holocene climatic changes and vegetation development in the kuril islands abstract the response of kuril island vegetation to climatic changes during the holocene is reconstructed from data obtained from key sections that included various depositional environments these climatic fluctuations were not as marked in the kuril archipelago as they were in nearby continental margins and large islands during the early holocene dwarf stone pine coniferous and birch forest prevailed in the south kurils and tundra landscapes in the north kurils the greatest northward movement of kuril vegetation zones occurred during the holocene optimum 6600 5000 14c bp mean annual temperatures in the kuril islands were 2 3 c higher than modern shifts in the location of warm and cold marine currents which strengthened or dampened insolation driven climatic changes played an important role in vegetation development cool temperate broadleaf forests and mixed coniferous broadleaf forests were widespread on south kurils rising holocene sea levels flooded land bridge connections to hokkaido island and the mainland resulting in the formation of several small islands in the south kurils meadows and boggy landscapes prevailed this flooding had a great effect on repopulation of island biota as did the deep straits that separate southern islands from the central and north kurils all paleovegetation associations can be found on the current landscape although their geographic distribution has changed during the holocene no introduction of plants from adjacent land occurred in the holocene forb and graminoid meadows characterized the middle holocene vegetation of central kurils on north kurils forb meadows were widespread tundra area decreased climatic changes did not occur synchronously throughout the kurils at times not even on the closest islands local volcanism played a special role in kuril vegetation history the considerable microclimatic variability within the islands also has been important in determining the development and preservation of vegetation communities and their reaction to more regional climatic changes

the sensitivity of seafloor compliance to two dimensional low velocity anomalies summary seafloor compliance the deformation of the seafloor under pressure forcing by long wavelength ocean surface waves is a passive source geophysical measurement that is particularly sensitive to subsurface s wave velocity existing inversions of seafloor compliance data for s wave structure assume a 1 d velocity model whereas in reality there may be significant lateral velocity variation the effect of 2 d structure on compliance measurements has previously been investigated using finite differences but computational constraints limit the number and type of models that can be tested we present a quasi analytical calculation of seafloor compliance over a cylinder that allows us to efficiently investigate the effect of an important subset of subsurface models including pure fluid inclusions the compliance displays the same sensitivity to regions of low shear modulus as is seen for 1 d situations generating a strong peak over the low velocity zone the spatial width of this peak which is a measure of the horizontal resolution of seafloor compliance is approximately proportional to the depth of the cylinder while its amplitude is controlled by the radius and depth of the cylinder and the s wave speed of the cylinder and the background minimum structure 1 d inversions of the compliance measured above a fluid cylinder recover distinct low velocity zones although the recovered s wave speed is much greater than zero and the low velocity zone is smeared out over a greater depth range than that occupied by the cylinder

the calamine nonsulfide zn pb deposits of belgium petrographical mineralogical and geochemical characterization abstract the belgian nonsulfide zn deposits represent the historical basis for the zinc mining and smelting industry in europe the zinc ores were called calamines and consist of a mixture of zn carbonates smithsonite hydrozincite and zn silicates hemimorphite willemite and zn clays with a variable content of pb minerals the calamines are considered to be oxidation products of primary sulfide ores the most important was the la calamine orebody more than 600 000 tons of zn metal that was continuously exploited for several centuries nonsulfide ores were also exploited at schmalgraf engis dickenbusch fossey rocheux oneux welkenraedt and in other smaller deposits all no longer accessible for study where the calamines extended from the surface to an average depth of 40 to 50 m the primary zn pb sulfide mineralization consists of post variscan hydrothermal veins and replacement bodies mostly occurring in the dinantian visean limestones the sulfides intersect the paleozoic rocks and are truncated and unconformably covered by late cretaceous sediments santonian aachen fm the same setting has been observed for the nonsulfide ores suggesting an early to mid cretaceous weathering consistent with other geological and geochronological data on paleoweathering in europe the extensive occurrence of willemite that appears to be the first deposited nonsulfide mineral is a striking particularity of the belgian calamines most fluid inclusions in willemite 80 and all inclusions in smithsonite are monophase aqueous ice melting temperatures suggest salinities between 0 and 5 wt nacl equiv homogenization temperatures of rare two phase inclusions liquid vapor in willemite display a large variation between 80 and 190 an interval matching the temperature ranges of other willemite ores throughout the world so far considered of hydrothermal origin the stable isotope variation of belgian smithsonites and cerussites is very similar to the range measured in other supergene nonsulfide deposits similar to those of sw sardinia belgian smithsonites exhibit a limited range of 18o values from 27 1 to 30 6 averaging 28 4 0 8 v smow this limited range points to a relatively uniform isotope composition of the oxidizing waters and constant temperatures of smithsonite crystallization carbon isotope values even from the same mine show a considerable range from 11 6 to 1 6 this extensive range indicates at least two carbon sources 13c depleted carbon derived from the organic matter in the soils and 13c enriched carbon originating from marine carbonate host rocks cerussites have oxygen isotope values ranging from 16 8 to 19 3 averaging 17 8 1 0 and carbon isotope values of 18 4 to 14 7 the metallic deposits of eastern belgium have undergone a polyphase history which started with a possibly jurassic sulfide mineralization followed by oxidation under high silica activities and consequently by supergene weathering owing to structure and mineralogical association we do not consider the high homogenization temperatures as reliable minimum temperature estimates of willemite formation however it is possible that the willemite concentrations could have been derived from low temperature localized hydrothermal processes caused by deeply reaching oxidizing fluids smithsonite and hemimorphite often developed at the expenses of willemite have all the characteristics of supergene oxidation products

