european glacial dust deposits geochemical constraints on atmospheric dust cycle modeling for a long time global paleodust numerical simulations have greatly underestimated dust sources other than modern deserts recent modeling experiments incorporating glaciogenic sources of dust have positively improved the agreement between model and paleodust data this highlights the importance of accurately representing all areas potentially subjected to deflation during an investigated interval geochemical results obtained from european loess sequences collected along a 50 n transect combined with dust emission simulations reveal the geographical distribution of the most important european dust sources between 34 ka and 18 ka we demonstrate that most european dust traveled only a few hundred kilometers or less within the boundary layer from its source before deposition we conclude that our results encourage acquisition of similar geochemical data for other relevant areas in the world further they could provide critical constraints to benchmark atmospheric models contributing to improve their performance in simulating dust cycle and associated climate feedbacks

spatial and temporal distribution of slip for the 1999 chi chi taiwan earthquake we investigated the rupture process of the 1999 chi chi taiwan earth quake using high quality near source strong motion records broadband teleseismic displacement waveforms and well distributed global positioning system gps data the near source strong motion displacement waveforms recorded significant static offsets of up to 8 m the teleseismic displacement records show a significant pulse with duration of about 18 to 20 sec taking into account the surface displacements observed along the chelungpu fault we considered two fault geometries a single planar fault and a two segment fault with a northeast striking section near the north ern end using the finite fault model with variable slip vectors we derived two models of the temporal and spatial slip distribution of the earthquake the gps data provided good surface displacement constraints for the slip distribution determina tion the spatial slip distribution is generally consistent with field observations the results for the simple fault model show a large asperity located in the region about 25 to 55 km north of the hypocenter with maximum slip of about 15 m when we use the two segment model the asperity further extends to the region where the fault bends toward the northeast with a maximum slip of up to 20 m a large amount of right lateral slip beneath station tcu068 is necessary to explain its observed large west movement it implies a local converging slip at the corner where the fault bends to the northeast the slip amplitude near the hypocenter is about 3 to 6 m the seismic moments determined from the various data sets are within the range of 2 to 4 10 27 dyne cm most of the slip concentrated at shallow depths less than 10 km the total rupture duration is about 28 sec and the rupture velocity is 75 to 80 of the shear wave velocity the slip vector shows a clockwise rotation during the fault rupture the static stress drop of the large asperity region is comparable with the dynamic stress drop as observed directly from the slip velocity at the station near the large slip region

upper pleistocene loess palaeosol records from northern france in the european context environmental background and dating of the middle palaeolithic abstract in northern france the loess cover from the last glacial weichselian is represented by a semi continuous mantle up to 8 m in thickness in the best localities such as leeward slopes e ne exposures in this large area pedostratigraphic sequences from the last interglacial glacial cycle eemian weichselian have been intensively studied especially under the auspices of active rescue archaeological programmes that have provided hundreds of individual sequences from test pits or excavations in spite of variations in the thickness of the different stratigraphic units driven by differences in geomorphological contexts the pedostratigraphic sequences from the last interglacial glacial cycle exhibit a particularly constant pedosedimentary pattern including well identified pedological and periglacial marker horizons that can be followed towards the east in belgium in germany and even in central europe according to the newest data it is shown that northern france loess palaeosol sequences are well suited to record the response of western european environments to rapid climatic changes dansgaard oeschger cycles the main objective of this paper is to present a summary of the pedostratigraphic sequence from northern france supplemented by the data from the new reference sequence of havrincourt and a global correlation scheme with surrounding areas in northern france the synthesis of the observations carried out on ca 100 sequences during the last 20 years allows the establishment of a highly detailed pedostratigraphic and chronostratigraphic scheme that represents a unique database for the discussion of the relations between palaeolithic occupation and environment in this context a strong relationship between the intensity of human occupation and the climatic and environmental context is demonstrated this relationship appears to be conditioned by the relative abundance of large mammal fauna itself linked to vegetation density as indicated by the extremely sparse biomass and the hiatus in human occupation that characterise upper pleniglacial loess

magnetic anisotropy reveals the depositional and postdepositional history of a loess paleosol sequence at nussloch germany anisotropy of magnetic susceptibility ams is employed as a tool to unravel the depositional history of the 17 m thick nussloch p8 weichselian loess sequence located 10 km south of heidelberg germany through an ams study the primary aeolian depositional origin of the magnetic fabrics is evaluated and overprinting due to postdepositional reworking and or deformation is identified primary fabrics along the p8 sequence are defined by near vertical kmin axes and horizontal foliations eight intervals display secondary fabrics characterized by either prolate orientation distributions or oblate orientation distributions with dipping foliation planes these postdepositional fabrics are associated with laminated loess and tundra gley horizons it is proposed that increased moisture due to higher precipitation or enhanced snowmelt and repeated cryogenic processes were able to reorganize and rework the accumulated loess primary aeolian fabrics are archived within 6 45 m of cumulated depth or 38 of the profile and dominantly within the upper pleniglacial units even though maximum susceptibility axes of primary fabrics are statistically well resolved at the specimen e12 10 1 8 6 and population e12 6 level any inferred paleowind directions from the magnetic lineation remains speculative given the low concentration of ferrimagnetic minerals 0 03 wt tundra gley horizons upprofile display primary magnetic fabrics and no major changes in the degree of anisotropy or ams orientation distributions this suggests a weakening in gley induced diagenesis and therefore favorable environmental conditions needed moisture and presence of permafrost active layer to initiate their formation in loess deposits finally pedogenesis has not played an important role in modifying the magnetic fabric since paleosols display the same magnetic fabrics observed in primary loess

high resolution record of the environmental response to climatic variations during the last interglacial glacial cycle in central europe the loess palaeosol sequence of dolni věstonice czech republic abstract high resolution multidisciplinary investigation of key european loess palaeosols profiles have demonstrated that loess sequences result from rapid and cyclic aeolian sedimentation which is reflected in variations of loess grain size indexes and correlated with greenland ice core dust records this correlation suggests a global connection between north atlantic and west european air masses herein we present a revised stratigraphy and a continuous high resolution record of grain size magnetic susceptibility and organic carbon 13c of the famous of dolni vestonice dv loess sequence in the moravian region of the czech republic a new set of quartz osl ages provides a reliable and accurate chronology of the sequence s main pedosedimentary events the grain size record shows strongly contrasting variations with numerous abrupt coarse grained events especially in the upper part of the sequence between ca 20 30 ka this time period is also characterised by a progressive coarsening of the loess deposits as already observed in other western european sequences the base of the dv sequence exhibits an exceptionally well preserved soil complex composed of three chernozem soil horizons and 5 aeolian silt layers marker silts this complex is at present the most complete record of environmental variations and dust deposition in the european loess belt for the weichselian early glacial period spanning about 110 to 70 ka allowing correlations with various global palaeoclimatic records osl ages combined with sedimentological and palaeopedological observations lead to the conclusion that this soil complex recorded all of the main climatic events expressed in the north grip record from greenland interstadials gis 25 to 19

characterization of late glacial continental dust in the greenland ice core project ice core twelve glacial dust samples extracted from the greenland ice core project ice core have been characterized in terms of mineralogy sr and nd isotopic composition and rare earth element concentrations the ice samples are taken from the younger dryas the bolling the last glacial maximum and both cold and mild glacial periods back to 44 kyr b p a comparison with samples from possible dust source areas determines eastern asia as being the main source area at all times hereby confirming and extending earlier results biscaye et al 1997 this finding is partly in agreement with recent atmospheric general circulation model simulations of glacial atmospheric dust transport andersen et al 1998 mahowald et al 1999 a low intersample variability in tracer characteristics is discussed in the context of a volcanogenic influence grain size dependence and variability in the conti nental dust source areas the clay mineralogy of the ice core dust shows a weak climatic de pendence while the isotopic composition of sr and nd does not correlate with climate this is interpreted as a geographical variation of source areas on a regional scale within asia two ice dust samples were size fractionated at 2 gm and the grain size dependence on tracer characteristics is in accordance with the literature

