variations in mode of formation and temperature of oceanic deep waters over the past 125 000 years marked changes in the deep water temperature of the different oceanic basins during the past 125 kyr are revealed by a detailed comparison of the oxygen isotopic composition ofbenthicforaminiferafrom sediment cores taken from the norwegian sea and the pacific atlantic and southern oceans the last interglacial deep water temperatures were similar to the modern ones at the 5e 5d transition around 115 kyr bp the deep water temperatures dropped below approximately 0 c in the pacific and southern indian oceans in the atlantic ocean the deep water temperature dropped in 2 successive steps at 115 and 75ky bp the global ocean deep water temperatures were in the 0 to 1 c range for the whole of the last ice age isotope stages 4 2

origin of the lethal gas burst from lake monoun cameroun abstract on 15 august 1984 a lethal gas burst issued from a submerged 96 m deep crater in lake monoun in cameroun western africa killing 37 people the event was associated with a landslide from the eastern crater rim which slumped into deep water waters below 50 m are anoxic dominated by high fe 2 600 mg l and hco 3 1900 mg l anoxic and supersaturated with siderite which is a major component of the crater floor sediments the unusually high fe 2 levels are attributed to reduction of laterite derived ferric iron gradually brought into the lake as loess and in river input sulfur compounds are below detection limits in both water and gas gases effervescing from depressurized deep waters are dominantly co 2 with minor ch 4 having 13 c of 7 18 and 54 8 per mil respectively bacterial decomposition of organic matter may account for the methane but 14 c of lake water indicates that only 10 of the carbon is modern giving an apparent age of 18 000 years the dominant source of carbon is therefore attributed to long term emission of co 2 as volcanic exhalation from vents within the crater which led to gradual build up of hco 3 in the lake the density stratification of the lake may have been upset by an earthquake and underwater landslide on 15 august which triggered overturn of the lake and caused nucleation of co 2 in the deep water the resultant ebullition of co 2 from deep lake waters led to a gas burst at the surface and locally generated a water wave up to 5 m high people travelling through the gas cloud were asphyxiated presumably from co 2 and suffered skin discoloration from unidentified components

volcanology history and myths of the lake albano maar colli albani volcano italy abstract the polygenetic albano maar is the most recent centre of the colli albani volcano located just few kilometres to the south east of roma presently the maar hosts a 167 5 m deep crater lake the deepest in europe the maar is to be considered quiescent as phreatic activity is documented throughout the holocene this paper illustrates the close relationships between the activity of the maar and the history of settlement in the roman region as recorded in the geology archaeology history and legends of the area severe fluctuations of the groundwater table and catastrophic overflows of the lake albano from the maar rim had occurred prior to and after the early prehistoric settlements dated in the maar area at the eneolithic times ca iii millennium b c repeated lahars occurred along the northwestern slope of the maar filling in the paleodrainage network and forming a vast plain paleohydraulic analyses on fluvial and lahar deposits originated from the holocene phreatic activity of the albano maar indicate sediment water flows in excess of hundreds of cubic metres per second absolute age determinations of the paleosoil underlying one of the most recent deposits of the lahar succession at 5800 100 yr b p 14 c cal are in perfect agreement with the age of the overlying eneolithic age settlements the last catastrophic overflow is described in the roman literature as a consequence of the anger of poseidon against the romans in 398 b c for their war against the etruscans in 394 b c the romans decided to prevent the repetition of such events by the excavation through the maar crater wall of a 1 5 km long drain tunnel which is still operational keeping the lake 70 m below the lowest point of the maar rim this tunnel drain may be regarded as the first prevention device for volcanic hazard in history and shows an unprecedented development of the engineering technology under the pressure of hazard perception the surprising and still largely unknown results of this study are very important to redefine the hazard of the roman region

origin of the northern atlantic s heinrich events as first noted by heinrich 1988 glacial age sediments in the eastern part of the northern atlantic contain layers with unusually high ratios of ice rafted lithic fragments to foraminifera shells he estimated that these layers are spaced at intervals of roughly 10 000 years in this paper we present detailed information documenting the existence of the upper five of these layers in odp core 609 from 50 n and 24 w their ages are respectively 15 000 radiocarbon years 20 000 radiocarbon years 27 000 radiocarbon years about 40 000 years and about 50 000 years we also note that the high lithic fragment to foram ratio is the result of a near absence of shells in these layers although we are not of one mind regarding the origin of these layers we lean toward an explanation that the heinrich layers are debris released during the melting of massive influxes of icebergs into the northern atlantic these sudden inputs may be the result of surges along the eastern margin of the laurentide ice sheet

natural hazards extreme events and mountain topography the hazard of any natural process can be expressed as a function of its magnitude and the annual probability of its occurrence in a particular region here we expand on the hypothesis that natural hazards have size frequency relationships that in parts resemble inverse power laws we illustrate that these trends apply to extremely large events such as mega landslides huge volcanic debris avalanches and outburst flows from failures of natural dams we review quantitative evidence that supports the important contribution of extreme events to landscape development in mountains throughout the world and propose that their common underreporting in the quaternary record may lead to substantial underestimates of mean process rates we find that magnitude frequency relationships provide a link between quaternary science and natural hazard research with a degree of synergism and societal importance that neither discipline alone can deliver quaternary geomorphology stratigraphy and geochronology allow the reconstruction of times magnitudes and frequencies of extreme events whereas natural hazard research raises public awareness of the importance of reconstructing events that have not happened historically but have the potential to cause extreme destruction and loss of life in the future

the role of ocean atmosphere reorganizations in glacial cycles abstract a case is made that glacial to interglacial transitions involve major reorganizations of the ocean atmosphere system such reorganizations constitute jumps between stable modes of operation which cause changes in the greenhouse gas content and albedo of the atmosphere only in this way can the rapidity of glacial terminations the hemispheric synchroneity and symmetry of mountain glaciation and the large polar air temperature and dustiness variations be accounted for if these reorganizations are driven in some fashion by orbitally induced seasonal insolation changes then the connection between insolation and climate is most likely through impacts of fresh water transport on the ocean s salinity distribution

surface water temperature salinity and density changes in the northeast atlantic during the last 45 000 years heinrich events deep water formation and climatic rebounds we developed a new method to calculate sea surface salinities sss and densities ssd from planktonic foraminiferal 18o and sea surface temperatures sst as determined from planktonic foraminiferal species abundances sst sss and ssd records were calculated for the last 45 000 years for biogeochemical oceanic flux study bofs cores 5k and 8k recovered from the northeast atlantic the strongest feature is the dramatic drop in all three parameters during the heinrich ice rafting events we modelled the possibility of deepwater formation in die northeast atlantic from the ssd records by assuming that the surface waters at our sites cooled as they flowed further north comparison with modelled north atlantic deepwater densities indicates that there could have been periods of deepwater formation between 45 000 and 30 000 14c years b p interrupted by iceberg meltwater input of heinrich event 3 and 4 at 27 000 and 38 000 14c years b p and during the holocene no amount of cooling in the northeast atlantic between 30 000 and 13 000 years could cause deep water to form because of the low salinities resulting from the high meltwater inputs from icebergs our records indicate that after each heinrich event there were periods of climatic rebound with milder conditions persisting for up to 2000 years as indicated by the presence of warmer and more saline water masses after these warm periods conditions returned to average glacial levels these short term cold and warm episodes in the northeast atlantic are superimposed on the general trend towards colder conditions of the last glacial maximum lgm heinrich event 1 appears to be unique as it occurs as insolation rose and was coeval with the initial melting of the fennoscandian ice sheet we propose that meltwater input of heinrich event 1 significantly reduced north atlantic deep water formation reducing the heat exchange between the low and high latitudes thus delaying deglaciation by about 1500 radiocarbon years 2000 calendar years

origin and consequences of cyclic ice rafting in the northeast atlantic ocean during the past 130 000 years deep sea sediment cores recovered from the northeast atlantic ocean were examined in order to elucidate the influence of the earth s orbital parameters on major ice rafting analyses of coarse grained ice rafted debris and planktonic foraminifers revealed a strong reaction to the precession signal since 130 000 yr b p dropstone layers have been deposited each half period of a precessional cycle 11 000 1000 yr ice rafting occurs during times of winter minimum summer maximum insolation and summer minimum winter maximum insolation in the first case high summer insolation forces meltwater discharge from the ice sheets into the polar seas which subsequently enhances formation of sea ice during the winter in the second case growth of continental ice enhances iceberg production which also leads to a salinity reduction of surface seawater both situations result in a southward penetration of polar water thus the marine record of dropstones documents ice rafting not only during weichselian stades but also during cold events within interstades the regularity of ice rafting yields a useful framework to calibrate and elucidate climatic changes not only in the region of the north atlantic ocean but also in remote areas such as the pacific ocean and the antarctic

isotope stratigraphy sedimentation rates deep circulation and carbonate events in the labrador sea during the last 200 ka high resolution stable isotope and accelerator mass spectrometry 14c measurements in 25 box and piston cores from the labrador sea allow the reconstruction of major paleoceanographical changes during the last 200 ka in this basin and also document the links between the interior of the laurentide ice sheet and the north atlantic ocean during this interval two deep circulation regimes are indicated by contrasting sedimentation rates on the slopes i the modern situation is characterized by a gyre of the north atlantic deep water nadw components into the basin which is responsible for the high energy western boundary undercurrent this regime also prevailed during the former true interglacials and possibly during shorter warm intervals e g bolling allerod ii a more frequent nadw free situation during glacial and interstadial intervals is marked by the presence of a vertically homogeneous water mass in the basin sedimentological records also indicate that carbonate events i e pulses of