the influence of temperature ph and growth rate on the δ18o composition of inorganically precipitated calcite abstract the oxygen isotope composition of carbonate minerals varies with temperature as well as other environmental variables for carbonates that precipitate slowly under conditions that approach thermodynamic equilibrium the temperature dependence of 18 o uptake is the dominant signal and the measured 18 o content can be used as a paleotemperature proxy in the more common case where carbonate minerals grow in a regime where they are not in isotopic equilibrium with their host solution their oxygen isotope compositions are a convolution of multiple environmental variables here we present results from calcite growth experiments demonstrating the occurrence of large 2 non equilibrium oxygen isotope effects under conditions relevant to biogenic calcite growth and many natural inorganic systems we show that these non equilibrium effects vary systematically with ph and crystal growth rate an isotopic ion by ion crystal growth model quantifies the competing roles of temperature ph and growth rate and provides a general description of calcite water oxygen isotope fractionation under non equilibrium conditions the crystal growth model results show that 1 there are both equilibrium and kinetic contributions to calcite oxygen isotopes at biogenic growth rates 2 calcite does not directly inherit the oxygen isotope composition of dic even at fast growth rates 3 there is a kinetically controlled variation of about 1 per ph unit between ph 7 7 and 9 3 at constant growth rate for inorganic calcite as well as biogenic calcite and 4 extreme light isotope enrichments in calcite in alkaline environments are likely due to disequilibrium among dic species in aqueous solution the model can be extended to 13 c uptake into carbonates as well as clumped isotopes but additional data are needed to constrain the kinetic fractionation factors for carbon isotopes the experimental and model results constitute an important step in separating the relative influence of inorganic and biologic processes on isotopic fractionation and may aid the development of new paleoproxies based on non equilibrium effects

oxygen isotope fractionation during smithsonite formation from aqueous solutions abstract oxygen isotope fractionation between carbonate minerals and water is used as an environmental proxy to estimate mineral formation temperatures or isotopic composition of precipitating fluids to date no experimental data on the oxygen isotope fractionation factor between smithsonite znco3 and water 18o smithsonite water 18o 16o smithsonite 18o 16o water exist therefore in the present study experimental work on smithsonite synthesis in the temperature range between 25 and 80 c is coupled with ab initio based theoretical calculations laboratory precipitation experiments took place in titanium reactors at elevated pco2 10 atm in order to induce the formation of smithsonite from hydrozincite zn5 co3 2 oh 6 which is the precursor phase initially formed at 25 c and low pco2 ph 6 8 the constant 18o smithsonite water 1000 18osmithonite 1000 18owater value reached at a reaction time 10 000 min 7 days suggests near equilibrium conditions based on the experimentally obtained temperature relation of 18o smithsonite water at 25 40 60 and 80 c the integrated equation can be linearly described by the function 10 3 ln 18 o smithsonite water 2 79 10 6 t 2 0 95 0 06 10 6 t 2 0 60 where the temperature is in kelvin the ab initio calculations suggest that this relation can be described in the temperature range from 0 to 100 c as 10 3 ln smithsonite liquid water 3 21 10 6 t 2 3 63 0 025 10 6 t 2 0 90 the 18o smithsonite water values from the experimental approach fit within error to the theoretical relationship from the literature and the above ab initio calculations difference in slope between the experiment and theoretical obtained equation likely reflects modeling inaccuracies whereas kinetic effects cannot be completely ruled out in the experimental approach the obtained 18o smithsonite water values match with the general sequence of zn2

equilibrium oxygen hydrogen and carbon isotope fractionation factors applicable to geologic systems as demonstrated by the chapters in this short course stable isotope techniques are an important tool in almost every branch of the earth sciences central to many of these applications is a quantitative understanding of equilibrium isotope partitioning between substances indeed it was harold urey s 1947 thermodynamically based estimate of the temperature dependence of 18o 16o fractionation between calcium carbonate and water and a recognition of how this information might be used to determine the temperatures of ancient oceans that launched the science of stable isotope geochemistry the approach pioneered by urey has since been used to estimate temperatures for a wide range of geological processes e g emiliani 1955 anderson et al 1971 clayton 1986 valley this volume in addition to their geothermometric applications equilibrium fractionation data are also important in the study of fluid rock interactions including those associated with diagenetic hydrothermal and metamorphic processes baumgartner and valley this volume shanks this volume finally a knowledge of equilibrium fractionation is a necessary first step in evaluating isotopic disequilibrium a widespread phenomenon that is increasingly being used to study temporal relationships in geological systems cole and chakraborty this volume in the fifty four years since the publication of urey s paper equilibrium fractionation data have been reported for many minerals and fluids of geological interest these data were derived from 1 theoretical calculations following the methods developed by urey 1947 and bigeleisen and mayer 1947 2 direct laboratory experiments 3 semi empirical bond strength models and 4 measurement of fractionations in natural samples each of these methods has its advantages and disadvantages however the availability of a variety of methods for calibrating fractionation factors has led to a plethora of calibrations not all of which are in agreement in this chapter we evaluate the major methods for determining fractionation factors

