formal definition and dating of the gssp global stratotype section and point for the base of the holocene using the greenland ngrip ice core and selected auxiliary records the greenland ice core from northgrip ngrip contains a proxy climate record across the pleistocene holocene boundary of unprecedented clarity and resolution analysis of an array of physical and chemical parameters within the ice enables the base of the holocene as reflected in the first signs of climatic warming at the end of the younger dryas greenland stadial 1 cold phase to be located with a high degree of precision this climatic event is most clearly reflected in an abrupt shift in deuterium excess values accompanied by more gradual changes in d 18 o dust concentration a range of chemical species and annual layer thickness a timescale based on multi parameter annual layer counting provides an age of 11 700 calendar yr b2 k before ad 2000 for the base of the holocene with a maximum counting error of 99 yr a proposal that an archived core from this unique sequence should constitute the global stratotype section and point gssp for the base of the holocene series epoch quaternary system period has been ratified by the international union of geological sciences five auxiliary stratotypes for the pleistocene holocene boundary have also been recognised copyright 2008 john wiley sons ltd

japan sea oxygen isotope stratigraphy and global sea level changes for the last 50 000 years recorded in sediment cores from the oki ridge abstract we obtained twenty ams accelerator mass spectrometry radiocarbon dates 2 tephra layer chronologies and a planktonic foraminiferal 18 o stratigraphy for the last 50 000 years from japan sea cores from the oki ridge in this paper we report ams 14 c results that allow us to reconstruct a high resolution chronology of the cores and discuss millennial scale climate changes recorded in japan sea sediments the sedimentation rate for the site increased dramatically from the glacial stage to the holocene as a result of significant hydrological changes associated with deglaciation and global sea level rise a lighter 18 o anomaly for the planktonic foraminifers was found during the lgm last glacial maximum this shift corresponds to a freshening of the japan sea surface waters and is mainly due to a global sea level drop rather than anomalously warm ssts sea surface temperatures as previously reported our record combined with the global sea level data suggests that the lgm started about 30 kyr ago and that the salinity of the japan sea became fresher than at present the ssts during mis marine oxygen isotope stage 3 were relatively stable and global sea level was not lower than ca 80 m the surface water of the japan sea attained normal saline levels following the younger dryas cold event and reached the present day 18 o values 7 kyr ago

a systematic comparison of obsidian hydration measurements the first application of micro image with secondary ion mass spectrometry to the prehistoric obsidian abstract archaeologists have long used obsidian hydration dating method to give chronometric dates for obsidian artifacts models using these equations independently employ different measurement systems which are based on rim thicknesses determined by optical microscope and hydrogen depths measured by secondary ion mass spectrometry sims respectively although the inconsistency of both measurements has been reported firstly this paper describes a systematic comparison that was done on optical rim thicknesses and hydrogen depths by means of an isotope microscope which provides micro imaging with sims depth profiles of hydrogen were precisely obtained from the spots where optical measurements were taken on the archaeological obsidian flakes from two distinctive cultural horizons older upper paleolithic younger initial jomon in the stratified open air site of jozuka in southern kyushu japan secondarily using the measurements of hydrogen depths that are the most consistent to the measurements of optical thicknesses the estimated hydration rate of the holocene initial jomon is slower than that of the late pleistocene upper paleolithic implying that the difference in hydration rates was due to the difference of intrinsic water content of obsidian and or obsidian geochemistry an application of micro imaging with sims to measure hydrogen depths on obsidian shows promise as a tool for improving the practice of hydration dating and evaluating local climatic condition

high spatial resolution electron probe microanalysis of tephras and melt inclusions without beam induced chemical modification wavelength dispersive analysis of tephra grains and melt inclusions by epma has been carried out using a focused beam of 3 m diameter without detected loss of sodium or potassium in standard glasses including anhydrous basalts a slightly hydrated rhyolite and a sodium rich intermediate composition the ability to make analyses without chemical modification is strongly dependent upon current density at the analysis site analysis with narrow beams requires extremely low beam currents that are normally associated with energy dispersive analysis experiments indicate that a value of 0 1 na m2 must not be exceeded at least for moderately hydrated samples if sodium loss is to be avoided high resolution analysis without beam induced analytical artefacts enables fully quantitative analysis of very distal and or highly vesicular tephras and very small melt inclusions without the need to use post analysis corrections this development has enabled high quality analyses from crypto tephra layers that were pre

constraints on the timing of explosive volcanism at aso and aira calderas japan between 50 and 30 ka new insights from the lake suigetsu sedimentary record sg14 core

new glass fission track ages of middle pleistocene tephras on yakushima island southern japan abstract the ages of two hornblende bearing middle pleistocene rhyolitic tephra beds on yakushima island southern japan have been determined by the glass itpft method koseda pyroclastic flow deposit is 0 58 0 08 ma and anbo tephra an is 0 78 0 09 ma the normal geomagnetic polarity of an demonstrates a stratigraphic position just above the bruhnes matuyama boundary both volcanic units are the result of large magnitude eruptions from a source that is most probably located at one of the calderas south of the central part of the kagoshima graben southern kyushu given the low total alkali content of their glass shards they must have been widely distributed across kyushu and central japan although no other occurrences are presently known new information on their mineralogy glass composition and age will greatly facilitate recognition of their distal correlatives although not explored in this study these two tephra beds will undoubtedly play a useful role in future studies aimed at elucidating the quaternary paleoenvironmental history of yakushima island

towards a climate event stratigraphy for new zealand over the past 30 000 years nz intimate project it is widely recognised that the acquisition of high resolution palaeoclimate records from southern mid latitude sites is essential for establishing a coherent picture of inter hemispheric climate change and for better understanding of the role of antarctic climate dynamics in the global climate system new zealand is considered to be a sensitive monitor of climate change because it is one of a few sizeable landmasses in the southern hemisphere westerly circulation zone a critical transition zone between subtropical and antarctic influences new zealand has mountainous axial ranges that amplify the climate signals and consequently the environmental gradients are highly sensitive to subtle changes in atmospheric and oceanic conditions since 1995 intimate has through a series of international workshops sought ways to improve procedures for establishing the precise ages of climate events and to correlate them with high precision for the last 30 000 calendar years the nz intimate project commenced in late 2003 and has involved virtually the entire new zealand palaeoclimate community its aim is to develop an event stratigraphy for the new zealand region over the past 30 000 years and to reconcile these events against the established climatostratigraphy of the last glacial cycle which has largely been developed from northern hemisphere records e g last glacial maximum lgm termination i younger dryas an initial outcome of nz intimate has been the identification of a series of well dated high resolution onshore and offshore proxy records from a variety of latitudes and elevations on a common calendar timescale from 30 000 cal yr bp to the present day high resolution records for the last glacial coldest period lgcp including the lgm sensu stricto and last glacial interglacial transition lgit from auckland maars kaipo and otamangakau wetlands on eastern and central north island marine core md97 2121 east of southern north island speleothems on northwest south island okarito wetland on southwestern south island are presented discontinuous fragmentary records comprising compilations of glacial sequences fluvial sequences loess accumulation and aeolian quartz accumulation in an andesitic terrain are described comparisons with ice core records from antarctica epica dome c and greenland gisp2 are discussed a major advantage immediately evident from these records apart from the speleothem record is that they are linked precisely by one or more tephra layers based on these new zealand terrestrial and marine records a reasonably coherent regionally applicable sequence of climatically linked stratigraphic events over the past 30 000 cal yr is emerging three major climate events are recognised 1 lgcp beginning at ca 28 000 cal yr bp ending at termination i ca 18 000 cal yr bp and including a warmer and more variable phase between ca 27 000 and 21 000 cal yr bp 2 lgit between ca 18 000 and 11 600 cal yr bp including a lateglacial warm period from ca 14 800 to 13 500 cal yr bp and a lateglacial climate reversal between ca 13 500 and 11 600 cal yr bp and 3 holocene interglacial conditions with two phases of greatest warmth between ca 11 600 and 10 800 cal yr bp and from ca 6 800 to 6 500 cal yr bp some key boundaries coincide with volcanic tephras copyright 2007 john wiley sons ltd