evidence for changes in the north atlantic deep water linked to meltwater surges during the heinrich events abstract deep sea sediment records from north atlantic cores 40 n 55 n provide evidence of several massive iceberg discharges known as heinrich events during the last glacial period high resolution benthic 18 o and 13 c records from north atlantic sediment cores were used to monitor the impact of heinrich events on thermohaline circulation and to estimate the sensitivity of deep oceanic circulation to changes in freshwater input to the north atlantic surface waters our data indicate that major rearrangements of deep water masses were directly associated with these massive iceberg discharges to trace in detail the deep water conditions in the north atlantic benthic 13 c values in several cores were used to generate time slices before during and after heinrich event 4 dated at 35 ka bp although north atlantic deep water continued to form during the oxygen isotope stage 3 at 37 ka bp deep circulation was characterized by an increased incursion of deep waters of southern origin which reduced the 13 c composition of north atlantic deep waters particularly in the eastern atlantic basin north atlantic deep water production was reduced during heinrich layer 4 hl4 at 35 ka bp synchronously with the changes in the surface water hydrology deep convection processes may have occurred in areas not affected by the salinity decrease soon after hl4 33 ka bp the 13 c distribution was similar to that before the event similarly a rapid return to initial 13 c values was observed at the end of the most clearly defined heinrich events hl5 hl4 and hl1 comparison between deep circulation patterns corresponding to hl4 the last glacial maximum and heinrich event 1 indicates that each of these periods was characterized by a different circulation state associated with changes in convection sites

binge purge oscillations of the laurentide ice sheet as a cause of the north atlantic s heinrich events ice rafted debris in sediment cores from the north atlantic suggests that the laurentide ice sheet lis periodically disgorged icebergs in brief but violent episodes which occurred approximately every 7 000 years here i propose that heinrich events i e what these episodes are called were caused by free oscillations in the flow of the laurentide ice sheet which arose because the floor of hudson bay and hudson strait is covered with soft unconsolidated sediment that forms a slippery lubricant when thawed the proposed heinrich event cycle has two phases the growth phase occurs when the sediment is frozen and the lis is stranded immobile on a rigid bed the volume of the lis slowly grows during this phase at a rate dictated by snow accumulation the purge phase occurs when the basal sediment thaws and a basally lubricated discharge pathway i e an ice stream such as those which occur in west antarctica today developes through hudson strait the volume of the lis rapidly equilibrates to the reduced basal friction during this phase by dumping icebergs into the labrador sea the periodicity t k sl2g 2 7000 years of the proposed heinrich event cycle is a function of the thermal conductivity and diffusivity of ice k and respectively the atmospheric sea level temperature sl in degrees celsius and the excess geothermal heat flux defined by g g k where is the atmospheric lapse rate and g is the geothermal heat flux agreement between the predicted t and the apparent periodicity implied by the marine record is the main virtue of the free oscillation mechanism i propose an alternative mechanism in which heinrich events are forced by periodic variations in external climate is implausible because periodic atmospheric temperature perturbations are strongly attenuated with depth in an ice sheet

a new greenland deep ice core the polar ice sheets are rich sources of information on past atmospheric conditions including paleoclimates a new deep ice core has been drilled in south greenland comparison of the oxygen isotopic profile with that from camp century and with a deep sea foraminifera record indicates that the new core reaches back to about 90 000 years before present in a continuous sequence the details in the wisconsin part of the ice core records seem to be climatically significant and the general trends reveal all of the relevant emiliani stages recorded in deep sea cores the redated camp century record suggests a dramatic termination of the eem sangamon interglacial

volcanic impediments in the progressive development of pre columbian civilizations in the ecuadorian andes abstract archaeological investigations in ecuador have proposed that there appear to be hiatus or anomalous jumps in the progressive development of pre columbian indigenous cultures based upon the fact that their ceramics and tools demonstrate abrupt advances in their sophistication at several horizons in the soil profile because some of these horizons are clearly associated with volcanic ash layers archaeologists have sought a causal relation with volcanism that is the eruptive events or their products severely interfered with the early inhabitants resulting in their abandonment of certain areas geological studies of the young volcanoes in the ecuadorian andes carried out during the past two decades now allow us to make a more thorough evaluation of the role of volcanism during the holocene this contribution briefly describes the principal holocene volcanic events and the distribution of the corresponding eruptive products found along the interandean valley from southern colombia to central ecuador only those events that were sufficiently large that they could have had a detrimental effect on the valley s early residents are discussed dacitic and rhyolitic ash flows as well as numerous debris flows lahars have occurred frequently and their deposits cover many valleys and floodplains where early inhabitants probably settled the enormous chillos valley lahar associated with the 4500 ybp eruption of cotopaxi volcano buried soils containing ceramics of the early formative period however the greatest impact upon mankind was probably not these short lived violent events but rather the burying of settlements and agricultural fields by ash fallout the effect of which may have lasted hundreds of years ash fall layers are observed in pre columbian cultural horizons in the soil profile occurring in the interandean valley the lower flanks of the andes and along ecuador s pacific coast the oldest corresponding to the 5800 ybp eruption of cotopaxi this brief study provides the archaeologist with a more detailed listing of notable volcanic events that may guide future investigations of past cultures

provinciality of ice rafting in the north atlantic application of 40ar 39ar dating of individual ice rafted hornblende grains the history of the northern hemisphere ice sheets is an important aspect of the paleoclimate system the layered record of ice rafted detritus ird and other climate indicators preserved in deep sea sediment cores provides the potential to unravel the sequences of events surrounding important intervals during the last glacial cycle the work presented here is a first step in the goal to characterize the composition of glacially derived detritus in proximal locations near the laurentide greenland and scandinavian ice sheets the intent of this paper is to highlight the potential for using provenance studies of ird in marine sediments in particular 40 ar 39 ar ages of hornblende grains in this case to trace the history of ice sheets in the past published work on land and at the glacial marine margins has mapped the margins of important ice sheets including the locations where glacial ice extended to the shelf slope break at these shelf slope break locations large glacial marine fans termed trough mouth fans tmf are known to occur in about 25 locations around the north atlantic nordic arctic oceans by characterizing the sediment sources in these tmfs the major ird components for deposition in deep sea sediment cores are documented although there is substantial overlapin the geological histories of the continental sources around the north atlantic there are also some systematic variations that will allow distinction of different sources realization of the full potential awaits characterizing the sources with multiple tracers as well as sedimentological studies and documenting the geographic pattern of dispersal in marine sediments within small time windows r 2002 published by elsevier science ltd

biogenic carbonate and ice rafted debris heinrich layer accumulation in deep sea sediments from a northeast atlantic piston core abstract biogenic carbonate mass accumulation rates show distinct quaternary glacial interglacial changes in a mid latitude northeast atlantic deep sea core during the last 208 kyr these were generally higher during interglacials averaging 2 2 g cm 2 kyr than during glacial periods with a maximum average of 1 2 g cm 2 kyr intervals containing high ice rafted debris have very low biogenic carbonate accumulation rates paleo primary productivity estimates based on biogenic carbonate accumulation rates are generally higher during interglacials averaging 80 gc m 2 yr than during glacials which average 49 gc m 2 yr maximum estimate short intervals with possibly reduced primary productivity correspond to heinrich layers which are the result of pulses of massive iceberg production and rapid melting in the north atlantic we identified thirteen heinrich layers in isotopic stages 7 to 2 they have calendar ages of about 201 189 182 183 164 167 146 149 142 128 131 64 67 52 54 40 43 29 31 21 and 15 kyr these heinrich layers contain large amounts of ice rafted debris including detrital carbonate low amounts of coccoliths and planktic foraminifera mainly neogloboquadrina pachyderma sinistral the upper five heinrich layers are almost barren of coccoliths and the fourth layer is also free of foraminifera the virtual absence of coccoliths is interpreted to reflect reduced coccolithophorid productivity in the photic zone due to low salinity of surface waters and to blockage of light by ice and suspended materials shed off by melting icebergs considering the limited use of other proxies such as organic carbon diatom and benthic foraminifera due to their very low content abundance in the sediments biogenic carbonate mass accumulation rates offer a workable paleo primary productivity proxy in open ocean sediments of the carbonate dominated northeast atlantic

volcanism in aboriginal australian oral traditions ethnographic evidence from the newer volcanics province abstract this article collects and presents nineteenth century ethnographic evidence from the newer volcanics province of australia and explores how volcanism was recorded and understood in aboriginal oral traditions it investigates whether aboriginal australian oral traditions can be understood as persistent eyewitness accounts of volcanic eruptions in the newer volcanics province how and what kind of geological and volcanological knowledge was embedded within aboriginal australian oral traditions and considers what value the ethnographic evidence has for understanding both the socio cultural and geological histories of the newer volcanics province

