luminescence dating of sediments from buctouche spit new brunswick in this paper we describe our efforts to determine the formation chronology of a sequence of dunes on buctouche spit a holocene deposit on the northeast coast of new brunswick optical dating using infrared stimulation of k feldspar grains yielded ages ranging from 5 30 a for an embryo dune to 765 45 a for the oldest dune thermoluminescence ages although less precise support the recent formation of the dunes the ages exhibit the expected sedation from youngest to oldest and are consistent with historical evidence coupled with an assumed constant sediment aggradation rate the age resolution obtained was very good and we conclude that the optical dating method used here shows great promise

reconstruction of holocene foreland progradation using optically stimulated luminescence osl dating an example from dungeness uk roberts helen plater a j 2007 reconstruction of holocene foreland progradation using optically stimulated luminescence osl dating an example from dungeness uk the holocene 17 4 pp 495 505 rae2008

widespread middle holocene dune formation in the eastern upper peninsula of michigan and the relationship to climate and outlet controlled lake level dating of five widely spaced noncoastal dunes in eastern upper michigan by optically stimulated luminescence of quartz establishes that eolian sand was last mobilized between ca 7 and 5 5 ka in the region although this interval corresponds to the drier altithermal hypsithermal period climate alone may not have been sufficiently arid to cause dune formation in this area instead it appears that dune formation may also be linked to depressed water tables associated with outlet controlled low levels in lakes michigan and superior following dune stabilization peat began to accumulate in interdune areas ca 4 4 ka

palaeotsunamis along canada s pacific coast abstract to fully understand tsunami hazards along canada s pacific coast we must consider all potential sources including local and region wide earthquakes volcanic activity slope failure events and bolide impacts furthermore as climate changes future extreme meteorological conditions will exacerbate slope failures on steep and over steepened slopes and potentially augment the magnitude and frequency of earthquake generated tsunamis there have been numerous reviews of the geological records of palaeotsunamis along the cascadia margin but as yet there has been no attempt made to pull together all data related to palaeotsunamis along the pacific coast of canada we summarise all geological data related to palaeotsunamis reported in the region all relevant non geological data and other information concerning potential tsunamigenic sources evidence for between 10 and 22 palaeotsunamis prior to european arrival have been documented with the cascadia subduction zone y event ad1700 being the most widely recognised geological archaeological and anthropological data all indicate a complex multi sourced prehistory of seismic tsunami activity that is poorly understood a clustering of potential activity off the se coast of vancouver island suggests that we should also attempt to better understand locally generated events along canada s pacific coast

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

optical dating of a fimic anthrosol in the southern netherlands plaggen agriculture was the dominant land use system in the pleistocene cover sand area of northwest europe before the introduction of chemical fertilisers in today s landscape fimic horizons and driftsand deposits are characteristic survivors of plaggen agriculture the age and accumulation rate of these phenomena cannot be satisfactorily determined by conventional methods like pollen analysis and radiocarbon dating the results of optical dating applied to a fimic horizon of a plaggen soil near weert netherlands are compared with those from conventional methods

late holocene aeolian sedimentation in the tottori coastal dune field japan sea affected by the east asian winter monsoon many dune fields that have formed along the southern coast of the japan sea are influenced by the north westerly winter monsoon which transports beach sand landwards the tottori coastal dune field of the japan sea has not been disturbed much by human activities until the 20th century and thus is expected to provide a continuous record of the relationships between the winter monsoon and aeolian sedimentation we examined new ground penetrating radar profiles and optically stimulated luminescence osl ages of quartz sand from transverse dune ridges in the western part of the dune field in addition to existing data in the eastern part this allowed us to extend the study period to cover the past 1000 years and to effectively compare the sedimentary record with other coastal dune fields in east asia and other palaeoenvironmental proxies osl ages from older dune sediments suggest considerable aeolian activity from the 10th to 12th century ad whereas a hiatus of dune sediment record between the 12th and 15th centuries was detected these results suggest that during the medieval period aeolian activity was low or that extensive erosion removed most of the deposits since the late 15th century dune sedimentation has apparently been broadly continuous though with periods of higher and lower activity in both of the eastern and western parts most of the dune ridges accreted landwards but clear seaward accretion occurred during the 18th century possibly reflecting a decrease in wind strength that restricted sand transport in contrast two significant landward accretion events are inferred to have occurred from the late 15th to 17th centuries and around 1840 corresponding to periods of increased dust fall in china which suggests an enhanced winter monsoon and to cold periods suggested by the decline of the sunspot number the timing of periods of inactive and active dune sedimentation inferred from alternations of organic soil and aeolian sand in other coastal dune fields of east asia appears to be concordant with corresponding periods in the tottori dune field we thus propose that other japan sea dune fields may also provide a valuable record of east asian winter monsoon fluctuations

