air sea temperature decoupling in western europe during the last interglacial glacial transition between 80 000 and 70 000 years ago climate cooled and ice sheets in the high northern latitudes expanded pollen and microfossil data from marine sediments indicate that an increasing thermal gradient between cold air and warmer oceans could have supported continental ice growth

occurrence stratigraphy and geochemistry of late quaternary tephra layers in the aegean sea and the marmara sea abstract several discrete tephra layers occur in 2 5 10 3 m long cores from the aegean sea whereas a single tephra is identified in 3 5 9 7 m long cores from the marmara sea major and trace element data on these tephras delineate eight distinct groups the geochemical data and multivariate statistics allow the correlation of the tephra layers with six previously described marine tephras from the eastern mediterranean sea potential terrestrial sources are suggested for the others the chronostratigraphy of the tephra layers was established using several radiocarbon dates and the oxygen isotope stratigraphy from two long piston cores four widespread tephra layers occur within the upper quaternary sediments of the aegean sea the two youngest widespread tephra layers were derived from the santorini volcano of south central aegean sea z2 the minoan eruption ca 3 6 ka and y2 the cape riva eruption ca 21 7 ka the y2 tephra is also identified in three piston cores from the marmara sea the two older widespread tephra layers originated from the eruptions which emplaced the campanian ignimbrite of the italian volcanic provinces i e the y5 tephra ca 39 3 ka and from the nisyros volcano of the southeastern aegean sea the consistent occurrence of the nisyros tephra below the y5 tephra confirms similar findings in a lake core on the island of lesbos linear extrapolations using the oxygen isotope stratigraphy suggest an age of 42 44 ka for the nisyros eruption three additional tephra layers with a limited regional distribution are identified in the aegean sea cores two of these tephras originated from the yali volcano of the southeastern aegean sea and from the aeolian islands i e x1 tephra a series of six mugearite tephra beds in the south skiros basin is interpreted as a set of redeposited turbidites

distal tephra record for the last ca 105 000 years from core prad 1 2 in the central adriatic sea implications for marine tephrostratigraphy abstract core prad 1 2 located on the western flank of the mid adriatic deep contains a continuous sediment record extending back to upper mis 11 the upper part of the record which spans the mid holocene to mis 5 4 the last ca 105 000 years has been investigated for tephra content a total of 25 discrete tephra layers were discovered only one of which was visible in the core sequence the other 24 are not visible to the naked eye nor were the majority detected by routine down core scanning methods a total of 625 geochemical measurements obtained from individual glass shards using wds epma enabled 21 of the 25 tephras to be assigned to known volcanic events emanating from the campanian province campi flegrei somma vesuvius and ischia island the results provide an independent basis for establishing an age depth profile for the upper part of the prad 1 2 record this study demonstrates that the number of non visible tephra layers can significantly exceed the number of visible layers in some deep marine sequences routine testing for the presence of non visible tephra layers can therefore prove rewarding leading to the detection of additional isochrons for dating and correlating marine sequences and for their synchronisation with terrestrial records

a new contribution to the late quaternary tephrostratigraphy of the mediterranean aegean sea core lc21 tephra layers preserved in marine sediments can contribute to the reconstruction of volcanic histories and potentially act as stratigraphic isochrons to link together environmental records recent de velopments in the detection of volcanic ash tephra at levels where none is macroscopically visible so called crypto tephra have greatly enhanced the potential of tephrostratigraphy for synchronising environmental and archaeological records by expanding the areas over which tephras are found in this paper crypto tephra extraction techniques allow the recovery of 8 non visible tephra layers to add to the 9 visible layers in a marine sediment core lc21 from the se aegean sea to form the longest single core record of volcanic activity in the aegean sea using a novel shard specific methodology sources of the tephra shards are identified on the basis of their major and trace element single shard geochemistry by comparison with geochemical data from proximal mediterranean volcanic stratigraphies the results indicate that the tephra layers are derived from 14 or 15 separate eruptions in the last ca 161 ka bp 9 from santorini 2 or 3 from kos yali or nisyros 2 from the campanian province and one from pan telleria the attributions of these tephra layers indicate that 1 inter plinian eruptions from santorini may have produced regionally significant tephra deposits 2 marine tephrostratigraphies can provide unique and invaluable data to eruptive histories for island volcanoes and 3 tephra from both pantelleria and campania may be used to correlate marine records from the aegean sea to those from the tyrrhenian adriatic and ionian seas

climate and human environment relationships on the edge of the tenaghi philippon marsh northern greece during the neolithization process abstract palynological and sedimentological investigations carried out around the tell of dikili tash eastern macedonia greece one of the oldest neolithic sites in europe improve our understanding of the evolution of the paleoenvironment from the late pleistocene to the neolithic period 6500 3200 cal bc in this region while global climate reconstructions researches based on the study of the tenaghi philippon pollen record located 5 8 km from the tell have focused on forces that drive the environment at regional or global scales we attempt to use the sediment archives on the edge of the marsh to describe the context of the neolithization process and related environmental changes our aim is to provide new data on environmental change during the early holocene by combining pollen non pollen palynomorphs npps and sedimentological analyses to be compared with archaeological information the data give an overview of the original environment prior to the neolithic and thereafter a comprehensive view of the first human impacts on the vegetation cover in local lowland areas two new pollen records located respectively 1 75 km dik4 and 150 m dik12 from the archaeological site provide the first evidence of human agropastoral activities on the landscape associated with the early neolithic communitiessince at least 6400 cal bc largely earlier than observed in the reference pollen diagram in the tenaghi philippon marsh which shows a first human impact from the second millennium cal bc admittedly such impact on the local area around the site cannot be extrapolated to a regional scale raising question of the spatial representativeness of the previous records it also shows the need to develop multi scalar investigations to assess the impact of climatic change and human activities on the landscape during the earliest phase of the neolithic settlement in southeastern balkans