a tephra lattice for greenland and a reconstruction of volcanic events spanning 25 45 ka b2k tephra layers preserved within the greenland ice cores are crucial for the independent synchronisation of these high resolution records to other palaeoclimatic archives here we present a new and detailed tephrochronological framework for the time period 25 000 45 000 a b2k that brings together results from 4 deep greenland ice cores in total 99 tephra deposits the majority of which are preserved as cryptotephra are described from the ngrip neem grip and dye 3 records the major element signatures of single glass shards within these deposits indicate that 93 are basaltic in composition all originating from iceland specifically 43 originate from grimsvotn 20 are thought to be sourced from the katla volcanic system and 17 show affinity to the kverkfjoll system robust geochemical characterisations independent ages derived from the gicc05 ice core chronology and the stratigraphic positions of these deposits relative to the dansgaard oeschger climate events represent a key framework that provides new information on the frequency and nature of volcanic events in the north atlantic region between gs 3 and gi 12 of particular importance are 19 tephra deposits that lie on the rapid climatic transitions that punctuate the last glacial period this framework of well constrained time synchronous tie lines represents an important step towards the independent synchronisation of marine terrestrial and ice core records from the north atlantic region in order to assess the phasing of rapid climatic changes during the last glacial period

ages of 24 widespread tephras erupted since 30 000 years ago in new zealand with re evaluation of the timing and palaeoclimatic implications of the lateglacial cool episode recorded at kaipo bog abstract tephras are important for the nz intimate project because they link all three records comprising the composite inter regional stratotype developed for the new zealand climate event stratigraphy nz ces here we firstly report new calendar ages for 24 widespread marker tephras erupted since 30 000 calendar cal years ago in new zealand to help facilitate their use as chronostratigraphic dating tools for the nz ces and for other palaeoenvironmental and geological applications the selected tephras comprise 12 rhyolitic tephras from taupo nine rhyolitic tephras from okataina one peralkaline rhyolitic tephra from tuhua and one andesitic tephra each from tongariro and egmont taranaki volcanic centres age models for the tephras were obtained using three methods i 14 c based wiggle match dating of wood from trees killed by volcanic eruptions these dates published previously ii flexible depositional modelling of a high resolution 14 c dated age depth sequence at kaipo bog using two bayesian based modelling programs bacon and oxcal s p sequence function and the intcal09 data set with sh offset correction 44 17 yr and iii calibration of 14 c ages using oxcal s tau boundary function and the shcal04 and intcal09 data sets our preferred dates or calibrated ages for the 24 tephras are as follows youngest to oldest all mid point or mean ages of 95 probability ranges kaharoa ad 1314 12 taupo unit y ad 232 10 mapara unit x 2059 118 cal yr bp whakaipo unit v 2800 60 cal yr bp waimihia unit s 3401 108 cal yr bp stent unit q 4322 112 cal yr bp unit k 5111 210 cal yr bp whakatane 5526 145 cal yr bp tuhua 6577 547 cal yr bp mamaku 7940 257 cal yr bp rotoma 9423 120 cal yr bp opepe unit e 9991 160 cal yr bp poronui unit c 11 170 115 cal yr bp karapiti unit b 11 460 172 cal yr bp okupata 11 767 192 cal yr bp konini bed b 11 880 183 cal yr bp waiohau 14 009 155 cal yr bp rotorua 15 635 412 cal yr bp rerewhakaaitu 17 496 462 cal yr bp okareka 21 858 290 cal yr bp te rere 25 171 964 cal yr bp kawakawa oruanui 25 358 162 cal yr bp poihipi 28 446 670 cal yr bp and okaia 28 621 1428 cal yr bp secondly we have re dated the start and end of the lateglacial cool episode climate event nzce 3 in the nz ces previously referred to as the lateglacial climate reversal as defined at kaipo bog in eastern north island new zealand using both bacon and oxcal p sequence modelling with the intcal09 data set the ca 1200 yr long cool episode indicated by a lithostratigraphic change in the kaipo peat sequence to grey mud with lowered carbon content and a high resolution pollen derived cooling signal began 13 739 125 cal yr bp and ended 12 550 140 cal yr bp mid point ages of the 95 highest posterior density regions bacon modelling the oxcal modelling generating almost identical ages confirmed these ages the lateglacial cool episode ca 13 8 12 6 cal ka bp thus overlaps a large part of the entire antarctic cold reversal chronozone ca 14 1 12 4 cal ka bp or ca 14 6 12 8 cal ka bp and an early part of the greenland stadial 1 younger dryas chronozone ca 12 9 11 7 cal ka bp the timing of the lateglacial cool episode at kaipo is broadly consistent with the latitudinal patterns in the antarctic cold reversal signal suggested for the new zealand archipelago from marine and terrestrial records and with records from southern south america