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

late holocene inland dune activity in the uk a case study from breckland east anglia inland dune fields found in breckland east anglia uk have previously been correlated with the widespread late devensian coversands of the region and a seventeenth century sandflood which is known to have inundated the village of santon downham a programme of optically stimulated luminescence and radiocarbon dating undertaken on the dunes at wangford warren and santon downham reveals that episodic aeolian activity has taken place during the last 7000 years five sand depositional phases on breckland dunes are identified c 6500 c 1600 1100 c 500 c 400 335 and from c 200 30 years before present between c 2120 1840 years ago and within the period 1100 300 years ago quiescent periods allowed the development of fen peat and soils local controlling factors on aeolian activity in breckland appear to be related to anthropogenic activities and livestock sheep and rabbits reducing vegetation cover and decreased precipitation and sea levels which led to lowering of water tables breckland aeolian activity when compared to the national and sub continental holocene aeolian activity record shows a high level of concordance the underlying forcing factor for late holocene dune activity in the uk and elsewhere in europe appears to be climatic instability in the north atlantic associated with both the little ice age and previous similar events which led to increased storminess climatic variability and lower temperatures

basin evolution in the arc arc izu collision zone mio pliocene miura group central japan a comparative study of the present collision zone between the izu bonin ridge island arc with mainland japan honshu arc and the mio pliocene of onshore se japan suggests that arc arc collision processes and the resulting stratigraphic successions may be repetitious and predictable arc arc collision has led to the incremental accretion of segments of delaminated izu bonin arc crust onto the honshu arc associated with the sequential southward migration in jumps of the plate boundary and trench prior to accretion of a segment of izu bonin arc crust the leading edge underwent uplift to generate an approximately trench parallel topographic high the zenisu ridge being the present example with the hayama mineoka uplift zone as a mio pliocene example the ridge separated a northern trench or trough from a southern intra oceanic arc basin during collision accretion the trench received both honshu arc derived terrigenous and izu bonin arc derived volcaniclastic sediments whereas the arc basin tended to receive only arc deposits during the final stages of accretion the arc basin began to receive ever increasing volumes of terrigenous honshu arc derived detritus fed through basement controlled canyons the accretionary process was accompanied by intense deformation and the residual deep marine basin was then infilled above an angular unconformity

the impact of north atlantic storminess on western european coasts a review abstract instrumental and documentary records of storminess along the atlantic coast of western europe show that storm activity exhibits strong spatial and temporal variability at annual and decadal scales there is evidence of periods of increased storminess during the little ice age lia ad 1570 1990 and archival records show that these periods are also associated with sand movement in coastal areas independent evidence of sand movement during the lia is derived from dating the coastal sand deposits using luminescence or radiocarbon methods the holocene record of sand drift in western europe includes episodes corresponding to periods of northern hemisphere cooling particularly at 8 2 ka and provides the additional evidence that these periods like the lia were also stormy

aeolian sand depositional records from western nebraska landscape response to droughts in the past 1500 years the great plains is dominated by presently stabilized dune fields that are indicators of extreme drought in the late holocene this study focused on deciphering the timing of reactivation of dunes in western nebraska stratigraphy adjacent to dune dammed lakes reveals aeolian sand separated by palaeosols indicating mobilization of aeolian sand followed by landscape stability the chronology of aeolian sand depositional events is constrained using the luminescence based single aliquot regeneration method providing resolution to relate dune movement to tree ring and palaeolimnologic records of drought there are at least a six aeolian depositional events in the past 1500 years with apparent mean ages of 1390 130 670 70 470 40 240 40 140 20 and 70 10 yr all study sites show evidence for aeolian accumulation in the twentieth century potentially reflecting the 1930s drought significant aeolian activity is coincident with the tree ring identified sixteenth century megadrought indicating widespread landscape impacts

combining ground penetrating radar surveys and optical dating to determine dune migration in namibia ground penetrating radar gpr profiles across a complex linear dune in the namib sand sea have been used to image sets of cross stratification and their bounding surfaces a combination of radar facies analysis and radar stratigraphy has been used to interpret the radar profiles and define a relative chronology thick sets of cross stratification indicate when the dune was most active whereas thin sets of cross stratification are interpreted to indicate the increased prevalence of wind reversals and lower rates of dune migration with bounding surfaces formed during periods of stabilization non deposition or erosion a drilling and dating campaign was designed on the basis of the dune stratigraphy as defined by the gpr survey sampling was targeted at large sets of cross stratification formed when the dunes were most active and avoiding bounding surfaces formed when the dune was stable or even eroded the results from optical dating give ages between 0 34 0 02 ka and 1 57 0 07 ka indicating a time averaged dune migration rate of 0 12 m a 1 over the past 1600 years

equivalent dose determinations for polymineralic fine grains using the sar protocol application to a holocene sequence of the chinese loess plateau abstract a single aliquot regenerative dose sar protocol involving stimulation of the same disc with an infra red laser diode followed by blue leds was applied to polymineralic fine grains infra red stimulated luminescence irsl and post ir optically stimulated luminescence osl ages are presented for a series of 19 fine grain 4 11 m samples taken from a loess section duowa in the western chinese loess plateau there are significant differences between the equivalent doses and thus the ages for the irsl and post ir osl measurements three potential explanations are investigated incomplete bleaching prior to deposition thermal transfer of charge and initial sensitivity change the question regarding which sequence of ages ir or post ir osl is correct if either is not resolved although the 19 post ir osl ages yield more consistent results it is proposed that the double sar protocol employed may not be correctly monitoring the sensitivity changes relating to either or both natural signals

