impact of the late glacial eruption of the laacher see volcano central rhineland germany abstract within a period of a few weeks toward the end of the allerod interstadial the major plinian eruption of the laacher see volcano produced some 20 km3 of eruptiva covering and preserving the late glacial landscape in the german central rhineland over an area of more than 1000 km2 correlation of terrestrial archives with the greenland ice core records and improved calibration of the radiocarbon timescale permit a precise accurate age determination of the laacher see event some 200 yr before the onset of the younger dryas cold episode carbonized trees and botanical macrofossils preserved by laacher see tephra permit detailed regional paleoenvironmental reconstruction and show that open woodland were typical for the cool and humid hemiboreal climatic conditions during the late allerod this woodland provided the habitat for a large variety of animal species documented at both paleontological and final paleolithic archeological sites preserved below laacher see deposits of special interest are numerous animal tracks intercalated in middle laacher see deposits at the south of the neuwied basin this knowledge may help to evaluate possible supraregional impacts of this volcanic event on northern hemispheric environment and climate during the late allerod

testing the laacher see hypothesis tephra as dental abrasive in a series of recent studies changes in material culture and settlement pattern in the late glacial of northern europe have been linked to the eruption of the laacher see volcano this eruption occurred c 13 000 years ago towards the end of the allerod chronozone it is argued that the tephra fall out from this eruption set in motion significant demographic fluctuations along the northern periphery of late glacial human settlement and that these led to a number of material culture transformations in particular the emergence of the regionally distinct techno complexes with large tanged points the bromme culture in southern scandinavia and the perstunian culture in northeastern europe and the temporary abandonment of central european regions are thought to relate to this eruption while numerous archaeological datasets are in accord with this laacher see hypothesis the forcing mechanism or mechanisms that brought about these archaeologically visible changes have remained largely unexplored a particular challenge is to explain how some of the culture historical effects of the laacher see eruption seem to change or become more pronounced with distance from the eruptive centre we here investigate one potential middle range link between the laacher see eruption and late glacial fauna and foragers tephra as dental abrasive we use instrumented nanoindentation to quantitatively investigate tephra from a number of sites covering the medial and distal fall out zones as well as the dental enamel of homo sapiens and key prey species of late glacial foragers our results show that the laacher see tephra contained particles roughly twice as hard as even the hardest portions of any of the teeth investigated we also suggest that fluoride induced weakening of dental enamel may have further aggravated tooth wear these mechanisms may have acted in concert to produce elevated levels of in particular animal mortality which in turn may have led to an abandonment of the affected landscapes

a laacher see eruption supplement to tephrabase investigating distal tephra fallout dynamics abstract tephrabase www tephrabase org is an online data repository and research tool for tephrochronological investigations in northern europe this paper presents and discusses an update to tephrabase that contains geographic and as far as available geochemical data on 452 data points for the widespread isochronous laacher see tephra this tephra is dated to c 12 920 calendar years bp and acts as an important chronostratigraphic marker for the lateglacial gi 1a late allerod chronozone in terrestrial and lacustrine palaeoenvironmental archives as well as in archaeological stratigraphies based on these data a revised map of the total tephra distribution is presented suggesting that the north eastern fallout lobe might contain a secondary fallout thickness maximum 230 340 km distant from the eruptive centre in addition new geochemical data from a series of distal tephra deposits spanning most of the north eastern fallout lobe are used to evaluate previous suggestions regarding the distribution of fallout from distinct eruption phases the aim of the study is that future tephrochronological investigations can use this database and the revised distribution map for effectively targeting sites for analysis

lateglacial calendar year chronology based on annually laminated sediments from lake meerfelder maar germany abstract annually laminated sediments from lake meerfelder maar mfm in the eifel germany provide an independent calendar year timescale for the last glacial interglacial transition changes in varve thickness and varve facies reflect significant environment variations during this period the general micro facies pattern confirms that diatomaceous organic varves are favoured during warm climatic phases while cold periods generate higher allochthonous sediment fluxes an exception is the significant increase in diatom blooms at the beginning of the younger dryas six lateglacial biozones have been defined by litt and stebich quaternary international 1999 the sediment record comprises two tephra layers as chronomarkers the laacher see tephra 12 880 varve years bp is a continent wide correlation horizon while the ulmener maar tephra provides regional chronological links the beginning of the lateglacial warming is dated at 14 450 varve years vyrs bp which is regarded as the minimum age three abrupt cold spells interrupted the lateglacial interstadial at 13 800 vyrs bp oldest dryas 13 540 vyrs bp older dryas and 12 680 vyrs bp younger dryas the oldest dryas 130 years and the older dryas 190 years were rather short while the younger dryas lasted much longer 1090 years the mfm chronology was compared with ice core timescales from gisp2 and grip there is a good agreement between these timescales with the grip model age ss09 providing the best match to the mfm chronology

evolution and environmental impacts of the eruption of laacher see volcano germany 12 900 a bp abstract laacher see volcano lsv 40 km south of bonn explosively erupted ca 6 3 km 3 of chemically strongly zoned phonolite magma probably during spring 12 900 years ago the resulting eruption column having reached at least 20 km in height the bulk of the laacher see tephra lst was deposited east of the volcano within the neuwied basin lst ashes form the most important stratigraphic marker in lateglacial deposits over much of central europe a minimum of 2 mt total s was calculated to have been released during the eruption by comparing pre and posteruptive volatile concentrations in glass inclusions and pumice matrix glasses because a separate s bearing vapor phase was probably present in the magma prior to eruption as indicated by the high melt h 2 o contents close to saturation level the actual amount of s released during the eruption could have significantly exceeded 2 mt the sulfuric acid aerosol layer resulting from the massive stratospheric s input probably resided in the stratosphere for years and most likely had a significant impact on climate and thus the environment increased precipitation in central europe and or impairment of the vegetation cover for several years is suggested by several proxies especially increased sediment supply into lakes proximal to the eruptive center major environmental impacts include an initial blast that felled trees up to 4 km away from vent fast deposition of huge tephra volumes led to the complete disruption of rhine river within the lower neuwied basin and the damming up of a lake ca 140 km 2 in areal extent sudden collapse of the temporary tephra dam caused a catastrophic flood wave downstream whose deposits are recognized as far north as bonn reworking of unconsolidated tephra deposits over several 100 km 2 was widespread and extensive generating abundant lahars and flood plain deposits a braided river system established in neuwied basin probably persisted up to several years recent reports for a second eruption of lsv are not confirmed