geochemical properties and environmental impacts of seven campanian tephra layers deposited between 40 and 38 ka bp in the varved lake sediments of lago grande di monticchio southern italy abstract we present the results of new tephrostratigraphical and environmental impact studies of the 40 38 ka varved sediment section of lago grande di monticchio southern italy the sediments in this time zone are correlated with the heinrich h4 stadial that occurred between greenland interstadials gi 9 and gi 8 and include the widespread campanian ignimbrite ci 39 3 ka as a thick tephra layer in the middle of the h4 stadial the ci in the monticchio record is overlain by the schiava tephra from vesuvius c 1240 varve years younger than the ci and preceded by four tephras from small scale eruptions of the phlegrean fields and by an ischia derived tephra the four phlegrean field derived tephras were deposited 600 varve years or fewer prior to the deposition of the ci and show very similar major minor and trace element glass compositions to those of the ci this close similarity in composition and age could compromise the accurate linking and synchronisation of palaeoenvironmental records in the central mediterranean area microfacies analyses and xrf core scanning were used to characterise primary and secondary depositional features of all seven tephra layers and to evaluate environmental and ecological responses after tephra deposition higher concentrations of tephra derived material mainly glass shards and pumices in primary and reworked layers were detected by elevated k counts in xrf elemental core scans reworked tephra derives mainly from in washing from the littoral zone and the catchment and occurs within five to 30 years and up to 1240 varve years after the deposition of thinner 1 5 mm and thicker 5 230 mm tephra fallout deposits respectively an obvious response of diatom population growth directly after the primary tephra deposition was observed for the thicker tephra layers 1 mm during the first 1 8 years after deposition of the primary deposit indicating that the additional input of potential nutrients glass shards temporarily affected the ecological lake system

revised chronology of the sulmona lacustrine succession central italy we present new stratigraphic palaeomagnetic 87sr 86sr and 40ar 39ar data from a lacustrine succession of the sulmona basin central italy which according to an early study included six unconformity bounded lacustrine units from sul6 oldest to sul1 youngest spanning the interval 600 to 2 ka the results of the present study on the one hand confirm some of the previous conclusions but by contrast reveal that units sul2 and sul1 previously attributed to the holocene are actually equivalent to the older sul6 and sul5 units here dated to 814 530 ka and 530 457 ka respectively and that the u series dates previously published for both former sul2 and sul1 units yielded abnormally young ages in light of the present results a reassessment of the chronology of the sulmona basin succession and a revision of the tephrostratigraphy of the sul2 sul6 and sul1 sul5 units is in order copyright 2013 john wiley sons ltd

the late mis 5 mediterranean tephra markers a reappraisal from peninsular italy terrestrial records abstract we present new tephrostratigraphic records from the late mis 5 ca 110 80 ka terrestrial sediments from southern and central italy on the one hand the central italy record consists of an outcropping lacustrine sequence from the sulmona intermountain basin that contains four trachytic phonolitic tephra layers pop3 pop2a pop2b pop1 all of which show a k alkaline affinity that is typical for the roman co magmatic province the pop3 and pop1 layers were dated by 40 ar 39 ar method at 106 2 1 3 ka 2 and 92 4 4 6 ka 2 respectively the sequence in southern italy on the other hand is represented by post tyrrhenian coastal deposits of the cilento area campania which contain two trachytic layers cil2 cil1 that show the same k alkaline affinity based on their chemical compositions and radiometric ages pop3 and pop1 are firmly correlated with the marine tephra layers x 5 105 2 ka and c 22 ca 90 ka which in turn match tephras tm 25 and tm 23 11 respectively in the lacustrine sequence of lago grande di monticchio southern italy of note the pop1 layer also matches the adriatic sea tephra prad 2517 that was previously correlated with the older x 5 layer the tephra couplet pop2a and pop2b ca 103 and 103 5 ka extrapolated ages are compatible with the tm 24b and tm 24 3 tephras in monticchio which match both the stratigraphic positions and the chemical compositions in the cilento area as well as the already described x 6 layer ca 108 ka cil2 we recognise a new stratigraphic superimposed layer cil1 that matches the pop3 tm 25 c 27 x 5 mediterranean marker s in summary the data presented here provide new chemical and 40 ar 39 ar chronological constraints towards a robust late mis 5 tephrostratigraphy of the central mediterranean although at the same time they also reveal how the tephrostratigraphy itself might be flawed when dealing with tephra markers that are not adequately constrained and characterised

lateglacial and holocene vegetation dynamics in the aegean region an integrated view based on pollen data from marine and terrestrial archives to elucidate the vegetation dynamics in the aegean region during the last 20 kyr we have studied terrestrial palynomorphs in marine core geotu sl152 mount athos basin northern aegean sea at centennial scale 125 to 300 yr resolution the robust chronology of the core allows us to reliably date signals of short term vegetation change in the aegean region for the pleniglacial interval until 14 6 kyr bp our data document steppe vegetation suggesting dry climatic conditions in the borderlands of the aegean sea subaerially exposed parts of the shelf were probably colonized by pinus dominated vegetation until shelf areas were flooded during lateglacial sea level rise the final rapid decrease of pinus pollen percentages between 14 and 13 kyr bp appears to be connected to meltwater pulse mwp 1a the lateglacial interstadial complex ie meiendorf bolling and allerod is characterized by the spread of oak trees but also by the continuous presence of steppe elements indicating only slightly increas

first evidence of a distal early holocene ash layer in eastern mediterranean deep sea sediments derived from the anatolian volcanic province article i nfo a hitherto unknown distal volcanic ash layer has been detected in a sediment core recovered from the southeastern levantine sea eastern mediterranean sea radiometric stratigraphic and sedimentological data show that the tephra here termed as s1 tephra was deposited between 8970 and 8690 cal yr bp the high silica rhyolitic composition excludes an origin from any known eruptions of the italian aegean or arabian volcanic provinces but suggests a prevailing central anatolian provenance we compare the s1 tephra with proximal to medial distal tephra deposits from well known mediterranean ash layers and ash fall deposits from the central anatolian volcanic field using electron probe microanalyses on volcanic glass shards and morphological analyses on ash particles we postulate a correlation with the early holocene dikkartin dome eruption of erciyes dag volcano cappadocia turkey so far no tephra of the central anatolian volcanic province has been detected in marine sediment archives in the eastern mediterranean region the occurrence of the s1 tephra in the south eastern part of the levantine sea indicates a wide dispersal of pyroclastic material from erciyes dag more than 600 km to the south and is therefore an important tephrostratigraphical marker in sediments of the easternmost mediterranean sea and the adjacent hinterland