the loess and coversands of northern france and southern england loess and coversands are widespread on either side of the english channel in southern england loess is generally thin and discontinuous but locally reaches thickness of about 4 m in east kent coversands occur mainly in areas well north of the channel such as parts of east anglia and the southern side of the bristol channel most of the loess and coversand deposits in southern england date from the late devensian cold stage marine oxygen isotope stage mois 2 but there are also a few localised patches of older mainly mois 6 and 12 loess which are the dissected remnants of originally more extensive covers in france loess is widespread and locally very thick up to 12 m especially in northern and northeastern france in normandy and in the somme basin some long records indicate that accumulation began at the end of the lower pleistocene at about 900 ka nevertheless the main accumulations of typical calcareous loess are related to the upper weichselian and upper saalian stages mois 2 and end of mois 3 and mois 6 indeed before about 160 170 ka loess deposition was generally restricted to special sediment traps such as fluvial and marine terraces exposed to the east or northeast these older deposits are characterised by more sandy facies derived from local fluvial sources mainly by northwest to north northwest winds coversands occur locally along the coast of the mont saint michel bay and over the northern part of the seine estuary near le havre the main differences in thickness and extent of the loess deposits between southern england and northern france are linked to their location in relation to the source areas channel and north sea to ice sheets and to the main wind directions northwest to north northwest in france and western england but northeast in eastern england copyright 2003 john wiley sons ltd

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

dynamics and sources of last glacial aeolian deposition in southwest france derived from dune patterns grain size gradients and geochemistry and reconstruction of efficient wind directions abstract dune pattern grain size gradients and geochemistry were used to investigate the sources and dynamics of aeolian deposition during the last glacial in southwest france the coversands form widespread fields of low amplitude ridges zibars whereas younger dryas parabolic dunes mainly concentrate in corridors and along rivers spatial modelling of grain size gradients combined with geochemical analysis points to a genetic relationship between coversands and loess the latter resulting primarily from dust produced by aeolian abrasion of the coversands the alluvium of the garonne river provided also significant amounts of dust at a more local scale the geochemical composition of loess shows much lower scattering than that of coversands due to stronger homogenisation during transport in the atmosphere overall sandy loess and loess deposits decrease in thickness away from the coversands dune orientation and grain size gradients suggest that the efficient winds blew respectively from the w to the nw during the glacial and the w sw during the younger dryas a comparison between the wind directions derived from the proxy data and those provided by palaeoclimatic simulations suggests a change of the main transport season ground surface conditions and their evolution throughout the year i e the length of the season with snow and frozen or moist topsoil and the seasonal distribution of wind speeds able to cause deflation are thought to have been the main factors that controlled the transport season in the study area

green amphibole distribution as a stratigraphic tool in loess sequences from belgium a review abstract the use of heavy minerals as a stratigraphic tool in the study of loess sequences from nw europe originated some 70 years ago one major problem in using the available data sets is the heterogeneous stratigraphic context of the samples given the complex historic evolution of the stratigraphic framework of loess sequences this paper aims at presenting a review of the use of heavy minerals for stratigraphic studies in loess sequences from belgium focusing on the important role of green amphiboles we provide the first synthesis of the available data for belgium in a common and accurate lithostratigraphic framework i e the loess lithostratigraphic units recently reviewed by the national commission for stratigraphy a total of 121 samples studied by 4 different researchers and collected from 13 different loess sections are considered we also document the detailed mineralogical composition of these green amphiboles based on new microprobe analyses our results show that the green amphibole content of regional loess deposits presents a remarkable consistency in their stratigraphic distribution five groups are defined here covering the entire pleistocene loess sequence from mis 11 to weichselian while ga distribution used alone is not a discriminatory criterion it becomes most of the time discriminatory when combined with the palaeoenvironmental signature of the sequence deduced from pedostratigraphy

loess paleosol sequences at the northern european loess belt in germany distribution geomorphology and stratigraphy abstract pleistocene loess and loess derivates are distributed along the mountain front of the central european mountain belt in northern and central germany examples from two regions the lower rhine embayment lre and the northern foreland of the harz mountains fhm show that the distribution of loess and the development of loess paleosol sequences lps are controlled by relief climate tectonics the distance to large river systems the distance to the scandinavian ice sheet and the distance to the shelf of the north sea in the oceanic lre higher humidity enhanced the periglacial processes which increased erosion but also led to preservation in accumulative positions in contrast in the more continental fhm the sediments were affected by less intensive periglacial processes and no solifluction can be detected new loess distribution maps are presented for both key areas and key sections especially for the last glacial cycle are compared and summarized both study regions are located in the west east trending loess belt north of the central european mountain belt in front of the rhenish shield ardennes eifel and harz mountains finally a synthesis of typical sediment sequences for both regions is given as an example of paleoenvironmental landscape development in northern central europe

genesis and evolution of regoliths evidence from trace and major elements and sr nd pb u isotopes abstract regoliths encompass different materials from the fresh bedrock to the top of the organic horizons the occurrence and evolution of these materials are determined by deposition erosion and weathering processes that are specific for each region the origin and interaction of the regolith layers are still important issues in the study of critical zone functioning studies that attempt to understand the processes responsible for the structure and the evolution of regoliths often focus either on the soil or on the bedrock compartment and often from a narrowly focused approach using just a single tool such as major element patterns or mineralogy this limits the understanding of the complete regolith composition and evolution the present study proposes the combination of mineralogy major and trace element concentrations and sr nd pb u isotopes as an extremely useful procedure for tracking the spatial and temporal origin of regolith materials and understanding their stratification this multi tracer approach was applied on a regolith profile from the south western edge of the rhenish massif which is characterised by the occurrence of slate bedrocks and overlying pleistocene periglacial slope deposits ppsd the data allowed the differentiation of three compartments within the regolith 1 the organic compartment where low 206pb 207pb and 87sr 86sr isotopic ratios reflected the impact of atmosphere derived components 2 the ppsd compartment whose upper horizons were characterised by the presence of atmosphere derived particles rich in cd sn sb hg and pb and by relatively low 206pb 207pb and 87sr 86sr ratios whereas the lower horizons showed nb enrichments in their matrix and a mineralogical composition pointing to ancient volcanic events and 3 the weathered slate compartment whose weathering progression and genetic relationship with the ppsd were particularly well tracked with 87sr 86sr and 143nd 144nd isotope ratios 234u 238u activity ratios and positive ce anomalies the results prove the efficiency of radiogenic isotope measurements combined with the analysis of major and trace elements to complete regolith studies moreover these isotopes and elements are shown to be potential geochemical tracers of exchange processes at the water mineral interface this approach allows for the first time the description of an evolution scheme of a complete slate regolith which covers a large part of the rhenish massif