hierarchy of facies of pyroclastic flow deposits generated by laacher see type eruptions the upper quaternary pyroclastic flow deposits of laacher see volcano show compositional and structural facies variations on four different scales 1 eruptive units of pyroclastic flows composed of many flow units 2 depositional cycles of as many as five flow units flow units containing 3 regional intraflow unit facies and 4 local intraflow unit subfacies these facies can be explained by successively overlapping processes beginning in the magma column and ending with final deposition the pyroclastic flow deposits thus reflect major aspects of the eruptive history of laacher see volcano a drastic changes in eruptive mechanism due to increasing access of water to the magma chamber and b change in chemical composition and crystal and gas content as evacuation of a compositionally zoned magma column progressed the four scales of facies result from four successive sets of processes 1 differentiation in the magma column and external factors governing the mechanism of eruption 2 temporal variations of factors inducing eruption column collapse 3 physical conditions in the eruption column and the way in which its collapse proceeds and 4 interplay of flow inherent and morphology induced transport mechanics

phase equilibria of the lower laacher see tephra east eifel germany constraints on pre eruptive storage conditions of a phonolitic magma reservoir laacher see volcano erupted about 12 900 years ago resulting in a tephra blanket widely dispersed in central europe the eruption tapped a chemically and mineralogically strongly zoned phonolitic magma reservoir in order to better constrain the pre eruptive storage of that magma hydrothermal phase equilibria experiments have been performed on a powdered sample from the highly evolved phonolite of the lower laacher see tephra llst experiments were run at water pressures of 75 175 mpa and temperatures of 725 800 c stability fields of sanidine and amphibole the most common crystal phases in llst suggest that the magma last equilibrated at temperatures of 750 760 c and pressures of 115 145 mpa those conditions suggest the magma should have contained between 5 and 6 wt water which agrees well with water contents of 5 7 wt found in glass inclusions that agreement along with the observation that cl and s vary with the composition of the inclusions suggest that the laacher see magma was saturated at depth with a water rich fluid and thus was stored at pressures near those estimated from our experiments such pressures roughly correspond to depths of 5 6 km clinopyroxene and plagioclase did not occur in the experimental runs although present in the natural pumice sample it seems likely that these phases are not inherent to the llst they were formed in other parts of the chemically stratified column and later redistributed a recalculation of the magma density together with a new estimate of the temperature and pressure range suggests a steep density gradient and a thin withdrawal layer which is typical for volatile enriched magma bodies and confirms earlier models of convective fractionation in the laacher see magma reservoir

the impact of the laacher see tephra on terrestrial and aquatic ecosystems in the black forest southern germany late glacial lake sediments containing the laacher see tephra lst 11 000 yr bp have been analysed for pollen and diatoms at two sites hirschenmoor rotmeer in the montane belt of the black forest southern germany in order to detect the possible impact of this major volcanic eruption on terrestrial and aquatic biota the pollen assemblages at both sites show a minor increase in grasses and sedges following the tephra deposition whereas the pollen of aquatic macrophytes do not show any consistent pattern partial redundancy analysis and monte carlo permutation tests suggest however that the lst had no statistically significant effect either on the terrestrial or aquatic pollen assemblages at either site when the effects of time and climatic change are allowed for statistically the diatom assemblages at both sites changed after the deposition of the lst and diatom inferred ph estimates suggest a short but non significant excursion towards lower values multivariate analyses of the diatom data indicate a statistically significant impact of the deposition of the lst and associated changes in sediment lithology on the diatom assemblages when the effects of climatic change and time are allowed for statistically however owing to the interaction between tephra and lithology it is not possible to conclude if the diatom changes were caused by the deposition of the lst or by lithological changes

ash storms impacts of wind remobilised volcanic ash on rural communities and agriculture following the 1991 hudson eruption southern patagonia chile tephra fall from the august 1991 eruption of volcan hudson affected some 100 000 km 2 of patagonia and was almost immediately reworked by strong winds creating billowing clouds of remobilised ash or ash storms the immediate impacts on agriculture and rural communities were severe but were then greatly exacerbated by continuing ash storms this paper describes the findings of a 3 week study tour of the diverse environments of southern patagonia affected by ash storms with an emphasis on determining the impacts of repeated ash storms on agriculture and local practices that were developed in an attempt to mitigate these impacts ash storms produce similar effects to initial tephra eruptions prolonged for considerable periods these have included the burial of farmland under dune deposits abrasion of vegetation and contamination of feed supplies with fine ash these impacts can then cause problems for grazing animals such as starvation severe tooth abrasion gastrointestinal problems corneal abrasion and blindness and exhaustion if sheep fleeces become laden with ash in addition ash storms have led to exacerbated soil erosion human health impacts increased cleanup requirements sedimentation in irrigation canals and disruption of aviation and land transport ash deposits were naturally stabilised most rapidly in areas with high rainfall 1 500 mm year through compaction and enhanced vegetation growth stabilisation was slowest in windy semi arid regions destruction of vegetation and

pleistocene holocene transition in benelux in benelux belgium the netherlands and luxembourg considerable progress in late glacial and early postglacial archaeological and environmental research has been made during the last decade a substantial part of this paper discusses new evidence on the chronology of the industries which occupied the southern part of benelux dating the occupations from the sandy north is still problematic long after the glacial maximum during which the area remained uninhabited the south of benelux was visited by magdalenian hunter gatherers while hamburgian settlements were present in the north the significance of the continental creswellian is debated during the allerod interstadial federmesser groups occupied most of the area abandoning it with the onset of the younger dryas the presence of the ahrensburgian during that stadial may have been punctuated new elements were introduced and were maintained during the development of the preboreal early mesolithic which eventually colonised the entire region throughout this sequence changes in material culture and related subsistence activities are evident in view of the major problems concerning the quality of the chrono ecological data this paper can only suggest provisional explanations in terms of human reactions to changing environmental conditions

origin and emplacement of a pyroclastic flow and surge unit at laacher see germany abstract within the pyroclastic ejecta sequence of laacher see volcano west germany are many repeated phreatomagmatic depositional cycles a complete cycle begins with a thin low aspect ratio fines depleted breccia layer followed by a sequence with several coarse to fine grained cross bedded units in turn overlain by a massive pyroclastic flow layer each sequence is interpreted in terms of water magma interaction and effects upon the eruption column the breccia represents the triggering eruption with a high eruption column where fines were winnowed out and fallback from high altitudes produced a low aspect ratio layer the cross bedded sequence containing more fine grained ash resulting from an increase in amount of water represents a fluctuating eruption column of sufficient height to produce large antidunes within 700 meters of the rim the massive pyroclastic flow layer which contains more fine grained ash than the underlying layers represents the culmination of the eruption where an increase in amount of water interacting with the magma resulted in a dense and very low eruption column producing a dense laminar moving pyroclastic flow

