fluvial response to paleo equatorial climate fluctuations during the late paleozoic ice age the maritimes basin of atlantic canada preserves a 12 km thick stratigraphic succession deposited within a low latitude predominantly continental setting during the late paleozoic this paper examines the utility of using such successions for paleoclimate analysis with specific reference to changes in fluvial style modern rivers in the subhumid and semiarid tropics preserve a suite of features that are distinct from those in humid and arid environments these features include an abundance of sedimentary structures formed under froude transcritical to supercritical flow conditions and the presence of in situ vegetation growing within the channel environment this fluvial style is indicative of prolonged low flow conditions punctuated by intense precipitation events in a strongly seasonal climatic setting fluvial channel bodies within the maritimes basin preserve a remarkably similar style compared with these modern systems suggesting that a subhumid strongly seasonal paleoclimate was the dominant imprint on parts of the preserved successions strongly seasonal deposits are concentrated within four discrete stratigraphic intervals e1 e4 ranging in duration from 2 to 6 m y these intervals are correlated across the entire basin and between basins characterized by markedly different tectonic regimes which suggests that a coherent regional climate signal is recorded intervals are separated by deposits characteristic of humid and arid river systems and the alternation between these different fluvial styles implies that several pronounced long term changes in precipitation and runoff regimes occurred during the carboniferous within the region furthermore these intervals broadly coincide with major periods of southern hemisphere glaciation which suggests that glaciation had a profound and controlling effect on paleotropical climate

transgressive dune formation along a cliffed coast at 75 ka in sardinia western mediterranean a record of sea level fall and increased windiness transgressive dunes develop frequently along strandplain coastlines however they may also form along rocky coasts dominated by cliffs and embayments two lithified transgressive dune systems developed along the cliffed alghero coast nw sardinia italy have been investigated one aeolian system forms a cliff front anchored aeolian dune accumulation the other is a valley head anchored sand ramp system optically stimulated luminescence ages indicate that both systems formed around 75 ka this period which corresponds to the beginning of mis 4 was characterized by a relatively low sea level stand 15 m below the present sea level and was preceded by a sea level highstand 1 m asl around 81 ka mis 5a our results show that this rapid sea level fall exposed an enormous amount of marine sand which was transported inland by strong northerly winds and deposited in front of cliffs or in valley heads therefore sediment supply and sea level fall seem to be critical factors controlling dune formation along rocky coasts which generate time transgressive aeolianites terra nova 00 000 000 2010

late pleistocene relic ultisols and alfisols in an alluvial fan complex in coastal tuscany detailed stratigraphic sedimentary facies and palaeosol analyses were performed on an outcrop on late quaternary deposits in the coastal area of tuscany the outcrop was selected as representative of one of the major quaternary alluvial fan complexes of central italy the ancient cecina river fan and as showing contrasting if related palaeosols the oldest relic palaeosol was identified as an ultisol representative of the most developed soil type normally found as relic soil in italy and about whose possible ages only approximate interpretations presently exist osl dating set the whole succession of sediments palaeosols and geomorphic surfaces into a firm chronological setting as a result evolution of the cecina fan complex in late pleistocene could be fully reconstructed assessment of the age of the relic ultisol produced results contrasting with current interpretations showing how such a soil type can have developed in italian conditions in a relatively short time i e since about mis 5d

aeolian dust in europe african sources and european deposits abstract a conceptual model is presented for the provenance and dispersal patterns of small dust that falls on europe generally its sources are in north africa and it is distributed across all europe several key sources can be distinguished sahelian dust comes largely from the old lake chad region this is a clay rich unimodal material saharan dust comes from the great sand sheets it contains small monomineralic particles and may have a bimodal size range three simple deposition zones can be recognised a d1a zone where sufficient dust is deposited to form a discrete soil layer not well classified as a rendoll in the extreme south of europe a d1b zone where the airborne dust simply provided a silty admixture to soil systems across middle europe and a northern zone d1c where the dust is a fugitive cloud but very occasionally forms noticeable deposits two particle formation methods can be noted particle control in sahelian dust is via the sedimentation in the original lake this gives an open structure which can be modelled using a simple monte carlo approach the open structure ensures that only small particles are produced size control is via particle packing a chipping mechanism can produce fine quartz particles from sandy deserts the aeolian energy is by and large not sufficient to cause major impact fracturing but small mineral chips can be produced in the small dust size fine and very fine silt which go into high level suspension and travel to europe and beyond the saharan material can have a wider more variable size distribution than the sahelian material the canary islands loess is largely sahelian material the cape verde islands deposits from the nearby sandy regions are saharan deposits large dust has fallen on europe and produced widespread loess deposits large dust is essentially an in continent deposit small dust comes from outside from africa

evidence of saharan dust in upper pleistocene reworked palaeosols of north west sardinia italy palaeoenvironmental implications abstract a multi disciplinary approach was followed to investigate two thick palaeosolstrata that alternate with wind blown dominated deposits developed along thealghero coast north west sardinia italy optically stimulated luminescenceages reveal that both palaeosols were developed during cooler drier periods the rst one at around 70 ka marine isotope stage 4 and the latter around 50 ka marine isotope stage 3 in contrast the pedological features indicate that thepalaeosols underwent heavy weathering processes under warm humid to sub humid conditions characteristic of the sardinian climate during the lastinterglacial stage marine isotope stage 5e to reconcile this apparent datadiscrepancy a range of sedimentological and pedological analyses wereconducted these analyses reveal that the palaeosols possess a complexhistory with accumulation and weathering occurring during marine isotopestage 5e and erosion colluviation and nal deposition taking place during thefollowing cold stages thus even if these reddish palaeosols were last formedduring the glacial period the sediments building up these strata probablyrecord the climate of the last interglacial stage marine isotope stage 5e traceelement and x ray diffraction analyses together with scanning electronmicroscope images reveal the presence of saharan dust in the parentmaterial of the palaeosols however no evidence of any far travelled africandust has been observed in the marine isotope stage 4 3 aeolian deposits it ispossible to conclude that in the west mediterranean islands saharan dustinput even if of modest magnitude is preserved preferentially in soilsaccumulated and weathered during interglacial stages keywords marine isotopic stage mediterranean osl dating trace elementgeochemistry xrd analysis sedimentology 2012 59 917 938

late pleistocene coastal evolution of san giovanni di sinis west sardinia western mediterranean abstract the upper pleistocene succession of coastal deposits outcropping at san giovanni di sinis west sardinia has been studied since the 1960s however the absence of consistent radiometric ages has allowed the production of competing stratigraphic subdivisions of these deposits with different isotopic stage ois mis attributions the succession is composed of sandy to gravelly shallow marine coastal aeolian and alluvial fan plain deposits facies analysis and log correlations show the presence of three unconformities t1 t2 t3 always overlain by shallow marine deposits cutting through the substrate alluvial fan or aeolian sediments we have collected three samples for optically stimulated luminescence osl dating at the top of each shallow marine deposit the succession is composed of four unconformity bounded units u1 u2 u3 u4 and the new osl dates indicate the presence of three different sea level highstands the first unit u1 which is composed of shallow marine to aeolian deposits and overlies transgressive surface t1 is related to a marine transgression during ois 7 186 13 ky unit 2 is composed of continental deposits and formed during ois 6 unit 3 represents ois 5 and overlies a transgressive surface t2 more precisely subunit u3a is related to ois 5e 120 10 ky eu tyrrhenian or eemian sensu strictu and is characterized by shallow marine to aeolian deposits developed during both transgressive and highstand phases the following bay deposits of subunit 3b are associated with ois 5c 100 5 ky and record a second transgressive event t3 and highstand phase occurred during the neo tyrrhenian the succession of san giovanni di sinis ends with continental deposits of unit 4 associated to a sea level fall that took place at the beginning of the last glacial phase ois 4

provenance and formation of the red palaeosol and lithified terra rossa like infillings on the island of susak a high resolution and chronological approach abstract red palaeosol rp covering the carbonate basement exposed at the bottom of the loess section and lithified terra rossa like materials situated in cavities ltr1 and karstified fissures ltr2 in cretaceous limestones were investigated by means of high resolution approach to give a systematic and deeper palaeopedological insight into reddish materials and the exposed red palaeosols on the island of susak both selected geochemical indicators of weathering al si na k al and fed fet and provenance la ce as well as detailed mineralogical analysis clearly showed differences among ltr1 ltr2 and rp respectively ltr1 and ltr2 represent erosional remains of different soils that existed on the surface of the limestone bedrock prior to the formation of the rp ltr2 has the highest ztr zircon tourmaline rutile index index and contains bauxite minerals gibbsite and boehmite clays kaolinite and mixed layer clay minerals and haematite ltr2 bears characteristics of reworked bauxitic materials mixed with other soils that existed on the surface of the carbonate basement those materials might have been mixed and transported until they were captured in the karstified fissure and subsequently interlocked with calcite veins and lithified this might have happened from the eocene age on our attempt to resolve the age of ltr2 formation more precisely using palaeomagnetic investigations did not give unambiguous results because the extremely viscous behaviour of the ltr2 samples hinders the acquisition of a stable remanent magnetisation if we exclude the secondary calcite ltr1 bears typical mineralogical and geochemical characteristics e g fed fet ratio similar to those of istrian terra rossa insoluble residues of cretaceous limestone might have been the main parent materials for the ltr1 formation while the most likely additional fluxes influencing terra rossa formation on the island of susak were aeolian dust and flysch the erosion remains ended in limestone cavities and were mixed with cm to dm sized angular and subangular limestone clasts and subsequently interlocked with calcite veins and lithified the investigated rp profile comprised the following mineral horizons bwb1 bwb2 bwb3 r the rp formed in a lithologically uniform material that dominantly presents a mixture of loess and partly remains of older soils e g rounded clay coatings not related to macrovoids that existed on the surface of the cretaceous limestone fed fet ratio in rp reflects a low degree of weathering of fe containing primary silicates therefore we can conclude that the rp does not fit a rather limited variation of selected fe oxide characteristics typical for terra rossa the investigated rp was classified independently of the overlying material the full name of the palaeosol that we classified is as follows hypereutric chromic cambisol episiltic endoloamic since no reversal of the emf was recorded in the rp we concluded that the rp formed during the brunhes epoch luminescence dating was applied to establish the age of the rp based on the acquired data we assume that the rp very likely formed during the penultimate interglacial ois7

late pleistocene carbonate aeolianites on mallorca western mediterranean a luminescence chronology abstract coastal outcrops of upper pleistocene deposits in north eastern mallorca balearic islands spain have been examined and a chronological framework established using optically stimulated luminescence osl dating the outcrops record a complex interaction between aeolian colluvial and alluvial fan deposition that result in a variable stratigraphical architecture dating and facies analysis make it possible to identify four aeolian activity episodes during mis 5c b 4 and 3 and also add to the understanding of the environmental history of north eastern mallorca over the last 100 ka the new data suggest enhanced aeolian transport and dune formation during cold climatic intervals when sea level was low sediment supply exposed marine carbonate sediment was high winter windiness was high and vegetation on coastal plains at a minimum