a chronology of hurricane landfalls at little sippewissett marsh massachusetts usa using optical dating abstract optical dating has been applied to sediments preserved in little sippewissett marsh massachusetts usa which are associated with overwashing of the beach barrier during hurricane strikes on the coast the aims were to determine the hurricane landfall frequency and make comparisons with independent age control and the historical record written sources of hurricane activity along the american east coast are only considered reliable back to the mid 19th century but the sedimentary record is potentially much longer optical dating was applied to quartz grains extracted from thirteen samples within a sediment core from the salt marsh variability in the luminescence characteristics between aliquots was observed and 33 of the measured aliquots were discarded based upon the ratio of the fast component to the medium component the majority of the samples gave normal dose distributions implying homogeneous resetting of the luminescence signal at the time of deposition but three of the samples required application of the minimum age model mam ages ranging between 20 2 and 594 38 years were obtained and are broadly in agreement with independent chronologies thus demonstrating the potential of optical dating in this setting the hurricane record based upon optical dating extends approximately 300 years further back in time than the official national oceanic atmospheric administration noaa record the localised nature of hurricane landfalls means that it will be necessary to collect multiple cores from a number of different sites in order to build up a complete hurricane record for this part of the coast

luminescence dating of holocene aeolian sand movement thy denmark abstract we report on the application of optically stimulated luminescence dating to an investigation of the frequency of periods of aeolian sand movement and dune formation on the coast of thy holocene aeolian sediments interleaved with peaty palaeosols form some of the most complete successions known in western denmark samples were taken from a coastal exposure and an inland archaeological site dosimetry was based on laboratory gamma spectrometry and quartz luminescence measurements used the single aliquot regenerative dose protocol and 470 30 nm stimulation the sand samples cover an age ranging from about 100 years to 4500 years the youngest dates give us confidence that the material was well bleached at deposition good agreement was obtained with the radiocarbon palaeosol ages we identify three main periods of aeolian sand movement starting at about 4200 2700 and 900 years ago at least during the latter two periods significant aeolian sand movement occurred all three phases of aeolian activity were separated by long periods of stability and soil formation a more recent episode of dune formation restricted to the coast and beginning less than 200 years ago may have been triggered by modern coastal erosion

identifying extreme pluvials in the last millennia using optical dating of single grains of quartz from shorelines on australia s largest lake the filling of kati thanda lake eyre kt le australia s inland sea has captured scientific and cultural interest for over a century and a half however despite the presence of multiple shoreli

quaternary deformations along the engadine gruf tectonic system swiss italian alps the engadine line el is a seismically active fault in southeastern switzerland in the field we studied its western segment presently not affected by seismicity but characterised by features suggesting neotectonic motions and the coterminous gruf line uphill and downhill facing scarps offset rivers non equilibrium hydrological conditions and aligned deep seated gravitational slope deformations are dominant in the western sector of the el in the inn valley landform offsets and the most recent fault striations point to oblique left lateral strike slip close to the el at the maloja pass a huge collapse beheaded the inn valley trench excavation with palaeoseismic analysis stratigraphic correlations of quaternary deposits and optically stimulated luminescence dating indicate that the collapse and faulting mostly occurred in the late pleistocene in the bregaglia valley the gruf line stretches along the southwestern extension of the el six deep seated gravitational slope deformations developed along the gruf line and were dated to pre and post last glacial maximum times we suggest that the western sector of the el moved also in a pleistocene time interval during which tectonic forces in the area were probably larger than at present favouring local uplift widespread gravity deformation and retrogressive slope failure at the inn valley head copyright 2007 john wiley sons ltd

sand deposition during the last millennium at aberffraw anglesey north wales as determined by osl dating of quartz abstract ground penetrating radar gpr was used to identify sediment units at the terminus of a small dune field at aberffraw nine samples were taken from boreholes sample locations were based on the stratigraphy established by gpr quartz grains were dated using a single aliquot regenerative dose protocol that allows for sensitivity changes sand deposition at llyn coron aberffraw occurred three times in the last 700 years with initial sand movement occurring around 1331 ad when historical documents record sand being mobilised in a strong storm

building of shore oblique transverse dune ridges revealed by ground penetrating radar and optical dating over the last 500 years on tottori coast japan sea abstract coastal dunes provide valuable information on the past aeolian activity better characterization of internal dune structures and their chronology potentially can greatly improve the interpretation of past environmental changes ground penetrating radar gpr and optically stimulated luminescence osl dating was applied to two transverse dune ridges which are arranged obliquely to the shoreline on the tottori coast japan sea data shows that the inner ridge has a core of pleistocene dune draped with holocene sand while the outer ridge consists only of holocene sand the holocene dune is generally dominated by landward migration but the outer ridge shows a clear seaward accretion during the 18th century ad osl dating showed concordant results with radar stratigraphy and topographic changes since ad 1932 revealed by maps from this we were able to present the first detailed report of the multi decadal to centennial scale dune formation for the last 500 years in east asia contemporaneous with the little ice age during which many european coastal and inland dunes were activated in east asia it is thought that the winter monsoon plays an important role for aeolian processes the seaward migration during the 18th century reflects a decrease in wind capacity which restricted sand transport nearshore being related to decline in winter monsoon revealed by chinese historical documents in contrast two remarkable events of landward accretion occurred in ad 1580 1640 and around ad 1840 respectively corresponding to periods of increased dust fall in china which suggest enhanced winter monsoon the zone of maximum sedimentation shifted through time from the inner to outer ridges and also towards the seaward end of the shore oblique dune ridge reflecting an expansion of the dune field caused by shoreline progradation these suggest that the effective combination of gpr and osl dating was critical in detailed characterization of the complicated depositional pattern of the transverse dune ridge and thus in reconstruction of the past aeolian activity