mis3 2 millennial oscillations in greenland dust and eurasian aeolian records a paleosol perspective abstract since their discovery the abrupt climate changes that punctuated the last glacial period 110 6 14 62 ka have attracted considerable attention originating in the north atlantic area these abrupt changes have been recorded in ice marine and terrestrial records all over the world but especially in the northern hemisphere with various environmental implications ice core records of unprecedented temporal resolution from northern greenland allow to specify the timing of these abrupt changes which are associated with sudden temperature increases in greenland over a few decades very precisely the continental records have so far been mainly interpreted in terms of temperature precipitation or vegetation changes between the relatively warm greenland interstadials gi and the cooler greenland stadials gs here we compare records from greenland ice and northwestern european eolian deposits in order to establish a link between gi and the soil development in european mid latitudes as recorded in loess sequences for the different types of observed paleosols we use the correlation with the greenland records to propose estimates of the maximum time lapses needed to achieve the different degrees of maturation and development to identify these time lapses more precisely we compare two independent ice core records 18 o and dust concentration indicating variations of atmospheric temperature and dustiness in the greenland area respectively our method slightly differs from the definition of a gi event duration applied in other studies where the sharp end of the 18 o decrease alone defines the end of a gi we apply the same methodology to both records i e the gis are defined to last from the beginning of the abrupt 18 o increase or dust concentration decrease until the time when 18 o or dust recur to their initial value before the gi onset determined both visually and algorithmically and compare them to published estimates of gi timing and duration the duration of the gi and consequently the maximum time for paleosol development varies between 200 and 4200 years when visually determined and between 200 and 4800 years when estimated algorithmically for gi 17 to 2 i e an interval running from 60 ka to 23 ka b2k age before 2000 ad furthermore we investigate the abruptness of the transition from stadial to interstadial conditions which initiates the paleosol development the average transition duration is 55 4 16 1 56 8 19 6 years when determined visually and 36 4 13 4 60 00 21 2 years when determined algorithmically for the 18 o dust concentration the 18 o increases correspond to a mean temperature difference of 11 8 c on the top of the greenland ice sheet associated with substantial reorganizations of the ecosystems in mid latitude europe

the upper pleistocene loess record at harmignies belgium high resolution terrestrial archive of climate forcing abstract the loess palaeosol sequence in a section at harmignies in belgium is one of the most important upper pleistocene sites in northwest europe an extensive luminescence dating study was carried out to get a reliable chronological framework and to understand the climate forcing in an area where continuous permafrost dominated during most of the last glaciations twenty eight samples were investigated by infrared optically stimulated luminescence irsl and thermoluminescence tl methods resulting in more than 100 luminescence age estimates the dating results on colluvial sediments are in good agreement with landscape destabilisation phases during ois 5 during the last glacial four major periods of loess accumulation were likely to have occurred in europe at the harmignies section the oldest loess was deposited between 67 000 to 60 000 yr the second one from 60 000 to 50 000 yr the third one from 50 000 to 40 000 yr and the youngest loess accumulation period started most likely after the heinrich 3 event and lasted until the heinrich 2 event 25 000 20 000 yr two main periods of permafrost occurred at approximately 60 000 and 28 000 yr bp

biogeography of the pleistocene pleniglacial malacofaunas in europe stratigraphic and climatic implications abstract as determined by lozek malacological associations are significant of a particular vegetal environment in quaternary sequences different types of associations are recognized which can be assimilated to the present types of malacofaunas there are associations of grass group of forest group and of the ecotone of these two biogeographical entities on the european scale in pleistocene sequences the interglacial faunas indicate similarly the same differences as today being of stratigraphic interest on the contrary pleniglacial faunas which are mainly preserved in the loess belt seemed not interesting for stratigraphy since they indicate more generalized and more homogeneous conditions moreover they are composed of few species which for the most part had their distribution area destroyed by the ice cap advance yet the global analysis of pleniglacial biome faunas by ecological biogeographical approach provides a particular stratigraphic element which allows to determine stratigraphic entities provinces or domains in accordance with sedimentary interpretations so for quaternary pleniglacial faunas the biozone concept is efficiently supplied by ecostratigraphy consequently to a review of european localities it appears that the distribution of pleniglacial malacofaunas is mainly controlled by precipitations so the variations which are recorded in some privileged deposits as i e achenheim sequence in alsace france indicate variations through time of eastern limit of oceanic facies and western limit of continental facies of the climate

175 years of loess research in germany long records and unconformities abstract loess research in germany has a long tradition dating back to the early works of von leonhard von leonhard k c 1823 1824 charakteristik der felsarten 3 bde 772 s heidelberg j engelmann and his contemporary geoscientists ever since that time german researchers and loess research within germany have provided important contributions to the international state of the art to date however perceptual unconformities have existed in both the continuity of loess research in germany and the interpretation of the loess record in both the palaeoecological and the stratigraphic sense this paper briefly highlights some relevant periods of loess research in germany and the approaches adopted from the early days to the present the development of a refined stratigraphy of the last glacial loess in germany during the second half of the 20th century is reviewed in the contribution by a semmel fundamental contributions were first published by schonhals freising and brunnacker in the course of the subsequent work of the loess commission of the international union for quaternary research inqua the stratigraphy of the wurmian loess has since been refined in almost all loess regions of germany and schemes consistent in their fundamental features have been published in recent years contributions have focussed on age determination in particular those based on luminescence dating techniques

geochemistry unravels mis 3 2 paleoenvironmental dynamics at the loess paleosol sequence schwalbenberg ii germany abstract the schwalbenberg ii loess paleosol sequence lps denotes a key site for marine isotope stage mis 3 in western europe owing to eight succeeding cambisols which primarily constitute the ahrgau subformation therefore this lps qualifies as a test candidate for the potential of temporal high resolution geochemical data obtained by x ray fluorescence xrf scanning of discrete samples providing a fast and non destructive tool for determining the element composition the geochemical data is first contextualized to existing proxy data such as magnetic susceptibility ms and organic carbon corg and then aggregated to element log ratios characteristic for weathering intensity log ca sr log rb sr log ba sr log rb k and dust provenance log ti zr log ti al log si al generally an interpretation of rock magnetic particles is challenged in western europe where not only magnetic enhancement but also depletion plays a role our data indicates leaching and top soil erosion induced ms depletion at the schwalbenberg ii lps besides weathering log ca sr is susceptible for secondary calcification thus also log rb sr and log ba sr are shown to be influenced by calcification dynamics consequently log rb k seems to be the most suitable weathering index identifying the sinzig soils s1 and s2 as the most pronounced paleosols for this site sinzig soil s3 is enclosed by gelic gleysols and in contrast to s1 and s2 only initially weathered pointing to colder climate conditions also the remagen soils are characterized by subtle to moderate positive excursions in the weathering indices comparing the schwalbenberg ii lps with the nearby eifel lake sediment archive elsa and other more distant german austrian and czech lps while discussing time and climate as limiting factors for pedogenesis we suggest that the lithologically determined paleosols are in situ soil formations the provenance indices document a zr enrichment at the transition from the ahrgau to the hesbaye subformation this is explained by a conceptual model incorporating multiple sediment recycling and sorting effects in eolian and fluvial domains

new perspectives on the li isotopic composition of the upper continental crust and its weathering signature abstract lithium isotopes are increasingly used to trace both present day and past weathering processes at the surface of the earth and could potentially be used to evaluate the average degree of past weathering recorded by the upper continental crust ucc yet the previous estimate of average 7li of the ucc has a rather large uncertainty hindering the use of li isotopes for this purpose new 7li for desert and periglacial loess deposits windblown dust from several parts of the world europe argentina china and tajikistan demonstrate that the former are more homogeneous than the latter and may therefore serve as excellent proxies of the average composition of large tracts of the ucc the li isotopic compositions and concentrations of desert loess samples are controlled by eolian sorting that can be quantified by a binary mixing between a weathered fine grained end member dominated by phyllosilicates and having low 7li and an unweathered coarse grained end member that is a mixture of quartz and plagioclase having higher 7li we use correlations between insoluble elements ree nd hf and fe2o3 sio2 li concentrations henceforth referred as li and 7li to estimate a new more precise average li isotopic composition and concentration for the ucc li 30 5 3 6 2 ppm and li 7 0 6 0 6 2 the 7li for desert loess deposits is anti correlated with the chemical index of alteration cia using this relationship along with our average 7li we infer that 1 the present day cia of the average ucc is 61 2 4 2 higher than the common reference value of 53 and 2 the average proportion of chemically weathered components is as high as 37 10 17 2 at the surface of the earth