middle pleistocene to holocene coastal evolution of nw sardinia mediterranean sea italy abstract the middle pleistocene holocene sardinian stratigraphy has been revised to identify the roles played by sea and climate changes in controlling sedimentation the succession dated through optically stimulated luminescence quartz k feldspar and 14 c the most recent was grouped into eight major stratigraphic units mainly represented by coastal dunes shallow marine and alluvial systems these units range in age from mis 8 300 ka to mis1 6 ka little information is available for the period between mis 8 and 6 the available data however allow some comments on climate changes over the last 125 ka the last interglacial mis 5 is subdivided into five substages e a mis5e eemian is considered the climate optimum of this interglacial sea level was 4 6 m higher than today and climate conditions were warmer and more humid mis 5c is the second high stand peak sea level was about 1 5 m above the modern level and paleoclimatic and paleogeographic conditions were similar to the present during mis 4 at the beginning of the glacial phase a climatic deterioration occurred temperatures dropped by 6c relative to mis 5e in about 5 ka and sea level fell about 60 m this led to a progressive disruption of inland vegetation cover and to repeated valley slope denudation the sea level fall created the accommodation space for fan development in sheltered and cliffed areas where debris flows developed and filled almost completely the terminal parts of the narrow coastal valleys coves in wider areas however coastal dune fields developed contemporaneous presence of alluvial fan and dune systems is associated with the local morphology that could mitigate or amplify moist conditions within a generally arid environment during mis 3 several climate fluctuations occurred wet arid d o h events however the shallow sardinian shelf was continuously sufficiently exposed to become the source area of bioclastic sands these sands were blown inland and formed extensive dunefield systems dunes dominated the west coasts of sardinia under cold and relatively dry conditions in some areas these dunefield systems were eventually almost completely dismantled and reworked into water flow dominated alluvial fans by catastrophic rainfall events thus the local climate quickly switched from arid to humid conditions no record of the last glacial maximum deposits mis 2 was observed along the nw sardinian coast during the holocene transgression mis1 coastal dune systems developed and progressively migrated inland and temperature rose to reach the present day condition

loess accumulation and soil formation in central kansas united states during the past 400 000 years based on interpolation of thermoluminescence dates and the mean accumulation rate of 0 034 mm yr 1 four cycles of pedogenic caco3 accumulation are found within the loveland loess 415 325 ka 325 250 ka 250 195 ka and 195 95 ka the four caco3 peaks correspond chronologically to marine oxygen isotope stages 11 9 7 and 5 respectively the early wisconsin 95 70 ka was characterized by sand dune activity the reddish pedocomplex was formed from 70 to 35 ka under relatively warm and moist climatic conditions with a very slow rate of silt accumulation 0 016 mm yr 1 the gilman canyon pedocomplex enriched in organic matter and dated at 35 20 ka was formed under a strong physical weathering regime and a relatively high rate of silt accumulation 0 15 mm yr 1 indicating a windy relatively moist probably cool environment it developed when the laurentide ice sheet was advancing and dust content in greenland ice core was low the peoria loess was accumulated at a rate of 0 3 mm yr 1 in central kansas under cold dry conditions when the ice sheet fluctuated around its maximum position and the dust content in the greenland ice core was the highest even the warm substage around 13 ka has some corresponding evidence in the central great plains the well developed brady soil dated at 10 5 8 5 ka indicates that the early holocene was the optimal time for soil development since 20 ka the poorly weathered bignell loess might have been deposited during the altithermal period from 8 5 to 6 ka

the thermal conductivity for granite with various water contents the thermal conductivities of granite were measured under different conditions of porosity and water content to investigate the effects of the porosity and water content on the thermal conductivity for the dry samples the thermal conductivities range from 2 12 w mk for the rocks with a high porosity to 3 12 w mk for the ones with a low porosity water sorbed samples have greater thermal conductivities than dry samples of the same granite the thermal conductivities range from 2 99 w mk for granites with a high porosity to 3 62 w mk for ones with a low porosity under saturated condition

east asian summer monsoon intensity inferred from iron oxide mineralogy in the xiashu loess in southern china abstract the xiashu loess in comparison to the well studied loess sequences in the chinese loess plateau clp provides a good opportunity for studying east asian monsoon variations from a southern china perspective here we present a study of the iron oxide mineralogy of the xiashu loess using integrated geochemical and diffuse reflectance spectroscopy drs measurements as well as magnetic data our results show that the free iron oxide fe d to total iron fe t ratio fe d fe t hematite hm to goethite gt ratio hm gt and saturation isothermal remanent magnetization sirm to magnetic susceptibility ratio sirm all indicate particularly strong summer monsoons during the formation of paleosols ps5 and ps4 equivalent to marine isotope stage 13 and 11 respectively however magnetic susceptibility and fe d fe t are not consistently reliable indicators of summer monsoon intensity for the whole section our results indicate that a multi proxy approach can give a more reliable summer monsoon intensity reconstruction the summer monsoon shows a cooling trend and a declining of precipitation from 0 5 to 0 3 ma after which it becomes warmer and wetter towards the top of paleosol ps1 equivalent to mis 5 however ps1 was formed under a relatively cooler temperature and wetter soil conditions in comparison to ps5 and ps4 such supra orbital variations in the east asian summer monsoon superimposed on the effects of glacial interglacial cycles in southern china are also reflected in the 0 4 0 5 ma cycle of marine carbon isotopes in the global ocean possibly indicating a strong link between terrestrial weathering and the global carbon cycle

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

response of aeolian systems to holocene climatic and hydrologic changes on the northern margin of the sahara a high resolution record from the chott rharsa basin tunisia four millennial scale latest pleistocene to holocene climatic cycles are recorded by aeolian lacus trine strata along the southern margin of chott rharsa a playa situated within an active tectonic basin along the northern margin of the sahara desert in tunisia cycles are characterized by 1 a humid phase of dunefield stabilization and high lake levels and 2 an arid phase of playa desiccation and deflation with dunefield construction the cycles overall define a progressive drying trend and correlate well with a detailed chronology from morocco and with the sahara region in general for the latest pleistocene and early holocene climatic events appear more regional in nature for the later holocene an isolated outcrop of aeolian deposits dated at 86 ka bp argues for records of older cycles in the chott rharsa basin that were subsequently removed by long term deflation in the area

middle to late pleistocene coastal deposits of alghero northwest sardinia italy chronology and evolution the shallow marine to coastal deposits of alghero have been dated using the optically stimulated luminescence osl method and studied to define the palaeoenvironmental evolution of coastal areas in northwest sardinia dating coupled with sedimentological and stratigraphical analyses allowed the subdivision of the succession in four unconformity bounded units u2 u3a u3b u4 unit u2 of penultimate glacial stage mis 6 ca 150 ka is composed of dune deposits formed intermittently along rocky coastal areas under strong wind conditions subunit u3a is composed of cliff bounded gravelly dominated pocket beach deposits commonly highly fossiliferous and is assigned to the interglacial mis 5e ca 125 ka subunit u3b is characterized by sandy beach to coastal systems of the isotopic sub stage mis 5c ca 100 ka the unconformity between u3b and u4 marks the initiation of last glacial regression mis 5a 4 ca 77 ka during which shelf areas were exposed and small incised valleys developed along the valley flanks colluvial or sheetflood sediments were deposited and in the central part thick reddish paleosols formed valleys were eventually filled by thick aeolian dune deposits mis 4 3 indicating persistent inland sand transport around alghero coastal carbonate rich dunes preferentially formed and migrated inland during lowstand and falling stages when the climate is relatively cold vegetation is quite open winds are fairly strong and sediment supply from exposed shelf areas is high

influence of provenance weathering and sedimentary processes on the elemental ratios of the fine grained fraction of the bedload sediments from the vembanad lake and the adjoining continental shelf southwest coast of india abstract geochemical studies comprising twelve major elements and twenty four trace elements including the rare earth elements ree have been carried out on the concentrations normalized to the average upper continental crust ucc show that the sediments studied are depleted in rb k ba ta hf na and ca and enriched in cs u th rees sc fe co and cr ucc normalized patterns are strikingly similar for all the three sediment types probably because of efficient mixing of sedimentary material during weathering transport and deposition the depletion of na k ca and ba in sediments relative to ucc could be attributed to their mobility during weathering the depletion of ta and hf and enrichment of th ree and sc are probably related to provenance characteristics and enrichment of u is attributed to oxidation reduction processes shale normalized ree values reveal steep hree patterns tbsample tbshale ybsample ybshale lasample lashale smsample smshale and flat lree patterns the shale normalized patterns for all the three types of sediments are remarkably similar with variations in the magnitude of lree enrichment lan ybn varies between 1 72 to 2 57 times that of paas lree enrichment and steep hree patterns are attributed to felsic source rock characteristics other geochemical characteristics such as high la th and low la sc and th sc ratios compared to ucc also support a felsic provenance eu eu values for all the three types are little more than 1 which is also a characteristic feature of archean crust furthermore data plotted on discrimination diagrams of la th vs hf and la th sc cluster closer to granite and away from basalt and komatiite and are consistent with source rock geology geochemical data have also helped in ascertaining the weathering trends the chemical index of alteration cia has been used to quantify the degree of weathering cia values range between 81 and 94 on a scale of 40 100 indicating a high degree of alteration fluvial sediments seem to be more altered on an a cn k diagram the data fall closer to the compositional fields of highly weathered minerals kaolinite gibbsite and chlorite a high degree of weathering is also indicated by other plots such as k2o fe2o3 al2o3 and log k vs log rb the geochemical data are consistent with the studies on clay mineralogy higher kaolinite carried out by other authors on the sediments of the same area secondary processes seem to affect other geochemical discriminants such as co cr ni and u as revealed by plots of 1 la sc vs co th and 2 th hf co and co th cr th ratios and makes them unsuitable for determining provenance and tectonic setting

rare earth elements of aeolian deposits in northern china and their implications for determining the provenance of dust storms in beijing this paper contributes to a better understanding of the source of dust storms in northern china and the relationship between these sources and other aeolian sediments in this region sediment samples in potential source areas were collected from the hunshandake sandy land heaven desert the loess deposits of the bashang area the mountainous basins and valleys north of beijing and from the badain jaran desert and hulunbaier sandy land fig 1 dust samples were collected in beijing during two dust storms in march 2002 and april 2006 the laboratory methods used in this study included measurements of abundance of trace elements in particular the rare earth elements rees mineral assemblages and grain size the ree contents eu and ce anomalies show clear differences between various deposits provenance is considered to be the key factor influencing ree patterns in the study areas the ree abundances and patterns indicate that the aeolian sand north of beijing such as in the heaven desert is mainly of local origin rather than from desert encroachment from the north the mineral grains carried in dust storms however are highly mixed and may come partly from local sources but mainly from distant desert regions in western china