optical dating of tsunami laid sands abstract the ages of some tsunami deposits can be determined by optical dating a key requirement being that the deposits are derived from sediment that was reworked and exposed to daylight by tidal currents waves wind or bioturbation during the last years before the tsunami measurements have been made using 1 4 ev infrared excitation of k feldspar grains separated from samples of prehistoric tsunami sand sheets and modern analogs of tsunami source sediments at four sites in washington state and british columbia source sands gave equivalent doses indicative of recent exposure to daylight tsunami sand at cultus bay washington yielded an optical age of 1285 95 yr calendric years before a d 1995 1 at 2 this age overlaps the range of from 1030 to 1100 yr determined through a combination of high precision radiocarbon dating and stratigraphic correlation tsunami sands at three sites near tofino and port alberni on vancouver island british columbia have optical ages of 260 20 325 25 and 335 45 yr historical records and radiocarbon dating show that the sand at each of the three sites is between 150 and 400 yr old these optical ages support the hypothesis that the vancouver island sands were deposited by a tsunami generated by a large earthquake on the cascadia subduction zone about 300 yr ago

deformation and fluid pressure variation during initiation and evolution of the plate boundary decollement zone in the nankai accretionary prism 1 the plate boundary decollement zone in the muroto region of the nankai accretionary prism records deformation and consolidation histories that have been affected by temporal changes in fluid pressure microstructural observations and chemical analysis demonstrate that the decollement zone initiated in an interval of porous clayey sediments characterized by cementation due to intergranular bonding of authigenic clays crosscutting relations of microstructures indicate that the decollement zone records two compactive deformations the early compactive deformation involved destruction of porous cemented structure probably caused by fluid pressure fluctuation the late compactive deformation was characterized by clay particle rotation and porosity collapse along the sets of slip surfaces resulting in zones of preferred orientation of clay particles these compactive deformations led to significantly higher bulk densities within the decollement zone compared to the compaction trend of the overlying prism sediments elevated fluid pressure following compactive deformations induced an overconsolidated state within the decollement zone with fluid filled dilatant fractures bulk density abruptly decreases at the top of the underthrust sediments but there is no microstructural evidence for cementation fluids in the dilated fractures and underconsolidated underthrust sediments are potential sources for the elevated fluid pressure in and below the decollement zone resulting in mechanical decoupling of the accretionary prism from underthrust sediments the fault fluid interactions in the muroto region may be applicable to other convergent plate margins where high temperature associated with the subduction of a spreading ridge or hot young oceanic crust enhances diagenesis and cementation

late holocene dune migration on the south texas sand sheet abstract there are a wide variety of vegetated eolian depositional landforms associated with the south texas sand sheet attesting to the past dominance of eolian processes mapping identified two sets of parabolic dunes elongating with winds from the southeast and the northwest parabolic dunes elongated by northwesterly winds are older than ca 200 years and may be associated with eolian depositional events ca 2700 and or 2000 years ago the latest dune migration event associated with southeasterly winds occurred ca 200 years ago and at one site is inset into northwesterly extended parabolic dunes this period of dune migration may be coincident with particularly severe drought identified in the tree ring record centered at ad 1790 when the palmer drought severity index was 4 a threshold of dune movement may have occurred ca in the 11th 15th and 20th centuries when there are two or more consecutive years with a palmer drought severity index of

mid to late holocene coastal dune event stratigraphy for the north coast of northern ireland an event stratigraphy of dune stability instability phases has been reconstructed using 22 radiocarbon and 13 luminescence dates for six dunefields along the north coast of northern ireland there is no evidence for dune development prior to 7000 cal years bp during the early holocene rapid rise in rsl and only limited evidence for sand accumulation in association with the rsl maximum dunefield dates correspond to either the subsequent regressive phase or later the gradual transgressive phase of rsl history in the mid and late holocene at these times accommodation space for dune development and sediment supply were maximized episodes of climatic deterioration particularly at 3100 2400 cal years bp and 650 50 cal years bp the little ice age were marked by widespread dune instability a similar coincidence in timing has been recorded for dune systems elsewhere in northwestern europe and is generally attributed to an increased frequency of storms and storm surges associated with the climat

