coastal ice core record of recent northwest greenland temperature and sea ice concentration coastal ice cores provide an opportunity to investigate regional climate and sea ice variability in the past to complement hemispheric scale climate reconstructions from ice sheet interior ice cores here we describe robust proxies of baffin bay temperature and sea ice concentration from the coastal 2barrel ice core collected in the thule region of northwest greenland over the 1990 2010 record 2barrel annually averaged methanesulfonic acid msa concentrations are significantly correlated with may june baffin bay sea ice concentrations and summer temperatures higher msa is observed during warmer years with less sea ice indicative of enhanced primary productivity in baffin bay similarly 2barrel annually averaged deuterium excess d excess values are significantly correlated with annual baffin bay sea ice concentrations and summer and annual temperatures warm cool years with anomalously low high sea ice concentration are associated with proportionally more less low d excess baffin bay moisture at the ice core site multilinear regression models incorporating 2barrel msa d excess and snow accumulation account for 38 51 of the baffin bay sea ice and temperature variance the annual temperature model is significantly correlated with temperatures throughout most of greenland and eastern arctic canada due to the strong influence of the north atlantic oscillation and atlantic multidecadal oscillation

characteristic patterns of variability of sea level pressure in the northern hemisphere abstract seasonal and annual mean sea level pressures for the northern hemisphere have been analyzed to determine the dominant modes of interannual and longer period variability using monthly sea level pressure analyses as revised by trenberth and paolino 1980 empirical orthogonal function eof analysis is used to reveal the modes which explain most of the variance for the period 1925 77 in winter kutzbach s 1970 eof 1 for january remains the dominant mode and a closely related pattern dominates all seasons and the annual means although there are differences in detail in each season the dominant mode is basically a high latitude zonal index type pattern with departures in pressure at high latitudes corresponding to anomalies of opposite sign in low latitudes eof 1 is linked to the north atlantic oscillation but the north south fluctuations in mass also occur in the pacific and to a lesser extent elsewhere time series associated with this pattern have highly significant spectral peaks at the

mount logan ice core record of tropical and solar influences on aleutian low variability 500 1998 a d continuous high resolution paleoclimate records from the north pacific region spanning the past 1500 years are rare and the behavior of the aleutian low alow pressure center the dominant climatological feature in the gulf of alaska remains poorly constrained here we present a continuous 1500 year long calibrated proxy record for the strength of the wintertime december march alow from the mount logan summit pr col 5200 m asl ice core soluble sodium time series we show that ice core sodium concentrations are statistically correlated with north pacific sea level pressure and zonal wind speed our alow proxy record reveals a weak alow from circa 900 1300 a d and 1575 1675 a d and a comparatively stronger alow from circa 500 900 a d 1300 1575 a d and 1675 a d to present the mount logan alow proxy record shows strong similarities with tropical paleoclimate proxy records sensitive to the el nino southern oscillation and is consistent with the hypothesis that the medieval climate anomaly was characterized by more persistent la nina like conditions while the little ice age was characterized by at least two intervals of more persistent el nino like conditions the mount logan alow proxy record is significantly p 0 05 correlated and coherent with solar irradiance proxy records over various time scales with stronger solar irradiance generally associated with a weaker alow and la nina like tropical conditions however a step like increase in alow strength during the dalton solar minimum circa 1820 is associated with enhanced walker circulation furthermore rising co2 forcing or internal variability may be masking the twentieth century rise in solar irradiance

a major holocene enso anomaly during the medieval period 1 here we present a high resolution marine el nino flood record from peru a period of extreme drought without strong flooding occurred from a d 800 1250 anomalous precipitation patterns characterized the entire indo pacific enso domain with dry events in the northern arabian sea and the mid latitudes of both americas coinciding with wet periods in the atlantic cariaco basin the occurrence of contemporaneous moisture anomalies in other archives in the enso region highlights the role of el nino strength in global climate evolution during the late medieval period when temperature reconstructions show a rather heterogeneous pattern

sediment provenance changes in the western arctic ocean in response to ice rafting sea level and oceanic circulation variations since the last deglaciation two sediment piston cores were recovered from the chukchi alaskan 05jpc and canadian beaufort 02pc margins to investigate grain size geochemical and mineralogical compositions this allowed the reconstruction of changes in detrital sediment provenance and transport related to climate variability since the last deglaciation the end member modeling analyses of grain size indicate that sea ice and nepheloid transport and the mackenzie river sediment plume are major factors influencing sedimentation in the chukchi alaskan and canadian beaufort margins respectively unmixing of the sediment composition indicates that detrital sediments in core 02pc are derived mainly from the mackenzie river whereas sediments from core 05jpc are derived mainly from the mackenzie river during the deglaciation and include a mixture of holocene sediments from the bering strait mackenzie river and eurasian margin the dolomite rich ice rafted debris recorded in both cores could be related to the different phases of iceberg discharges from the amundsen gulf ice stream quartz and feldspar rich ice rafted debris dated at 13 and 10 6 ka cal bp before present are related to the lake agassiz outburst in core 02pc and meltwater discharge from the brooks range glaciers in core 05jpc detrital proxies in core 02pc support the hypothesis that large meltwater and iceberg discharges from the lake agassiz outburst to the arctic ocean and amundsen gulf ice stream may have triggered the younger dryas finally similar trends observed between sea level curves and our detrital proxy suggest that the sea level changes in the western arctic ocean have an important influence on the sediment dynamic during the early to middle holocene keywords bulk and clay mineralogy elemental geochemistry grain size distribution sediment provenance canadian beaufort sea chukchi sea

cryogenic brines as diagenetic fluids reconstructing the diagenetic history of the victoria land basin using clumped isotopes abstract the isotopic analyses 13c 18o and 47 of carbonate phases recovered from a core in mcmurdo sound by antarctic geologic drilling andrill 2a indicate that the majority of secondary carbonate mineral formation occurred at cooler temperatures than the modern burial temperature and in the presence of fluids with 18owater values ranging between 11 and 6 vsmow these fluids are interpreted as being derived from a cryogenic brine formed during the freezing of seawater the 47 values were converted to temperature using an in house calibration presented in this paper measurements of the 47 values in the cements indicate increasingly warmer crystallization temperatures with depth and while roughly parallel to the observed geothermal gradient consistently translate to temperatures that are cooler than the current burial temperature the difference in temperature suggests that cements formed when they were 260 100 m shallower than at the present day this depth range corresponds to a period of minimal sediment accumulation from 3 to 11 myr it is therefore interpreted that the majority of cements formed during this time this behavior is also predicted by time integrated modeling of cementation at this site if this cementation had occurred in the presence of these fluids then the cryogenic brines have been a longstanding feature in the victoria land basin brines such as those found at this site have been described in numerous modern high latitude settings and analogous fluids could have played a role in the diagenetic history of other ice proximal sediments and basins during glacial intervals throughout geologic history the agreement between the calculated 18owater value and the measured values in the pore fluids shows how the 47 proxy can be used to identify the origin of negative 18o values in carbonate rocks and that extremely negative values do not necessarily need to be a result of the influence of meteoric fluids or reaction at high temperature

postglacial vegetation and fire history eastern klamath mountains california usa pollen and high resolution charcoal data from bluff lake and crater lake california indicate simi lar changes in climate vegetation and fire history during the last 15 500 years pollen data at bluff lake suggest that the vegetation between c 15 500 and 13 100 cal bp consisted of subalpine parkland with scattered pinus and abies after 13 100 cal bp a relatively closed forest of p monticola p contorta and abies developed and fire event frequency was low the inferred climate then was cooler and wetter than present pinus and quercus vaccinifoliadominated at both sites during the early holocene when conditions were warm and dry as climate became wetter and cooler in the late holocene abies spp at both sites and tsuga mertensi ana at crater lake increased in importance displacing pinus and quercus the two lake records have similar trends in fire history with high event frequencies at c 8400 4000 and 1000 cal bp and low values at c 4800 cal bp the fire and vegetation history at both sites suggests a similar response to large scale changes in climate during the holocene

persistent solar influence on north atlantic climate during the holocene surface winds and surface ocean hydrography in the subpolar north atlantic appear to have been influenced by variations in solar output through the entire holocene the evidence comes from a close correlation between inferred changes in production rates of the cosmogenic nuclides carbon 14 and beryllium 10 and centennial to millennial time scale changes in proxies of drift ice measured in deep sea sediment cores a solar forcing mechanism therefore may underlie at least the holocene segment of the north atlantic9s 1500 year cycle the surface hydrographic changes may have affected production of north atlantic deep water potentially providing an additional mechanism for amplifying the solar signals and transmitting them globally

a 13 000 year climate record from western tibet although the tibetan plateau is important in influencing the atmospheric circulation of the northern hemisphere1 3 there are only a few continuous palaeoclimate records available and these are limited to the plateau s northeastern margin4 6 here we present a 13 000 yr record from sumxi co western tibet constructed from both lake core and shoreline studies which shows that conditions in the early middle holocene were warmer and wetter than at present these results confirm model predictions of an intensified monsoon over the region at 9 000 yr bp owing to an orbitally induced increase in summer insolation7 8 we also find evidence for warm humid pulses at 12 500 and 10 000 yr bp in phase with the steps of the last deglaciation and for a return to cold dry conditions at 11 10 000 yr bp none of which can be explained by orbital variations the existence of the cold episode confirms that the cooling associated with the younger dry as event occurred in continental china6 9 and provides further evidence of the global nature of this event10