icelandic volcanic ash from the late glacial open air archaeological site of ahrenshoft la 58 d north germany abstract cryptotephra of icelandic origin from the open air archaeological site of ahrenshoft la 58 d kr nordfriesland schleswig holstein northern germany overlies a late glacial havelte lithic assemblage hitherto dated by 14 c and biostratigraphy to the earliest part of the late glacial interstadial gi 1e to gi 1c 3 peaks in ash shards are observed in two profiles major and minor element geochemistry indicates volcanic ash originating in the katla system precise correlation to previously described tephra is uncertain due to overlapping chemical characteristics the ahrenshoft 14 c determinations litho and bio stratigraphy encompass a broad age span for the cryptotephra bearing sediments from the end of the allerod to the preboreal the most plausible volcanic eruption correlates are the vedde ash younger dryas already known from the european mainland tephra af555 late younger dryas and the suduroy tephra preboreal boreal hitherto recorded only in the north atlantic region these three ash horizons have been dated to respectively 12 171 57 yr b2k in the ngrip ice core c 11 500 cal bp in scotland and c 8000 cal bp by radiocarbon from the faroe isles ongoing research on deposits from the type sites for the tephra layers may in the future differentiate these markers leading to better discrimination of the chemistries and a resolution of this question

late glacial and holocene history of former salziger see central germany and its climatic and environmental implications an 8 40 m long sediment sequence from the salziger see basin central germany was investigated by a multi disciplinary approach including chronological sedimentological geo and biogeochemical methods radiocarbon dating conducted on ten samples of aquatic and terrestrial fossil remains and the occurrence of the laacher see tephra lst reveal that the sediment sequence comprises the late glacial and holocene lake history since ca 13 800 cal year bp this onset of lacustrine sedimentation is almost 7 000 years earlier as assumed so far the geo and biogeochemical data indicate distinct variations throughout the late glacial which can be correlated with cold and warm periods such as the oldest dryas the bolling the allerod and the younger dryas during most of the holocene minor variations in the geo and biogeochemical data and a high carbonate content due to the formation and precipitation of autochthonous carbonate in the lake indicate relatively stable lacustrine conditions a slight change in the sedimentary conditions between 6 700 and 4 000 cal year bp with lower deposition of carbonate and fine material can be traced back to enhanced subrosion in the basin increased deposition of coarser sediments and a high accumulation of heavy metals document intensive human activity in the region during the past ca 1 000 years

the relationship between viscosity and temperature in the system anorthite diopside abstract the viscosity temperature relationships of supercooled melts of six intermediate compositions of the system anorthite diopside have been determined in the viscosity range 1013 108 dpa s with a micro penetration viscometer it is shown that the isothermal viscosities of the intermediate compositions may be calculated from the pertinent data of the end members anorthite and diopside in fair agreement with the experimental data using the viscosity model based on the theory of configurational entropy together with a slightly modified version of the two lattice entropy of mixing model

volatile composition of the phonolitic laacher see magma 12 900 yr bp implications for syn eruptive degassing of s f cl and h 2 o a volatile rich and chemically zoned phonolitic magma reservoir was tapped successively during the eruption of laacher see volcano ca 12 900 years bp and produced a tephra sequence consisting of phenocryst poor highly evolved phonolite at the base and phenocryst rich more mafic phonolite at the top the stratospheric volatile loading was estimated by comparing pre and post eruptive s f cl and h2o contents of undegassed glass inclusions and partially degassed matrix glasses glass inclusions 150 1490 ppm s and host matrix glasses 150 820 ppm s both document a strong s decrease during progressive magmatic differentiation which is interpreted to be partially caused by crystallization of hauyne the s6 stotal ratio of the pre eruptive melt increased with differentiation from 8 to 71 as indicated by s k wavelength shift measurements in glass inclusions sulfate rich highly evolved phonolitic magma was erupted during plinian and sulfide rich more mafic phonolitic magma during late phreatomagmatic phases f and cl became enriched during late stages of differentiation glass inclusions 690 4060 ppm f 1770 4400 ppm cl matrix glasses 680 3660 ppm f 2130 4330 ppm cl the most differentiated melts maximum 13 wt na2o occur only as matrix glass and are extremely f enriched 5080 8780 ppm but cl depleted 460 2820 ppm suggesting that f was retained in the melt whereas some cl was lost during pre and or syn eruptive degassing the h2o contents of glass inclusions increase irregularly with differentiation 2 5 5 7 wt matrix glasses are h2o depleted 0 2 2 8 wt compared to most glass inclusions showing that most h2o was released to the atmosphere by explosive degassing a mass balance calculation yields a syn eruptive volatile release of 1 9 tg stotal 6 6 tg cl and 403 tg h2o from the melt this is a minimum estimate since s and cl could have accumulated in a separate fluid phase as indicated by fluid inclusions in hauyne and pre eruption h2o contents close to saturation level at the likely pressure temperature conditions in the laacher see magma reservoir we estimate that at least ca 20 tg so2 were injected into the stratosphere causing a significant negative climate forcing as reflected by several paleoclimate proxies and as shown by recent modeling

tephra studies and the reconstruction of middle to upper paleolithic cultural trajectories abstract this study describes an approach which combines tephra records with archaeological and contextual data in order to propose best fit scenarios for past cultural changes and population events with this goal in mind we critically examine the environmental archaeological anthropological and chronometric records of the middle to upper paleolithic mup transition 45 35 ka in europe and identify a number of shortcomings that make it difficult to correlate and interpret current evidence with respect to historical processes the utility and limitations of tephra records are highlighted and an heuristic strategy designed to merge evidence from tephra and other proxies is described such a strategy is used to explore the stratigraphic and chronological relationship between the campanian ignimbrite ci eruption and the cultural changes that occurred during the mup transition in southern europe uncertainties pertaining to the timing of this volcanic event are discussed before summarizing the stratigraphic and cultural sequences of the eleven archaeological sites haua fteah kozarnica franchthi cave klissoura golema pesht cavallo serino castelcivita tabula traiana temnata kostenki 14 where the ci tephra has been reliably identified along with three sites uluzzo uluzzo c bernardini where such an identification remains tentative we conclude that if one discards as inconclusive the recent attribution of the uluzzian to modern humans the best fit historical scenario that stems from a critical reading of the evidence identifies the uluzzian as the result of in situ cultural evolution of late mousterian populations in this region of southern europe such evolution which entails the independent development of cultural innovations typically found in subsequent cultures of the upper paleolithic would have been truncated before the ci event by the arrival of modern or neanderthal modern hybrid populations bearing the proto aurignacian material culture