quartz as a natural luminescence dosimeter abstract luminescence from quartz is commonly used in retrospective dosimetry in particular for the dating of archaeological materials and sediments from the quaternary period the phenomenon of luminescence is related to the interaction of natural radiation with mineral grains by the activation of and subsequent trapping of electrons at defects within the quartz lattice the latent luminescence signal i e the trapped electrons is released when the grains are exposed to stimulation energy in the form of light or heat despite the fact that quartz is most nominally pure sio2 the mineral forms in several different geological settings i e under different pressure and temperature conditions the luminescence emitted from quartz is complex and shows a variety of different components with diverse physical properties this complexity is explained by the variety of defects in quartz that are either intrinsic e g si and o vacancies or related to impurity atoms e g al or ti the concentration of impurity related defects is dependent on the conditions of mineral formation or subsequent alteration experimental data have shown that the luminescence properties of quartz are highly variable with geological source and vary even at a grain to grain level within a sediment as a consequence caution is needed when making any general statements about the luminescence properties of quartz when using luminescence measurements as a dating technique it is necessary to adjust the measurement procedures for each geological provenance furthermore some quartz has luminescence properties that make it problematic or even unsuitable for certain applications these problems can arise from low and changing luminescence sensitivity thermal transfer of trapped electrons thermal instability of the trapped electrons and low saturation dose reviewing the present knowledge reveals that insufficient information is available either to unambiguously link distinctive lattice defects with characteristic luminescence components or even to explain problems observed in application studies by potential dynamics of the defects within the crystal this paper gives some ideas on how future research could utilise innovative analytical tools to identify or map the distribution of lattice defects and how practitioners could relate lattice defects to measured luminescence properties of quartz

luminescence dating of well sorted marine terrace sediments on the southeastern coast of korea abstract along the southeastern coastline of the korean peninsula well developed marine terraces are found at various elevations the ages of these terraces and the time of deposition of the terrace sediments are important to our understanding of the geological history of this area during the quaternary period and represent a unique record of the regional tectonic activity previous efforts to establish a chronology using optically stimulated luminescence osl methods have produced controversial results particularly because of stratigraphic inconsistency and poor reproducibility in this paper the application of osl dating based on the single aliquot regenerative dose sar protocol for quartz is investigated the dependence of equivalent dose on the preheat and cut heat temperatures thermal treatment of the regeneration and test doses respectively are examined linearly modulated luminescence signals from chemically cleaned quartz samples are used to identify the presence of a thermally unstable component with a large optical cross section component a which in part affects the ability to correct for sensitivity changes during measurements and thus the reliability of the equivalent dose estimates in some samples a higher heat treatment after the test dose is shown to improve our ability to measure a dose given in the laboratory before any heat treatment dose recovery test this higher temperature treatment effectively removes component a and hence improves sensitivity correction furthermore the samples were broadly divided into poorly sorted and well sorted based on field evidence the poorly sorted samples contain friable weathered gravel clasts which is a likely post depositional source of quartz grains in general these grains will not have been zeroed prior to deposition and so the poorly sorted samples are rejected from further age studies results obtained from the well sorted samples are reproducible at each sampling location and give ages grouping broadly into 50 70 and 110 120 ka but laterally discontinuous on a scale of tens of km our osl results for the younger group are supported by radiocarbon ages from overlying terrestrial deposits it is concluded that these results point to considerable tectonic activity in the southeast of korea during the late pleistocene

the osl chronology of eolian sand deposition in a perched dune field along the northwestern shore of lower michigan abstract extensive coastal dunes occur in the great lakes region of north america including northwestern michigan where some are perched on high 100 m bluffs this study focuses on such a system at arcadia dunes and is the first to systematically generate optical ages from stratigraphic sections containing buried soils dune growth began ca 4 5 ka during the nipissing high lake stand and continued episodically thereafter with periods of increased sand supply at ca 3 5 ka and ca 1 7 ka the most volumetrically dominant phase of dune growth began ca 1 0 ka and continued intermittently for about 500 years it may have begun due to the combined effects of a high lake phase potential changes in lake hydrodynamics with final isostatic separation of lake superior from lakes michigan and huron and increased drought and hydrologic variability associated with the medieval warm period thus this latest eolian phase likely reflects multiple processes associated with great lakes water level and climate variability that may also explain older eolian depositional events comparison of arcadia ages and calendar corrected 14c ages from previous studies indicate broad chronological agreement between events at all sites although it appears that dune growth began later at arcadia

holocene eolian activation as a proxy for broad scale landscape change on the gila river indian community arizona abstract eolian sediments are common within the middle gila river valley southern arizona and reflect variability in eolian and fluvial processes during the late holocene this study focuses on deciphering the stratigraphic record of eolian deposition and associated luminescence dating of quartz extracts by single aliquot regeneration sar protocols stratigraphic assessment coupled with luminescence ages indicates that there are four broad eolian depositional events at ca 3145 220 yr 1950 1360 yr 800 100 yr and 690 315 yr this nascent chronology correlated with regional archeological evidence and paleoclimate proxy datasets leads to two general conclusions 1 loess deposits transverse dune formation and sand sheet deposition in the late holocene are probably linked to flow variability of the gila river though the last two events are concordant with regional megadroughts and 2 the stability of eolian landforms since the 19th century reflects the lack of eolian sediment supply during a period of fluvial incision resulting in entisol formation on dunes the prime catalyst of eolian activity during the late holocene is inferred to be sediment supply driven by climate periodicity and variable flow within the gila river catchment