ice core record of rising lead pollution in the north pacific atmosphere 1 a high resolution 8000 year long ice core record from the mt logan summit plateau 5300 m asl reveals the initiation of trans pacific lead pb pollution by ca 1730 and a 10 fold increase in pb concentration 1981 1998 mean 68 9 ng l above natural background 5 6 ng l attributed to rising anthropogenic pb emissions from asia the largest rise in north pacific pb pollution from 1970 1998 end of record is contemporaneous with a decrease in eurasian and north american pb pollution as documented in ice core records from greenland devon island and the european alps the distinct pb pollution history in the north pacific is interpreted to result from the later industrialization and less stringent abatement measures in asia compared to north america and eurasia the mt logan record shows evidence for both a rising pb emissions signal from asia and a trans pacific transport efficiency signal related to the strength of the aleutian low

glaciochemistry of polar ice cores a review human activities have already modified the chemical composition of the natural atmosphere even in very remote regions of the world the study of chemical parameters stored in solid precipitation and accumulated on polar ice sheets over the last several hundred thousand years provides a unique tool for obtaining information on the composition of the preindustrial atmosphere and its natural variability over the past this paper deals with the chemistry of polar ice focused on the soluble mineral na nh4 k ca mg h f cl no3 so4 and h2o2 and organic methanesulfonate ch3so3 formate hcoo acetate ch3coo and formaldehyde hcho species and their interpretation in terms of past atmospheric composition aerosols and water soluble gaseous species we discuss ice core dating the difficulties connected with trace measurements and the significance of the ionic composition of snow we examine temporal from the last decades back to the last climatic cycle and spatial including examples from coastal as well as central areas of greenland and antarctica variations in the ionic budget of the precipitation and evaluate ice core studies in terms of the chemical composition of our past atmosphere we review 1 how greenland and antarctic ice cores that span the last few centuries have provided information on the impact of human activities and 2 how the chemistry of deep ice cores provides information on various past natural phenomena such as climatic variations glacial interglacial changes el nino volcanic eruptions and large boreal forest fires

fault controlled and stratabound dolostones in the late aptian earliest albian benassal formation maestrat basin e spain petrology and geochemistry constrains this study was developed under the exxonmobil fc2 alliance fundamental controls on flow in carbonates the authors wish to thank exxonmobil production company and exxonmobil upstream research company for providing funding the views in this article by sherry l stafford are her own and not necessarily those of exxonmobil this research was supported by the sedimentary geology research group of the generalitat de catalunya 2014sgr251 we would like to thank andrea ceriani and paola ronchi for their critical and valuable reviews and associated editor piero gianolla for the editorial work

formation of lateral patterns in rock properties by dolomitization evidence from a miocene reaction front bonaire netherlands antilles abstract petrophysical and geochemical properties of dolomites may exhibit a nested set of lateral patterns typically at the scales of a few meters to 20 m this study assesses whether those lateral patterns are inherited from the limestone precursor or formed during dolomitization sampling was done across a preserved limestone to dolomite reaction front in grainstones of the miocene seroe domi formation bonaire netherlands antilles post dolomitization diagenetic overprinting in the two rock types is absent or minimal two 65 m lateral transects were drilled at 30 cm spacing in two separate beds porosity permeability and geochemical 18o 13c mn sr and na analyses were performed on all 287 recovered samples and 287 thin sections were point counted for petrographic attributes variography shows that dolomite abundance and porosity contain three scales of lateral variability much of the signal is random sample to sample noise as 65 of the total spatial variance occurs at 30 cm spacing however porosity and dolomite abundance also exhibit a short scale correlation length of 3 7 m and a long range oscillatory pattern hole effect at 16 m both of which are also periodic trace elements mn sr and permeability exhibit short range correlation to 5 8 m but no long range pattern mole mg and 13c show increasing variance with distance and all other dolomite attributes exhibit no spatial patterns no limestone attributes show evidence for any short range or long range oscillatory patterns this indicates that the lateral patterns in dolomite abundance porosity permeability sr and mn contents were not inherited from the limestone precursor dolomitization is interpreted to be the cause of the observed spatial patterns as that is the only geologic process that has affected the dolomite but not the limestone on the other side of the front geochemical self organization during the dolomitization process is suggested to be the mechanism by which the spatial patterns in the dolomites emerge a model for that self organizing process is proposed that involves positive feedbacks between precipitation dissolution textural properties reaction rates carbon transport and the evolving flow field relative to mississippian permian and eocene dolomites that have been studied previously the seroe domi dolomites have similar porosity variance at 30 cm spacing and hole effects with slightly greater wavelengths and much larger magnitudes any differences are interpreted to be related to diagenetic history the older dolomites have been affected by burial diagenesis and or weathering which would likely increase sample to sample variability therefore increasing short scale randomness decreasing the magnitude of hole effects and shortening wavelengths of hole effects the lateral patterning formed by dolomitization may thus not be as strongly expressed in ancient dolomites that have complex burial histories

orogenic pulses in the alberta rocky mountains radiometric dating of major faults and comparison with the regional tectono stratigraphic record radiometric ages from regionally distributed thrust fault gouge show that the eastward propagation of the southern rocky mountain fold and thrust belt in canada occurred in four orogenic pulses that correlate with tectonic events of the cordilleran interior and with depositional patterns in the adjacent foreland in the main ranges the pyramid 163 0 ma simpson pass 161 7 ma and johnson creek 145 7 ma thrusts were related to the initiation of thin skinned deformation from jurassic terrane accretion and were partly contemporaneous with development of the first clastic wedge in the foreland basin in the front ranges the emplacement of the greenock thrust 103 1 ma and broadview snake indian thrust 99 2 ma was contemporaneous with development of cenomanian deltaic deposits in the immediate foreland three thrusts in the front ranges rocky pass 74 8 ma sulfur mountain 75 6 ma and clearwater 74 2 ma thrusts define a campanian phase of tectonic loading that led to the last major transgression in the southern portion of the alberta foreland along the eastern margin of the front ranges the mcconnell thrust 54 0 ma together with the muskeg 52 4 ma brule 53 9 ma and nikanassin 52 1 ma thrusts in the foothills recorded the last phase of regional contraction the late jurassic mid cretaceous late cretaceous and early eocene deformation pulses are separated by relatively long periods 40 m y 20 m y and 10 m y of tectonic quiescence these spatially and temporally restricted fault motion pulses contrast with gradual forward fault propagation while regional eastward progression of deformation is preserved

automated mineralogical methodology to study carbonate grain microstructure an example from oncoids oncoids collected from an arid intertidal embayment of the gulf of aqaba saudi arabia were examined for their morphology and mineralogical composition this study tested a methodological approach for studying oncoid microstructure and chemical mineralogical composition in detail the method was applied to more than 30 oncoid samples and examined internal morphology and composition via automated mineralogy and petrographic methods deploying quantitative evaluation of minerals by scanning electron microscopy qemscan the qemscan analysis system gathers x ray and backscattered electron data from predefined points on a sample and interprets it in mineralogical terms by comparisons with a spectral library volumetric modal analysis a function of the cumulative data obtained is then used to quantify the mineral species present in the sample the most abundant minerals in this study consist of calcium carbonate 60 70 quartz dominates the detrital trapped grains 19 5 potassium feldspar and albite constitute 5 6 and 3 4 respectively minerals such as illite chlorite biotite muscovite smectite kaolinite apatite and ilmenite and siderite individually make up less than 1 of the overall oncoid composition unlike traditional light microscope petrography x ray fluorescence and x ray diffraction methods the proposed technique has several advantages including but not limited to preservation of the oncoid microstructure porosity and pore size estimation elemental distribution of major minerals determination of the chemical composition of grains as well as the cement and relatively high accuracy of elemental compositional data taken from polished sections this study shows that qemscan can provide an effective and robust tool in analyzing different components of oncoids and other carbonate grains

imprint of large scale atmospheric transport patterns on sea salt records in northern greenland ice cores the decadal to interannual variability of sea salt aerosol concentrations in northern greenland ice cores is investigated and contrasted to meteorological reanalysis data over the time span 1959 1993 correlation analysis with average data on sea level pressure and geopotential height at the 500 mbar level identifies the eastern and northeastern pacific region as the most important center of action responsible for variations in sea salt aerosol export onto the greenland ice sheet which is related to the pacific north american teleconnection pattern the atlantic region however appears to be of secondary importance only correlation coefficients are highest during the first quarter of the year but also significant for annual pressure data explaining 20 of the sea salt variance in the ice cores furthermore higher storm activity in the pacific center of action as well as in the northern atlantic leads to higher sea salt concentrations in northern greenland explaining about 40 and 17 of the ice core variance a 30 increase during the nineteenth century in a 600 year sea salt record from northeastern greenland may be interpreted at least in part as an enhancement of sea salt export from the pacific region during that time