deep circulation change linked to heinrich event 1 and younger dryas in a middepth north atlantic core a core from the mid atlantic ridge at 43 5 n and 3 km water depth shows distinct evidence of the deglacial events known as heinrich event 1 probably the marine equivalent of oldest dryas cooling in europe and the younger dryas the heinrich event dated at three levels to between 14 3 and 15 0 ka is marked by a minimum in foraminifera per gram by maxima in rates of sedimentation ice rafted debris per gram and relative abundance of n pachyderma s and by a 18o minimum in planktonic foraminifera the younger dryas event is marked by peak abundance of n pachyderma s and a planktonic 18o maximum benthic foraminiferal 13c reaches minimum values during both the heinrich event and the younger dryas our data indicate pronounced changes in surface water properties were coupled with reduced production of north atlantic deep water at each of these times

simmax a modern analog technique to deduce atlantic sea surface temperatures from planktonic foraminifera in deep sea sediments we present a data set of 738 planktonic foraminiferal species counts from sediment surface samples of the eastern north atlantic and the south atlantic between 87 n and 40 s 35 e and 60 w including published climate long range investigation mapping and prediction climap data these species counts are linked to levitus s 1982 modern water temperature data for the four caloric seasons four depth ranges 0 30 50 and 75 m and the combined means of those depth ranges the relation between planktonic foraminiferal assemblages and sea surface temperature sst data is estimated using the newly developed simmax technique which is an acronym for a modern analog technique mat with a similarity index based on 1 the scalar product of the normalized faunal percentages and 2 a weighting procedure of the modern analog s ssts according to the inverse geographical distances of the most similar samples compared to the classical climap transfer technique and conventional mat techniques simmax provides a more confident reconstruction of paleo ssts correlation coefficient is 0 994 for the caloric winter and 0 993 for caloric summer the standard deviation of the residuals is 0 90 c for caloric winter and 0 96 c for caloric summer at 0 m water depth the sst estimates reach optimum stability standard deviation of the residuals is 0 88 c at the average 0 to 75 m water depth our extensive database provides sst estimates over a range of 1 4 to 27 2 c for caloric winter and 0 4 to 28 6 c for caloric summer allowing sst estimates which are especially valuable for the high latitude atlantic during glacial times an electronic supplement of this material may be obtained on adiskette or anonymous ftp from kosmos agu org login toagu s ftp account using anonymous as the username and guestas the password go to the right directory by typing cd append typels to see what files are available type get and the name of the file toget it finally type exit to leave the system paper 95pa01743 simmax a modern analog technique to deduce atlantic sea surfacetemperatures from planktonic foraminifera in deep sea sediments uwepflaumann josette duprat claude pujol and laurent d labeyrie diskette may be ordered from american geophysical union 2000florida avenue n w washington dc 20009 payment mustaccompany order

the gas cloud of lake nyos cameroon 1986 results of the italian technical mission abstract on august 21 1986 a gas cloud issued from lake nyos in cameroon killed over 1700 people an italian technical mission reached the area seven days later and obtained the first field evidences of the catastrophe on the basis of observations and measurements in the field and of samples collected the origin of the gas outburst is attributed to a phreatic explosion from beneath the bed of the lake this interpretation appears to fit well the observed and reported phenomena and seems perfectly consistent with the geological geothermal conditions of the area

oceanic evidence for coherent fluctuations in fennoscandian and laurentide ice sheets on millennium timescales proxy temperature records from greenland ice cores1 2 and north atlantic sediment cores3 have provided evidence for a high degree of climate instability during the last glacial period much of this variability seems to be linked with the dynamics of the laurentide ice sheet that covered north america at this time3 which dis charged iceberg flotillas into the north atlantic that are now recorded in sediment cores as heinrich events4 how if at all this variability was manifested on the other side of the atlantic in the nordic seas and the ice sheets of northwest europe and scandinavia has been unclear here we present sediment micro fossil and oxygen isotope data from a sediment core in the norweg ian sea which reveal cooling events and iceberg discharges analogous to heinrich events we show that these climate fluctua tions in the norwegian sea were in phase or were phase locked with air temperatures over greenland suggesting that the rapid changes in heat fluxes in the north atlantic recorded in previous records3 were felt in this high latitude region the iceberg dis charges in our record seem to have come from the fennoscandian ice sheet implying that this and the laurentide ice sheets fluctu ated coherently on timescales shorter than those of milankovitch orbital cycles

the sedimentary record of drifting ice early wisconsin sunnybrook deposit in an ancestral ice dammed lake ontario canada abstract outcrops of pebbly mud diamict at scarborough in southern ontario canada the so called sunnybrook till are associated with the earliest incursion of the laurentide ice sheet lis into mid continent north america some 45 000 years ago the sunnybrook is a blanket like deposit containing deepwater ostracodes and occurs conformably within a thick 100 m succession of deltaic and glaciolacustrine facies that record water depth changes in a large proglacial lake contextual evidence associated facies sedimentary structures deposit geometry and landforms indicates a low energy depositional setting in an ice dammed ancestral lake ontario in which scouring by floating ice masses was an important process u shaped iceberg cut scours with lateral berms up to 7 m deep occur on the upper surface of the sunnybrook and are underlain by sub scour structures that extend several meters below the scour base ice rafted concentrations of clasts clast layers grooved surfaces formed by floating ice glissading over a muddy lake floor soft sediment striations and melanges of sand and mud mixed by grounding ice keels ice keel turbates are present and are all well known from modern cold environments the wider significance of this depositional model is that the lis margin lay east of scarborough and did not overrun southern ontario this finding is in agreement with recent data from the erie basin of canada ohio and indiana where deposits formerly correlated with the sunnybrook and thus implying an extensive early wisconsin ice sheet are now regarded as illinoian a speculative hypothesis is proposed that relates deposition of the sunnybrook and two younger deposits of similar sedimentology to surge like instabilities of the southern lis margin

emplacement of the most recent lava flows on hualālai volcano hawai i a detailed field and petrologic study of the ca 1800 a d flows at hual lai volcano documents at least two eruptive episodes the hu ehu e flow field ending in 1801 and the ka p lehu flow several decades earlier the morphology and stratigraphy of the ka p lehu flow require an emplacement duration of several days to weeks based on a comparison with recent eruptive activity at mauna loa volcano the eruption cannot have occurred at the anomalously high rate 104 105 m3 s proposed by previous workers the hummocky flow surface of the later phase of the hu ehu e eruption suggests a duration of months based on a comparison with recent eruptive activity at k lauea volcano although none of the ca 1800 flows show evidence for extraordinarily fast emplacement or unusual fluid rheologies both flows show unusual features the abundant xenoliths for which the ka p lehu flow is famous were transported in numerous episodes of deposition and remobilization during which they eroded the channel systems through which they traveled lava transport in proximal and medial regions of both flow fields was probably through lava tubes as evidenced by preserved tubes and by the prevalence of p hoehoe lined channels that require thermally efficient transport of lava over great distances both flows also show abundant evidence for re occupation of older cones and lava tubes a characteristic that may typify infrequent eruptions of older volcanic systems although lava flows from hual lai volcano do not show anomalous eruptive behavior they pose a substantial hazard for coastal communities of kona

variable effects of cinder cone eruptions on prehistoric agrarian human populations in the american southwest abstract two 900 bp cinder cone eruptions in the american southwest affected prehistoric human populations in different ways mostly because of differences in the eruption styles and area affected primary pre eruption cultural factors that may have led to successful adaptation to the eruptions include decision making at the family or household level low investment in site structures dispersion of agricultural sites in varied environments and settlement spread over a large area so that those who were less affected could shelter and feed evacuees sunset crater near flagstaff arizona produced about 8 km 2 lava flow fields and a 2300 km 2 tephra blanket in an area that had been settled by prehistoric groups for at least 1000 years local subsistence relied on agriculture primarily maize and 30 cm tephra cover rendered 265 km 2 of prime land unfarmable this area was apparently abandoned for at least several generations a 500 km 2 area was probably marked by collapsed roofs and other structural damage from the fallout if the eruption occurred during the agricultural season the fallout would also have significantly damaged crops the eruption did have some benefits to local groups because lower elevation land which had previously been too dry to farm became agriculturally productive due to 3 8 cm of tephra mulch and some temporary soil nutrient improvements this previously uninhabited land became the site of significant year round settlement and farming eventually containing some of the largest pueblo structures ever built in the region new agricultural techniques were developed to manage the fallout mulch the eruption also affected ceramic production and trading patterns and volcano related ritual behavior the production of maize impressed lava spatter agglutinate was initiated little springs volcano about 200 km northwest of sunset crater is a small spatter rampart around a series of vents that produced about 5 km 2 of lava flow fields about 1 km 2 of land severely affected by ballistic fall and no significant tephra fall the small area affected resulted in much less disruption of human activities than at sunset crater farming was still possible right up to the edge of the lava flows which became attractive sites for settlements most sites along the lava flows have habitation and storage structures at the base of the flow and a series of small apparently little used structures on the blocky lava flow above these lava surface structures may have been defensive in nature in addition trails were constructed on the blocky lava flow surface these trails whose access points are difficult to recognize from below appear to have been used for rapid movement across the flows and may also have been defensive in nature spatter agglutinate blocks containing ceramic sherds within them similar to the maize impressed spatter agglutinate at sunset crater were made at little springs and carried to a nearby habitation site in arid and semiarid lands such as northern arizona tephra fall is a mixed blessing thick cinder blankets 20 30 cm render land uninhabitable but thinner 3 8 cm deposits can serve to conserve soil moisture regulate soil temperature thus lengthening the growing season and by lowering soil ph provide a temporary decades to a century or two increase in available phosphorus an important nutrient for growth the mulch opened up new lands for settlement but likely only lasted for a century or two before reworking reduced its effects