geochronology for some key sites along the coast of sardinia italy recent stratigraphic surveys and facies analyses have questioned long held interpretations of the development and furthermore the age of quaternary sediments along the coast of sardinia the matter of debate is whether the investigated sediments were deposited during the late wurmian and holocene or during marine isotope stage mis 5 and older stages optically stimulated luminescence standard blue optically stimulated luminescence osl post infrared ir pulsed blue osl and post ir infrared stimulated luminescence irsl dating was applied to shallow marine and aeolian deposits as well as radiocarbon dating to bulk organic material in palaeosols radiocarbon dates suggest sedimentation during the late wurmian and holocene whilst the luminescence results for both quartz and potassium feldspar indicate a depositional age for most of the investigated sites prior to and during mis 5 from a geochronological point of view the luminescence ages are considered reliable because they passed all quality tests furthermore there is good agreement of two dosimeters with different bleaching and luminescence properties the radiocarbon ages might suffer from underestimation due to some contamination with young carbon which however cannot be large enough to yield such young ages

tyrrhenian coastal deposits from sardinia italy a petrographic record of high sea levels and shifting climate belts during the last interglacial isotopic substage 5e abstract detailed petrographic and sedimentological analysis of tyrrhenian coastal deposits from four sites in sardinia provides new data about climate and sea level changes during the early part of the last interglacial isotopic substage 5e and shows that facies analysis is not only useful for the identification of ancient depositional environments but also represents a powerful tool for evaluating past climatic conditions and sea level forcing mechanisms two shallowing upward sequences sensu ward w c brady m j 1979 strandline sedimentation of carbonate grainstones upper pleistocene yucatan peninsula mexico am assoc pet geol bull 63 362 369 commonly separated by an erosion surface and displaying complex geometric relationships occur above modern sea level at several locations along the shorelines of sardinia these sequences include upper shoreface to backshore deposits and were formed during separate sea level highstands attributed to isotopic substage 5e our recent revision of these deposits indicates that each sequence presents distinctive petrographic characteristics the older succession essentially contains mixed calcarenites rich in quartz grains and lithic fragments whereas the younger sediments are dominated by carbonate bioclasts such as red algae coral and mollusk fragments both units apparently accumulated in a similar depositional setting but during different climatic regimes the petrography of the lower unit reflects a temperate humid period characterized by increased weathering and continental erosion whereas the composition of the upper one suggests a dryer and possibly warmer climate favoring active carbonate production the disparity in petrographic composition between sequences probably records the migration of atmospheric circulation cells i e a shift of climate belts before and after the 128 ka insolation maximum our climatic data are coherent with the calculated insolation curves for isotopic substage 5e and thus support the milankovitch hypothesis for the origin of pleistocene climates in contrast our sedimentological data clearly show the occurrence of two distinctive highstands of sea level during this time period which does not agree with the hypothesis it follows that the relation between orbitally induced insolation variations climate and sea level is not necessarily straightforward

climatic change during the lower carboniferous in euramerica based on multivariate statistical analysis of palynological data abstract lower carboniferous palynological assemblages show marked differences between north and south euramerica in order to assess these regional differences multivariate statistical analysis has been applied to percentage frequency data from palynological assemblages from twenty different localities of euramerica the principal components resulting have been related to climate sensitive rocks such as coal and evaporites this relationship has been interpreted in terms of humidity curves and climatic zones four climatic zones have been recognized a dry a moderately humid and a humid zone the latter zone may be subdivided into a humid and a very humid zone during the lower carboniferous the humid climatic zone and the related palaeoclimatic equator shifts southwards however the very humid conditions present in the uppermost tournaisian to middle visean of spitsbergen have not yet been reached in the lower namurian of western europe and the u s a the southward shift of the palaeoclimatic equator has been interpreted in terms of a northward drift of the euramerican continent the palaeomagnetic evidence available for this northward drift is briefly discussed

conodont biostratigraphy of the codroy group lower carboniferous southwestern newfoundland canada four stratigraphically successive conodont assemblage zones have been recognized in the lower carboniferous codroy group of southwestern newfoundland the diplognathodus zone is confined to the basal ship cove limestone and to a highly fossiliferous correlative at aguathuna the overlying taphrognathus zone occurs in carbonates in the stratigraphic interval above the sequence of massive sulphates and thick clastics the taphrognathus zone as well as the successive cavusgnathus zone has been recognized on fischells brook as well as in the complex section south of codroy the highest conodont zone the gnathodus zone has been recognized in the crabbes jeffreys limestone of the st george s bay area and from south of codroy the discovery of conodonts of the diplognathodus zone in marine strata that are stratigraphie and lithologie correlatives of the macumber and the gays river formations of nova scotia now makes it possible to microfaunally characterize the a subzone a macrofaunal subzone established

soil stratigraphy and quaternary caliche in the misis area of the adana basin southern turkey abstract a section at kizildere in the misis adana basin of turkey reveals relations among mature massive caliche calcrete and paleosolic immature caliche and the tertiary clay the handere formation and colluvial deposits it also defines a gradational sequence from unweathered tertiary clay deposits to massive caliches from older to younger the section comprises tertiary clays paleosolic caliche colluvial material massive caliche and lenticular caliche the two massive caliche beds have similar assemblages of carbonate minerals whereas the paleosolic caliche contains more clay minerals and most probably represents an earlier stage of massive caliche formation the variability of types of calcite the quantity and crystallisation state of palygroskite and the presence of kaolinite and degraded smectite all support the view that the massive caliche is the end product of a degradation sequence from the tertiary clay deposit to paleosolic caliche and the lenticular caliche is the well known petrocalcic horizon

geochemical evidence of saharan dust parent material for soils developed on quaternary limestones of caribbean and western atlantic islands abstract most previous workers have regarded the insoluble residues of high purity quaternary limestones coral reefs and oolites as the most important parent material for well developed clay rich soils on caribbean and western atlantic islands but this genetic mechanism requires unreasonable amounts of limestone solution in quaternary time other possible parent materials from external sources are volcanic ash from the lesser antilles island arc and saharan dust carried across the atlantic ocean on the northeast trade winds soils on quaternary coral terraces and carbonate eolianites on barbados jamaica the florida keys united states and new providence island bahamas were studied to determine which if either external source was important caribbean volcanic ashes and saharan dust can be clearly distinguished using ratios of relatively immobile elements al 2 o 3 tio 2 ti y ti zr and ti th comparison of these ratios in 25 soils where estimated ages range from 125 000 to about 870 000 yr shows that saharan dust is the most important parent material for soils on all islands these results indicate that the northeast trade winds have been an important component of the regional climatology for much of the quaterary saharan dust may also be an important parent material for caribbean island bauxites of much greater age

stratigraphic significance of upper devonian and lower carboniferous miospores from the type area of the horton group nova scotia late devonian late famennian miospores have been found in the lowermost 7 3 m of the horton group on harding brook in the type area windsor subbasin nova scotia below tournaisian miospores of the emphanisporites rotatus indotriradites explanatus zone extending the age of the horton group in the type area down into the latest devonian shows that the lowest beds of the 1000 m thick group are coeval with latest devonian rocks elsewhere in the maritimes basin that have been excluded from the horton group by some authors evidence presented here favours the argument that late devonian rocks lithologically similar to the horton group deposited on the acadian unconformity should be included in that group miospore evidence indicates a minimum age of about 355 ma for exhumation of the northeastern part of the south mountain batholith

geochemical and mineralogical evidence for sahara and sahel dust additions to quaternary soils on lanzarote eastern canary islands spain africa is the most important source of dust in the world today and dust storms are frequent on the nearby canary islands previous workers have inferred that the sahara is the most important source of dust to canary islands soils with little contribution from the sahel region soils overlying a late quaternary basalt flow on lanzarote canary islands contain in addition to volcanic minerals quartz and mica exotic to the island s bedrock kaolinite in the soils also likely has an exotic origin trace element geochemistry shows that the soils are derived from varying proportions of locally derived basalt and african dust major element geochemistry clay mineralogy and interpretation of satellite imagery suggest that dust additions to the canary islands come not only from the sahara desert but also from the sahel region

luminescence dating of interglacial coastal depositional systems recent developments and future avenues of research abstract luminescence dating offers new opportunities to explore the evolution of quaternary marine coastal facies and landforms this review highlights the main advances in luminescence geochronology of interglacial coastal sediments through the analysis of 547 luminescence ages most of which were published during the last decade the majority of these reported luminescence investigations have been carried out along passive margin coasts since the turn of the century the discovery of a normalization procedure known as single aliquot regeneration sar has drastically reduced data scatter and improved precision with the consequence that quartz sar optically stimulated luminescence osl has become the dating protocol of choice for the last interglacial lig period a more complex technique known as thermally transferred osl tt osl is presumably proposed for dating older interglacials of the mid pleistocene and beyond feldspar luminescence is increasingly being applied to dating pleistocene sea level high stands due to a much higher dose saturation level than quartz osl the use of feldspar irsl infrared stimulated luminescence is limited by the occurrence of variable but ubiquitous anomalous fading af following the advent of af correction methods several middle pleistocene sites have been amenable to dating albeit with significant related uncertainties recently new protocols involving the measurement of post ir irsl at elevated temperatures have yielded relatively coherent ages for interglacial sediments up to ca 300 ka quartz osl tt osl af corrected irsl and post ir irsl ages are generally correlated with periods of sea level high stands a few ages are reported from the early and middle part of the middle pleistocene as mis11 9 and more commonly mis7 high stands are documented in strongly uplifting active margin coasts however by far the most obvious age peak corresponds to the end of the lig the mis5e shoreline is probably the most studied and luminescence dated coastal feature of all as the chronology of the sea level markers is crucial to assess global eustatic sea level variations through the course of the last interglacial nevertheless the observed abundance of young 100 120 ka luminescence ages for presumed mis5e sediments may underline methodological issues and or reflect the higher preservation potential of late regressive sequences on the other hand the occurrence of geographically distant reports of mis5a high stand might reflect a true eustatic origin for this event age analysis supports the impression of general reliability of luminescence for the timing of former sea level high stands there is a clear need to address issues in dose rate variability in the phenomenology of fading in feldspar and in the behaviour of luminescence growth with dose both in laboratory and natural conditions these could be addressed and properly evaluated by dating different minerals as multiple or single grains with consequent variable internal dose rates more robust practices in the application of luminescence dating techniques could eventually constrain the age uncertainties to no better than 2 3 therefore the strength of luminescence as a dating tool is more in terms of its extended age range and the ubiquity of datable material

buried palaeosols of nw sardinia italy as archives of the late quaternary climatic fluctuations abstract a multi disciplinary approach was performed to investigate two compound geosols included between wind blown deposits at the top and interglacial mis 5 beach sediments at the bottom located along the alghero coast north western sardinia italy a sedimentological and morphological study was carried out on the profile in the field and samples collected on the main pedomembers were subjected to several laboratory analyses consisting of physical and chemical determinations on bulk samples mineralogy xrd micromorphology on undisturbed samples thin section sem and edax micro probe analyses dating was performed by means of optically stimulated luminescence osl the studied geosols show the evidence of a complex pedosedimentary evolution around 80 to 70 ka the lower geosol underwent weathering and clay illuviation wet and warm conditions followed by calcification recalcification processes dry contrasted and finally by strong bioturbation around 70 ka the onset of the glacial period mis 4 is marked by the deposition of a sand dune capping the lower geosol these results indicate that the coastal area of the central mediterranean kept the relatively warm conditions typical of the interglacial climate for most of the early wurm and reached cold conditions only at about 70 ka possibly in relation to the rapid cooling of the heinrich event h7 the upper geosol developed on colluvial material including abundant pedorelicts and reddish earth material deposited around 50 ka before being buried by aeolian sand around 43 ka this deposit underwent pedogenesis phases possibly associated to middle wurm interstadial events indicating that in the study area these events were intense enough to influence pedogenesis