late holocene history of tokotan lake kuril archipelago russian far east the use of lacustrine records for paleoclimatic reconstructions from geologically dynamic settings abstract a high resolution multiproxy analysis of a core from tokotan lake urup island illustrates the complex paleoenvironmental signals that can be preserved in sedimentary deposits from geologically active areas such as the kuril archipelago diatom and geochemical analyses of the tokotan core suggest a shallowing and lessening of the lake area over the last 3450 cal bp without other proxies the record could be interpreted as showing a general decrease in precipitation over the late holocene however palynological data indicate no change in vegetation thereby implying no significant climatic variation neither of these paleoclimatic interpretations agrees with late holocene reconstructions from the kuril archipelago or the russian mainland paleomagnetic data imply variable sediment sources during the lake s history indicating alterations within the tokotan catchment e g shifts in gradients or sediment loads in the inflowing streams such changes would be particularly important in the shabalina river which today has formed a partial dam across the lake s outlet the results of the tokotan study indicate that other factors e g volcanism seismic activity sea level changes rather than climate were more probable determinants of the late holocene lake record given the geologic dynamism of the region it is perhaps not surprising that paleo records from the kuril islands display an inconsistency in the numbers and or duration of proposed holocene climatic oscillations underscoring the importance of multiproxy investigations in areas that are or have been geologically dynamic

holocene environments of central iturup island southern kuril archipelago russian far east two lake records document holocene changes in sea level vegetation and climate on the okhotsk and pacific sides of central iturup island southern kuril islands the sediment cores originated within tidal flats that subsequently developed into a marine strait which crosscut the island as sea levels rose during the early holocene brackish lagoons and eventually freshwater lakes formed by 7100 cal yr bp associated with warmer than present conditions past vegetation changes indicate a clear holocene thermal maximum recorded on the pacific coast but a less distinct optimum on the western shores 7200 6100 cal yr bp a gradual cooling toward modern levels occurred 6100 3500 cal yr bp four prominent layers of coarse sediment found in mid to late holocene lake deposits may correspond to intervals of climate cooling dune formation previously documented in coastal sections although chronological limitations question the synchronicity of these events across the south russian far east it seems probable that they have a regional signature however the mechanisms responsible for holocene climatic changes are likely the result of complex interactions of hemispheric scale atmospheric patterns marine characteristics and regional feedbacks rather than simply fluctuations in sea levels as suggested in the current interpretative model

changes in temperature and water depth of a small mountain lake during the past 3000 years in central kamchatka reflected by a chironomid record abstract we investigated chironomid assemblages of a well dated sediment core from a small seepage lake situated at the eastern slope of the central kamchatka mountain chain far east russia the chironomid fauna of the investigated sigrid lake is dominated by littoral taxa that are sensitive to fluctuations of the water level two groups of taxa interchangeably dominate the record responding to the changes in the lake environment during the past 2800 years the first group of littoral phytophilic taxa includes psectrocladius sordidellus type corynoneura arctica type and dicrotendipes nervosus type the abundances of the taxa from this group have the strongest influence on the variations of pca 1 and these taxa mostly correspond to low water levels moderate temperatures and slightly acidified conditions the second group of taxa includes microtendipes pedellus type tanytarsus lugens type and tanytarsus pallidicornis type the variations in the abundances of these taxa and especially of m pedellus type are in accordance with pca 2 and correspond to the higher water level in the lake more oligotrophic and neutral ph conditions water depths wd were reconstructed using a modern chironomid based temperature and water depth calibration data set training set and inference model from east siberia nazarova et al 2011 mean july air temperatures t july were inferred using a chironomid based temperature inference model based on a modern calibration data set for the far east nazarova et al 2015 the application of transfer functions resulted in reconstructed t july fluctuations of approximately 3 c over the last 2800 years low temperatures 11 0 12 0 c were reconstructed for the periods between ca 1700 and 1500 cal yr bp corresponding to the kofun cold stage and between ca 1200 and 150 cal yr bp partly corresponding to the little ice age lia warm periods modern t july or higher were reconstructed for the periods between ca 2700 and 1800 cal yr bp 1500 and 1300 cal yr bp and after 150 cal yr bp wd reconstruction revealed that the lake level was lower than its present level at the beginning of the record between ca 2600 and 2300 cal yr bp and ca 550 cal yr bp between ca 2300 and 700 cal yr bp as well as between 450 and 150 cal yr bp the lake level was higher than it is today most probably reflecting more humid conditions