the intav intercomparison of electron beam microanalysis of glass by tephrochronology laboratories results and recommendations abstract the international focus group on tephrochronology and volcanism intav of the international union for quaternary research inqua has conducted an intercomparison of tephrochronology laboratories with electron beam microanalytical data on volcanic glasses submitted from 27 instruments at 24 institutions in 9 countries this assessment includes most active tephrochronology laboratories and represents the largest intercomparison exercise yet conducted by the tephrochronology community the intercomparison was motivated by the desire to assess the quality of data currently being produced and to stimulate improvements in analytical protocols and data reporting that will increase the efficacy of tephra fingerprinting and correlation participating laboratories were each supplied with a mount containing three samples for analysis 1 rhyolitic lipari obsidian id3506 2 phonolitic sheep track tephra from mt edziza british columbia canada and 3 basaltic laki 1783 a d tephra a fourth sample rhyolitic old crow tephra was also distributed most laboratories submitted extensive details of their analytical procedures in addition to their analytical results most used some combination of defocused or rastered beam and modest beam current to reduce alkali element migration approximately two thirds reported that they routinely analyze one or more secondary standards to evaluate data quality and instrument performance despite substantial variety in procedures and calibration standards most mean concentrations compare favorably between laboratories and with other data typically four or fewer data contributions had means for a given element on a given sample that differed by more than 2 standard deviations from the overall means obtaining accurate na 2 o concentrations for the phonolitic tephra proved to be a challenge for many laboratories only one half of the data sets had means within 1 standard deviation of the 8 2 wt na 2 o value obtained by other methods one mean is higher and 14 are lower three of the data set means fall below 7 wt na 2 o most submissions had relative precision better than 1 5 for the major elements for low abundance elements the precision varied substantially with relative standard deviations as small as 10 and as large as 110 because of the strong response to this project the tephrochronology community now has a large comparative data set derived from common reference materials that will facilitate improvements in accuracy and precision and which can enable improved use of published data produced by the participating laboratories finally recommendations are provided for improving accuracy precision and reporting of electron beam microanalytical data from glasses

marine tephra from the cape riva eruption 22 ka of santorini in the sea of marmara abstract a discrete tephra layer has been discovered in three marine sediment cores from the sea of marmara eastern mediterranean the rhyodacitic glass chemistry and the stratigraphical position suggest a santorini provenance and in particular a correlation with the marine y 2 tephra that is known from the southern aegean sea and eastern levantine basin this tephra represents the distal facies of the cape riva eruption of santorini which has been dated by 14c on land at 21 950 cal yr bp hitherto the y 2 tephra has been detected only in marine sediment cores recovered south to southeast of its volcanic source the new occurrence in the sea of marmara approximately 530 km nne of the santorini eruptive centre suggests a more north easterly dispersal of fallout products of the cape riva eruption than previously supposed

800 000 years of abrupt climate variability we constructed an 800 000 year synthetic record of greenland climate variability based on the thermal bipolar seesaw model our greenland analog reproduces much of the variability seen in the greenland ice cores over the past 100 000 years the synthetic record shows strong similarity with the absolutely dated speleothem record from china allowing us to place ice core records within an absolute timeframe for the past 400 000 years hence it provides both a stratigraphic reference and a conceptual basis for assessing the long term evolution of millennial scale variability and its potential role in climate change at longer time scales indeed we provide evidence for a ubiquitous association between bipolar seesaw oscillations and glacial terminations throughout the middle to late pleistocene

sedimentation processes in the eastern mediterranean sea during the late glacial and holocene revealed by end member modelling of the terrigenous fraction in marine sediments we present grain size distributions of the terrigenous fraction of two sediment cores from the southeast levantine sea sl112 and the northern aegean sea sl148 spanning the time interval from the late glacial to the present end member modelling of the grain size distribution allows discriminating between aeolian and fluvial transport of the sediments and helps to infer palaeoenvironmental conditions in the source areas sedimentary and depositional processes during the late glacial and holocene were controlled by climatic variations of both the northern high latitudes and the african climate system the sedimentation at site sl112 off israel is dominated by the suspension load of the river nile and aeolian dust from the sahara variations in grain size reflect the early to mid holocene climate transition from the african humid period to recent arid conditions this climate change was gradual in contrast to the abrupt humidity change documented in western saharan records this implies a successive decrease in nile river sediment supply due to a step wise aridification of the headwaters the grain size data of sl112 show a humidity maximum at 5 kyr bp coincident with a regionally restricted wet phase in the levantine sea the sediments at the north aegean site sl148 consist of riverine particles and low amounts of aeolian dust probably derived from south european sources and with probably minor saharan influence the sedimentation processes are controlled by climate conditions being characterized by enhanced deposition of dust during the cold and dry glacial period and by decreased aeolian influx during the temperate and humid holocene

the reset project constructing a european tephra lattice for refined synchronisation of environmental and archaeological events during the last c 100 ka this paper introduces the aims and scope of the reset project response of humans to abrupt environmental transitions a programme of research funded by the natural environment research council uk between 2008 and 2013 it also provides the context and rationale for papers included in a special volume of quaternary science reviews that report some of the project s findings reset examined the chronological and correlation methods employed to establish causal links between the timing of abrupt environmental transitions aets on the one hand and of human dispersal and development on the other with a focus on the middle and upper palaeolithic periods the period of interest is the last glacial cycle and the early holocene c 100 8 ka during which time a number of pronounced aets occurred a long running topic of debate is the degree to which human history in europe and the mediterranean region during the palaeolithic was shaped by these aets but this has proved difficult to assess because of poor dating control in an attempt to move the science forward reset examined the potential that tephra isochrons and in particular non visible ash layers cryptotephras might offer for synchronising palaeo records with a greater degree of finesse new tephrostratigraphical data generated by the project augment previously established tephra frameworks for the region and underpin a more evolved tephra lattice that links palaeo records between greenland the european mainland sub marine sequences in the mediterranean and north africa the paper also outlines the significance of other contributions to this special volume collectively these illustrate how the lattice was constructed how it links with cognate tephra research in europe and elsewhere and how the evidence of tephra isochrons is beginning to challenge long held views about the impacts of environmental change on humans during the palaeolithic

acigol rhyolite field central anatolia part 1 high resolution dating of eruption episodes and zircon growth rates protracted pre eruptive zircon residence is frequently detected in continental rhyolites and can conflict with thermal models indicating briefer magma cooling durations if scaled to erupted volumes here we present combined u th and u th he zircon ages from the acigol rhyolite field central anatolia turkey which is part of a quaternary bimodal volcanic complex unlike other geochronometers this approach dates crystallization and eruption on the same crystals allowing for internal consistency testing despite the overall longevity of acigol rhyolite volcanism and systematic trends of progressive depletion in compatible trace elements and decreasing zircon saturation temperatures we find that zircon crystallized in two brief pulses corresponding to eruptions in the eastern and western part of the field during middle and late pleistocene times respectively for late pleistocene zircon resolvable differences exist between interior average 30 7 0 9 ka 1 error and rim 21 9 1 3 ka crystallization ages these translate into radial crystal growth rates of 10 13 to 10 14 cm s broadly consistent with those constrained by diffusion experiments rim crystallization and u th he eruption ages 24 2 0 4 ka overlap within uncertainty evidence for brief zircon residence at acigol contrasts with many other rhyolite fields suggesting that protracted zircon crystallization in or recycling from long lived crystal mushes is not ubiquitous in continental silicic magma systems instead the span of pre eruptive zircon ages is consistent with autochthonous crystallization in individual small volume magma batches that originated from basaltic precursors