crystal chemistry of trioctahedral micas in the top sequences of the colli albani volcano roman region central italy abstract trioctahedral mica crystals are frequently found in the volcanoclastic products emplaced during the final stages of the activity of the colli albani volcano roman region central italy in the youngest phreatomagmatic deposits mica is found either as a minor mineral phase in holocrystalline ejecta scoriae and coherent pyroclastics or as loose phenocryst in incoherent pyroclastics based on optical and electron microscope investigations as well as crystal chemical and structural data the micas selected for this study were divided into two groups the first one encompassing brownish fe rich crystals type a phlogopites hereafter referred as t a with 0 68 from a petrological point of view the textural and chemical variations of t a phlogopites are compatible with fractional crystallization processes taking place within the magma chamber t b phlogopites show evidence of a ti oxy substitution mechanism thus suggesting high fo2 conditions textural and paragenetic features observed in t b phlogopite bearing rock samples indicate a genesis by thermal metamorphism of a siliceous dolomitic limestone with the input of a variable amount of a potassic magma possibly the same from which the t a phlogopites formed with the exception of one sample for which a different parental magma is suggested indeed there is an almost continuous spectrum of crystal chemical and structural parameters starting from t b and evolving towards t a phlogopites the t a phlogopites displays complex apparently meaningless relationships in their crystal chemical parameters thus indicating interplay of several substitution mechanisms they possibly formed in polybaric conditions since their cell volumes differ but the total size of the cations hosted in the octahedral sheet is the same

western north atlantic evidence for millennial scale changes in ocean circulation and climate two late quaternary series of high resolution percent carbonate data from western north atlantic sediment drifts bermuda rise and bahama outer ridge show millennial scale oscillations superimposed on the familiar longer period oscillations of orbital origin the dominant high frequency oscillation in these records has a quasi period of about 4000 years these percent caco3 changes most likely result from the influence of climate change on the flux of terrigenous material from eastern canada the resuspension of continental margin sediment by deep eddy kinetic energy and carbonate dissolution sediment is transported to the bermuda rise by deep recirculating gyres and to the bahama outer ridge by the deep western boundary current system stable isotope results on foraminifera across several of these oscillations from interstadial climate conditions and from a glacial inception display variability similar to that of percent caco3 oxygen isotope ratios of planktonic foraminifera suggest large variations in near surface temperature and or salinity and carbon isotope ratios of benthic foraminifera indicate that there were significant oscillations in the flux of north atlantic deep water nadw these data support models which couple surface ocean conditions in the north atlantic production of nadw north atlantic heat flux and evidence for temperature oscillations in ice cores

the role of the north atlantic drift in the millennial timescale glacial climate fluctuations abstract the greenland ice core records show that the overall cold climate of the last glacial period was repeatedly interrupted by short rapid warmings the events known as dansgaard oeschger d o events are strongly imprinted in the north atlantic marine records suggesting that they were linked to north atlantic circulation changes however the causes of the d o events are poorly understood and they represent one of the most intriguing puzzles of the last glacial period in order to investigate a possible mechanism we have studied variations in the distribution of benthic and planktonic foraminifera oxygen isotopes and ice rafted debris during the last glacial period in eight cores from the north atlantic and the nordic seas taken at mid depth from 853 to 1760 m the parameters indicate in agreement with previous studies that the circulation system during the interstadials resembled the present system atlantic surface water flowed north into the nordic seas where most of it sank through convection and as cold deep water flowed back into the north atlantic during the stadials a halocline was established in the nordic seas and in the northernmost part of the north atlantic and the outflow from the nordic seas stopped however below the cold light surface layer the relatively warm water of the north atlantic drift continued to flow across the north atlantic and into the nordic seas here warming up the deep water masses we suggest that the warm water gradually made the water column unstable the pivotal abrupt climate warmings were caused by sudden upwelling of the deep warm water masses causing overturning of the entire water column and onset of convection

welcoming a monster to the world myths oral tradition and modern societal response to volcanic disasters abstract volcanic eruptions can overwhelm all senses of observers in their violence spectacle and sheer incredibility when an eruption is catastrophic or unexpected neither individuals nor communities can easily assimilate the event into their world view psychological studies of disaster aftermaths have shown that trauma can shake the very foundations of a person s faith and trigger a search supernatural religious or scientific for answers for this reason the ability to rapidly comprehend a traumatic event by accepting the catastrophe as part the observer s world represents an important component of community resilience to natural hazards a relationship with the event may be constructed by adapting existing cosmological ancestral or scientific frameworks as well as through creative and artistic expression in non literate societies communal perceptions of an event may be transformed into stories that offer myth like explanations as these stories make their way into oral traditions they often undergo major changes to allow transmission through generations and in some cases to serve political or religious purposes disaster responses in literate societies are no different except that they are more easily recorded and therefore are less prone to change over time here we explore ways in which the language imagery and metaphor used to describe volcanic events may link disparate societies both present and past in their search for understanding of volcanic catastrophes responses to modern eruptions 1980 mount st helens usa and 1995 present soufriere hills montserrat provide a baseline for examining the progression to older historic events that have already developed oral traditions 1886 tarawera new zealand and finally to oral traditions many hundreds of years old in both the pacific northwest us and new zealand nz we see that repeated volcanism over many generations produces rich webs of cosmology and history surrounding volcanoes nz maori have incorporated volcanoes into the lineage of tribes and individuals thus good and bad outcomes from volcanism are part of long term cycles of reciprocity and equilibrium that link modern maori to their ancestors in both regions cosmologies and mythologies not only document the attempts of past cultures to recover from the impacts of volcanic disasters but also provide a means by which following generations can understand contextualize and therefore recover from future volcanic catastrophes we further suggest that such local traditions can provide a valuable community education tool as well as an important means of aiding the psychosocial recovery of individuals and communities after volcanic disasters

patterns of ice rafted detritus in the glacial north atlantic 40 55 n the observation by heinrich 1988 that during the last glacial period much of the input of ice rafted detritus to the north atlantic sediments may have occurred as a succession of catastrophic events rekindled interest on the history of the northern ice sheets over the last glacial period in this paper we present a rapid method to study the distribution of these events both in space and time using whole core low field magnetic susceptibility we report on approximately 20 cores covering the last 150 to 250 kyr well defined patterns of ice rafted detritus appear during periods of large continental ice sheet extent although these are not always associated within their maxima most of the events may be traced across the north atlantic ocean for the six most recent heinrich layers hl two distinct patterns exist hl1 hl2 hl4 hl5 are distributed along the northern boundary of the glacial polar front over most of the north atlantic between 40 and 50 n hl3 is more restricted to the central and eastern part of the northern atlantic the nd sr isotopic composition of the material constituting different heinrich events indicates the different provenance of the two patterns hl3 has a typical scandinavia arctic icelandic young crust signature and the others have a large component of northern quebec and northern west greenland old crust material these isotopic results obtained on core su 9008 from the north american basin are in agreement with the study by jantschik and huon 1992 who used k ar dating of silt and clay size fractions of an eastern basin core me 68 89 these data confirm the large spatial scale of these events and the enormous amount of ice rafted detritus they represent

physical properties of reykjanes ridge sediments and their linkage to high resolution greenland ice sheet project 2 ice core data five gravity cores taken from the reykjanes ridge have been used to establish a link between sediment physical properties and atmospheric records documented by 18o variations in greenland ice cores over the last 45 000 calendar years marine gamma ray attenuation porosity evaluator density and magnetic susceptibility variations could be linked with the ice core dansgaard oeschger and bond cycles this is supported by ice rafted detritus ird grain size the quartz feldspar ratio and carbonate isotopic and foraminiferal records the covariation of the sediment physical properties and 18o in greenland ice indicates a coupling of atmospheric temperature and paleocirculation variations gradual reduced bottom currents iceland scotland overflow water and enhanced iceberg discharges have been reconstructed for cold atmospheric periods relative to interstadial times in the study area the magnetic susceptibility signal is not related to the ice rafted detritus input but most probably reflects the variations of the iceland scotland overflow water intensity transporting titanomagnetite into the reykjanes ridge region

modeling the distribution and seasonality of neogloboquadrina pachyderma in the north atlantic ocean during heinrich stadial 1

anatomy of a dansgaard oeschger warming transition high resolution analysis of the north greenland ice core project ice core large and abrupt temperature oscillations during the last glacial period known as dansgaard oeschger do events are clearly observed in the greenland ice core record here we present a new high resolution chemical 2 mm and stable isotope 20 mm record from the north greenland ice core project ngrip ice core at the onset of one of the most prominent do events of the last glacial do 8 observed 38 000 years ago the unique subannual resolution ngrip record provides a true sequence of change during a do warming with detailed annual layer counting of very high depth resolution geochemical measurements used to determine the exact duration of the transition the continental ions indicative of long range atmospheric loading and dustiness from east asia are the first to change followed by the snow accumulation the moisture source conditions and finally the atmospheric temperature in greenland the sequence of events shows that atmospheric and oceanic source and circulation changes preceded the do warming by several years