some observations on colocated and closely spaced strong ground motion records of the 1999 chi chi taiwan earthquake the digital accelerograph network installed in taiwan produced a rich set of records from the 20 september 1999 chi chi taiwan earthquake mw 7 6 teledyne geotech model a 800 and a 900a digital accelerographs were colocated at 22 stations that recorded this event comparisons of the amplitudes frequency content and baseline offsets show that records from several of the a 800 accelero graphs are considerably different than those from the colocated a 900a accelero graphs on this basis and in view of the more thorough predeployment testing of the newer a 900a instruments we recommend that the records from the a 800 instruments be used with caution in analyses of the mainshock and aftershocks at the hualien seismic station two a 900a and one a 800 instruments were colocated along with a global positioning system instrument although the records from the two a 900a instruments are much more similar than those from a colocated a 800 instrument both three component records contain unpredictable baseline offsets which produced completely unrealistic ground displacements derived from the ac celerations by double integration as do many of the strong motion data from this event the details of the baseline offsets differ considerably on the two three component records there are probably numerous sources of the baseline offsets including sources external to the instruments such as tilting or rotation of the ground and sources internal to the instruments such as electrical or mechanical hysteresis in the sensors for the two colocated a 900a records at the hualien seismic station however the differences in the baseline offsets suggest that the principal source is some transient disturbance within the instrument the baseline offsets generally man ifest themselves in the acceleration time series as pulses or steps either singly or in combination we find a 0 015 hz low cut filter can almost completely eliminate the effects of the baseline offsets but then information regarding the permanent dis placements is lost the causative mechanisms of the baseline offsets are unknown presently hence it is very difficult to recover the permanent displacements from the modern digital records although for records close to large earthquakes the signal to noise ratio should theoretically be adequate to obtain ground motions with periods of hundreds of seconds this study reinforces our conclusion from previous studies that the sources of baseline offsets occurring in digital strong motion records are very complex and often unpredictable and that therefore it is difficult to remove the baseline effects to maximize the information content of the record the baseline offsets only affect very long period motions e g 20 sec however and therefore are of little or no engineering concern

the late pleistocene loess palaeosol sequence of middle belgium abstract in belgium two areas show extended late pleistocene loess cover the hesbaye close to liege and the haine basin around mons for decades correlation between both areas remained problematic here we will show how by way of complementary approaches the records of the haine and the hesbaye could be inserted into a high resolution pedosedimentary sequence encompassing the major part of the late pleistocene and reproducible at the scale of the belgian loess belt based on the pedosedimentary and palaeoenvironmental signatures of the belgian sequence comparisons are proposed with high resolution loess sequences of eastern europe and central siberia they give access to well documented palynological data for the first part of the late pleistocene and to a strong climatic record on loess framed between 45 and 10 ka bp by long series of radiocarbon dates on charcoal and wood remains the conjunction of these complementary loess records has further given way to a consistent proxy correlation scheme linking a high resolution continental climatic record to the greenland ice sequence

late quaternary ice sheet history of northern eurasia the maximum limits of the eurasian ice sheets during four glaciations have been reconstructed 1 the late saalian 140 ka 2 the early weichselian 100 80 ka 3 the middle weichselian 60 50 ka and 4 the late weichselian 25 15 ka the reconstructed ice limits are based on satellite data and aerial photographs combined with geological field investigations in russia and siberia and with marine seismic and sediment core data the barents kara ice sheet got progressively smaller during each glaciation whereas the dimensions of the scandinavian ice sheet increased during the last ice age the barents kara ice sheet attained its maximum size as early as 90 80 000 years ago when the ice front reached far onto the continent a regrowth of the ice sheets occurred during the early middle weichselian culminating about 60 50 000 years ago during the late weichselian the barents kara ice sheet did not reach the mainland east of the kanin peninsula with the exception of the nw fringe of taimyr a numerical ice sheet model forced by global sea level and solar changes was run through the full weichselian glacial cycle the modeling results are roughly compatible with the geological record of ice growth but the model underpredicts the glaciations in the eurasian arctic during the early and middle weichselian one reason for this is that the climate in the eurasian arctic was not as dry then as during the late weichselian glacial maximum

landscape instability at the end of mis 3 in western central europe evidence from a multi proxy study on a loess palaeosol sequence from the eastern lower rhine embayment germany abstract the lower rhine embayment hosts important loess palaeosol sequences lps within the western european loess belt yielding valuable information on landscape evolution and palaeoclimatic dynamics the study focusses on the palaeoenvironmental development based on a lps from the eastern shoulder of the lower rhine embayment dusseldorf grafenberg the palaeoenvironmental development within the study area is presented and discussed based on high resolution grain size analyses selected environmental magnetic parameters and geochemical analyses complemented by luminescence age estimates differences in grain size distribution gsd as well as the u ratio clearly reflect main stratigraphical units within the lps in addition the centered log ratio transformation of gsd gsd clr which is sensitive to post depositional grain size variations traces units of intensified soil formation despite no magnetic enhancement can be observed within the grafenberg lps environmental magnetic parameters combined with selected geochemical analyses sr rb provide direct information on the modification of silicates and magnetic minerals in the course of pedogenesis and diagenesis overall the grafenberg lps contributes to the understanding of environmental conditions within the lower rhine embayment particularly for the late mis 3 and the transition to mis 2 the lps reflects major shifts in the geomorphic system which are compared to palaeoenvironmental records from different archives and different geographic regions in north western europe indicating a direct relation to north atlantic climate oscillations during the last glacial period it is shown that the hesbaye unconformity at the mis 3 2 boundary is bound to an erosional event which can be traced over wide areas within the northern european loess belt

geochemistry and mineralogy of the late pleistocene loess palaeosol sequence in zlota near sandomierz poland implications for weathering sedimentary recycling and provenance abstract in order to determine the provenance of material the late pleistocene loess palaeosol sequence in zlota poland was analysed geochemically icp ms icp es and mineralogically qemscan investigating simultaneously the weathering signature and effect of sedimentary sorting a total number of 39 loess and soil samples were tested for the geochemical composition and 5 for the mineralogy the investigated samples compared to upper continental crust are enriched with elements such as si zr hf nb ta th u and rare earth elements especially the heavy rare earth elements related rather to felsic igneous rocks the enrichment of only two mafic elements ti and cr can be explained by heavy minerals admixture loess in zlota is strongly mixed and homogenized during transportation and or sedimentary recycling for each sample the uniform shape of the chondrite normalized rare earth elements patterns were found characterized by steep light rare elements lan smn 3 45 4 08 avg 3 81 constant negative eu anomalies eu eu 0 50 0 63 avg 0 56 and distinctly flat heavy rare earth elements gdn ybn 1 17 1 45 avg 1 28 the material is not significantly affected by chemical weathering and the post depositional modifications are not particularly important for the trace element composition both in loess and soils e g th u 3 1 4 65 avg 3 64 ce ce 0 96 1 09 avg 1 01 lan ybn 6 22 7 93 avg 6 94 the research reveals that relatively fresh felsic related parent material has been well mixed during transportation but post depositional alterations related only to the pedogenesis have not been intense enough to mask their chemical signature the investigated material has been probably originated in scandinavia likely norway but deflated directly from the glacial drift covering the terrain of poland