rapid environmental changes in southern europe during the last glacial period oxygen isotope records from greenland ice cores1 2 indicate numerous rapid climate fluctuations during the last glacial period north atlantic marine sediment cores show comparable variability in sea surface temperature and the deposition of ice rafted debris3 4 5 in contrast very few continental records of this time period provide the temporal resolution and environmental sensitivity necessary to reveal the extent and effects of these environmental fluctuations on the continents here we present high resolution geochemical physical and pollen data from lake sediments in italy and from a mediterranean sediment core linked by a common tephrochronology our lacustrine sequence extends to the past 102 000 years many of its features correlate well with the greenland ice core records demonstrating that the closely coupled ocean atmosphere system of the northern hemisphere during the last glacial4 extended its influence at least as far as the central mediterranean region numerous vegetation changes were rapid frequently occurring in less than 200 years showing that the terrestrial biosphere participated fully in last glacial climate variability earlier than 65 000 years ago our record shows more climate fluctuations than are apparent in the greenland ice cores together the multi proxy data from the continental and marine records reveal differences in the seasonal character of climate during successive interstadials and provide a step towards determining the underlying mechanisms of the centennial millennial scale variability

improved age estimates for key late quaternary european tephra horizons in the reset lattice abstract the research project response of humans to abrupt environmental transitions reset used tephra layers to tie together and synchronise the chronologies of stratigraphic records at archaeological and environmental sites with the increasing importance of tephra as chronological markers in sedimentary sequences both in this project and more generally comes a requirement to have good estimates for the absolute age of these volcanic horizons this paper summarises the chronology of the key tephra in the reset tephra lattice in the time range 10 60 ka bp from the existing literature from papers produced as part of the reset project and reanalysis conducted for this paper the paper outlines the chronological approach taken to the dating of tephra within the reset project and the basis for further work as part of the intimate integrating ice core marine and terrestrial records initiative for each of the tephra layers in the lattice the existing literature is discussed and where relevant date estimates updated using the latest radiocarbon calibration curves intcal13 and marine13 and methods maps show the approximate extent of tephra finds giving a visual indication of the coverage of the lattice in different time periods

the relative motion between africa and eurasia as derived from itrf2000 and gps data 1 studies of intra and inter plate deformation typically need a model describing the motions of the stable part of the tectonic plates for reference purposes we have developed deos2k a model for the current motion of seven major tectonic plates derived from space geodetic observations this paper focuses on relative motion between africa and eurasia in the past this motion has been poorly established because of poor data coverage for africa deos2k is based on itrf2000 altamimi et al 2002 and new african gps observations it is an improvement over the nuvel 1a model for predicting the present day relative motions of these two plates deos2k predicts in northeastern africa that africa eurasia relative motion is about 40 smaller in magnitude than nuvel 1a and trends more to the northwest this is consistent with independent local geodetic observations a similar shift in orientation clockwise is observed at the western tip of the plate boundary

phase relationships between millennial scale events 64 000 24 000 years ago a core recovered on the iberian margin off southern portugal can be correlated with greenland ice cores using oxygen isotope variability in planktonic foraminifera which closely matches the ice core records of temperature over greenland our age model identifies the base of every interstadial between 64 000 and 24 000 years ago and uses the greenland ice core project grip timescale the oxygen isotope signal in benthic foraminifera on this grip based timescale is quite different from the planktonic record and resembles the temperature record over antarctica when this is synchronized with greenland using the record of methane in the atmospheric air in the polar ice cores we interpret the benthic record as indicating significant fluctuations in ice volume during millennial events and we suggest that antarctic temperature changed as a function of ice volume

climate dynamics in the borderlands of the aegean sea during formation of sapropel s1 deduced from a marine pollen record abstract to unravel the climatic and environmental dynamics in the borderlands of the aegean sea during the early and middle holocene and notably for the interval of sapropel s1 s1 formation we have analysed terrestrial palynomorphs from a marine core in the northern aegean sea the qualitative results were complemented by quantitative pollen based climate reconstructions a land sea correlation was established based on pollen data and sediment lightness measurements from the same core and previously published benthic foraminifer data from a nearby core the borderlands of the aegean sea underwent a transition from an open vegetation to oak dominated woodlands between 10 4 and 9 5 ka cal bp a coeval increase in winter precipitation suggests that moisture availability was the main factor controlling holocene reforestation the 50 higher winter precipitation during s1 formation relative to pre sapropelic conditions suggests a strong contribution from the borderlands of the aegean sea to the freshwater surplus during s1 formation the humid and mild winter conditions during s1 formation were repeatedly punctuated by short term climatic events that caused a partial deforestation and a reorganisation within the broad leaved arboreal vegetation in the marine realm these events are documented by improved benthic oxygenation the strongest event represents the regional expression of the 8 2 ka cold event and led to an interruption in s1 formation except for the interval of s1 formation the pollen derived winter temperatures correlate with the smoothed gisp2 k series they support the previously published marine based concept that the intensity of the siberian high strongly controlled the winter climate in the aegean region during s1 formation in the aegean sea however climate conditions in the borderlands were more strongly affected by the monsoonally influenced climate system of the lower latitudes

synchroneity between marine and terrestrial responses to millennial scale climatic variability during the last glacial period in the mediterranean region land sea climatic proxies have been obtained from the last glacial section of images core md95 2043 western mediterranean sea vegetation and alkenone derived sst curves indicate rapid 150 years and synchronous terrestrial and marine climatic changes paralleling the dansgaard oeschger d o climatic variability over greenland this frequency of climate change can be related to shifts between the two modes of operation of the north atlantic oscillation nao transfer functions applied to the pollen data indicate that there was an amplification of the climatic signal during heinrich events hes in comparison with other d o stadials the development and persistence of both scandinavian and atlantic mobile polar highs over southwestern europe may explain the extreme cooling 10 c and dryness 400 mm during heinrich events 5 and 4 in the mediterranean region comparison of the results of core md95 2043 with similar climatic data from images core md95 2042 located off portugal indicates that thermal and precipitation gradients occurred between the mediterranean and the atlantic sides of iberia within hes hes 4 and 5 are associated with more humid conditions in the atlantic by 200 mm than in the mediterranean site as is the case at the present time this comparison also illustrates the different behaviour of these areas during the d o stadials in contrast with the mediterranean site the atlantic site shows similar precipitation and temperature drops for all the d o stadials including those related to the hes here we propose the operation of different mobile polar highs mph as the driving mechanism for this difference in behaviour between the atlantic and mediterranean sides of iberia hes are related to a stronger influence of the scandinavian mph forcing a severe aridification and cooling of the full iberian peninsula the atlantic mph may have been dominant during the other stadials which would preferentially affect southwestern iberia

