pedosedimentary evolution similar to those of the bordering area complex luvisol greyzem steppe soila which re ects the classic progression towards increased continentality of the environment between the end of the eemian 5d and the beginning of the full glacial stage pleniglacial the lower pleniglacial corresponds to an initially very arid phase dominated by the accumulation of loess followed by the deposition of strati ed niveo eolian sands the middle pleniglacial complex ca 55 30 is clearly characterised by the inhibited loessic sedimentation it is primarily marked by two phases of stabilisation recorded in the form of weathered horizons cambisols which are separated by a rather thin layer corresponding to loessic sedimentation with tundra gleys this intermediate phase brings together organic silt deposits which record an interstadial dated at 32 33 ka c bp the thick loessic accumulations of the upper pleniglacial 10 m which clearly began to accumulate before the oxygen isotope stage ois 3 2 boundary show evidence of vulnerability to considerable uctuations in response to variations in wind dynamics and the intensity of de ation in the rhine valley finally a proposed correlation of loess palaeosol stratigraphies from germany belgium and france spanning the entire last interglacial glacial cycle is presented 2001 elsevier science ltd and inqua all rights reserved

luminescence based loess chronostratigraphy of the upper palaeolithic site krems wachtberg austria abstract the loess section krems wachtberg lower austria is well known for its upper palaeolithic find layer which contains a double and a single infant burial the layer containing the grave archaeological horizon ah 4 4 was dated to 26 580 160 14 c bp einwogerer et al 2006 corresponding to ca 31 ka cal bp and is embedded in an 8 m thick loess sequence in order to provide a chronostratigraphy of the entire section 38 samples for luminescence dating were taken at high resolution from below and above the find layer the samples were dated using the quartz coarse grain fraction the quartz fine grain fraction and or the polymineral fine grain fraction the resulting ages are in correct chronostratigraphic order and in case samples were measured with different protocols agree within errors with each other and with the radiocarbon age of the find layer the polymineral fine grain ages are systematically slightly lower than the quartz ages although no fading could be detected in laboratory experiments loess deposition at the site commenced ca 40 ka ago and reaches up to ca 22 ka the ages indicate nearly continuous loess sedimentation throughout this time span short breaks in sedimentation probably exist but cannot be resolved due to the uncertainties of luminescence ages

high resolution osl dating of the costinesti section dobrogea se romania using fine and coarse quartz abstract previous studies on the application of optically stimulated luminescence dating on quartz extracted from romanian loess yielded inconsistent age estimates between different grain sizes the present work reports a high resolution sar osl chronology for the l1 mis 2 4 s1 mis 5 and l2 mis 6 units of the loess palaeosol profile from costinesti that contains at least five loess palaeosol alternations and is located on the black sea shore dobrogea se romania analysis were performed on fine 4 11 m and coarse 63 90 m quartz grains extracted from 25 samples collected at very high resolution 10 20 cm luminescence investigations confirm the reliability of the sar osl dating protocol previously applied to romanian loess preheat at 220 c for 10 s cutheat to 180 c and elevated temperature osl etosl the dose response curve is best described by the sum of two saturating exponential functions the results confirm the different saturation characteristics of fine and coarse grains of quartz as reported in previous studies on loess sections in se romania the equivalent doses obtained for coarse grains are higher than those obtained for fine grains for all samples the fine quartz osl age estimates are significantly younger than the coarse quartz age results as in the case of previous studies on the mircea vod and mostistea loess sections coarse quartz in samples collected from the upper part of s1 yielded ages of 94 11 ka 116 11 ka and 120 10 ka that do not seem to underestimate the true burial age the same observation applies to the upper part of l2 overall from the luminescence results it can be concluded that the s1 palaeosol formed during the mis 5 and the discrepancy observed on coarse and fine quartz osl ages is a general feature of se romanian loess

the eltville tephra western europe age revised integrating stratigraphic and dating information from different last glacial loess localities abstract the eltville tephra et is an important stratigraphic marker bed in the western european loess stratigraphy at the boundary between the regional last glacial maximum lgm in the sense of the maximum extent of glaciation of the scandinavian ice sheet and a terrestrial lgm with the highest degree of aridity and coldness stratigraphic marker beds such as tephra layers are commonly dated at more than one location and often with more than one method the sediments surrounding the et were dated 87 times at 15 localities with different luminescence techniques yielding ages between 13 5 and 49 6 ka based on individual sections the deposition of the et was supposed to have taken place between 20 and 23 ka this raises the question of whether a quantitative combination of individual ages can give a reproducible common age including uncertainties after screening the dataset and applying selection criteria a bayesian resampling approach is applied to obtain a common age consistent with a high percentage of observations from multiple localities four new luminescence ages bracketing the et and two ages directly generated from the tephra horizon are presented and combined with all available data the 1 age range of the bayesian age modelling yields a deposition age between 23 2 and 25 6 ka which is in excellent agreement with two new luminescence ages from the tephra of 24 1 1 9 ka quartz and 24 3 1 8 ka pirir290 and a peak of volcanic minerals in the dehner maar core around 24 3 ka this age is clearly older than previously suggested for the et volcanic eruption but fits better with stratigraphic and paleoenvironmental evidence therefore the et was deposited during phases of strong aeolian activity of the greenland stadial 3 additionally for the first time a correlation can be made between the et and tephra layers recognized in the eifel maar lake cores