estimation of thermal conductivity from the mineral composition influence of fabric and anisotropy measured values of thermal conductivity from crystalline rocks are compared with values calculated from the mineral content using the layered model first thermal conductivity is estimated using data based on quasi isotropic mixtures of fragments or powder second the approach is applied on core data considering the anisotropy of some rock forming minerals the numerical value of estimated thermal conductivity is controlled by the quartz content sheet silicates control anisotropy and fabric in gneisses and their thermal consequences if imformation about the fabric of the rock is available the anisotropy of minerals can be considered in a layered model and this improves the estimation of thermal conductivity from mineral contents

sedimentology of the lower serpukhovian upper mississippian mabou group in the cumberland basin of eastern canada tectonic halokinetic and climatic implications the visean serpukhovian transition in atlantic canada was marked by a general humidification of the climate as the region drifted towards equatorial latitudes it also corresponds to a time when ice volume was increasing on gondwana which marked the end of mississippian marine incursions in the region glacioeustatic fluctuations of greater magnitude are thought to have increased the response of the regional climate to third order cyclicity from orbital forcing in the cumberland basin fluvial grey beds of the lower serpukhovian shepody formation were deposited in sub humid conditions during highstands whereas red playa deposits of the same unit were deposited under semi arid conditions during lowstands basin reconstruction suggests that this unit was sourced from the fault bounded cobequid and caledonia highlands and deposited in two separate salt withdrawal minibasins this fluvial system was seemingly discharging to the north into the broad lake that deposited the contemporaneous hastings formation a disconformity separates the shepody formation from mid serpukhovian red beds of the claremont formation and is tentatively associated with another increase in ice volume on gondwana followed by a recrudescence of fault activity and basin subsidence a prolonged time of aridity floral crisis non deposition deep weathering and karstification in late serpukhovian to early bashkirian times is contemporaneous with abundant glacial deposits in higher latitudes suggesting that globally low sea levels may have been at play in creating a situation of greater continentality in the study area

magnetic polarity stratigraphy and palynostratigraphy of the mississippian pennsylvanian boundary interval in eastern north america and the age of the beginning of the kiaman magnetic polarity data from the maritimes basin in eastern canada reveal patterns of magnetic reversal through 17 m y of late mississippian and early pennsylvanian time we collected samples from three sections on cape breton island a fourth that extends a section studied previously and a fifth from a deep cored well on prince edward island we compared the polarity data from these sections to previous results from lower parts of the joggins section of eastern canada all sections are constrained by new palynological data and collectively span the late mississippian brigantian pendleian and much of the arnsbergian substages a major unconformity at the pennsylvanian mississippian boundary makes correlation difficult the late mississippian arnsbergian substage is dominated by normal polarity whereas the pendleian and brigantian are characterized by normal and reversed polarity intervals in about equal proportions in the united states the mississippian pennsylvanian boundary is a major hiatus that juxtaposes strata of early pennsylvanian age on mississippian strata ranging in age from brigantian to mid to late arnsbergian data for the mauch chunk formation in the united states provide polarity reversal patterns for correlative sequences in the central appalachian basin field mapping and magnetic polarity data show closely comparable mississippian pennsylvanian relationships in the maritimes basin more than 1500 km northeast from the u s sections the eustatic event that coincides with the mississippian pennsylvanian boundary unconformity is late arnsbergian to yeadonian in both the central appalachians and maritime basins basal pennsylvanian strata of yeadonian to langsettian age on cape breton island reveal normal paleomagnetic polarity through several hundred meters of section these strata are overlain by a thick section showing only reversed polarity we believe that this polarity boundary is the base of the kiaman an early langsettian position ca 318 ma for the base kiaman superchron is indicated by these new data in eastern nova scotia and new brunswick the sedimentary rocks just above the unconformity are of reversed polarity it is clear that the sedimentation in the two areas is affected by the unconformity and no magnetic or palynological correlation is possible above the unconformity only saetosa zone sediments are present

loess in italy genesis characteristics and occurrence abstract there is currently a renewed interest in loess genesis and occurrence in italy well known loess profiles in northern italy have been re examined and previously unknown loess deposits in central and southern italy have been reported this work combines a meta analysis of published data with new data presented here for the first time to provide the state of the art on the spatial distribution characteristics genesis and deposition ages of loess in italy a database of 98 soil horizons from 91 soil profiles was created and made available it stores information on soils formed from loess or containing layers that show admixture of loess soil data include the source of information the topographic geomorphological and geological setting kind of parent material and land use main soil horizon properties as described in the field soil classification particle size distribution and chemical data loess is reported from almost all regions of italy it is generally pedogenized throughout the entire loess body and forms the parent material of deep and complex soil profiles the thickness of the loess deposits varies from a few decimeters to a few meters pedogenesis and local reworking partially change the original loess characteristics in this study we propose a set of parameters that help recognizing loess in soils particle size distribution and sorting geomorphological setting pedostratigraphic position shape of the grains under optical and scanning electron microscope sem and soil micromorphological characteristics the ages of the loess deposits range between 70 ka bp and 18 ka bp there are also a number of samples that have been dated to the holocene the meta analysis suggests that climate is not the only driver of loess deposition in italy geomorphological instability and human disturbance as well as the influence of saharan dust most likely played major roles too this study demonstrates that loess is much more widespread in italy than previously estimated yet further research on the spatial and temporal distribution of loess deposition across the mediterranean region is needed to better understand its genesis sources and trajectories periods of enhanced loess formation and the role of loess deposits in ecosystem functioning and resilience

age and significance of late pleistocene lithophyllum byssoides intertidal algal ridge nw sardinia italy abstract intertidal coralline red algal build ups lithophyllum byssoides rims or ridges are considered precise sea level markers and mostly used for holocene sea level history several well preserved patches of relict red algal ridges crop out along the north west sardinian coast mediterranean sea italy and have great potential in reconstructing the late pleistocene sea level history of the western mediterranean the aim of this paper is to determine the sedimentary characteristics of the relict lithophyllum byssoides build ups cropping out along the sardinian nw coast and to demonstrate how these can be used as past sea level indicators to establish a chronological framework for these deposits luminescence dating both quartz osl and k feldspar pirir290 has been applied and allows for the lithophyllum byssoides ridge formation to be assigned to marine isotopic stage mis 5e 132 112 ka the studied relict ridges confirmed that mis 5e sea level was at least at 4 m above present well matching the widely accepted last interglacial global sea level curves hence fossil lithophyllum byssoides ridges can be used as stratigraphic and chronologic indicators of late pleistocene sea level moreover the study has underlined that lithophyllum byssoides may grow 1 in sheltered places along high cliffy coasts forming bench like structures and 2 in high energy environments on wave cut platforms around fallen blocks or potholes first as isolated mounds and then merging to form reef like structures

palynostratigraphy and lithostratigraphy of carboniferous upper codroy group and barachois group southwestern newfoundland a new zone the reticulatisporites carnosus assemblage zone of late pendleian to arnsbergian age is proposed for miospore assemblages in the searston formation of the barachois group and in unnamed coal bearing strata in higher portions of the group the beds containing the zone can be correlated with those in other parts of the euramerican floral province in western europe including the north sea where the climate was semi humid temporal relationships suggested by these new biostratigraphic data indicate that a reassessment of the regional lithostratigraphy of southwestern newfoundland is required the overfall brook member of the robinsons river formation formerly assigned with its correlative the brow pond lentil to the codroy group is here identified as a basal unit of the searston formation it lies unconformably on codroy group beds of brigantian age elsewhere the basal beds of the barachois group lie unconformably on pre carboniferous rocks the barachois group in the codroy and st george s bay lowlands correlates with the humber falls and howley formations of the deer lake subbasin of western newfoundland and with the pomquet formation of the mabou group nova scotia the pendleian arnsbergian coal bearing strata high in the undivided barachois group predate the post arnsbergian major floral crisis and with their correlatives represent the youngest known rock units of mississippian age in atlantic canada they are significantly older than the pennsylvanian coal measures of moscovian bolsovian age in a small outlier near stephenville and we recommend the latter be removed from the barachois group

first evidence for onshore marine isotope stage 3 aeolianite formation on the southern cape coastline of south africa abstract the southern cape coast of south africa boasts an impressive suite of plio pleistocene aeolian dune deposits aeolianite previous research has shown that in this region onshore dune accumulation was generally focused around interglacial sea level highstands with the locus of coastal dune accumulation shifting onto the adjacent continental shelf during glacial sea level lowstands here using new luminescence dating results we present the first evidence for preserved onshore glacial age dunes specifically on the robberg peninsula a rocky headland 28 km east of knysna two phases of aeolianite formation are identified corresponding to early 45 60 ka and late 35 30 ka marine isotope stage mis 3 subsequently during the holocene all substantive dune accumulation occurred between 10 2 and 7 0 ka forming cliff fronting dunes and filling the limited accommodation space on the headland including an archaeological rock shelter combining these ages with bathymetric data we infer that this distinct onshore glacial age aeolianite record reflects 1 restricted accommodation space during sea level highstands 2 a regional narrowing of the continental shelf and 3 liberation of sediments lying on a prominent 45 to 60 m offshore terrace which would have been exposed during mis 3 this demonstrates that despite broad regional scale trends in the timing of coastal aeolian activity driven by commonalities in relative sea level trends and climate distinct local variations in late quaternary coastal evolution can be identified this is ascribed to local controls on preservation accommodation space and sediment supply shoreline position and antecedent offshore sediment supplies such findings may have wider implications for interpretations of site context resource availability at several notable coastal archaeological sites and more broadly suggest that local offshore or onshore geologic contexts can at times assume greater influence on a preserved coastal aeolianite record than the regional scale trends in sea level and climate

provenance of aeolian sediment in the taklamakan desert of western china inferred from ree and major elemental data abstract to identify the provenance of aeolian deposits in the extensive dune field in the taklamakan desert is of great importance for understanding the formation of this the largest sand sea in china the opinions from earlier studies are quite dipolar and are as follows a local origin of the dune sands in different parts of the desert on the basis of various heavy mineral assemblages and b strong homogenization of the sands in the entire taklamakan on the basis of geochemical data from whole rock samples by separately examining the ree characteristics and major elemental composition in coarse and fine fractions of the samples from aeolian deposits this paper provides new data for interpreting sources of aeolian deposits in the taklamakan the sampling sites are distributed in four different fluvial systems i e the areas of the keriya river niya river and cele river in the southern part and the northern margin near the tarim river fig 1 our results show that there are some significant differences in concentrations of trace elements and in ree features between the coarse and the fine fractions of the aeolian sediment the major elemental and ree data suggest that the coarser sand is different from area to area in the desert rather than a homogenization of the entire basin the fine fractions mainly silts are more homogenized the regional difference of coarse fractions in the study areas is consistent with the fluvial and wind systems in the basin this confirms that the sands are often mixed between the northern and southern parts but there is much less mixing along the east west direction it should be emphasized that not only glacial and aeolian processes but also fluvial and lacustrine processes have jointly contributed to the formation of the huge sand sea in addition little variation is found between old and young sands in two sediment sequences in the central part of the desert indicating consistency of sand sources in a given site during the last 40 ka