oxygen isotope and palaeotemperature records from six greenland ice core stations camp century dye 3 grip gisp2 renland and northgrip oxygen isotope variations spanning the last glacial cycle and the holocene derived from ice core records for six sites in greenland camp century dye 3 grip gisp2 renland and northgrip show strong similarities this suggests that the dominant influence on oxygen isotope variations reflected in the ice sheet records was regional climatic change differences in detail between the records probably reflect the effects of basal deformation in the ice as well as geographical gradients in atmospheric isotope ratios palaeotemperature estimates have been obtained from the records using three approaches i inferences based on the measured relationship between mean annual 18o of snow and of mean annual surface temperature over greenland ii modelled inversion of the borehole temperature profile constrained either by the dated isotopic profile or iii by using monte carlo simulation techniques the third of these approaches was adopted to reconstruct holocene temperature variations for the dye 3 and grip temperature profiles which yields remarkably compatible results a new record of holocene isotope variations obtained from the northgrip ice core matches the grip short term isotope record and also shows similar long term trends to the dye 3 and grip inverted temperature data the northgrip isotope record reflects i a generally stronger isotopic signal than is found in the grip record ii several short lived temperature fluctuations during the first 1500 yr of the holocene iii a marked cold event at ca 8 2 ka the 8 2 ka event iv optimum temperatures for the holocene between ca 8 6 and 4 3 ka a signal that is 0 6 stronger than for the grip profile v a clear signal for the little ice age and vi a clear signal of climate warming during the last century these data suggest that the northgrip stable isotope record responded in a sensitive manner to temperature fluctuations during the holocene copyright 2001 john wiley sons ltd

paleogeographic implications of an erosional remnant of paleogene rocks southwest of the sur nacimiento fault zone southern coast ranges california a small tract of heretofore unrecognized paleogene rocks lies about 30 km northeast of santa maria and 1 km southwest of the sur nacimiento fault zone near upper pine creek this poorly exposed assemblage of rocks is less than 50 m thick lies unconformably on regionally distributed upper cretaceous submarine fan deposits and consists of three units fossiliferous lower eocene mudstone oligocene conglomerate and basaltic andesite that has a radiometric age of 26 6 0 5 ma both the sedimentary and igneous constituents in the paleogene sequence are unlike those of known sequences on either side of the sur nacimiento fault zone conventional paleogeographic restorations need to be modified to accommodate the conditions of deposition and emplacement represented by the three rock units the paleogene sedimentary rocks near upper pine creek presumably are remnants of formerly widespread early eocene bathyal deposits and locally distributed oligocene fluvial deposits southwest of the fault zone the 26 6 ma basaltic andesite however may not have extended much beyond its present outcrops although the history nature and amount of pre miocene slip along the sur nacimiento fault zone are not resolved an episode of oligocene displacement is required by the contrast in thicknesses depositional patterns and paleobathymetry of the juxtaposed rock sequences

nomenclature of amphiboles additions and revisions to the international mineralogical associations amphibole nomenclature the introduction of a fifth amphibole group the na ca mg fe mn li group defined by 0 50 b mg fe 2 mn 2 li 1 50 and 0 50 b ca na 1 50 apfu atoms per formula unit with members whittakerite and ottoliniite has been required by recent discoveries of b lina amphiboles this and other new discoveries such as sodicpedrizite which is herein slightly but significantly changed from the original idealized formula necessitate amendments to the ima 1997 definitions of the mg fe mn li calcic sodic calcic and sodic groups the discovery of obertiite and the finding of an incompatibility in the ima 1997 subdivision of the sodic group requires further amendments within the sodic group all these changes which have ima approval are summarized

origin and paleoclimatic significance of late quaternary loess in nebraska evidence from stratigraphy chronology sedimentology and geochemistry muhs d r bettis iii e a aleinikoff j n mcgeehin j p beann j skipp g marshall b d roberts h m johnson w c benton r 2008 origin and paleoclimatic significance of late quaternary loess in nebraska evidence from stratigraphy chronology sedimentology and geochemistry gsa bulletin 120 11 12 1378 1407

imprint of north atlantic abrupt climate changes on western european loess deposits as viewed in a dust emission model abstract western european loess sequences of the last glaciation 100 000 15 000 years bp exhibit strong cyclic variations of the sedimentation rate which are coeval to the greenland stadial interstadial cycles and the heinrich events these north atlantic rapid climate changes appear thus as a potential cause for the sedimentation variations via changes in dust intensity cycle here we make a first step in testing this hypothesis by modelling the impact of the north atlantic abrupt climate variations on dust emission our dust emission calculations use meteorological fields generated by the lmdz atmospheric general circulation model at a resolution down to 60 km over western europe three numerical experiments are run representing a greenland stadial an interstadial and a heinrich event orbital parameters and ice sheet configuration correspond to conditions from marine isotope stage 3 60 000 25 000 years bp a period characterized by strong millennial scale climate variability the only differences we impose in the boundary conditions regard the north atlantic surface temperature and sea ice cover in the latitudinal band 30 63 n the changes in wind precipitation soil moisture and snow cover from one simulated state to another result in small differences in dust emission intensity in contrast when the inhibition of the aeolian erosion by vegetation is taken into account the dust fluxes for the cold climate states greenland stadial and heinrich event become generally more than twice higher than those for the relatively warmer greenland interstadial in agreement with the loess data these results support the hypothesis that the north atlantic millennial scale variability is imprinted in western european loess profiles and point to vegetation changes as the main factor responsible for millennial scale sedimentation variations an analysis for the english channel and southern north sea areas major potential dust sources shows that the seasonality of dust emission is not controlled by the wind speed as in modern large deserts but by the surface conditions consequently the dusty season lasts from late winter to early summer with maximum activity in april may and is shifted towards summer when the climate is colder

the late pleistocene loess deposits and palaeosols of eastern belgium new tl age determinations fourteen samples from the pleistocene loess exposures at kesselt belgian limbourg have been dated with the thermoluminescence method using the regeneration technique and a double analysis with two types of blue transmittant filters reproducible age estimates were obtained up to about 130 140 ka for the basal part of the late weichselian brabant loess and the underlying cryorurbated nagelbeek horizon we arrived at ages of 20 22 ka which is consistent with the radiocarbon age of this horizon 22 3 ka our tl dates further constrain the formation of a lower luvisol profile the bt horizon of which has been correlated with the rocourt palaeosol to the period 50 60 ka these dates however may overstimate the true age of the sediment because they were obtained on reworked loess they indicate that this palaeosol was formed during a middle weichselian interstadial and not during the eemian as is generally accepted the boundary between the weichselian and the older loess is situated at a lower level in the kesselt profile the loess bracketing the deeper tundra gleysols yielded tl ages up to 130 140 ka and the ages further rapidly increased with depth indicating that the sediments may even be much older than saalian 1998 john wiley sons ltd

gondwana derived microcontinents the constituents of the variscan and alpine collisional orogens abstract the european variscan and alpine mountain chains are collisional orogens and are built up of pre variscan building blocks which in most cases originated at the gondwana margin such pre variscan elements were part of a pre ordovician archipelago like continental ribbon in the former eastern prolongation of avalonia and their present day distribution resulted from juxtaposition through variscan and or alpine tectonic evolution the well known nomenclatures applied to these mountain chains are the mirror of variscan resp alpine organization it is the aim of this paper to present a terminology taking into account their pre variscan evolution at the gondwana margin they may contain relics of volcanic islands with pieces of cadomian crust relics of volcanic arc settings and accretionary wedges which were separated from gondwana by initial stages of rheic ocean opening after a short lived ordovician orogenic event and amalgamation of these elements at the gondwanan margin the still continuing gondwana directed subduction triggered the formation of ordovician al rich granitoids and the latest ordovician opening of palaeo tethys an example from the alps external massifs illustrates the gradual reworking of gondwana derived pre variscan elements during the variscan and alpine tertiary orogenic cycles