in situ characterization of dolomite crystals evaluation of dolomitization process and its effect on zoning dolomitization is a dissolution re precipitation process which proceeds via micrometre scale interface reaction horizons however the effect of this fundamental local medium of replacement process on precipitated dolomite crystals is rarely investigated for this purpose dolomite samples of ordovician boat harbour formation carbonates newfoundland canada from main brook and daniel s harbour about 150 km apart were studied the investigation used high resolution approaches to carry out imaging and elemental analyses of individual dolomite crystals including scanning electron microscopy scanning electron microscopy based cathodoluminescence secondary ion mass spectrometry and electron microprobe analysis the purpose was to better understand geochemical variations across the crystal traverses and their association with dolomite replacement processes and conditions the scanning electron microscopy based cathodoluminescence zoning character reveals three major crystal facies distinctly planar boundaries zoned core and indistinctly zoned core are zoned dolomite crystal facies in burial dolomite from main brook relatively unzoned crystal facies was identified in that of daniel s harbour compositionally zoned dolomite crystals are characterized by decreasing sr na y and ree but increasing mn and fe from core to rim sections core to rim zoning was not found for major mg and ca elements the zoning exhibited by the replacive dolomite crystals is interpreted to be principally a result of limited exchange between solutes of the bulk pore fluid and those of dissolving precursor marine carbonate in tandem with petrographic features the systematic compositional zoning character demonstrates that the effectiveness of the dolomitization process grades from indistinctly zoned core to relatively unzoned crystal facies via interface reaction horizons homogenization of major elements of core and rim sections seen in distinctly zoned core crystal facies and to a much greater extent in relatively unzoned crystal facies via a secondary reaction interface is the first recognized stage of the maturation process followed by homogenization of the trace elements seen largely in relatively unzoned crystal facies

evaluating new fault controlled hydrothermal dolomitization models insights from the cambrian dolomite western canadian sedimentary basin fault controlled hydrothermal dolomitisation in tectonically complex basins can occur at any depth and from different fluid compositions including deep seated crustal or basinal brines nevertheless many studies have failed to identify the actual source of these fluids resulting in a gap in our knowledge on the likely source of magnesium of hydrothermal dolomitisation with development of new concepts in hydrothermal dolomitisation the study aims in particular to test the hypothesis that dolomitising fluids were sourced from either seawater ultramafic carbonation or a mixture between the two by utilising the cambrian mount whyte formation as an example here the large scale dolostone bodies are fabric destructive with a range of crystal fabrics including euhedral replacement rd1 and anhedral replacement rd2 since dolomite is cross cut by low amplitude stylolites dolomitisation is interpreted to have occurred shortly after deposition at a very shallow depth 1 km at this time there would have been sufficient porosity in the mudstones for extensive dolomitisation to occur and the necessary high heat flows and faulting associated with cambrian rifting to transfer hot brines into the near surface while the 18owater and 87sr 86sr ratios values of rd1 are comparable with cambrian seawater rd2 shows higher values in both parameters therefore although aspects of the fluid geochemistry are consistent with dolomitisation from seawater very high fluid temperature and salinity could be suggestive of mixing with another hydrothermal fluid the very hot temperature positive eu anomaly enriched metal concentrations and cogenetic relation with quartz could indicate that hot brines were at least partially sourced from ultramafic rocks potentially as a result of interaction between the underlying proterozoic serpentinites and co2 rich fluids this study highlights that large scale hydrothermal dolostone bodies can form at shallow burial depths via mixing during fluid pulses providing a potential explanation for the mass balance problem often associated with their genesis

moisture dynamics in central asia for the last 15 kyr new evidence from yili valley xinjiang nw china based on high resolution palynological investigations and ams 14 c dating the continuous lacustrine sediments contained in yili valley xinjiang provide an opportunity to reconstruct the effective moisture changes for the last 15 kyr in central asia the relatively warm and humid climate of the bolling allerod 15 12 9 cal kyr bp is a generalization but it seems to show some fluctuations the time of the younger dryas yd interrupted the increasing trend of effective moisture in the study region the climate was cold and relatively dry in the early yd period 12 9 12 0 cal kyr bp whereas the desert vegetation community appeared around 11 8 cal kyr bp almost the driest time since the 15 cal kyr br a sharp increase in effective moisture marked the beginning of the holocene in the yili valley the early holocene 10 6 7 6 cal kyr bp was the wettest time with a developed temperate steppe a dry climate with desert vegetation arose in the early mid holocene 7 6 6 5 cal kyr bp spanning 1100 years a second humid phase emerged between 6 5 and 5 2 cal kyr bp whose vegetation community was represented by temperate steppe moisture was reduced again and the climate became drier between 5 2 and 3 3 cal kyr bp when vegetation was dominated by desert steppe in the yili valley regional comparisons indicate that the moisture changes in yili valley were mainly influenced by the north atlantic ocean ssts through the westerlies the mean position of the siberian high pressure cell probably made a great contribution to the drought between 7 6 and 6 5 cal kyr bp the climate changes were generally consistent between the westerly dominant central asia and asian monsoon regions since the last deglaciation possibly forced by summer insolation conditions in the northern hemisphere c 2011 elsevier ltd all rights reserved

greenland ice core signal characteristics an expanded view of climate change the last millenium of earth history is of particular interest because it documents the environmental complexities of both natural variability and anthropogenic activity we have analyzed the major ions contained in the greenland ice sheet project 2 gisp 2 ice core from the present to 674 a d to yield an environmental reconstruction for this period that includes a description of nitrogen and sulfur cycling volcanic emissions sea salt and terrestrial influences we have adapted and extended mathematical procedures for extracting sporadic e g volcanic events secular trends and periodicities found in the data sets finally by not assuming that periodic components signals were stationary and by utilizing evolutionary spectral analysis we were able to reveal periodic processes in the climate system which change in frequency turn on and turn off with other climate transitions such as that between the little ice age and the medieval warm period

teleconnections in the geopotential height field during the northern hemisphere winter abstract contemporaneous correlations between geopotential heights on a given pressure surface at widely separated points on earth referred to as teleconnections in this paper are studied in an attempt to identify and document recurrent spatial patterns which might be indicative of standing oscillations in the planetary waves during the northern hemisphere winter with time scales on the order of a month or longer a review of existing literature on the subject reveals the existence of at least four such patterns the north atlantic and north pacific oscillations identified by walker and bliss 1932 a zonally symmetric seesaw between sea level pressures in polar and temperature latitudes first noted by lorenz 1951 and what we will refer to as the pacific north american pattern which has been known to operational long range forecasters in this country since the 1950 s a data set consisting of nmc monthly mean sea level pressure and 500 mb height analyses for a 15 year period is used as a basis fo

a reinterpretation of sea salt records in greenland and antarctic ice cores it has recently been shown that much sea salt aerosol around the coast of antarctica is generated not from open water but from the surface of newly formed sea ice previous interpretations of ice core records have disregarded the sea ice surface as a source of sea salt the majority of sea salt aerosol at halley research station originates from frost flowers rather than open water and the seasonal cycle of sea salt in aerosol at halley appears to be controlled by ice production in the weddell sea as well as variations in wind speed frost flowers are also an important source of aerosol at siple dome suggesting that variations in sea salt concentrations in the core and other cores drilled in similar locations may be reflecting changes in sea ice production rather than changes in transportation patterns for greenland cores and those from low accumulation inland sites in antarctica it is not simple to calculate the proportion of sea salt originating from frost flowers rather than open water however modelling studies suggest that a sea ice surface source contributed much of the flux of sea salt to these sites in glacial periods suggesting that interpretations of ice core records from these locations should also be revisited

late paleozoic and mesozoic terrane interactions in north central british columbia five clearly defined terranes comprising from northeast to southwest ancestral north america slide mountain quesnellia cache creek and stikinia are the dominant tectonic elements of north central british columbia stratigraphic sedimentological plutonic metamorphic and structural data show that the slide mountain terrane evolved as a subduction accretion and island arc complex during permian time sedimentological data hint at the demise of the slide mountain and cache creek oceanic environments in the permian or early triassic and late triassic respectively subduction led to the development of volcanic plutonic island arcs on stikinia quesnellia and locally on the cache creek terrane in late triassic to middle jurassic time marked inter and intra terrane contraction in the middle jurassic resulted in the south westward thrusting of the cache creek terrane onto stikinia the subsequent development of the bowser basin on stikinia and possible coeval culmination of the emplacement of que

bipolar changes in atmospheric circulation during the little ice age annually dated ice cores from siple dome west antarctica and central greenland indicate that meridional atmospheric circulation intensity increased in the polar south pacific and north atlantic at the beginning 1400 a d of the most recent holocene rapid climate change event the little ice age lia as deduced from chemical concentrations at these core sites the lia was characterized by substantial meridional circulation strength variability and this variability persists today despite strong evidence for an end to lia cooling thus increased late 20th century storm variability may be in part a result of the continuation of these climatic fluctuations

isoscapes of δ18o and δ2h reveal climatic forcings on alaska and yukon precipitation spatially extensive arctic stable isotope data are sparse inhibiting the climatic understanding required to interpret paleoclimate proxy records to fill this need we constrained the climatic and physiographic controls on 18o and d values of stream waters across alaska and the yukon to derive interpolated isoscape maps 18o is strongly correlated to winter temperature parameters and similarity of the surface water line 2h 8 0 18o 6 4 to the global meteoric water line suggests stream waters are a proxy for meteoric precipitation we observe extreme orographic 18o decreases and a trans alaskan continental gradient of 8 3 1000 km 1 continental gradients are high in coastal zones and low in the interior localized 18o increases indicate inland air mass penetration via topographic lows using observed 18o temperature gradients we show that 18o decreases in a 24 ka permafrost ice wedge relative to the late holocene indicate mean annual and coldest quarter temperature reductions of 8 9 1 7 c and 17 2 3 2 c respectively this article is protected by copyright all rights reserved