high resolution record of northern hemisphere climate extending into the last interglacial period high resolution record of northern hemisphere climate extending into the last interglacial period

the marine isotope stage 1 5 cryptotephra record of tenaghi philippon greece towards a detailed tephrostratigraphic framework for the eastern mediterranean region abstract the iconic climate archive of tenaghi philippon tp ne greece allows the study of short term palaeoclimatic and environmental change throughout the past 1 3 ma to provide high quality age control for detailed palaeoclimate reconstructions based on the tp archive crypto tephra studies of a peat core tp 2005 have been carried out for the 0 130 ka interval the results show that the tp basin is ideally positioned to receive tephra fall from both the italian and aegean arc volcanic provinces two visible tephra layers the santorini cape riva y 2 c 22 ka and the campanian ignimbrite ci y 5 c 39 8 ka tephras and six primary cryptotephra layers namely the early holocene e1 tephra from the aeolian islands c 8 3 ka the campanian y 3 c 29 ka and x 6 tephras c 109 5 ka as well as counterpart tephras tm 18 1d c 40 4 ka tm 23 11 c 92 4 ka and tm 33 1a c 116 7 ka from the lago grande di monticchio sequence southern italy were identified along with repeatedly redeposited y 2 and ci tephra material bayesian modelling of the ages of seven of the primary tephra layers 60 radiocarbon measurements and 20 palynological control points have been applied to markedly improve the chronology of the tp archive this revised chronology constrains the age of tephra tm 18 1d to 40 90 41 66 cal ka bp 95 4 range several tephra layers identified in the tp record form important isochrons for correlating this archive with other terrestrial e g lago grande di monticchio sulmona basin and lake ohrid and marine e g adriatic sea core prad 1 2 and aegean sea core lc21 palaeoclimate records in the mediterranean region

tephrostratigraphy and tephrochronology in the philippi peat basin macedonia northern hellas greece abstract three tephra layers have been identified in the upper 15 m of a 190 m section of peat beneath the philippi fen they provide significant lithological and chronological markers throughout the fen and the aegean region the upper tephra pht1 consists of shards of a transparent calcalkaline felsic glass and fragments of plagioclase augite hypersthene and rare hornblende magnetite apatite and quartz peat directly beneath pht1 gave a radiocarbon approximate age of 13 000 yr the middle tephra layer pht2 which resembles pht1 in chemistry and petrography but contains more crystals and lithic fragments rests on peat dated ca 18 000 14 c yr bp the lower tephra pht3 has colorless to brown glass shards with a trachytic chemistry and a mineral assemblage of sanidine sodic plagioclase biotite aegirine augite hornblende titanite and apatite bracketing radiocarbon ages imply that pht3 accumulated about 30 000 14 c yr bp the likely ages of pht1 and pht2 together with their mineralogical and chemical characteristics suggest that these tephras came from the volcanic field of thera in the hellenic arc pht2 particularly was derived from a major known explosive eruption ca 18 000 yr bp the cape riva eruption correlative to the y 2 tephra layer evidence for pht3 suggests derivation from the campanian province of italy and correlation with the campanian ignimbrite and the y 5 ash beneath the mediterranean sea

the drama basin water quality and peat lignite interaction the drama basin is a typical intermontane basin 2 300 km2 in northern greece filled with detrital and lacustrine sediments containing peat lignite seams in the southwestern part of the basin philippi sub basin peat accumulated practically until the present specific conductivity and ph as well as contents of major ions and trace elements have been determined in 20 surface and shallow groundwater samples collected across the basin water composition reflects the dominance of carbonate rocks in the whole basin peat oxidation and mineralization contribute to poor element enrichment of the philippi sub basin surface water derived from both the organic and inorganic peat fractions anthropogenic activities waste water effluents and rubbish dumps increase mn p b and br concentrations only mn exceeds ec recommendations 50 g l in some places there is also a slight increase in na and cl contents improving measures in the management of point pollution sources should be a priority to warrant the sustainable exploitation of water resources in the drama basin

marine continental tephra correlations volcanic glass geochemistry from the marsili basin and the aeolian islands southern tyrrhenian sea italy abstract major minor and trace element analysis of volcanic glass in proximal and distal it is evident that correlation of proximal continental and distal marine tephras at a high level of confidence requires a full complement of major minor and trace element data in conjunction with considerations of the mineralogy and morphology of juvenile deposits these data help define petrological lineages such that precise provenance can be established whilst a precise proximal distal match must be based on identical major minor and trace element concentrations it is clear that resurgent activity from a single volcano can produce magmas with identical compositions in such cases stratigraphic relationships must complement any geochemical study occasionally proximal stratigraphies may be unrepresentative of the complete eruptive history because of a lack of exposure due to burial by more recent effusive and explosive activity or sector collapse which can remove vital stratigraphy particularly on volcanic islands

distribution and chemical composition of tephra layers from eastern mediterranean abyssal sediments abstract most cores of late quaternary sediments from the eastern mediterranean sea contain many ash layers glass shards from discrete layers have been analysed chemically for major elements the layers from different cores have been correlated and unambiguously related to known volcanic events on the basis of the chemical data most of the layers are derived from explosive eruptions of the santorini volcanic complex other layers have their source in other volcanoes of the hellenic arc yali nisyros kos one layer originated from the campanian area italy

diffusive isotopic contamination of mafic magma by coexisting silicic liquid in the muskox intrusion shifts in 87 sr 86 sr and 143 nd 144 nd ratios measured in cumulates from the upper levels of the muskox mafic intrusion indicate that isotopic and bulk chemical exchange were decoupled across a mafic silicic liquid interface during crystallization of the intrusion modeling of diffusive exchange between liquid layers demonstrates that isotopic compositions of silicate liquids in layered magma chambers may be strongly affected by this process on time scales of 10 3 to 10 4 years diffusive contamination can be used to place constraints on the physical processes and time scales of magmatic systems

enhanced seasonality of precipitation in the mediterranean during the early part of the last interglacial the deposition of sapropels in the eastern mediterranean sea is thought to occur during intervals of intensified african monsoon and increased precipitation in the mediterranean borderlands speleothem and pollen records however reveal conflicting evidence for a mediterranean wide precipitation increase suggesting that seasonal changes in the hydrological regime may be important using a multiproxy record we present the first independent evidence for seasonality of precipitation during the early last interglacial ca 130 119 ka from the tenaghi philippon peatland in northeast greece during the early part of the interglacial mineralogical macrofossil and pollen records from the same core show a shift from mire to lacustrine conditions simultaneous with an expansion of sclerophyllous vegetation and the presence of acicular aragonite indicating the onset of highly evaporative summer conditions this indicates enhanced seasonality of precipitation and reconciles the apparent incongruity between mediterranean pollen and speleothem records it also provides evidence for significantly increased winter precipitation coeval with the deposition of sapropel s5 one of the most prominent sapropels of the pleistocene we suggest that in addition to the summer african monsoon component increased winter precipitation from the northern mediterranean borderlands may have contributed to maintaining reduced surface water salinities in the mediterranean sea over the entire year