stable isotopes of nonsulphide zn pb ores in britain and ireland fluid characteristics and palaeoclimatic variability stable isotope c o analysis was applied to smithsonites and cerussites from zn pb nonsulphide ores from britain and ireland to determine the nature of the fluids responsible for the precipitation of secondary carbonates and any relationship with palaeoclimatic conditions the carbon isotope compositions of the irish smithsonites show a major contribution of organic carbon whereas those of both zn and pb carbonates in the uk deposits indicate contribution of organic carbon and host rock carbonates 18ovsmow values for cerussite from both areas are about 13 lower than those of smithsonites uk smithsonite 18ovsmow values are more variable than those for cerussites and the irish smithsonites have unusually high values isoscape maps indicate that 18o values for both carbonates are higher in the west and decrease toward the east this trend correlates with a general decrease in the oxygen isotope compositions of rainwater moving eastward and suggests that oxidation of sulphides occurred at temperatures of about 15 20 c under climatic conditions warmer than today supplementary material a comprehensive overview of the investigated sites detailed data for the samples and sem images are available at https doi org 10 6084 m9 figshare c 4579535

two dimensional finite difference model of seafloor compliance summary seafloor compliance is the measure of seafloor deformation under a pressure signal our new 2 d finite difference compliance modelling algorithm presents several advantages over the existing compliance models including the ability to handle any gridded subsurface structure with no limitations on the gradients of the material properties as well as significantly improved performance applying this method to some of the problems inaccessible to previously existing methods demonstrates that lateral variations in subsurface structure must be accounted for to adequately interpret compliance data in areas with significant lateral variations the utilization of 1 d modelling and inversion is likely to result in high interpretation errors even when additional subsurface structure information is available we find that flattened pure melt bodies have a significantly higher compliance than cylindrical melt bodies with the same cross sectional area the compliance created by such bodies often has side peaks over their edges which are as strong as or stronger than the central peak requiring a series of measurements to best constrain their size and shear velocity finally we find that the compliance data are far and away most sensitive to the broad thick lower crustal partial melt zone our simple data fitting model for the compliance measurements on the east pacific rise at 9 48 n required shear velocities as low as 700 m s 1 in the centre of this zone far below the values previously estimated using 1 d model based inversions suggesting higher melt percentages than those previously estimated while small melt bodies in the upper part of the crust were found to have little or no effect on the measured compliance

terrestrial ocean environmental change in the northwestern pacific from the glacial times to holocene abstract the mixed water region mwr between the oyashio current and the kuroshio extension and surrounding terrestrial region have been affected by the global climatic change the sedimentary core kr02 15 pc6 collected at 40 23 8871 n 143 29 8663 e in the mwr provides detailed records of pollen and spores and alkenone sea surface temperature sst during the last 15 kyr showing that both ocean and terrestrial environments have been appreciably linked abundance of picea a proxy for terrestrial cool climate fluctuated coinciding with the alkenone sst change during the interstadial period 15 0 7 7 cal kyr b p alkenone sst increased to the modern level at 8 0 cal kyr b p and remained almost constant until 2 0 kyr b p while the terrestrial warming still continued until 4 0 cal kyr b p the rainfall under terrestrial warm condition increased gradually from 7 9 cal kyr b p and rapidly from 2 0 cal kyr b p both terrestrial and marine environments cooled down during the last 2 kyr possibly due to the intensified cold oyashio current

middle and late holocene environments and vegetation history of kunashir island kurile islands northwestern pacific natural middle and late holocene environmental development of kunashiri island reflects global climatic changes and the migration of warm and cold currents dry and cool climate changed to warm and moist about 7000 6500 bp later than on hokkaido island at this time kuroshio current system became more active on kunashir island birch assemblages were replaced by cool temperate broadleaf forests in the south and mixed coniferous broadleaf forests in the north the highest sea level position reached 2 5 3 m above psl about 6500 6300 bp cooling about 4700 4500 bp island vegetation weakly changed that connected with warm current influence major regression at this period led to formation of extensive coastal dunefields the warming at the beginning of the late holocene was almost similar to the holocene optimum two minor transgressions are recorded about 4010 3400 and 2950 2620 bp active entrance of detrital material to the coastal zone resulted in growth of accumulative landforms vegetation changes and

paleoenvironments of kuril islands in late pleistocene holocene climatic changes and volcanic eruption effects the kuril islands are noted for a variety of landscapes from nemoral broadleaf forests to forest tundra and tundra some large islands display a distinct altitudinal zonality environments of the islands bear evidence of various catastrophic events that controlled the landscape evolution to a considerable extent changes of climate during the pleistocene were of particular importance in evolution of the environments dramatic rapid fluctuations of climate at the late pleistocene holocene boundary resulted in repeated restructuring of landscapes at the land bridge connecting the south kuriles and hokkaido in the southern part of the small kuril ridge open forests might persist until the land mass was broken into small islands dominated by meadow marsh vegetation since the middle holocene on the central and northern kuril islands environmental changes during the middle and late holocene resulted both from climatic fluctuations and from repeated fallout of volcanic ash deposition of organic matter began about 6 5 ka bp it resulted from the onset of more favorable conditions namely warming increase of moisture supply and reduction of volcanic activity the evolution of island landscapes consisted mainly in changes of relative area occupied by various plant communities most of which are present in modern vegetation the holocene climatic optimum was not particularly pronounced in this part of the great kuril ridge some consideration is given to issues of changes in zonal boundaries at different time intervals within late pleistocene and holocene