tephrochronology and the extended intimate integration of ice core marine and terrestrial records event stratigraphy 8 128 ka b2k the comparison of palaeoclimate records on their own independent timescales is central to the work of the intimate integrating ice core marine and terrestrial records network for the north atlantic region an event stratigraphy has been established from the high precision greenland ice core records and the integrated gicc05 chronology this stratotype provides a palaeoclimate signal to which the timing and nature of palaeoenvironmental change recorded in marine and terrestrial archives can be compared to facilitate this wider comparison without assuming synchroneity of climatic change proxy response intimate has also focussed on the development of tools to achieve this in particular the use of time parallel marker horizons e g tephra layers volcanic ash coupled with the recent temporal extension of the greenland stratotype as part of this special issue we present an updated intimate event stratigraphy highlighting key tephra horizons used for correlation across europe and the north atlantic we discuss the advantages of such an approach and the key challenges for the further integration of terrestrial palaeoenvironmental records with those from ice cores and the marine realm

dust sources and deposition during the last glacial maximum and current climate a comparison of model results with paleodata from ice cores and marine sediments mineral dust aerosols in the atmosphere have the potential to affect the global climate by influencing the radiative balance of the atmosphere and the supply of micronutrients to the ocean ice and marine sediment cores indicate that dust deposition from the atmosphere was at some locations 2 20 times greater during glacial periods raising the possibility that mineral aerosols might have contributed to climate change on glacial interglacial time scales to address this question we have used linked terrestrial biosphere dust source and atmospheric transport models to simulate the dust cycle in the atmosphere for current and last glacial maximum lgm climates we obtain a 2 5 fold higher dust loading in the entire atmosphere and a twenty fold higher loading in high latitudes in lgm relative to present comparisons to a compilation of atmospheric dust deposition flux estimates for lgm and present in marine sediment and ice cores show that the simulated flux ratios are broadly in agreement with observations differences suggest where further improvements in the simple dust model could be made the simulated increase in high latitude dustiness depends on the expansion of unvegetated areas especially in the high latitudes and in central asia caused by a combination of increased aridity and low atmospheric co2 the existence of these dust source areas at the lgm is supported by pollen data and loess distribution in the northern continents these results point to a role for vegetation feedbacks including climate effects and physiological effects of low co2 in modulating the atmospheric distribution of dust

predictive model of san andreas fault system paleogeography late cretaceous to early miocene derived from detailed multidisciplinary conglomerate correlations abstract paleogeographic reconstruction of the region of the san andreas fault system in western california usa was hampered for more than two decades by the apparent incompatibility of authoritative lithologic correlations these led to disparate estimates of dextral strike slip offsets across the san andreas fault notably 315 km between pinnacles and neenach volcanics versus 563 km offset between anchor bay and eagle rest peak furthermore one section of the san andreas fault between pinnacles and point reyes had been reported to have six pairs of features showing only 30 km offset while several younger features in that same area were reported consistent with 315 km offset estimates of total dextral slip on the adjoining san gregorio fault have ranged from 5 km to 185 km sixteen upper cretaceous and paleogene conglomerates of the california coast ranges from anchor bay to simi valley were included in a multidisciplinary study centered on identification of matching unique clast varieties rather than on simply counting general clast types detailed analysis verified the prior correlation of the upper cretaceous strata of anchor bay at anchor bay with a then unnamed conglomerate at highway 92 and skyline road south of san francisco and verified that the paleocene or eocene point reyes conglomerate at point reyes is a tectonically displaced segment of the carmelo formation of point lobos near monterey the work also led to three new correlations point reyes conglomerate with granitic source rock at point lobos a magnetic anomaly at black point near sea ranch with a magnetic anomaly near san gregorio and strata of anchor bay with previously established source rock the potassium poor logan gabbro of eagle rest peak at a more recently recognized subsurface location just east of the san gregorio fault south of san gregorio from these correlations a late cretaceous to early oligocene paleogeography was constructed which was unique in utilizing modern shapes of tectonic blocks in a paleogeographic resolution synthesizing both the proposed 315 and 30 km san andreas fault offsets as well as honoring the lithologic correlation of anchor bay with eagle rest peak the model has proved predictive since its first introduction in april and june 1998 other authors have reported seven subsequently identified correlative pairs of geological and geophysical features consistent with it these required both lateral and temporal expansion of the model the paleogeography now incorporates 58 pairs of correlative features covers the period from 70 to 21 3 ma and extends from pelona and orocopia to the mendocino triple junction the model supports the view that fault is not the boundary between the pacific and north american plates is a wide zone encompassing the san andreas fault system however the model suggests the san andreas fault is a temporary assemblage of separate segments having different motions and is neither the primary plate boundary nor the dominant fault of the san andreas fault system by improving resolution of complex spatial temporal distribution of slip along this evolving tectonic margin the model provides a firmer foundation for resolution of geophysical issues such as slab window and pacific plate subduction models

multi isotope approach δ44 40ca δ88 86sr and 87sr 86sr provides insights into rhizolith formation mechanisms in terrestrial sediments of nussloch germany abstract carbonates in loess paleosol sequences are considered as a valuable paleoenvironmental proxy for climate change during the quaternary period in this study we propose a new dataset of 44 40ca 88 86sr and 87sr 86sr to understand the formation of rhizoliths roots encrusted with caco3 within these kinds of sequences from nussloch region germany our results indicate that the leached fractions of rhizoliths sampled at 3 25 m 6 65 m and 8 45 m depths and leached with hcl have lower 44 40ca and 88 86sr and higher 87sr 86sr isotopic values than the leached fractions of rhizosphere and root free loess of the same stratigraphic levels this suggests different mechanisms of carbonate formation and different sources of sr and ca a three steps model of formation of rhizoliths from nussloch has been proposed first of all the roots grow in an existent stratigraphic level and the biological activity associated with roots allows for the dissolution of carbonate and non carbonate minerals a part of the available ca and sr is taken up by roots which absorb preferentially the light isotopes e g 40ca and 86sr a higher rate of water absorption by roots than nutrients in association with co2 released by biological respiration allows to reach supersaturation with respect to caco3 the precipitation of rhizolith carbonate selects preferentially the light isotopes e g 40ca and 86sr leading to lower 44 40ca and 88 86sr isotope values than the ones recorded on the closest rhizosphere and loess the higher 87sr 86sr signatures of rhizolith carbonates which is not modified by root uptake or by precipitation processes is the result of a mixture between 87sr 86sr signatures of carbonate and non carbonate minerals digested around the roots nevertheless grey zones remain in this main hypothesis about the very high contribution of residue materials to the isotopic signatures of rhizoliths in this light other mechanisms of downward transfer of ca and sr from upper stratigraphic level that could imprint the leached fractions of rhizoliths have been discussed

a new key site for the end of lower palaeolithic and the onset of middle palaeolithic at etricourt manancourt somme france new palaeolithic sites are rare for mis 11 to 9 in eurasia the discovery and the excavation of a large new site in 2012 at etricourt manancourt somme france is an exceptional event in 2010 a palaeolithic evaluation was undertaken at a future retention basin by emilie goval on 170 000 square metres the evaluation produced many flint artefacts demonstrating the existence of at least two important middle palaeolithic sites in 2012 an excavation on one of the sites was conducted by david herisson over 6 months and covering 4500 square metres this excavation was undertaken by a multidisciplinary scientific team including prehistorians and geomorphologists this allows us to apply a reliable chronostratigraphic approach based on the analysis of the glacial interglacial successions five in situ palaeolithic occupations have been excavated dating from 330 to 70 ka the youngest occupation dates from 70 to 80 ka weichselian and corresponds to a recent phase of the middle palaeolithic the next two layers belong to the early middle palaeolithic between 190 and 240 ka saalian finally the two oldest layers have dates between 330 and 280 ka saalian and belong to the lower palaeolithic in addition to the archaeology the sedimentary sequence is very thick 11 m high and presents for the first time in northern france a detailed record of the three last interglacial glacial cycles this paper presents the first archaeological and chronostratigraphic results of the excavation of etricourt manancourt and its input with high resolution data to discuss behavioural changes occurring at the end of the lower palaeolithic and the onset of the middle palaeolithic c 2016 elsevier ltd and inqua all rights reserved