investigations into the potential effects of pedoturbation on luminescence dating much effort has been focussed on understanding the luminescence properties of natural minerals to achieve a reliable accurate and precise dating technique however some field related aspects such as the influence or effect of post depositional disturbance on luminescence dates are as yet underexplored in the case of pedoturbation depending on its intensity the rate of sedimentation and unit thicknesses potentially the whole sedimentary record at a site can be affected this may lead to distorted osl chronologies and erroneous sediment burial ages pedoturbation can result in sediment mixing and or exhumation that affect luminescence both at the bulk and single grain level effects of these two principle processes on luminescence ages are examined using standard multigrain and single grain protocols high resolution sampling of surface gopher mounds was used to determine the efficiency of bio exhumation in resetting luminescence signal results show this is an inefficient mechanism for onsite sediment bleaching the effects on luminescence signal of bio mixing were explored by comparing a sample collected from within a krotovina infilled burrow to an adjacent undisturbed sample results show the difficulties in identifying pedoturbated samples at the single aliquot level and the possible inaccuracies in using the lowest palaeodose values to calculate osl ages where pedoturbation of samples is suspected use of probability plots of palaeodoses data is recommended from these plots it is proposed that only data falling within a normal distribution centred on the peak probability be used to calculated osl ages and to mitigate problems arising from pedoturbation

seasonal chemical and mineralogical variability of atmospheric particles in the coastal region of the northeast mediterranean abstract a time serial analysis of atmospheric particles collected since 1990 at a coastal site bordering the northeastern mediterranean sea shows that the collected samples display seasonal patterns in both concentration and color the 1990 91 and 1992 collections yield an annualised average of around 0 5 g day dust loading reducing to around 0 3 g day when the sea salt contribution is excluded the highest concentrations of atmospheric particles of continental origin for both natural e g fe mn and anthropogenic e g cd pb materials are observed between april and october and this variability is inversely related to the frequency and the amount of rainfall sea salt aerosol na contents do not follow this pattern but are related to local wind speeds trace elements in the dusts also display seasonal variations in enrichment factors ef with respect to average elemental abundances in crustal rocks the non enriched crustal elements appear to be indicators of long distance supply while the strongly enriched anthropogenic and moderately enriched suites of elements represents inputs from local or anomalous sources the similar morphology of quartz and calcite grains and the uniformity of the clay mineral assemblages in samples collected over a two year period strongly indicate a common source for the bulk of the atmospheric particles the dominant clay types palygorskite and smectite document a desertic source areas

holocene saharan dust deposition on the cape verde islands sedimentological and nd sr isotopic evidence holocene aeolian silts deposited on the cape verde islands provide information about the origin of african palaeodusts that have fallen on the north eastern atlantic ocean over the last 10 000 years sedimentological composition indicates that most of these aeolian silts are unquestionably of continental origin their sr and nd isotopic composition identifies a saharan origin suggesting transport by harmattan winds we estimate that saharan dust comprises 75 95 of material in these holocene silts the rest coming from the weathering of local basaltic bedrock

geochemistry of rare earth elements in the mainstream of the yangtze river china abstract water suspended matter and sediment samples were taken from 8 locations along the yangtze river in 1992 the concentration and speciation exchangeable bound to carbonates bound to fe mn oxides bound to organic matter and residual forms of rare earth elements la ce nd sm eu tb yb and lu were determined by instrumental neutron activation analysis inaa the contents of the soluble fraction of rees in the river are low and rees mainly reside in particulate form in the particles the chondrite normalized distribution patterns show significant lree enrichment and eu depletion while normalized to shales both sediments and suspended matter samples show relative lree enrichment and hree depletion rees are relatively enriched in fine grained fractions of the sediments the speciation characteristics of rees in the sediments and suspended matter are very similar the amount of the five forms follows the order residual bound to organic matter bound to fe mn oxides bound to carbonates exchangeable about 65 to 85 of rees in the particles exist in the residual form and the exchangeable form is very low high proportions of residual rees reveal that rees in sediments and suspended matter are controlled by their abundances in the earth s crust carbonate fe mn oxide and organic fractions of rees in sediments account for 2 4 6 9 5 2 11 1 and 7 3 14 0 of the total contents respectively they are similar to those in the suspended matter this shows that carbonates fe mn oxides and organic matter play important roles during the particle water interaction processes by normalization to shales the 3 forms of rees follow convex shapes according to atomic number with middle ree sm eu and tb enrichment while light ree and heavy ree are depleted

insect trace fossils in pleistocene deposits from the pityusic islands balearic archipelago western mediterranean ichnotaxonomy and palaeoenvironmental significance abstract insect trace fossils attributable to the celliforma ichnofacies rebuffoichnus casamiquelai and palmiraichnus castellanosi are recorded from the pleistocene deposits of nine sites from the pityusic islands these deposits characterized by aeolian and colluvial strata interbedded with two types of palaeosols with a high amount of trace fossils show a strong relationship with environmental changes occurred during the pleistocene the celliforma ichnofacies is typical of well drained palaeosols with low vegetation indicating semiarid to sub humid conditions according to the abundance of ichnospecies in each type of palaeosol palmiraichnus castellanosi indicates that bees preferred to nest in wetter conditions whereas rebuffoichnus casamiquelai indicates that coleopterans could live under drier conditions even in this case when its abundance is relatively high within periods with increased rainfall

the role of african dust in the formation of quaternary soils on mallorca spain and implications for the genesis of red mediterranean soils abstract african dust additions explain the origin of terra rossa soils that are common on the carbonate platform island of mallorca spain mineralogical and geochemical analyses indicate that quaternary carbonate eolianites on mallorca have a very high purity usually composed of more than 90 carbonate minerals calcite dolomite and aragonite in contrast terra rossa soils developed on these eolianites have lower carbonate contents and contain higher concentrations of quartz and other silicates analyses of immobile trace elements indicate that the non carbonate fractions of the eolianites have distinctive zr hf la yb cr sc and th ta values that differ from the superjacent terra rossa soils these observations indicate that even if sufficient dissolution of the eolianite had taken place to create the soils by residual accumulation immobile element ratios in the soils require an external source however zr hf la yb cr sc and th ta values in the soils fall within the range of values for these element ratios in african dust collected on barbados and mainland spain we conclude that the silicate fractions of terra rossa soils on mallorca are derived mainly though not wholly from far traveled african dust and this process may explain the origin of other terra rossa soils found in southern europe

abrupt temperature changes in the western mediterranean over the past 250 000 years a continuous high resolution western mediterranean sea surface temperature sst alkenone record spanning the past 250 000 years shows that abrupt changes were more common at warming than at cooling during marine isotope stage mis 6 sst oscillated following a stadial interstadial pattern but at lower intensities and rates of change than in the dansgaard oeschger events of mis 3 some of the most prominent events occurred over miss 5 and 7 after prolonged warm periods of high stability climate during the whole period was predominantly maintained in interglacial interstadial conditions whereas the duration of stadials was much shorter

dune phases as time transgressive phenomena manawatu new zealand abstract new zealand s most extensive holocene dunefield is situated in the manawatu and adjoining regions evidence collected from the area including 25 radiocarbon dates suggests that the dunefield developed in phases with the first probably initiated at the coast earlier than 6000 years ago the first phase may have ceased near the coastline around 4500 years ago but dunes continued to migrate until they reached 16 km inland ca 1600 years ago about 3500 years ago dunes again began migrating inland from the coast with some still active 400 years ago the time transgressive nature of transgressive dune deposits and the possible causes of the dune phases are discussed

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

eolian dust deposition on the giara di gesturi basalt plateau sardinia mineralogical study of samples from depression fills on an isolated basalt plateau in central sardinia showed that although the basalt is free of quartz and mica fair amounts of these minerals occur in the finer fractions results from x ray analyses of silt fractions and morphoscopical analyses of sand fractions indicate that the bulk of the quartz and mica is of eolian origin the eolian quartz is predominantly of medium and coarse silt size and in the upper 10 cm of the depression fills constitutes about 20 per cent of the soil mass approx 20 kg m2 eolian mica is present in smaller amounts and is of medium silt or smaller size the provenance of the eolian material could not be established with certainty although a local origin can be excluded

airborne dust transport to the eastern pacific ocean off southern california evidence from san clemente island 1 islands are natural dust traps and san clemente island california is a good example soils on marine terraces cut into miocene andesite on this island are clay rich vertisols or alfisols with vertic properties these soils are overlain by silt rich mantles 5 20 cm thick that contrast sharply with the underlying clay rich subsoils the silt mantles have a mineralogy that is distinct from the island bedrock silt mantles are rich in quartz which is rare in the island andesite the clay fraction of the silt mantles is dominated by mica also absent from local andesite and contrasts with the subsoils dominated by smectite ternary plots of immobile trace elements sc th la and ta nd cr show that the island andesite has a composition intermediate between average upper continental crust and average oceanic crust in contrast the silt and to a lesser extent clay fractions of the silt mantles have compositions closer to average upper continental crust the silt mantles have particle size distributions similar to loess and mojave desert dust but are coarser than long range transported asian dust we infer from these observations that the silt mantles are derived from airborne dust from the north american mainland probably river valleys in the coastal mountains of southern california and or the mojave desert although average winds are from the northwest in coastal california easterly winds occur numerous times of the year when santa ana conditions prevail caused by a high pressure cell centered over the great basin examination of satellite imagery shows that easterly santa ana winds carry abundant dust to the eastern pacific ocean and the california channel islands airborne dust from mainland north america may be an important component of the offshore sediment budget in the easternmost pacific ocean a finding of potential biogeochemical and climatic significance

optically stimulated luminescence dating as a tool for calculating sedimentation rates in chinese loess comparisons with grain size records understanding loess sedimentation rates is crucial for constraining past atmospheric dust dynamics regional climatic change and local depositional environments however the derivation of loess sedimentation rates is complicated by the lack of available methods for independent calculation this limits interpretation of the environmental changes revealed by the loess record in particular while the quaternary neogene chinese loess and red clay sequences have the potential to provide detailed records of past sedimentation and climate change there is great uncertainty concerning i the influences on sediment grain size and accumulation and ii their relationship through time and across the depositional region this uncertainty has led to the widespread use of assumptions concerning the relationship between sedimentation rate and grain size in order to derive age models and climate reconstructions to address this uncertainty detailed independent age models based on optically stimulated luminescence dating undertaken at 10 to 40 cm intervals at five sections across the loess plateau in china have been used to calculate sedimentation rates and make comparisons with grain size changes over the late pleistocene and holocene the results demonstrate that sedimentation rates are site specific extremely variable over millennial timescales and that this variation is often not reflected in grain size changes in the central part of the loess plateau the relationship between grain size and sedimentation rate appears most complex suggesting an interplay between local conditions at source and sink and a changing emplacement mechanism this observation further undermines the common use of loess sedimentation age models that rely on a derived relationship between grain size and sedimentation rate from a type section the results also highlight the difficulty in assigning specific environmental causes to sedimentation rate changes and to a lesser extent grain size shifts