age source and distribution of holocene tephra in the southern kurile islands evaluation of holocene eruptive activities in the southern kurile arc abstract we identified 32 distinct layers of holocene tephra in the southern kurile islands on the basis of petrological features and 14c ages of soils beneath or above the tephra layers three layers were derived from the volcanoes of kunashir island one from mendeleev volcano ca 2 6 cal ka and two from tyatya volcano 1420 cal bp and ad 1973 fourteen widely distributed silicic tephra layers were derived from four volcanoes in hokkaido mashu rausudake tarumai and hokkaido komagatake a widespread tephra was derived from baitoushan volcano between china and north korea fourteen tephra layers have unknown source volcanoes 1 silicic medium k ash 2 silicic low k ash and 11 scoria pumice ash layers except for the medium k ash these tephra are presumed to be derived from the volcanoes in the kurile islands it has been known that caldera forming eruptions occurred at mashu hokkaido and lvinaya past iturup volcanoes in the early holocene ca 12 8 ka however we did not find any tephra from lvinaya past volcano our results provide evidence of the temporal and spatial evolution of eruptive activity in the southern kurile arc we conclude that the level of the eruptive activity in the southern kurile islands especially kunashir island has been lower than that in eastern hokkaido since 8 ka the islands produced mainly vulcanian and strombolian eruptions of mafic magma whereas eastern hokkaido produced plinian eruptions of silicic magma repeated at intervals of 1000 2000 years

quaternary forest and climate history of hokkaido japan from marine sediments abstract pollen data from quaternary marine sediments deposited in central hokkaido northern japan provide insight into northeast asian vegetation and climatic changes over the last few million years during the early pleistocene coniferous forest dominated by picea and cryptomeria japonica and taiga composed of larix and picea developed under cool wet and cold dry climates respectively strong climatic contrasts are inferred from late pleistocene interglacial and glacial pollen assemblages which precede the last glacial cycle in the former cool temperate broad leaf forest mainly composed of fagus reflects a warmer and wetter climate than now in the latter taiga similar to that now found in northern sakhalin apparently flourished in hokkaido the composition of pollen assemblages correlated with oxygen isotope stage 5 changed from cool temperate forest of quercus ulmus and juglans substage 5e to picea larix taiga substage 5d cool temperate forest of quercus and ulmus substage 5c and picea abies forest substage 5b compared with present conditions climate during stage 5 in northern japan apparently fluctuated from warmer wetter to colder drier taiga composed of picea pinus and larix indicating colder dry conditions during stage 4 was replaced by picea abies forest and picea larix taiga in stage 3 suggesting relatively cool and cold dry environments taiga and mixed forest with taiga and cool temperate components characterize stage 2 holocene forests with juglans betula and quercus juglans were succeeded by picea and abies during the early holocene warm interval 7000 bp subsequently quercus ulmus and abies alnus assemblages reflect climatic deterioration pan mixed forest has been developed in hokkaido since 2000 bp

stable isotope geochemistry of carbonate minerals in supergene oxidation zones of zn pb deposits abstract the 18 o 16 o and 13 c 12 c ratios of carbonate minerals formed by supergene oxidation of zn pb deposits and submarine alteration of ancient slags were studied in order to constrain isotope fractionation factors for smithsonite cerussite and phosgenite and to characterize conditions of nonsulfide ore formation we present new isotope data of carbonate hosted ores from the iglesiente district sardinia italy and vila ruiva portugal as well as from the silicate hosted ores of the broken hill district new south wales australia and freihung germany and review previously published isotope data the temperature dependence of oxygen isotope fractionation between pb and zn carbonate minerals and water below 240 c for cerussite and below 100 c for smithsonite and phosgenite can be expressed as 1000ln cerussite water 2 29 10 6 t 2 3 56 1000ln smithsonite water 3 10 10 6 t 2 3 50 1000ln phosgenite water 2 55 10 6 t 2 3 50 with t in kelvin the carbon isotope fractionation between smithsonite phosgenite hydrozincite and calcite is less than about 2 while cerussites are strongly depleted in 13 c by about 10 as compared to the former minerals oxygen isotope variations of individual carbonate minerals within a deposit are relatively small indicating constant formation temperatures and a single meteoric fluid source average formation temperatures of the studied deposits are calculated at 20 5 c using the estimated isotope compositions of local paleometeoric waters we observe a linear relationship between the isotope values of estimated paleometeoric waters and supergene carbonates thus base metal carbonate minerals from supergene deposits may provide paleoclimatic information the carbon isotope values are in most carbonate hosted deposits highly variable more than 10 suggesting at least two isotopically distinct carbon sources the isotopically light component can be related to oxidation of c3 plants soil derived carbon and or microbes that take active part in sulfide oxidation while the isotopically heavy component originates from carbonate carbon from wall rocks and or atmospheric carbon the 13 c enriched component is less dominant in silicate hosted deposits