rapid coupling between ice volume and polar temperature over the past 150 000 years a new approach to dating a continuous sea level record using speleothem u th ages shows that past variations in global ice volume occurred within centuries of polar climate change with rates of sea level rise reaching at least 1 metre per century

tephrostratigraphy study for the last 18 000 14 c years in a deep sea sediment sequence for the south adriatic abstract a detailed tephrostratigraphy supported by accelerator mass spectrometry ams 14c dating and isotopic and geochemical analyses has been carried out for a deep sea core collected from the southern adriatic sea which spans the last 18 14c kyr fourteen ash layers have been recognized in the marine core and the origin was determined by comparing their age and geochemistry with tephra detected in terrestrial deposits the geochemical signatures of marine ash layers indicate a prevailing campanian and subordinate etnean and eolian provenances collectively they are attributed to sources in the phlegraean fields lam lagno amendolare ln1 ln2 gm1 c 2 nyt neapolitan yellow tuff c 1 agnano pomici principali ams pf agnano monte spina ast astroni somma vesuvius l9 pomici di base l8 greenish mount etna et1 y1 biancavilla ignimbrite lipari e 1 gabellotto fiumebianco and palinuro seamount pal 1 some of these eruptions have been detected for the first time in marine cores astroni lam l9 l8 and three were detected and dated by marine tephra ln1 ln2 and pal 1 providing new more precise stratigraphic markers for the last 18 kyr in the south adriatic marine record

the formation of tephra layers in peatlands an experimental approach abstract tephrochronology provides a valuable method of dating peat deposits but results may be compromised if tephra undergoes significant post depositional movement this study takes an experimental approach to investigate the processes of tephra taphonomy tephra was applied to peats and movement monitored over periods of up to 6 years experiments combined field studies on six british peatlands with rainfall simulation experiments in the laboratory tephra moved up to 15 cm down through the peat but the vast majority remained at the surface at time of deposition forming a layer which accurately recorded the palaeo surface tephra moved both down by shards sinking through the peat and up with shards probably being moved by plant growth or with water table variability the extent of tephra movement most likely depends on the density and porosity of the surface peat there is no simple relationship with wetness there is some indication that the extent of tephra movement depends on the tephra particle size but this will require further work to confirm the taphonomy of tephra is an important issue which should be considered in all tephrochronology studies in peatlands

high resolution palynological record off the iberian margin direct land sea correlation for the last interglacial complex abstract we present high resolution pollen dinocyst and isotopic data for the last interglacial complex from marine core md952042 southwestern margin of the iberian peninsula 37 48 n 10 10 w 3148 m direct land sea correlation from this core indicates that during this period north atlantic sea surface temperatures were in phase with iberian climate our palynological analysis suggests a younger dryas like event at the marine isotope stage mis 6 5 transition the analysis also indicates that the eemian spans from the lightest isotopic values of mis 5e ca 126 ky bp to the heavier isotopic values towards the mis 5e 5d transition therefore the eemian is not entirely equivalent to mis 5e pollen analysis identifies four climatic phases of low amplitude during the eemian a mediterranean climate in southwestern europe is gradually replaced by oceanic conditions the middle of the eemian is characterized by an increase in precipitation on the land and ocean associated with a slight cooling this seems to be the result of a displacement of the polar front as far south as southern europe during this period after the eemian three relatively short climatic phases on land melisey i st germain ia and montaigu cold event occurred contemporaneously with three shifts of sea surface temperatures the montaigu event first identified in terrestrial pollen sequences is therefore also recorded in core md952042 on the basis of pollen dinocyst and planktonic isotopic data our results also show that the warm periods of mis 5 are not characterized by similar climatic conditions on land

tephrostratigraphy chronology and climatic events of the mediterranean basin during the holocene an overview the identification and characterisation of high frequency climatic changes during the holocene requires natural archives with precise and accurate chronological control which is usually difficult to achieve using only 14c chronologies the presence of time spaced tephra beds in quaternary mediterranean successions represents an additional independent tool for dating and correlating different sedimentary archives these tephra layers are potentially useful for resolving long standing issues in paleoclimatology and can help towards correlating terrestrial and marine paleoclimate archives known major tephras of regional extent derive from central and southern italy the hellenic arc and from anatolia a striking feature of major holocene tephra deposition events in the mediterranean is that they are clustered rather than randomly distributed in time several tephra layers occurred at the time of the s1 sapropel formation between c 8 4 and 9 0 ka bp mercato gabellotto fiumebianco e1 cappadocia and ot

combined marine proxy and pollen analyses reveal rapid iberian vegetation response to north atlantic millennial scale climate oscillations abstract a deep sea sediment core from the western portuguese margin has provided a continuous high resolution record of millennial scale climatic oscillations during the interval 9000 65 000 yr b p pollen analysis of the same sequence allows direct in situ assessment of the phase relationship between the north atlantic climate system and vegetation changes on the adjacent landmass this demonstrates for the first time that variability in nw iberian tree population size closely tracked millennial scale climate variability

an inter laboratory comparison of the electron probe microanalysis of glass geochemistry abstract tephrochronology commonly relies upon grain discrete analysis of glass shards to reveal the subtle geochemical differences between tephras from past explosive volcanic eruptions the use of electron probe microanalysis for this purpose is widely accepted by tephrochronologists it is widely recognised that both precision and accuracy must be maximised and that rigorous standardisation procedures must be followed in this paper the performances of seven northern european electron microprobe centres are compared using a geochemically homogeneous obsidian secondary standard the results reveal that a number of tephra oriented probe centres could benefit from exercises similar to the programme outlined within in particular it is evident that a number of these centres undertaking tephrochronological investigations have generated geochemical data that may be inadequate in terms of distinguishing between tephras inaccuracy in the determination of sodium is seen to be the main difficulty in recent years the application of distal tephrochronology to stratigraphical problems in the northern european quaternary record has become increasingly common geochemical standardisation is essential at an early stage in the development of a regional tephrochronological framework and we hope exercises such as presented here will encourage the production of reliable tephra geochemical data