fingerprints and age models for widespread new zealand tephra marker beds erupted since 30 000 years ago a framework for nz intimate abstract the role of tephras in the nz intimate project is a critical one because most high resolution palaeoclimatic records are linked and dated by one or more tephra layers in this review first we document eruptive distributional and compositional fingerprinting data both mineralogical and geochemical for 22 key marker tephras erupted since 30 000 years ago to facilitate their identification and correlation we include new glass compositional data the selected marker tephras comprise 10 from taupo and nine from okataina volcanoes rhyolitic one from tuhua volcano peralkaline rhyolitic and one each from tongariro and egmont volcanoes andesitic second we use four approaches to develop 2 age models for the tephras youngest to oldest 1 calendar ages for kaharoa and taupo y were obtained by wiggle matching log derived tree ring sequences dated by 14c 2 whakaipo v was dated using an age depth model from peat 3 14 tephras in the montane kaipo peat sequence waimihia s unit k whakatane tuhua mamaku rotoma opepe e poronui c karapiti b okupata konini waiohau rotorua rerewhakaaitu were dated by simultaneously wiggle matching stratigraphic position and 51 independent 14c age points against intcal04 using bayesian probability methods via both oxcal and bpeat and 4 the five oldest tephras erupted before ca 18 000 cal yr bp were dated by calibrating limited numbers of 14c ages using intcal04 okareka or comparison curves of the expanded cariaco basin sequence te rere kawakawa oruanui poihipi okaia kawakawa oruanui tephra the most widely distributed marker tephra was erupted probably ca 27 097 957 cal yr bp potential dating approaches for the older tephras include their identification in antarctic ice cores if present or annually laminated sediments for which robust calendar age models have been constructed high precision ams 14c dating on appropriate material from environmentally stable sites systematic luminescence dating or new radiometric techniques e g u th he if suitable minerals are available and errors markedly reduced further application of bayesian age modelling to stratigraphic sequences of 14c ages possibly augmented with luminescence ages may help refine age models for pre holocene tephras with the largest errors finally we discuss the critical role these marker tephras play in the ongoing construction of an event stratigraphy for the new zealand region which is a key objective of australasian and southern hemisphere intimate projects

identification and correlation of visible tephras in the lake suigetsu sg06 sedimentary archive japan chronostratigraphic markers for synchronising of east asian west pacific palaeoclimatic records across the last 150 ka abstract the lake suigetsu sg06 sedimentary archive from honshu island central japan provides a high resolution palaeoenvironmental record including a detailed record of explosive volcanism from japan and south korea thirty visible tephra are recorded within the 73 m long sg06 core which spans the last 150 ka here we describe and characterise these tephras based on major element glass composition which is useful for the identification and correlation of these tephras and the age models of the records in which they are found utilising the large number of radiocarbon measurements n 600 from terrestrial plant macrofossils in the lake suigetsu sg06 record we are able to provide precise and accurate ages for the tephras from eruptions within the last 50 ka glass compositional data of some of the largest eruptions from japan k ah at aso 4 aso a aso d and ata sampled at proximal outcrops are also presented these data show that the major element glass chemistry is distinctive for many of the visible sg06 tephra units and allows some of the layers to be correlated to known eruptions from volcanoes in japan and south korea namely k ah sg06 0967 u oki sg06 1288 at sg06 2650 aso 4 sg06 4963 sg06 4979 k tz sg06 5181 aso abcd sg06 5287 and ata sg06 5181 the following ages were obtained for the sg06 tephra units 3 966 4 064 cal ka bp 95 4 probability range for the sg06 0588 tephra 10 242 10 329 cal ka bp 95 4 probability range for sg06 1293 19 487 112 sg06 2012 ka bp 2 for sg06 1965 28 425 194 sg06 2012 ka bp 2 for sg06 2504 28 848 196 sg06 2012 ka bp 2 for sg06 2534 29 765 190 sg06 2012 ka bp 2 for sg06 2601 29 775 191 sg06 2012 ka bp 2 for sg06 2602 43 713 156 sg06 2012 ka bp 2 for sg06 3485 46 364 202 sg06 2012 ka bp 2 for sg06 3668 49 974 337 sg06 2012 ka bp 2 for sg06 3912 50 929 378 sg06 2012 ka bp 2 for sg06 3974 and improved ages for two of the most important tephra markers across japan the k ah 7 165 7 303 cal ka bp at 95 4 probability range sg06 0967 and at tephra 30 009 189 sg06 2012 ka bp at 2 sg06 2650

a composite pollen based stratotype for inter regional evaluation of climatic events in new zealand over the past 30 000 years nz intimate project abstract our review of paleoclimate information for new zealand pertaining to the past 30 000 years has identified a general sequence of climatic events spanning the onset of cold conditions marking the final phase of the last glaciation through to the emergence to full interglacial conditions in the early holocene in order to facilitate more detailed assessments of climate variability and any leads or lags in the timing of climate changes across the region a composite stratotype is proposed for new zealand the stratotype is based on terrestrial stratigraphic records and is intended to provide a standard reference for the intercomparison and evaluation of climate proxy records we nominate a specific stratigraphic type record for each climatic event using either natural exposure or drill core stratigraphic sections type records were selected on the basis of having very good numerical age control and a clear proxy record in all cases the main proxy of the type record is subfossil pollen the type record for the period from ca 30 to ca 18 calendar kiloyears bp cal ka bp is designated in lake bed sediments from a small morainic kettle lake galway tarn in western south island the galway tarn type record spans a period of full glacial conditions last glacial coldest period lgcp within the otira glaciation and includes three cold stadials separated by two cool interstadials the type record for the emergence from glacial conditions following the termination of the last glaciation post termination amelioration is in a core of lake sediments from a maar pukaki volcanic crater in auckland northern north island and spans from ca 18 to 15 64 0 41 cal ka bp the type record for the lateglacial period is an exposure of interbedded peat and mud at montane kaipo bog eastern north island in this high resolution type record an initial mild period was succeeded at 13 74 0 13 cal ka bp by a cooler period which after 12 55 0 14 cal ka bp gave way to a progressive ascent to full interglacial conditions that were achieved by 11 88 0 18 cal ka bp although a type section is not formally designated for the holocene interglacial 11 88 0 18 cal ka bp to the present day the sedimentary record of lake maratoto on the waikato lowlands northwestern north island is identified as a prospective type section pending the integration and updating of existing stratigraphic and proxy datasets and age models the type records are interconnected by one or more dated tephra layers the ages of which are derived from bayesian depositional modelling and oxcal based calibrations using the intcal09 dataset along with the type sections and the lake maratoto record important well dated terrestrial reference records are provided for each climate event climate proxies from these reference records include pollen flora stable isotopes from speleothems beetle and chironomid fauna and glacier moraines the regional composite stratotype provides a benchmark against which to compare other records and proxies based on the composite stratotype we provide an updated climate event stratigraphic classification for the new zealand region the stratotype and event classification are not intended to act as definitive statements of paleoclimate history for the new zealand region but rather provide a firm baseline against which to compare other records including those from the marine realm