environmental changes at final warming of middle pleistocene mis 7 in south kurils abstract entirely new data have been obtained on the south kuril environments at the time of the middle pleistocene warming these data are correlatable with mis 7 the data show climatic rhythms and shed new light on paleo oceanologic conditions and the evolution of environments at that time paleo environmental reconstructions are based on multidisciplinary studies of the marine deposit sequence exposed in a sea cliff in the eastern part of tanfiliev island including a buried oyster reef in the course of the studies analyses of mollusc fauna diatoms and pollen were performed benthic foraminifera were first found in the middle pleistocene sediments of the south kurils the sediments were dated using the 230 th u method and by the presence of the zonal diatom species thalassiosira nidulus the warming process was not unidirectional two warmer intervals were separated by a slight cooling a complicated process of climatic fluctuation is reflected in the succession of diatom assemblages the latter also being influenced by the warm current and the solar heating of coastal water in the first stage of warming there existed an oyster reef composed of densely packed shells of crassostrea gigas nineteen associated species were found 11 percent of them extra limital warm water species the presence of these species suggests the summer surface sea water temperature was 6 c 8 c above that of today on the tanfiliev coast at the time of the reef growth the warming coincided with marine transgression the latter was once interrupted with a limited regression which coincided with a short period of cooling the sequence of deposition environments is reconstructed as follows a shallow bay a coastal lake an open bay the adjacent land was covered with cool temperate broadleaf and coniferous broadleaf forests the coniferous species gaining in importance during cooling during the second warm phase the proportion of coniferous and small leaved species in plant communities was drastically reduced

melt to mush variations in crustal magma properties along the ridge crest at the southern east pacific rise the determination of along axis variations in melt properties within the crustal axial magma chamber beneath fast spreading axes is important for understanding melt delivery from the mantle eruption history along the ridge crest and the process of crustal accretion seismic reflection images1 2 3 4 have shown the molten sill to be continuous along the ridge crest for many tens of kilometres with varying widths 250 4 500 m but variations in its seismic properties and thickness have remained elusive despite several attempts to constrain these properties5 6 7 here we report that the melt sill along the southern east pacific rise which is about 50 m thick undergoes abrupt changes in its internal properties ranging from pure melt to mush the 60 km long ridge crest segment near 14 00 s is characterized by three 2 4 km sections containing pure melt embedded within a magma chamber rich in mush these small pure melt pockets may represent a fresh supply of magma from the mantle capable of erupting and forming the upper crust conversely the 80 90 of the magma chamber which is mushy is unlikely to erupt and may influence the lower crustal accretion

spatial distribution and temporal evolution of crustal melt distribution beneath the east pacific rise at 9 10 n inferred from 3 d seafloor compliance modeling determining the melt distribution in oceanic crust at mid ocean ridges is critical to understanding how magma is transported and emplaced in the crust seafloor compliance deformation under ocean wave forcing is primarily sensitive to regions of low shear velocity in the crust making it a useful tool to probe melt distribution analysis of compliance data collected at east pacific rise between 9 and 10 n through 3 d numerical modeling reveals strong along axis variations in the lower crustal shear velocities as well as temporal variation of crustal shear velocity near 9 48 n between measurements spanning 8 years compliance measured across the rise axis at 9 48 n and 9 33 n suggest a deep crustal low velocity zone beneath the ridge axis with a low vs vp ratio consistent with melt in low aspect ratio cracks or sills changes in compliance measured at 9 48 n between years 1999 and 2007 suggest that the melt fraction in the axial crust decreased during this interval perhaps following the 2005 2006 seafloor eruption this temporal variability provides direct evidence for short term variations of the magmatic system at a fast spreading ridge

paleoenvironments and landscape history of the minor kuril islands since the late glacial abstract the problems of vegetation development of the minor kuriles since the last glacial maximum are discussed the size of island land and relief features influenced landscape development under post glacial holocene climatic changes and sea level oscillations the results suggest that isolation had a great role on development of the landscapes low flat relief active wetlands and the cooling influence of the ocean were the main factors in the development of grassland and wetland landscapes on small islands in the late holocene forest vegetation was preserved only on shikotan island which has upland relief the appearance of broad leaved genera and the disappearance of some taxa are discussed

millennial scale variability of holocene hydrography in the southwestern okhotsk sea diatom evidence diatom analysis of two submarine cores off eastern hokkaido island northern japan provides insights into the holocene palaeoenvironmental history of the southwestern okhotsk sea diatom flora was