late quaternary eolian sand depositional record for southwestern kansas landscape sensitivity to droughts abstract eolian deposits and landforms are ubiquitous in western kansas particularly south of the arkansas river with the presence of a stabilized dune field stratigraphic studies and associated optical dating reveal a complex depositional history for this dune field spanning the late quaternary the oldest eolian deposits from ca 16 to 12 ka completely or partially bury high terraces with ages of ca 16 and 33 ka it is unknown whether these eolian deposits reflect regional aridity and or a change in sediment availability with the transition of the arkansas river from a single channel to a braided system there is pervasive evidence for episodic eolian erosion and deposition ca 9 8 to 6 3 ka generally coincident with loess deposition on upland surfaces olson c g nettleton w d porter d a brasher b r 1997 middle holocene aeolian activity on the high plains of west central kansas holocene 7 3 255 261 and thus it is inferred to reflect regional aridity sites within the dune field show a sequence of eolian sands and weak buried soils reflecting either dune migration or sand sheet accretion at ca 1490 430 380 320 180 and 70 yr ago which correspond well with continental scale droughts in the tree ring record eolian sand in the arkansas river dune field may be derived principally with variability in fluvial activity and in climate during the late pleistocene to the middle holocene with substantial reactivation of eolian systems during decadal scale drought variability in the past 2000 yr

soil genesis optical dating and geoarchaeological evaluation of two upland alfisol pedons within the tertiary gulf coastal plain abstract much of the gulf coastal plain is mantled by sandy a and e soil horizons overlying finer grained bt horizons researchers have applied optical stimulated luminescence osl dating to a variety of depositional settings such as hillslopes and terraces in an attempt to understand depositional versus pedogenic origins of the sandy horizons and archaeological burial processes these investigations have documented a range of integrity conditions from pristine to highly bioturbated however little work has been conducted in upland summits thus we integrated field morphological descriptions constituent mass balance reconstruction and optical dating to reconstruct the timing and pedogenic pathways of two summit alfisols on the tertiary gulf coastal plain in texas investigations reveal that the sandy a and e horizons and the bt horizons in each pedon are genetically related with textural contrasts resulting from pedogenic processes optical dating revealed highly complex age structures strongly influenced by bioturbation weathering and the presence of coarse clay plus total silt particle sizes pedogenic mixing is extensive in the a and e horizons which effect apparent osl ages

episodic late holocene dune movements on the sand sheet area great sand dunes national park and preserve san luis valley colorado usa abstract the great sand dunes national park and preserve gsdnpp in the san luis valley colorado contains a variety of eolian landforms that reflect holocene drought variability the most spectacular is a dune mass banked against the sangre de cristo mountains which is fronted by an extensive sand sheet with stabilized parabolic dunes stratigraphic exposures of parabolic dunes and associated luminescence dating of quartz grains by single aliquot regeneration sar protocols indicate eolian deposition of unknown magnitude occurred ca 1290 940 715 80 320 30 and 200 120 yr ago and in the 20th century there are 11 drought intervals inferred from the tree ring record in the past 1300 yr at gsdnpp potentially associated with dune movement though only five eolian depositional events are currently recognized in the stratigraphic record there is evidence for eolian transport associated with dune movement in the 13th century which may coincide with the great drought a 26 yr long dry interval identified in the tree ring record and associated with migration of anasazi people from the four corners areas to wetter areas in southern new mexico this nascent chronology indicates that the transport of eolian sand across san luis valley was episodic in the late holocene with appreciable dune migration in the 8th 10 13th and 19th centuries which ultimately nourished the dune mass against the sangre de cristo mountains

dating recent colluvial sequences with 210pb and 137cs along an active fault scarp the eliki fault gulf of corinth greece reliable dating is an essential element of palaeoseismological studies yet whilst a suite of geochronological methods can now provide late quaternary age control it remains very difficult to date modern events i e those occurring within the last 150 years this is significant because the starting point for many palaeoseismological investigations is a modern surface rupturing event whose geological effects need to be disentangled in trench stratigraphies from palaeoseismic ruptures two dating methods which in combination can provide robust dating control in recently deposited sediments are the 210pb and 137cs dating methods here we test the applicability of using 210pb and 137cs to date colluvial sediments exposed in three trenches excavated across an earthquake fault the eliki fault gulf of corinth greece which ruptured in an earthquake in 1861 the 210pb and 137cs profiles observed in these colluvial sequences are relatively erratic due to the mixed nature of the sediments i e their deposition in an environment where the supply of slope sediments is driven by seasonal rainfall causing non uniform sediment accretion and sediment reworking in one trench however 210pb dating corroborated by 137cs dating indicates that a proposed post 1861 surface colluvial unit has been deposited over the period 1950 ad present at a rate of ca 9 mm year and overlies a significantly older unit 120 years old the dating control provided here by 210pb and 137cs dating corroborates the published interpretation of the trench stratigraphy and refines the 14c based estimated dates for the upper unit at two other trenches 210pb and 137cs dating only provided minimum ages based on the presence or absence of 210pbexcess and 137cs such approximate ages however may still useful in corroborating interpretations made using the trench stratigraphy or at sites which have long earthquake recurrence intervals determining which earthquake event was responsible for a particular bed offset