establishing tephrostratigraphic frameworks to aid the study of abrupt climatic and glacial transitions a case study of the last glacial interglacial transition in the british isles c 16 8 ka bp abstract distally dispersed tephra layers have become an important tool in the investigation of palaeoenvironmental and archaeological records across the globe they offer possibilities for the synchronisation and improved chronological control in those records to which they can be traced and hence contribute to an improved understanding of the pattern and timing of environmental and archaeological change during periods of rapid climatic adjustment however their use as robust isochronous markers for synchronising records is frequently compromised by uncertainties relating to stratigraphical context precise chronology and chemical composition here we collate and review the tephrostratigraphical information dating to the last glacial interglacial transition lgit c 16 8 ka bp in the british isles based on published and unpublished records obtained from 54 sites based on details of their stratigraphic position chronology and chemical composition we propose that 26 individual eruption events may be represented in this collective record which spans the lgit the great majority of these eruptives can be traced in origin to iceland but we also report on the recent discoveries of ultra distal tephra from the north american cascades range including for the first time the mount st helens j tephra at a site in southern ireland these particular ultra distal discoveries have resulted from a reinterpretation of older data demonstrating the potential importance of unknown analyses in older tephra datasets the outcome of this review is a comprehensive but provisional tephrostratigraphic framework for the lgit in the british isles which helps to focus future research on parts of the scheme that are in need of further development or testing the results therefore make an important contribution to the wider european tephrostratigraphic framework while adding new discoveries of transcontinental isochronous tephra markers

developing a holocene tephrostratigraphy for northern japan using the sedimentary record from lake kushu rebun island abstract palaeoclimate records in east asia offer significant potential to further our understanding of monsoon dynamics and can serve as a link between north atlantic and tropical climate systems the sedimentary core from lake kushu rebun island provides the first high resolution palaeoclimate record from northern japan in order for this regionally significant archive to be synchronised to other records and to generate a more detailed holocene tephra lattice for east asia we present the first cryptotephra stratigraphy for northern japan using the kushu rk12 core the detailed rk12 tephrostratigraphy integrates local and far travelled tephras originating from japan russia china north korea and most likely indonesia five key cryptotephra layers have been identified precisely dated and correlated to the specific eruptions or the source region b tm tephra changbaishan volcano sh 12 tephra shiveluch volcano ko g tephra komagatake volcano ma f j tephra mashu volcano and rk12 0819 tephra with possible indonesian origin these tephra horizons are very widely dispersed providing opportunities to synchronise distant palaeoclimate records from the polar region through high northern latitudes to the tropics which facilitate interregional comparison of palaeoclimate and environmental data in addition a number of the geochemically analysed horizons contain other minor numbers of compositionally distinct glass which can also be grouped and correlated to their source volcanoes these minor analyses are of interest since they provide new insight into regional tephra dispersal e g ash dispersal potential of aira and towada and could suggest that there are other potential eruptions that have yet to be identified in the geological record e g potential changbaishan eruptions the integrated lake kushu cryptotephra record extends the ash dispersal of several key tephra horizons in the region the presence of the shiveluch sh 12 tephra in lake kushu ca 1900 km away documents the first example of a russian tephra reaching the japanese archipelago furthermore glass compositions suggest that the core could preserve an eruption event derived from indonesia highlighting the future possibility to significantly extend and interlink the tephra lattice across the entirety of asia this is an essential step for the understanding of how climate changes propagate over large geographical areas indeed several of these tephra markers coincide with significant ecological changes reflected in the pollen proxy record at lake kushu using this high resolution palaeoenvironmental record we however find no significant ecological impact following the large late holocene millennium eruption from changbaishan china north korea

integrating the holocene tephrostratigraphy for east asia using a high resolution cryptotephra study from lake suigetsu sg14 core central japan abstract tephra volcanic ash layers have the potential to synchronise disparate palaeoenvironmental archives on regional to hemispheric scales highly productive arc regions like those in east asia offer a considerable number of widespread isochrons but before records can be confidently correlated using these layers a refined and integrated framework of these eruptive events is required here we present the first high resolution holocene cryptotephra study in east asia using the lake suigetsu sedimentary archive in central japan the holocene tephrostratigraphy has been extended from four to twenty ash layers using cryptotephra extraction techniques which integrates the deposits from explosive eruptions from north korea china south korea and along the japanese arc this lake suigetsu tephrostratigraphy is now the most comprehensive record of east asian volcanism and the linchpin site for correlating sequences across this region major element glass geochemical compositions are presented for the tephra layers in the sequence which have been compared to proximal datasets to correlate them to their volcanic source and specific eruptions this study has significantly extended the ash dispersal of many key holocene marker layers and has identified the first distal occurrence of isochrons from ulleungdo and changbaishan volcanoes utilising the high precision lake suigetsu chronology we are able to provide constrained eruption ages for the tephra layers which can be transferred into other site specific age models containing these markers this new framework indicates that several isochrons stratigraphically bracket abrupt climate intervals in japan and could be used to precisely assess the regional and hemispheric synchronicity of these events

modelling the impact of a hypothetical sub plinian eruption at la soufriere of guadeloupe lesser antilles abstract this paper describes the development and application of an impact model for a future hypothetical sub plinian eruption of la soufriere of guadeloupe the model was designed to assess the impact from either a single or multiple eruption scenarios each defined in terms of a map of the intensity of three volcanic hazards volcanogenic earthquake tephra fallout and pyroclastic density currents the impact from the three hazards can be assessed independently or alternatively the joint impact of the three hazards can be assessed the outputs that are produced from the model are the number of buildings with collapsed roofs and the number of fatal and non fatal casualties two versions of the impact model were developed one that uses a spreadsheet and another that is implemented using a geographical information system gis both versions use the same types of hazard inputs and vulnerability functions to derive the number of building collapses and casualties but have different spatial resolution of the final outputs the spreadsheet version aggregates the results at a zone level defined specifically for this project whereas the gis was designed to produce results using 250 m grid squares the outputs from the two versions when using the same eruption scenario produced somewhat different results highlighting the importance of defining the appropriate spatial resolution the vulnerability functions were developed using data on the building stock that was collected by a local survey in which data on the form of construction condition location and types of openings and the variation of these parameters across the affected area were collected the vulnerability functions incorporated new assessments of fire risks induced by pyroclastic density currents the model was applied to la soufriere using a range of input hazard scenarios based on reconstruction of the most recent sub plinian magmatic eruption which occurred in 1530 ad a sensitivity analysis of the model was carried out choosing the inputs from a range of defined input values the effect on losses and casualties of a range of possible mitigation measures was assessed by running the original model and the modified model using the same input eruption scenario a separate casualty treatment model was also developed and tested