estimating permanent ground displacement from near fault strong motion accelerograms this study presents a three phase algorithm that uses the discrete wavelet transform dwt to make the baseline correction to near fault ground motion accelerogram and to estimate permanent ground displacement the developed algorithm is applied to the near fault ground motion data collected from the 1999 chi chi taiwan earthquake in phase i the peak ground displacement is estimated through the decomposition of acceleration data in phase ii the residual deformation of the ground is estimated from the decomposition of the velocity data combining phase i and phase ii enables the near fault ground displacement with residual deformation to be estimated the estimated permanent ground deformation is compared with that indicated by nearby global positioning system gps data before and after the earthquake the obtained residual ground deformation correlates well with that obtained by gps measurement

change in atmospheric mineral aerosols in response to climate last glacial period preindustrial modern and doubled carbon dioxide climates desert dust simulations generated by the national center for atmospheric research s community climate system model for the current climate are shown to be consistent with present day satellite and deposition data the response of the dust cycle to last glacial maximum preindustrial modern and doubled carbon dioxide climates is analyzed only natural non land use related dust sources are included in this simulation similar to some previous studies dust production mainly responds to changes in the source areas from vegetation changes not from winds or soil moisture changes alone this model simulates a 92 33 and 60 change in dust loading for the last glacial maximum preindustrial and doubled carbon dioxide climate respectively when impacts of carbon dioxide fertilization on vegetation are included in the model terrestrial sediment records from the last glacial maximum compiled here indicate a large underestimate of deposition in continental regions probably due to the lack of simulation of glaciogenic dust sources in order to include the glaciogenic dust sources as a first approximation we designate the location of these sources and infer the size of the sources using an inversion method that best matches the available data the inclusion of these inferred glaciogenic dust sources increases our dust flux in the last glacial maximum from 2 1 to 3 3 times current deposition

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

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

late pleistocene loess of the lower rhine abstract from the lower rhine a compiled 25 7 m thick late pleistocene loess paleosol sequence is differentiated into five lithostratigraphic units the rheingau member mis 5 the keldach member weichselian early pleniglacial gs 21 1 18 mis 4 the ahrgau member weichselian middle pleniglacial mis 3 and the hesbaye and brabant members weichselian late pleniglacial mis 2 it correlates well with climate fluctuations known from ice cores and deep sea cores the sequence was continuously sampled by 335 samples it cuts through all essential layers and soils of the late pleistocene upper loess formation a continuous coarse silt index csi curve shows a maximum in the hesbaye member 31 24 ka b2k indicating the strongest wind conditions during the early late pleistocene further csi highs lie in the keldach and early brabant members csi lows are found the early and middle rheingau member gi 25 gi 22 the jackerath spenrath soils within the deeper keldach member gi 20 19 the early ahrgau member gi 17 gi 12 and finally in the elfgen soil gi 2 at the base of the brabant member the organic carbon culminates in the titz humus zone presumably at the end of gi 21 indicating scanty oxidation during the following cold lower weichselian pleniglacial period the garzweiler solcomplex forming a prevailing period of soil formation between 130 and 78 ka bp mis 5e a is considered as interglacial complex rhine interglacial complex continuing the style of the older interglacial complexes of mis 7 9 etc the ahr interstadial complex mis 3 is seen as immature complex of warm phases with fabric of the interglacial complexes author s suggestion the rhine interglacial complex covers mis 5e a and restricts the weichselian glacial to mis 4 through mis 2 this procedure follows the style of the older interglacial complexes

preseismic deformation and coseismic displacements associated with the 1999 chi chi taiwan earthquake the destructive 1999 chi chi taiwan earthquake m w 7 5 produced an approximately 100 km long surface rupture mostly along the previously recognized north south trending chelungpu fault preseismic deformation in central taiwan is realized from annually repeated global positioning system gps data acquired during the 1992 1999 period the total wnw ese shortening rate in the vicinity of the epicentral region that is from the west coast to the western boundary of the central range is up to 25 mm yr the crustal deformation before the chi chi earthquake was essentially a uniaxial compressional strain of 0 36 strain yr in the direction of 114 the gps measurements taken 0 2 2 7 yr before and within 3 months after the mainshock were utilized to estimate the coseismic displacements horizontal movements of 1 1 9 1 m in the nw nnw directions are observed on the hanging wall eastern side of the fault there is a northward increasing trend in the magnitude of the displacement vectors and a dramatic change in the direction of about 50 toward the east along the fault strike in contrast much smaller se see movements of 0 1 1 5 m are found on the footwall western side of the fault the gps data show 2 4 10 1 m of total horizontal offsets across the chelungpu fault vertical offsets of 1 2 4 4 m with the eastern side up are also observed along the surface rupture the uplift on the hanging wall decreases rapidly toward the east it becomes subsidence at sun moon lake and in the puli wushe area the stations on the footwall show subsidence of 0 02 0 26 m the width of the uplift zone increases from about 10 km in the south to approximately 30 km in the north manuscript received 13 october 2000

last glacial aeolian landforms and deposits in the rhone valley se france spatial distribution and grain size characterization abstract in the rhone valley a north south oriented cenozoic rift in southeast france thick pleistocene loess deposits have been recognized since the beginning of the last century these loess records which are disconnected from the north european loess belt nelb are of significant interest to document the evolution of perimediterranean landscapes and environments during the last glacial to overcome the poor precision of available aeolian distribution maps aeolian deposits were mapped using the topsoil textural database provided by the land use and cover area frame statistical survey project lucas the grain size distribution of aeolian sand and loess was first determined using 116 samples taken from surveyed outcrops then the areas showing a similar grain size composition were extracted from the lucas rasters the resulting map reproduces the conventional maps correctly but suggests a more significant extension of loess in better agreement with the known distribution of outcrops the map shows that the distinctive morphology of the valley dominantly controls the distribution of aeolian deposits the deflation related landforms i e yardangs closed depressions pans and desert pavements are widespread south of narrowings of the rhone valley between latitudes 44 n and 45 n they indicate palaeowinds blowing from the north northwest aeolian sand loessic sand sandy loess and loess deposits successively spread on both sides of the rhone river the loess is characterized by a coarse texture main mode around 60 m strong local thickness 5 m limited extension and abundant bioturbation this preservation results from the persistence of a shrub vegetal cover during the coldest and driest phases of the last glacial that allowed for trapping the saltating and suspended particles close to the alluvial sources

effect of baseline corrections on displacements and response spectra for several recordings of the 1999 chi chi taiwan earthquake displacements derived from many of the accelerogram recordings of the 1999 chi chi taiwan earthquake show drifts when only a simple baseline de rived from the pre event portion of the record is removed from the records the appearance of the velocity and displacement records suggests that changes in the zero level of the acceleration are responsible for these drifts the source of the shifts in zero level are unknown but in at least one case it is almost certainly due to tilting of the ground this article illustrates the effect on the ground velocity ground dis placement and response spectra of several schemes for accounting for these baseline shifts a wide range of final displacements can be obtained for various choices of baseline correction and comparison with nearby gps stations none of which are colocated with the accelerograph stations do not help in choosing the appropriate baseline correction the results suggest that final displacements estimated from the records should be used with caution the most important conclusion for earthquake engineering purposes however is that the response spectra for periods less than about 20 sec are usually unaffected by the baseline correction although limited to the analysis of only a small number of recordings the results may have more general significance both for the many other recordings of this earthquake and for data that will be obtained in the future from similar high quality accelerograph networks now being installed or soon to be installed in many parts of the world

tl stratigraphy of pre weichselian loess from nw europe using feldspar coarse grains abstract a new feldspar relative tl dating method is proposed that enables dating of pre weichselian loess older than 130 ka by applying the additive dose technique and the mejdahl s exponential extrapolation to alkali feldspar coarse grains the method is applied to loess deposits from various reference loessic sections of nw europe our relative tl age estimates are consistent with the information provided by the regional stratigraphy furthermore they lead to a clear separation of the pre weichselian periods of loess deposition in the time period 130 ka 300 ka