reinterpretation of middle cambrian stratigraphy of the rifted western laurentian margin burgess shale formation and contiguous units sauk ii megasequence rocky mountains canada abstract until recently research on the renowned fossil animals of the burgess shale has advanced to a greater degree than an understanding of the rocks in which they are found studies addressing lithostratigraphy and hydrothermal petrography of the so called inner carbonate belt and adjacent chancellor group however have begun to re evaluate long standing hypotheses on the middle cambrian of western canada tectonic activity along the kicking horse rim buried remnants of neoproterozoic rifting during the cambrian period had more influence on local sedimentation than previously thought notably large scale collapse of the cathedral carbonate platform margin at 509 ma bp is evidence of reactivated basement faults these failures produced listric megatruncation surfaces having near vertical escarpments 150 m in height where they terminate against the platform the majority of what have been interpreted as shed olistoliths from the cathedral platform margin is herein shown instead to be carbonate mud mounds these grew in situ along the face of the cathedral escarpment and are associated with fossiliferous intervals in overlying basinal mudstones at three distinct stratigraphic horizons two within the burgess shale during the delamaran and marjuman stages the mounds nucleated where deep seated normal faults intersected the seafloor building primarily during periods of relative sea level transgression mound growth is associated with syndepositional exhalative activity inferred from stratigraphic relations sedimentology and geochemistry the new name monarch formation is proposed for the initial post collapse beds and mounds deposited against the cathedral escarpment early glossopleura zone the variably defined term takakkaw tongue is thereby confined to pre collapse slope deposits coeval to and correlative with the cathedral formation

reservoir quality textural evolution and origin of fault associated dolomites fault associated dolomitized carbonates are proven hydrocarbon reservoirs in the subsurface yet their origins and spatial variability in reservoir quality are poorly understood fault associated dolomitization has affected a 4 8 km 2 5 5 mi wide strip of inner platform carbonates of the oligocene miocene taballar limestone exposed onshore northeastern borneo where they are juxtaposed against deep marine shales of the eocene maliu mudstone on textural grounds planar dolomites postdating compaction and from the predominance of monophase aqueous inclusions replacive dolomite rhombs and later dolomite cements appear to have formed at about 50 60c and at shallow burial depths up to 0 5 1 km 0 3 0 6 mi isotopic and inclusion data indicate that the most likely dolomitizing fluid was dominated by neogene seawater for dolomites 18ov pdb 5 9 to 10 3 consistent with the precipitation from southeast asian oligocene miocene seawater 18o 1 5 to 4 2 at temperatures of 40c up to a maximum of about 50 75c 87sr 86sr 0 708566 0 708697 from tm 2 1 3 4 wt nacl however replacement and remobilization of the precursor limestone also contributed to the isotopic signature of the dolomites 87sr 86sr 0 708115 0 708197 whereas an evolved formation water component cannot be ruled out dolomitizing fluids used faults and fractures as conduits to move into and alter the limestone migrating farthest into the most permeable strata the likely driver for fluid movement was convective flow caused by nearby neogene igneous activity perhaps in combination with tectonically induced hydrologic drive related to fault reactivation close to the main fault late stage dolomite cements occlude pore throats reducing porosity 5 and permeability 5 md the best reservoir quality occurs in medium to coarsely crystalline idiotopic mosaics of dolomite that have completely replaced the limestone 0 5 2 km 0 3 1 2 mi away from the main fault where the late stage cements did not form these dolomites have 12 20 intercrystalline porosity and moderate to good permeability tens of millidarcys fracturing has had variable impact on reservoir quality where late fractures remained open permeability is enhanced tens to hundreds of millidarcys whereas brecciation and fault gouges result in sealing and reduced permeability the textures reservoir quality characteristics and mechanisms of dolomitization show similarities to the few other detailed studies in the literature this study refines the types of predictive reservoir models used in hydrocarbon exploration for subsurface faulted and dolomitized carbonates and increases the understanding of dolomitizing mechanisms of equatorial carbonates

coupled air sea response to solar forcing in the pacific region during northern winter 1 observations since the middle of the 19th century show that the decadal solar oscillation at its peaks strengthens the major convergence zones in the tropical pacific intertropical convergence zone itcz and south pacific convergence zone spcz during northern winter through an amplifying set of coupled feedbacks a set of processes is described that link solar forcing and its response in the tropical pacific with reductions in precipitation in the northwest united states the process begins with an increase in solar forcing which results in a strengthening of the major convergence zones in the tropical pacific this then increases the precipitation in those regions and increases the southeast trade winds stronger trades increase the upwelling of colder water in the eastern equatorial pacific and extend the cold tongue westward thus reducing precipitation in the western pacific this redistribution of diabatic heating and associated convective heating anomalies thus produces anomalies in the tropical hadley north south and walker east west circulations the former weakens as subsidence in equatorial latitudes is enhanced the latter strengthens and extends westward additionally the resulting anomalous rossby wave response in the atmosphere and consequent positive sea level pressure anomalies in the eastern region of the aleutian low in the north pacific that extends to western north america is associated with reductions of precipitation in the northwest united states the response of the climate system to solar forcing is manifested as a strengthening of the climatological precipitation maxima in the tropics

origin and evolution of fault controlled hydrothermal dolomitization fronts a new insight abstract dolomitization is one of the most significant diagenetic reactions in carbonate systems occurring where limestone caco3 is replaced by dolomite camg co3 2 under a wide range of crystallization temperatures and fluids the processes governing its formation have been well studied but the controls on the position of dolomitization fronts in ancient natural settings particularly in a fault controlled hydrothermal system htd have received remarkably little attention hence the origin and evolution of htd dolomitization fronts in the stratigraphic record remain enigmatic here a new set of mineralogical and geochemical data collected from different transects in a partially dolomitized cambrian carbonate platform in western canada are presented to address this issue systematic patterns of sudden decrease in the magnesium content mol mgco3 and increase in porosity were observed towards the margin of the body furthermore fluid temperatures are cooler and 18 owater values are less positive at the dolomitization front than within the core of the body these changes coincide with a change from poorly ordered planar e dolomite with multiple crystal zonations at the margin to an unzoned well ordered interlocking mosaic of planar s to nonplanar dolomite in the core of the body these phenomena are hypothesized to reflect dynamic self limiting processes in the formation and evolution of htd dolomitization fronts through i plummet of dolomitization potential at the head of dolomitizing fluids due to progressive consumption of magnesium and fluid cooling and ii retreat of dolomitization fronts towards the fluid source during subsequent recrystallization of the dolomite body inboard of the termination once overdolomitization took place this new insight illustrates how dolomitization fronts can record the oldest phase of dolomitization instead of the youngest as is often assumed formation of porosity is interpreted to occur as the result of acidification induced grain leaching during the development of dolomitization fronts this mechanism coupled with retrogradation of dolomitization fronts may help to explain the apparent enhancement of porosity in proximity to dolomitization fronts

southern ocean sea ice extent productivity and iron flux over the past eight glacial cycles sea ice and dust flux increased greatly in the southern ocean during the last glacial period palaeorecords provide contradictory evidence about marine productivity in this region but beyond one glacial cycle data were sparse here we present continuous chemical proxy data spanning the last eight glacial cycles 740 000 years from the dome c antarctic ice core these data constrain winter sea ice extent in the indian ocean southern ocean biogenic productivity and patagonian climatic conditions we found that maximum sea ice extent is closely tied to antarctic temperature on multi millennial timescales but less so on shorter timescales biological dimethylsulphide emissions south of the polar front seem to have changed little with climate suggesting that sulphur compounds were not active in climate regulation we observe large glacial interglacial contrasts in iron deposition which we infer reflects strongly changing patagonian conditions during glacial terminations changes in patagonia apparently preceded sea ice reduction indicating that multiple mechanisms may be responsible for different phases of co2 increase during glacial terminations we observe no changes in internal climatic feedbacks that could have caused the change in amplitude of antarctic temperature variations observed 440 000 years ago

unprecedented recent warming of surface temperatures in the eastern tropical pacific ocean climate variability in the tropical pacific ocean influences climate across much of the planet a diatom based record of sea surface temperatures from el junco lake galapagos reveals that the most recent half century is the warmest 50 year period in the past 1 200 years through its intimate connection with the el nino southern oscillation system climate variability in the tropical pacific ocean influences climate across much of the planet but the history of temperature change in the tropical pacific ocean during recent millennia is poorly known the available annually resolved records1 2 are discontinuous and rarely span more than a few centuries longer records at coarser temporal resolution suggest that significant oceanographic changes observed at multi year to multi century resolution have had important effects on global climate3 4 5 here we use a diatom record from el junco lake galapagos to produce a calibrated continuous record of sea surface temperature in the eastern tropical pacific ocean at subdecadal resolution spanning the past 1 200 years our reconstruction reveals that the most recent 50 years are the warmest 50 year period within the record because our diatom based sea surface temperature index resembles northern hemisphere temperature reconstructions we suggest that with continued anthropogenic warming the eastern tropical pacific ocean may continue to warm

synoptic scale controls on the δ18o in precipitation across beringia oxygen isotope records of precipitation 18oprecip from beringia are thought to reflect synoptic scale circulation changes associated with the aleutian low to delineate the spatial pattern of 18oprecip associated with the two dominant modes of aleutian low circulation we combine modern 18oprecip and deuterium excess data with climate reanalysis and back trajectory modeling aleutian low strength and position are revealed to systematically affect regional moisture source and 18oprecip whereby a strengthened aleutian low causes lower higher 18oprecip in western eastern beringia we compare a new 100 year long 18o record from the aleutian islands with the north pacific index the primary indicator of aleutian low strength and find a significant positive relationship r 0 43 p 0 02 n 28 that tracks late twentieth century change this study demonstrates synoptic scale circulation controls on our isotope record and provides a coherent framework for interpreting existing and emerging paleoisotope data from the region