tephras and new zealand archaeology establishing an accurate date for earliest polynesian settlement in new zealand is essential for understanding patterns of settlement and associated enviromental impacts and the processes and rates of cultural change in eastern polynesia tephra deposits from five volcanic centres together with exotic sea rafted pumice provide isochronous constraints on the timing of earliest settlement and human impacts in northern new zealand a local basaltic tephra from rangitoto island auckland and locally distributed andesitic tephras from egmont volcano directly date human occupation toc ad 1400 1450 distal andesitic tephras tufa trig formation from mt ruapehu tongariro volcanic centre help constrain the timing of earliest anthropogenic deforestation signals in hawke s bay sea rafted loisels pumice s although of uncertain stratigraphic reliability in places overlies cultural remains that can be no younger thanc ad 1350 along the east coast north island the regionally extensive rhyolitic kaharoa tephra which erupted from okataina volcano between c ad 1300 1390 is the critical settlement layer datum for dating prehistory in the north island no human artefacts are recorded beneath it and the earliest inferred environmental impacts by humans are dated to c ad 1280 just prior to its deposition this maximum date matches the earliest radiocarbon dates derived for both settlement and human impacts from archaeological and natural sites c ad 1250 and implies that the onset of deforestation was essentially contemporaneous with initial settlement the widespread rhyolitic taupo tephra which erupted from taupo volcanoc ad 200 provides an isochronous benchmark well before earliest settlement the tephra may coincide approximately with a putative earlier transient contact in new zealand based on pacific rat bone rattus exulans dates more precise calendrical dates on the tephras via dendrochronology or ice core records or other dating methods would help refine assessment of the timing of earliest settlement while extending the distributional range of critical tephra layers through application of crypto tephra analysis could lead to a greater understanding of settlement patterns

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

masaya the mouth of hell nicaragua volcanological interpretation of the myths legends and anecdotes article i nfo nicaragua s conquest started only 30years after christopher columbus arrived to america in 1492 at that moment the masaya and momotombo volcanoes were erupting simultaneously the former was the first permanent lava lake observed by europeans and this produced a strong impression and interest in it for more thanacenturytherewasgreatcontroversyoverthenatureofthisphenomenon somepeoplebelievedthatitwas

living near volcanoes scoping the gaps between the local community and volcanic experts in southern chile abstract human societies have always inhabited volcanic zones but only recently scientists and decision makers have turned the attention to volcanic risk prevention and reduction despite a growing consensus about the importance of engaging with nearby populations in practice there is little dialogue with them regarding volcanic threats and opportunities we study the experiences impacts and concerns of an indigenous community inhabiting in between two major volcanic systems carran los venados and puyehue cordon caulle regarding past and recent eruptions results show a longstanding cultural and economic interrelationship between people and volcanoes representing both benefits and barriers to development existing local traditional knowledge is necessary but not sufficient to meet people s needs for adequate understanding and forecasting despite community interest on volcanic science and risk reduction important communication and trust gaps with experts persist our findings suggest the importance for scientists to establish collaborative and participatory relationships with local communities and decision makers with the goal of not only reducing negative volcanic impacts and uncertainty but also taking advantage of the potential of volcanic environments to boost local sustainable livelihoods

the albano maar lake colli albani volcano italy recent volcanic activity and evidence of pre roman age catastrophic lahar events abstract the evaluation of volcanic hazard in the roman hinterland related to the quiescent colli albani volcano has recently been the subject of renewed attention and several interpretations by many authors however very little was known of the recent history of the volcano making such interpretations rather speculative the most recent activity of colli albani volcano originated from the albano polygenetic maar lake which erupted several phreatomagmatic units the most recent of which the peperino albano ignimbrite has been dated at around 25 ka an area of several square kilometers centered around albano lake is presently the site of shallow and frequent seismic activity and gaseous emission as well as hydrothermal activity and is therefore considered the most prone to geologic hazards this paper presents new stratigraphic and geomorphologic data as well as age determinations that allow rejuvenation of the most recent activity of the colli albani volcano and particularly the albano maar lake to the holocene this study allows for the first time to identify a potential hazard related to the albano maar lake withdrawal interpreted to be related to endogenous causes namely co 2 emission the main results of the study are 1 the peperino albano is not as is generally believed the last phreatomagmatic eruption from the colli albani volcano a previously unrecognized phreatomagmatic surge deposit has been identified overlying the paleosol at the top of the peperino albano and related lahar deposits 2 two lahar deposits separated by paleosols top the stratigraphic succession and are dispersed only to the nw corresponding to the lowest point of the maar rim indicating that catastrophic hydrologic events occurred at the albano lake in recent times rapid and substantial lake level variations and lake withdrawal are reported by roman historians and recorded by the stratigraphy of the albano lake lacustrine sediments 3 microfracturing related to seismic energy release is linked to sudden variation of co 2 flow and upwelling of hydrothermal fluids these occurrences across the lake are the likely causes that triggered during holocene several episodes of lake withdrawal rising the water table and probably triggering convective rollover of the lake water

the taylor dome antarctic 18o record and globally synchronous changes in climate abstract the 18 o 16 o profile of a 554 m long ice core through taylor dome antarctica shows the climate variability of the last glacial interglacial cycle in detail and extends at least another full cycle taylor dome shares the main features of the vostok record including the early climatic optimum with later cool phase of the last interglacial period in antarctica taylor dome 18 o fluctuations are more abrupt and larger than those at vostok and byrd station although still less pronounced than those of the greenland gisp2 and grip records the influence of the atlantic thermohaline circulation on regional ocean heat transport explains the partly north atlantic character of this antarctic record under full glacial climate marine isotope stage 4 late stage 3 and stage 2 this marine influence diminished and taylor dome became more like vostok varying degrees of marine influence produce climate heterogeneity within antarctica which may account for conflicting evidence regarding the relative phasing of northern and southern hemisphere climate change

centennial scale surface hydrology off portugal during marine isotope stage 3 insights from planktonic foraminiferal fauna variability 1 the marine isotopic stage 3 mis3 at ocean drilling program odp site 1060 gulf stream shows both sharp onset and end of interstadials the existence of very short lived warm events during stadials and points to differences in detail between the sea surface temperature sst record from the western north atlantic and the atmospheric temperature record inferred from 18o in greenland ice investigating mis3 and obtaining comparable data from other locations appears crucial the eastern atlantic provides well documented records of climate changes we have selected a core from off portugal and use it to examine dansgaard oeschger events d o at centennial scale resolution 139 years on average between two data points we have obtained a faunal data set for core md01 2444 37 n 10 w 2600 m water depth and use a group of species globigerina bulloides globigerinita glutinata as a proxy of upwelling intensity driven by trade winds intensity changes we tentatively relate the variation of this group to a north atlantic oscillation like phenomenon nao off portugal we observe that it resembles the rainfall index in the caribbean as recorded at odp site 1002 cariaco basin which traces the intertropical convergence zone itcz location through changes of terrigenous inputs the driest intervals itzc to the south at site 1002 correspond to intervals of increased upwelling in md01 2444 as well as the driest periods identified during stadials on similar cores in the area because the itzc to the south is consistent with an el nino southern oscillation enso situation our study suggests a positive correlation between enso like conditions and nao like conditions at a millennial timescale during interstadial intervals when increased wetness over cariaco is recorded itcz to the north and the upwelling in md01 2444 is decreased we see from both ssts and faunal tropical indicators that md01 2444 site is warm in addition interstadials are equally warm through each so called bond cycle this contrasts with the greenland ice core project grip record where interstadial peaks are successively cooler through each bond cycle this record confirms a link between tropical climate linked to itcz position and the climate of southern europe at millennial timescales in spite of showing a very good correlation with polar latitudes grip through 18o on globigerina bulloides in addition because the warmest ssts and the 18o on g bulloides are so remarkably different our work points to changes in seasonality as a strong control over the climatic pattern of the north atlantic area and the marked influence of winter conditions

the impact of the ischia porto tephra eruption italy on the greek colony of pithekoussai abstract the island of ischia is an active volcanic field whose activity dates back to more than 150 ka from neolithic times it experienced a complex history of human colonization and volcanic eruptions that destroyed settlements and drove away the population recent archaeological and volcanological research has demonstrated that humans have periodically had to face volcanic and related hazardous phenomena since at least the greek foundation of pithekoussai 8th century bc during the 5th century bc a telluric event is reported by the historian strabo to have caused the abandonment of a syracusan military outpost on the island in the volcanological literature the ischia porto tephra eruption has been identified as the most likely culprit the eruption formed a crater lake in the north eastern corner of the island and emplaced a poorly dispersed pyroclastic deposit composed of a sequence of magmatic and phreatomagmatic scoria and pumice fallout beds interlayered with minor pyroclastic density current deposits recent excavations furnished clear evidence of the impact of this eruption on a settlement located on s pietro hill to the east of ischia s harbour the archaeological finds include mounds of building materials pieces of decorative terracotta panels and a few terracotta antefix fragments the spatial distribution of the material found the presence of stacks of tiles and other building materials and the absence of any structural remains suggest that this was a building site for the construction of a temple as written sources confirm although the site and the military garrison were abandoned the colony survived

the climate in western europe during the last glacial interglacial cycle derived from pollen and insect remains using the pollen sequence of la grande pile xx france we review problems with the application of transfer functions in paleoclimatic reconstructions one of them is to find modern analogues for the herbaceous vegetation of the cold periods we propose a method to distinguish between steppes and tundra vegetations for which the moderns are only partial analogues of the glacial periods another method to solve these problems is based on constraining by insect remains the two methods provide coherent reconstructions the results are also compared with other paleodata there is a good correlation with the six cold heinrich events between 70 and 15 ka b p a cooling event during the eemian period marked by high percentages of taxas at about 125 ka b p needs still to be correlated with high resolution ocean and ice cores