a new approach to petroelastic modeling of carbonate rocks using an extended pore space stiffness method with application to a carbonate reservoir in central luconia sarawak malaysia

environmental dynamics and luminescence chronology from the orlovat loess palaeosol sequence vojvodina northern serbia the carpathian basin contains some of the best preserved loess deposits in europe including some of the continent s longest and best resolved climate records large areas of the basin have been intensively investigated in recent years although deposits in the east remain largely unstudied despite considerable regional variation in climate records here we discuss the sedimentary record exposed in the orlovat brickyard using detailed litho and pedo stratigraphic enviromagnetic parameters and luminescence dating the results show an atypical late pleistocene succession for the carpathian basin notably the normally widespread pedocomplex v l1s1 is missing this contrasts with other parts of the sequence which appear highly resolved such as the thicker pedocomplex v s1 and the detailed transitions between modern pedocomplexes v s0 and the last glacial loess unit v l1 the luminescence chronology demonstrates a lack of intensive pedogenesis during the early holocene and raises an important general question about the beginning of holocene soil formation in the region the later holocene soil formation adds to a growing body of evidence that suggests more complex terrestrial responses of climate to global climate change this evidence weakens the validity of previously generalized direct stratigraphic correlations between regional terrestrial environmental archives and global marine and ice core records copyright 2014 john wiley sons ltd

combined irsl and post ir osl dating of romanian loess using single aliquots of polymineral fine grains abstract the paper reports on continuing luminescence investigations of romanian loess using samples collected from the loess palaeosol sequence near mircea vod se romania previous optically stimulated luminescence osl studies using different grain sizes of quartz 4 11 m and 63 90 m yielded discrepant chronologies for the last interglacial glacial cycle in this study a double sar protocol is used to determine the age of polymineral fine 4 11 m grains through their infrared stimulated luminescence irsl and post ir optically stimulated luminescence post ir osl emissions in the uv laboratory tests confirm the suitability of the protocol for both signals fading measurements indicate a significant feldspathic contribution to the post ir osl signal in general the fading corrected irsl and post ir osl age results are mutually consistent and they agree with previously reported osl ages for fine grained 4 11 m quartz this agreement enhances the reliability of the ages obtained using luminescence signals from fine grains and allows more confident correlation of the weakly developed palaeosol in the uppermost loess unit l1 with marine isotope stage 3 mis3 the fading corrected ages underestimate the depositional age of older material units l2 l4 probably owing to limitations of the correction model

the greenland ice core chronology 2005 15 42 ka part 1 constructing the time scale the greenland ice core chronology 2005 gicc05 is extended back to 42 ka b2k before 2000 ad i e to the end of greenland stadial 11 the chronology is based on independent multi parameter counting of annual layers using comprehensive high resolution measurements available from the north greenland ice core project ngrip these are measurements of visual stratigraphy conductivity of the solid ice electrolytical melt water conductivity and the concentration of na c a 2 s o 4 n o 3 n h 4 a n uncertainty estimate of the time scale is obtained from identification of uncertain annual layers which are counted as 0 570 5 years the sum of the uncertain annual layers the so called maximum counting error of the presented chronology ranges from 4 in the warm interstadial periods to 7 in the cold stadials the annual accumulation rates of the stadials and interstadials are on average one third and half of the present day values respectively and the onset of the greenland interstadials 2 3 and 8 based on 20 year averaged d 18 o

steady state volcanism paleoeffusion rates and magma system volume inferred from plagioclase crystal size distributions in mafic lavas dome mountain nevada abstract the dome mountain dm lavas located in the moat of the timber mountain caldera of the sw nevada volcanic field cap a thick sequence of welded tuffs massive and bedded tuffs and mafic and rhyolitic lava flows these 10 9 m y old flows comprise a pile of some twenty flows with a total thickness of about 300 m individual flows range in thickness from 3 to 20 m and are characterized by a basal vesicular zone a massive central region and an upper vesicular region containing in most cases cooling fractures the flows dip gently away from the summit of dm a prominent topographic feature of the region with an elevation of 2065 m silica contents range from 48 8 wt at the base of the pile to 59 4 wt at the top although most of the flows are andesitic crystal size distributions csds for plagioclase in these comagmatic lavas have been determined to provide information on magma storage times these times when coupled with phase equilibria can be used to infer cooling rates which are indicative of the relative dimensions of magmatic bodies and the vigor of various magmatic cooling processes most of the csds show no sign of crystal fractionation or accumulation assuming a growth rate of 10 10 cm s calculated mean crystal residence times for most lavas cluster in the range of 1 5 to 4 years two of the lower lavas have residence times in the range of 4 to 9 years the residence times correlate inversely with nucleation density and broadly correlate inversely with silica content high residence time low silica lavas occur at the base of the pile whereas low residence time high silica lavas occur at the top of the pile one interpretation of the residence time data is that the lavas are from an open system of more or less constant residence time but varying spatially in system locations e g a magma chamber in which steady state recharge and eruption may have been reached alternatively these lavas may represent small samples closely spaced in time of a slowly cooling large batch or reservoir of magma the greater residence times associated with the lower flows may indicate the increased amount of time necessary to form the conduit of the magma volcano system by the oldest magma or simply that part of the system with the highest liquidus temperature a minimum volume of 1 4 to 2 5 km 3 for the magma chamber is estimated for the dm system using the estimated residence times in a simplified cooling model of a sheet of aspect ratio r the actual system volume depends on r which is strictly unknown and thus the actual system volume may be much larger e g 200 km 3 a mean paleoeffusion rate of 0 05 km 3 yr is obtained for the lavas by assuming that the residence time of each lava corresponds to the amount of time elapsed since the eruption of the underlying flow