from alpine type sulfides to nonsulfides in the gorno zn project bergamo italy recent exploration of the gorno zn pb ag deposit in northern italy identified 3 3 mt of sulfides at 4 9 zn 1 3 pb and 27 2 g t ag indicated inferred resources and a further mineralized nucleus of mixed sulfides nonsulfides in the val vedra area currently under evaluation the ores are hosted in triassic limestone and shale sulfides sphalerite ag bearing galena minor pyrite and chalcopyrite paragenetically follow mn fe bearing saddle dolomite and sparry calcite the mineral association and the carbon and oxygen isotope ratios of the sparry calcite avg 13c 1 0 0 6 v pdb avg 18o 19 63 1 25 v smow are in agreement with precipitation from hydrothermal fluids in a deep burial setting sulfide emplacement occurred before the alpine orogeny likely during the early middle jurassic in analogy to other alpine type deposits the nonsulfide ore formed at the expense of sulfides and mainly consists of smithsonite hydrozincite hemimorphite and cerussite the c o isotope values of the early generations of zn carbonates are characterized by 18o between 24 1 and 26 8 v smow and 13c ratios between 3 1 and 1 7 v pdb the later generations have lower 18o 21 9 to 23 9 and lower 13c 6 2 to 3 9 these compositions as those measured on cerussite 13c 6 3 and 7 7 18o 14 0 and 15 3 agree with the formation of the nonsulfides in a supergene environment under climatic conditions warmer than today the 18o decrease from early to late generations suggests progressive involvement of meteoric water sourced from higher altitudes these characteristics indicate that the nonsulfides formed during the exhumation of the gorno area from miocene to pliocene

cooling of the lower oceanic crust thermal models of mid ocean ridges that balance the influx of heat from magmatic sources with the removal of heat by conduction and hydrothermal circulation allow quantification of cooling of young oceanic crust these models reproduce key observations relating to crustal accretion and hydrothermal cooling at fast spreading ridges the rate of cooling is constrained both by the bathymetry of ridge axes and by olivine compositions from ophiolite gabbros successful models involve extensive hydrothermal cooling of the lower crust within 20 km of the ridge with 50 70 kw of hydrothermal cooling for every 1 m of ridge axis at crustal ages of 0 1 0 4 ma these timates can be used to refine global models of geochemical and thermal fluxes close to spreading ridges

oxygen isotope fractionation during synthesis of camg carbonate and implications for sedimentary dolomite formation hydrous camg carbonate was synthesized at temperatures of 40 degrees 60 degrees and 80 degrees c in the laboratory this material has very similar mineralogical characteristics to natural disordered dolomite from the coorong region in south australia besides the dolomite variable amounts of amorphous carbonate are present in all samples the oxygen isotope compositions of synthesized bulk carbonate samples e g amorphous carbonate plus dolomite plot significantly lower than the northrop and clayton 1966 dolomite water equilibrium fractionated degassing of the samples however revealed relatively low oxygen isotope values for fast reacting using 100 h3po4 amorphous carbonate in contrast slow reacting dolomite has more positive oxygen isotope values and calculated carbonate water oxygen isotope fractionation values are close to strongest known dolomite water oxygen isotope fractionation published earlier on variations of reaction stabilization temperatures during synthesis gave evidence for dolomite formation from hypersaline solutions by a dissolution reprecipitation process it is likely that amorphous carbonate has been a problem in defining the dolomite water fractionation in the past moreover dolomite associated amorphous carbonate contents probably led to incorrect speculations about lower oxygen isotope fractionation in a so called protodolomite water system copyright c 2005 elsevier ltd

on the compliance method and the assessment of three dimensional seafloor gas hydrate deposits summary marine gas hydrates prevalent in offshore sediments in canada and japan are a possible hydrocarbon resource a hazard to drilling and the source of a major greenhouse gas quantitative estimates of hydrate concentrations in deep sea sediment are difficult to obtain by conventional methods our group has sought novel techniques specifically designed for assessment such as the compliance method where ocean surface gravity waves are used as a source compliance is the transfer function between the vertical displacement of the seafloor and the corresponding pressure expressed as a function of wavelength it is sensitive to the elastic parameters of the underlying sediments particularly the shear modulus which is probably increased in zones containing hydrate due to cementation our group has demonstrated a connection between a compliance measurement and the amount of hydrate present in the hydrate stability zone for layered models here we develop a 3 d numerical finite difference code using control volume discretization to predict the compliance response over non layered structures among the features of the algorithm are an ability to handle sharp contrasts in elastic moduli with a low usage of computer memory the compliance anomaly over such structures has a signature and resolution not unlike the corresponding gravity anomaly the average response over heterogeneous structures is sensitive to the bulk hydrate content but not the connectivity pattern gravity waves with different polarizations crossing markedly anisotropic structures produce statistically the same average stiffness value