structurally controlled hydrothermal dolomite reservoir facies an overview structurally controlled hydrothermal dolomite htd reservoir facies and associated productive leached limestones are major hydrocarbon producers in north america and are receiving increased exploration attention globally they include multiple trends in the ordovician locally silurian and devonian of the michigan appalachian and other basins of eastern canada and the united states and in the devonian and mississippian of the western canada sedimentary basin they also occur in jurassic hosts along rifted atlantic margins in the jurassic cretaceous of the arabian gulf region and elsewhere hydrothermal dolomitization is defined as dolomitization occurring under burial conditions commonly at shallow depths by fluids typically very saline with temperature and pressure t and p higher than the ambient t and p of the host formation the latter commonly is limestone proof of a hydrothermal origin for htd reservoir facies requires integration of burial thermal history plots fluid inclusion temperature data and constraints on timing of emplacement hydrothermal dolomite reservoir facies are part of a spectrum of hydrothermal mineral deposits that include sedimentary exhalative lead zinc ore bodies and htd hosted mississippi valley type sulfide deposits all three hydrothermal deposits show a strong structural control by extensional and or strike slip wrench faults with fluid flow typically focused at transtensional and dilational structural sites and in the hanging wall transtensional sags above negative flower structures on wrench faults are favored drilling sites for htd reservoir facies saddle dolomite in both replacive and void filling modes is characteristic of htd facies for many reservoirs matrix replacive dolomite and saddle dolomite appear to have formed near contemporaneously and from the same fluid and temperature conditions the original host facies exerts a major influence on the lateral extent of dolomitization resultant textures pore type and pore volume breccias zebra fabrics shear microfractures and other rock characteristics record short term shear stress and pore fluid pressure transients particularly proximal to active faults high temperature hydrothermal pulses may alter kerogen in host limestones a process designated forced maturation basement highs underlying sandstone and or carbonate aquifers probably overpressured and overlying and internal shale seals and aquitards also may constrain or influence htd emplacement although many questions and uncertainties remain particularly in terms of mg and brine source and mass balance recognition and active exploration of the htd play continues to expand increasing use of three dimensional seismic imagery and seismic anomaly mapping combined with horizontal drilling oblique to linear trends defined by structural sags helps to reduce risk

synchronization of dissolution and precipitation fronts during infiltration driven replacement in porous rocks coupled dissolution precipitation reactions where two minerals share a common ion occur frequently in geological replacement the reactions are driven by an inflow of precipitating secondary ions and an outflow of dissolved primary ions although crystallization pressure is frequently invoked to explain volume preserving replacement it cannot be operative if the chemical reactions lead to a loss of mineral volume here the host rock that should confine the precipitating mineral is dissolving faster than the grains are growing in this paper we propose two chemical mechanisms by which a rapid dissolution front and a slower precipitation front can be synchronized and volume for volume replacement preserved we analyze these mechanisms within the framework of reactive transport theory and show that morphological features observed in calcite replacement can be correlated with predictions of the models

asian dustfall in the st elias mountains yukon canada in april 2001 a major atmospheric dustfall event occurred in the st elias mountains yukon territory canada field samples were collected and analyzed for particle size mineralogy chemical composition and sr nd and pb isotopes dusts found above 3000 m had their source in the gobi desert region of northern china and inner mongolia and were transported to the yukon following a series of major dust storms that took place in early april dusts found below 3000 m had local yukon or mixed source s the asian dusts had a modal volume diameter of 4 m typical of far traveled mineral aerosols however larger 10 m particles were also found at 5000 m suggesting a very rapid trans pacific transport in the mid troposphere we estimate that the april 2001 event deposited from 5500 to 6335 tons of dust over an area of 21 000 km2 in the southwestern yukon most of which probably fell within a week our findings are consistent with instrumental observations and model simulations of the april 2001 event while the dust cloud was reportedly mixed with volatile pollutants from asia we found no evidence of metal pollution associated with the dustfall in the yukon our findings contribute to clarify the dynamics and the geochemical impact of asian dust long range transport events and to better estimate eolian fluxes of dustborne elements e g fe to the ocean associated with such events they may also assist in identifying past asian dust events in ice cores drilled from the st elias mountains icefields to develop a long term record of their frequency magnitude and source s

the interaction of tectonics climate and eustasy in controlling dolomitization a case study of cenomanian turonian shallow marine carbonates of the iberian basin

seasonal and spatial variations of snow chemistry on mount logan yukon canada three ice cores were recovered on or near mount logan yukon canada at 3017 4135 and 5340 ma s l in 2002 prior to ice core drilling we collected snow pit and shallow core samples from mount logan in 2001 to study seasonal and spatial variations of snow chemistry we dug snow pits at six sites between 2420 and 5340 m a s l before the beginning of the melt season with the exception of a pit at 3180 m a s l where the melt season had just started but had affected only the near surface stratigraphy three of the pits were extended deeper with a shallow core the snow pit and core samples were analyzed for ion chemistry and 18 o a series of depth profiles of ions and 18 o shows spatial variations though characteristic peaks can usually be traced across all the profiles concentrations and deposition fluxes of na and cl which are mainly of sea salt origin decrease with altitude on the other hand deposition fluxes of no 3 so 4 2 ca 2 and nh 4 show a weak positive relationship with elevation below the summit plateau stable isotopes 18 o decrease with altitude with a distinctive jump between 3200 and 4500 m a s l as was reported previously stable isotopes 18 o cl ch 3 so 3 msa na and ca 2 show clear seasonal variations which would enable us to date the cores by annual layer counting

the 1200 year composite ice core record of aleutian low intensification future changes in north pacific wintertime climate will be largely determined by the response of the aleutian low alow pressure system to anthropogenic forcing although the alow has intensified over the twentieth century global climate model projections of future alow variability are equivocal in order to evaluate decadal to centennial alow forcing mechanisms and provide context for the modern intensification here we combine a new denali ice core alaska sea salt sodium record with the mount logan ice core yukon sodium record to develop a composite 1200 year record of alow variability the composite record indicates that the recent secular alow intensification began circa 1741 and is unprecedented in magnitude and duration over the past millennium north pacific ice core snow accumulation and stable isotope records are consistent with this interpretation the alow intensification is associated with warming tropical pacific sea surface temperatures consistent with dynamic theory and instrumental correlations

distribution of porosity and permeability in platform dolomites insight from the permian of west texas saller and henderson 1998 presented an article concerning porosity and permeability variations in two west texas oil fields north riley and south cowden fields these fields occur within dolomitized permian platform carbonates near the basinward shelf edge of the central basin platform a paleogeographic element that influenced permian deposition in west texas their carefully documented study outlines several anomalous aspects concerning porosity distribution they noted in particular that porosity distribution is not strictly facies dependent but that porosity tends to increase in a basinward direction they suggested that porosity developed largely during dolomitization by the action of hypersaline evaporative fluids that flowed downdip in a basinward direction during the permian these brines were generated in restricted shelf interior lagoons and moved downdip parallel with bedding in a shallow reflux type of hydrologic system driven by subsurface fluid density differences in the permian clear fork and grayburg formations as shown here in figure 1 see figure 18 in saller and henderson 1998 figure 1 part a shows the scenario proposed by saller and henderson 1998 for porosity creation dolomitization and dolomite cementation of the permian clear fork and grayburg formations of west texas they suggested that macrodissolution of calcium carbonate occurred contemporaneously with dolomitization and dolomite cementation this process of brine backreaction however would cause a net increase of porosity in the shelf interior the opposite of what is observed part b shows a two stage scenario proposed here to circumvent the problem of limestone macrodissolution by shelf interior brines that must have been initially in approximate bulk equilibrium with calcium carbonate the first stage records dolomitization by replacement of limestone with little macrodissolution in stage two evaporative shelf interior brines may have evolved in equilibrium with dolomite only and became undersaturated with calcite and aragonite reflux migration of these brines downdip may

mineralogy nucleation and growth of dolomite in the laboratory and sedimentary environment a review dolomite camg co3 2 forms in numerous geological settings usually as a diagenetic replacement of limestone and is an important component of petroleum reservoir rocks rocks hosting base metal deposits and fresh water aquifers dolomite is a rhombohedral carbonate with a structure consisting of an ordered arrangement of alternating layers of ca2 and mg2 cations interspersed with co32 anion layers normal to the c axis dolomite has r3 symmetry lower than the caco3 r3 c symmetry of calcite primarily due to ca mg ordering high magnesium calcite also has r3 c symmetry and differs from dolomite in that ca2 and mg2 ions are not ordered high magnesium calcite with near dolomite stoichiometry 50 mol mgco3 has been observed both in nature and in laboratory products and is referred to in the literature as protodolomite or very high magnesium calcite many dolomites display some degree of cation disorder ca2 on mg2 sites and vice versa which is detectable using transmission electron microscopy and x ray diffractometry laboratory syntheses at high temperature and pressure as well as studies of natural dolomites show that factors affecting dolomite ordering stoichiometry nucleation and growth include temperature alkalinity ph concentration of mg and ca mg to ca ratio fluid to rock ratio mineralogy of the carbonate being replaced and surface area available for nucleation in spite of numerous attempts dolomite has not been synthesized in the laboratory under near surface conditions examination of published x ray diffraction data demonstrates that assertions of dolomite synthesis in the laboratory under near ambient conditions by microbial mediation are unsubstantiated these laboratory products show no evidence of cation ordering and appear to be very high magnesium calcite elevated temperature and elevated pressure experiments demonstrate that dolomite nucleation and growth always are preceded by very high magnesium calcite formation it remains to be demonstrated whether microbial mediated growth of very high magnesium calcite in nature provides a precursor to dolomite nucleation and growth analogous to reaction paths in high temperature experiments