changes in mid and far field human landscape use following the laacher see eruption c 13 000 bp abstract around 13 000 years ago the laacher see volcano east eifel volcanic field rhenish shield erupted cataclysmically the thick tephra blanket in the eruption s near field covered and thereby preserved a large number of archaeological sites ranging from very small to some of the largest and richest sites known from the late glacial in this proximal region there is a striking contrast in the number of sites prior to the eruption and the almost complete lack of sites dating to the period after the event i e to greenland interstadial 1a the preservative function of the tephra cover itself may explain this near field pattern but it is shown here that similar stratigraphic observations can also be made in the laacher see eruption s mid field towards the west and in particular to the north east the aim of this paper is to review the stratigraphic relations of known archaeological sites outside the near field of the laacher see event with a particular focus on the german federal state of hesse and adjacent areas of lower saxony and the thuringian basin here a number of archaeological sites are known where strata of laacher see tephra cap human occupation most often these sites are not reoccupied until much later in prehistory suggesting that the eruption may have led either to a complete or a near complete abandonment of the affected regions or at the very least to a major reorganisation of landscape use

the 12 900 years bp laacher see eruption estimation of volatile yields and simulation of their fate in the plume we estimated the volatile emissions of the 12 900 years bp eruption of laacher see volcano germany using a modified petrological method glass inclusions in phenocrysts and matrix glasses sampled over the laacher see tephra profile were analysed by synchrotron x ray fluorescence microprobe and electron microprobe to obtain the emitted masses of halogens sulphur and water these data were used to initialize the numerical plume model atham in order to investigate the fate of volcanic gases in the plume and to estimate volatile masses injected into the stratosphere the scavenging efficiency of each volatile component depends on its interactions with both liquid water and ice we found a scavenging efficiency of c 5 for the sulphur species and of only c 30 for hydrogen halides despite their high water solubility our simulations showed that the greatest fraction of hydrometeors freeze to ice due to the fast plume rise and great height of the eruption column for the dry atmospheric conditions of the laacher see eruption the amount of liquid water was not sufficient to completely scavenge hcl and hbr so that a large proportion could reach the stratosphere

volcanism and the greenland ice cores the tephra record abstract in recent years increased awareness of the considerable potential offered by tephrochronology in palaeoclimatic studies has fuelled a renewed interest in the tephra record preserved within the greenland ice cores this renewal has occurred in tandem with the development of continuous flow analysis techniques which provide high resolution volcanic aerosol records these chemical records are of considerable value for identifying tephra horizons composed of glass shards and also provide the basis for a new high precision ice core timescale thus allowing ages to be assigned to volcanic events tephra horizons of glass shards in the ice cores play a critical role for 1 testing and building chronological frameworks for the ice cores and other sequences 2 synchronising disparate palaeoclimatic sequences and testing phase relationships 3 atmospheric pathway reconstruction and 4 verifying the source of volcanic aerosol peaks here we review the results of over 25 years of research into tephra horizons in the grip gisp2 and ngrip cores we provide high precision ages for horizons based on recently developed timescales and draw together geochemical characterisations of the products of 45 volcanic events deposited on the greenland ice sheet and identified in the cores there is a clear disparity between the number of volcanic aerosol peaks and the number of tephra horizons of glass shards identified thus far however this synthesis highlights the critical role of the greenland ice cores firstly in the reconstruction of the history of icelandic volcanic eruptions and secondly the considerable value of some tephra horizons in facilitating the correlation of these key climatic archives to north atlantic marine sequences other noteworthy issues include the potential of these cores to preserve tephra horizons from more distal volcanic sources such as north america to resolve the debate surrounding the thera eruption and the observation that some tephra horizons are preserved within the ice without coeval volcanic aerosol signals

structure of the european upper mantle revealed by adjoint tomography the structure of the european crust and upper mantle is precisely known only in limited regions a new tomographic model for the entire european upper mantle identifies northeastward subduction of the adria plate beneath the dinarides mountains volcanism related to the upwelling eifel hotspot and mantle delamination beneath scandinavia

40ar 39ar laser dating of single grains ages of quaternary tephra from the east eifel volcanic field frg four late pleistocene tephra deposits from the east eifel volcanic field have been dated by 40ar 39ar single grain laser fusion of k feldspar and phlogopite crystals this is a high speed and high precision technique which because it is grain specific can directly detect the presence of older contaminating material our results indicate that the huttenberg tephra from wehr volcano erupted 213 4 ka bp and that the rieden volcanic complex erupted at least over the period 410 to 470 ka bp essential rieden phonolite lapilli contain abundant sanidine with apparent ages older than the eruption age

varve chronology and palynology of the lateglacial in northwest germany from lacustrine sediments of hamelsee in lower saxony abstract the hamelsee is a dolina from a collapse over permian salt that occurred at the end of the pleniglacial it is more than 21 m deep and contains 18 m of lacustrine sediments the lateglacial sediments in the central part of the lake consist of 2 7 m from 15 to 17 7 m of sapropelic and silty muds which are mostly laminated and partly bioturbated minor slumps occur mainly during colder phases the subdivision of the lateglacial is based on pollen zones multidisciplinary studies of the microfacies from thin sections geochemistry pollen analysis and rotifer analysis allow environmental and palaeoclimatological interpretations to be made the biozones of the lateglacial and their boundaries are marked by rapid climatic changes though covering comparatively short periods of time they are not monotonous but characterized by minor internal climatic fluctuations the sediments of the meiendorf and oldest dryas are not laminated the allerod sediment is seasonally varved without interruption and encompasses 625 yr the eruption of the laacher see volcano 12 900 cal bp had an impact on the climate during the following 10 yr the transition from the allerod to the younger dryas took some 50 yr and it occurred 200 yr after the eruption of the laacher see volcano the abrupt change at the end of the lateglacial 11 560 cal bp occurred within less than 10 yr however many proxies reacted with a time lapse of 15 to 30 yr