post ir irsl290 dating of k rich feldspar sand grains in a wind dominated system on sardinia abstract the reliability of a post ir elevated temperature irsl 290 c pirir290 is tested on wind blown sand sized 180 250 m k rich feldspar grains the pirir290 ages were compared with quartz sar osl data other independent age controls and historical information three study areas along the coast of sardinia italy were selected the south alghero coast the bue marino cave e sardinia and the alghero bay nw sardinia along the south alghero coastline a thick dunefield system is widely recognised in the literature to represent the beginning of the last glacial phase post 80 ka from a single block sand sized grains for quartz sar osl and k feldspar pirir dating were collected the natural quartz sar osl sample lies below the saturation limit of the dose response curve de

correlation of mineralogical and textural characteristics with engineering properties of selected granitic rocks from turkey abstract granitic rocks show a variety of engineering properties that may affect quarrying operations tunneling mining slope stability and the use of rock as a construction material the physical and mechanical properties are a function of the mineralogical and textural characteristics of the rock the purpose of this study is to apply correlation analysis to investigate the relationships between petrographical and engineering properties of granitic rocks a variety of granitic rock samples from different parts of turkey were subjected to petrographic studies the same samples were then tested to determine specific gravity dry and saturated unit weight water absorption effective and total porosity sonic velocity schmidt hardness point load strength index uniaxial compressive strength tensile strength and modulus of elasticity the relationships between these properties and the petrographical characteristics are described by simple regression analyses the study revealed that the influence of the textural characteristics on the engineering properties appears to be more important than the mineralogy it also determined that the types of contacts grain mineral shape and size significantly influence the engineering properties of the granitic rocks

cyclic changes in pennsylvanian paleoclimate and effects on floristic dynamics in tropical pangaea abstract wetland floras narrowly define perceptions of pennsylvanian tropical ecosystems the so called coal age such wetlands reflect humid to perhumid climate leading to characterizations of pennsylvanian tropics as everwet swampy these views are biased by the high preservation potential of wetlands sedimentation patterns paleosols and fossil floras indicate the presence of vegetation tolerant of subhumid to dry subhumid perhaps semi arid climate in basins between peat formation times understanding the significance of this seasonally dry vegetation has suffered from conceptual and terminological confusion a clearer view has emerged as models for framing the data have improved basinal floras typical of seasonally dry conditions relatively low soil moisture regimes are well documented but mainly from isolated deposits some of the earliest dominated by primitive pteridosperms flozfern floras occur in clastic rocks between european early pennsylvanian coal beds later early pennsylvanian fern cordaitalean vegetation different from coal floras is preserved in marine goniatite bullions conifers are first suggested by late mississippian potoniesporites pollen about the same time in north america broadleaf foliage lesleya and megalopteris occur in basin margin settings on drought prone limestone substrates the best known xeromorphic floras found between coal beds appear in the middle through late pennsylvanian containing conifers cordaitaleans and pteridosperms the middle pennsylvanian appearances of this flora are mainly allochthonous though parautochthonous occurrences have been reported parautochthonous assemblages are mostly late pennsylvanian the conifer flora became dominant in western and central pangaean equatorial lowlands in earliest permian location of the humid perhumid wetland flora during periods of relative dryness though rarely discussed is as or more perplexing than the spatial location of seasonally dry floras through time wetland plants had few migratory options and possibly survived in small refugia within and outside of basins coupled oscillations in climate sea level and vegetation were driven most likely by glacial interglacial fluctuations perhaps controlled by orbital cyclicity

contribution of saharan dust to mediterranean soils assessed by sequential extraction and pb and sr isotopes abstract measurements of the concentrations and isotopic composition of pb and sr in al silicates and fe oxides of two soil profiles developed in the guadalquivir river basin andalusia southwestern spain are used in order to estimate the significance of local versus foreign sources lead concentrations are 10 6 mg kg in deep more than 100 cm soil samples and reach 30 60 mg kg near the surface 206 pb 207 pb values range from 1 200 to 1 206 in deep samples and from 1 186 to 1 191 in the upper most samples sr concentrations range from 30 to 69 mg kg showing no systematic trend with depth 87 sr 86 sr ratios range from 0 71753 to 0 72526 also with no systematic changes with depth in the fe oxide fraction but with a systematic increase in values with depth in the al silicate fraction of one of the soil profiles in all the samples the isotopic composition of pb in the al si fraction is slightly more radiogenic than its value in the fe oxide fraction the isotopic composition of sr exhibits the opposite behavior and 87 sr 86 sr values in the fe oxide fraction are always higher than in the al silicate fraction based on our data we calculate that al silicates in the fine soil fraction less than 5 m in both sites contain 33 86 of saharan dust and that the fe oxides contain less saharan dust and more material released by the weathering of basement granitoid type rocks in the case of pb a third source is present in the upper part of the soil i e anthropogenic pb probably added to the soil over millennia the results of the present study suggest that saharan dust makes up a significant fraction in al silicates and fe oxides of mediterranean soils but that local sources both natural rock derived and anthropogenic are not trivial

the evolution of holocene coastal dunefields jutland denmark a record of climate change over the past 5000 years coastal dunefields have developed on the west coast of jutland in denmark over the past 5000 years the dunefields are situated in a temperate climate zone with frequent high energy wind events dunefield development was characterized by repeated periods of transgressive dune formation punctuated by periods of dune stabilization and soil formation the chronology of dunefield evolution is based on accelerator mass spectrometry ams radiocarbon dating of peaty palaeosols 24 samples and optically stimulated luminescence osl dating of aeolian sand deposits 19 samples these dates indicate that the completeness of the stratigraphic record varies considerably but that the timing of aeolian activity events was identical in the dunefields examined here initiation of aeolian activity occurred around 2200 bc 800 bc ad 100 ad 1050 1200 and between ad 1550 and 1650 proxy climate data from bogs in southwestern sweden suggest that these periods of dunefield activity were initiated during wet cool summers most likely these climatic situations were associated with a more frequent passage of cyclones across denmark in the summer seasons increased storminess causing aeolian sand movement and dune formation the continued removal of vegetation in jutland between 4000 bc and ad 1850 allowed the aeolian sand when first activated to move more and more easily across the coastal plains the final phase of aeolian sand movement between ad 1550 1650 and 1900 had catastrophic implications for many coastal inhabitants in the region c 2008 elsevier b v all rights reserved less

petrology palynology and depositional environments of coals of the upper carboniferous barachois group westphalian a and c southwestern newfoundland coal samples from the barachois group of western newfoudland vary in rank from high volatile c to high volatile a the coals are vitrinite rich 70 except some from coal brook that contain substantial quantities of inertinite up to 52 liptinite ranges up to 18 but is a relatively minor component the most abundant constituents amongst the three maceral groups are vitrinite vitrinite a inertinite semifusinite and liptinite sporinite compositional profiles in three of the seams show no clear correlation between maceral group content and stratigraphic position the barachois group coals are relatively high in ash mean 12 8 and sulphur mean 6 9 spore assemblages from coal samples of the barachois group indicate a westphalian a age in the barachois brook and coal brook areas and a westphalian c age along blanche brook barachaois coals are part of a mudstone dominated facies association that developed in an assemblage of floodplain environments plots of tissue preservation gelificat

a geomagnetic polarity timescale for the carboniferous the geomagnetic polarity pattern for the carboniferous is incompletely known but with the best resolved parts in the serpukhovian and bashkirian hence data from both igneous and sedimentary units are also used in an additional polarity bias evaluation in the tournaisian to mid visean interval polarity is mainly derived from palaeopole type palaeomagnetic studies allowing identification of polarity bias chrons seven polarity bias chrons exist in the mississippian mi1nb to mi4nb with an additional 33 conventional magnetochrons and submagnetochrons mi4r to mi9r the moscovian and gzhelian polarity is best resolved in magnetostratigraphic studies from the donets basin and the southern urals dispute about the reliability of these data is ill founded since an assessment of supporting data from palaeopole type studies suggests that these datasets currently provide the best magnetic polarity data through the pennsylvanian polarity bias assessment indicates a normal polarity bias zone in the kasimovian in the pennsylvanian there are 27 conventional magnetochrons and submagnetochrons pe1n to ci1r and one normal polarity bias chron pe8nb the kiaman superchron begins in the mid bashkirian with clear data indicating brief normal polarity submagnetochrons within the superchron the magnetochron timescale is calibrated using 31 u pb zircon dates and a quantitative bayesian based age scaling procedure

aeolian dust transport and deposition over crete and adjacent parts of the mediterranean sea monitoring of dust deposition at several stations on crete over a three year period has shown that the present day depositional flux is of the order of 10 100 gm 2 yr 1 most of the dust deposition takes place during a few annual dust events which typically last for 1 3 days dust haze episodes are usually associated with southerly or southwesterly winds which transport fine sediment from north africa dust is raised by a wide variety of meteorological conditions which generate strong near surface winds in the source areas but major long range transport events are often associated with cold fronts linked to the passage of deep mid latitude depressions during winter and spring dust haze frequency and deposition rates are highest in western crete and decrease towards the east suggesting that transport from tunisia and neighbouring parts of north africa is particularly important the measured rate of dust deposition is well below the minimum level required for loess formation deposits which have previously been identified as loess are shown to be uncemented marine marls of tertiary age laboratory analysis of red soils surface sediments and bedrock samples has confirmed that many of the soils contain an important aeolian dust component but it is concluded that a more important source of soil parent material is provided by weathering of local rocks many of the soils contain significant amounts of quartz sand which cannot have been transported across the sea from north africa reworking of weathered material and deposited dust is extensive and is accomplished by both aeolian and fluvial processes tectonically controlled depressions in the mountains and parts of the coastal lowlands have acted as long term sinks in which a thickness of several metres of sediment and soil has accumulated during the quaternary

soil evolution over the quaternary period in a mediterranean climate se spain palaeosols in the granada basin se spain have been studied in two different situations surface soils on geomorphically stable surfaces since the early pleistocene with younger pedogenic overprinting and buried soils on unstable surfaces from the middle late pleistocene on which successive erosional depositional episodes have alternated with pedogenic episodes for each soil clay and iron accumulation indices the fet alt sit ratio clay mineralogy and micromorphological features were used to estimate the degree of soil development from the early to the early late pleistocene the main pedogenic processes were the leaching of carbonates weathering illuviation and rubification which resulted in bt horizons with red colours clay texture clay coatings and kaolinite neoformation the degree of weathering and the development of these bt horizons varied over time and the soils that formed on the surfaces from the early pleistocene show strongest weathering and development however after their formation there were periods in which they were partially truncated and recalcified resulting in polygenetic soils the different degrees of development of the buried soils during the last 474 000 years indicate that the wettest warm period was stage 7 and the driest stage 5 stages 9 and 11 must have had climates with intermediate wetness since the clay accumulation and iron oxide accumulation indices the differences in fet alt sit ratio between bt and c horizons the extent of kaolinite neoformation and the micromorphological features of the soils formed during stage 7 are all similar to the surface soils that formed on early pleistocene deposits these features cannot be used to date surfaces older than 242 000 bp by contrast the soils that formed during stage 7 and later periods show different extents of development and thus can be used for the approximate dating of landforms d 2002 elsevier science b v all rights reserved