late quaternary cryptotephra detection and correlation in loess in northeastern japan using cummingtonite geochemistry abstract we detected late pleistocene cummingtonite bearing cryptotephras in loess deposits in ne japan and correlated them with known tephras elsewhere by using major element compositions of the cummingtonite this is the first time cryptotephras have been identified by analysis of a crystal phase rather than glass shards in central ne japan four cummingtonite bearing tephras the ichihasama pumice the dokusawa tephra the naruko nisaka tephra and the adachi medeshima tephra are present in late pleistocene loess deposits because the cummingtonite chemistry of each tephra is different and characteristic it is potentially a powerful tool for detecting and identifying cryptotephras an unidentified cummingtonite bearing cryptotephra previously reported to be present in the late pleistocene loess deposits at kesennuma pacific coast did not correlate with any of the known cummingtonite bearing tephras in central ne japan but instead with the numazawa kanayama tephra erupted from the numazawa caldera southern ne japan although kesennuma is well beyond the previously reported area of the distribution of the numazawa kanayama tephra three new cummingtonite bearing cryptotephras in the mid and late pleistocene loess deposits estimated to be less than 82 ka 100 200 ka and ca 250 ka on the isawa upland were also detected

radiocarbon dating of tephra layers recent progress in japan abstract a large number of tephra layers deposited over the past 40 000 years in japan have been studied by means of newly developed techniques as well as the traditional radiocarbon 14 c method the samples for 14 c dating were commonly charcoal and wood directly covered or involved in tephra fall and pyroclastic flow deposits recently the 14 c dates measured for paleosols directly underlying a tephra layer have proved to represent the accurate eruption age of the tephra and have successfully established the high resolution eruptive histories of several volcanoes in addition oceanic and lacustrine sediments have preserved a large number of tephra layers and accelerator mass spectrometry 14 c measurements on terrestrial macrofossils from varved sediments have provided highly accurate ages for tephra layers wiggle matching of 14 c ages from several horizons of peat sediments to intcal98 calibration data that was established by dendrochronology as well as by varve chronology has enabled us to obtain highly accurate ages of tephras intercalated in the peat deposits

late quaternary phreatomagmatic tephra layers and their relation to paleo sea levels in the area of aira caldera southern kyushu japan abstract four late quaternary phreatomagmatic eruptions occurred during different sea levels and paleoenvironments as determined by study of four tephra units containing fine grained ash layers and their relation to coastal features in the aira caldera volcanic area these units are 1 aira ito 22 000 bp 2 sakurajima satsuma 11 000 bp 3 sumiyoshiike 6700 7000 bp and 4 yonemaru 6500 6700 bp formations these formations contain base surge deposits as well as fine grained ash fall from phreatomagmatic eruptions the eruptions occurred under very different conditions of sea level heights and coastal environments the aira ito eruption occurred during the lowest sea level stage the sakurajima satsuma eruption during rapid sea level rise and the sumiyoshiike and yonemaru eruptions during the final sea level transgression the sea level heights relative to present sea level are 60 m and 20 m below and 10 15 m above respectively

a north atlantic tephrostratigraphical framework for 130 60 ka b2k new tephra discoveries marine based correlations and future challenges abstract building chronological frameworks for proxy sequences spanning 130 60 ka b2k is plagued by difficulties and uncertainties recent developments in the north atlantic region however affirm the potential offered by tephrochronology and specifically the search for cryptotephra here we review the potential offered by tephrostratigraphy for sequences spanning 130 60 ka b2k we combine newly identified cryptotephra deposits from the ngrip ice core and a marine core from the iceland basin with previously published data from the ice and marine realms to construct the first tephrostratigraphical framework for this time interval forty three tephra or cryptotephra deposits are incorporated into this framework twenty three tephra deposits are found in the greenland ice cores including nine new ngrip tephras and twenty separate deposits are preserved in various north atlantic marine sequences major minor and trace element results are presented for the new ngrip horizons together with age estimates based on their position within the ice core record basaltic tephras of icelandic origin dominate the framework with only eight tephras of rhyolitic composition found new results from marine core md99 2253 also illustrate some of the complexities and challenges of assessing the depositional integrity of marine cryptotephra deposits tephra based correlations in the marine environment provide independent tie points for this time interval and highlight the potential of widening the application of tephrochronology further investigations however are required that combine robust geochemical fingerprinting and a rigorous assessment of tephra depositional processes in order to trace coeval events between the two depositional realms

the role of tephras in developing a high precision chronostratigraphy for palaeoenvironmental reconstruction and archaeology in southern kyushu japan since 30 000 cal bp an integration abstract tephras are important for the chronostratigraphy of palaeoenvironmental and archaeological records in southern kyushu because numerous tephra beds enable these records to be connected and dated precisely using tephrochronology a regional tephra based framework or lattice for the past 30 000 calendar cal years is proposed in the style of recent intimate projects elsewhere we review stratigraphic compositional age and distributional data for a range of tephras and comment on the relationship of several marker tephras to distinct palaeoenvironmental and cultural events in the southern kyushu region since 30 000 cal bp more than 90 visible tephra beds are recorded deriving from kakuto aira ata and kikai volcanic centres which incorporate large calderas and the tokara volcanic islands the tephra record is underpinned by two widespread tephras aira tn tephra at ca 30 000 cal bp and kikai akahoya tephra k ah ca 7300 cal bp in addition to at and k ah locally distributed marker tephra beds are related to the chronostratigraphy of terrestrial and marine palaeoenvironments including sea level and coastal environments vegetation and culture some tephras notably at k ah and sakurajima satsuma tephra sz s ca 12 800 cal bp have been recognized in marine and laminated lake sediments and hence dated with high precision thereby facilitating correlation of those records to global high resolution ice marine and terrestrial stratotypes sz s is a useful isochron for the last deglaciation in southern kyushu our integrated regional chronostratigraphic model for southern kyushu founded by tephras and with further potential via systematic identification of cryptotephras will enable change in regional palaeoenvironments and culture to be evaluated in national and global contexts

middle to late holocene delta plain evolution of the kimotsuki lowland kyushu southern japan abstract the evolution of delta plains and coastal floodplains is commonly believed to be influenced by sea level and climate changes however regional climate change influences on the evolution of delta plains and floodplains are poorly understood compared with responses to rapid sea level rise since the last deglaciation this study investigated the kimotsuki lowland delta plain evolution kyusyu southern japan including allogenic controls based on 28 auger cores and 28 radiocarbon ages large scale crevasse splay deposition occurred at 7000 6000 cal yr bp in response to sea level rise or increased sediment supply following a volcanic eruption afterwards widespread peat was formed in the absence of substantial fluvial sedimentation decreased precipitation from a weakened east asian summer monsoon may have dried the peatlands around 4000 cal yr bp with increasing precipitation and storminess around 2000 cal yr bp peat formation resumed at areas further from the kimotsuki river while increased overbank flows deposited organic rich mud near the river these changes may reflect an increased frequency of la nina events and higher ocean surface temperatures of the kuroshio extension the increased storminess around 2000 cal yr bp may have produced similar influences on delta plain and coastal floodplain evolution across the east asia region the results of this study suggest that regional climate change in the late holocene has a potential to control the evolution of coastal floodplains and delta plains