connecting the atlantic sector and the north pacific mt logan ice core stable isotope records during the holocene the role of el nino the 18o holocene of the mt logan ice core is very different from those of eastern arctic canada and greenland the large changes seen in logan dwarf even the largest change the cooling event 8200 years ago in the atlantic sector cores large changes in logan s 18o and d are related to the state of el nino as reflected by the quelccaya 18o series it is found that the lagged auto difference series of the ice core records from the agassiz ice cap greenland and the 23 site stack of paleotemperature records of kaufman et al kaufman ds schneider dp mckay np ammann cm bradley rs briffa kr et al 2009 recent warming reverses long term arctic cooling science 325 1236 produce highly significant matches to the mt logan 18o series these correspondences suggest a lag of 1200 years this lag time is what some models of the diffusive great ocean conveyor d goc predict for the average travel time from the north atlantic to the tropical eastern pacific monte carlo testing of the correlation

stratigraphic architecture and fracture controlled dolomitization of the cretaceous khami and bangestan groups an outcrop case study zagros mountains iran this work has been carried out as part of a joint study between norsk hydro now statoil and nioc national iranian oil company

regional atmospheric circulation change in the north pacific during the holocene inferred from lacustrine carbonate oxygen isotopes yukon territory canada analyses of sediment cores from jellybean lake a small evaporation insensitive groundwater fed lake provide a record of changes in north pacific atmospheric circulation for the last 7500 yr at 5 to 30 yr resolution isotope hydrology data from the southern yukon indicate that the oxygen isotope composition of water from jellybean lake reflects the composition of mean annual precipitation 18op recent changes in the 18o of jellybean sedimentary calcite 18oca correspond to changes in the north pacific index npi a measure of the intensity and position of the aleutian low al pressure system this suggests that 18op variability was related to the degree of fractionation during moisture transport from the gulf of alaska across the st elias mountains and that holocene shifts were controlled by the intensity and position of the al following this model between 7500 and 4500 cal yr b p long term trends suggest a predominantly weaker and or westward al between 4500 and 3000 cal yr b p the al shifted eastward or intensified before shifting westward or weakening between 3000 and 2000 cal yr b p rapid shifts eastward and or intensification occurred 1200 and 300 cal yr b p holocene changes in north pacific atmospheric circulation inferred from jellybean lake oxygen isotopes correspond with late holocene glacial advances in the st elias mountains changes in north pacific salmon abundance and shifts in atmospheric circulation over the beaufort sea

direct physical evidence of dolomite recrystallization the possibility of recrystallization is a long standing barrier to deciphering the genetic origin of dolomites there is often uncertainty regarding whether or not characteristics of ancient dolomites are primary or the consequence of later recrystallization unrelated to the original dolomitization event results from 65 new high temperature dolomite synthesis experiments 1 m 1 0 mg ca ratio solutions at 218 c demonstrate dolomite recrystallization affecting stoichiometry cation ordering and nanometre scale surface texture the data support a model of dolomitization that proceeds by a series of four unique phases of replacement and recrystallization which occur by various dissolution precipitation reactions during the first phase induction period no dolomite forms despite favourable conditions the second phase replacement period occurs when ca rich dolomite products with a low degree of cation ordering rapidly replace calcite reactants during the replacement period dolomite stoichiometry and the degree of cation ordering remain constant and all dolomite crystal surfaces are covered by nanometre scale growth mounds the third phase primary recrystallization period which occurs in the experiments between 97 and 100 dolomite is characterized by a reduced replacement rate but concurrent increases in dolomite stoichiometry and cation ordering the end of the primary recrystallization period is marked by dolomite crystal growth surfaces that are covered by flat laterally extensive layers the fourth phase of the reaction secondary recrystallization period occurs when all calcite is consumed and is characterized by stoichiometric dolomite with layers as well as a continued increase in the degree of cation ordering with time inferences of recrystallization in natural dolomite based on cation order or stoichiometry of dolomite usually depend on assumptions about the precursor dolomite subjected to recrystallization if it is assumed that the experimental evidence presented here is applicable to natural low temperature dolomites then the presence of mounds is direct evidence of a lack of recrystallization and the presence of layers is direct evidence of recrystallization

the greenland ice sheet project 2 depth age scale methods and results the greenland ice sheet project 2 gisp2 depth age scale is presented based on a multiparameter continuous count approach to a depth of 2800 m using a systematic combination of parameters that have never been used to this extent before the ice at 2800 m is dated at 110 000 years b p with an estimated error ranging from 1 to 10 in the top 2500 m of the core and averaging 20 between 2500 and 2800 m parameters used to date the core include visual stratigraphy oxygen isotopic ratios of the ice electrical conductivity measurements laser light scattering from dust volcanic signals and major ion chemistry gisp2 ages for major climatic events agree with independent ages based on varve chronologies calibrated radiocarbon dates and other techniques within the combined uncertainties good agreement also is obtained with greenland ice core project ice core dates and with the specmap marine timescale after correlation through the 18 o of o 2 although the core is deformed below 2800 m and the continuity of the record is unclear we attempted to date this section of the core on the basis of the laser light scattering of dust in the ice

a 1400 year high resolution record of atmospheric circulation over the north atlantic and asia major ion series developed from new subannual scale sampling of an ice core from central greenland are calibrated with instrumental series of atmospheric sea level pressure recording major marine icelandic low and terrestrial siberian high atmospheric circulation systems to provide proxy records of atmospheric circulation over the past 1400 years examination of the proxy records reveals major changes in behaviour of these systems c ad 1400 multidecadal and centennial scale periodic components characterization of mean sea level pressure anomaly fields during the little ice age and the mediaeval warm period the potential role of solar forcing coupled ocean atmosphere associations and a perspective within which the characteristics of instrumental era climate can be assessed

enso like interdecadal variability 1900 93 a number of recent studies have reported an enso like eof mode in the global sea surface temperature sst field whose time variability is marked by an abrupt change toward a warmer tropical eastern pacific and a colder extratropical central north pacific in 1976 77 the present study compares this pattern with the structure of the interannual variability associated with the enso cycle and documents its time history back to 1900 the analysis is primarily based on the leading eofs of the sst anomaly and anomaly deviation fields in various domains and the associated expansion coefficient or principal component time series which are used to construct global regression maps of sst sea level pressure slp and a number of related variables the use of anomaly deviations i e departures of local sst anomalies from the concurrent global mean sst anomaly reduces the influence of global mean sst trends upon the structure of the eofs and their expansion coefficient time series an important auxiliary time series used in this study is a southern oscillation index based on marine surface observations by means of several different analysis techniques the time variability of the leading eof of the global sst field is separated into two components one identified with the enso cycle related variability on the interannual timescale and the other a linearly independent residual comprising all the interdecadal variability in the record the two components exhibit rather similar spatial signatures in the global sst slp and wind stress fields the sst signature in the residual variability is less equatorially confined in the eastern pacific and it is relatively more prominent over the extratropical north pacific the corresponding slp signature is also stronger over the extratropical north pacific and its counterpart in the cold season 500 mb height field more closely resembles the pna pattern the amplitude time series of the enso like pattern in the residual variability reflects the above mentioned shift in 1976 77 as well as a number of other prominent features including a shift of opposite polarity during the 1940s

terra rossa genesis implications for karst and eolian dust a geodynamic thread abstract although terra rossa has long been thought to form by residual dissolution of limestone and or by accumulation of detrital mud ash or dust on preexisting karst limestones we present conclusive new field and petrographic evidence that terra rossa forms by replacement of limestone by authigenic clay at a moving metasomatic front several centimeters wide the red clay s major chemical elements al fe and si probably come from dissolved eolian dust the replacement of calcite by clay exhibits a serrated microstylolitic texture that helps prove that replacement happens not by dissolution precipitation as conventional wisdom has it but by pressure solution of calcite driven by the crystallization stress generated by the growth of clay crystals the acid produced by the isovolumetric replacement of limestone by clay quickly dissolves out additional porosity permeability in an adjacent slice of limestone within the front triggering a reactive infiltration instability that should theoretically

atmospheric deposition of glacial iron in the gulf of alaska impacted by the position of the aleutian low our understanding of glacial flour dust storm delivery of iron to the gulf of alaska goa is limited here we interpret concurrent time series satellite meteorological and aerosol geochemical data from the goa to examine how interannual variability in regional weather patterns impacts offshore aerosol glacial fe deposition in 2011 when a northerly aleutian low al was persistent during fall dust emission was suppressed and highly intermittent due to prevalent wet conditions low winds and a deep early season snowpack conversely in 2012 frequent and prolonged fall dust storms and high offshore glacial fe transport were driven by dry conditions and strong offshore winds generated by persistent strong high pressure over the alaskan interior and bering sea and a southerly al twenty five fold interannual variability in regional offshore glacial aerosol fe deposition indicates that glacial dust s impact on goa nutrient budgets is highly dynamic and particularly sensitive to regional climate forcing