late pleistocene loess palaeosol sequences in the vojvodina region north serbia late pleistocene loess palaeosol sequences are widespread in the vojvodina region with thicknesses reaching a maximum of about 20 m our investigations include more than 40 of these loess sections geochronology of the last glacial loess palaeosol sequences based on lumines cence dating and amino acid racemisation provides correlations between upper pleistocene loess palaeosol sediments in vojvodina and comparable deposits at other european localities sedimentary logs of magnetic susceptibility grain size measurements and carbonate content combined with malacological evidence indicate two main relatively cold and arid phases during the last glacial period related to intensive accumulation of loess units l1l1 and l1l2 as well as many brief episodes of dry and windy climatic conditions suggesting a possible relationship with cold events recorded in the north atlantic region generally late pleistocene climate in the region was dry and relatively warm compared with glacial period sites in central europe and was characterised by sharp differences between glacial and interglacial modes new data and interpretations presented in this study emphasise the significance of loess palaeosol sequences in vojvodina for the reconstruction of the temporal and spatial evolution of late pleistocene palaeoclimate in this part of europe copyright 2007 john wiley sons ltd

palynology phytogeography and climate of the lower carboniferous abstract palynological assemblages of the tournaisian 2 visean 1 period from different areas show distinct compositional differences based on these differences three palynophytogeographical areas have been recognized north euramerica south euramerica and australia a climatic model for this period has been reconstructed using the distribution of climate sensitive rocks climatic belts obtained coincide with the palynophytogeographical areas recognized analogously to recent phytogeography these both palynophytogeographically and climatologically characterized areas are formally termed regions viz the vallatisporites region the lophozonotriletes region and the frustulentus region various aspects relevant to the recognition of regions and their implications for world geography are discussed the palynoflora from cathaysia is intermediate in composition between that from the vallatisporites region and that from the frustulentus region this implies the existence of migration routes between euramerica and cathaysia and between australia and cathaysia consequently a position of the asian continent in between euramerica and australia is proposed the palynophytogeography climatology relationship established for the tn 2 vis 1 period has been applied to the whole early carboniferous differences in entry of taxa between areas could be related to differences in climatic conditions since the latter are related to world geography it has been possible to relate the presence of taxa with world geography and with continental drift the following conclusions may be drawn 1 1 the first appearance in the late visean of south euramerica of taxa which were already present in the early visean of north euramerica indicates the establishment in the late visean of south euramerica of climatic conditions which were already present in the early visean of north euramerica in order to explain the changing climatological conditions a northward drift of euramerica is proposed 2 2 the proposed northward drift of the euramerican continent provides a suitable explanation for the longer presence in australia of taxa which disappeared earlier in south euramerica 3 3 furthermore the proposed northward drift of the euramerican continent provides an explanation for the increasing divergence of palynological assemblages between gondwanaland and euramerica since the tournaisian visean transition

geomorphology stratigraphy and facies analysis of some late pleistocene and holocene key deposits along the coast of sardinia italy abstract two major synthems have been recognised along the coasts of sardinia the older one is composed of two sub synthems the oldest of which was formed in high energy boulder beaches and is a thin condensed transgressive sequence usually located at the foot of a marine cliff the overlying sub synthem was generated by aeolian slope interdunal ponds and alluvial depositional environments it is widespread and terraces and relict dune fields are usually deeply dissected its deposition is associated with a cold and arid climate the aeolian and alluvial deposition was interrupted by the evolution of steppe prairie soils a more evolved reddish brown bt paleosol is locally found at the top of the sequence the younger synthem is made of beach and coastal lagoon and swamps it is more variable in thickness rests unconformably over the older one and has no sedimentary cover it is laterally correlated to the present day depositional environments such as alluvial plains and beaches unfortunately because beach deposits of this synthem are found up to 6 m asl and a marine notch is present at 5 6 m capo san marco the widespread idea that sardinia is a stable area and that marine sea level during the holocene was never higher than nowadays led to their previous attribution to mis 5e however all the stratigraphic geomorphic and pedological evidence indicates that only the older sub synthem can be correlated with the mis 5e high stand the younger sub synthems made of aeolian lacustrine and alluvial deposits at cala gonone santa reparata capo s marco and s giovanni di sinis were deposited during the rest of the late pleistocene the younger synthem evolved during the holocene and this is the chronological setting of the beach deposits at is arenas scala e croccas santa reparata and capo san marco radiocarbon dating confirms these attributions unfortunately osl dating suggests an older chronology for these deposits and therefore it seems that further investigations are needed

initial thermal conditions around an underground research tunnel at shallow depth the initial thermal conditions around a shallow research tunnel in korea were investigated based on the data analysis of rock properties in situ observation and a computer simulation the measured thermal conductivity data were used for evaluating different theoretical estimations based on mineral composition porosity and saturation with a consideration of total porosity which was assumed to be twice of effective porosity the prediction with geometric mean could be improved in the case of three phase system consisted of minerals water and air however geometric mean overestimated especially in low saturation condition by using the chaudhary and bhandari equation for three phase system we could predict the measured thermal conductivity with about 10 error in low saturation condition with the data of porosity variation and saturation expected at kurt it was possible to predict the thermal conductivity increases with depth and stabilized at 3 2 w mk below 50 m considering the surface topography around kurt sequential tunnel excavation depth dependent rock properties and seasonal temperature variation of the air the time and depth dependent thermal conditions around kurt were predicted by a three dimensional computer simulation using flac3d

optically stimulated luminescence dating of young sediments a review optically stimulated luminescence osl dating of young 1000 years sediments is used increasingly in a wide variety of late holocene studies as a mean of establishing contemporary sedimentation rates or the timing of sediment deposition this paper provides a summary of the basic principles of osl dating outlines the problems specific to the dating of young material and then uses recent applications to young sediments to illustrate the greatly increased scope and potential of the method in geomorphology and the geology of recent deposits the overall reliability of this new generation of osl ages is examined by comparing where possible osl ages with independent age control it is concluded that the osl ages are accurate in that there is no evidence for systematic over or under estimation it is our conclusion that osl dating should be regarded as a reliable chronological tool for determining the time of deposition of water lain sediments from the coastal zone and aeolian deposits from both coastal and inland environments our conclusion is supported by the growing popularity of osl dating in geomorphology and geology

palaeoclimate and palaeoenvironmental responses in the western mediterranean over the last 140 ka evidence from mallorca spain climatic change in the western mediterranean basin over the last 140 ka has been investigated from sediment and soil sequences along the coast of the northeastern part of mallorca spain palaeoclimate and palaeoenvironments are reconstructed from sediment and soil structures marine and terrestrial molluscan fauna grain size distributions mineral magnetics sediment and soil chemistry sem and oxygen isotope values dating is by osl and amino acid geochronometry along with marine molluscan faunal assemblages all oxygen isotope stages and substages from ois 6 to 1 are recorded mean annual temperatures m a t of c 19 2 c for the climatic optimum of the last interglacial compare with c 17 3 c for the present and are associated with high sea level extensive woodland and stable soils although wide temperature ranges are detected during this stage with values as low as c 10 3 c through ois 5d to 5a m a t fluctuated from 8 2 c to 17 9 c low sea level open vegetation effective river activity and aeolian sand and dust deposition characterize 5d and 5b while relatively high sea level and soil development on stable landscapes dominate ois 5c and 5a ois 4 is represented by m a t of c 4 9 c with aeolian sand and loess deposition limited river activity and weak soil development loess deposition persisted into ois 3 but at this time the m a t was c 13 c and with higher humidity and vegetation growth during the lgm ois 2 m a t was c 8 1 c and effective river slope and aeolian processes along with associated with limited vegetation cover were responsible for the most extensive changes in the landscape major rates of change occur during periods of climatic deterioration when the high levels of geomorphic energy were imposed on a landscape undergoing a breakdown of vegetation cover

storm controlled oblique dunes of the oregon coast the large mean height 25 m spacing 300 m relatively straight crested dunes of the central oregon coast migrate an average of 3 8 m yr toward an azimuth of 26 the dunes are transverse to the strong south southwesterly winter storm winds that are responsible for their basic form orientation and migration the dry moderate north northwesterly summer winds modify the dune form but not the dune trend comparison of the sand transport calculated from wind data and the transport measured from dune migration indicates that the actual transport by the wet southerly winds is only one third of the amount calculated assuming dry conditions the resultant vector mean transport rate as recalculated by comparison of the measured and initially calculated rates is 34 m 3 m yr toward an azimuth of 45 the dunes are thus oblique by our definition of an oblique dune angle between dune trend and resultant transport direction between 15 and 75 the internal structures of the dunes confirm northward migration during wet conditions evidence for deposition during wet conditions includes slipface deposits deformed mostly by sliding and various structures formed by the adhesion of sand grains to wet surfaces most summer deposits are not preserved but those on the basal apron the gentle north slope at the base of the winter slipface have a high preservation potential a depositional model based on dune climbing predicts that the preserved record of oblique dunes formed by an obtuse bimodal wind regime would consist of tabular sets of crossbeds in which the dip angles increase upward from the base of each set

an absolute chronology for the raised beach and associated deposits at sewerby east yorkshire england the raised beach sediments revealed in the cliffs at sewerby east yorkshire are widely regarded as ipswichian in age previously reported evidence for this dating is reviewed and new results from a range of luminescence dating techniques applied to the blown sand deposit overlying the raised beach are reported these provide the first absolute date for the sewerby site of 120 84 11 82 ka which places the blown sand at the boundary between oxygen isotope stages ois 5e and 5d as the underlying raised beach is little older than the blown sand it probably formed during ois stage 5e as suggested by the faunal evidence

sedimentary and pedological processes in the upper pleistocene loess of northern italy the bagaggera sequence abstract the bagaggera sequence consists of two late pleistocene loesses superimposed on the top of middle pleistocene fluviatile sediments the lower loess includes at its base a mousterian archaeological level represented by artifacts dated by tl as 60 500 7500 bp and charcoal from hearths which mainly consists of boreal forest species at the top of the lower loess aurignacian artifacts occur which suggest a tentative date of 35 000 bp the sedimentary and pedological processes which lead to the formation of the sequence were reconstructed by means of mineral and textural analyses and thin section analysis and can be summarized as follows erosion and colluviation of the eemian soil at the base of the sequence during the early wurm isotopic substages 5 a c sedimentation of the lower loess deposits during the first pleniglacial period isotopic stage 4 a large number of coarse pedofeatures in this soil suggests that primary aeolian dust has been redistributed in place or for short distances by syngenetic slight pedogenesis and by water reworking as a result of alternating phases of wet and dry climate an alfisol characterized by strong clay illuviation developed in the lower loess during the hengelo arcy interstadial phase its top was affected by reworking and slight frost activity at the beginning of the second pleniglacial period isotopic stage 2 the upper loess was deposited in a drier environment during the second pleniglacial period isotopic stage 2 water reworking was less effective holocene weathering is expressed by clay illuviation and slight hydromorphism