pollen event stratigraphy of the varved sediment of lake suigetsu central japan from 15 701 to 10 217 sg vyr bp suigetsu varve years before present description interpretation and correlation with other regions high resolution pollen data average interval between samples 15 years are reported on part of a varved sediment core from lake suigetsu japan spanning the interval 15 701 to 10 217 sg vyr bp suigetsu varve years before present this new record is compared with a previously proposed event stratigraphy based on pollen based reconstructed changes of mean annual temperature the deglacial climate history reconstructed at lake suigetsu resembles that observed in the north atlantic although the major boundaries of pollen zones are asynchronous with those in the north atlantic event stratigraphy by several centuries the onset of the late glacial interstadial occurred earlier in japan than in the north atlantic this demonstrates that the climate in japan was closely linked to the low latitude pacific sea surface temperatures that first reacted to orbital forcing conversely the onset of the subsequent cold reversal phase in japan lagged that of the north atlantic younger dryas by several centuries the duration of this cold phase was about the same as the younger dryas event but the amplitude was much reduced 4 2 c in mean annual temperature these findings support the hypothesis that this pan hemispheric cooling event was triggered by north atlantic forcing most probably by a meltwater pulse and an associated change in the north atlantic thermohaline circulation however the mechanism which transmitted the change in the north atlantic to the far east is unknown

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

holocene tephrostratigraphic framework and monsoon evolution of east asia key tephra beds for synchronising palaeoclimate records abstract in east asia our understanding of holocene climate change forcing mechanisms and propagation require the precise chronological control of palaeoclimate records to allow robust integration of data sets the existing chronologies predominantly based on 14c method however are not sufficient to constrain key questions about abrupt climate shifts that occur within a century in the transitions between states widely dispersed tephra layers allow precise dating and synchronisation of sedimentary archives providing a chronological framework for integrating records especially where the visible tephra record is complemented by the addition of cryptotephra non visible ash despite significant tephra studies in this region however a comprehensive holocene tephra framework is not available to address this issue we carry out a thorough review on holocene tephra investigations undertaken in japan using widespread tephra beds we present an integrated tephra framework and suggest the way forward for establishing this as a wider approach for east asia the framework is based on twenty two ash layers that are mainly from japan and to a lesser extent china n korea s korea and russia each tephra is assessed in terms of chronology geochemistry and distribution the framework is compared with high resolution palaeoclimate records from east asia using this we demonstrate regional variations in monsoon evolution and more importantly the potential of tephra isochrons in constraining such variations given the scarce identification of tephra layers in those well resolved palaeoclimate records we advocate a more systematic employment of the cryptotephra method which would potentially lead to a significant advance in east asian tephrochronology and the correlation of palaeoclimate archives in the region

cooling and crystallization recorded in trachytic enclaves hosted in pantelleritic magmas pantelleria italy implications for pantellerite petrogenesis abstract this study focuses on the comenditic trachyte enclaves hosted in pantelleritic lava and pumices emplaced during one of the most recent eruptive events at pantelleria 6 ka enclaves range from mm sized fragments to dm sized blocks with spheroidal to amoeboid shapes and characteristic globular surfaces they are crystal rich with 30 vol large anorthoclase less abundant fe rich olivine clinopyroxene and fe ti oxides vesicles ranging from a few mm to 1 2 cm in size are distributed throughout the enclave and are commonly filled with microlite free vesicular glass the groundmass presents spectacular textures including fine to coarse spherulites and hopper and skeletal microlites mostly anorthoclase with 10 35 vol residual glass and 10 15 vol small vesicles 2 accordingly the microlite composition is close to that of the host pantellerite these textures were acquired during a magma mixing event prior to the eruption i a vapor saturated comenditic trachyte magma intruded the shallower cooler pantellerite magma body triggering a first degassing event first boiling and rapid crystallization with a high degree of undercooling t 100 150 c ii vapor exsolution induced by rapid crystallization second boiling produced the microvesicular groundmass and iii vapor pressure forced the residual pantelleritic liquid to migrate into the large vesicles and or outside the enclaves based on this interpretation these enclaves can be used as a natural laboratory for identifying the chemical and physical processes driving the evolution of silicic magmas at pantelleria in particular they can be used to assess whether pantellerite melts can be obtained from comenditic trachytes after extensive crystallization followed by gas driven filter pressing and consequent pantellerite melt segregation

characterization and correlation of cryptotephras using major element analyses of melt inclusions preserved in quartz in last interglacial marine sediments southeastern shikoku japan although sediments underlying marine terraces in se shikoku southwest japan contain no visible tephra layers late pleistocene cryptotephras were detected in a paleosol within the sediments the cryptotephras contained little or no glass but they were characterized through major element analyses of glass preserved as melt inclusions in quartz grains extracted from the paleosol the analyses enabled correlation of the cryptotephras with known eruptives from volcanoes on kyushu namely the kikai tozurahara tephra mis 5 2 5 3 the aira tn tephra 28 6 cal ka and the kikai akahoya tephra 7 5 cal ka these correlations enabled dating of the marine terrace surface known as the murotomisaki 1 surface in se shikoku as being older than mis 5 2 5 3 probably mis 5 5 in age in the absence of glass or mafic minerals because of weathering the analysis of melt inclusions in resistant quartz grains demonstrably provides a powerful method for characterizing cryptotephras to facilitate their correlation and thus their application as a linking and dating tool

detection and correlation of widespread cryptotephras in middle pleistocene loess in ne japan using cummingtonite geochemistry we used cummingtonite chemistry to detect strongly weathered widespread cryptotephras within middle pleistocene loess and fluvial terrace deposits and to correlate them with previously reported tephras in central and ne japan we correlated a cummingtonite bearing cryptotephra widely distributed in ne japan below the ichihasama pumice 108 146 ka and above the iwadeyama pumice iwp 160 240 ka with the iizuna kamitaru c tephra iz ktc which erupted from iizuna volcano central japan iz ktc is thus a widespread middle pleistocene tephra covering both central and ne japan moreover we detected the adachi medeshima tephra ac md which had been previously inferred to be a late pleistocene tephra 80 100 ka below the iz ktc and iwp tephras 125 150 ka and above the hagimori white ash tephra 210 250 ka therefore ac md must be a middle pleistocene tephra with an eruptive age older than 125 150 ka and younger than 210 250 ka we also detected a cummingtonite bearing tephra older than 210 250 ka and younger than 250 300 ka in the isawa area of ne japan and correlated it with a previously reported tephra in central japan thus like iz ktc this tephra is a widespread middle pleistocene tephra