the forcing of the pacific decadal oscillation the pacific decadal oscillation pdo defined as the leading empirical orthogonal function of north pacific sea surface temperature anomalies is a widely used index for decadal variability it is shown that the pdo can be recovered from a reconstruction of north pacific sea surface temperature anomalies based on a first order autoregressive model and forcing by variability of the aleutian low el nino southern oscillation enso and oceanic zonal advection anomalies in the kuroshio oyashio extension the latter results from oceanic rossby waves that are forced by north pacific ekman pumping the sst response patterns to these processes are not orthogonal and they determine the spatial characteristics of the pdo the importance of the different forcing processes is frequency dependent at interannual time scales forcing from enso and the aleutian low determines the response in equal parts at decadal time scales zonal advection in the kuroshio oyashio extension enso and anomalies of the aleutian low each account for similar amounts of the pdo variance these results support the hypothesis that the pdo is not a dynamical mode but arises from the superposition of sea surface temperature fluctuations with different dynamical origins

volcanic aerosol records and tephrochronology of the summit greenland ice cores the recently collected greenland ice sheet project 2 gisp2 and greenland ice core project ice cores from summit greenland provide lengthy and highly resolved records of the deposition of both the aerosol h2so4 and silicate tephra components of past volcanism both types of data are very beneficial in developing the hemispheric to global chronology of explosive volcanism and evaluating the entire volcanism climate system the continuous time series of volcanic so42 for the last 110 000 years show a strong relationship between periods of increased volcanism and periods of climatic change the greatest number of volcanic so42 signals many of very high magnitude occur during and after the final stages of deglaciation 6000 17 000 years ago possibly reflecting the increased crustal stresses that occur with changing volumes of continental ice sheets and with the subsequent changes in the volume of water in ocean basins sea level change the increase in the number of volcanic so42 signals at 27 000 36 000 and 79 000 85 000 years ago may be related to initial ice sheet growth prior to the glacial maximum and prior to the beginning of the last period of glaciation respectively a comparison of the electrical conductivity of the gisp2 core with that of the volcanic so42 record for the holocene indicates that only about half of the larger volcanic signals are coincident in the two records other volcanic acids besides h2so4 and other so42 sources can complicate the comparisons although the threshold level picked to make such comparisons is especially critical tephra has been found in both cores with a composition similar to that originating from the vatnaoldur eruption that produced the settlement layer in iceland mid a d 870s from the icelandic eruption that produced the saksunarvatn ash 10 300 years ago and from the icelandic eruption s that produced the z2 ash zone in north atlantic marine cores 52 700 years ago the presence of these layers provides absolute time lines for correlation between the two cores and for correlation with proxy records from marine sediment cores and terrestrial deposits containing these same tephras the presence of both rhyolitic and basaltic shards in the z2 ash in thegisp2 core and the composition of the basaltic grains lend support to multiple icelandic sources torfajokull area and katla for the z2 layer deposition of the z2 layer occurs at the beginning of a stadial event further reflecting the possibility of a volcanic triggering by the effects of changing climatic conditions

holocene climate variability although the dramatic climate disruptions of the last glacial period have received considerable attention relatively little has been directed toward climate variability in the holocene 11 500 cal yr b p to the present examination of similar to50 globally distributed paleoclimate records reveals as many as six periods of significant rapid climate change during the time periods 9000 8000 6000 5000 4200 3800 3500 2500 1200 1000 and 600 150 cal yr b p most of the climate change events in these globally distributed records are characterized by polar cooling tropical aridity and major atmospheric circulation changes although in the most recent interval 600 150 cal yr b p polar cooling was accompanied by increased moisture in some parts of the tropics several intervals coincide with major disruptions of civilization illustrating the human significance of holocene climate variability c 2004 university of washington all rights reserved

holocene glacier activity in the british columbia coast mountains canada abstract the coast mountains flank the pacific ocean in western british columbia canada subdivided into the southern pacific ranges central kitimat ranges and northern boundary ranges the majority of large glaciers and icefields are located in the boundary and pacific ranges prior descriptions of the holocene glacial history of this region indicate the holocene was characterized by repeated episodes of ice expansion and retreat recent site specific investigations augment our understanding of the regional character and duration of these events in this paper previously reported and new radiocarbon evidence is integrated to provide an updated regional assessment the earliest evidence of glacier expansion in the coast mountains comes from the boundary ranges at 8 9 and 7 8 ka and in the pacific ranges at 8 5 8 2 ka with the latter advance corresponding to an interval of rapid global climate deterioration although generally warm and dry climates from 7 3 to 5 3 ka likely limited the size of glaciers in the region there is radiocarbon evidence for advances over the interval from 7 3 to 6 0 and at 5 4 5 3 ka in the pacific ranges following these advances glaciers in the pacific ranges expanded down valley at 4 8 4 6 4 4 4 0 3 5 2 6 1 4 1 2 and 0 8 0 4 ka while glaciers in boundary ranges were advancing at 4 1 4 0 3 7 3 4 3 1 2 8 2 3 1 7 1 1 and 0 8 0 4 ka after 0 4 ka it appears that most glaciers in the coast mountains continued to expand to attain their maximum holocene extents by the early 18th to late 19th centuries this enhanced record of holocene glacier activity highlights the temporal synchrony in the coast mountains individual expansion events in the mid to late holocene broadly correspond to intervals of regional glacier activity reported in the canadian rocky mountains in alaska and on high elevation volcanic peaks in washington state

complexity of holocene climate as reconstructed from a greenland ice core glaciochemical time series developed from summit greenland indicate that the chemical composition of the atmosphere was dynamic during the holocene epoch concentrations of sea salt and terrestrial dusts increased in summit snow during the periods 0 to 600 2400 to 3100 5000 to 6100 7800 to 8800 and more than 11 300 years ago the most recent increase and also the most abrupt coincides with the little ice age these changes imply that either the north polar vortex expanded or the meridional air flow intensified during these periods and that temperatures in the mid to high northern latitudes were potentially the coldest since the younger dryas event

recent retreat of columbia glacier alaska millennial context columbia glacier in prince william sound alaska has retreated 20 km in the past three decades we use marine sediment records to document the columbia glacier advance and retreat history over the past 1 6 k y in an effort to place its recent retreat in the context of the common era c e a change in magnetic mineralogy coincided with a shift in sediment geochemistry ca 0 9 ka this provenance change documents the advance of columbia glacier across a fault resulting in glacial erosion of mafic rocks near the coast this agrees with the timing of ice advance reconstructed using dendrochronology our marine provenance records show that columbia glacier remained advanced south of this fault into the 21st century columbia glacier has now retreated north of this fault making its recent retreat unprecedented since before ca 0 9 ka southern alaska temperatures have now warmed to pre 0 9 ka levels based on tree ring and reanalysis data we show with glacier model simulations that the warming between c e 1910 and 1980 that includes anthropogenic forcing was sufficient to trigger the recent retreat of columbia glacier from its extended position of the past 0 9 k y consistent with our data driven assessment of the relationship between regional climate change and glacier extent we conclude that the recent retreat of columbia glacier is a response to climate change rather than part of a natural internal tidewater glacier oscillation

the mt logan holocene late wisconsinan isotope record tropical pacific yukon connections the ice core recovered from prospector russell col on mt logan 5 4 km a s l in the yukon spans over 20 000 years this unique record offers a pacific view of the stable isotope and chemical record from the lateglacial to the present the timescale is based on seasonal counted years the largest known volcanic acid signatures and the major shift in stable isotopes and chemistry at the end of the younger dryas there are large and sustained changes in the stable isotopic record that are anti correlated with marine and continental chemistry series the oxygen 18 in this area is not a proxy for palaeotemperature but rather for source region the last major isotope shift in ad 1840 in 18 o and chemistry is compared with the quinn s enso record during periods of more frequent la nina stronger tropical easterlies there is more zonal flow of water vapour transport to the pacific northwest 18 o values are larger and the deuterium excess d smaller these periods coincide with periods of lower accumulation precipitation in southern yukon the holocene 18 o record indicates many large shifts between the meridional strong el nino and zonal la nina comparison of the logan isotopic record and the moisture temperature sensitive time series of peat bog inception dates for the northwest shows a strong correlation 0 36 that points to high accumulation rates coincident with low 18 o and enhanced meridional flow major changes in the core at 4200 bp and 7000 8000 bp point to enhanced meridional flow which coincide with big changes in the pacific palaeorecords of the balance between el nino and la nina 4200 bp seems to have inaugurated the modern enso world

reactive transport modelling of hydrothermal dolomitisation using the csmp gem coupled code effects of temperature and geological heterogeneity abstract reactive transport simulations using our csmp gem coupled code were applied to study the major controls on replacement dolomitisation and the development of dolomite geobodies in a hydrothermal setting a series of 2d simulations show how elevated temperature and reactive surface area increase the rate of dolomitisation and result in a dolomite replacement front that is both sharper and inclined at a higher angle from vertical this inclination an effect of gravity segregation is apparent in thick homogeneous units but in layered systems the lithological contrast determines the shape of the dolomite front the increase in permeability resulting from porosity generation upon replacement of calcite by dolomite has a major effect on accelerating the overall progress of dolomitisation in contrast the changes in fluid density due to chemical reactions and the pressure dependence of thermodynamic data have a minor influence under simulated conditions primary dolomite forms slowly after complete replacement of host calcite leading to porosity decrease and is only locally important around the source of the hydrothermal fluid for a simple layered system our model results are in excellent agreement with those obtained using toughreact code they do however show the advantage of unstructured triangular over structured rectangular meshes for resolving complex curved inclined front shapes such meshes also offer benefits in simulating fault controlled hydrothermal dolomitisation our simulations predict dolomite geobodies comparable in scale and morphology to natural examples documented at outcrops and underline the importance of understanding the permeability structure within and around the fault zone