dating the trollesgave site and the bromme culture chronological fix points for the lateglacial settlement of southern scandinavia abstract the bromme culture belongs to the lateglacial the period when people settled in the recently deglaciated southern scandinavia until now there have been only a few imprecise fix points relating to the chronological position of this archaeological culture this situation can now be improved with the aid of research results from a bromme culture settlement at trollesgave in se denmark using pollen and plant macrofossil data lateglacial lacustrine deposits containing waste material from the settlement can be assigned to the end of the climatically mild allerod period a series of 14 c dates establishes the age of the settlement as c 10 826 49 14 c years bp 12 871 12 590 cal yr bp by correlation with climate data from the greenland ice cores the occupation can be assigned to the early part of the cold climatic zone gs 1 thus demonstrating that the global ice core climate zones are not absolutely synchronous with the regional division into biozones

chronostratigraphic context of the middle to upper palaeolithic transition recent data from belgium abstract the chronological and palaeoenvironmental context for the industries identified in europe during the middle to upper palaeolithic transition mupt is not accurately known this situation is mainly due to insufficient knowledge of the context of the archaeological data much of which comes from old excavations any major progress in the understanding of the mupt can only be achieved with the study of long sedimentary sequences providing a semi continuous record and situating archaeological remains in a reliable palaeoenvironmental and chronological framework strict attention must also be paid to stratigraphic control and site formation processes interdisciplinary studies undertaken over the last ten years in belgium contribute to research on the mupt belgium plays an important role due to its specific geological context that includes many caves a well developed loess cover which acts as a reference sequence for the upper pleistocene and the presence of tephras this enables detailed reconstruction of climatic change and more accurate chronological control in cave sequences initial results from new fieldwork on long sequences are presented here walou and scladina caves as well as the open air site of maisieres canal combined with results of recent analyses on old material mainly from the spy and trou de l abime collections they enable establishment of a reliable and more accurate chronostratigraphic framework for the archaeological assemblages and provide new data on the humans responsible for them thus around 45 000 bp a mousterian industry was made by neandertals in trou de l abime around 40 000 38 000 bp belgium was still occupied by neandertals associated with a typical middle palaeolithic as shown in walou the spy neandertals have recently been directly dated by 14c to 36 000 bp but the techniques of the early excavations prevent clear identification of the associated industry still the 14c results are more coherent with the lincombian ranisian jerzmanowician lrj chronology than the mousterian both of which are identified at spy the earliest convincing age for the belgian aurignacian is about 32 000 33 000 bp maisieres canal and spy

geomagnetic field intensity in early jurassic investigation of the newark supergroup eastern north america abstract a collection of 220 samples from early jurassic newark supergroup volcanic units watchung talcott holyoke hampden and deerfield basalts and intrusive units manitook and palisades sills was studied with the aim of testing the previously suggested occurrence of a low average dipole moment of the earth s magnetic field some 200 ma ago after viscosity tests alternating field demagnetization of all samples and thermal variation studies of saturation magnetization of 74 selected samples we find that only 8 of the entire collection was a priori suitable for paleointensity experiments using the original thellier and thellier method we have obtained 17 reliable paleointensity values of average quality from the palisades sill and the holyoke basalt although these two units recorded substantially different field directions they provide similar estimates of the virtual dipole moment 9 4 1 2 and 11 3 2 2 10 22 a m 2 respectively these values are within the range of secular variation of the recent geomagnetic field

north european last glacial interglacial transition lgit 15 9 ka tephrochronology extended limits and new events high precision correlation of palaeoclimatic and palaeoenvironmental records is crucial for testing hypotheses of synchronous change although radiocarbon is the traditional method for dating late quaternary sedimentary sequences particularly during the last glacial interglacial transition lgit 15 9 ka there are inherent problems with the method particularly during periods of climate change which are often accompanied by major perturbations in atmospheric radiocarbon content an alternative method is the use of tephras that act as time parallel marker horizons within europe numerous volcanic centres are known to have erupted during the lgit providing considerable potential for high precision correlation independent of past radiocarbon fluctuations here we report the first identification of the vedde ash and askja tephra in ireland significantly extending the known provenance of these events we have also identified two new horizons the roddans port tephras a and b and tentatively recognise an additional horizon from vallensgard mose denmark that provide crucial additional chronological control for the lgit two phases of the laacher see tephra lst are reported the lower laacher see tephra llst and probably the c2 phase of the middle laacher see tephra mlst c2 indicating a more northeasterly distribution of this fan than reported previously copyright 2006 john wiley sons ltd

a tephrochronology for the lateglacial palynological record of the endinger bruch vorpommern north east germany the tephrostratigraphy of lake sediments in the endinger bruch provides the first robust age model for the lateglacial palynological records of vorpommern north east germany cryptotephra investigations revealed six tephra layers within sediments spanning from open vegetation phase i bolling 15 ka to the early holocene betula pinus forest phase pre boreal 10 5 ka four of these layers have been correlated with previously described tephra layers found in sites across europe the laacher see tephra eifel volcanic field is present in very high concentrations within sediments of the lateglacial betula pinus forest phase allerod the vedde ash iceland lies midway through open vegetation phase iii younger dryas the hasseldalen and the askja tephras iceland lie in the early holocene betula pinus forest phase preboreal these tephra layers have independently derived age estimates which have been imported into the endinger bruch record furthermore the layers facilitate direct correlation of the regional vegetation record with other palaeoenvironmental archives which contain one or more of the same tephra layers from greenland to southern europe in doing this localized variations are confirmed in some aspects of the pollen stratigraphy however transitions between the main vegetation phases appear to occur synchronously within centennial errors with the equivalent environmental transitions observed in sites across the european continent copyright 2011 john wiley sons ltd

the eruptive center of the late quaternary laacher see tephra about 5 km3 of phonolite magma were erupted 11 000 years ago in the laacher see area in plinian and vulcanian eruptions the eruptive vents for all tephra in dispute for over 200 years must have been located entirely within the laacher see basin because 1 all deposits are thickest in the tuffring surrounding the basin with one exception pyroclastic flow deposits are thickest 2 to 6 km away from the rim of the basin having ponded in radial valleys three plinian fallout layers show minor secondary thickness maxima 12 to 16 km east of laacher see 2 axes of all depositional fans and single tephra sheets converge in the laacher see basin 3 diameters of both lithic and pumice clasts reach their maxima in outcrops close to laacher see volcano 4 directions of asymmetric ballistic impact sags indicate the laacher see basin as source area 5 the dimension of laacher see crater roughly corresponds to the erupted volume of phonolitic tephra 5 3 km3 magma dre and lithic clasts 0 7 km3 6 xenolith types are consistent with an eruptive center within the laacher see basin 7 the systematic chemical and mineralogical zonation of the tephra deposits from highly differentiated aphyric phonolite at the base to highly phyric mafic phonolite at the top strongly suggests eruption from a single compositionally zoned magma column 8 several lines of evidence indicate migration of the main eruptive focus from the south to the north during the later part of the eruption both vents however being confined within the laacher see basin