a revised age for the kawakawa oruanui tephra a key marker for the last glacial maximum in new zealand abstract the kawakawa oruanui tephra kot is a key chronostratigraphic marker in terrestrial and marine deposits of the new zealand nz sector of the southwest pacific erupted early during the last glacial maximum lgm the wide distribution of the kot enables inter regional alignment of proxy records and facilitates comparison between nz climatic variations and those from well dated records elsewhere we present 22 new radiocarbon ages for the kot from sites and materials considered optimal for dating and apply bayesian statistical methods via oxcal4 1 7 that incorporate stratigraphic information to develop a new age probability model for kot the revised calibrated age 2 standard deviations for the eruption of the kot is 25 360 160 cal yr bp the age revision provides a basis for refining marine reservoir ages for the lgm in the southwest pacific

tephrochronology and eruptive history of kirishima volcano in southern japan abstract kirishima volcano has been active for the last 600 ka from 600 to 330 ka the activity mainly consisted of caldera forming eruptions with two large scale pyroclastic flows of 50 km3 in dense rock equivalent dre from 600 ka to present 83 of the discharged magma has erupted as pyroclastic materials after 330 ka volcanic activity changed and stratovolcanoes started to be constructed with fallout tephras from plinian vulcanian strombolian and phreatomagmatic eruptions eruptive centers have roughly migrated from west to east forming more than 25 small scale stratovolcanoes and pyroclastic cones the magma discharge rate has increased from 0 05 to 0 6 km3 ky kirishima is becoming increasingly more active and a more accurate and detailed warning system for its eruptions is required

cryptotephras the revolution in correlation and precision dating from its icelandic origins in the study of visible tephra horizons tephrochronology took a remarkable step in the late 1980 s with the discovery of a ca 4300 year old microscopic ash layer in a scottish peat bog since then the search for these cryptotephra deposits in distal areas has gone from strength to strength indeed a recent discovery demonstrates how a few fine grained glass shards from an alaskan eruption have been dispersed more than 7000 km to northern europe instantaneous deposition of geochemically distinct volcanic ash over such large geographical areas gives rise to a powerful correlation tool with considerable potential for addressing a range of scientific questions a prerequisite of this work is the establishment of regional tephrochronological frameworks that include well constrained age estimates and robust geochemical signatures for each deposit with distal sites revealing a complex record of previously unknown volcanic events frameworks are regularly revised and it has become apparent that some closely timed eruptions have similar geochemical signatures the search for unique and robust geochemical fingerprints thus hinges on rigorous analysis by electron microprobe and laser ablation inductively coupled plasma mass spectrometry historical developments and significant breakthroughs are presented to chart the revolution in correlation and precision dating over the last 50 years using tephrochronology and cryptotephrochronology

zircon u pb dating using la icp ms quaternary tephras in yakushima island japan abstract zircon u pb dating using la icp ms was applied to three quaternary tephras in yakushima island southern japan the anbo tephra the koseda pyroclastic flow deposit ksd and the kikai tozurahara k tz tephra the obtained u pb ages were 0 73 0 04 ma error shown as 95 confidence level for the anbo 0 63 0 04 ma for the ksd and 0 17 0 05 ma for the k tz these ages are consistent with or slightly older than those reported previously which demonstrates the applicability of the u pb method to date zircons as young as 0 1 ma the k tz contains 0 7 0 6 ma zircons assumed to be derived from the anbo and ksd tephras because the k tz was originated from the kikai caldera 30 km north of yakushima island both the anbo and ksd were likely also derived from the same caldera system therefore our data and interpretation will contribute to elucidate the magmatic history of the kikai caldera whose latest eruption devastated prehistoric human settlements of southern kyushu japan and provide an improved chronostratigraphic constraint for japan

towards a protocol for the trace element analysis of glass from rhyolitic shards in tephra deposits by laser ablation icp ms laser ablation inductively coupled plasma mass spectrometry la icp ms is used widely to analyse single volcanic glass shards from quaternary tephra deposits for stratigraphic correlation as yet no generally accepted protocol for these analyses exists and published methods report significant differences in crater size and calibration strategies using ca as the internal standard cai s and not sii s for the analysis of rhyolitic glass can cause significant problems because of ablation of i ca rich phenocrysts notably ubiquitous plagioclase but also calcic amphibole apatite and allanite or ii mounting epoxy resin which can contribute to the ca internal standard signal using cai s can cause underreporting of many elements which concentrate in ca rich phenocrysts making their ablation difficult to recognize but when using sii s no such underreporting occurs additionally larger ablation craters 50 m diameter potentially incorporate even small volumes of phenocryst material whereas smaller craters 20 m diameter more frequently miss phenocrysts thus for the la icp ms analysis of rhyolitic glass shards smaller ablation craters should be employed and calibrated using sii s allowing recognition and removal of analyses incorporating ca rich phenocrysts and avoiding issues related to the ablation of the mounting resin

synchronisation of palaeoenvironmental records over the last 60 000 years and an extended intimate event stratigraphy to 48 000 b2k the intimate protocol for the correlation of marine ice core and terrestrial records is here updated reflecting recent developments in palaeoclimate research originally focussed on last glacial to interglacial transition lgit 22 000 11 500 years b p the intimate group has now extended its study period back to 60 000 years as a first step the intimate event stratigraphy has now been extended to include 8000 48 000 b2k based on a combined ngrip and grip isotope profile against a gicc05 chronology and key tephra horizons from iceland and continental european volcanic sources in this lead article of this intimate special issue we introduce some of the recent achievements of the intimate community and discuss the challenges associated with extending the intimate approach back in time focussing in particular on the chronological problems inherent in comparing different proxy records the intimate approach has thus far been limited predominantly to the north atlantic and australasian regions and we also discuss the potential to extend the intimate protocol beyond these regions

prospects and pitfalls in integrating volcanology and archaeology a review abstract volcanic eruptions and interactions with the landforms and products these yield are a constant feature of human life in many parts of the world seen over long timespans human volcano interactions become stratified in sedimentary archives containing eruptive products and archaeological remains this review is concerned with charting the overlapping territory of volcanology and archaeology and attempts to plot productive routes for further conjoined research we define archaeological volcanology as a field of study that brings together incentives insights and methods from both volcanology and from archaeology in an effort to better understand both past volcanism as well as past cultural change and to improve risk management practices as well as the contemporary engagement with volcanism and its products there is an increasing appreciation that understanding these human impacts and manifold human volcano interactions requires robust multi inter or even trans disciplinary collaboration our review is written in the hope of providing a clearinghouse resource that i maps the many forms of past human volcano interactions ii provides study design templates for how to integrate archaeological perspectives into investigations of past volcanism and iii makes suggestions for how the insights gained from such an archaeological volcanology can be integrated into reducing contemporary and future vulnerability amongst at risk communities