a prehistoric lahar dammed lake and eruption of mount pinatubo described in a philippine aborigine legend the prehistoric eruptions of mount pinatubo have followed a cycle centuries of repose terminated by a caldera forming eruption with large pyroclastic flows a post eruption aftermath of rain triggered lahars in surrounding drainages and dome building that fills the caldera and then another long quiescent period during and after the eruptions lahars descending along volcano channels may block tributaries from watersheds beyond pinatubo generating natural lakes since the 1991 eruption the mapanuepe river valley in the southwestern sector of the volcano has been the site of a large lahar dammed lake geologic evidence indicates that similar lakes have occupied this site at least twice before an ayta legend collected decades before mount pinatubo was recognized as a volcano describes what is probably the younger of these lakes and the caldera forming eruption that destroyed it

multiprofile discharge estimation in the tidal reach of yangtze estuary abstractwith the advent of acoustic doppler current profiler adcp the velocity profile method or index velocity method based on a single profile or a fixed depth cell has been recommended for estimating discharge in tidal reaches however in large tidal reaches with a width of nearly 6 km and cross sectional variability of flow such as yangtze estuary these methods are not accurate enough for the discharge estimation therefore an improved method named the multiprofile method is proposed in this paper the method includes four main steps 1 calculating the cross sectional area a with stage data by considering the transverse slope 2 calculating the depth mean velocity u at each fixed adcp 3 establishing the u u model with the multiprofile us and estimating the cross sectional mean velocity u 4 estimating the final discharge through u multiplied by a the proposed method was tested at the xuliujing section of the yangtze estuary the result shows that the multiprofile method averagely imp

hawaiian oral tradition describes 400 years of volcanic activity at kīlauea article i nfo culturally significant oral tradition involving pele the hawaiian volcano deity and her youngest sister hi iaka may involve the two largest volcanic events to have taken place in hawai i since human settlement the roughly 60 year long ail au eruption during the 15th century and the following development of k lauea s caldera in 1823 rev william ellis and three others became the first europeans to visit k lauea s summit and were told stories about k lauea s activity that are consistent with the pele hi iaka account and extend the oral tradition through the 18th century recent geologic studies confirm the essence of the oral traditions and illustrate the potential value of examining other hawaiian chants and stories for more information about past volcanic activity in hawai i published by elsevier b v

northeast atlantic sea surface circulation during the past 30 10 14c kyr b p a study was made of three cores from the faeroe shetland gateway based on planktonic foraminifera oxygen isotopes accelerator mass spectrometry 14c dates magnetic susceptibility and counts of ice rafted debris ird the data covering the period 30 10 ka show that during the last glacial maximum the arctic front occupied a position close to the faeroes allowing a persisting inflow of atlantic surface water into the faeroe shetland channel the oceanographic environment during deposition of two ird layers is influenced by atlantic surface water masses during the lower ird layer with transport of icebergs from n nw polar surface water conditions prevailed only during deposition of the upper ird layer there is no indication of surface meltwater influence in the region during the deglaciation but there is a persistent influence of atlantic surface water masses in the region thus we conclude that during almost the entire period 30 10 ka the faeroe shetland channel was a gateway for transport of atlantic surface water toward the norwegian sea

volcanic tsunamis and prehistoric cultural transitions in cook inlet alaska abstract the 1883 eruption of augustine volcano produced a tsunami when a debris avalanche traveled into the waters of cook inlet older debris avalanches and coeval paleotsunami deposits from sites around cook inlet record several older volcanic tsunamis a debris avalanche into the sea on the west side of augustine island ca 450 years ago produced a wave that affected areas 17 m above high tide on augustine island a large volcanic tsunami was generated by a debris avalanche on the east side of augustine island ca 1600 yr bp and affected areas more than 7 m above high tide at distances of 80 km from the volcano on the kenai peninsula a tsunami deposit dated to ca 3600 yr bp is tentatively correlated with a southward directed collapse of the summit of redoubt volcano although little is known about the magnitude of the tsunami the 1600 yr bp tsunami from augustine volcano occurred about the same time as the collapse of the well developed kachemak culture in the southern cook inlet area suggesting a link between volcanic tsunamis and prehistoric cultural changes in this region of alaska

myth and geology this book is the first peer reviewed collection of papers focusing on the potential of myth storylines to yield data and lessons that are of value to the geological sciences building on the nascent discipline of geomythology scientists and scholars from a variety of disciplines have contributed to this volume the geological hazards such as earthquakes tsunamis volcanic eruptions and cosmic impacts that have given rise to myths are considered as are the sacred and cultural values associated with rocks fossils geological formations and landscapes there are also discussions about the historical and literary perspectives of geomythology regional coverage includes europe and the mediterranean afghanistan cameroon india australia japan pacific islands south america and north america myth and geology challenges the widespread notion that myths are fictitious or otherwise lacking in value for the physical sciences

volcanoes in the pre columbian life legend and archaeology of costa rica central america costa rica is located geographically in the southern part of the central american volcanic front a zone where interaction between the mesoamerican and south american cultures occurred in pre columbian times several volcanoes violently erupted during the holocene when the first nomadic human hunters and later settlers were present volcanic rocks were the most important geo resource in making artifacts and as construction materials for pre columbian inhabitants some pottery products are believed to resemble smoking volcanoes and the settlements around volcanoes would seem to indicate their influence on daily life undoubtedly volcanic eruptions disrupted the life of early settlers particularly in the vicinity of arenal and irazu volcanoes where archaeological remains show transient effects and displacement caused by periodical eruptions but later resilient occupations around the volcanoes most native languages are extinct with the exception of those presently spoken in areas far away from active volcanoes where no words are related to volcanic phenomena or structures the preserved legends are ambiguous suggesting that they were either produced during the early spanish conquest or were altered following the pre columbian period

the volcanic environment for 40 000 years of human occupation on the willaumez isthmus west new britain papua new guinea abstract the stratigraphic sequence of 22 tephra beds and their associated paleosols at two sites selected from our studies in west new britain papua new guinea provide the essential environmental background for understanding human responses to c 40 ka years of volcanic activity lithology grain size and mineralogy of the tephras interpreted for the first time elucidate the varying volcanic provenance especially of the pleistocene beds and the environmental conditions which former inhabitants experienced this sequence provides an important long term record of how humans coped with volcanic adversity in papua new guinea the stratigraphic record contains abundant evidence for human settlement during the intervals between volcanic eruptions following plinian and subplinian eruptions people abandoned the region for significant periods of time in some cases these cataclysmic events caused major cultural disasters characterised by local population extinction and loss of some significant types of cultural behaviour despite the punctuated record of settlement and changes in material culture over the long term human populations found effective ways to maintain themselves within an active volcanic environment key responses included persistence of mobile and flexible settlement patterns planned and staged uses of raw materials social exchange and increasing levels of landscape management

magnetic susceptibility variations in upper pleistocene deep sea sediments of the ne atlantic implications for ice rafting and paleocirculation at the last glacial maximum magnetic susceptibility ms variations are used to intercorrelate 17 upper pleistocene sediment cores taken from the ne atlantic between 40 degrees and 60 degrees n the ms based correlation depends on regionally consistent patterns of variation in the deposition of ice rafted detritus ird in response to pleistocene glaciations and especially to high frequency ice rafting episodes referred to in recent studies as heinrich events the sedimentological and rock magnetic basis for the apparent relationship between the ms signal and ird content of ne atlantic sediments is examined by 1 comparing the ms profiles of selected cores with their records of coarse fraction 150 mu m lithic fragment abundance and neogloboquadrina pachyderma sin percentages and 2 normalizing ms by expressing it both on a carbonate free basis and as a quotient with anhysteretic remanent magnetization a parameter sensitive to magnetic mineral grain size variations these comparisons show that variations in bulk sediment ms are only partly driven by simple carbonate dilution productivity and dissolution effects changes in both the concentration and grain size of magnetic minerals within the lithogenic noncarbonate fraction also impose a significant influence on bulk ms values in particular horizons rich in ird are associated with significant increases in the relative proportion of coarse grained multidomain ferrimagnetic particles in the sediment this is because ice rafting in contrast to most other mechanisms capable of transporting detrital magnetic minerals to pelagic environments has a high potential for delivering large ferrimagnetic grains as components of sand sized polycrystalline lithic fragments this fundamental linkage between the ird content and ms signal of ne atlantic sediments is used to reconstruct the patterns of variation in ird deposition and by inference surface currents of the last glacial maximum lgm similar to 18 19 ka relative to the present day ne atlantic using the time slice mapping approach developed by the climap project group our lgm holocene ms ratio map based on sample pairs from over 80 deep sea cores confirms that there was a weak cyclonic gyre north of the polar front in the lgm north atlantic the gyre comprised a sluggish warm current in the ne atlantic flowing north between latitudes 47 degrees and 62 degrees n partly fed by subtropical waters from south of the polar front and carrying large numbers of icebergs derived from several sources most of which melted between latitudes 45 degrees and 52 degrees n the warm current probably continued its flow into the iceland basin where it fed into a south flowing current which transported melting icebergs from iceland and scandinavia along the western flank of the reykjanes ridge