implications of volcanism in coastal california for the neogene deformation history of western north america 1 the geologic record of coastal california includes evidence of numerous volcanic centers younger than 30 ma that do not appear to have erupted in an arc setting by correlating these volcanic centers with specific slab windows predicted from analysis of magnetic anomalies on the pacific plate we add new constraints to tectonic reconstructions since 30 ma our correlations such as erupting the morro rock islay hill complex south of the pioneer fracture zone and the iversen basalt south of the mendocino fracture zone require larger displacements within western north america than advocated by most previous authors specifically we infer at least 315 km of motion between the sierra nevada and rigid north america at an azimuth of about n60 w and at least 515 km between baja california and rigid north america in a similar direction a consequence of inferring a large displacement of baja california is that the pacific north american plate boundary must have developed most of its current form prior to 10 ma we interpret a slab window developing between cocos and monterey plates after 19 ma that reconstructs under nearly all of the southern california volcanic centers dated at 18 14 ma most of the sedimentary basins associated with volcanic rocks show brief periods of rapid subsidence synchronous with volcanism followed by slow subsidence of variable but often extended duration consistent with rapid extension of cold lithosphere over recently introduced hot asthenosphere

evidence for massive discharges of icebergs into the north atlantic ocean during the last glacial period sediments in the north atlantic ocean contain a series of layers that are rich in ice rafted debris and unusually poor in foraminifera1 here we present evidence that the most recent six of these heinrich layers deposited between 14 000 and 70 000 years ago record marked decreases in sea surface temperature and salinity decreases in the flux of planktonic foraminifera to the sediments and short lived massive discharges of icebergs originating in eastern canada the path of the icebergs clearly marked by the presence of ice rafted detrital carbonate can be traced for more than 3 000 km a remarkable distance attesting to extreme cooling of surface waters and enormous amounts of drifting ice the cause of these extreme events is puzzling they may reflect repeated rapid advances of the laurentide ice sheet perhaps associated with reductions in air temperatures yet temperature records from greenland ice cores appear to exhibit only a weak corresponding signal moreover the 5 10 000 yr intervals between the events are inconsistent with milankovitch orbital periodicities raising the question of what the ultimate cause of the postulated cooling may have been

middle and late pleistocene loess of the western ciscaucasia stratigraphy lithology and composition due to the high preservation of the loess series and the availability of coastal outcrop sections loess cover of western ciscaucasia has ample opportunities for spatial paleogeographical reconstructions for the middle and late pleistocene currently the level of knowledge on the structure and composition of the loess paleosol sequences of western ciscaucasia remains unequal the azov coast is studied in more detail in comparison with the inner part of the region the structure and composition of the loess paleosol sequences of different parts of western ciscaucasia the sea of azov coast and western macroslope of the stavropol upland for the middle and late pleistocene are compared comparison of the loess paleosol sequences key sections are based on investigations of litho and pedostratigraphy magnetic susceptibility grain size elemental and mineral composition and luminescence dating recent results of luminescence dating allowed correcting the structure of the mezin pedocomplex s1 it was found out that this pedocomplex includes three phases of soil formation s1ss1 s1ss2 s1ss3 which approximately correspond to the warm stages of marine isotope stage 5 mis 5 5a 5c 5e in all sections a clear trend towards an increase in the accumulation rates over the last three climatic macrocycles is observed the last interglacial glacial macrocycle miss 2 5 is characterized by the most significant increase in average accumulation rates which were 1 8 times higher compared to miss 6 7 and 2 3 times higher than during the miss 8 9 a likely reason for the regional increase in the average dust accumulation rate was the directional increase in climate aridity the patterns of the spatial distribution of the loess thickness and material composition indicate that the main source of aeolian dust is situated in the east we suppose that the main sources of dust are sand masses of the alluvial plains of lover volga terek kuma and kura rivers in the caspian lowland the lower don sandy province is reconstructed to be a secondary source dust is blown from the sandy terraces of the don and in the past from the don deltas during the period when the sea of azov dried up

the last interglacial palaeosol in the belgian loess belt tl age record abstract in the belgian loess plateau the rocourt soil is a well known luvisol horizon that is regarded as representing the last interglacial the name of the soil comes from the locality of rocourt in the east of the country where it has been observed for the first time later exposures of a similar soil were found in other localities most typically a sequence of three horizons is observed a red brown illuvial bt horizon overlain by a bleached horizon and a compound dark horizon in this paper we present the results of tl age determinations obtained on sediments directly bracketing the soil at the type locality of rocourt and at the locality of momalle more to the west together with some supplementary data for the exposures at kesselt to check a controversial result that was obtained earlier j quaternary sci 13 5 1998 487 the tl analyses involved both the total bleach additive dose and regeneration methods our tl ages confirm the assumed chronostratigraphic position oxygen isotope stage 5 of the soil exposed at the type locality the ages obtained at momalle and kesselt indicate that we are dealing with the same soil here but the palaeodose data are less consistent this is probably due to the fact that the loess has been disturbed by post depositional processes such as solifluction surface run off cryo and bioturbation this seems to be a major problem with the sediments in the eastern part of the belgian loess belt

denudation of the continental shelf between britain and france at the glacial interglacial timescale the erosional morphology preserved at the sea bed in the eastern english channel dominantly records denudation of the continental shelf by fluvial processes over multiple glacial interglacial sea level cycles rather than by catastrophic flooding through the straits of dover during the mid quaternary here through the integration of multibeam bathymetry and shallow sub bottom 2d seismic reflection profiles calibrated with vibrocore records the first stratigraphic model of erosion and deposition on the eastern english channel continental shelf is presented published optical stimulated luminescence osl and 14c ages were used to chronometrically constrain the stratigraphy and allow correlation of the continental shelf record with major climatic sea level periods five major erosion surfaces overlain by discrete sediment packages have been identified the continental shelf in the eastern english channel preserves a record of processes operating from marine isotope stage mis 6 to mis 1 planar and channelised erosion surfaces were formed by fluvial incision during lowstands or relative sea level fall the depth and lateral extent of incision was partly conditioned by underlying geology rock type and tectonic structure climatic conditions and changes in water and sediment discharge coupled to ice sheet dynamics and the drainage configuration of major rivers in northwest europe evidence for major erosion during or prior to mis 6 is preserved fluvial sediments of mis 2 age were identified within the northern palaeovalley providing insights into the scale of erosion by normal fluvial regimes seismic and sedimentary facies indicate that deposition predominantly occurred during transgression when accommodation was created in palaeovalleys to allow discrete sediment bodies to form sediment reworking over multiple sea level cycles saalian eemian early weichselian by fluvial coastal and marine processes created a multi lateral multi storey succession of palaeovalley fills that are preserved as a strath terrace the data presented here reveal a composite erosional and depositional record that has undergone a high degree of reworking over multiple sea level cycles leading to the preferential preservation of sediments associated with the most recent glacial interglacial period

link between european and north atlantic abrupt climate changes over the last glaciation 1 sub millennial timescale climate variations correlated with those in the north atlantic area are identified in the loess sequence from nussloch germany exceptionally developed over the interval between about 38 000 and 18 000 years ago the dansgaard oeschger do events 8 to 2 as well as some less pronounced warming episodes recorded in the greenland ice have their counterpart in the nussloch loess stratigraphy and in the variations of the loess grain size index gsi the north atlantic heinrich events 3 and 2 are expressed at nussloch as maxima of the gsi record the similarity of the fine variations in the nussloch loess and the greenland ice records points to an intimate link of climate changes in western europe with those in the north atlantic