tracing the laacher see tephra in the varved sediment record of the trzechowskie palaeolake in central northern poland abstract tephrochronological studies of partly varved sediments of trzechowskie palaeolake in central northern poland led to the finding of the late allerod laacher see tephra lst from the eifel volcanic field for the first time in a very distal site ca 840 km ene from its volcanic source the detection of glass shards of the lst involved a comprehensive combination of techniques i e biostratigraphical constrains high resolution xrf core scanning and areal xrf mapping of impregnated sediment slabs as well as detailed visual inspection of sediments the major element chemistry of volcanic glass confirmed the laacher see tephra composition in trzechowskie palaeolake sediments suggesting a deposition from the middle laacher see tephra mlst c or upper laacher see tephra ulst dispersal fans the finding of the lst in this palaeolake enables direct synchronisation with other high resolution archives in north central europe i e lake meerfelder maar rehwiese palaeolake to investigate regional variations of environmental responses at the onset of the younger dryas along a west east transect through north central europe

tephrostratigraphy of a lateglacial lake sediment sequence at wegliny southwest poland abstract this paper presents the first late quaternary locality in the present day territories of poland where multiple cryptotephra layers have been identified located near wegliny in southwest poland study of the lateglacial gyttja deposits reveals the presence of at least four non visible tephra horizons electron microprobe and laser ablation icpms analysis of glass shards suggests products from at least two icelandic volcanic centres katla and snaesfellsness of particular importance is the discovery of two eruptions believed to originate from the east eifel volcanic field within the allerod chronozone one correlates with the well documented laacher see tephra lst but the second horizon herein designated t642 t655 would appear to represent an earlier precursor eruption the chemical composition of the lst and the precursor tephra both appear to match to the upper laacher see tephra ulst phase which previously was thought to have dispersed not to the northeast but in a southerly direction towards the alpine foreland this indicates the eruption dynamics of the laacher see are more complex than hitherto recognised

quantification of gas fluxes from the subcontinental mantle the example of laacher see a maar lake in germany abstract vertical and horizontal distributions of helium and neon isotopes were measured in the water of laacher see a maar lake in the east eifel volcanic field in germany neon is in approximate atmospheric equilibrium throughout the lake but the concentrations of both helium isotopes increase with depth and reach values of up to 10 4 he and 50 3 he times the atmospheric equilibrium concentration the isotopic ratio of the helium excess r ex 3 he ex 4 he ex is 7 42 0 03 10 6 i e r ex r a 5 36 0 02 where r a 1 384 10 6 is the isotopic ratio in air this indicates the presence of mantle derived helium laacher see is thermally stratified during the summer it acts as an almost perfect trap for injected gases the helium concentration in the hypolimnion deep water approximately doubled from may to september 1991 yielding a mean 4 he flux of 10 2 10 12 atoms m 2 s 1 this value is 30 times smaller than in lake nyos cameroon but 20 times larger than in crater lake usa release of bubbles of nearly pure co 2 99 observable in shallow waters at the eastern shore as well as detected by divers in about 30 m depth was identified as an important source of the helium excess in the lake if carefully sampled by divers to avoid air contamination the bubbles exhibit mantle influenced isotopic signatures not only for helium but also for neon and argon 20 ne 22 ne 9 92 0 03 40 ar 36 ar 391 4 based on the elemental ratios of carbon neon and argon to 3 he the fluxes of volatiles from the mantle into laacher see are determined as 7 4 10 7 atoms m 2 s 1 for 3 he 13 10 7 atoms m 2 s 1 for 20 ne 26 10 7 atoms m 2 s 1 for 361 ar and 6 4 10 17 molecules m 2 s 1 for co 2 non atmospheric neon was also found in the well wallenborn in the west eifel volcanic field with a 20 ne 22 ne ratio as high as 11 21 0 06

characterisation of andosols from laacher see tephra by wet chemical and spectroscopic techniques ftir 27al 29si nmr abstract at 12 900 a bp the eruption of the laacher see volcano generated a new parent material for holocene soil formation in parts of western germany weathering of these ashes commonly includes the formation of poorly crystalline minerals such as allophane imogolite and ferrihydrite detection of these minerals in soil is difficult yet an important task because they may govern soil functions and processes e g stabilisation of organic matter and nutrient availability therefore we characterised three forested andosols by a combination of wet chemical and spectroscopic techniques including infrared and 27 al 29 si nuclear magnetic resonance nmr spectroscopy together with x ray diffractometry deconvoluting the 29 si nmr spectra revealed that 1 6 to 10 4 of total si was present as allophanic compounds which coincided with the amounts of oxalate extractable si since extraction methods are not completely selective we observed a slight overestimation of allophanic si estimated from oxalate extraction although the sites under study are located close to each other in similar relief positions and with similar vegetation the combination of our results revealed varying amounts of loess in the parent materials and varying weathering intensity high weathering intensities correlate with the amounts of allophane

volcanoes and human history abstract the study of volcanic hazards leads inevitably to questions of how past cultures have lived in volcanically active regions of the world here we summarize linkages between volcanological archaeological and anthropological studies of historic and prehistoric volcanic eruptions with the goal of evaluating the impact of past eruptions on human populations to better prepare for future events we use examples from papers collected in this volume to illustrate ways in which volcanological studies aid archaeological investigations by providing basic stratigraphic markers and information about the nature and timing of specific volcanic events we then turn to archaeological perspectives which provide physical evidence of the direct impacts of volcanic eruptions such as site abandonment and human migration as well as indirect impacts on local cultures as reflected in human artifacts finally we review anthropological studies of societal responses to past and recent volcanic eruptions we pay particular attention to both the psychological impact of catastrophic events and records of these impacts encoded within oral traditions taken together these studies record drastic short term eruption impacts but adaptation to volcanic activity over the longer term largely through strategies of adaptive land use