identification and dating of tephra layers from quaternary sedimentary sequences of inner anatolia turkey abstract results presented here are part of a research programme to investigate the environmental evolution in central anatolia during the pleistocene in this study tephra are used as chronostratigraphical markers between lacustrine sequences studied in cores or in sections surrounding eruptive centres of the central anatolian province at different locations in the konya plain and cappadocia tephra have been identified characterized and linked to eruptions of the nearby volcanoes seven different tephra have been clearly identified in lacustrine sequences of the konya plain 14 c dates on shells or organic matter as well as 230 th 234 u ages on gypsum give a chronological framework to the tephra layers in addition the study of the sediment fill of the eski acigol maar near nevsehir has allowed the recognition of several eruptions during late glacial and holocene in the vicinity of acigol the results show the first tephra to be identified in lacustrine sequences of anatolia they also show the cappadocian volcanism to be very young 35 ka this young volcanism is often of a basaltic type and does not include thick differenciated pyroclastic deposits

the upper and lower nisyros pumices revisions to the mediterranean tephrostratigraphic record based on micron beam glass geochemistry abstract the greek island of nisyros is the source of tephra found in distal settings throughout the aegean in this contribution we define geochemical fingerprints for the lower and upper pumice eruptions of nisyros based on micron beam major empa and trace la icp ms element data these two eruptions are compositionally distinct from each other the high phenocryst content of proximal lower and upper pumice tephra means that the differences between the two magmas are masked in whole rock analyses we demonstrate that all previous reports of distal marine and continental tephras correspond to the younger upper pumice not the older lower pumice this has important implications for the marine tephrochronology of the mediterranean and for the age of the upper and lower pumice eruptions we suggest an age of at least 47 ka for the upper pumice and an older unconstrained age for the lower pumice

stratigraphy and significance of brown tuffs on the aeolian islands southern italy abstract brown tuffs bt are volcaniclastic ash deposits prominently represented in the stratigraphic profiles of all the aeolian islands and capo milazzo on the northern coast of sicily detailed stratigraphy and tephrochronology together with available radiometric ages suggest that they were emplaced over a long time interval spanning from the end of the last interglacial period ca 80 ka bp up to 4 5 ka bp age of the overlying punte nere pyroclastic products on vulcano the most complete bt succession is documented on lipari where 14 distinct and successive units are subdivided by the interbedding of widespread tephra layers local volcanic products paleosols and epiclastic deposits and the occurrence of local erosive surfaces inter island occurrence of ischia tephra a widely known tephra layer in the aeolian archipelago dated at 56 ka bp and monte guardia pyroclastics from lipari dated at 22 20 ka bp subdivides the bt succession in upper ubt intermediate ibt and lower bt units lbt which can be correlated at regional level the lbt was emplaced between 80 and 56 ka bp the ibt between 56 and 22 ka bp and the ubt between 20 and 4 5 ka bp on the basis of stratigraphy similarity in lithology and textural features morphology of glass fragments composition and consistency of thickness and grain size variations ubt units correlate with piano grotte dei rossi tuffs on vulcano island they were generated by pulsating hydromagmatic explosive activity giving rise to pyroclastic density currents spreading laterally from a source located inside the la fossa caldera on vulcano island composition is in agreement with this hypothesis since ubt compositional features match those of vulcano magmas erupted in that period the effect of co ignimbrite ash clouds or associated fallout processes from sustained eruptive columns is seen to explain the presence of ubt in areas further away from the suggested source e g salina and lipari islands and capo milazzo the origin of ubt exposed on panarea island is still a matter of debate due to contrasting compositional data due to large uniformity of lithological textural and componentry characters with respect to the ubt the lower portions of the bt succession lbt ibt are considered to be the result of recurrent large scale hydromagmatic eruptions of similar type moreover for the ibt units the correlation with monte molineddo 3 pyroclastics of vulcano island on the basis of lithological compositional and stratigraphic matching again suggests source s related to the vulcano plumbing system and located within the la fossa caldera

a new and less destructive laboratory procedure for the physical separation of distal glass tephra shards from sediments abstract tephrochronology a key tool in the correlation of quaternary sequences relies on the extraction of tephra shards from sediments for visual identification and high precision geochemical comparison a prerequisite for the reliable correlation of tephra layers is that the geochemical composition of glass shards remains unaltered by natural processes e g chemical exchange in the sedimentary environment and or by laboratory analytical procedures however natural glasses particularly when in the form of small shards with a high surface to volume ratio are prone to chemical alteration in both acidic and basic environments current techniques for the extraction of distal tephra from sediments involve the cleaning of samples in precisely such environments and at elevated temperatures the acid phase of the cleaning process risks alteration of the geochemical signature of the shards while the basic phase leads to considerable sample loss through dissolution of the silica network here we illustrate the degree of alteration and loss to which distal tephras may be prone and introduce a less destructive procedure for their extraction this method is based on stepped heavy liquid flotation and which results in samples of sufficient quality for analysis while preserving their geochemical integrity in trials this method out performed chemical extraction procedures in terms of the number of shards recovered and has resulted in the detection of new tephra layers with low shard concentrations the implications of this study are highly significant because i the current database of distal tephra records and their corresponding geochemical signatures may require refinement and ii the record of distal tephras may be incomplete due to sample loss induced by corrosive laboratory procedures it is therefore vital that less corrosive laboratory procedures are developed to make the detection and classification of distal glass tephra more secure

a 90 000 200 000 yrs marine tephra record of italian volcanic activity in the central mediterranean sea abstract a detailed tephrochronological study was undertaken in three deep sea cores collected in the tyrrhenian and ionian seas the age and the origin of the marine tephra were inferred from oxygen isotope records of foraminifera and from major element compositions of glass shards seventy one eruptions were detected in the time interval 90 000 200 000 yrs during which the volcanoes of the roman and campanian regions and of the southern italy were in activity this is attested by the consistency of the geochemical compositions of both marine and terrestrial deposits most of the marine tephra consisted in trachytes and phonolites characterizing a roman and campanian origin several tephra were proposed as key horizons for proximal and distal sediments among them one tephra originating from mount etna 149 300 yrs and five tephra from pantelleria island 130 000 yrs 163 600 yrs 192 500 yrs 197 400 yrs and 198 400 yrs were northerly dispersed several other key horizons originated from the campanian or roman provinces were detected as far as 1000 km from the vents