quantitative interpretation of fossil pollen spectra dissimilarity coefficients and the method of modern analogs abstract dissimilarity coefficients measure the difference between multivariate samples and provide a quantitative aid to the identification of modern analogs for fossil pollen samples how eight coefficients responded to differences among modern pollen samples from eastern north america was tested these coefficients represent three different classes 1 unweighted coefficients that are most strongly influenced by large valued pollen types 2 equal weight coefficients that weight all pollen types equally but can be too sensitive to variations among rare types and 3 signal0to noise coefficients that are intermediate in their weighting of pollen types the studies with modern pollen allowed definition of critical values for each coefficient which when not exceeded indicate that two pollen samples originate from the same vegetation region dissimilarity coefficients were used to compare modern and fossil pollen samples and modern samples so similar to fossil samples were found that most of three late quaternary pollen diagrams could be reconstructed by substituting modern samples for fossil samples when the coefficients indicated that the fossil spectra had no modern analogs then the reconstructed diagrams did not match all aspects of the originals no modern analogs existed for samples from before 9300 yr b p at kirchner marsh minnesota and from before 11 000 yr b p at wintergreen lake michigan but modern analogs existed for almost all holocene samples from these two sites and brandreth bog new york

precursory phenomena and destructive events related to the late bronze age minoan thera greece and ad 79 vesuvius italy plinian eruptions inferences from the stratigraphy in the archaeological areas

the 1985 nevado del ruiz volcano catastrophe anatomy and retrospection abstract this paper seeks to analyze in an objective way the circumstances and events that contributed to the 1985 nevado del ruiz catastrophe in order to provide useful guidelines for future emergencies the paper is organized into two principal parts in the first part an anatomy of the catastrophe is developed as a step by step chronicle of events and actions taken by individuals and organizations during the period november 1984 through november 1985 this chronicle provides the essential background for the crucial events of november 13 this year long period is broken down further to emphasize important chapters the gradual awareness of the awakening of the volcano a long period of institutional skepticism reflecting an absence of credibility the closure of the credibility gap with the september 11 phreatic eruption followed by an intensive effort to gird for the worst and a detailed account of the day of reckoning the second part of the paper retrospection examines the numerous complicated factors that influenced the catastrophic outcome and attempts to cull a few lessons from armero in order to avoid similar occurrences in the future in a nutshell the government on the whole acted responsibly but was not willing to bear the economic or political costs of early evacuation or a false alarm science accurately foresaw the hazards but was insufficiently precise to render reliable warning of the crucial event at the last possible minute catastrophe was therefore a calculated risk and this combination the limitations of prediction detection the refusal to bear a false alarm and the lack of will to act on the uncertain information available provided its immediate and most obvious causes but because the crucial event occurred just two days before the armero emergency management plan was to be critically examined and improved the numerous circumstances which delayed progress of emergency management over the previous year also may be said to have contributed to the outcome thus the catastrophe was not caused by technological ineffectiveness or defectiveness nor by an overwhelming eruption or by an improbable run of bad luck but rather by cumulative human error by misjudgment indecision and bureaucratic shortsightedness armero could have produced no victims and therein dwells its immense tragedy

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

sedimentation and climate induced sediments on feni ridge northeast atlantic ocean abstract feni ridge has been studied in detail in the area between 54 and 56 n and 12 and 16 w by using high resolution profiling water column sampling with transmissometer and ctd and by piston and box core sampling the crest of feni ridge is absent in the north of the study area but on passing towards the south it begins to take shape and to increase in height its distance from the rockall slope also increases towards the south on the lower southeastern flank a secondary ridge crest has locally developed and sediment waves along the flanks have amplitudes of up to 45 m the highest and steepest waves are found in the south the waves in the north being somewhat lower bottom nepheloid layers of 175 m near the foot of rockall plateau and 125 m near the crest are attributed to a norwegian sea overflow water current with a core at 2100 m bottom nepheloid layers of 75 100 m on the lower flanks of the ridge are thought to have been caused by northeast atlantic deep water piston cores reflect alternations of glacial and interglacial periods interglacials have a high carbonate and corg content a positive eu anomaly and negative ce anomaly and a low rb la ratio they are dominated by a subpolar and transitional foraminiferal assemblage glacials show a low carbonate and corg content a reduced eu anomaly and a high rb la ratio suggesting increasingly continental sediment sources these deposits are dominated by a polar planktonic foraminiferal assemblage characterized by n pachyderma s and g quinqueloba sedimentation rates reflect differential deposition at crestal station na 87 25 rates are 17 1 cm k y for stage 1 14 6 cm k y for stage 2 3 4 cm k y for stage 3 and 5 4 cm k y for stage 4 stage 5a e has a mean sedimentation rate of 6 1 cm k y over the last 125 k y the development of feni ridge has taken place under a relatively low energy current regime

the 1717 eruption of volcan de fuego guatemala cascading hazards and societal response assessing and communicating the risks posed by natural hazards requires not only a thorough understanding of the hazards themselves but also an understanding of the spatial and temporal impact of successive events from the same source s this approach is enhanced by the lens of time which is often missing from modern responses to recent hazards archaeological studies in contrast examine the longterm consequences of hazardous events but often lack details of the event chronology and immediate human impact that are available for recent events here we show ways in which historical records can bridge the gap between modern and prehistoric studies we focus on the volcanically and seismically active region that hosts the capital city of guatemala a city that has been relocated twice in response to hazardous events since its original founding in 1527 more specifically we examine documents e autos hechos sobre el lastimoso estrago y ruina que padecio esta ciudad de guatemala autos e that were collected in response to a cascading sequence of volcanic seismic and mudflow events in 1717 to support a request to the spanish government to relocate the capital city for a second time these documents provide exceptional detail about the location of the witnesses the nature of the hazardous activity and the response of local communities this detail allows us not only to reconstruct the sequence of events

high frequency climate linkages between the north atlantic and the mediterranean during marine oxygen isotope stage 100 mis100 high resolution records of mediterranean and north atlantic deep sea sediments indicate that rapid changes in hydrology and climate occurred during marine oxygen isotope stage 100 mis100 at 2 52 ma which exhibits characteristics similar to late pleistocene dansgaard oeschger bond cycles and heinrich events as in the late pleistocene north atlantic oceanographic and atmospheric changes were probably transmitted into the mediterranean by some combination of surface water inflow and atlantic mediterranean atmospheric pressure gradients our data suggest that the mechanism s responsible for sub milankovitch and millennial scale climate oscillations were the same over at least the past 2 6 ma notwithstanding the transition from the 41 kyr dominated glacial cycles of the late pliocene to the 100 kyr cycles of the late pleistocene

geology and eruptive history of unzen volcano shimabara peninsula kyushu sw japan abstract during the past 500 thousand years unzen volcano an active composite volcano in the southwest japan arc has erupted lavas and pyroclastic materials of andesite to dacite composition and has developed a volcanotectonic graben the volcano can be divided into the older and the younger unzen volcanoes the exposed rocks of the older unzen volcano are composed of thick lava flows and pyroclastic deposits dated around 200 300 ka drill cores recovered from the basal part of the older unzen volcano are dated at 400 500 ka the volcanic rocks of the older unzen exceed 120 km3 in volume the younger unzen volcano is composed of lava domes and pyroclastic deposits mostly younger than 100 ka this younger volcanic edifice comprises nodake myokendake fugendake and mayuyama volcanoes nodake myokendake and fugendake volcanoes are 100 70 ka 30 20 ka and

large arctic temperature change at the wisconsin holocene glacial transition analysis of borehole temperature and greenland ice sheet project ii ice core isotopic composition reveals that the warming from average glacial conditions to the holocene in central greenland was large approximately 15 c this is at least three times the coincident temperature change in the tropics and mid latitudes the coldest periods of the last glacial were probably 21 c colder than at present over the greenland ice sheet

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

interaction of pyroclastic density currents with human settlements evidence from ancient pompeii integrating field observations and rock magnetic measurements we report how a turbulent pyroclastic density current interacted with and moved through an urban area the data are from the most energetic turbulent pyroclastic density current of the a d 79 eruption of vesuvius italy which partially destroyed the roman city of pompeii our results show that the urban fabric was able to divide the lower portion of the current into several streams that followed the city walls and the intracity roads vortices revealed by upstream particle orientations and decreases in deposit temperature formed downflow of obstacles or inside cavities although these perturbations affected only the lower part of the current and were localized they could represent in certain cases cooler zones within which chances of human survival are increased our integrated field data for pyroclastic density current temperature and flow direction collected for the first time across an urban environment enable verification of coupled thermodynamic numerical models and their hazard simulation abilities

evidence for general instability of past climate from a 250 kyr ice core record recent results1 2 from two ice cores drilled in central greenland have revealed large abrupt climate changes of at least regional extent during the late stages of the last glaciation suggesting that climate in the north atlantic region is able to reorganize itself rapidly perhaps even within a few decades here we present a detailed stable isotope record for the full length of the greenland ice core project summit ice core extending over the past 250 kyr according to a calculated timescale we find that climate instability was not confined to the last glaciation but appears also to have been marked during the last interglacial as explored more fully in a companion paper3 and during the previous saale holstein glacial cycle this is in contrast with the extreme stability of the holocene suggesting that recent climate stability may be the exception rather than the rule the last interglacial seems to have lasted longer than is implied by the deep sea specmap record4 in agreement with other land based observations5 6 we suggest that climate instability in the early part of the last interglacial may have delayed the melting of the saalean ice sheets in america and eurasia perhaps accounting for this discrepancy