characteristics nature and formation of palaeosurfaces within dunes on fuerteventura the appearances of palaeosurfaces intercalated into palaeo dune fields on fuerteventura are multifaceted although reddened layers in these dune sediments might suggest that strong soil formation processes have taken place the combination of aridity and parent material namely biogenic carbonate sand of shelf origin reveals that strong soil formation seems unlikely these sediments rather represent de and recalcification processes only solely in the case of admixed material of volcanic origin and dust deposits further soil forming processes seem to be possible hematite rich saharan dust contributes to reddish colouration of the palaeosurfaces in addition caco3 coated iron particles appear to be ingredients of dust being leached after deposition and transformed to hematite overall we propose much weaker soil forming processes during the pleistocene than previously postulated our findings support the relevance of local environments carbonate sands of shelf origin hinder strong soil formation and the reddish layers separating dune generations are palaeosurfaces which mainly consist of saharan dust after deposition of allochthonous material these layers are overprinted by weak soil forming processes the formation of palaeosurfaces primarily depends on morphodynamically stable periods during limited sand supply our data suggest a cyclicity of processes in the following order 1 sand accumulation 2 dust accumulation and weak soil formation and 3 water induced erosion for the canary islands we support the assumption of glacial maxima being periods of increased levels of moisture in combination with rising sea level we propose that favorable conditions of surface stability occur immediately after glacial maxima during periods of starting transgression whereas regression periods immediately after sea level high stands seem to yield the highest sand supply for the study area

middle to late pleistocene dunefields in rocky coast settings at cala xuclar eivissa western mediterranean recognition architecture and luminescence chronology abstract this study focuses on cliff front anchored and sand ramp aeolian dune accumulations in cala xuclar eivissa ibiza western mediterranean during different sea level falling stages from middle to late pleistocene times stratigraphic mapping conventional lithostratigraphic logging and osl datings are used to reconstruct dune formation and evolution facies analyses result in the identification of six sedimentary units three of which correspond to dune deposits formed at mis 6 145 ka mis 5d c 100 ka and mis 4 77 73 ka respectively additionally there is a beach deposit at 2 m above present msl which resembles the mis 5a this study concludes that each dune system corresponds to a relatively low sea level stand that exposed enormous amounts of marine carbonate sands that was transported inland by migrating dunes under strong north westerly winds therefore sea level fall and the related sediment supply owe likely to be key factors in the formation of these aeolianites systems

late paleozoic strike slip faults in maritime canada and their role in the reconfiguration of the northern appalachian orogen major late paleozoic faults many with documented strike slip motion have dissected the ordovician devonian appalachian orogen in the maritime provinces of atlantic canada activity alternated between east west faults minas trend and ne sw faults appalachian trend nw se faults canso trend were probably conjugate to minas trend faults major dextral movement on faults with appalachian trend in total between 200 and 300 km began in the late devonian this movement initiated the maritimes basin in a transtensional environment at a releasing bend formed around a promontory in the laurentian margin and thinned the crust accounting for the major subsidence of the basin appalachian trend strike slip continued in the mississippian but was accompanied by major movement on e w minas trend faults culminating around the mississippian pennsylvanian boundary juxtaposing the meguma and avalon terranes of the appalachians close to their present day configuration however strike slip continued during the pennsylvanian permian interval resulting in transpressional deformation that reactivated and inverted earlier extensional faults a final major episode of transtension mainly sinistral occurred during the mesozoic opening of the atlantic ocean restoration of movements on these faults amounting to several hundred kilometers of slip explains anomalies in the present day distribution of terranes amalgamated during early paleozoic appalachian tectonism in the restored geometry the nashoba and ellsworth terranes of ganderia are adjacent to one another and the meguma terrane lies clearly outboard of avalonia a restored post acadian paleogeography not the present day geometry of the orogen should be used as a basis for reconstructions of its earlier paleozoic history

multidisciplinary characterization of the middle holocene eolian deposits of the elsa river basin central italy abstract in temperate regions eolian deposits of different natures are often pedogenically altered and mixed with underlying sediments the research reported in this paper identifies for the first time the presence of eolian deposits in soils of central tuscany and investigates the characteristics and origin five relict polycyclic paleosol profiles were studied p1 was situated in a natural dust trap a doline on top of an isolated limestone hill p2 and p3 were both situated on a limestone plateau and p4 and p5 on a mid and foot slope on schist the profiles were sampled for routine analyses iron forms heavy minerals major and trace elements and pollen spores and non pollen palynomorphs undisturbed samples were taken for micromorphological and sem analyses nine soil horizons were sampled for osl dating eolian deposits were dominant or abundant in the first layers of p1 p2 and p3 osl age determinations of soil horizons deriving from eolian parent material were middle holocene chemical and heavy mineral analyses indicated different possible sources including bare slopes alluvial fans and wide channels coming from the nearby streams that drain the middle tuscany ridge and the mounts of chianti marginal contribution of volcanic ashes was only found in p1 the research demonstrated that wind soil erosion accompanied water erosion and colluvial deposition during the middle holocene in the elsa river basin pollen spectra in particular indicated that soil degradation occurred in an environment showing signs of incipient desertification resulting from an increase of aridity in a land already strongly influenced by humans although central italy is currently considered to be only marginally affected by wind soil erosion a climate change which would imply increased arid conditions could trigger a new cycle of slope denudation wind erosion and loess deposition

geochemical evidence for african dust and volcanic ash inputs to terra rossa soils on carbonate reef terraces northern jamaica west indies abstract the origin of red or reddish brown clay rich terra rossa soils on limestone has been debated for decades a traditional qualitative explanation for their formation has been the accumulation of insoluble residues as the limestone is progressively dissolved over time however this mode of formation often requires unrealistic or impossible amounts of carbonate dissolution therefore where this mechanism is not viable and where local fluvial or colluvial inputs can be ruled out an external source or sources must be involved in soil formation on the north coast of the caribbean island of jamaica we studied a sequence of terra rossa soils developed on emergent limestones thought to be of quaternary age the soils become progressively thicker redder more fe and al rich and si poor with elevation furthermore although kaolinite is found in all the soils the highest and oldest soils also contain boehmite major and trace element geochemistry shows that the host limestones and local igneous rocks are not likely source materials for the soils other trace elements including the rare earth elements ree show that tephra from central american volcanoes is not a likely source either however trace element geochemistry shows that airborne dust from africa plus tephra from the lesser antilles island arc are possible source materials for the clay rich soils a third as yet unidentified source may also contribute to the soils we hypothesize that older more chemically mature jamaican bauxites may have had a similar origin the results add to the growing body of evidence of the importance of multiple parent materials including far traveled dust to soil genesis

geochemical evidence for african dust inputs to soils of western atlantic islands barbados the bahamas and florida 1 we studied soils on high purity limestones of quaternary age on the western atlantic ocean islands of barbados the florida keys and the bahamas potential soil parent materials in this region external to the carbonate substrate include volcanic ash from the island of st vincent near barbados volcanic ash from the islands of dominica and st lucia somewhat farther from barbados the fine grained component of distal loess from the lower mississippi river valley and wind transported dust from africa these four parent materials can be differentiated using trace elements sc cr th and zr and rare earth elements that have minimal mobility in the soil forming environment barbados soils have compositions that indicate a complex derivation volcanic ash from the island of st vincent appears to have been the most important influence but african dust is a significant contributor and even mississippi river valley loess may be a very minor contributor to barbados soils soils on the florida keys and islands in the bahamas appear to have developed mostly from african dust but mississippi river valley loess may be a significant contributor our results indicate that inputs of african dust are more important to the genesis of soils on islands in the western atlantic ocean than previously supposed we hypothesize that african dust may also be a major contributor to soils on other islands of the caribbean and to soils in northern south america central america mexico and the southeastern united states dust inputs to subtropical and tropical soils in this region increase both nutrient holding capacity and nutrient status and thus may be critical in sustaining vegetation

dirtmap the geological record of dust atmospheric dust is an important feedback in the climate system potentially affecting the radiative balance and chemical composition of the atmosphere and providing nutrients to terrestrial and marine ecosystems yet the potential impact of dust on the climate system both in the anthropogenically disturbed future and the naturally varying past remains to be quantified the geologic record of dust provides the opportunity to test earth system models designed to simulate dust records of dust can be obtained from ice cores marine sediments and terrestrial loess deposits although rarely unequivocal these records document a variety of processes source transport and deposition in the dust cycle stored in each archive as changes in clay mineralogy isotopes grain size and concentration of terrigenous materials although the extraction of information from each type of archive is slightly different the basic controls on these dust indicators are the same changes in the dust flux and particle size might be controlled by a combination of a source area extent b dust emission efficiency wind speed and atmospheric transport c atmospheric residence time of dust and or d relative contributions of dry settling and rainout of dust similarly changes in mineralogy reflect a source area mineralogy and weathering and b shifts in atmospheric transport the combination of these geological data with process based forward modelling schemes in global earth system models provides an excellent means of achieving a comprehensive picture of the global pattern of dust accumulation rates their controlling mechanisms and how those mechanisms may vary regionally the dust indicators and records of terrestrial and marine palaeoenvironments dirtmap data base has been established to provide a global palaeoenvironmental data set that can be used to validate earth system model simulations of the dust cycle over the past 150 000 years

recognizing products of palaeoclimate fluctuation in the fluvial stratigraphic record an example from the pennsylvanian to lower permian of cape breton island nova scotia tectonics and climate are the major extrinsic upstream controls on both the external and internal architectures of fluvial channels while the role of tectonics has been well documented the role of climate has received less attention because both tectonics and climate can produce similar stratigraphic architectures the ability to recognize and differentiate these has major ramifications for the interpretation of fluvial stratigraphy the pennsylvanian to permian succession of the maritimes basin complex on cape breton island is ca 5 km thick and is composed of predominantly non marine strata deposited within a series of depocentres characterized by different subsidence regimes basins in the west are transtensional depocentres characterized by episodic fault movement in contrast basins in the east were formed during prolonged periods of passive thermal subsidence the stratigraphy is composed of four second order sequences a to d each 5 to 10 myr in duration these sequences are composed of amalgamated fluvial channel deposits that fine upwards into extensive mud dominated floodplain deposits with isolated fluvial channel bodies a spectrum of fluvial styles is recorded within the study area including perennial perennial intermittent and ephemeral four stratigraphic intervals e1 to e4 are recognized in which the deposits of strongly seasonal perennial intermittent fluvial deposits are predominant these intervals 2 to 6 myr in duration are correlated across the study area between basins with differing tectonic regimes and do not correlate with a particular position in second order sequences this suggests that climate exerted the dominant influence on the formation of these intervals and can be differentiated from tectonic imprints while the tectonic regime of a particular basin exerted a fundamental control on the external architecture a coherent record of climate change is recognized in the internal architecture of fluvial units this study demonstrates that tectonic and climatic controls can be recognized and differentiated in vertical successions by evaluating the changes in fluvial architecture