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

reconstruction of holocene coastal foredune progradation using luminescence dating an example from the świna barrier southern baltic sea nw poland abstract two sandy spits on the wina barrier wolin and uznam provide a very detailed succession of holocene coastal foredunes and dunes and are regarded as key sites along the southern baltic sea coast optically stimulated luminescence osl dating is proven to be a powerful tool for the reconstruction of holocene coastal spit evolution and foredune accretion quartz extracted from the coastal sediments in the study area provides excellent properties for osl dating the osl age from the innermost dune indicates that spit development of the wina barrier started immediately after rapid sea level rise of the littorina transgression decelerated at 6 6 ka a significant change in the foredune progradation rate occurred during the late subatlantic transgression at 1 2 ka 800 ad when migration rates decreased from 2 6 0 7 m a 1 to 1 3 0 4 m a 1 progradation accelerated again during the little ice age between 1550 and 1850 ad the systematic dating of 28 samples reveals six hiatuses during foredune succession at 2100 bc 900 bc 200 bc 200 ad 600 ad 1000 ad and 1600 ad the timing of these hiatuses correlates with the phases of transgressive dune development in the surrounding area troszyn and wina and with phases of increased aeolian activity in other parts of north and west europe we conclude that four of these phases of foredune erosion instability and aeolian sediment mobilisation were caused by general climate shifts to cooler and stormier conditions at 2200 bc 900 bc 600 ad and at 1600 ad the latter corresponding to the little ice age the period of increased aeolian activity around 1000 ad is probably to a phase of intensive forest clearance in central europe in contrast the systematic foredune accretion and foredune plain growth correlates to periods of positive sediment budget milder and calmer climate and an intact vegetation cover

stratigraphy of the kazusa group boso peninsula an expanded and highly resolved marine sedimentary record from the lower and middle pleistocene of central japan major climatic reorganizations including changes in the nature of glacial interglacial cycles through the pleistocene are a key issue for improving the understanding of earth s climate system highly resolved marine sedimentary records are essential to reconstruct the details of these past climatic changes and investigate the mechanisms responsible for them the kazusa group located in the central part of the japanese island chain is well exposed and contains a remarkably continuous and thick deep and shallow water marine sedimentary succession this group also contains well preserved marine microfossils pollen paleomagnetic reversal events geochemical signatures and a large number of tephra beds these features allow us to establish a robust chronological and stratigraphic framework for the kazusa group and provide a rare opportunity to study oceanic and terrestrial climatic and environmental changes at high resolution especially through the lower and lower middle pleistocene in the boso peninsula chiba prefecture the kazusa group is deeply incised yielding spectacular river cut exposures the matuyama brunhes paleomagnetic reversal is observed immediately above the widespread byakubi e byk e tephra in the chiba composite section within the kokumoto formation kazusa group because the matuyama brunhes boundary customarily serves as the primary guide for the lower middle pleistocene subseries boundary the chiba composite section is considered an excellent candidate for its global boundary stratotype section and point gssp this study reviews the published data for the kazusa group hitherto almost exclusively in japanese in order to place the chiba composite section within its broader depositional and chronostratigraphic context

optically stimulated luminescence dates for late pleistocene and holocene sediments from norre lyngby northern jutland denmark quartz from late pleistocene marine and freshwater deposits of known 14c age and from a historically dated aeolian deposit has been studied using multiple aliquot and single aliquot protocols comparisons are presented between equivalent doses derived using a multiple aliquot additive dose thermoluminescence approach and three osl protocols single aliquot regeneration and added dose sara mejdahl and botter jensen 1994 single aliquot additive dose murray et al 1997 and single aliquot regenerative dose murray and roberts 1998 dose rates determined by laboratory gamma spectrometry are compared with both field gamma scintillation measurements and laboratory beta thermoluminescence dosimetry measurements the agreement is satisfactory the resulting dates are discussed in terms of absolute chronology and bleaching environment

formation of linear and parabolic dunes on the eastern snake river plain idaho in the nineteenth century abstract geomorphic and stratigraphic evidence show periods of distinct hydrologic excess and deficit sometime in the past 500 years on the eastern snake river plain natural exposures at the current shore of mud lake contain a lacustrine silty sand beneath eolian sands the latter deposit is expressed at the surface as hairpin parabolic and linear dunes these dunes can be traced into and across lakes a clear sign of recent aridity two shallow water gastropods and two wood fragments from the lacustrine silty sand yield the respective ams 14 c ages of ca 705 and 988 year bp and 195 and 305 year bp the offset in ages indicates a lake hard water effect of aquatic gastropods with the wood ages providing the closest age constraint optically stimulated luminescence single aliquot regeneration ages of 150 30 and 120 20 year bp on quartz grains from the overlying eolian sands further constrains a drop in lake level and subsequent aridity to the 19th century this lacustrine dune sequence is probably the geomorphic expression of a distinct wet period followed by a severe drought between ad 1845 and 1856 which has been documented in the dendroclimatic records for the rocky mountains and the western great plains lake fluctuations and dune formation is associated with greater subdecadal variability in spring precipitation than recorded in the past 100 years