revised tuning of ocean drilling program site 964 and kc01b mediterranean and implications for the δ18o tephra calcareous nannofossil and geomagnetic reversal chronologies of the past 1 1 myr 1 high resolution color reflectance records of kc01 and kc01b calabrian ridge ionian sea are presented and compared with a modified spliced high resolution color reflectance record of ocean drilling program odp site 964 this comparison revealed that kc01b is characterized by intensive deformation between 27 and 28 5 m piston depth and that some sapropels are tectonically reduced in thickness moreover the piston coring has caused considerable stretching in the top of kc01 and kc01b using a new splice of odp site 964 as guide previous astronomical tuned timescales of kc01b and odp site 964 were evaluated this evaluation resulted in a new sapropel based astronomical timescale for the last 1 1 myr the new timescale implies a much more uniform change in sedimentation rate for the ionian sea cores two prominent excursions to lighter values in the 18o record of the planktonic foraminiferal species globigerinoides ruber occur during marine isotopic stages 12 and 16 applying the new timescale these shifts correspond with maxima in obliquity and are punctuated by minima in the precession cycle they are absent in global ice volume records and are interpreted as reflecting a summer low salinity surface water lens that floats on top of extremely saline intermediate and deep waters at times of the very low sea levels during these glacial periods all biostratigraphic and magnetostratigraphic events found in kc01b and odp site 964 were re dated according to the new timescale and the ages of 33 tephra layers were reviewed the new ages for the calabrian ridge 2 and 3 magnetic events in the brunhes are concordant with minima in the global sint800 composite record derived from worldwide deep sea records of relative paleointensity and have been attributed to the big lost and la palma excursions respectively

holocene seasonality changes in the central mediterranean region reconstructed from the pollen sequences of lake accesa italy and tenaghi philippon greece this study presents pollen based climate reconstructions of holocene temperature and precipitation seasonality for two high resolution pollen sequences from the central lake accesa central italy and eastern mediterranean tenaghi philippon greece regions the quantitative climate reconstruction uses multiple methods to provide an improved assessment of the uncertainties involved in palaeoclimate reconstructions the multimethod approach comprises partial least squares regression weighted average partial least squares regression the modern analogues technique and the non metric multidimensional scaling generalized additive model method we find two distinct climate intervals during the holocene the first is a moist period from 9500 to 7800 cal bp characterised by wet winters and dry summers resulting in a strongly seasonal hydrological contrast stronger than today that is interrupted by a short lived event around 8200 cal bp this event is characterised by wet winters and summers at accesa wh

33 000 yr k ar dating of the volcano tectonic horst of the isle of ischia gulf of naples the gulf of naples corresponds to a tectonic sink connected with recent volcanic activity in the south campanian area phlegrean fields ischia and vesuvius at its extreme northwest the isle of ischia was early recognized as a volcano tectonic horst by rittmann1 previous data2 concluded that its uplift ended around 300 000 yr and that the green tuff formation of which it is predominantly composed had an age of some 700 000 yr but tectonic and morphological studies together with original tephrostratigraphical observations on the slope of the horst led us to do some new k ar datings these revealed that the 780 m uplift of the horst from the sea level is younger than 33 000 yr the green tuff which was considered to be the oldest volcanic unit in the island is now dated at 56 000 yr its eruption following the dismantlement of a first volcanic complex now dated as not older than 130 000 yr

review and new aspects concerning the formation of eastern mediterranean sapropels abstract in this paper it is proposed that the formation of eastern mediterranean sapropels occurred in an anti estuarine type of circulation which was to some degree weakened relative to the present in response to reduction of the eastern mediterranean excess of evaporation over freshwater input this reduction of excess evaporation would have been imposed by intensifications of 1 the indian ocean summer sw monsoon influencing the eastern mediterranean via increased nile discharge and 2 the system of mediterranean depressions an element of the westerly atlantic system causing increased precipitation and decreased evaporation both the indian ocean summer monsoon and the westerly atlantic system would be intensified in response to the occurrence of distinct minima in the cycle of precession it is demonstrated that reduced excess evaporation whether or not coinciding with global phases of deglaciation would lead to reduction of surface water salinities in the eastern mediterranean causing isolation of previously formed high salinity cooler deep water thus mixing was severely reduced possibly even restricted to eddy diffusion with only occasional convective events that because of the existing density gradient hardly ever would reach the deepest parts of the basin the consequently diminished oxygen advection down from a few hundred meters in the water column favoured preservation of the sinking organic matter this would however suffice only to enable the formation of sapropels with low organic carbon contents the high organic carbon contents observed in various sapropels are argued to reflect superimposed increases of export production the described scenario accounts for previously reported 1 increases of organic carbon content with increasing depth of deposition within individual sapropels and 2 asymmetrical sequences of sapropel deposition characterized by gradual build up and rather abrupt ending it is furthermore in agreement with 3 isotopic and faunal reconstructions of the history of exchange transports through both the strait of sicily and the strait of gibraltar and 4 faunal and floral reflections of the presence or absence of a distinct deep chlorophyll maximum with its associated increases in export production indicating the presence or absence of a shallow pycnocline within the euphotic layer moreover the described scenario 5 is in no way conflicting with the reports of sapropels in the western mediterranean and 6 seems to be endorsed by occasionally intercalated intervals suggestive of somewhat improved oxygenation amidst anoxic benthic desert levels a situation that has been observed in a few quaternary and pliocene sapropels

the detailed tephrostratigraphy of a core from the south east black sea spanning the last 60 ka one visible volcanic ash layer and 21 non visible cryptotephra horizons have been identified in the m72 5 25 gc1 core from the south east black sea that spans the last 60 ka glass chemistry suggests that the tephras derive from italian hellenic and turkish sources the visible tephra layer is trachytic in composition and has been correlated to the 39 ka campanian ignimbrite super eruption from campi flegrei caldera italy two cryptotephra layers are associated with eruptions from acigol volcano turkey around the last glacial maximum another is linked to activity at erciyes dagi in the early holocene perikartini or karagullu and a cryptotephra layer near the top of the core correlates to the 3 6k cal a bp minoan marine z2 tephra from santorini thera greece this extends the known dispersal area for all these volcanic ash units many other calc alkaline rhyolite layers preserved in the core are likely to be from central anatolian sources but the lack of detailed proximal data for many of the volcanoes in the region prohibits further correlations the tephrostratigraphy and glass compositional data presented here allow the tephra layers to be used to correlate sedimentary archives across the region and help to extend the mediterranean tephrochronology framework towards the east

deposition models for chronological records abstract long term sedimentary sequences provide a wealth of useful information for research into the palaeo environment especially in relation to past climate change shorter records provide similar information in many archaeological contexts however if such records are to be used to provide precise timing of events and more critically the relative timing between different records methods are needed to provide accurate and precise age depth models for these sequences given the imprecision of individual calibrated radiocarbon determinations it is necessary to use the information we have about the deposition process to refine our chronologies and also to provide interpolation between dated levels in any sequence even with layer counted chronologies the uncertainties are sometimes hard to quantify this paper outlines a range of bayesian models for deposition which have been implemented in the computer programme oxcal these models can be used to combine information from the sediments themselves with radiocarbon or other direct dating information such models have the potential to integrate information between different records and provide a coherent chronology on which to base environmental or archaeological research