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

paleoenvironmental changes in the northern area of the east china sea during the past 42 000 years a 33 65 m long images md982195 core with very high sedimentation rate ca 80 cm kyr retrieved from the northern part of the east china sea was analyzed at 10 cm intervals about 125 years for oxygen carbon isotope of globigerinoides ruber sensu stricto sea surface temperature sst from alkenones u37 k and principal component analysis of planktonic foraminiferal assemblage the general pattern of the 18o curve resembling the alkenone sst curve is similar to the standard open ocean oxygen isotope curve it reveals many light 18o peaks apparently corresponding to dansgaard oeschger d o cycles as observed in greenland ice cores for the last 42 ka the alkenone sst at the core top is 24 c which is close to the modern annual mean sst around the core site on the other hand sst during the last glacial maximum lgm was about 5 c lower than that in the present day alkenone derived sst does not correlate with the light negative 18o peaks corresponding to the d o cycles the oxygen isotope ratios for the surface waters based on oxygen isotopes of g ruber and alkenone ssts indicate approximately 1 0 increase on average during the lgm and many light peaks at the warm d o events this suggests that fresh water was supplied to the core site during these events the meandering of the westerlies during the cold and warm d o cycles would have caused an atmospheric tele connection between east asia and greenland the core was divided into four periods based on q mode factor analysis of the planktonic foraminiferal assemblage i e 1 a strong upwelling period from 42 to 24 ka indicated by abundant occurrence of globigerina bulloides 2 a cold and low salinity water mass period from 24 to 14 ka suggested by increase of neogloboquadrina pachyderma neogloboquadrina incompta and globigerina quinqueloba 3 a transitional period from cold to warm water masses from 14 to 8 ka as indicated by the increase of warm water species such as pulleniatina obliquiloculata and globigerinoides ruber and 4 the present day warm kuroshio current condition after 8 ka the kuroshio current flowed into the ecs since the last 42 ka and weakened during the last glacial maximum lgm due to the expansion of the coastal water in the northern part of the ecs

a new scenario for the last magmatic eruption of la soufriere of guadeloupe lesser antilles in 1530 a d evidence from stratigraphy radiocarbon dating and magmatic evolution of erupted products la soufriere of guadeloupe is a dangerous volcano characterized over the last decade by moderate seismic and fumarolic unrest in the last 15 000 years it has experienced phreatic and magmatic eruptions and unusually numerous flank collapse events sometimes associated with a magmatic eruption we propose a new age of 1530 a d and a new eruptive scenario for the last magmatic eruption on the basis of a novel statistical analysis of radiocarbon age dates and new field and geochemical data this eruption is the only magmatic eruption likely to have occurred in guadeloupe during the last 1400 years the eruption mainly involved an andesitic magma which in the first phase of the eruption partially mixed with a slightly more differentiated magma stored in a small and shallow magma chamber ascent of magma to the surface generated a partial collapse of the hydrothermally altered edifice that increased the magma discharge and led to a sub plinian phase with scoria fallout and column collapse pyroclastic flows followed by near vent pyroclastic scoria fountains the eruption ended with growth of a lava dome our revised interpretation of the last magmatic eruption of la soufriere constitutes the most likely key to a future magmatic eruption scenario for this volcano which displays strong evidence of unrest since 1992

integrating the intimate records using tephrochronology rising to the challenge little has challenged our understanding of climate change more so than the abruptness with which large scale shifts in temperature occurred during the late quaternary the causal mechanisms driving

late pleistocene and holocene tephrostratigraphy of interior alaska and yukon key beds and chronologies over the past 30 000 years abstract the aleutian arc alaska peninsula and wrangell volcanic field are the main source areas for tephra deposits found across alaska and northern canada and increasingly tephra from these eruptions have been found further afield in north america greenland and europe however there have been no broad scale reviews of the late pleistocene and holocene tephrostratigraphy for this region since the 1980s and this lack of data is hindering progress in identifying these tephra both locally and regionally to address this gap and the variable quality of associated geochemical and chronological data we undertake a detailed review of the latest pleistocene to holocene tephra found in interior alaska and yukon this paper discusses nineteen tephra that have distributions beyond southwest alaska and that have the potential to become or already are important regional markers this includes three modern events from the 20th century ten with limited data availability but potentially broad distributions and six that are widely reported in interior alaska and yukon each tephra is assessed in terms of chronology geochemistry and distribution with new bayesian age estimates and geochemical data when possible this includes new major element geochemical data for crater peak 1992 redoubt 1989 90 and two andesitic tephra from st michael island tephra d as well as revised age estimates for dawson tephra oshetna hayes set h aniakchak cfe ii and the white river ashes northern and eastern lobes

sakurajima satsuma sz s and noike yumugi n ym tephras new tephrochronological marker beds for the last deglaciation southern kyushu japan abstract two prominent tephras sakurajima satsuma sz s erupted from sakurajima volcano and noike yumugi n ym erupted from kuchierabujima island provide new key marker beds for dating and synchronizing palaeoenvironmental and archaeological records in the last deglaciation in southern japan these tephras were identified on the basis of glass major element compositions in two distal areas a marine core images md982195 in the northern part of the east china sea and on the central part of tanegashima island and we related their stratigraphic positions to the marine oxygen isotope based chronology in md982195 sz s 0 8 cm in thickness at 9 12 m depth and n ym 3 cm in thickness at 9 30 m depth are both white vitric ash grade tephras on tanegashima island sz s 10 cm in thickness and n ym 3 cm in thickness are stratigraphically constrained by well characterised marker tephras kikai akahoya 7300 cal bp and aira tn 29 000 cal bp sz s is rhyolitic and homogeneous on the basis of glass major element compositions assayed by electron microprobe pumiceous glass shards predominant in distal sz s tephra indicate that it derived from pumice fall units that correspond to pumiceous and phreatomagmatic fine ash units constituting proximal sz s tephra n ym is rhyolitic and glass major element analyses reveal compositional diversity between units suggesting that the lower and middle tephra units dispersed to the east whereas the upper unit was dispersed north to northwest from the vent stratigraphically sz s occurs at around the start of the late glacial reversal cooling in oxygen isotope records of md982195 corresponding to the end of gi 1 and the start of gs 1 in the ice core events of ngrip gicc05 consistent with a terrestrial age of 12 800 cal bp based on the oxygen isotope stratigraphy the tephra identified in the core as n ym at 9 30 m depth is close to the end of greenland gi 1 and hence has an age of 13 000 cal bp but on kuchierabujima island it has an age based on 14 c assay of charcoal of c 14 900 cal bp although this age discrepancy 14 9 vs 13 0 cal ka needs resolution the occurrence in core md982195 of n ym shows that it is more widespread than hitherto demonstrated the widespread distributions and key stratigraphic positions for the two marker tephras indicate that they are thus critical isochrons for precise correlation of palaeoenvironmental changes and prehistoric cultural events during the last deglaciation in southern kyushu and for relating such changes and events to the ice core chronology via the marine oxygen isotope chronostratigraphy

鬼界アカホヤテフラ k ah の年代と九州縄文土器編年との対応関係