european middle pleistocene loess chronostratigraphy some considerations based on evidence from the wels site austria a combination of site logging luminescence dating and comparison with different long and continuous records of past environmental conditions is used to elaborate an age model for the wels loess palaeosol site austria according to this model marine isotope stage mis 7 is reflected in the development of three red forest soils luvisols at this particular site this is contrary to previous assumptions that suggested the development of such soils in the region at 100 ka cyclicity if these results are correct this may question some previous conclusions regarding the general loess stratigraphy in many parts of europe

environments at the mis 3 2 transition in the northern alps and their foreland abstract this paper reviews the current state of knowledge about environmental changes at the mis 3 2 transition in the northern alps and their foreland covering the time frame from 35 to 25 ka lake and peat deposits cave sediments loess and glacial deposits are presented and the response of their biotic and abiotic proxies to climate change is discussed during late mis 3 interstadial conditions albeit weak occurred at c 36 32 ka at climatically favourable sites small patches of trees mainly pinus and some betula existed together with some shrubs the environmental conditions during late mis 3 are also reflected by a boreal brown soil horizon a cambisol called lohne soil found in many loess sequences subsequently the environmental conditions became harsher as shown by the proxy data from c 30 ka onwards the absence of pedogenesis sensu stricto and the plant assemblages point to an arctic climate in the northern alpine foreland accentuating glaciers advanced beyond the northern limit of the alps around the mis 3 2 boundary and reached their maximum extent in the foreland at about 25 ka

geophysical evidence for the locations shapes and sizes and internal structures of magma chambers beneath regions of quaternary volcanism this paper is a review of seismic gravity magnetic and electromagnetic techniques to detect and delineate magma chambers of a few cubic kilometres to several thousand cubic kilometres volume a dramatic decrease in density and seismic velocity and an increase in seismic attenuation and electrical conductivity occurs at the onset of partial melting in rocks the geophysical techniques are based on detecting these differences in physical properties between solid and partially molten rock although seismic refraction techniques with sophisticated instrumentation and analytical procedures are routinely used for detailed studies of crustal structure in volcanic regions their application for magma detection has been quite limited in one study in yellowstone national park u s a fan shooting and time term techniques have been used to detect an upper crustal magma chamber attenuation and velocity changes in seismic waves from explosions and earthquakes diffracted around magma chambers are observed near some volcanoes in kamchatka strong attenuation of shear waves from regional earthquakes interpreted as a diffraction effect has been used to model magma chambers in alaska kamchatka iceland and new zealand one of the most powerful techniques in modern seismology the seismic reflection technique with vibrators was used to confirm the existence of a strong reflector in the crust near socorro new mexico in the rio grande rift this reflector discovered earlier from data from local earthquakes is interpreted as a sill like magma body in the kilauea volcano hawaii mapping seismicity patterns in the upper crust has enabled the modelling of the complex magma conduits in the crust and upper mantle on the other hand in the usu volcano japan the magma conduits are delineated by zones of seismic quiescence three dimensional modelling of laterally varying structures using teleseismic residuals is proving to be a very promising technique for detecting and delineating magma chambers with minimum horizontal and vertical dimensions of about 6 km this technique has been used successfully to detect low velocity anomalies interpreted as magma bodies in the volume range 10 3 10 6 km 3 in several volcanic centres in the u s a and in mt etna sicily velocity models developed using teleseismic residuals of the cascades volcanoes of oregon and california and kilauea volcano hawaii do not show appreciable storage of magma in the crust however regional models imply that large volumes of parental magma may be present in the upper mantle of these regions in some volcanic centres teleseismic delays are accompanied by p wave attenuation and linear inversion of spectral data have enabled computation of three dimensional q models for these areas the use of gravity data for magma chamber studies is illustrated by a study in the geysers clear lake volcanic field in california where a strong gravity low has been modelled as a low density body in the upper crust this body is approximately in the same location as the low velocity body delineated with teleseismic delays and is interpreted as a magma body in yellowstone national park magnetic field data have been used to map the depth to the curie isotherm and the results show that high temperatures may be present at shallow depths beneath the yellowstone caldera the main application of electrical techniques in magma related studies has been to understand the deep structure of continental rifts electromagnetic studies in several rift zones of the world provide constraints on the thermal structure and magma storage beneath these regions