optically stimulated luminescence dating of late holocene raised strandplain sequences adjacent to lakes michigan and superior upper peninsula michigan usa this study evaluates the accuracy of optically stimulated luminescence to date well preserved strandline sequences at manistique thompson bay lake michigan and tahquamenon and grand traverse bays lake superior that span the past 4500 yr the single aliquot regeneration sar method is applied to produce absolute ages for littoral and eolian sediments sar ages are compared against ams and conventional 14 c ages on swale organics modern littoral and eolian sediments yield sar ages b100 yr indicating near if not complete solar resetting of luminescence prior to deposition beach ridges that yield sar ages b2000 yr show general agreement with corresponding 14 c ages on swale organics significant variability in 14 c ages n2000 cal yr b p complicates comparison to sar ages at all sites however a sar age of 4280 f 390 yr uic913 on ridge77 at tahquamenon bay is consistent with regional regression from the high lake level of the nipissing ii phase ca 4500 cal yr b p sar ages indicate a decrease in ridge formation rate after 1500 yr ago likely reflecting separation of lake superior from lakes huron and michigan this study shows that sar is a credible alternative to 14 c methods for dating littoral and eolian landforms in great lakes and other coastal strandplains where 14 c methods prove problematic

climatic control on quaternary fluvial sedimentology of a fenland basin river england understanding and interpreting climate response from ancient fluvial deposits requires a combined approach of detailed sedimentological description and interpretation local climate proxies and the accurate comparison of these sequences with further independent climate records application of these multiple lines of evidence is particularly effective in the quaternary period where higher resolution and more detailed palaeoenvironmental reconstruction are possible this paper presents results from a devensian weichselian age sequence in northern fenland england that integrates these approaches detailed sedimentological description has identified three fluvial facies associations overlain by a period of ice wedge cast formation fossil plant and coleopteran material within these sediments have been studied to provide palaeoenvironmental reconstructions for the local landscape including quantitative temperature estimates using the mutual climatic range method on fossil coleoptera in addition joint application of radiocarbon and optically stimulated luminescence osl dating allows this sequence to be compared with the stacked marine isotope record although dates do not agree well at the limit of the radiocarbon technique sedimentological interpretations palaeoenvironments and global ice volume variations a proxy for climatic severity are all in agreement and show clearly how the river nene responded to subtle changes in climate and vegetation cover during the devensian weichselian stage the level of detail possible in this reconstruction shows the importance of this approach in understanding fluvial response to past climate changes

residual luminescence signals in modern coastal sediments abstract modern sediments from coastal and near coastal environments in england and wales had their equivalent doses eds determined using single aliquot additive dose infra red stimulated luminescence irsl certain samples were also investigated using multiple aliquot methods for irsl green light stimulated luminescence glsl and thermoluminescence tl and also single aliquot glsl only one modern sample had its irsl signal reduced to give a zero ed those which had been deposited through turbid water columns had significant signal remaining for all stimulation methods although the glsl and irsl eds were lower than the tl analogous buried samples were also dated and findings were compared with the available age control and the modern results where a tl as well as an irsl ed was obtained for one such sample it was found to be considerably higher suggesting that the bleaching environment had been poor an unbleached residual signal in these samples could not be detected however and the dates reflected the age control the selection of a water content for use in dating was found to be critical in environments with such naturally high and variable water contents

limits to resolving catastrophic events in the quaternary fluvial record a case study from the nene valley northamptonshire uk flood events within rivers are responsible for much erosion and deposition thus deposits laid down during floods could potentially comprise the bulk of the quaternary fluvial record however it is difficult to detect individual flood events as effectively illustrated by the middle devensian weichselian to holocene fluvial sequence from the nene valley northamptonshire described in this paper this is due to limits in the resolution of sedimentological palaeontological and geochronological techniques geochronological techniques have the highest resolution but error bars of c 50 years radiocarbon and up to 2 ka optically stimulated luminescence in the late glacial do not allow detection of floods lasting only a few weeks or less geochronology is however essential for linking periods of fluvial deposition to climatic phases at the marine isotope substage scale thus multiple age determinations show remnant middle devensian deposits within a facies association mainly of younger dryas age showing similar fluvial response to climate during both time periods palaeontological assemblages suggest that climate was also similar although with some subtle differences determining average fluvial activity in response to broad climate phases improves understanding of how rivers behave over long time periods even though determination of the role of flood events in the quaternary fluvial record remains elusive

an optical luminescence chronology for late pleistocene aeolian activity in the colombian and venezuelan llanos the lowland savannas llanos of colombia and venezuela are covered by extensive aeolian landforms for which little chronological information exists we present the first optically stimulated luminescence osl age constraints for dunes in the llanos orientales of lowland colombia and new ages for dunes in the venezuelan llanos the sampled dunes are fully vegetated and show evidence of post depositional erosion ages range from 4 5 0 4 to 66 4 ka with the majority dating to 27 10 ka marine isotope stage 2 some dunes accumulated quickly during the last glacial maximum although most were active 16 10 ka accretion largely ceased after 10 ka all dunes are elongated downwind from rivers parallel with dry season winds and are interpreted as source bordering features as they are presently isolated from fluvial sediments by gallery forest it is proposed that activity was associated with a more prolonged dry season which restricted gallery forest leading to greater sediment availability on river shorelines such variability in dry season duration was potentially mediated by the mean latitude of the itcz the cessation of most dune accretion after ca 10 ka suggests reduced seasonality and a more northerly itcz position consistent with evidence from the cariaco basin