fault controlled dolomitization in a rift basin there are numerous examples of fault controlled so called hydrothermal dolomite htd many of which host economic mineral deposits or hydrocarbons but there remains a lack of consensus as to how they form in particular multiple phases of diagenetic overprinting can obscure geochemical fingerprints study of a cenozoic succession with a relatively simple burial history here provides new insights into the development of differentially dolomitized beds the hammam faraun fault hff block within the suez rift egypt hosts both massive and stratabound dolostone bodies non fabric selective massive dolostone is limited to the damage zone of the fault while fabric selective stratabound dolostone bodies penetrate nearly 2 km into the footwall oligo miocene seawater is interpreted to have been drawn down discrete faults into a deep aquifer and convected upwards along the hff escape of fluids from the incipient hff into the lower thebes formation led to differential stratabound dolomitization once the hff breached the surface fluid circulation focused along the fault plane to form younger massive dolostone bodies this study provides a snapshot of dolomitization during the earliest phases of extension unobscured by subsequent recrystallization and geochemical modification contrary to many models stratabound dolomitization preceded non stratabound dolomitization fluids were hydrothermal but with little evidence for rapid cooling and brecciation common to many htd bodies these results suggest that many of the features used to interpret and predict the geometry of htd in the subsurface form during later phases of structural deformation perhaps overprinting less structurally complex dolomite bodies

field geometry petrography and geochemistry of a dolomitization front late jurassic central lebanon this contribution describes the field geometry petrography and geochemistry of a well exposed dolomitization front in upper jurassic carbonates and attempts to highlight the sedimentological structural and relative sea level controls on multiphase dolomitization and related diagenetic events the data presented reflect the superposition of various diagenetic phases which have resulted in a single dolostone body whose dimensions are well defined in the field local microbial intraclastic dolomites of late tithonian age accumulated in a hypersaline lagoon during relative sea level fall these pre date beige hydrothermal dolostones 51 to 55 mol caco3 18o 9 3 to 4 0 v pdb 13c 1 5 to 2 1 v pdb 87sr 86sr 0 70742 matrix porosity 6 klinkenberg permeability 0 5 md whose dolomitizing fluid circulated along faults and invaded the nearby facies first the burrows were dolomitized then the bulk rocks resulting in the investigated tongue shaped dolomite body upon late jurassic early cretaceous uplift near surface water percolated through and altered the underlying beige dolostones this event was followed by a ferroan dolomite cement phase which occurred during further burial this contribution featuring a well defined geometric pattern of a dolomitization front with a large petrographic and geochemical data set may also serve as a case study illustrating the complexity of superimposed diagenetic processes which have to be taken into account in modelling exercises of multiphase hydrothermal dolomitization

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

changes in continental and sea salt atmospheric loadings in central greenland during the most recent deglaciation model based estimates by fitting a very simple atmospheric impurity model to high resolution data on ice accumulation and contaminant fluxes in the gisp2 ice core we have estimated changes in the atmospheric concentrations of soluble major ions insoluble particulates and 10 be during the transition from glacial to holocene conditions for many species changes in concentration in the ice typically overestimate atmospheric changes and changes in flux to the ice typically underestimate atmospheric changes because times of increased atmospheric contaminant loading are also times of reduced snowfall the model interpolates between the flux and concentration records by explicitly allowing for wet and dry deposition processes compared to the warm preboreal that followed we estimate that the atmosphere over greenland sampled by snow accumulated during the younger dry as cold event contained on average four seven times the insoluble particulates and nearly seven times the soluble calcium derived from continental sources and about three times the sea salt but only slightly more cosmogenic 10 be

high resolution dinoflagellate cyst record of environmental change in effingham inlet british columbia canada over the last millennium abstract we present a high resolution sedimentary record of dinoflagellate cysts spanning the last 900 years recovered from effingham inlet a glacial fjord on the west coast of vancouver island canada the combination of seasonal coastal upwelling supporting high levels of marine primary productivity in surface waters together with restricted bottom water circulation in the silled fjord fosters the preservation of laminated sediments in the inner basin of effingham inlet geochemical data are used to assess the sedimentary facies of the core which is composed primarily of laminated units 50 2 occasionally interrupted by seismites 39 5 and homogenous units 10 2 the chronology of the 2 m long core is based on varve counting and fifteen 14c dates and is anchored by a seismite previously dated at ad 1946 the dinoflagellate cyst assemblages are diverse total of 47 taxa abundant average concentrations of 102 900 cyst g 1 of dry sediment and characterized by a proportionally equal contribution of autotrophic and heterotrophic cyst taxa in most samples overall cyst assemblages are characterized by operculodinium centrocarpum 36 2 accompanied by brigantedinium spp 18 0 and dubridinium spp 6 6 multivariate analyses are used to extract the dominant patterns of variability in autotrophic and heterotrophic dinoflagellate cyst assemblages separately and help in identifying the temperature and primary productivity gradients encoded in the cyst sedimentary record in this particular estuary specific intervals identified in the dinoflagellate cyst record are interpreted to represent the local expression of the medieval climate anomaly from the base of the record ad 1090 to 1230 the little ice age ad 1230 to late 19th century and warming in the second half of the 20th century the timing of these intervals are consistent with the regional paleoclimate and help constrain past climatic and oceanographic variability on the west coast of vancouver island the origin of homogenous units in the sedimentary record of effingham inlet and paleoseismicity in the region are also discussed

the southern oscillation part i global associations with pressure and temperature in northern winter abstract we describe the global correlations between a measure of the southern oscillation and sea level pressure and surface air temperature in the northern winter the stability of these correlations were tested on the northern hemisphere for an 80 year period and it turned out that most stable correlation coefficients were found over india the north pacific ocean the rocky mountains and the central and western north atlantic ocean on the southern hemisphere most records are too short for a similar test but the following may tentatively be said about the southern oscillation in middle and high southern latitudes when pressure is low in lower latitudes over the south pacific ocean it tends to be high at higher latitudes of that ocean high over east antarctica and low in the belt of westerlies in the indian and south atlantic oceans in the zonal average on both hemispheres the pressure gradients in this extreme of the oscillation tend to be steeper at lower latitudes and flatter at higher latitud

sea level pressure variability in the amundsen sea region inferred from a west antarctic glaciochemical record using european center for medium range weather forecasts ecmwf numerical operational analyses sea ice extent records and station pressure data we investigate the influence of sea level pressure variability in the amundsen sea region on a west antarctic siple dome glaciochemical record empirical orthogonal function analysis of the high resolution siple dome multivariate ice core chemical time series record sdeof1 documents lower tropospheric transport of sea salt aerosols to the site during 1985 1994 the sdeof1 record of high low aerosol transport corresponds to anomalously low high sea level pressure slp in the amundsen sea region spatial correlation patterns between ecmwf monthly slp fields and the annual sdeof1 record suggest that a majority of sea salt aerosol is transported to siple dome during spring september october and november analysis of zonal and meridional wind fields supports the slp sdeof1 correlation and suggests the sdeof1 record is sensitive to changes in regional circulation strength no relationship is found between sea ice extent and the sdeof1 record for the period 1973 1994 to investigate the sdeof1 record prior to ecmwf coverage a spring transpolar index stpi is created using normalized slp records from the new zealand and south america antarctic peninsula sectors and is significantly correlated at least 95 c l with the sdeof1 record on an annual r 5 0 32 p 0 001 and interannual 3 years r 5 0 51 p 0 001 basis dominant periodicities 3 3 and 7 1 years in the annual sdeof1 record 1890 1994 a d suggest that a portion of the recorded interannual variability may be related tropical extratropical enso teleconnections changes in the periodic structure of the full 850 1994 a d siple dome record suggests a shift in slp forcing during the little ice age 1400 1900 a d interval

constituent elements of insoluble and non volatile particles during the last glacial maximum exhibited in the dome fuji antarctica ice core in order to find environmental signals based on the dust and calcium ion concentrations in ice cores we determine the constituent elements of residue particles obtained after melting ice samples we have designed a sublimating system that operates at 458c below the eutectic temperatures of major salts this system permits us to obtain a great many non volatile particles after studying the non volatile particles we immersed them in water to remove soluble particles and compounds we thereby analyzed a total of 1272 residue particles from the melted sample 2418 non volatile particles after sublimation and 1463 insoluble particles taken from five sections of last glacial maximum ice from the dome fuji antarctica ice core their constituent elements were determined by scanning electron microscopy energy dispersive x ray spectrometry sem eds and compared to the dust calcium ion and sodium ion concentrations measured by ion chromatography our results indicate that 99 9 of the insoluble particles contain silicon but no sulfur nitrogen or chlorine a significant number of the non volatile particles however contain sulfur and chlorine we conclude that insoluble dust consists mostly of silicate that almost all calcium ions originate from calcium sulfate and that almost all sodium ions originate from sodium sulfate and sodium chloride