shear wave structure from joint analysis of seismic and seafloor compliance data summary determining shear wave structure is the key to identifying the amount and location of fluid within the crust seismic and seafloor compliance methods provide independent estimates of shear wave structure and a joint analysis of the two data sets should provide better constraints on the properties of the uppermost oceanic crust we consider an example from 9 33 n on the east pacific rise seismic data from an on axis expanding spread profile have been reanalysed to determine a shear wave structure for layer 2b ps arrivals require a high shear wave velocity within this layer poisson ratio in the range 0 22 0 25 compliance data from the same location are seemingly inconsistent with this result requiring that layer 2b is a region of low shear wave velocity poisson ratio in the range 0 33 0 44 the quantitative differences between the two results can be explained by anelasticity and anisotropy conversely a knowledge of this discrepancy can be used to constrain the attenuation structure

extreme silicon isotope fractionation due to si organic complexation implications for silica biomineralization abstract a combination of theoretical predictions and isotopic equilibration experiments using the three isotope method have been performed to assess si isotope fractionation among minerals and aqueous species in the presence of dissolved catechol aqueous si in abiotic ambient temperature aqueous solutions is dominated by the iv coordinated h4sio 4 0 species but the presence of aqueous catechol provokes the formation of a vi fold si catechol complex results show an equilibrium si fractionation factor of 19 between the vi fold coordinated si catechol complex and the iv fold coordinated aqueous silicic acid an amplitude never previously observed for silicon the fractionation between v fold si organo complexes with diolate glyconate or methyllactate groups and silicic acid has also been estimated through theoretical predictions to be about 10 these extreme fractionations can be used to improve our ability to interpret the si isotope compositions of natural solids and in particular those associated with marine silica biomineralization processes e g sponge spicules

multiproxy record of late holocene climatic changes and natural hazards from paleolake deposits of urup island kuril islands north western pacific abstract the evolution of the late holocene environments has been reconstructed on the basis of multiproxy studies of peat sequences the vegetation response to short period climate fluctuations has been traced early in the late holocene there were birch forests with oak and other broadleaf trees vast areas were occupied by forb meadows under cooling 3250 yr bp the shrub pine pinus pumila became the landscape forming species and since 2490 yr bp selaginella selaginoides appeared in abundance the little ice age was marked by the disappearance of broadleaf trees and widely spread heath land communities the higher stands of the lake level were related to warmings 3660 3590 3450 3180 2960 2840 2410 2260 cal yr bp shallowing coincided with short term coolings 3590 3450 3180 2960 2840 2410 2260 2150 cal yr bp marked by reduced precipitations the dune ridge formation began during the longest cooling accompanied by a minor regression the dunes were stabilized and a paleosol developed 2340 2260 yr bp a younger generation of eolian sands developed during the little ice age an ecological effect of volcanic ashfalls has been estimated the local biotic components seem to have been most afflicted by the eruption in the north of iturup in 2100 2300 cal yr bp when ckr tephra up to 30 cm thick was deposited the ages of 4 strongest tsunamis that occurred over the last 3660 years were determined they appeared to be related to the earthquakes with focuses close to urup island or south of it the lake microflora shows ecological effect of the marine water invasions

holocene climatic changes and environmental history of iturup island kurile islands northwestern pacific the study of holocene deposits on iturup island is very important for understanding palaeolandscape changes on the island it is separated by deep straits from the neighbouring islands and was isolated during the last glacial maximum landscape changes over the last 40000 years and the role of refugia on vegetation development are discussed changes in natural processes in this region were controlled both by global climatic changes and by regional factors birch forests developed at the warming about 36 37 ka ago whereas tundrapark landscape developed with the cooling of the last glacial maximum holocene environments reflect climatic changes and sea level oscillations the fluctuation of warm and cold currents influenced the landscape development at the holocene optimum about 6 ka broadleaved forests with quercus phellodendron carpinus juglans fagus fraxinus and syinga occupied the okhotsk side of central iturup climate was warmer than present and the sum of active tempe ratures 10 c was n

oxygen isotope fractionation between calcite and fluid as a function of growth rate and temperature an in situ study the 18o content of carbonates expressed as 18o is widely used in paleothermometry yet it is clear from comparison of experimental results and natural carbonate samples that chemical isotopic equilibrium is not always achieved in nature this observation underscores the importance of exploring possible effects of growth rate on isotopic fractionation which is the focus of this study in situ secondary ion mass spectrometry sims analyses of 18o were performed on single crystals of experimentally grown calcite the change in growth rate v over time within each crystal was monitored by addition of multiple rare earth element ree spikes into the fluid from which the calcite grew the values of 18o in bulk calcites and experimental fluids were measured by stable isotope ratio mass spectrometers the average sims 18o overlaps with those determined by conventional mass spectrometry within analytical uncertainty the fractionation factor expressed as 18o approaches its equilibrium value in slowly grown calcites v 0 02 nm s and decreases by 1 5 with increasing growth rate from 10 3 to 0 34 nm s here 18o 103 ln 18o and 18o 18o 16o calcite 18o 16o fluid our results provide the first in situ evidence that under equilibrium conditions 18o may be depleted in the near surface region of calcite relative to the bulk crystal lattice and that this 18o depleted zone can be captured during rapid crystal growth crystal growth rate is therefore a potentially important consideration when using 18o in natural carbonates as a proxy for ocean and terrestrial temperature