environmental impact of the laacher see eruption at a large distance from the volcano integrated palaeoecological studies from vorpommern ne germany abstract in order to investigate the environmental impacts of the laacher see eruption 12 900 calendar years b p and the deposition of the laacher see tephra at a large distance from the volcano fine resolution micromorphological diatomological and palynological investigations were carried out on closely spaced areas in the reinberg basin vorpommern ne germany the lower part of the lst originates from atmospheric input whereas the upper part was washed in from the surrounding basin slopes diatom populations expanded as a consequence of the input of silica while simultaneously dissolution of dead diatoms decreased the tephra provided a favourable habitat for many epilithic and epipelic diatom taxa the diatoms show a slight acidification and an increase in specific conductivity of the water whereas no eutrophication is indicated these effects disappeared after lake sediments covered the tephra the pollen diagrams from the reinberg basin as well as many other pollen diagrams from ne germany indicate that the vegetation reacted to rising temperatures after the cooler gerzensee fluctuation to a short lived water level rise connected with higher precipitation after the volcanic eruption and to minor openings in the forest vegetation due to increased fire probably connected with severe thunderstorms

high resolution late glacial chronology for the gerzensee lake record switzerland δ18o correlation between a gerzensee stack and ngrip oxygen isotope variations were analyzed on bulk samples of shallow water lake marl from gerzensee switzerland in order to evaluate major and minor climatic oscillations during the late glacial to highlight the overall signature of the gerzensee 18o record 18o records of four parallel sediment cores were first correlated by synchronizing major isotope shifts and pollen abundances then the records were stacked with a weighting depending on the differing sampling resolution to develop a precise chronology the 18o stack was then correlated with the ngrip 18o record applying a monte carlo simulation relying on the assumption that the shifts in 18o were climate driven and synchronous in both archives the established chronology on the gicc05 time scale is the basis for 1 comparing the 18o changes recorded in gerzensee with observed climatic and environmental fluctuations over the whole north atlantic region and 2 comparing sedimentological and biological changes during the rapid warming with smaller climatic variations during the bolling allerod period the 18o record of gerzensee is characterized by two major isotope shifts at the onset and at the termination of the bolling allerod warm period as well as four intervening negative shifts labeled gi 1e2 d c2 and b which show a shift of one third to one fourth of the major 18o shifts at the beginning and end of the bolling allerod despite some inconsistency in terminology these oscillations can be observed in various climatic proxies over wide regions in the north atlantic region especially in reconstructed colder temperatures and they seem to be caused by hemispheric climatic variations

delayed hydrological response to greenland cooling at the onset of the younger dryas in western europe during the younger dryas cold event about 12 800 years ago environmental change in western europe seems to occur 170 years after cooling over greenland lake sediment analyses confirm this delay and suggest european hydrological and vegetation change occurred only after the build up of sea ice in the north atlantic pushed the westerly wind system south

laacher see tephra a widespread isochronous late quaternary tephra layer in central and northern europe a late quaternary tephra layer widespread in central and northern europe resulted from explosive plinian and phreatomagmatic eruptions of the laacher see volcano 11 000 yr b p the tephra is distinguished from other late quaternary andesitic rhyolitic airfall tuff layers in northern europe and from basaltic or trachytic tuff deposits in southern europe by its phonolitic composition and abundance of sanidine plagioclase clinopyroxene amphibole and sphene the proximal tephia sequence at laacher see is divided into three main deposits the predominantly plinian deposits of lower and middle laacher see tephra llst and mlst and phreatomagmatic deposits of the upper laacher see tephra ulst the mlst member is further subdivided into beds a b and c1 c2 and c3 the chemical composition of the magma is highly differentiated phonolite in the llst to mlst b sections but mafic phonolite in the mlst c1 to ulst sections all deposits are considered to be isochronous the frequency maximum of 16 radiocarbon datings indicating an eruption about 11 000 50 yr b p distal ash was deposited in three main fans directed to the northeast lst traced up to 1 100 km distance south lst traced up to 600 km and southwest lst traced up to 100 km tephrostratigraphic correlation of the distal ash deposits is based on a the major element composition of glass shards b lithology and c heavy mineral analyses the northeastern fan consists of deposits from llst mlst b and mlst c1 eruptive phases the southern fan comprises mlst a mlst c2 and ulst deposits and the southwestern fan consists exclusively of ash from the ulst eruptive phase northeastern transport of ash during eruptive phases with high plinian eruption columns but southern and southwestern transport of ash along phases of relatively low eruption columns are interpreted in terms of prevailing southwesterly paleowinds at high altitudes tropopause level but northerly winds dominating in the lower atmosphere the laacher see eruption columns were emplaced into an atmosphere vertically zoned with respect to paleowind directions which also explains the near vent shifting of llst mlst b and mlst c1 iso pach axes from east southeast to northeast within the first 20 km of transport

ams radiocarbon dating of annually laminated sediments from lake holzmaar germany ams radiocarbon ages have been determined on terrestrial macrofossils selected from the annually laminated sediments of lake holzmaar germany the radiocarbon chronology of this lake covers the last 12 6 ka comparison of the radiocarbon dated varve chronology with tree ring data shows that an additional 878 years have to be added to the varve chronology the corrected c 14 varve chronology of holzmaar reaches back to ca 13 8 ka cal bp and compares favourably with the results from soppensee switzerland hajdas et al 1993 the corrected ages for the onset and the end of the younger dryas biozone are 11 940 cal bp and 11 490 cal bp respectively the ash layer of the laacher see volcanic eruption is dated at 12 201 224 cal bp and the ulmener tephra layer is dated at 10 904 cal bp

aspects of armageddon an exploration of the role of volcanic eruptions in human history and civilization volcanic eruptions are frequently invoked as the mechanism responsible for changes observed in the archaeological and environmental record this paper argues that the evidence for this assumption is slight and that while there are examples of this they are rare several case studies are discussed which illustrate the complex nature of the relationship between human cultures and volcanic eruptions and it is suggested that volcanic activity frequently acts as a stimulus rather than a brake to cultural development

synchronisation of palaeoenvironmental events in the north atlantic region during the last termination a revised protocol recommended by the intimate group abstract the north atlantic intimate group of the inqua palaeoclimate commission has previously recommended an event stratigraphy approach for the synchronisation of records of the last termination using the greenland grip isotopic record as the regional stratotype and intcal98 for the calibration of radiocarbon dates lowe j j hoek w intimate group 2001 inter regional correlation of palaeoclimatic records for the last glacial interglacial transition a protocol for improved precision recommended by the intimate project group quaternary science reviews 20 1175 1187 here we present a revised protocol for time stratigraphic correlation in the north atlantic region over a more extended time period 30 8 ka this employs the new ngrip isotopic record and associated greenland ice core chronology 2005 gicc05 as the regional stratotype intcal04 for the calibration of radiocarbon dates bayesian based statistical procedures for the construction of age models and tephrochronology to validate correlations between regional site records