evidence for massive discharges of icebergs into the north atlantic ocean during the last glacial period sediments in the north atlantic ocean contain a series of layers that are rich in ice rafted debris and unusually poor in foraminifera1 here we present evidence that the most recent six of these heinrich layers deposited between 14 000 and 70 000 years ago record marked decreases in sea surface temperature and salinity decreases in the flux of planktonic foraminifera to the sediments and short lived massive discharges of icebergs originating in eastern canada the path of the icebergs clearly marked by the presence of ice rafted detrital carbonate can be traced for more than 3 000 km a remarkable distance attesting to extreme cooling of surface waters and enormous amounts of drifting ice the cause of these extreme events is puzzling they may reflect repeated rapid advances of the laurentide ice sheet perhaps associated with reductions in air temperatures yet temperature records from greenland ice cores appear to exhibit only a weak corresponding signal moreover the 5 10 000 yr intervals between the events are inconsistent with milankovitch orbital periodicities raising the question of what the ultimate cause of the postulated cooling may have been

millennial scale oceanic climate variability off the western iberian margin during the last two glacial periods high resolution palaeoclimate records recovered from the iberian margin in core md95 2040 exhibit large fluctuations in oceanographic conditions over the last 190 ka large scale cooling of the surface ocean is indicated by the presence of the polar planktonic foraminifer neogloboquadrina pachyderma sinistral and in some instances the occurrence of ice rafted debris ird ice rafting episodes were prevalent in both of the last two glacials with greater intensity in stages 2 through 4 than in stage 6 the six youngest heinrich events are well defined during the last glacial but detrital carbonate is absent from heinrich layers hl6 hl5 and hl3 dansgaard oeschger stadial equivalent sub millennial ird deposition events have been detected in particular during stage 3 allowing a good match with the cooling displayed in the greenland ice core gisp2 sea surface temperature off portugal in stage 6 was in general warmer than during the last glacial pointing towards a weaker southward influence of polar water masses ice rafting occurred mainly in mid mis marine isotope stage 6 between 173 and 153 kyr as a group of poorly differentiated short duration quasi continuous events mainly marked by the high abundance of sinistral n pachyderma differences exist in ird composition relative to the last glacial with a reduced canadian derived detrital carbonate component combined with an important contribution of volcanic particles the lower magnitude and higher frequency of these events suggest that the higher temperatures would have induced iceberg waning closer to the source areas

high resolution stratigraphy of the faeroe shetland channel and its relation to north atlantic paleoceanography the last 87 kyr abstract two piston cores from the faeroe shetland channel have been investigated for stratigraphic and paleoceanographic correlation with atlantic ocean and norwegian sea records the high resolution cores have been analyzed for the downcore distribution of planktic and benthic foraminifera and oxygen isotopes ams 14 c dates and the position of ash layers i and ii form the basis for the correlation core na81 10 covers the period from isotope stage 3 to recent stage 1 while core na81 04 covers isotope stages 5a to 1 the holocene is well represented in core na81 10 by 2 m of sediment whereas it is only 50 cm in core na81 04 which is situated directly under the main core of the norwegian sea deep water outflow the transition of isotope stage 2 to stage 1 is affected by dissolution and thus is less clearly represented ams 14 c dates show that termination ia begins at 16 ka and ends at about the 13 ka level the last glacial maximum lgm defined at 19 16 ka is characterized by an ird peak faunal planktic foraminifera maxima dated at 17 3 and 18 25 ka and a high percentage of globigerina quinqueloba apparently open water conditions and circulation within the norwegian sea prevailed at least from 22 5 to 14 8 ka during the greatest part of stage 2 including the lgm and well onto termination ia a preservation maximum is observed throughout stage 2 isotope stage 3 with a nearly complete record of isotope substages is well represented in both cores oxygen isotope depletion peaks correlate with fauna minima and in time to north atlantic heinrich events h5 h1 faunal data indicate that deep water is generated within the norwegian greenland sea repeatedly since 26 ka with stops prior to 26 ka 22 5 20 8 20 5 ka and between 14 9 and 13 ka h3 h2 and h1 all isotope depletion peaks since ca 50 ka are anticorrelated with fauna and are mainly controlled by surface salinity changes isotope stages and substages are directly correlated to fauna peaks and temperature between 87 and ca 50 ka the faeroe shetland channel record shows that repeated presences of atlantic surface water and deep convection alternating with convection shutdowns have occurred within the norwegian sea greenland sea from the beginning of stages 5a to 1

volcanism and human prehistory in arabia abstract the cenozoic harrats lavafields of western arabia constitute one of the major volcanic areas of the world recent precise chronometric dating of volcanic rocks in harrat rahat makes it possible to outline a detailed chronology of volcanic activity likewise recent advances in archaeology have demonstrated that early humans repeatedly occupied the arabian peninsula in the pleistocene most archaeological sites in arabia correlate with phases of increased rainfall such as interglacials however we should be cautious about reducing the prehistory of arabia to simply the story of rainfall fluctuation this paper explores the impacts of volcanism on human populations in arabia as a case study of causality and scale in human environment interactions periodic environmental windows of opportunity allowed early human groups to expand into western arabia however the western highlands are also home to volcanically active areas that saw repeated eruptions in the holocene a major eruption occurred in western arabia around every 300 years and the emerging evidence for pleistocene volcanism demonstrates repeated major eruptions at the same times as early humans were occupying the area as well as offering a review of human volcanism interactions in arabian prehistory a model is proposed in which volcanic activity in western arabia may have facilitated further population dispersal as well as negative health impacts as a push factor a balanced perspective on the impacts of volcanism and associated phenomena such as earthquakes emphasises possibly positive impacts in terms of factors such as water availability and the formation of fertile volcanic soils these positive impacts may have offered pull factors and facilitated regional occupation longer than would be predicted based on climatic variables alone this framework offers not only an explanation for some of the characteristics of the arabian archaeological record but potentially offers part of the explanation for how early human populations were able to pass through the saharo arabian arid belt from our african birthplace to populate the rest of the world

a geochemical criterion for the recognition of heinrich events and estimation of their depositional fluxes by the 230thexcess 0 profiling method abstract a core from the armorican seamount 46 23 8 n 12 32 8 w 3849 m in the deep ne atlantic southwest of the british isles exhibits unusual mg al ratios in the sediments deposited during the last glacial period high mg al ratio values are restricted within layers of 14 cm thick and mark the presence of ice rafted detrital material deposited by heinrich events h1 h2 and h4 these peaks in the ratio are caused by local increases in the dolomite quartz and feldspar content and concomitant dilutions in the phyllosilicate content which overall increase mg and decrease al the known times of the heinrich events provide a chronology for the core and indicate a considerably slower mean sediment accumulation rate during and after the glacial interglacial transition 2 2 cm ky 1 than in earlier glacial times mean 5 6 cm ky 1 within the glacial however 230 th excess 0 profiling demonstrates that accumulation fluxes were at least 7 higher than normal during the deposition of heinrich events up to 25 g cm 2 ky 1 versus a background glacial level of 3 7 g cm 2 ky 1 because of post depositional bioturbation peak fluxes are likely to have been even higher the 230 th excess 0 method also reveals the presence of event h3 which bears minor dolomite and is the least well developed of the last four heinrich events despite the marked compositional and flux variations the total mass deposited at this site is estimated at only 2 4 4 9 and 7 9 g cm 2 for events h1 h2 and h4 respectively these inventories were deposited over maximum periods of 2 0 1 1 and 0 7 ky respectively but delivery could have been much more rapid of the order of a few hundred years

changes in sea surface hydrology associated with heinrich event 4 in the north atlantic ocean between 40 and 60 n abstract the changes in distribution of sea surface temperature and salinity in the north atlantic between 40 and 60 n were reconstructed for the time interval between 40 and 30 kyr bp which includes the large iceberg discharge event associated with the deposition of heinrich layer 4 we found that the meltwater input during deposition of heinrich layer 4 resulted in a 1 2 kyr temperature decrease of about 2 c and a salinity decrease in the range of 1 5 3 5 between 40 and 50 n sites above 50 n did not experience significant salinity variations a much larger area was affected by the reduction in sea surface temperature the amplitude of the sea surface temperature shift was however much smaller than the atmospheric temperature changes over greenland at gisp and grip sites

age dating and the orbital theory of the ice ages development of a high resolution 0 to 300 000 year chronostratigraphy using the concept of orbital tuning a continuous high resolution deep sea chronostratigraphy has been developed spanning the last 300 000 yr the chronology is developed using a stacked oxygen isotope stratigraphy and four different orbital tuning approaches each of which is based upon a different assumption concerning the response of the orbital signal recorded in the data each approach yields a separate chronology the error measured by the standard deviation about the average of these four results which represents the best chronology has an average magnitude of only 2500 yr this small value indicates that the chronology produced is insensitive to the specific orbital tuning technique used excellent convergence between chronologies developed using each of five different paleoclimatological indicators from a single core is also obtained the resultant chronology is also insensitive to the specific indicator used the error associated with each tuning approach is estimated independently and propagated through to the average result the resulting error estimate is independent of that associated with the degree of convergence and has an average magnitude of 3500 yr in excellent agreement with the 2500 yr estimate transfer of the final chronology to the stacked record leads to an estimated error of 1500 yr thus the final chronology has an average error of 5000 yr