testing the laacher see hypothesis a health hazard perspective it has recently been suggested that the laacher see volcanic eruption which occurred around 13 000 years ago initiated significant demographic fluctuations along the northern periphery of late glacial human settlement and that these led to a number of material culture transformations the origins of the southern scandinavian bromme culture and the northeastern european perstunian culture as well as the temporary abandonment of central european regions have been linked to this eruption however it remains unclear precisely which aspects of the eruption stimulated late glacial foragers to abandon their traditional ways of life paradoxically the culture historical impact of the eruption appears greater further away from the eruptive centre here we investigate one potential middle range link between the laacher see eruption and late glacial fauna and foragers tephra as a health hazard we use laser diffraction particle size analysis to quantitatively investigate tephra from one site with a secure late glacial archaeological deposit in addition we use values previously reported in the literature and a predictive model to calculate the hazard potential along a transect of two of the three major laacher see tephra fans our results show that the laacher see tephra may have posed a potential health hazard and that its hazard potential may have increased with distance from the vent to our knowledge this is the only study that attempts to quantify the changing grain size composition of tephra fall out longitudinally in this way at least with regard to a prehistoric eruption we close by discussing more speculatively other possible health pertinent effects of the laacher see eruption and suggest ways in which future work can further evaluate the impact of this eruption on late glacial populations

cryptotephra as a dating and correlation tool in archaeology a new development in archaeological chronology involves the use of far travelled volcanic ash which may form discrete but invisible layers within a site s stratigraphy known as cryptotephra these horizons can provide isochrons for the precise correlation of archaeological records at single moments in time removing or at least significantly reducing temporal uncertainty within inter site comparisons when a tephra can be dated elsewhere its age can be imported between records providing an independent check on other dating methods in use and valuable age estimates for difficult to date sequences the use of cryptotephra layers to date and correlate palaeoenvironmental archives is well established and there exists a wealth of tephra compositional data and regional tephrostratigraphic frameworks from which archaeological cryptotephra studies can benefit greatly existing approaches to finding and analysing cryptotephra are easily adapted to archaeological sequences so long as the often complex nature of archaeological stratigraphies and sediment taphonomy are borne in mind

local impact of palaeolithic man on the environment during the end of the last glacial in the netherlands abstract comparison of palynological data from lake deposits and soils from locations along a transect approaching the remains of a palaeolithic settlement in the younger dryas stadial shows four cycles in the vegetation from open pine forest to open ground vegetation and back to open pine forest this outcome is discussed in terms of the impact of man on the vegetation in the later part of the weichselian lateglacial

volcanic ash reveals time transgressive abrupt climate change during the younger dryas knowledge of regional variations in response to abrupt climatic transitions is essential to understanding the climate system and anticipating future changes global climate models typically assume that major climatic changes occur synchronously over continental to hemispheric distances the last major reorganization of the ocean atmosphere system in the north atlantic realm took place during the younger dryas yd an 1100 yr cold period at the end of the last glaciation within this region several terrestrial records of the yd show at least two phases an initial cold phase followed by a second phase of climatic amelioration related to a resumption of north atlantic overturning we show that the onset of climatic amelioration during the yd cold period was locally abrupt but time transgressive across europe atmospheric proxy signals record the resumption of thermohaline circulation midway through the younger dryas occurring 100 yr before deposition of ash from the icelandic vedde eruption in a german varve lake record and 20 yr after the same isochron in western norway 1350 km farther north synchronization of two high resolution continental records using the vedde ash layer 12 140 40 varve yr b p allows us to trace the shifting of the polar front as a major control of regional climate amelioration during the yd in the north atlantic realm it is critical that future climate models are able to resolve such small spatial and chronological differences in order to properly encapsulate complex regional responses to global climate change

the lateral facies of ignimbrites at laacher see volcano valley fill ignimbrites of the middle laacher see tephra mlst in the proximal depositional fan south of laacher see volcano are laterally continuous with fine grained overbank facies deposits 0 5 1 5 m thick covering higher elevations and interfluves between the paleovalleys the overbank deposits consist of up to 12 ash layers each 4 10 cm thick which show internal structures typical of ash flow transport such as poor sorting reverse size grading of pumice local normal grading of coarse ash sized lithics above a fine grained basal layer cross stratification behind obstacles and erosional unconformities thickness median grain size and number of individual layers decrease systematically with distance from the vent overbank ash layers thicken at the valley slopes and form discrete valley fill ignimbrite flow units in the paleochannels with median grain size increasing from 63 m to 350 m toward the center of paleochannels however the well defined overbank facies is obscured by mutual erosion of individual flow units overlapping data fields in ternary grain size variation diagrams indicate the overbank facies to have evolved from ash flows chiefly through depletion of lapilli and coarse ash overbank facies ash layers do not represent dust layers resulting from elutriation clouds of ash flows co ignimbrite ash or surge deposits developed on higher ground due to low concentration of solids they are similar in some parameters to taupo type ignimbrite veneer deposits but are interpreted differently the thin fine grained laacher see ash layers are thought to have been deposited from diluted portions of the flow proceeding directly from the eruption column while the main pyroclastic flows were confined to the paleovalleys radiating away from the eruptive center the wide distribution of the thin ash layers is attributed to the balance of deposition from various flow parts and turbulent entraining and heating of ambient air that sustained sufficient mobility of the diluted flows to spread across hills and level ground

the 73 ka toba super eruption and its impact history of a debate abstract toba volcano in northern sumatra is located at the intersection of two major tectonic lineaments in one of the most seismically active regions in the world and its caldera is considered the largest quaternary caldera on earth the most recent toba explosive eruption at 73 ka was an order of magnitude larger than that of tambora in 1815 and has a volcanic explosivity index of 8 the exceptional magnitude of this super eruption and the widespread distribution of the younger toba tuff ytt in marine cores in the indian ocean the arabian sea and the south china sea have prompted sustained debate as to its global and regional impact on climate ecosystems and prehistoric human populations however despite climate modelling and appeals to a variety of proxy climatic data including geochemistry pollen analysis archaeology and stable isotopes the extent of the impact remains unclear in order to achieve better progress in the future greater care is needed to obtain higher resolution and more precise chronologies from the marine and terrestrial proxy records used to test whether or not the 73 ka toba super eruption had a significant environmental impact records from speleothems and ice cores have much to offer in this regard